[Federal Register Volume 79, Number 197 (Friday, October 10, 2014)]
[Proposed Rules]
[Pages 61384-61438]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-24009]



[[Page 61383]]

Vol. 79

Friday,

No. 197

October 10, 2014

Part II





Department of Labor





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 Occupational Safety and Health Administration





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29 CFR Parts 1910, 1915, 1917, et al.





 Chemical Management and Permissible Exposure Limits (PELs); Proposed 
Rule

  Federal Register / Vol. 79 , No. 197 / Friday, October 10, 2014 / 
Proposed Rules  

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DEPARTMENT OF LABOR

Occupational Safety and Health Administration

29 CFR Parts 1910, 1915, 1917, 1918, and 1926

[Docket No. OSHA 2012-0023]
RIN 1218-AC74


Chemical Management and Permissible Exposure Limits (PELs)

AGENCY: Occupational Safety and Health Administration (OSHA), DOL.

ACTION: Request for Information (RFI).

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SUMMARY: OSHA is reviewing its overall approach to managing chemical 
exposures in the workplace and seeks stakeholder input about more 
effective and efficient approaches that addresses challenges found with 
the current regulatory approach. This review involves considering 
issues related to updating permissible exposure limits (PELs), as well 
as examining other strategies that could be implemented to address 
workplace conditions where workers are exposed to chemicals. The notice 
details the role of past court decisions on the Agency's current 
approach to chemical management for the purpose of informing 
stakeholders of the legal framework in which the Agency must operate. 
It then describes possible modifications of existing processes, along 
with potential new sources of data and alternative approaches the 
Agency may consider. The Agency is particularly interested in 
information about how it may take advantage of newer approaches, given 
its legal requirements. This RFI is concerned primarily with chemicals 
that cause adverse health effects from long-term occupational exposure, 
and is not related to activities being conducted under Executive Order 
13650, Improving Chemical Facility Safety and Security.

DATES: Comments must be submitted by the following dates:
    Hard copy: must be submitted (postmarked or sent) by April 8, 2015.
    Electronic transmission or facsimile: must be submitted by April 8, 
2015.

ADDRESSES: Comments may be submitted by any of the following methods:
    Electronically: Submit comments electronically at: 
www.regulations.gov, which is the Federal eRulemaking Portal. Follow 
the instructions online for making electronic submissions.
    Fax: Submissions no longer than 10-pages (including attachments) 
may be faxed to the OSHA Docket Office at (202) 693-1648.
    Mail, hand delivery, express mail, or messenger or courier service: 
Copies must be submitted in triplicate (3) to the OSHA Docket Office, 
Docket No. OSHA-2012-0023, U.S. Department of Labor, Room N-2625, 200 
Constitution Avenue NW., Washington, DC 20210. Deliveries (hand, 
express mail, messenger, and courier service) are accepted during the 
Department of Labor and Docket Office's normal business hours, 8:15 
a.m. to 4:45 p.m. (E.T.).
    Instructions: All submissions must include the Agency name and the 
OSHA docket number (i.e. OSHA-2012-0023). Submissions, including any 
personal information provided, are placed in the public docket without 
change and may be made available online at: www.regulations.gov. OSHA 
cautions against the inclusion of personally identifiable information 
(e.g., social security number, birth dates).
    If you submit scientific or technical studies or other results of 
scientific research, OSHA requests that you also provide the following 
information where it is available: (1) Identification of the funding 
source(s) and sponsoring organization(s) of the research; (2) the 
extent to which the research findings were reviewed by a potentially 
affected party prior to publication or submission to the docket, and 
identification of any such parties; and (3) the nature of any financial 
relationships (e.g., consulting agreements, expert witness support, or 
research funding) between investigators who conducted the research and 
any organization(s) or entities having an interest in the rulemaking. 
If you are submitting comments or testimony on the Agency's scientific 
and technical analyses, OSHA requests that you disclose: (1) The nature 
of any financial relationships you may have with any organization(s) or 
entities having an interest in the rulemaking; and (2) the extent to 
which your comments or testimony were reviewed by an interested party 
prior to its submission. Disclosure of such information is intended to 
promote transparency and scientific integrity of data and technical 
information submitted to the record. This request is consistent with 
Executive Order 13563, issued on January 18, 2011, which instructs 
agencies to ensure the objectivity of any scientific and technological 
information used to support their regulatory actions. OSHA emphasizes 
that all material submitted to the rulemaking record will be considered 
by the Agency to develop the final rule and supporting analyses.
    Docket: To read or download submissions or other material in the 
docket go to: www.regulations.gov or the OSHA Docket Office at the 
address above. All documents in the docket are listed in the index; 
however, some information (e.g. copyrighted materials) is not publicly 
available to read or download through the Web site. All submissions, 
including copyrighted material, are available for inspection and 
copying at the OSHA Docket Office.

FOR FURTHER INFORMATION CONTACT: General information and press 
inquiries: Mr. Frank Meilinger, Director, Office of Communications, U. 
S. Department of Labor, Room N-3647, 200 Constitution Avenue NW., 
Washington, DC 20210, telephone (202) 693-1999; email 
[email protected]. Technical information: Ms. Lyn Penniman, 
Office of Physical Hazards, OSHA, Room N-3718, 200 Constitution Avenue 
NW., Washington, DC 20210, telephone (202) 693-1950; email 
[email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Purpose
II. Legal Requirements for OSHA Standards
    A. Significant Risk of a Material Impairment: The Benzene Case
    B. Technological and Economic Feasibility
    C. The Substantial Evidence Test
III. History of OSHA's Efforts To Establish PELs
    A. Adopting the PELs in 1971
    B. The 1989 PELs Update
    C. The 1989 PELs Update is Vacated
    D. Revising OSHA's PELs in the Wake of the Eleventh Circuit 
Decision
IV. Reconsideration of Current Rulemaking Processes
    A. Considerations for Risk Assessment Methods
    1. Current Quantitative Risk Assessment Methods Typically Used 
by OSHA To Support 6(b) Single Substance Rulemaking
    2. Proposed Tiered Approach to Risk Assessment in Support of 
Updating PELs for Chemical Substances
    a. General Description and Rationale of Tiered Approach
    b. Hazard Identification and Dose-Response Analysis in the 
Observed Range
    c. Derivation of Low-End Toxicity Exposure (LETE)
    d. Margin of Exposure (MOE) as a Decision Tool for Low Dose 
Extrapolation
    e. Extrapolation Below the Observed Range
    3. Chemical Grouping for Risk Assessment
    a. Background on Chemical Grouping
    b. Methods of Gap Analysis and Filling
    i. Read-Across Method
    ii. Trend Analysis
    iii. QSAR
    iv. Threshold of Toxicological Concern
    4. Use of Systems Biology and Other Emerging Test Data in Risk 
Assessment
    B. Considerations for Technological Feasibility

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    1. Legal Background of Technological Feasibility
    2. Current Methodology of the Technological Feasibility 
Requirement
    3. Role of Exposure Modeling in Technological Feasibility
    a. Computational Fluid Dynamics Modeling To Predict Workplace 
Exposures
    b. The Potential Role of REACH in Technological Feasibility
    c. Technological Feasibility Analysis With a Focus on Industries 
with Highest Exposures
    C. Economic Feasibility for Health Standards
    1. OSHA's Current Approach to Economic Feasibility
    2. Alternative Approaches to Formulating Health Standards that 
Might Accelerate the Economic Feasibility Analysis
    3. Alternative Analytical Approaches to Economic Feasibility in 
Health Standards
    4. Approaches to Economic Feasibility Analysis for a 
Comprehensive PELs Update
V. Recent Developments and Potential Alternative Approaches
    A. Sources of Information About Chemical Hazards
    1. EPA's High Production Volume Chemicals
    2. EPA's CompTox and ToxCast
    3. Production and Use Data Under EPA's Chemical Data Reporting 
Rule
    4. Structure-Activity Data for Chemical Grouping
    5. REACH: Registration, Evaluation, Authorization, and 
Restriction of Chemicals in the European Union (EU)
    B. Non-OEL Approaches to Chemical Management
    1. Informed Substitution
    2. Hazard Communication and the Globally Harmonized System (GHS)
    3. Health Hazard Banding
    4. Occupational Exposure Bands
    5. Control Banding
    6. Task-based Exposure Assessment and Control Approaches
VI. Authority and Signature
Appendix A: History, Legal Background and Significant Court 
Decisions
Appendix B: 1989 PELs Table
List of References by Exhibit Number

List of Acronyms: Request for Information on Chemical Management and 
Permissible Exposure Limits

ACGIH American Conference of Governmental Industrial Hygienists
ADI Allowable Daily Intake
AIHA American Industrial Hygiene Association
AISI American Iron and Steel Institute
ANSI American National Standards Institute
APHA American Public Health Association
ATSDR Agency for Toxic Substances Disease Registry
BAuA Federal Institute for Occupational Safety and Health (Germany)
BMD Benchmark Dose
BMDL Benchmark Dose Low
BMR Benchmark Response
CDR Chemical Data Reporting
CFD Computational Fluid Dynamics
COSHH Control of Substances Hazardous to Health (U.K.)
CrVI Hexavalent Chromium
CSTEE Scientific Committee on Toxicity, Ecotoxicity and the 
Environment (E.U.)
CT Control Technology
DfE Design for the Environment (EPA)
DHHS Department of Health and Human Services (U.S.)
DMEL Derived Minimal Effect Level
DNEL Derived No Effect Level
DOE Washington Department of Ecology
DOL Department of Labor (U.S.)
ECB European Chemicals Bureau (E.U.)
ECHA European Chemicals Agency (E.U.)
EPA Environmental Protection Agency (U.S.)
ES Exposure Scenario
EU European Union
FDA Food and Drug Administration (U.S.)
GAO Government Accountability Office (U.S.)
GHS Globally Harmonized System for the Classification and Labeling 
of Chemicals
HazCom 2012 Revised OSHA Hazard Communication Standard
HCS Hazard Communication Standard (OSHA)
HHE Health Hazard Evaluation (NIOSH)
HPV High Production Volume (EPA)
HPVIS High Production Volume Information System (EPA)
HSE Health and Safety Executive (U.K.)
HTS High Throughput Screening
IFA Federation of Institutions for Statutory Accident Insurance and 
Prevention (Germany)
IMIS Integrated Management Information System (OSHA)
IPCS World Health Organization International Programme on Chemical 
Safety
IRIS Integrated Risk Information System (EPA)
ISTAS Institute of Work, Environment, and Health (Spain)
ITC Interagency Testing Committee (EPA TSCA)
IUR Inventory Update Reporting
LETE Low-end Toxicity Exposure
LOAEL Lowest Observed Adverse Effect Level
LOD Limit of Detection
LTFE Lowest Technologically Feasible Exposure
MA DEP Massachusetts Department of Environmental Protection
MIBK Methyl isobutyl ketone
MOA Modes of Action
MOE Margin of Exposure
MRL Minimal Risk Level
NAICS North American Industry Classification System
NCGC National Institutes of Health Chemical Genomics Center
NIEHS National Institute of Environmental Health Sciences (U.S.)
NIOSH National Institute for Occupational Safety and Health (U.S.)
NIST National Institute of Standards and Technology (U.S.)
NMCSD Navy Medical Center San Diego
NOAEL No Observed Adverse Effect Level
NOES National Occupational Exposure Survey
NORA National Occupational Research Agenda (NIOSH)
NPRM Notice of Proposed Rulemaking (OSHA)
NRC National Research Council (U.S., private)
NTP National Toxicology Program (U.S.)
OECD Organization for Economic Cooperation and Development (multiple 
countries, private)
OEL Occupational Exposure Limit
OPPT Office of Pollution Prevention and Toxics (EPA)
OSHA Occupational Safety and Health Administration
OTA Massachusetts Office of Technical Assistance and Technology
PBT Persistent, Bioaccumulative and Toxic
PBZ Personal Breathing Zone
PCRARM (EPA) Presidential/Congressional Commission on Risk 
Assessment and Risk Management
PEL Permissible Exposure Limits
PMN Pre-manufacture Notification (EPA)
PNEC Predicted No Effect Concentration
POD Point of Departure
PPE Personal Protective Equipment
PPM Parts Per Million
QCAT Quick Chemical Assessment Tool (DOE)
QSAR Quantitative Structure-Activity Relationship
REACH Registration, Evaluation, Authorization and Restriction of 
Chemicals (E.U.)
REL Recommended Exposure Level
RfC Reference Concentration
RFI Request for Information
SAR Structural Activity Relation
SBREFA Small Business Regulatory Enforcement Fairness Act (U.S.)
SDS Safety Data Sheet
SEP Special Emphasis Program
SIC Standards Industrial Classification
SIDS Screening Information Data Set (OECD)
STEL Short-term Exposure Limit
TLV Threshold Value Limit (ACGIH)
TSCA Toxic Substances Control Act (EPA)
TTC Threshold of Toxicological Concern
TWA Time-weighted Average
vPvB Very Persistent and Very Bioaccumulative
WEEL Workplace Environmental Exposure Level (AIHA)

I. Purpose

    The purpose of this Request for Information (RFI) is to present 
background information and request comment on a number of technical 
issues related to aspects of OSHA's rulemaking process for chemical 
hazards in the workplace. In particular, the purpose of the RFI is to:
     Review OSHA's current approach to chemical regulation in 
its historical context;
     Describe and explore other possible approaches that may be 
relevant to future strategies to reduce and control exposure to 
chemicals in the workplace; and
     Inform the public and obtain public input on the best 
approaches for the

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Agency to advance the development and implementation of approaches to 
reduce or eliminate harmful chemical exposures in the 21st century 
workplace.
    By all estimates, the number of chemicals found in workplaces today 
far exceeds the number which OSHA regulates, and is growing rapidly. 
There is no single source recording all chemicals available in 
commerce. Through its Chemical Data Reporting Rule, EPA collects 
information on chemicals manufactured or imported at a single site at 
25,000 pounds or greater; currently this number exceeds 7,674 chemicals 
(U.S. EPA, 2013a; Ex. #1)
    The American Chemistry Council estimates that approximately 8,300 
chemicals (or about 10 percent of the 87,000 chemicals in the TSCA 
inventory) are actually in commerce in significant amounts (Hogue, 
2007; Ex. #2). By contrast the European Chemicals Agency database 
contains 10,203 unique substances (as of 9/12/2013) (ECHA, 2013; Ex. 
#3). Of these, OSHA has occupational exposure limits for only about 470 
substances. Most of these are listed as simple limits and appear in 
tables (referred to as ``Z-tables'') in 29 CFR 1910.1000, Air 
Contaminants, Subpart Z, Toxic and Hazardous Substances; Ex. #4. 
Approximately 30 have been adopted by OSHA as a part of a comprehensive 
standard, and include a number of additional requirements such as 
regulated areas, air sampling, medical monitoring, and training 
However, with few exceptions, OSHA's permissible exposure limits, 
(PELs), which specify the amount of a particular chemical substance 
allowed in workplace air, have not been updated since they were 
established in 1971 under expedited procedures available in the short 
period after the OSH Act's adoption (see 29 CFR 1910.1000; Ex. #4, 
1915.1000; Ex. #5, and 1926.55; Ex. #6). Yet, in many instances, 
scientific evidence has accumulated suggesting that the current limits 
are not sufficiently protective. Although OSHA has attempted to update 
its PELs, the Agency has not been successful, except through the 
promulgation of a relatively few substance-specific health standard 
rulemakings (e.g., benzene, cadmium, lead, and asbestos).
    The most significant effort to update the PELs occurred in 1989 
when OSHA tried to update many of its outdated PELs and to create new 
PELs for other substances in a single rulemaking covering general 
industry PELs. After public notice and comment, the Agency published a 
general industry rule that lowered PELs for 212 chemicals and added new 
PELs for 164 more (54 FR 2332; Ex. #7). Appendix B to this Request for 
Information contains the table of PELs from the 1989 Air Contaminants 
Final Rule. The table includes both the PELs originally adopted by OSHA 
in 1971 and the PELs established under the 1989 final rule. While the 
Agency presented analyses of the risks associated with these chemicals, 
as well as the analyses of the economic and technological feasibility 
of the proposed limits for these chemicals, these analyses were not as 
detailed as those OSHA would have prepared for individual rulemakings. 
The final rule was challenged by both industry and labor groups. The 
1989 PEL update was vacated by the Eleventh Circuit Court of Appeals 
because it found that OSHA had not made sufficiently detailed findings 
that each new PEL would eliminate significant risk and would be 
feasible in each industry in which the chemical was used. (AFL-CIO v. 
OSHA, 965 F.2d 962 (11th Cir. 1992) (the Air Contaminants case; Ex. 
#8). This decision is discussed further below and in Appendix A.
    Despite these challenges, health professionals and labor and 
industry groups have continued to support addressing PELs which may be 
outdated and or inconsistent with the best available current science. 
The 1989 Air Contaminants rulemaking effort was supported by the 
American Industrial Hygiene Association (AIHA), the American Conference 
of Governmental Industrial Hygienists (ACGIH), and the American Public 
Health Association (APHA), among many other professional organizations 
and associations representing both industry and labor. In an October 
2012 survey, members of the AIHA identified updating OSHA PELs as their 
number one policy priority. The U.S. Chamber of Commerce, in a letter 
dated April 8, 2011 to then Deputy Secretary of Labor, Seth Harris, 
also supported updating OSHA's PELs.
    Much has changed in the world since the OSH Act was signed in 1970. 
However, workers are essentially covered by the same PELs as they were 
forty years ago. And while OSHA has been given no new tools or 
increased resources to control workplace exposures, it has had to 
conduct increasingly complex analyses, which has effectively slowed the 
process. The purpose of this RFI is for OSHA to solicit information as 
to the best approach(es) for the Agency to help employers and employees 
devise and implement risk management strategies to reduce or eliminate 
chemical exposures in the 21st century workplace environment. This is 
likely to involve a multi-faceted plan that may include changing or 
improving OSHA policies and procedures regarding the derivation and 
implementation of PELs, as well as pursuing new strategies to improve 
chemical management in the workplace. The Agency is publishing this 
notice to inform the public of its consideration of these issues, as 
well as solicit public input that can be used to inform further 
deliberations, and the determination of an appropriate approach.

II. Legal Requirements for OSHA Standards

    In the past, OSHA has received many suggestions for updating its 
PELs, but these suggestions often do not take account of the 
requirements imposed by the OSH Act, and thus have been of limited 
value to OSHA. OSHA is providing an overview of its legal requirements 
for setting standards in order to help commenters responding to this 
RFI to provide suggestions that can satisfy these requirements. This 
section summarizes OSHA's legal requirements, which are discussed in 
greater detail in Appendix A. The next section provides an overview of 
OSHA's previous attempts to update the PELs.
    Section 6(b) of the OSH Act (Ex. #9) provides OSHA with the 
authority to promulgate health standards. It specifies procedures that 
OSHA must use to promulgate, modify, or revoke its standards, including 
publishing the proposed rule in the Federal Register, providing 
interested persons an opportunity to comment, and holding a public 
hearing upon request. However, much of the labor and analysis that goes 
into the final rule starts before the publication of the proposal. 
Section 6(b)(5) of the Act specifies:

    The Secretary, in promulgating standards dealing with toxic 
materials or harmful physical agents under this subsection, shall 
set the standard which most adequately assures, to the extent 
feasible, on the basis of the best available evidence, that no 
employee will suffer material impairment of health or functional 
capacity even if such employee has regular exposure to the hazard 
dealt with by such standard for the period of his working life. 
Development of standards under this subsection shall be based upon 
research, demonstrations, experiments, and such other information as 
may be appropriate. In addition to the attainment of the highest 
degree of health and safety protection for the employee, other 
considerations shall be the latest available scientific data in the 
field, the feasibility of the standards, and experience gained under 
this and other health and safety laws. Whenever practicable, the 
standard promulgated shall be expressed in terms of objective 
criteria and of the performance desired.

    In general, as this provision has been construed by the courts, any 
workplace

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health standard adopted by OSHA must meet the following requirements:
    (1) The standard must substantially reduce a significant risk of 
material harm.
    (2) Compliance with the standard must be technically feasible. This 
means that the protective measures required by the standard currently 
exist, can be brought into existence with available technology, or can 
be created with technology that can reasonably be developed.
    (3) Compliance with the standard must be economically feasible. 
This means that the standard will not threaten the industry's long term 
profitability or substantially alter its competitive structure.
    (4) It must reduce risk of adverse health to workers to the extent 
feasible.
    (5) The standard must be supported by substantial evidence in the 
record, consistent with prior agency practice or is supported by some 
justification for departing from that practice.
    The significant risk, economic and technological feasibility, and 
substantial evidence requirements are of particular relevance in 
setting PELs, and are discussed further below.

A. Significant Risk of a Material Impairment: The Benzene Case

    The significant risk requirement was first articulated in a 
plurality decision of the Supreme Court in Industrial Union Department, 
AFL-CIO v. American Petroleum Institute, 448 U.S. 607 (1980), commonly 
referred to as the Benzene case. The petitioners challenged OSHA's rule 
lowering the PEL for benzene from 10 ppm to 1 ppm. In support of the 
new PEL, OSHA found that benzene caused leukemia and that the evidence 
did not show that there was a safe threshold exposure level below which 
no excess leukemia would occur; OSHA chose the new PEL of 1 ppm as the 
lowest feasible exposure level. The Benzene Court rejected OSHA's 
approach, finding that the OSH Act only required that employers ensure 
that their workplaces are safe, that is, that their workers are not 
exposed to ``significant risk[s] of harm.'' 448 U.S. at 642 (Ex. #10). 
The Court also made it clear that it is OSHA's burden to establish that 
a significant risk is present at the current standard before lowering a 
PEL, stating that the burden of proof is normally on the proponent. 
Thus, the Court held, before promulgating a health standard, OSHA is 
required to make a ``threshold finding that a place of employment is 
unsafe--in the sense that significant risks are present and can be 
eliminated or lessened by a change in practices'' before it can adopt a 
new standard. Id.
    Although the Court declined to establish a set test for determining 
whether a workplace is unsafe, it did state that a significant risk was 
one that a reasonable person would consider significant and ``take 
appropriate steps to decrease or eliminate.'' 448 U.S. at 655. For 
example, it said, a one in a 1,000 risk would satisfy the requirement. 
However, this example was merely an illustration, not a hard line rule. 
The Court made it clear that determining whether a risk was 
``significant'' was not a ``mathematical straitjacket'' and did not 
require the Agency to calculate the exact probability of harm. Id. The 
1 ppm PEL was vacated because OSHA had not made a significant risk 
finding at the 10 ppm level.
    Following the Benzene case, OSHA has satisfied the significant risk 
requirement by estimating the risk to workers subject to a lifetime of 
exposure at various possible exposure levels. These estimates have 
typically been based on quantitative risk assessments in which OSHA, as 
a general policy, has considered an excess risk of one death per 1000 
workers over a 45-year working lifetime as clearly representing a 
significant risk. However, the Benzene case does not require OSHA to 
use such a benchmark. In the past, OSHA has stated that a lower risk of 
death could be considered significant. See, e.g., Preamble to 
Formaldehyde Standard, 52 FR 46168, 46234 (suggesting that risk 
approaching six in a million could be viewed as significant). (Ex. #11)

B. Technological and Economic Feasibility

    Under section 6(b)(5) of the Act, a standard must protect against 
significant risk, ``to the extent feasible, and feasibility is 
understood to have both technological and economic aspects. A standard 
is technologically feasible if ``a typical firm will be able to develop 
and install engineering and work practice controls that can meet the 
PEL in most operations.'' United Steelworkers v. Marshall, 647 F.2d 
1189, 1272 (D.C. Cir. 1981) (``Lead I''; Ex. #12). OSHA must show the 
existence of ``technology that is either already in use or has been 
conceived and is reasonably capable of experimental refinement and 
distribution within the standard's deadlines.'' Id. Where the Agency 
presents ``substantial evidence that companies acting vigorously and in 
good faith can develop the technology,'' the Agency is not bound to the 
technological status quo, and ``can require industry to meet PELs never 
attained anywhere.'' Id. at 1264-65.
    Some courts have required OSHA to determine whether a standard is 
technologically feasible on an industry-by-industry basis, Color 
Pigments Manufacturers Assoc. v. OSHA, 16 F.3d 1157, 1162-63 (11th Cir. 
1994; Ex. #13); AFL-CIO v. OSHA, 965, F.2d 962, 981-82 (11th Cir. 1992) 
(Air Contaminants; Ex. #8). However, another court has upheld 
technological feasibility findings based on the nature of an activity 
across many industries rather than on an industry-by-industry basis, 
Public Citizen Health Research Group v. United States Department of 
Labor, 557 F.3d 165,178-79 (3d Cir. 2009; Ex. #14).
    With respect to economic feasibility, the courts have stated ``A 
standard is feasible if it does not threaten massive dislocation to . . 
. or imperil the existence of the industry.'' Lead I, 647 F.2d at 1265 
(Ex. #12). In order to show this, OSHA should ``construct a reasonable 
estimate of compliance costs and demonstrate a reasonable likelihood 
that these costs will not threaten the existence or competitive 
structure of an industry.'' Id. at 1266. However, ``[T]he court 
probably cannot expect hard and precise estimates of costs. 
Nevertheless, the agency must of course provide a reasonable assessment 
of the likely range of costs of its standard, and the likely effects of 
those costs on the industry.'' Id.
    While OSHA is not required to show that all companies within an 
industry will be able to bear the burden of compliance, at least one 
court has held that OSHA is required to show that the rule is 
economically feasible on an industry-by-industry basis. Air 
Contaminants, 965 F.2d at 982, 986. (Ex. #8)

C. The Substantial Evidence Test

    The ``substantial evidence test'' is used by the courts to 
determine whether OSHA has reached its burden of proof for policy 
decisions and factual determinations. ``Substantial evidence'' is 
defined as ``such relevant evidence as a reasonable mind might accept 
as adequate to support a conclusion.'' American Textile Mfrs. Inst., 
Inc. v. Donovan, 452 U.S. 490, 522 (1981; Ex. #15) (quoting Universal 
Camera Corp. v. NLRB, 340 U.S. 474, 477 (1951); Ex. #16). The 
substantial evidence test does not require ``scientific certainty'' 
before promulgating a health standard (AFL-CIO v. American Petroleum 
Institute, 448 U.S. 607, 656 (1980); Ex. 10), but the test does require 
OSHA to ``identify relevant factual evidence, to explain the logic and 
the policies underlying any legislative choice, to state candidly any

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assumptions on which it relies, and to present its reasons for 
rejecting significant contrary evidence and argument.'' Lead I, 647 
F.2d. at 1207. (Ex. #12)

III. History of OSHA's Efforts To Establish PELs

    The history of OSHA's PELs has three stages. First, OSHA adopted 
its current PELs in 1971, shortly after coming into existence. Second, 
OSHA attempted to update its PELs wholesale in 1989, but that effort 
was rejected by the Eleventh Circuit Court of Appeals in 1992. Third, 
OSHA has made subsequent, smaller efforts to update certain PELs, but 
those efforts have never come to fruition. This history is summarized 
below, and discussed in further detail in Appendix A.

A. Adopting the PELs in 1971

    Under section 6(a), OSHA was permitted an initial two-year window 
after the passage of the OSH Act to adopt ``any national consensus 
standard and any established Federal standard'' 29 U.S.C 655(6)(a). 
OSHA used this authority in 1971 to establish PELs that were adopted 
from federal health standards originally set by the Department of Labor 
through the Walsh-Healy Act, in which approximately 400 occupational 
exposure limits were selected based on ACGIH's 1968 list of Threshold 
Limit Values (TLVs). In addition, about 25 additional exposure limits 
recommended by the American Standards Association (now called the 
American National Standards Institute) (ANSI), were adopted as national 
consensus standards.
    These standards were intended to provide initial protections for 
workers from what the Congress deemed to be the most dangerous 
workplace threats. Congress found it was ``essential that such 
standards be constantly improved and replaced as new knowledge and 
techniques are developed.'' S. Rep. 91-1282 at 6. (Ex. #17) However, 
because OSHA has been unable to update the PELs, they remain frozen at 
the levels at which they were initially adopted. OSHA's PELs are also 
largely based on acute health effects and do not take into 
consideration newer research regarding chronic health effects occurring 
at lower occupational exposures.

B. The 1989 PELs Update

    In 1989, OSHA published the Air Contaminants final rule, which 
remains the Agency's most significant attempt at updating the PELs (54 
FR 2332). (Ex. #7) Unlike typical substance-specific rulemakings, where 
OSHA develops a comprehensive standard, the Air Contaminants final rule 
was only intended to update existing PELs or to add PELs for substances 
within established boundaries. After extensive review of all available 
sources of occupational exposure limits (OELs), OSHA selected the 
ACGIH's 1987-88 TLVs as the boundaries for identifying the substances 
that would be included in the proposed rule. OSHA proposed 212 more 
protective PELs and new PELs for 164 substances not previously 
regulated. In general, rather than performing a quantitative risk 
assessment for each chemical, the agency looked at whether studies 
showed excess effects of concern at concentrations lower than allowed 
under the existing standard. Where they did, OSHA made a significant 
risk finding and either set a PEL (where none existed previously) or 
lowered the existing PEL. These new PELs were based on Agency judgment, 
taking into account the existing studies and, as appropriate, safety 
factors. Safety factors (also called uncertainty factors) are applied 
to the lowest level an effect is seen or to a level where no effects 
are seen to derive a PEL.
    In order to determine whether the Air Contaminants rule was 
feasible, OSHA prepared the regulatory impact analysis. As part of the 
analysis, OSHA performed an industry survey as well as site visits. The 
survey was the largest survey ever conducted by OSHA and included 
responses from 5,700 firms in industries believed to use chemicals 
addressed in the scope of the Air Contaminants proposal. (Ex. #18) It 
was designed to focus on industry sectors that potentially had the 
highest compliance costs, identified through an analysis of existing 
exposure data at the four-digit SIC (Standards Industrial 
Classification) code level. OSHA analyzed the data collected to 
determine whether the updated PELs were both technologically and 
economically feasible for each industry sector covered.
    For technological feasibility, OSHA found that ``in the 
overwhelming majority of situations where air contaminants [were] 
encountered by workers, compliance [could] be achieved by applying 
known engineering control methods, and work practice improvements.'' 54 
FR at 2789; Ex. #7. For economic feasibility, OSHA assessed the 
economic impact of the standard on industry profits at the two-digit 
SIC code level, and found the economic impact not to be significant, 
and the new standard therefore economically feasible.
    In the Air Contaminants final rule, OSHA summarized the health 
evidence for each individual substance, discussed over 2,000 studies, 
reviewed and addressed all major comments submitted to the record, and 
provided a rationale for each new PEL chosen. OSHA estimated that over 
21 million employees were potentially exposed to hazardous substances 
in the workplace and over 4.5 million employees were exposed to levels 
above the applicable exposure limits. OSHA projected that the final 
rule would result in a potential reduction of over 55,000 lost workdays 
due to illnesses per year and that annual compliance with this final 
rule would prevent an average of 683 fatalities annually from exposures 
to hazardous substances.

C. The 1989 PELs Update Is Vacated by the Court of Appeals

    The update to the Air Contaminants standard generally received 
widespread support from both industry and labor. However, there was 
dissatisfaction on the part of some industry representatives and union 
leaders, who brought petitions for review challenging the standard. For 
example, some industry petitioners argued that OSHA's use of generic 
findings, the inclusion of so many substances in one rulemaking, and 
the allegedly insufficient time provided for comment by interested 
parties created a record inadequate to support the new set of PELs. In 
contrast, the unions challenged the approach used by OSHA to promulgate 
the standard and argued that several PELs were not protective enough. 
The unions also asserted that OSHA's failure to include any ancillary 
provisions, such as exposure monitoring and medical surveillance, 
prevented employers from ensuring the exposure limits were not 
exceeded, and resulted in less-protective PELs.
    Although only 23 of the 428 PELs were challenged, the court 
ultimately decided to vacate the entire rulemaking, finding that ``OSHA 
[had] not sufficiently explained or supported its threshold 
determination that exposure to these substances at previous levels 
posed a significant risk of these material health impairments or that 
the new standard eliminates or reduces that risk to the extent 
feasible.'' Air Contaminants 965 F.2d at 986-987; Ex. #8
    With respect to significant risk, the court held that OSHA had 
failed to ``explain why the studies mandated a particular PEL chosen.'' 
Id. at 976. Specifically, the court stated that OSHA failed to quantify 
the risk from individual substances and merely provided conclusory 
statements that the new PEL would reduce a significant risk

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of material health effects.'' Id. at 975. Further, the court rejected 
OSHA's argument that it had relied on safety factors in setting the new 
PELs, stating that OSHA had not adequately supported their use. The 
court observed that ``the difference between the level shown by the 
evidence and the final PEL is sometimes substantial.'' Id. at 978. It 
said that OSHA had not indicated ``how the existing evidence for 
individual substances was inadequate to show the extent of risk for 
these factors'' and that the agency had ``failed to explain the method 
by which its safety factors were determined.'' Id. ``OSHA may use 
assumptions but only to the extent that those assumptions have some 
basis in reputable scientific evidence,'' the court concluded. Id. at 
978-79.
    The Eleventh Circuit court also rejected OSHA's technological 
feasibility findings. The Agency had made these findings mainly at the 
two-digit SIC level, but also at the three- and four- digit level where 
appropriate given the processes involved. The court rejected this 
approach, finding that OSHA failed to make industry-specific findings 
or identify the specific technologies capable of meeting the proposed 
limit in industry-specific operations. Id. at 981. While OSHA had 
identified primary air contaminant control methods: Engineering 
controls, administrative controls and work practices and personal 
protective equipment, the agency, ``only provided a general description 
of how the generic engineering controls might be used in the given 
sector.'' Id. Though noting that OSHA need only provide evidence 
sufficient to justify a ``general presumption of feasibility,'' the 
court held that this ``does not grant OSHA license to make overbroad 
generalities as to feasibility or to group large categories of 
industries together without some explanation of why findings for the 
group adequately represents the different industries in that group.'' 
Id. at 981-82.
    The court rejected OSHA's economic feasibility findings for similar 
reasons. As discussed above, OSHA supported its economic feasibility 
findings for the 1989 Air Contaminants rule based primarily on the 
results of a survey of over 5700 businesses, summarizing the projected 
cost of compliance at the two-digit SIC industry sector level. The 
court held that OSHA was required to show that the rule was 
economically feasible on an industry-by industry basis, and that OSHA 
had not shown that its analyses at the two-digit SIC industry sector 
level were appropriate to meet this burden. Id. at 982. ``[A]verage 
estimates of cost can be extremely misleading in assessing the impact 
of particular standards on individual industries'' the court said, and 
``analyzing the economic impact for an entire sector could conceal 
particular industries laboring under special disabilities and likely to 
fail as a result of enforcement.'' Id. While OSHA might ``find and 
explain that certain impacts and standards do apply to entire sectors 
of an industry'' if ``coupled with a showing that there are no 
disproportionately affected industries within the group,'' OSHA had not 
explained why its use of such a ``broad grouping was appropriate.'' Id. 
at 982 n.28, 983.

D. Revising OSHA's PELs in the Wake of the Eleventh Circuit Decision

    In the wake of the Eleventh Circuit's decision, OSHA has generally 
pursued a conservative course in satisfying its judicially imposed 
analytical burdens. The set of resulting analytical approaches OSHA has 
engaged in is highly resource-intensive and has constrained OSHA's 
ability to prioritize its regulatory efforts based on risk of harm to 
workers. In 1995, OSHA made its first attempt following the Air 
Contaminants ruling to update a smaller number of PELs using a more 
rigorous analysis of risk, workplace exposures, and technological and 
economic feasibility. (Ex. #20) OSHA and the National Institute for 
Occupational Safety and Health (NIOSH) conducted preliminary research 
on health risks associated with exposure and extent of occupational 
exposure. Sixty priority substances were identified for further 
examination and twenty of the sixty substances were selected to form a 
priority list. Early in 1996, the Agency announced its plans for a 
stakeholder meeting, and identified the twenty priority substances, as 
well as several risk-related discussion topics. (Ex. #21) During the 
meeting, almost all stakeholders from industry and labor agreed that 
the PELs needed to be updated; however, not one group completely 
supported OSHA's suggested approach. Overall, many of the stakeholders 
did not support the development of a list of priority chemicals 
targeted for potential regulation and felt there was a lack of 
transparency in the process for selecting the initial chemicals.
    In response to stakeholder input and OSHA's research, the agency 
selected seven of the 20 substances discussed at the stakeholder 
meeting for detailed analysis of risks and feasibility. The chemicals 
selected were: (i) Glutaraldehyde, (ii) carbon disulfide, (iii) 
hydrazine, (iv) perchloroethylene, (v) manganese, (vi) trimellitic 
anhydride, and (vii) chloroprene. Quantitative risk assessments were 
performed in-house, and research (including site visits) was undertaken 
to collect detailed data on uses, worker exposures, exposure control 
technology effectiveness, and economic characteristics of affected 
industries.
    The research and analysis were carried out over several years, 
after which OSHA decided not to proceed with rulemaking. (Ex. #22) This 
decision was influenced by findings that (i) prevalence and intensity 
of worker exposures for some of the substances (e.g., carbon disulfide 
and hydrazine) had declined substantially since the 1989 rule was 
promulgated; (ii) industry had voluntarily implemented controls to 
reduce the exposure to safe levels; and (iii) for others, substantial 
Agency resources would have been required to fully assess technological 
and economic impacts.
    In 1997, OSHA held another meeting with industry and labor on the 
proposed PEL development process. Although the project did not result 
in a rulemaking to revise the PELs, OSHA gained valuable experience in 
developing useful approaches for quantifying non-cancer health risks 
through collaboration with external reviewers in scientific peer 
reviews of its risk analyses. OSHA is now examining ways to better 
address chemical exposures given current resource constraints and 
regulatory limitations.
    For readers who are interested in a more detailed account of the 
legislation and court decisions that shaped OSHA's current regulatory 
framework, Appendix A to this Request for Information, History, Legal 
Background and Significant Court Decisions, provides additional 
information. Readers may want to consult Appendix A as they frame 
responses to the questions posed in this Request for Information.

IV. Reconsideration of Current Rulemaking Processes

    As reviewed in Section II (Legal Requirements for OSHA Standards) 
and Section III (History of OSHA's Efforts to Establish PELs), OSHA has 
to use the best available evidence to make findings of significant 
risk, substantial reductions in risk, and technological and economic 
feasibility under the Act. This section reviews how interpretation of 
6(b)(5) and subsequent case law has resulted in the methods it uses 
when developing risk, technical feasibility, and economic findings as 
well as the evidence OSHA has used in the past to make these findings 
(i.e., OSHA's use of

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formal risk assessment modeling to evaluate significant risk, and the 
Agency's use of worker exposure data and exposure control effectiveness 
data to evaluate technical feasibility and costs of compliance).
    This section also reviews developments in science and technology 
and how these new advancements may improve the scientific basis for 
making findings of significant risk, technical feasibility, and 
economic feasibility. As an example, the National Academies of Science 
has released extensive reviews of advances in science, toxicology, and 
risk and exposure assessment and evaluated how the Federal government 
can potentially utilize these advancements in its decision-making 
processes (NRC, 2012; Ex. #23, NRC, 2009; Ex. #24, NRC, 2007; Ex. #25). 
While new technologies will advance the public's understanding in these 
critical areas, the Agency has obligations under the OSH Act to make 
certain findings under 6(b)(5), as discussed above in Section III. How 
OSHA might utilize these new developments to meet the Agency's 
evidentiary burden will be discussed in this section.

A. Considerations for Risk Assessment Methods

1. Current Quantitative Risk Assessment Methods Typically Used by OSHA 
To Support 6(b) Single Substance Rulemaking
    As discussed in Section III, the Supreme Court requires OSHA to 
determine that a significant risk exists before adopting an 
occupational safety and health standard. While the Court did not 
stipulate a means to distinguish significant from insignificant risks, 
it broadly described the range of risks OSHA might determine to be 
significant:

    It is the Agency's responsibility to determine in the first 
instance what it considers to be a ``significant'' risk. Some risks 
are plainly acceptable and others are plainly unacceptable. If, for 
example, the odds are one in a billion that a person will die from 
cancer by taking a drink of chlorinated water, the risk clearly 
could not be considered significant. On the other hand, if the odds 
are one in a thousand that regular inhalation of gasoline vapors 
that are 2 percent benzene will be fatal, a reasonable person might 
well consider the risk significant and take the appropriate steps to 
decrease or eliminate it. (Benzene, 448 U.S. at 655). (Ex. #10),

    OSHA has interpreted the Court's example to mean that a 1 in 1000 
risk of serious illness is significant, and has used this measure to 
guide its significance of risk determinations. For example, OSHA's risk 
assessment for hexavalent chromium estimated that a 45-year 
occupational exposure at the PEL of 5[micro]g/m\3\ would lead to more 
than 10 lung cancer cases per 1000 workers exposed. Because this risk 
exceeds the value of one case of lung cancer per 1000 exposed workers, 
OSHA found it to be significant. The significance of risk 
determinations of other rules since the Benzene decision have typically 
followed a similar logic.
    Over the three decades since the Benzene decision, OSHA has 
gradually built up a highly rigorous approach to derive quantitative 
estimates of risk such as those found in the hexavalent chromium 
preamble. First, the Agency reviews the available exposure-response 
data for a chemical of interest. It evaluates the available data sets 
and identifies those best suited for quantitative analysis. Using the 
best available data, the Agency then conducts extensive statistical 
analyses to develop an exposure-response model that is able to 
extrapolate probability of disease at exposures below the observed 
data. Once the model is developed, OSHA conducts further analyses to 
evaluate the sensitivity of the model to error and uncertainties in the 
modeling inputs and approach. The exposure-response model is used to 
generate estimates of risk associated with a working lifetime of 
occupational exposure to the chemical of interest over a range of PEL 
options that often include exposure levels below those considered to be 
technologically feasible. The entire risk assessment has always been 
subject to peer review, from choice of data set(s) through generation 
of lifetime risk estimates.When the proposed rule is released for 
comment, it receives additional scrutiny from the scientific community, 
stakeholders, and the general public. The Agency uses the feedback of 
the peer review panel and public comment at the time of proposal to 
further test and develop the risk analysis.
    This model-based approach to risk assessment has a number of 
important advantages. The quantitative risk estimates can be easily 
compared with the level of 1 in 1000 that the Court cited as an example 
of significant risk. Sometimes, the best available data come from 
worker or animal populations with exposure levels far above the 
technologically feasible levels for which OSHA must evaluate risk, and 
a risk model is used to extrapolate from high to low exposures. When 
large, high-quality exposure-response data sets are available, a 
rigorous quantitative analysis can yield robust and fairly precise risk 
estimates to inform public understanding and debate about the health 
benefits of a new or revised regulation. However, there are also 
drawbacks to the model-based approach, and there are situations where a 
modeling analysis may not be necessary or appropriate for OSHA to make 
the significance of risk determination to support a new or revised 
regulation. Model-based risk analyses tend to require a great deal of 
Agency time and resources.
    In some cases, the model-based approach is essential to OSHA's 
significant risk determination, because it is not evident prior to a 
modeling analysis whether there is significant risk at current and 
technologically-feasible exposures. In other cases, however, it may be 
evident from the scientific literature or other readily available 
evidence that risk at the existing PEL is clearly significant and that 
it can be substantially reduced by a more stringent regulation without 
the need for quantitative estimates extrapolated from an exposure-
response model. In addition to reducing significant risk of harm, the 
OSH Act also directs the Agency to determine that health standards for 
toxic chemicals are feasible. At times, it is evident without extensive 
analysis that the most stringent PEL feasible can only reduce, not 
eliminate, significant risk. In such cases, the value of a model-based 
quantitative risk assessment may not warrant the Agency time and 
resources that model-based risk assessment requires.
    In situations described above where the PEL may be set at the 
lowest feasible level, OSHA believes that it can establish significant 
risk more efficiently instead of relying on probabilistic estimates 
from dose-response modeling as described above. OSHA is exploring a 
number of more flexible, scientifically accepted approaches that may 
streamline the risk assessment process and increase the capacity to 
address a greater number of chemicals.
    Question IV.A.1: OSHA seeks input on the risk assessment process 
described above. When is a model-based analysis necessary or 
appropriate to determine significance of risk and to select a new or 
revised PEL? When should simpler approaches be employed? Are there 
specific approaches OSHA should consider using when a model-based 
analysis is not required? To the extent possible, please provide 
detailed explanation and examples of situations when a model-based risk 
analysis is or is not necessary to determine significance of risk and 
to develop a new standard.

[[Page 61391]]

2. Proposed Tiered Approach to Risk Assessment in Support of Updating 
PELs for Chemical Substances
a. General Description and Rationale of Tiered Approach
    OSHA is considering a tiered process to exposure-response 
assessment that may enable the agency to more efficiently make the 
significant risk findings needed to establish acceptable PELs for 
larger numbers of workplace chemicals. The approach involves three 
stages: dose-response analysis in the observed range, margin of 
exposure determination, and exposure-response extrapolation (if 
needed). The process overlaps with the risk-based methodologies 
employed by EPA IRIS, NIOSH, the Agency for Toxic Substances Disease 
Registry (ATSDR), the European Union Registration, Evaluation, 
Authorization, and Restriction of Chemicals (REACH) program, and other 
organizations that recommend chemical toxicity values or exposure 
levels protective of human health. The first step is dose-response 
analysis in the observed range. During this step, OSHA analyzes 
exposures (or doses) and adverse outcomes from human studies or animal 
bioassays, particularly at the lower end of the exposure range. This 
involves the derivation of a ``low-end toxicity exposure'' (LETE), 
which is discussed further in section IV.A.2.c. below.
    The second step is margin of exposure determination, where LETEs 
are compared with the range of possible exposure limits that OSHA 
believes to be feasible for the new or proposed standard. Typically, 
there is a close and ongoing dialogue between those OSHA technical 
staff and management responsible for the risk assessment and their 
counterparts responsible for the feasibility analyses as the separate 
determinations are being simultaneously developed. Feasibility 
analyses, in particular, can take years of research, including site 
visits and industry surveys. In many of OSHA's rulemakings, the lowest 
feasible PEL can only reduce, not eliminate, significant risk. Thus, 
OSHA sets many PELs at the lowest feasible level, and not at a level of 
occupational exposure considered to be without significant risk. This 
significant risk orientation differs from other Federal Agencies, such 
as EPA and ATSDR that set environmental exposure levels determined to 
be health protective without consideration of feasibility.
    OSHA is considering using a margin of exposure (MOE) approach to 
compare the LETE with the range of feasible exposure limits. If the MOE 
indicates the range of feasible exposures is in close proximity to the 
exposures where toxicity is observed (i.e., a low MOE) then it may not 
be necessary to extrapolate exposure-response below the observed range 
in order to establish significant risk. In this situation, OSHA would 
set the PEL at the exposure level it determines to be feasible and the 
dose-response analysis in the observed range should be sufficient to 
support Agency significant risk findings. The PEL is set at the lowest 
feasible level, with the understanding that significant risk of adverse 
health outcomes remains at the new PEL. In the traditional risk 
assessment approach described previously, OSHA uses quantitative 
exposure-response modeling to estimate risks below the range of 
observed exposure, without regard to whether such exposures are 
considered to be technologically feasible. If the lowest 
technologically feasible workplace exposures are determined to be far 
below the LETE (i.e., a high MOE), an exposure-response model would be 
needed to determine significant risk at exposures below the observed 
range and to set the appropriate PEL.
    If there is a high MOE, then the Agency would move onto the final 
stage of the tiered approach, which is exposure-response extrapolation, 
where the dose-response relationship is extrapolated outside the 
observed range. Many regulatory agencies, such as EPA, choose to 
extrapolate outside the observed range for non-cancer health outcomes 
by applying a series of extrapolation factors, also called uncertainty 
factors, to an observed low-end toxicity value, referred to as a point 
of departure (POD). The POD is very similar to the LETE described 
above. The distinction between these toxicity values is discussed later 
in the subsection. The extrapolation factors are further explained 
below.
    In many instances, EPA does not use the extrapolation factor 
approach for cancer effects. Rather, EPA uses dose-response modeling in 
the observed range and a linear extrapolation below the observed range 
to derive a unit risk (i.e., risk per unit of exposure). As described 
previously, OSHA also uses dose-response modeling to extrapolate risk 
below the observed range for carcinogens as was done for hexavalent 
chromium (71 FR 10174-10221; Ex. #26) and methylene chloride (62 FR 
1516-1560; Ex. #27). There is a reasonable body of scientific evidence 
that genotoxic carcinogens, and perhaps other carcinogenic modes of 
action, display linear, non-threshold behavior at very low dose levels. 
OSHA also uses dose-response modeling to extrapolate risk below the 
observed range for carcinogens. As mentioned earlier, the Agency 
develops appropriate exposure-response models (linear or non-linear) 
that best fit the existing data and are consistent with available 
information on mode of action. The models can be used to extrapolate 
risk associated with a working lifetime at occupational exposures below 
the observed range.
    In some situations, the LETE is further adjusted to calculate 
worker equivalent exposures and to account for how the chemical is 
absorbed, distributed, and metabolized, and interacts with target 
tissues in the body. These features and other important issues related 
to the tiered approach to exposure-response assessment are discussed 
below. OSHA believes that there are a number of potential advantages to 
using a tiered risk assessment framework including opportunities to 
rely more heavily on peer-reviewed risk assessments already prepared by 
other Federal agencies.
b. Hazard Identification and Dose-Response Analysis in the Observed 
Range
    Hazard identification is the first step in the Federal risk 
assessment framework as laid out by the National Research Council's 
`red book' in 1983 (NRC, 1983; Ex. #28). In conducting a hazard 
identification, OSHA evaluates individual study quality and determines 
the weight of evidence from epidemiological, experimental, and 
supporting data. Study quality favors strong methodology, 
characterization of exposure during critical periods, adequate sample 
size/statistical power, and relevance to the workplace population. OSHA 
gives weight to both positive and negative studies according to study 
quality when the Agency evaluates the association between chemical 
agent and an adverse health effect. OSHA determines causality based on 
criteria developed by Bradford Hill (Hill, 1965; Ex. #29, Rothman & 
Greenland, 1998; Ex. #30). In its review of the available evidence, 
OSHA assesses the chemical's modes of action (MOA) and the key 
molecular, biological, pathological, and clinical endpoints that 
contribute to the health effects of concern.
    The Mode of Action (MOA) is a sequence of key events and processes 
starting with the interaction of the agent with a molecular or cellular 
target(s) and proceeding through operational and anatomical changes 
that result in an adverse health effect(s) of concern. The key events 
are empirically measurable molecular or pathological endpoints and 
outcomes in experimental systems. These represent necessary precursor

[[Page 61392]]

steps or biologically-based markers along the progression to frank 
illness and injury.
    MOA informs selection of appropriate toxicity-related endpoints and 
models for dose-response analysis. OSHA then conducts a dose-response 
analysis for critical health effects determined to be associated with a 
chemical, provided there are suitable data available. Dose-response 
analysis requires quantitative measures of both exposure and toxicity-
related endpoints. OSHA gives preference to studies with relevant 
occupational routes that display a well-defined dose-related change in 
response with adequate power to detect effects at the exposure levels 
of interest. The Agency generally prefers high quality epidemiologic 
studies for dose-response analysis over experimental animal models, 
provided there is adequate exposure information and confounding factors 
are appropriately controlled. OSHA may only adopt standards for 
exposure to ``toxic materials and harmful physical agents'' that causes 
``material impairment of health and loss of functional capacity even if 
such employee has regular exposure to the hazard dealt with by such 
standard for the period of his working life.'' OSH Act Sec.  6(b)(5) 
(Ex. #9) Therefore, its dose-response analysis considers those 
biological endpoints and health outcomes that can lead to adverse 
physiological or clinical harm caused by continued exposure over a 
working lifetime. This includes key molecular and cellular biomarkers 
established as necessary precursor events along a critical disease 
pathway. It is important that the toxicity-related endpoints observed 
in experimental animals selected for dose-response analysis have 
relevance to humans and are not unique to the test species.
    In the past, OSHA, for the most part, has undertaken an independent 
evaluation of the evidence in its identification of hazards and 
selection of critical studies and toxicity-related endpoints for dose-
response analysis. However, other Federal agencies use the same risk 
assessment framework with similar hazard identification and dose-
response selection procedures. EPA, ATSDR, NIOSH and others have active 
risk assessment programs and have recently evaluated many chemicals of 
interest to OSHA. These assessments undergo scientific peer review and 
are subject to public comment. The Agency is considering ways to reduce 
the time and resources needed to independently evaluate the available 
study data by placing greater reliance on the efforts of other credible 
scientific organizations. Although some organizations use their study 
evaluations to support non-occupational risk assessments, OSHA believes 
that, in most cases, these evaluations can be adapted to the 
occupational context.
    Question IV.A.2: If there is no OSHA PEL for a particular substance 
used in your facility, does your company/firm develop and/or use 
internal occupational exposure limits (OELs)? If so, what is the basis 
and process for establishing the OEL? Do you use an authoritative 
source, or do you conduct a risk assessment? If so, what sources and 
risk assessment approaches are applied? What criteria do facilities/
firms consider when deciding which authoritative source to use? For 
example, is rigorous scientific peer review of the OEL an important 
factor? Is transparency of how the OEL was developed important?
    Question IV.A.3: OSHA is considering greater reliance on peer-
reviewed toxicological evaluations by other Federal agencies, such as 
NIOSH, EPA, ATSDR, NIEHS and NTP for hazard identification and dose-
response analysis in the observed range. What advantages and 
disadvantages would result from this approach and could it be used in 
support of the PEL update process?
c. Derivation of Low-End Toxicity Exposure (LETE)
    An important aspect of the dose-response analysis is the 
determination of exposures that can result in adverse outcomes of 
interest. For most studies, response rates ranging from 1 to 10 percent 
represent the low end of the observed range. Epidemiologic studies 
generally are larger and can show a lower observed response rate than 
animal studies, which typically have fewer test subjects. EPA, ATSDR 
and EU REACH also derive an estimated dose at the low end of the 
observed range (i.e., LETE) as part of their dose-response assessments. 
This dose is referred to as the POD (`point of departure') because it 
is used as a starting point for low dose extrapolation or the 
application of uncertainty factors as described above to derive 
toxicity values. EPA, ATSDR and EU REACH use the POD/extrapolation 
factor approach to determine Reference Concentrations (RfC), Minimal 
Risk Levels (MRL) and Derived No Effect Levels (DNELs), respectively. 
OSHA believes the LETE is an exposure where studies may have 
demonstrated significant risk. However, OSHA does not intend to use the 
LETE as the point of extrapolation for determining a ``safe'' exposure 
level in the manner used by the aforementioned agencies. OSHA may use 
the LETE in calculating an MOE to evaluate the need for low dose 
extrapolation as described in the next section.
    Traditionally, either the Lowest Observed Adverse Effect Level 
(LOAEL) or No Observed Adverse Effect Levels (NOAEL) has served as 
easily obtainable LETE descriptors. More recently, the Benchmark Dose 
(BMD) methodology has increasingly been applied to derive an LETE. The 
BMD approach uses a standard set of empirical models to determine the 
dose associated with a pre-selected benchmark response (BMR) level. An 
example is the dose associated with a 10 percent incidence (i.e., 
BMD10) and the statistical lower confidence limit (i.e., 
BMDL10). Selection of an appropriate BMR considers biologic 
as well as statistical factors and a lower BMR is typically applied for 
clinically serious outcomes (e.g., lung or heart disease) than for less 
serious adverse effects (e.g., preclinical loss of neurological or 
pulmonary function). In some cases, more sophisticated models can be 
used in the LETE determination, based on physiologically-based 
toxicokinetics, toxicodynamics, or dosimetry models that relate the 
administered dose to a more toxicologically relevant dose metric at a 
biological target site, if sufficient data is available and the models 
are appropriately validated. This is discussed further below.
    Question IV.A.4: OSHA is considering using the Point of Departure 
(POD) (e.g., BMD, LOAEL, NOAEL), commonly employed by other 
authoritative organizations for carrying out non-cancer risk 
assessments as a suitable descriptor of the Low End Toxicity Exposure 
(LETE) level that represents a significant risk of harm. Is this an 
appropriate application of the POD by OSHA? Are there other exposure 
values that OSHA should consider for its LETE?
    In many situations, the LETE must be adjusted to represent a 
typical worker exposure. The most common adjustments are to correct for 
the standard occupational exposure conditions of eight hours a day/five 
days a week and/or respiratory volume during work activity. OSHA and 
NIOSH have used a standard ventilation rate of 10 m\3\ of air per 8-
hour work shift for a typical worker undergoing light physical work 
activity.
    Allometric scaling (i.e., BW3/4) is recommended by some 
Federal authorities when scaling animal doses to human equivalents to 
account for toxicokinetic differences in rates of absorption, 
metabolism, and excretion when more specific data is lacking. 
Allometric scaling refers to scaling

[[Page 61393]]

physiological rates and quantities to mass or volume of one animal 
species to another animal species. The relationship is generally 
dependent on body weight (BW), often in the form of 
y=BW[agr] where y is the physiological measure and [alpha] 
is the scaling component. Many physiological and biochemical processes 
(such as heart rate, basal metabolic rate, and respiration rate have 
been found to have a scaling component of 0.75.
    Allometric scaling is most applicable when the toxicologically 
relevant dose is a parent compound or stable metabolite whose 
absorption rate and clearance from the target site is controlled 
primarily by first order processes. Allometric scaling is less well 
suited for portal-of-entry effects or when toxicity is a consequence of 
a highly reactive compound or metabolite. Portal of entry refers to the 
tissue or organ of first contact between the biological system and the 
agent. This is nasal, respiratory tract and pulmonary tissues for 
inhalation; skin for dermal contact, and mouth and digestive tract for 
oral exposure.
    In the case of respiratory tract effects from inhalation, EPA 
recommends adjusting inhalation doses based on generic dosimetry 
modeling that depends on the form of the chemical (e.g., particle of 
gas) and site of toxicity (e.g., portal of entry or systemic) (EPA, 
1994; Ex. #31). For example, the human equivalent for a reactive gas 
that exerts its toxic effect on the respiratory tract is scaled based 
on animal to human differences in ventilation rate and regional surface 
area of the respiratory tract. On the other hand, the dosimetry model 
adjustment for an insoluble gas that exerts its effect in a tissue 
remote from the lung is scaled by species differences in the blood: gas 
partition coefficient. The generic dosimetry models can accommodate 
specific chemical data, if available. The models are only intended to 
account for human-to-animal differences in bioavailability and further 
allometric or extrapolation factors may be needed to account for 
species differences in metabolic activation and toxicodynamics (i.e., 
target site sensitivity to an equivalent delivered dose).
    Question IV.A.5: Several methodologies have been utilized to adjust 
critical study exposures to a worker equivalent under representative 
occupational exposure conditions including standard ventilation rates, 
allometric scaling, and toxicokinetic modeling. What are reasonable and 
acceptable methods to determine worker equivalent exposure 
concentrations, especially from studies in animals or other 
experimental systems?
    The worker-adjusted LETE that is derived from dose-response 
analysis in the observed range should be regarded as a chemical 
exposure level that leads to significant risk of harm. In most cases, 
the LETE is expected to elicit a toxic response in 1 to 10 percent of 
the worker population. This approximates an excess risk of 10 to 100 
cases of impairment per 1000 exposed workers over a duration that is 
typically less than a 45-year working life. This degree of risk would 
exceed the 1 per 1000 probability that OSHA historically regards as a 
clearly significant risk.
d. Margin of Exposure (MOE) as a Decision Tool for Low Dose 
Extrapolation
    As discussed previously, OSHA's statutory and legal obligations 
dictate that PELs be set at the level that eliminates significant risk, 
if feasible, or if not, at the lowest feasible level. Therefore, Agency 
risk assessments are directed at determining significant risk at these 
feasible exposures. Because of the feasibility constraints, low dose 
extrapolation is not always needed to make the required risk findings. 
The OSHA significant risk orientation differs from other Federal 
Agencies, such as EPA and ATSDR. The risk-based EPA RfCs and ATSDR MRLs 
are intended as environmental exposure levels determined to be health 
protective without consideration of feasibility. NIOSH also develops 
workplace exposure limits. These recommended exposure limits (RELs) are 
based on risk evaluations using human or animal health effects data. 
The exposure levels that can be achieved by engineering controls and 
measured by analytical techniques are considered in the development of 
RELs, but the recommended levels are often below what OSHA regards as 
technologically feasible.
    A MOE approach can assist in determining the need to extrapolate 
risk below the observed range. The appropriate MOE for use as a 
decision tool for low dose extrapolation is the LETE divided by an 
estimate of the lowest technologically feasible exposure (LTFE). A 
large MOE (i.e., LETE/LTFE ratio) means the LTFE is considerably below 
exposures observed to cause adverse outcomes along a critical toxicity 
pathway. This situation would require low-dose risk extrapolation to 
determine whether technologically feasible exposures lead to 
significant risk. A small MOE means the LTFE estimate is reasonably 
close to the observed toxic exposures indicating the LTFE likely leads 
to significant risk of harm. In this situation, OSHA would set the PEL 
at the exposure level it determines to be feasible and the dose-
response analysis in the observed range should be sufficient to support 
Agency significant risk findings.
    There are several factors that OSHA would need to consider in order 
to find that the MOE is adequate to avoid low-dose risk extrapolation. 
These include the nature of the adverse outcome, the magnitude of the 
effect, the methodological designs and experimental models of the 
selected studies, the exposure metric associated with the outcome, and 
the exposure period over which the outcome was studied. OSHA may regard 
a larger MOE as acceptable to avoid the need for low-dose extrapolation 
for serious clinical effects than a less serious subclinical outcome. A 
larger MOE may also be found acceptable for irreversible health 
outcomes that continue to progress with continued exposure and respond 
poorly to treatment than reversible health outcomes that do not 
progress with further exposure. Health outcomes that relate to 
cumulative exposures would tolerate higher MOEs than similar outcomes 
unrelated to cumulative exposure, especially in short-term studies. In 
some instances, an adverse outcome observed in experimental animals 
would tolerate higher MOEs than the same response in a human study that 
more closely resembles the occupational situation.
    Other Federal agencies apply the MOE approach as part of the risk 
assessment process. EPA has included MOE calculations in risk 
characterizations of environmental exposure scenarios to assist in risk 
management decisions (EPA, 2005; Ex. #32). The EU has also applied a 
very similar Margin of Safety analysis to characterize results of risk 
assessment conclusions (ECB, 2003; Ex. #33). In its report on the 
appropriate uses of risk assessment and risk management in federal 
regulatory programs, the Presidential Commission on Risk Assessment and 
Risk Management recommended MOE as an approach that provides a common 
metric for comparing health risks across different toxicities and 
public health programs (PCRARM, 1997; Ex. #34).
    Question IV.A.6: OSHA is considering a Margin of Exposure approach 
that compares the LETE with the Lowest Technologically Feasible 
Exposure (LTFE) as a decision tool for low dose extrapolation. Is this 
a reasonable means of determining if further low dose extrapolation 
methods are needed to meet agency significant risk findings?

[[Page 61394]]

What other approaches should be considered?
e. Extrapolation Below the Observed Range
    The last step in the tiered approach is extrapolation of risk below 
the observed range. This low-dose extrapolation would only be needed if 
the MOE is sufficiently high to warrant further dose-response analysis. 
This situation occurs when technologically feasible exposures are far 
below the LETE and quantitative estimates of risk could be highly 
informative in the determination of significant risk. As described in 
subsection A.1, OSHA has historically used probabilistic risk modeling 
to quantitatively estimate risks at exposure levels below the observed 
range. Depending on the nature of the exposure-response data, the 
Agency has relied on a wide range of different models that have 
included linear relative risk (e.g., hexavalent chromium/lung cancer), 
logistic regression (e.g., cadmium/kidney dysfunction), and 
physiologically-based pharmacokinetic (e.g., methylene chloride/cancer) 
approaches.
    Probabilistic risk models can require considerable time and 
resources to construct, parameterize, and statistically verify against 
appropriate study data, especially for a large number of chemical 
substances. As mentioned previously, several government authorities 
responsible for managing the risk to human populations posed by 
hazardous chemicals commonly use the computationally less complex 
uncertainty factor approach to extrapolate dose-response below the 
observed range. The uncertainty factors account for variability in 
response within the human population, uncertainty with regard to the 
differences between experimental animals and humans, and uncertainty 
associated with various other data inferences made in the assessment. 
For each of these considerations, a numerical value is assigned and the 
point of departure is divided by the product of all applied uncertainty 
factors. The result is an exposure level considered to be without 
appreciable risk. OSHA attempted to apply uncertainty factors in the 
1989 Air Contaminants Rule to ensure that new PELs were set at levels 
that were sufficiently below exposures observed to cause health 
effects. The Eleventh Circuit ruled that OSHA had failed to show how 
uncertainty factors addressed the extent of risk posed by individual 
substances and that similarly, OSHA failed to explain the method it 
used to derive the safety factors. Air Contaminants 965 F.2d at 978.( 
Ex. #8) Since the court ruling, the uncertainty factor approach has 
undergone considerable refinement. The scientific considerations for 
applying individual factors have been carefully articulated by EPA and 
other scientific authorities in various guidance materials (EPA, 2002; 
Ex. #35, IPCS, 2005; Ex. #36, ECHA, 2012a; Ex. #37). For some factors 
under certain circumstances, it is being proposed that standard 
`default' values can be replaced with `data-driven' values (EPA, 2011; 
Ex. #38). However, the type and magnitude of the uncertainty factor 
employed for any individual substance still requires a degree of 
scientific judgment. The methodology does not provide quantitative 
exposure-specific estimates of risk, such as one in a thousand, that 
can readily be compared to the significant risk probabilities discussed 
in the Benzene decision.
    The National Research Council's Science and Decisions report 
recently advocated a dose-response framework that provides quantitative 
risk estimates by applying distributions instead of `single value' 
factors (NRC, 2009; Ex. #24). The critical extrapolation factors, such 
as species differences in toxic response at equivalent target doses and 
inter-individual variability in the human population are defined by 
lognormal distribution with an estimated standard deviation. This 
allows the human equivalent LETE to be derived in terms of a median and 
statistical lower confidence bound. The distributional nature of the 
analysis facilitates extrapolation in terms of a probabilistic 
projection of average and upper bound risk at specific exposures, such 
as X number of individuals projected to develop disease out of 1000 
workers exposed to Z level of a toxic substance within some confidence 
level Y. The NRC report describes several different conceptual models 
with case examples and extrapolation factor distribution calculations 
(NRC, 2009; Ex. #24).
    Question IV.A.7: Can the uncertainty factor methodology for 
extrapolating below the observed range for non-cancer effects be 
successfully adapted by OSHA to streamline its risk assessment process 
for the purpose of setting updated PELs? Why or why not? Are there 
advantages and disadvantages to applying extrapolation factor 
distributions rather than single uncertainty factor values? Please 
explain your reasoning.
3. Chemical Grouping for Risk Assessment
    OSHA is also considering the use of one or more chemical grouping 
approaches to expedite the risk assessment process. In certain cases, 
it may be appropriate to extrapolate data about one chemical across a 
group or category of similar chemicals. These approaches are discussed 
below.
a. Background on Chemical Grouping
    The term `grouping' or `chemical grouping' describes the general 
approach to assessing more than one chemical at the same time. It can 
include formation of a chemical category or identification of a 
chemical analogue (OECD, 2007; Ex. #39). Chemical categories or 
analogues can be based on the structural relationship between the 
chemicals being grouped.
    Structure-activity relationships (SAR) are relationships between a 
compound's chemical structure and physicochemical properties and its 
biological effects (e.g., cancer) on living systems. Structurally 
diverse chemicals can sometimes be grouped for risk analysis based on a 
common mechanism/mode of action or metabolic activation pathway (i.e., 
mechanism/mode of action clustering). Endpoint information for one 
chemical is used to predict the same endpoint for another chemical, 
which is considered to be ``similar'' in some way (usually on the basis 
of structural similarity and similar properties and/or activities).
    A chemical category is a group of chemicals whose physical-
chemical, human health, environmental, toxicological, and/or 
environmental fate properties are likely to be similar or follow a 
regular pattern as a result of structural similarity, structural 
relationship, or other characteristic(s). A chemical category is 
selected based on the hypothesis that the properties of a series of 
chemicals with common features will show coherent trends in their 
physical-chemical properties, and more importantly, in their 
toxicological effects (OECD, 2007; Ex. #39).
    The use of a category approach means that it is possible to 
identify chemical properties which are common to at least some members 
of the category. This approach provides a basis for establishing trends 
in properties across that category and extends the measured data (e.g., 
toxicological endpoint) to similar untested chemicals.
    In the category approach, not every chemical in a group needs to 
have exposure-response data in order to be evaluated. Rather, the 
overall data for the category as a whole must prove adequate to support 
a risk assessment.

[[Page 61395]]

The overall data set must allow for an assessment of risk for the 
compounds and adverse outcomes that lack adequate study. Chemicals may 
be grouped for risk assessment based on the following:
     Common functional group (e.g., aldehyde, epoxide, ester, 
specific metal ion);
     Common constituents or chemical classes, similar carbon 
range numbers;
     Incremental and constant change across the category (e.g., 
a chain-length category);
     The likelihood of common precursors and/or breakdown 
products, via physical or biological processes, which result in 
structurally similar chemicals (e.g., the metabolic pathway approach of 
examining related chemicals such as acid/ester/salt).
    Within a chemical category, data gaps may be filled by read-across, 
trend analysis and Quantitative Structure-Activity Relationships 
(QSARs) and threshold of toxicological concern. In some cases, an 
effect can be present for some but not all members of the category. An 
example is the glycol ethers, where the lower carbon chain length 
members of the category indicate reproductive toxicity but the higher 
carbon chain length members of the category do not. In other cases, the 
category may show a consistent trend where the resulting potencies lead 
to different classifications (OECD, 2007; Ex. #39).
b. Methods of Gap Analysis and Filling
    As a result of grouping chemicals based on similarities determined 
when employing the various techniques as described above, data gap 
filling in a chemical category can be carried out by applying one or 
more of the following procedures: read-across, trend analysis, 
quantitative (Q)SARs and threshold of toxicological concern (TTC).
i. Read-Across Method
    The read-across approach uses endpoint information for one chemical 
(the source chemical) to predict the same endpoint for another chemical 
(the target chemical), which is considered to be ``similar'' in some 
way (usually on the basis of structural similarity or on the basis of 
the same mode or mechanisms of action). Read-across methods have been 
used to assess physicochemical properties and toxicity in a qualitative 
or quantitative manner. The main application for qualitative read-
across is in hazard identification.
ii. Trend Analysis
    Chemical category members are often related by a trend (e.g., 
increasing, decreasing or constant) for any specific endpoint. The 
relationship of the categorical trend could be molecular mass, carbon 
chain length, or to some other physicochemical property.
    The observation of a trend (increasing, decreasing or constant) in 
the experimental data for a given endpoint across chemicals can be used 
as the basis for interpolation and possibly also extrapolation to fill 
data gaps for chemicals with little to no data. Interpolation is the 
estimation of a value for a member using measured values from other 
members on ``both sides'' of that member within the defined category 
spectrum, whereas extrapolation refers to the estimation of a value for 
a member that is near or at the category boundary using measured values 
from internal category members (OECD, 2007; Ex. #39).
iii. QSAR
    A Quantitative Structure-Activity Relationship (QSAR) is a 
quantitative relationship between a numerical measure of chemical 
structure, and/or a physicochemical property, and an effect/activity. 
QSARs use mathematical calculations to make predictions of effects/
activities that are either on a continuous scale or on a categorical 
scale. ``Quantitative'' refers to the nature of the relationship 
between structurally related chemicals, not the endpoint being 
predicted. Most often QSARs have been used for determining aquatic 
toxicity or genotoxicity but can be used for evaluating other endpoints 
as well (OECD, 2007; Ex. #39).
    Question IV.A.8: Are QSAR, read-across, and trend analysis 
acceptable methods for developing risk assessments for a category of 
chemicals with similar structural alerts (chemical groupings known to 
be associated with a particular type of toxic effect, e.g., 
mutagenicity) or other toxicologically-relevant physiochemical 
attributes? Why or why not? Are there other suitable approaches?
iv. Threshold of Toxicological Concern (TTC)
    The Threshold of Toxicological Concern (TTC) refers to the 
establishment of an exposure level for a group of chemicals below which 
there would be no appreciable risk to human health. The original 
concept proposed that a low level of exposure with a negligible risk 
can be identified for many chemicals, including those of unknown 
toxicity, based on knowledge of their chemical structures. The TTC 
approach is a form of risk characterization in which uncertainties 
arising from the use of data on other compounds are balanced against 
the low level of exposure. The approach was initially developed by the 
FDA for migration of chemicals from consumer packaging into food 
products and used a single threshold value of 1.5[micro]g/day (referred 
to as the threshold of regulation).
    The TTC principle extends the concept used in setting acceptable 
daily allowable intakes (ADIs) by proposing that a de minimis value can 
be identified for chemicals with little to no toxicity data utilizing 
information from structurally related chemicals with known toxicities.
    A decision tree can be developed to apply the TTC principle for 
risk assessment decisions:

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[GRAPHIC] [TIFF OMITTED] TP10OC14.000

    For OSHA purposes the TTC approach could be adapted to develop an 
endpoint-specific LETE value for chemicals in a specific category where 
little to no toxicity data exist utilizing source chemicals within the 
category where toxicity data is available.
4. Use of Systems Biology and Other Emerging Test Data in Risk 
Assessment
    Toxicity testing is undergoing transformation from an approach 
primarily based on pathological outcomes in experimental animal studies 
to a more predictive paradigm that characterizes critical molecular/
cellular perturbations in toxicity pathways using in vitro test 
systems. The paradigm shift is being largely driven by the 
technological advances in molecular systems biology such as the use of 
high throughput screening (HTS) assays, new computational methods to 
predict chemical properties, and computer models able to associate 
molecular events with a biological response. The vision, strategies, 
and frameworks for applying the new toxicity data to risk-based 
decision making are laid out in landmark reports by the National 
Research Council (NRC, 2009; Ex. #24, NRC, 2007; Ex. #25). A 
collaborative Federal initiative known as ``Tox21'' has been 
established between the National Toxicology Program (NTP), the EPA 
Office of Research and Development, the NIH Chemical Genomics Center 
(NCGC), and the Food and Drug Administration (FDA) to collaborate on 
development, validation, and translation of innovative HTS methods to 
characterize key steps in toxicity pathways (NTP, 2013; Ex. #40). Tox21 
has already screened over a 1000 compounds in more than 50 quantitative 
HTS assays that have been made available to the scientific community 
through publically accessible databases (e.g., EPA ACToR, NTP CEBS). 
EPA has launched a program, known as ``NexGen'', to implement the NRC 
vision and advance the next generation of risk assessment (EPA, 2013b; 
Ex. #41). NexGen is a partnership among EPA, NTP, NCGC, AND FDA, along 
with ATSDR and California's EPA Office of Environmental Health Hazard 
Assessment. The objectives of NexGen are to pilot the new NRC risk 
assessment framework, refine existing bioinformatics systems, and 
develop specific prototype health risk assessments. These objectives 
are expected to be achieved through an iterative development process 
that includes discussion with scientists, risk managers, and 
stakeholders.
    Question IV.A.9: How should OSHA utilize the new molecular-based 
toxicity data, high throughput and computer-based computational 
approaches being generated on many workplace chemicals and the updated 
NRC risk-based decision making framework to inform future Agency risk 
assessments?

B. Considerations for Technological Feasibility

    Before adopting a particular regulatory alternative, the Agency 
must demonstrate that it is technologically feasible. As OSHA currently 
performs it, a technological feasibility analysis is often one of the 
most resource-intensive

[[Page 61397]]

aspects of the rulemaking process. The Agency must identify all of the 
industries that are potentially affected and compile the available 
information on current worker exposure and existing controls for each 
industry. On occasion, the best information available for technological 
feasibility analyses comes from sparse and incomplete data sets. Rather 
than rely exclusively on such variable information, OSHA is considering 
the use of exposure modeling, such as computational fluid dynamics 
(CFD) modeling, for a more complete picture of worker exposures and the 
potential effectiveness of different control strategies. Additionally, 
OSHA is looking at other sources of information, such as the REACH 
initiative from the European Union, that may help the Agency to better 
characterize industries or jobs where there is little to no data on 
worker exposures and control technologies.
1. Legal Background of Technological Feasibility
    OSHA must demonstrate that a PEL, as well as any ancillary 
provisions, to the extend they are being adopted, are feasible. In 
general, OSHA determines that a regulatory alternative is 
technologically feasible when it has evidence that demonstrates the 
alternative is achievable in most operations most of the time. The 
Agency must also show that sampling and analytical methods can measure 
exposures at the proposed PEL within an acceptable degree of accuracy. 
OSHA makes these determinations in the technological feasibility 
analysis, which is made available to the public in the OSHA rulemaking 
docket.
2. Current Methodology of the Technological Feasibility Requirement
    To develop its technological feasibility analysis, the Agency must 
first collect the information about the industries that are affected by 
a particular hazard, the sources of exposure, the frequency of the 
exposure, the number of workers exposed to various levels, what control 
measures or other efforts are being made to reduce exposure to the 
hazard, and what sampling and analytical methods are available.
    This information is typically obtained from numerous sources 
including:
     Published literature,
     OSHA Special Emphasis Program (SEP) reports,
     NIOSH reports, such as health hazard evaluations (HHE), 
control technology (CT) assessments, surveys, recommendations for 
exposure control, and engineering control feasibility studies,
     Site visits, conducted by OSHA, NIOSH, or supporting 
contractors,
     Information from other stakeholders, such as federal and 
state agencies, labor organizations, industry associations, and 
consensus standards,
     Unpublished information, such as personal communications, 
meetings, and presentations, and
     OSHA Integrated Management Information System (IMIS) data.
    With this information, OSHA creates profiles that identify the 
industries where exposures occur, what operations lead to exposures, 
and what engineering controls and work practices are being implemented 
to mitigate exposures. A technological feasibility analysis is 
typically organized by industry sector or group of sectors that 
performs a unique activity involving similar activities. OSHA 
identifies the operations that lead to exposures in all of these 
industries, and eventually determines the feasibility of a PEL by 
analyzing whether the PEL can be achieved in most operations most of 
the time, as an aggregate across all industries affected. OSHA has also 
utilized an application approach that evaluates the feasibility of 
controls for a specific type of process used across a number of 
industry sectors, such as welding, rather than on an industry-by-
industry basis.
    OSHA develops detailed descriptions of how the substance is used in 
different industries, the work activities during which workers are 
exposed, and the primary sources of exposure. The Agency also 
constructs exposure profiles for each industry, or by job category, 
based on operations performed. The Agency classifies workers by job 
categories within those industries, based on how similar work processes 
are, and to what extent similar engineering controls can be applied to 
control exposures in those processes.
    Each exposure profile contains a list of affected job categories, 
summary statistics for each job category and subcategories (such as the 
mean, median, and range of exposures), and the distribution of worker 
exposures using increments based on the regulatory alternatives.
    OSHA's technological feasibility analyses for PEL-setting standards 
have traditionally relied on full-shift, personal breathing zone (PBZ) 
samples to create exposure profiles. A PBZ sample is the best sample 
type to quantify the inhalation exposure of a worker. Area samples are 
typically not used to construct exposure profiles but are useful to 
characterize how much airborne contamination is present in a work 
environment and to evaluate the effectiveness of engineering and other 
process control measures.
    Exposure profiles are used to establish the baseline exposure 
conditions for every job category in affected industries. Baseline 
conditions are developed to allow the Agency to estimate the extent to 
which additional controls will be required to achieve a level specified 
by a regulatory alternative.
    Next, the technological feasibility analysis describes the 
additional controls necessary to achieve the regulatory alternatives. 
OSHA relies on its traditional hierarchy of controls when demonstrating 
the feasibility of control technology. The traditional hierarchy of 
controls includes, in order of preference: Substitution, local exhaust 
ventilation, dust suppression, process enclosures, work practices, and 
housekeeping. OSHA considers use of personal protective equipment, such 
as respirators, to be is the least effective method for controlling 
employee exposure, and therefore, personal protective equipment is 
considered only for limited situations in which all feasible 
engineering controls have been implemented, but do not effectively 
reduce exposure to below the permissible exposure limit. To identify 
what additional controls are feasible, the Agency conducts a detailed 
investigation of the controls used in different industries based 
primarily on case studies.
    OSHA develops preliminary conclusions regarding feasibility of 
regulatory alternatives, by identifying the lowest levels of exposure 
that are technologically feasible in workplaces. To determine whether 
an alternative is feasible throughout the spectrum of affected 
industries, OSHA studies whether the regulatory alternative is 
achievable in most operations most of the time by a typical firm. OSHA 
may also determine whether a specific process used across a number of 
different industries can be effectively controlled.
3. Role of Exposure Modeling in Technological Feasibility
    In many situations, the Agency has found it difficult to develop 
comprehensive exposure profiles and determine additional controls 
because of limitations associated with the available exposure data. 
These information gaps could be filled by incorporating exposure 
modeling into the technological feasibility process. The limitations 
associated with the data collected include:
     Limited number of exposure samples: On occasions, an 
exposure

[[Page 61398]]

profile for a job category may be built on a limited number of full-
shift exposure samples, and the Agency has to judge whether the samples 
available are representative of the actual exposure distribution for 
that industry.
     Limit of Detection (LOD) issues: Because only a few 
exposure samples may be available for a job category, the analysis may 
include samples reported as ``less than'' values, high LODs, or 
adjusted LOD values. This causes inconsistency in the use of LOD 
samples and may cause the Agency to under- or over-estimate the actual 
exposure distribution.
     Lack of information on controls associated with data: 
Information regarding working conditions and control strategies 
associated with exposure samples may not be available. This makes it 
difficult for the Agency to determine the impact of the control 
strategies for various sources of exposure. Additionally, it is common 
that the data does not include information about the exact nature of 
the task performed during the sampling period. Sometimes, samples may 
not exactly correspond to the job category to which OSHA assigns it in 
the analysis because the job activities performed are not adequately 
described.
     Limitations of traditional industrial hygiene sampling: 
Traditional industrial hygiene practices require a ``before and after'' 
data set to gauge the effectiveness of control strategies implemented, 
and changes that occur in the working environment during the sampling 
periods. The exact impact of control strategies and environmental 
conditions cannot be determined easily with only one set of samples 
obtained at a discrete moment in time. It is often the case that OSHA 
does not have the luxury of ``before and after'' data sets and must 
determine how the sample set fits into the exposure profile.
     IMIS data limitations: Since the Agency may lack exposure 
data for a particular job category or operation, it sometimes relies on 
IMIS data. OSHA does not usually rely on IMIS data in its exposure 
profiles unless there are no other exposure data available because the 
IMIS data can have some significant limitations, which include the 
following:
    [cir] Insufficient information to determine if a hazard is present 
in the work area in significant amounts as to be relevant for an 
exposure profile. For example, an analyst cannot tell from the 
information available in the IMIS database if a sample was targeted for 
the hazard in question, or if it was part of a larger metal screening 
process (if the hazard is a metal), which typically includes up to 16 
different metals whether they are thought to be present in the sampling 
environment or not.
    [cir] Use of SIC codes in historic IMIS data, which do not 
translate directly into the NAICS codes currently used in the analyses.
    [cir] There is no information in the database on the end product 
being developed, the action performed to produce it, or the materials 
being used when the sample is taken. This limits the interpretation of 
the data, since an analyst is not able to attribute the exposure to any 
particular practice or process, and cannot recommend engineering 
controls.
    Generally, OSHA has had the most success using IMIS data to 
identify and collect enforcement case files for further review. Case 
files from OSHA inspections contain more detailed information on worker 
activities and exposure controls observed at the time an exposure 
sample is taken. Thus, use of case files to a large extent mitigates 
the limitations of using IMIS data.
    For most health standards, OSHA does not have the resources to 
conduct site visits to obtain the necessary exposure information at 
firms that are representative of all the affected industries. In an 
effort to develop more robust exposure profiles, the Agency is 
considering the use of exposure modeling, such as computational fluid 
dynamics (CFD) modeling, to complement the exposure information that is 
already available from literature, site visits, NIOSH and similar field 
investigations, and employer-provided data. This technique would 
potentially allow OSHA to better estimate workplace exposures in those 
environments were data are limited.
    Question IV.B.1: OSHA described how it obtains information 
necessary to conduct its industry profiles. Are there additional or 
better sources of information on the industries where exposures are 
likely, the numbers of workers and current exposure levels that OSHA 
could use?
a. Computational Fluid Dynamics Modeling To Predict Workplace Exposures
    OSHA is considering the use of computational fluid dynamics (CFD) 
to model workplace exposure. CFD is a discipline of fluid mechanics 
that uses computer modeling to solve complex problems involving fluid 
flows. Fluid flow is the physical behavior of fluids, either liquids or 
gases, and it is represented by systems of partial differential 
equations that describe conservation of energy, mass, and momentum. For 
some physical phenomena, such as the laminar flow of a fluid through a 
cylindrical pipe, these equations can be solved mathematically. Such 
solutions describe how a fluid will move through the specified area, or 
geometry, as a function of time. For more complex physical phenomena, 
such as turbulent flow of a fluid through a complex geometry, numerical 
approaches are used to solve the governing differential equations. As 
such, CFD modeling uses mathematical models and numerical methods to 
determine how fluids will behave according to a particular set of 
variables and parameters. A mathematical model simulates the physical 
phenomena under consideration (i.e. governing equations of energy, 
mass, and momentum) and, in turn, a numerical method solves that model. 
Overall, CFD modeling enables scientists and engineers to perform 
computer simulations in order to make better qualitative and 
quantitative predictions of fluid flows.
    Some modeling techniques, such as CFD, allow a user to create a 
virtual geometry to simulate actual work environments using appropriate 
mathematical models and computational methods. The solutions predict 
exposures at any given time and in any point in the space of the 
geometry established. A model developed with this technique allows the 
user to evaluate exposures in a worker's personal breathing zone and 
identify areas in the work space that present high concentrations of 
the contaminant. Because the exposure concentration can be solved as a 
function of time, the user can observe how concentration increases or 
decreases with time or other changes in the model input parameters. 
This allows the user to consider administrative controls such as 
limiting the time of the operation, the quantity of material emitted by 
the process, or determining how long after an operation a worker can 
safely enter a previously contaminated area. In some cases, work tasks 
and processes that are time-varying can be communicated to the CFD 
model through time-varying boundary conditions.
    Models require a defined geometry (i.e., work space), and this step 
in the model building may be resource intensive. To construct 
geometries of complex work environments, OSHA would need to gather the 
necessary information to model the work environment. This includes 
taking measurements of the work area, machinery, engineering control 
specifications (e.g., exhaust face velocities, spray systems flow 
rates),

[[Page 61399]]

and any other objects or activities that may affect the air flow in the 
area of interest. Moreover, gathering site-specific information for 
building CFD models can be integrated with traditional industrial 
hygiene survey activities. OSHA is interested in identifying ways to 
reduce the time and money that may be spent recreating work 
environments. One alternative is to import facility layouts in an 
electronic format (such as CAD) into the modeling software. If an 
establishment has its facility layout in this format, then the model 
designer would not have to take physical measurements and recreate the 
work area by 3-D modeling.
    Question IV.B.2: In cases where there is no exposure information 
available, to what degree should OSHA rely on modeling results to 
develop exposure profiles and feasible control strategies? Please 
explain why or why not.
    Question IV.B.3: What partnerships should OSHA seek to obtain 
information required to most efficiently construct models of work 
environments? More specifically, how should OSHA select facility 
layouts to model that are representative of typical work environments 
in a particular industry? Note that the considerations should include 
variables such as work area dimensions, production volumes and 
ventilation rates in order to develop models for both large and small 
scale operations.
    Models must undergo validation and testing to determine if they 
provide an accurate prediction of the physical phenomenon under 
consideration, or in this case, the concentrations of air contaminants 
to which workers could be potentially exposed. Sensitivity analyses can 
be used to determine if model outputs are consistent given minor 
changes to grid cell size and time step duration. Grid cell size refers 
to the division of space according to nodes, and time step refers to 
the value attributed to the time variable to numerically solve the 
equations with reference to the nodes. Another method for model 
evaluation is the comparison between the solutions of different models 
to the same problem in that a similarity of findings across multiple 
CFD models would provide greater confidence in the results. Arguably, 
the best performance evaluation is the comparison of model results to 
those of a field experiment that simulates on different scales the 
actual work environment.
    This method of predicting workplace exposures has some potential 
advantages over traditional industrial hygiene sampling methods. 
Patankar (1980; Ex. #42) explains some of the advantages of theoretical 
calculations, in a general sense, to predict heat transfer and fluid 
flow processes. Some of these are:
     Low Cost: In many current and future applications, the 
cost of a computational method may be lower than the corresponding 
sampling cost. As mentioned above, the most resource-consuming aspect 
of solid modeling is simulating the geometry that resembles actual 
physical space of work environments.
     Speed: A numerical solution to predict exposures can be 
obtained very easily in a day. A user could manipulate different 
configurations regarding worker positioning and engineering controls to 
find an optimal control strategy.
     Complete information: A computer solution provides the 
values of all relevant variables throughout the domain of interest. 
These variables cover fluid flow patterns, areas in the geometry with 
highest concentrations of contamination, exposure values at any point 
in the geometry, time profile of contamination, and exposure results 
based on different control configurations. Traditional industrial 
hygiene sampling does not allow for this level of analysis as it 
measures results based on a particular work environment, and it cannot 
distinguish how each independent variable (e.g., changes in the 
workplace during sampling) affects the exposure result.
     Ability to simulate realistic conditions: A computer 
solution can accommodate any environmental condition and the values for 
all variables that affect the solution can be easily modified to fit a 
particular scenario.
    Patankar (1980; Ex. #42) also discusses the disadvantages of 
theoretical predictions to address heat transfer and fluid flow 
processes, and they are applicable to exposure modeling. The solutions 
obtained depend on the mathematical model used to simulate the 
situation, the value of the input parameters, and the numerical method 
used to obtain a solution. As Patankar notes, ``a perfectly 
satisfactory numerical technique can produce worthless results if an 
inadequate mathematical model is employed''. This is why it is 
imperative that the mathematical model chosen actually resembles the 
physical phenomena under consideration.
    The Agency also realizes that even if an appropriate mathematical 
model and numerical method are obtained to describe contamination in a 
workplace, the exposure modeling approach may prove to be more 
resource-intensive than traditional industrial hygiene sampling for 
work environments with complex geometries. In these situations, OSHA 
would have to develop a site visit protocol for gathering dimensions of 
the work environment of interest. The information to be collected 
includes the dimensions of the physical space, the ventilation system 
that affects airflow patterns, and other details (such as location and 
size of windows, doors, and large obstructions).
    Despite these limitations, modeling promises to provide significant 
advantages that could help OSHA construct more robust technological 
feasibility analyses while reducing the considerable amount of 
resources the Agency already expends on them. In addition to CFD 
modeling, the Agency will continue to investigate other exposure 
modeling techniques and their applicability in the rulemaking process.
    Question IV.B.4: Should OSHA use only models that have been 
validated? If so, what criteria for model validation should be 
employed?
    Question IV.B.5: What exposure models are you aware of that can be 
useful for predicting workplace exposures and help OSHA create exposure 
profiles and in what circumstances?
    At this time, OSHA is primarily examining the possibility of 
incorporating CFD models to indoor work operations. Most general 
industry and some construction operations are performed indoors. As the 
Agency conducts more research on the applicability of CFD models to 
predict workplace exposures, outdoor models will also be considered. As 
such, OSHA is interested in obtaining input from parties experienced in 
these models.
    Question IV.B.6: Should OSHA consider CFD models primarily for 
indoor operations, outdoor operations, or both? What limitations exist 
with these two different types of models?
    Various U.S. federal agencies have used CFD modeling for projects 
related to indoor air quality and/or occupational health and safety. 
Preliminary research indicates that this CFD modeling work has been 
performed mostly for academic and research purposes. There is little 
information available discussing the use of CFD modeling for the 
purposes of litigation and/or regulatory decision-making.
    NIOSH has used CFD on a variety of internal research initiatives 
that involve evaluating and controlling airborne exposures. Among other 
projects, NIOSH has used CFD modeling to:
     Evaluate potential exposure concentrations to hexavalent 
chromium (CrVI), hexamethylene diisocyanate

[[Page 61400]]

(HDI), methyl isobutyl ketone (MIBK), and others with different 
ventilation control configurations during spray painting operations at 
a Navy aircraft paint hangar. In this study, NIOSH also tested and 
validated the predictive value of CFD modelling against methods of 
physical sampling by conducting workplace air sampling and comparing 
with model results. The project was performed with assistance from the 
Naval Facilities Engineering Command (NAVFAC) and the Navy Medical 
Center San Diego (NMCSD) (NIOSH, 2011a; Ex. #43),
     Study the effectiveness of ventilation systems for 
controlling Tuberculosis (NIOSH, 2010; Ex. #44),
     Evaluate emission controls for mail processing and 
handling facilities (NIOSH, 2010; Ex. #44),
     Better understand the role airflow and ventilation play in 
disease transmission in commercial aircraft cabins (NIOSH, 2010; Ex. 
#44),
     Simulate different air sampling methods to better 
understand how sampling methods can assess exposure (NIOSH, 2010; Ex. 
#44), and
     Help better understand the effectiveness of various forms 
of exposure control technologies in the manufacturing and 
transportation, warehousing, and utilities in the National Occupational 
Research Agenda (NORA) Sectors (NIOSH, 2011b; Ex. #45).
    Additionally, NIOSH has also used CFD models in mine safety 
research:
     NIOSH conducted a CFD study to model the potential for 
spontaneous heating in particular areas of underground coal mines 
(Yuan, L. et al., 2006;  Ex. #46). The purpose of the study was to 
provide insights into the optimization of ventilation systems for 
underground coal mines that face both methane control and spontaneous 
combustion issues.
     NIOSH looked at the rate of flame spread along combustible 
materials in a ventilated underground mine entry. CFD models were used 
to estimate the flame spreading rates of a mine fire (Edwards, J. C., 
and Hwang, C. C., 2006;  Ex. #47).
     NIOSH has also used CFD modeling to model inert gas 
injection and oxygen depletion in sealed areas of underground mines 
(Trevits, M. A., et al., 2010; ; Ex. #48). CFD simulations were created 
to model inert gas injections that aim to eliminate explosive 
atmospheres that form in sealed mine areas. The CFD model was able to 
quantify oxygen depletion and gas leakage rates of the sealed area.
    EPA has conducted a substantial amount of work using CFD modeling 
to assess outdoor air quality. However there is little information 
available on EPA projects that have used CFD to evaluate indoor air 
quality.
    As part of the Labs21 program, EPA, in conjunction with the 
Department of Energy, has published a guidance document for 
optimization of laboratory ventilation rates (EPA & DOE, 2008; Ex #49). 
The guidance is geared towards architects, engineers, and facilities 
managers, in order to provide information about technologies and 
practices to use in designing, constructing, and operating safe, 
sustainable, high-performance laboratories. EPA advocates the use of 
CFD simulations to determine the airflow characteristics of a 
laboratory space in order to improve ventilation systems and increase 
safety and energy efficiency.
    The Building and Fire Research Laboratory of National Institute of 
Standards and Technology (NIST) developed a CFD model to simulate the 
transport of smoke and hot gases during a fire in an enclosed space 
(NIST, 1997; Ex. #50). The results of the study and an extensive 
literature review indicated to NIST that CFD can have significant 
benefits in the study of indoor air quality and ventilation. The report 
resulting from this study provides a thorough description of CFD and 
provides recommendations for future directions in CFD research.
    The Building and Fire Research Laboratory of NIST has also used CFD 
to model the effects of outdoor gas generator use on the air 
concentrations of carbon monoxide inside nearby buildings (NIST, 2009; 
Ex. #51). Using CONTAM (a mathematical indoor air quality model), 
coupled with CFD simulations, the researchers were able to determine 
factors (e.g., generator positioning, wind direction) that contributed 
to elevated carbon monoxide accumulation in the building.
    As OSHA continues to explore the option of incorporating CFD 
modeling into its technological feasibility analyses, the Agency will 
conduct further research on existing models.
b. The Potential Role of REACH in Technological Feasibility
    Similar to the evaluation of chemical substances by the European 
Chemicals Agency (ECHA) and the European Commission before making a 
decision to ban or restrict the use of a substance, OSHA must evaluate 
information on health effects, exposure levels, and existing controls 
before setting a new or revised PEL. However, ECHA requires chemical 
manufacturers to generate the information evaluated by government 
decision-makers, while in the U.S., OSHA itself is responsible for 
generating, researching, and evaluating the relevant information.
    As explained in more detail above, OSHA creates industry profiles 
to evaluate the technological feasibility of a standard. The objective 
of these profiles is to estimate the number of workers potentially 
exposed to occupational hazards. OSHA relies on information from 
numerous sources including the U.S. EPA, U.S. DOL, U.S. Census Bureau, 
NIOSH, scientific publications, and site visits to identify specific 
industries where workers are potentially exposed to hazards.
    Acquiring data from these sources is straightforward and usually 
achieved through standard procedures. However, these sources often 
contain data gaps or inconclusive information. Thus, new sources of 
information are needed to fill existing data gaps and strengthen OSHA's 
analyses.
    Since similar types of data are currently being developed and 
submitted by manufacturers and importers under REACH, this information 
could provide an additional reference source for OSHA to utilize. The 
incorporation of REACH data into OSHA's technological feasibility 
analyses could greatly assist the Agency in creating a more exhaustive, 
thorough, and complete analysis. The information developed during the 
REACH registration process could help OSHA better understand the 
industries, uses, processes, and products in which a chemical of 
concern is used, gain knowledge about the risk management measures and 
controls currently in place, and develop scenarios where exposure may 
be greatest. Exposure information generated by manufacturers in a 
chemical safety assessment could be valuable for completing exposure 
profiles on chemicals where current references for field sampling 
analytical data are limited. In addition, utilizing information 
presented in exposure scenarios that describe the conditions under 
which a chemical can be used safely (i.e., risk management measures and 
operating conditions) could provide insight on currently employed 
industry control methods and their effectiveness.
    While the benefits of incorporating REACH data into OSHA's 
technological feasibility analyses seems promising, challenges such as 
data access and data validity have been identified as potential 
drawbacks. Despite provisions under REACH that require the public 
availability of data and the sharing of data with other government 
agencies, the European Chemicals Agency, which maintains the REACH 
databases, has not

[[Page 61401]]

yet made some of the information available, including information 
generated for and compiled in the chemical safety assessment. 
Additionally, some manufacturers and importers may be prohibited from 
sharing the data generated for REACH directly with other entities for 
non-REACH purposes due to agreements made among the members of groups 
organized under REACH to more efficiently share the information needed 
for the registration of a chemical.
    Question IV.B.7: How can exposure information in REACH be 
incorporated into OSHA's technological feasibility analysis?
c. Technological Feasibility Analysis With a Focus on Industries With 
Highest Exposures
    OSHA's technological feasibility analysis is one of the most 
resource-intensive parts of the rulemaking process. OSHA typically 
analyzes exposures in all industries and job categories within those 
industries that show potential for exposures and determine whether a 
proposed exposure limit can be achieved in most operations most of the 
time. These can range from industries that are constantly experiencing 
exposures in most job categories above an existing PEL or the 
regulatory alternatives, to industries where only a few job categories 
have shown elevated exposures. OSHA has also utilized an application 
approach in which it analyzed exposure associated with a specific 
process across a number of different industries.
    The Agency is investigating whether it is appropriate to focus 
future technological feasibility analyses only on job categories that 
have the highest exposures. An analysis performed in this manner may 
reduce the amount of time and money OSHA has to expend to prove 
feasibility. In many cases the control methods applicable for one 
industry may also be effective in reducing exposures in other 
industries. By determining the additional engineering controls and work 
practices necessary to reduce the most elevated exposures to a level 
specified by a regulatory alternative, the Agency could propose that 
similar control strategies (wherever applicable) would also be 
effective in reducing lesser exposures to that same level. In other 
words, by making feasibility findings in the most problematic 
industries, OSHA would argue that all other industries would also be 
able to comply with a regulatory alternative. A related possibility is 
for OSHA to make a feasibility determination based on enforcement 
activities of the proposed or lower PEL in other geographic 
jurisdictions, e.g., other states.
    Question IV.B.8: To what extent and in what circumstances should 
OSHA argue that feasibility for a regulatory alternative can be 
established by proving the feasibility of reducing the highest 
exposures to the level proposed by that regulatory alternative?
    Question IV.B.9: To what extent and in what circumstances can OSHA 
argue that feasibility for a regulatory alternative can be established 
by the enforcement of a lower PEL [e.g., the 1989 PEL (See Appendix B)] 
by an individual state or states?
    Question IV.B.10: What are the appropriate criteria that OSHA 
should use to assess whether control strategies implemented in a 
process from one industry are applicable to a process from another 
industry (e.g., similarity of chemicals, type, extent and duration of 
exposures, similar uses)?
    Question IV.B.11: Regardless of the industries involved, are there 
criteria that OSHA should use to show that control strategies 
implemented in a process from one operation are applicable to a process 
from another operation? Please explain.
    The Agency realizes that analyses performed in this manner may have 
some implications for smaller firms that may find it harder to 
implement resource intensive control strategies than larger firms. 
Additionally, the control strategies from the most problematic 
industries may not be similar to those that may be needed for 
industries with lower exposures because the processes and sources of 
exposure require different control methods.
    Question IV.B.12: How should OSHA take into consideration the size 
of a business of facility when determining technological feasibility?

C. Economic Feasibility in Health Standards

    The purpose of this section is (1) to discuss how and why OSHA 
currently conducts its economic feasibility analysis of health 
standards, and (2) to examine approaches to economic feasibility that 
might involve less time and fewer resources.
1. OSHA's Current Approach to Economic Feasibility
    The Agency's existing approach to economic feasibility rests 
directly on relevant language in the OSH Act, as interpreted by the 
courts, requiring OSHA to establish that new standards are economically 
feasible. OSHA also conducts economic analysis of its regulations in 
compliance with other legislation and as a result of executive orders 
that require analysis of the benefits and costs of a regulation as a 
whole, and in the case of the Regulatory Flexibility Act, some estimate 
of the economic impacts on small entities. However, the degree of 
industry detail provided in OSHA's economic analyses is primarily a 
function of judicial interpretation of the economic feasibility 
requirements of the OSH Act. The development of the law on economic 
feasibility is discussed in detail in Section III. Below we discuss 
potential alternatives to current methods of economic feasibility 
analysis, and then follow with a brief discussion on how the other 
analytical requirements OSHA is required to meet might be satisfied.
    As guided by the courts, OSHA develops economic feasibility 
analyses that cover every affected industry and process. OSHA has not 
always taken this position. For example, in its economic and 
technological feasibility analysis of benzene, OSHA examined only 
industries believed to be the worst in terms of significant exposure to 
benzene. Since then, however, OSHA has attempted to cover all affected 
industries in its feasibility analysis.
    The courts have suggested that the economic feasibility analysis 
must be reasonably detailed. In the Air Contaminants case, the court 
said:

    Indeed, it would seem particularly important not to aggregate 
disparate industries when making a showing of economic feasibility . 
. . [R]eliance on such tools as average estimates of cost can be 
extremely misleading in assessing the impact of particular standards 
on individual industries. AFL-CIO v. OSHA, 965 F.2d 962, 982 (11th 
Cir. 1992) (``Air Contaminants''). (Ex. #8)

However, the court added:

    We are not foreclosing the possibility that OSHA could properly 
find and explain that certain impacts and standards do apply to 
entire sectors of an industry. Two-digit SICs could be appropriate, 
but only if coupled with a showing that there are no 
disproportionately affected industries within the group. Air 
Contaminants, 965 F.2d at 982 n.28

    In the hexavalent chromium case, Public Citizen Health Research 
Group v. United States Dep't of Labor, 557 F.3d 165, 178 (3d Cir. 2009; 
Ex. #14), the court recognized that OSHA had the flexibility to 
demonstrate technological feasibility on a process or activity rather 
than industry-by-industry basis, if the processes or activities are 
sufficiently similar from industry to industry. The court, however, did 
not address the question of whether the same flexibility applies to 
economic feasibility. OSHA, especially in health standards, has tried

[[Page 61402]]

to provide the most detailed analysis of industries and processes that 
resources permit. For most recent health standards, this has meant the 
use of the lowest level industry codes for which industry data are 
available, and where more than one process is used in an industry, 
consideration of each process separately. Further, in order to assure 
that a regulation does not alter the competitive structure of an 
industry, OSHA normally analyses three size classes of employer within 
each industry: All establishments, small firms as defined by SBA, and 
small firms with fewer than twenty employees (always smaller than the 
SBA definitions). For the typical OSHA substance-specific health 
standard, OSHA analyses each of the controls for each of the many 
processes in which the substance might appear, and then of each 
industry in which any process might appear, and then of three sizes of 
establishment within the industry. Finally, OSHA examines the varying 
levels of exposure and controls within an industry and develops 
analyses that reflect these differences within an industry. In terms of 
the form of the analysis, OSHA has followed the advice of the D.C. 
Circuit to ``construct a reasonable estimate of compliance costs and 
demonstrate a reasonable likelihood that these costs will not threaten 
the existence or competitive structure of an industry.'' United 
Steelworkers v. Marshall, 647 F.2d 1189, 1272 (D.C. Cir. 1980; Ex. #12) 
(``Lead I'').
    In response to this guidance, OSHA develops detailed estimates of 
the costs of a health standard for each affected industry, and by the 
three size categories of establishment. The result is that the economic 
analyses of health standards routinely contain a series of tables 
showing costs for each industry by multiple size classes of firms 
within the industry, and sometimes for more than one process per 
industry. Each entry in these tables is documented by detailed 
explanations of how the costs were estimated for each industry and size 
class and level of exposure.
    OSHA then makes a determination for each industry whether or not 
these costs are likely to threaten the existence or competitive 
structure of that industry. In order to do this, OSHA first constructs 
a ``screening analysis'' for each industry. For the purposes of this 
screening analysis, OSHA combines its estimates on the costs per 
establishment of various sizes with statistical data on the profits and 
revenues of the affected establishment sizes, and then calculates costs 
as a percentage of profits and revenues. For most industries, the costs 
in comparison to revenues and profits are so small that, in OSHA's 
view, no reasonable person could think that the costs could possibly be 
expected to threaten the existence or competitive structure of an 
industry. Where the costs are not this small, OSHA conducts a variety 
of further economic analysis, depending on the economic situation, 
nature of the costs, the affected industry, and the economic data 
available.
    This basic approach to economic feasibility analysis has been used 
for many health standards, and the approach has generally been 
successful in assuring that OSHA standards are economically feasible. 
In the PELs rulemaking, where OSHA tried a more general approach, the 
court found the level of detail inadequate. Similarly, OSHA has 
encountered problems when the Agency did not have an adequate level of 
detail with respect to the exposure profile and the technological 
feasibility analysis, such as for dry-color formulators of cadmium 
pigments. OSHA's eight lookback studies, conducted under both Sections 
610 of the Regulatory Flexibility Act and Section 5 of Executive Order 
12866, have not found any instance in which subsequent study showed 
that a standard had threatened the existence of or brought about 
massive dislocation within an industry.
    OSHA can reasonably say that it has found a methodology such that 
the Agency's determinations of economic feasibility have both been 
considered adequate by the courts and proven to be accurate in 
determining regulations to be feasible when re-evaluated by 
retrospective analysis. However, the resulting methodology is extremely 
resource intensive and time-consuming because OSHA always has to make 
detailed cost estimates and provide detailed statistical data for every 
single process and industry affected. For this reason, OSHA wants to 
consider whether there may be methods that can short-cut this process 
and still meet all of OSHA's legal requirements.
    The remainder of this section examines two kinds of alternative 
approaches to accelerating the process and reducing the resources 
needed to produce health standards. One kind of alternative involves 
formulating health standards differently. The second kind involves 
different kinds of analysis OSHA might perform.
2. Alternative Approaches to Formulating Health Standards That Might 
Accelerate the Economic Feasibility Analysis
    One approach to simplifying, speeding up, and making the 
development of standards less resource intensive would be to have the 
standards themselves address health issues in a way that involves less 
analysis for any given standard. Health standards can be analyzed 
faster to the extent that there are fewer processes and/or fewer 
industries to analyze. It would be less time consuming for OSHA to 
analyze a health standard for a single process rather than a single 
substance that is found in dozens of processes. OSHA already has a 
variety of process-oriented standards that partially address health 
hazards in such areas as abrasive blasting, welding, and 
electroplating. Control banding also represents an approach that, 
following the hazard assessment, examines controls for specific 
processes. In control banding, the hazards are generic, but the 
controls are process specific. Process-oriented approaches would be 
most useful for processes widely used in a variety of settings--
abrasive blasting, degreasing, welding, etc. Industry-by-industry 
economic feasibility analysis for a process-oriented approach would be 
enormously simplified by the fact the controls and their costs would be 
very similar across industries. As a result, OSHA could develop more 
detailed and more secure cost estimates, with full opportunities for a 
variety of affected parties to comment on those estimates. This 
approach might also serve to greatly simplify the technological 
feasibility analysis. On the other hand, since process-oriented 
standards commonly involve multiple substances, risk assessment issues 
might be more complex.
    A related approach to speeding up at least portions of substance 
specific health standards might be to regulate a single substance 
process by process in multiple rulemakings--for example, regulate 
exposures to hexavalent chromium in electroplating, then in welding, 
and then painting. By producing process standards in this manner, 
rather than waiting until analyses of all processes and industries is 
completed, OSHA could potentially address the most severe exposures 
much more rapidly. This approach could also allow OSHA to ignore 
processes where the exposures are likely to be small and the chance of 
exceeding a PEL minimal. Though this approach might result in portions 
of a substance-specific standard being produced more quickly, the 
approach would probably require more resources for multiple hearings 
and docket analyses. A major disadvantage of this approach is that it 
would result in the possibility that workers in industries not yet 
regulated

[[Page 61403]]

would have to endure exposures higher than those in regulated 
industries. Another disadvantage might be that the risk assessment 
would be subject to multiple public hearings as each industry or 
process was regulated.
3. Alternative Analytic Approaches to Economic Feasibility of Health 
Standards
    A different approach to producing less resource-intensive and time-
consuming economic feasibility analyses would be to re-examine whether 
OSHA's basic approach of estimating the costs of each process, 
industry, size class, and possible level of control is really necessary 
in all cases given how the courts have defined economic feasibility. 
The key to meeting the legal requirements is to return to the concept 
of economic feasibility. In the Lead I decision, the court stated:

    A standard is feasible if it does not threaten ``massive 
dislocation'' to . . . or imperil the existence of the industry. No 
matter how initially frightening the projected . . . costs of 
compliance appear, a court must examine those costs in relation to 
the financial health and profitability of the industry and the 
likely effect of such costs on unit consumer prices. More 
specifically . . . the practical question is whether the standard 
threatens the competitive stability of an industry. Lead I, 647 F.2d 
at 1265 (citations omitted). (Ex. #12)

    As the court recognized, this is a strong criterion. In the real 
world, industries are rarely eliminated or have their competitive 
structure radically altered for reasons related to changes in their 
costs, and it is changes in costs that courts recognized as the 
principle reason a regulation might not be economically feasible. 
Radical changes in industries tend to come from two major causes. Most 
are the result of changes in demand such that the public is no longer 
interested in the product or service an industry provides, for such 
reasons as technological obsolescence or the existence of better 
substitutes. Some radical changes in industries are the result of 
foreign competition. However, foreign competition applies largely, in 
an OSHA context, to manufacturing, but not to construction, utilities, 
domestic transportation, or most services that OSHA regulates.
    OSHA is not aware of any instance in which an OSHA regulation 
eliminated or altered the competitive structure of an industry--though 
in some cases, a combination of liability-based concerns, environmental 
regulations, and OSHA regulation may have radically altered the use of 
a product. For example, asbestos is not used in many applications where 
it was once commonplace. Benzidine-based dyes have disappeared from the 
U.S. marketplace. However, these cases had no effect on the viability 
of user industries or their employment. Insulation contractors still 
install insulation--it just no longer contains asbestos. Dyers continue 
to dye textiles and leather all the colors benzidene-based dyes 
imparted, but without using benzidene-based dyes. The chief effect has 
been substitution away from a substance. This has resulted in serious 
economic impacts on a limited number of producers of the substance but 
little economic impact on the thousands of users of the substance who 
simply found a substitute. It would seem that such substitution away 
from a substance is not the kind of economic change that would make a 
regulation economically infeasible.
    OSHA might be able to place major emphasis on evidence that a 
significant portion of an industry is already meeting a standard. Such 
evidence is an obvious indication that a standard is both 
technologically and economically feasible for that industry. After all, 
the actual fact that a majority of employers of all sizes in an 
industry is meeting a standard, while remaining viable, should be more 
convincing than a set of cost estimates in an economic analysis 
predicting that employers in a given industry could meet the standard. 
Actual empirical evidence of a proposition is normally considered 
superior to theoretical evidence for a proposition. There are several 
reasons why many or most employers in an industry may already meet a 
standard--these include ease of meeting the standard, industry 
consensus standards, and concern about liability.
    Similarly, the fact that a state or other jurisdiction has already 
implemented a requirement and that firms within the state are generally 
following the requirement would represent very strong evidence that a 
requirement is economically and technologically feasible. For example, 
twenty-two states currently operate their own OSHA programs that cover 
both private sector and State and local government employees, and five 
states cover public employees only. Of the twenty-two states that cover 
both private and public sector employees, five states (South Carolina, 
Minnesota, Tennessee, Vermont and Washington) are still enforcing the 
1989 PELs, and did not revert to the less protective PELs when the 
Court remanded the Air Contaminants rule. (Ex. #8) Michigan is also 
enforcing the 1989 PELs in general industry, but not in construction. 
Three states (Connecticut, Illinois, and New York) are enforcing the 
1989 PELs in the public sector only. California enforces its own PELs 
which in many cases are substantially lower than OSHA's. Situations in 
which most firms in a state meet a potential requirement of a standard 
are particularly convincing because they show that employers are not 
only able to carry out the requirement, but can do so even in 
competition with employers who are not required to meet such a 
requirement.
    Nevertheless, OSHA is aware that some care must be taken with 
evidence that all or most firms in an industry or in an industry within 
a state meet a requirement. It is particularly important to determine 
whether those who do not meet the requirement might require 
fundamentally different controls, have different costs, or operate in a 
different market in spite of being in the same statistical industry. 
Consider a standard addressing a specific metal. Most firms in an 
industry may find the standard easy to meet because they only use the 
metal in alloys that call for a very small percentage of the metal. 
However, those firms that use alloys with high percentages of the metal 
might be unable to meet the standard. This would not be apparent 
looking solely at aggregate industry data. OSHA should take reasonable 
steps to determine that those that did not meet the standard do not 
have important technological or economic characteristics that are 
different from those that did.
    Under this approach, OSHA could conclude that a standard is 
feasible where a state already had such a standard if it first 
determines that (1) the standard is enforced; (2) employers in the 
state in fact meet the standard; and (3) which of the relevant 
industries and technologies are represented within that state.
    However, in spite of these caveats, it would frequently take OSHA 
less time and fewer resources to demonstrate that a standard is 
technologically and economically feasible by showing that employers in 
the industry already meet the standard than by the full identification 
of control technologies, exposure levels achieved by those 
technologies, the costs of the technologies, and the economic impacts 
of these technologies that OSHA now undertakes.
    As noted above, at one point in the Lead I decision, the court 
suggested OSHA develop a ``reasonable estimate of costs.'' However at 
another point in this decision the same court clarified:

    [T]he court probably cannot expect hard and precise estimates of 
costs. Nevertheless,

[[Page 61404]]

the agency must of course provide a reasonable assessment of the 
likely range of costs of its standard, and the likely effects of 
those costs on the industry . . . And OSHA can revise any gloomy 
forecast that estimated costs will imperil an industry by allowing 
for the industry's demonstrated ability to pass through costs to 
consumers. Lead I, 647 F.2d at 1266. (Ex. #12)

    OSHA has made little use of the concept of a likely range of costs 
or of developing generic approaches to determining a reasonable 
likelihood that these costs will not threaten the existence or 
competitive structure of an industry.
    OSHA could significantly reduce its resource and time expenditures 
by providing ranges of costs, given that the upper end of the range 
provides ``a reasonable likelihood that these costs will not threaten 
the existence or competitive structure of an industry.'' Such an 
approach would not only reduce OSHA's time and effort but also that of 
the interested public. Too often stakeholders devote significant time 
and effort questioning cost estimates when even the stakeholders' 
alternative cost estimate would have no effect on whether the costs 
would threaten the existence or competitive structure of an industry. 
The simple fact is that both OSHA and its stakeholders spend far too 
much time examining the accuracy of cost estimates even when the 
highest cost estimates considered would have little effect on the 
determination of economic feasibility.
    OSHA could also make more effort to clarify historically the 
circumstances under which regulations of any kind have eliminated or 
altered the competitive structure of an industry. As noted above, OSHA 
has yet to find an instance in which OSHA regulations eliminated or 
altered the competitive structure of an industry. A more thorough 
exploration of past experiences with OSHA regulations might simplify 
OSHA analyses and make it more empirically based in a variety of 
situations.
    OSHA believes that it may be able to meet the requirements of 
Executive Orders 12866 and 13563 and the Regulatory Flexibility Act 
without the kind of industry-by-industry detail that OSHA now provides 
in its economic analyses. The requirements of executive orders for 
analysis of costs and benefits do not include requirements that they be 
made available on an industry-by-industry basis, and OIRA encourages 
the reporting of ranges as opposed to precise but possibly inaccurate 
point estimates. OSHA believes that the requirements of the executive 
orders and for determining if a regulatory flexibility analysis or 
Small Business Regulatory Enforcement Fairness Act (SBREFA) Panel is 
needed can, in most cases, be met by focusing on those sectors and size 
classes where the most severe impacts are expected.
    Question IV.C.1: Should OSHA consider greater use of process 
oriented regulations, such as regulations on abrasive blasting, 
welding, or degreasing, as an approach to health standards? Should such 
an approach be combined with a control banding approach?
    Question IV.C.2: Should OSHA consider issuing substance-specific 
standards in segments as the analysis of a particular process or 
industry is completed rather than waiting until every process and 
industry using a substance has been thoroughly analyzed?
    Question IV.C.3: To what extend and in what circumstances can OSHA 
argue that feasibility for a regulatory alternative can be established 
by the enforcement of a lower PEL (e. g., the 1989 PEL) by an 
individual state or states?
4. Approaches to Economic Feasibility Analysis for a Comprehensive PELs 
Update
    Following the Eleventh Circuit's direction in the Air Contaminants 
case (956 F.2d at 980-82; Ex. #8) and in Color Pigments Mfrs. Ass'n v. 
OSHA, 16 F.3d 1157, 1161-64 (11th Cir. 1994; Ex. #13), OSHA has 
typically performed its economic feasibility analyses on an industry-
by-industry basis using the lowest level industry codes for which 
industry data are available. While such an approach best insures that 
the effect of the standard on small industry segments will be 
considered, it is very resource intensive. If OSHA were required to use 
of this approach to address feasibility for a comprehensive PELs 
update, which would require addressing the feasibility of new PELs for 
hundreds of chemicals in hundreds of industry segments, it might 
require more resources than the agency would have available.
    There are good reasons to think that the OSH Act does not require 
such a detailed level of economic analysis to support a feasibility 
finding. The purpose of the OSH Act is to assure all workers ``safe and 
healthful working conditions,'' and therefore it is unlikely that 
Congress intended for OSHA to meet such demanding analytical 
requirements if it meant that the agency could not issue a standard 
addressing well-recognized hazards. See, e.g., Public Citizen Health 
Research Group v. Dep't of Labor, 557 F.3d 165, 178-79 (3d Cir. 2009; 
Ex. #14) (``Hexchrome'') (rejecting interpretation that OSH Act 
required OSHA to research all workplace operations involving hexavalent 
chromium exposure to prove feasibility, which would ``severely hinder 
OSHA's ability to regulate exposure to common toxins''); American 
Dental Ass'n v. Martin, 984 F.2d 823, 827 (7th Cir. 1993; Ex. #53) 
(OSHA not required to regulate ``workplace by workplace''); Assoc. 
Bldrs & Contrs. Inc. v. Brock, 862 F.2d 63, 68 (3d Cir. 1988; Ex. #54) 
(``A requirement that the Secretary assess risk to workers and need for 
disclosure with respect to each substance in each industry would 
effectively cripple OSHA's performance of the duty imposed on it by 29 
U.S.C. 655(b)(5); a duty to protect all employees, to the maximum 
extent feasible.'').
    Indeed, the requirement that an OSHA standard not threaten 
``massive dislocation'' or ``imperil the existence'' of an industry is 
an outgrowth of the idea that OSHA may adopt standards that may cause 
marginal firms to go out of business if they are only able to make a 
profit by endangering their employees. See Industrial Union Dep't, AFL-
CIO v. Hodgson, 499 F.2d 467, 478 (XX Cir. 1974; Ex. #55). And the 
notion that the determination must be made on an industry basis arises 
from cases in which OSHA attempted to do just that; the statute does 
not require feasibility to be evaluated in this way. See Lead I, 647 
F.2d at 1301 (where OSHA attempted to determine the feasibility of the 
lead standard on an industry-by-industry basis, noting that the parties 
did not dispute that feasibility was to be determined in that manner); 
Hexchrome, 557 F.3d at 178 (``nothing in 29 U.S.C. 655(b)(5) requires 
OSHA to analyze employee groups by industry, nor does the term 
`industry' even appear''). The approach articulated by the Air 
Contaminants court, which places an affirmative duty on OSHA to 
establish that proposed standards would not threaten even the smallest 
industry segments before adopting a standard, creates a heavy 
analytical burden that is not necessarily required by the statute.
    As the Lead I court notes, in the case of a standard requiring an 
employer to adopt only those engineering and administrative controls 
that are feasible, what really is at stake in OSHA's feasibility 
determinations is whether OSHA has justified creating a presumption 
that the implementation of such controls are feasible. 647 F.2d at 
1269-70. Thus, OSHA need not ``prove the standard certainly feasible 
for all firms at all times in all jobs.'' 647 F.2d at 1270. The court 
recognized that under

[[Page 61405]]

this approach, some employers might not be able to comply with a 
standard, but noted that the statute offers those employers several 
alternatives: requesting a variance, asserting a feasibility defense in 
an enforcement proceeding, or petitioning the agency to revise the 
standard. 647 F.2d at 1270.
    As noted above, most of OSHA's current PELs are over 40 years old, 
and are based on science that is even older. It seems unlikely that a 
statute enacted to protect workers against chemical health hazards 
would preclude OSHA from updating hundreds of those PELs unless it can 
show that each is feasible in each of the smallest industry segments in 
which the chemical is used. The question, then, is what level of 
analysis would be sufficient to justify a presumption that the standard 
is feasible, shifting the burden to the employer as allowed by Lead I.
    If OSHA moved forward with a global PELs update, the Agency might 
consider analyzing economic feasibility at a higher level than it has 
typically employed in substance specific health standards. In order to 
do so, OSHA would need to develop criteria as to what chemicals are 
suited to be part of a PELs rulemaking rather than subject to a 
substance-specific rulemaking. For example, if the rulemaking record 
showed that, for a specific chemical application group, generally 
available exposure controls had not been successful in achieving the 
proposed PEL, then this chemical or at least the application group 
would be transferred from updated PELs rulemaking to being a candidate 
for further study and possible inclusion in a substance-specific 
rulemaking. The goal under this approach would be to develop a 
reasonable basis for believing that the chemicals and application 
groups remaining in a PELs-update rulemaking are (1) likely to be 
economically feasible; and (2) subject to relatively simple and easily-
costed controls that are likely to be relatively homogenous across 
industries.
    As a result, rather than accumulating data at the lowest industry 
level available regarding exposures and controls needed for each 
chemical for which a new PEL would be adopted, OSHA could consider a 
more general approach. For example, OSHA might conduct an economic 
feasibility analysis at the industry level for which sufficient 
exposure data are currently available. It might use a control banding 
approach in order to determine the types of controls necessary to 
comply with a new PEL, and validate models to implement each type of 
control based on variables such as establishment size and process type. 
The results of this analysis would be used to build up costs at the 
industry level. It is possible that the results of such an analysis 
might be better characterized in ranges, and of sufficient precision to 
establish feasibility at a level as low as the method that OSHA 
typically uses. Under this approach, a determination made in this way 
would be presumptively sufficient to establish feasibility in the 
absence of contrary evidence provided by commenters. If such evidence 
were presented, OSHA would address it and incorporate it into its 
feasibility analysis supporting the final rule.
    Question IV.C.4: Should OSHA consider providing ranges of costs for 
industries in situations where even the upper range of the costs would 
obviously not provide a threat to the existence of competitive 
structure of an industry?
    Question IV.C.5: What peer-reviewed economics literature should 
OSHA consult when determining whether the competitive structure of an 
industry would be altered? Are there any instances where an OSHA 
standard did threaten the existence or competitive structure of an 
industry? What were they and what is the evidence that an OSHA standard 
was the origin of the difficulties?
    Question IV.C.6: Should OSHA consider and encourage substitution 
and elimination of substances that cause significant risk in workplaces 
even if such substitution or elimination will eliminate or alter the 
competitive structure of the industry or industries that produce the 
hazardous substance?
    Question IV.C.7: Are there other approaches OSHA could use that 
would provide for more timely and less resource-intensive economic 
feasibility analyses?
    Question IV.C.8: In determining the level of industry detail at 
which OSHA should conduct an economic feasibility analysis for a 
comprehensive PELs update, what considerations should OSHA take into 
account? What level of detail do you think is sufficient to justify the 
presumption of feasibility for such a standard? Please explain.
    Question IV.C.9: Are the methodologies suggested above appropriate 
to establish economic feasibility for a comprehensive PELs update? Why 
or why not? What other cost effective methods are available for OSHA to 
establish economic feasibility for such a rulemaking?
    Question IV.C.10: What factors should OSHA consider in determining 
whether a chemical should be part of an overall PELs update or subject 
to substance-specific rulemaking? Should OSHA consider some application 
groups for a given chemical as subject to a PELs update rulemaking if 
some other application groups present feasibility issues that make them 
inadvisable candidates for a PELs rulemaking?

V. Recent Developments and Potential Alternative Approaches

    Wide access to information on the Internet and the development of a 
global economy has shifted occupational safety and health from a 
domestic to a global concern. Countries often struggle with similar 
experiences and challenges related to exposure to hazardous chemicals, 
and sharing information and experiences across borders is a common 
practice. Global data sharing allows for the widespread and rapid 
dissemination of available chemical information to employers, 
employees, managers, chemical suppliers and importers, risk managers, 
or anyone with access to the Internet. The development of hazard 
assessment tools that take advantage of readily available hazard 
information make it possible for employers to implement effective 
exposure control strategies without the need to rely solely on OELs.
    Some of these resources for data and tools that OSHA may use more 
systematically in the future for hazardous chemical identification and/
or assessment are addressed in Section V.

A. Sources of Information About Hazardous Chemicals

    In order to design and implement appropriate protective measures to 
control chemical exposures in the workplace, employers need reliable 
information about the identities and hazards associated with those 
chemicals. OSHA is considering ways in which recently developed data 
sources could be used by the Agency and employers to more effectively 
manage chemical hazards in the workplace. Developments in the use of 
structure--activity data for grouping chemicals having similar 
properties, the Environmental Protection Agency's High Production 
Volume (HPV) Chemicals, OSHA's Hazard Communication standard and the 
Globally Harmonized Hazard Communication Standard, health hazard 
banding, the European Union's Registration, Evaluation, Authorization, 
and Restriction of Chemicals (REACH), are discussed here. OSHA is 
interested in stakeholders' comments on how the Agency may make use of 
any of these data sources or other alternative data or information 
sources not discussed here

[[Page 61406]]

to better manage workplace chemical exposures.
1. EPA's High Production Volume Chemicals
    One potential source of relevant and timely information on 
chemicals that OSHA may make better use of in the future is the data on 
High Production Volume chemicals that are being collected by the EPA 
and the Organization for Economic Cooperation and Development (OECD). 
The OECD program lists approximately 5,000 chemicals on its list, and 
OSHA has determined that 290, or 62 percent of the 470 substances with 
PELs are included on the OECD list.
    Under the HPV program, EPA has identified over 2,000 chemicals that 
are produced in quantities of one million pounds a year or more in the 
United States. It would appear that these chemicals are thus 
economically significant in the US, and there are likely to be a large 
number of workers exposed to them. Through the HPV Challenge program, 
EPA encouraged industry to make health and environmental effects data 
on these HPV chemicals publicly available. To date, data on the 
properties of approximately 900 HPV chemicals has been made available 
through the Agency's High Production Volume Information System (HPVIS) 
(U.S. EPA, 2012a; Ex. #56). For each HPV chemical, the database 
includes information on up to 50 endpoints on physical/chemical 
properties, environmental fate and pathways, ecotoxicity, and mammalian 
health effects. EPA has also used this information to generate publicly 
available chemical hazard characterizations, which provide a concise 
assessment of the raw technical data on HPV chemicals and evaluate the 
quality and completeness of the data received from industry (U.S. EPA, 
2013d; Ex. #63).
    Data on HPV chemicals submitted through the OECD's program are 
available through its Global Portal to Information on Chemical 
Substances, eChemPortal (OECD, 2013; Ex. #58). In addition to searching 
data collected through the EPA HPV and OECD HPV programs, eChemPortal 
allows for simultaneous searching of 26 databases for existing publicly 
available data on the properties of chemicals, including: physical/
chemical properties, environmental fate and behavior, ecotoxicity, and 
toxicity.
    Question V.A.1. How might publicly available information on the 
properties and toxicity of HPV chemicals be utilized by employers to 
identify chemical hazards and protect workers from these hazards? OSHA 
is also interested to hear from commenters who may currently make use 
of these data in their worker protection programs.
2. EPA's CompTox and ToxCast
    EPA has also launched an effort to prioritize the tens of thousands 
chemicals that are currently in use for testing and exposure control. 
Through its computational toxicology (CompTox) research, the U.S. 
Environmental Protection Agency (EPA) is working to figure out how to 
change the current approach used to evaluate the safety of chemicals. 
CompTox research integrates advances in biology, biotechnology, 
chemistry, and computer science to identify important biological 
processes that may be disrupted by the chemicals and trace those 
biological disruptions to a related dose and human exposure. The 
combined information helps prioritize chemicals based on potential 
human health risks. Using CompTox, thousands of chemicals can be 
evaluated for potential risk at a small cost in a very short amount of 
time. A major part of EPA's CompTox research is the Toxicity Forecaster 
(ToxCastTM). ToxCast is a multiyear effort launched in 2007 
that uses automated chemical screening technologies, called 
``highthroughput screening assays,'' to expose living cells or isolated 
proteins to chemicals. The cells or proteins then are screened for 
changes in biological activity that may suggest potential toxic 
effects.
    These innovative methods have the potential to limit the number of 
required animal-based laboratory toxicity tests while, quickly and 
efficiently screening large numbers of chemicals. The first phase of 
ToxCast, called ``proof of concept'', was completed in 2009, and it 
evaluated more than 300 well studied chemicals (primarily pesticides) 
in more than 500 high-throughput screening assays. Because most of 
these chemicals already have undergone extensive animal-based toxicity 
testing, this enables EPA researchers to compare the results of the 
high-throughput assays with those of the traditional animal tests. 
(EPA, 2014a; Ex. #59)
    Completed in 2013, the second phase of ToxCast evaluated over 2,000 
chemicals from a broad range of sources, including industrial and 
consumer products, food additives, and potentially ``green'' chemicals 
that could be safer alternatives to existing chemicals. These chemicals 
were evaluated in more than 700 high-throughput assays covering a range 
of high-level cell responses and approximately 300 signaling pathways. 
ToxCast research is ongoing to determine which assays, under what 
conditions, may lead to toxicological responses. The results of this 
research then can be used to suggest the context in which decision 
makers can use the data. The EPA's Endocrine Disruptor Screening 
Program already has begun the scientific review process necessary to 
begin using ToxCast data to prioritize the thousands of chemicals that 
need to be tested for potential endocrine-related activity. Other 
potential uses include prioritizing chemicals that need testing under 
the Toxic Substances Control Act and informing the Safe Drinking Water 
Act's contaminant candidate lists. (EPA, 2014b; Ex. #60) EPA 
contributes the results of ToxCast to a Federal agency collaboration 
called Toxicity Testing in the 21st Century (Tox21). Tox21 pools those 
results with chemical research, data and screening tools from the 
National Toxicology Program at the National Institute of Environmental 
Health Science, the National Institutes of Health's National Center for 
Advancing Translational Sciences and the Food and Drug Administration. 
(EPA, 2014b; Ex. #60)
    Thus far, Tox21 has compiled highthroughput screening data on 
nearly 10,000 chemicals. All ToxCast chemical data are publicly 
available for anyone to access and use through user-friendly Web 
applications called interactive Chemical Safety for Sustainability 
(iCSS) Dashboards at http://actor.epa.gov/actor/faces/.
    OSHA could use this publicly available information on chemical 
properties and toxicity as a part of the Agency's risk assessments that 
support the revision and development of permissible exposure limits. 
Tox21 could also be used by the Agency for screening chemicals and 
prioritizing for risk management.
    Question V.A.2. How might the information on the properties and 
toxicity of chemicals generated by CompTox, ToxCast, and/or Tox21 be 
utilized by employers to identify chemical hazards and protect workers 
from these hazards? OSHA is also interested to hear from commenters who 
may currently make use of these data in their worker protection 
programs.
3. Production and Use Data Under EPA's Chemical Data Reporting Rule
    Under the EPA's Chemical Data Reporting (CDR) Rule, issued in 2011, 
EPA collects screening-level, exposure-related information on certain 
chemicals included on the Toxic Substances Control Act (TSCA) Chemical 
Substance Inventory and makes that information publicly available to 
the extent possible. The CDR rule amended the TSCA Inventory Update 
Reporting (IUR) rule

[[Page 61407]]

and significantly increased the type and amount of information covered 
entities are required to report. The 2012 submissions included data on 
more chemicals and with more in-depth information on manufacturing 
(including import), industrial processing and use, and consumer and 
commercial use than data collected under the IUR in 2006 (U.S. EPA, 
2013a; Ex. #1).
    The expanded reporting on chemical production and use information 
under the CDR could help OSHA better understand how workers are exposed 
to chemicals and the industries and occupations where exposures to 
chemicals might occur.
4.Structure-Activity Data for Chemical Grouping
    Although toxicity testing for chemicals has increased greatly since 
the passage of the Toxic Substances Control Act (15 U.S.C. 2601-2629; 
Ex. #62) in the United States, and with similar legislation elsewhere, 
toxicity data is only publicly available for a fraction of industrial 
chemicals. Since the enactment of TSCA and creation of the TSCA 
Interagency Testing Committee (U.S. EPA, 2013c; Ex. #57), the ITC has 
recommended testing for hundreds of chemicals, and chemical producers 
have conducted more than 900 tests for these chemicals. However, 
potentially thousands of industrial chemicals have not been tested.
    With the rapidly expanding development of new chemical substances 
and mixtures, the need for toxicity information to inform chemical 
safety management and public health decisions in a timely manner has 
exceeded the capacity of the government programs to provide those data. 
As a result, programs such as the Organization for Economic Cooperation 
and Development's (OECD) Screening Information Data Set (SIDS) and the 
U.S. EPA High Production Volume (HPV) Challenge programs were designed 
to encourage the voluntary development of data. However, even with the 
creation of these non-statutory programs, potentially thousands of non-
HPV industrial chemicals go untested. Therefore, chemical 
prioritization for screening and testing requires the development and 
validation of standard methods to predict the human and environmental 
effects and potential fate of chemicals. Where screening and testing 
data are sparse, the use of predictive models called structural 
activity relations (SARs) or quantitative structural activity 
relationships (QSARs) can extend the use of limited toxicity and safety 
data for some untested chemicals (Russom et al., 2003; Ex. #64). QSARs 
are mathematical models that are used to predict measures of toxicity 
from physical characteristics of the structure of chemicals, known as 
molecular descriptors.
    Other U.S. and international agencies have explored the use of 
chemical groupings to regulate chemicals in order to fulfill their 
regulatory and statutory authorities. Under the TSCA Work Plan, the EPA 
announced in 2013 that it would begin to assess 20 flame retardant 
chemicals and three non-flame retardant chemicals. EPA utilized a 
structure-based approach, grouping eight other flame retardants with 
similar characteristics together with the chemicals targeted for full 
assessment in three groupings. EPA will use the information from these 
assessments to better understand the other chemicals in the group, 
which currently lack sufficient data for a full risk assessment.
    EPA uses chemical groupings to fill data gaps in its New Chemical 
Program. EPA's New Chemical Program, also under TSCA, requires anyone 
who plans to manufacture or import a new chemical substance into 
commerce to provide EPA with notice before initiating the activity. 
This is called a pre-manufacture notification (PMN). EPA received 
approximately 1,500 new chemical notices each year and has reviewed 
more than 45,000 from 1979 through 2005 (GAO, 2007; Ex. #65). Because 
TSCA does not require testing before submission of a PMN, SARs and 
QSARs are often used to predict the environmental fate and ecologic 
effects. In addition, the EPA makes predictions concerning chemical 
identity, physical/chemical properties, environmental transport and 
partitioning, environmental fate, environmental toxicity, engineering 
releases to the environment, and environmental concentrations. The 
agency uses a variety of methods to make these predictions that include 
SARs, nearest-analogue analysis, chemical class analogy, mechanisms of 
toxicity, and chemical industry survey data and the collective 
professional judgment of expert scientific staff, in the absence of 
empirical data. The agency uses these methods to fill data gaps in an 
assessment and to validate submitted data in notifications. Predictions 
are also made by the U.S. EPA Office of Pollution Prevention and Toxics 
(OPPT) under TSCA (Zeeman., 1995; Ex. #66). The OPPT has routinely used 
QSARs to predict ecologic hazards, fate, and risks of new industrial 
chemicals, as well as to identify new chemical testing needs, for more 
than two decades. OPPT SAR/QSARs for physical/chemical properties used 
for new chemical assessments are publically available (U.S. EPA, 2012b; 
Ex. #67).
    In Europe, internationally agreed-upon principles for the 
validation of (Q)SARs were adopted by OECD Member Countries and the 
Commission in 2004. In 2007, the Inter-organization Programme for the 
Sound Management of Chemicals, a cooperative agreement among United 
Nations Environmental Program (UNEP); International Labor Organization 
(ILO); Food and Agriculture Organization of the United Nations (FAO); 
World Health Organization (WHO); United Nations Industrial Development 
Organization (UNIDO), United Nations Institute for Training and 
Research (UNITAR) and Organization for Economic Co-operation and 
Development (OECD) published ``Guidance on Grouping of Chemicals'' as 
part of an ongoing monograph series on testing chemicals. REACH 
registrants may rely on (Q)SAR data instead of experimental data, 
provided the registrants can provide adequate and reliable 
documentation of the applied method and document the validity of the 
model. Validation focuses on the relevance and reliability of a model 
(ECHA, 2008; Ex. #68).
    The EU Scientific Committee on Toxicity, Ecotoxicity and the 
Environment (CSTEE) recommended, in their general data requirements for 
regulatory submission, that QSAR data may be used as well as animal 
data. A chemical category approach based on the metal ion has been 
extensively used for the classification and labeling of metal compounds 
in the EU. Other category entries are based on certain anions of 
concern such as oxalates and thiocyanates. For these EU classifications 
the category approach has often been applied to certain endpoints of 
particular concern for the compounds under consideration, but has not 
necessarily been applied to all endpoints of each individual compound 
in the category of substances.
    The Danish EPA has made extensive use of QSARs and has developed a 
QSAR database that contains predicted data on more than 166,000 
substances (OSPAR Commission, 2000; Ex. #69). A recent publication from 
the Danish EPA reports the use of QSARs for identification of potential 
persistent, bioaccumulative and toxic (PBT) and very persistent and 
very bioaccumulative (vPvB) substances from among the HPV and medium-
production volume chemicals in the EU.
    OSHA is considering using a combination of chemical group 
approaches to evaluate multiple chemicals with similar attributes

[[Page 61408]]

utilizing limited data that can be extrapolated across categories. The 
Agency invites comment on how such grouping approaches have been used 
to evaluate risks to worker populations.
    Question V.A.3: Are QSAR, read-across, and trend analysis useful 
and acceptable methods for developing hazard information utilizing 
multiple data sets for a specific group of chemicals?
    Question V.A.4: Are there other acceptable methods that can be used 
to develop hazard information for multiple chemicals within a group?
    Question V.A.5: What are the advantages and disadvantages of each 
method?
5. REACH: Registration, Evaluation, Authorization, and Restriction of 
Chemicals in the European Union (EU)
    Safe chemical management is a universal concern. The European 
Union, recognizing the need for a more integrated approach to chemical 
management, adopted REACH (Registration, Evaluation, Authorization, and 
Restriction of Chemicals) to address chemicals throughout their life 
cycle. Although REACH applies to European Union Member States, chemical 
manufacturers in other countries exporting to European countries also 
have to comply with the REACH requirements to sell their products in 
Europe.
    The REACH Regulation (EC) No 1907/2006 became effective on June 1, 
2007, and relies on the generation and disclosure of data by 
manufacturers and importers of chemicals in order to protect human 
health and the environment from chemical hazards. The regulation also 
established the European Chemicals Agency (ECHA) to coordinate 
implementation (EC 1907/2006, 2006; Ex. #70).
    REACH establishes processes for the Registration, Evaluation, 
Authorization, and Restriction of Chemicals. REACH requires 
manufacturers and importers to register their chemicals and establish 
procedures for collecting and assessing information on the properties, 
hazards, potential risks and uses of their chemicals. The registration 
process, which began in 2010, is being phased-in based on the tonnage 
and hazard classification of the substances. For existing chemicals, it 
is set to be completed in June 2018.
    For each chemical manufactured or imported in quantities of 1 ton 
or more per year, companies must register the substance by providing a 
technical dossier to ECHA. The technical dossier includes information 
on: Substance identity; physicochemical properties; mammalian toxicity; 
ecotoxicity; environmental fate; manufacture and use; and risk 
management measures (ECHA, 2012b; Ex. #71). Non-confidential 
information from the technical dossiers is published on the ECHA Web 
site (ECHA, 2012c; Ex. #72).
    Companies manufacturing or importing a chemical in quantities of 10 
or more tons per year must also conduct a chemical safety assessment. 
This assessment includes the evaluation of: (1) Human health hazards; 
(2) physicochemical hazards; (3) environmental hazards; and (4) 
persistent, bioaccumulative and toxic (PBT), and very persistent and 
very bioaccumulative (vPvB) potential (ECHA, 2012b; Ex. #71). If a 
substance is determined to be hazardous or a PBT/vPvB, registrants must 
then conduct an exposure assessment, including the development of 
exposure scenario(s) (ES) and exposure estimation, and a risk 
characterization that includes development of a health effects 
benchmark, such as the Derived No Effect Level (DNEL).
    An exposure scenario, the main output of the exposure assessment 
process, documents a set of operational conditions and risk management 
measures for a specific use of a substance. A number of exposure 
estimation models have been developed in the EU to help the regulated 
community create these exposure scenarios. Exposure scenarios must also 
be included in the Safety Data Sheets (SDS) in order to communicate 
this information down the supply chain. When an extended SDS with 
exposure scenarios is received by a chemical user, the exposure 
scenarios must be reviewed to determine if they are applicable to the 
use situation in that facility. If the exposure scenarios are 
applicable, the user has 12 months to implement them. If they are not, 
the user has several options to choose from to determine appropriate 
controls. These options include: (1) User informing supplier of their 
use, and user convincing supplier to recognize it as an ``identified 
use'' on suppliers safety assessment; (2) user implementing the 
suppliers conditions of use described in the exposure scenario of the 
original/current safety assessment; (3) user substituting the substance 
for another substance that is covered in a pre-existing safety 
assessment; (4) user finding another supplier who does provide an 
exposure scenario that covers the use of the substance; or (5) prepare 
a downstream user chemical safety report. (ECHA, 2012c; Ex. #72).
    After completing the exposure assessment, registrants conduct a 
risk characterization process to determine if the operational 
conditions cause exposures that require risk management measures to 
ensure risks of the substance are controlled. Risk characterization 
consists of the comparison of exposure values derived from each 
exposure scenario with their respective DNEL or an analogous health 
benchmark such as Derived Minimal Effect Level (DMEL) or Predicted No 
Effect Concentration (PNEC)), established by the registrant. Where no 
health benchmark is available, a qualitative risk characterization is 
required (ECHA, 2009; Ex. #73).
    Manufacturers and importers are required to document the 
information developed during the chemical safety assessment in a 
chemical safety report, which is submitted to ECHA. The report then 
forms the basis for other REACH processes, including substance 
evaluation, authorization, and restriction.
    ECHA and the EU Member States then evaluate the information 
submitted during the registration process to examine the testing 
proposals, check the quality of the registration dossiers, and evaluate 
whether a substance constitutes a risk to human health or the 
environment. Following the evaluation process, registrants may be 
required to comply with additional actions to address concerns (i.e., 
submit further information, proceed on restriction or authorization 
procedures under REACH, take actions under other legislation, etc.). 
(ECHA, 2012d; Ex. #74).
    As the implementation of REACH continues, large amounts of 
information will be generated by manufacturers, importers, and 
downstream users throughout the registration, authorization, and 
restriction processes. Some of this information is publicly available 
on ECHA Web sites, and includes toxicological information, general 
exposure control recommendations, and assessments of the availability 
of alternatives. The generation and availability of this extensive data 
on chemicals can assist OSHA, as well as U.S. employers and workers, to 
further enhance chemical safety and health management by assisting in 
the assessment of hazards, development of exposure control 
recommendations, and selection of substitutes to help drive the 
transition to safer chemicals in the workplace.
    As of July, 2013, the REACH database of registered substances is 
comprised of more than 9900 substances. The database provides extensive 
information to the public from dossiers prepared by chemical 
manufacturers, importers, and downstream users. OSHA is interested

[[Page 61409]]

in determining whether some information developed and submitted under 
REACH may be helpful to OSHA in its own regulatory initiatives. 
Information submitted under REACH's requirements to assess chemical 
risks in workplaces may be useful in developing task-based exposure 
control plans, or of use in OSHA's feasibility analyses. OSHA is 
participating in high-level discussions with the EU about the 
feasibility of sharing these data.
    Question V.A.6: OSHA is interested in the experiences of companies 
that have had to prepare chemical dossiers and submit registration 
information to the European Chemicals Agency (ECHA) ECHA. In 
particular, how might the approaches be used to support occupational 
exposure assessments and development of use-specific risk management in 
the United States?
    Question V.A.7: To what extent is information developed under REACH 
used by U.S. businesses to promote product stewardship and ensure safe 
use of substances and mixtures by product users?
    Question V.A.8: Should OSHA pursue efforts to obtain data from ECHA 
that companies are required to provide under REACH?

B. Non-OEL Approaches to Chemical Management

    OSHA's PELs and its corresponding hierarchy of controls have been a 
major focus in the fields of occupational health and industrial hygiene 
for many years. Undoubtedly, occupational exposure limits (OELs), which 
help reduce workers' risk of adverse health by establishing precise 
targets for employers to follow, will always be an essential part of 
controlling chemical exposures in workplaces. However, regardless of 
whether a more effective process for updating OSHA's PELs can be 
established, the rapid development of new chemical substances and 
mixtures that will continue to leave workers exposed to thousands of 
unregulated substances make it impractical to solely rely on OELs. 
Moreover, for many of the chemicals and mixtures that have been 
developed since the PELs were initially promulgated, insufficient 
hazard information exists to serve as a basis for developing OELs. 
While OELs generally focus on a single chemical, workers are typically 
exposed to mixtures or multiple substances in the workplace. Mixed 
exposures may also result in synergistic or antagonistic effects that 
are rarely considered in developing OELs.
    Workplace risk assessments, and corresponding risk management 
plans, should be based on an evaluation of all hazards present--OELs 
established for a few chemicals among the many in the workplace 
environment have diminished impact in these situations. Unlike OELs, 
which are only useful in protecting workers if regular measurement and 
assessment of compliance is completed, alternative risk management 
approaches focus more on determining what types of controls are 
required to reduce exposures without necessarily referring to 
quantitative assessments of exposure to evaluate success.
    An important aspect of risk assessment and risk management is 
consideration of safer alternatives, which can often result in a path 
forward that is less hazardous, technically feasible, and economically 
viable.
1. Informed Substitution to Safer Chemicals and Processes
    While establishing exposure limits for hazardous chemicals helps to 
reduce workers' risk of adverse health effects, the process is costly, 
time consuming, and does not drive the development or adoption of safer 
alternatives that could best protect workers. OSHA recognizes that 
ultimately, an approach to chemical management that incentivizes and 
spurs the transition to safer chemicals, products, and processes in a 
thoughtful, systematic way will most effectively ensure safe and 
healthful conditions for workers.
    Informed substitution, the considered transition from hazardous 
chemicals to safer substances or non-chemical alternatives, provides a 
way of moving toward a more preventative chemical management framework.
a. Substitution in Practice
    Whenever a hazardous chemical is regulated, there is always the 
potential for the chemical to be replaced with a substitute chemical or 
redesigned product or process that poses new and potentially greater 
hazards to workers, consumers, or the environment or results in risk-
shifting from one group to another. Regrettably, this potential has 
been realized in a number of cases. For example:
     The regulation of methylene chloride by EPA, FDA, and OSHA 
spurred the shift to 1-bromopropane, an unregulated neurotoxicant and 
possible carcinogen, in a variety of applications, such as 
refrigeration, metal cleaning, and vapor and immersion degreasing 
applications, as well as in adhesive resins (Kriebel et al., 2011; Ex. 
#75).
     Air quality regulations in California created a market in 
the vehicle repair industry for solvent products formulated with n-
hexane, a neurotoxicant causing symptoms of peripheral neuropathy, and 
hexane-acetone blends, which amplify the neurotoxic effects of n-
hexane, thus resulting in risk-shifting from the environment to workers 
(Wilson et al., 2007; Ex. #76).
    While regulatory processes lacking a robust assessment of 
alternatives can result in substitution that is equally detrimental to 
human health or the environment, regulatory efforts that require 
planning processes and provide guidance and technical assistance on 
preferred alternatives can minimize risk trade-offs and protect 
workers, consumers, and the environment. For example, in Massachusetts, 
facilities using specific toxic chemicals in certain quantities are 
required to undertake a toxics use reduction planning process. Agencies 
provide various resources to encourage and facilitate the voluntary 
adoption of alternatives. In the case of trichloroethylene, the 
Massachusetts Office of Technical Assistance and the Toxics Use 
Reduction Institute provided technical assistance, educational 
workshops, a database of safer alternatives, and performance 
evaluations of alternatives (Toxics Use Reduction Institute, 2011a; Ex. 
#78; Toxics Use Reduction Institute, 2011b; Ex. #79; Toxics Use 
Reduction Institute, 2011c; Ex. #80). Through these efforts, 
Massachusetts companies reduced the use of trichloroethylene by 77 
percent since 1990, moving to a number of safer alternatives in the 
process (Toxics Use Reduction Institute, 2011d; Ex. #81).
    These cases demonstrate that the transition to safer chemicals, 
materials, products, and processes will be best facilitated not through 
restrictions or bans of chemicals, but rather through the integration 
of informed substitution and guidance on preferred alternatives into 
regulatory efforts.
b. Benefits of a Preference for Primary Prevention Strategies
    The reduction or elimination of a hazard at the source, as 
traditionally embraced by health and safety professionals, is not only 
the most reliable and effective control approach, but also provides a 
number of benefits for workers and businesses.
    Preferring primary prevention strategies (i.e. elimination and 
substitution) can result in the ``total elimination of exposure to 
hazardous chemicals, less reliance on worker compliance or equipment 
maintenance for success, elimination of the potential for accidental or 
non-routine overexposures, prevention of dermal exposures, and process 
and environmental improvements not

[[Page 61410]]

related to worker health'' (Roelofs et al., 2003; Ex. #82).
    Additionally, making process improvements designed to reduce or 
eliminate workers' exposures to hazardous chemicals often results in 
significant business improvements or savings. A 2008 study by the 
American Industrial Hygiene Association (AIHA) demonstrated the 
relationship between the application of the hierarchy of controls and 
financial benefits. The study found that the greatest cost savings and 
other benefits tended to be associated with hazard elimination and the 
elimination of personal protective equipment (PPE) usage. It also 
highlighted the ability of material substitution to result in very 
large payoffs due to the creation of efficiencies throughout the 
business process (American Industrial Hygiene Association, 2008; Ex. 
#83). For example:
     A foundry making automatic diesel engine blocks enhanced 
and aggressively enforced a purchasing specification program to 
eliminate supplied scrap metal contaminated with lead. By eliminating 
lead from its supply chain, the company not only achieved high levels 
of employee protection, but also enhanced the quality of its products 
and realized nearly $20 million in savings for the facility.
     An aircraft manufacturing company, struggling to comply 
with the OSHA PEL for hexavalent chromium, transitioned from chromate-
based primers to non-chromate based primers, resulting not only in the 
elimination of worker exposure to chromate dusts from rework sanding, 
but also in quality improvements of its products, increased customer 
satisfaction, productivity gains, avoidance of costly changes to their 
exhaust ventilation system, and a savings of $504,694 over the 5-year 
duration of the project.
c. Informed Substitution
    In order to truly protect workers from chemical hazards, it is 
important that OSHA not only develop health standards for hazardous 
chemicals, but also understand alternatives to regulated chemicals and 
support a path forward that is less hazardous, technically feasible, 
and economically viable. Informed substitution provides a framework for 
meeting this goal.
    As previously described, informed substitution is the considered 
transition from a potentially hazardous chemical, material, product, or 
process to safer chemical or non-chemical alternatives. The goals of 
informed substitution are to minimize the likelihood of unintended 
consequences, which can result from a precautionary switch away from a 
hazardous chemical without fully understanding the profile of potential 
alternatives, and to enable a course of action based on the best 
information that is available or can be estimated. Informed 
substitution approaches focus on identifying alternatives and 
evaluating their health, safety, and environmental hazards, potential 
trade-offs, and technical and economic feasibility.
    Substitution is not limited to substitution of one chemical with 
another. It can also occur at the production process or product level. 
At the product level, substitution may involve a design change that 
takes advantage of the characteristics of new or different materials. A 
chemical process design change may eliminate several production steps 
thereby avoiding or reducing the use of high hazard chemicals. In some 
cases, a particular chemistry or the function it serves may be 
determined to be unnecessary.
    As implementation of chemical substitution and product and process 
changes can be quite complicated, a variety of processes, tools, and 
methods are critical to achieving informed substitution.
    Substitution planning, similar to facility planning for pollution 
prevention and source reduction, establishes practical steps for 
evaluating substitution as a workplace risk reduction measure. This 
type of planning process supports informed substitution by encouraging 
chemical users to: Systematically identify hazardous chemicals; set 
goals and priorities for the elimination or reduction of hazardous 
chemicals; evaluate alternatives; identify preferred alternatives; and 
promote the adoption of identified alternatives.
    Alternatives assessment is a process of identifying and comparing 
potential chemical and non-chemical alternatives that could replace 
chemicals or technologies of concern on the basis of their hazards, 
performance, and economic viability. A variety of alternatives 
assessment processes have been developed to date (Lavoie et al., 2010; 
Ex. #84; Toxics Use Reduction Institute, 2006; Ex. #85; Rossi et al., 
2006; Ex. #86; Raphael et al., 2011; Ex. #87). Various tools and 
methods have been developed to evaluate hazard, performance, and cost 
when assessing alternatives. For example, comparative chemicals hazard 
assessments compare potential alternatives based on a variety of hazard 
endpoints in order to select a safer alternative. Some examples of 
comparative chemicals hazard assessment tools include the GreenScreen 
(Clean Production Action, 2012; Ex. #88) and Design for the Environment 
(DfE) Safer Product Labeling Program (U.S. EPA, 2011a; Ex. #89). Other 
existing methods for chemical comparison include the Column Model 
(Institut f[uuml]r Arbeitsschutz der Deutschen Gesetzlichen 
Unfallversicherung, 2011; Ex. #90) and QuickScan (Netherlands Ministry 
of Infrastructure and the Environment, 2002; Ex. #91). Tools and 
methods for evaluating performance and cost attributes, while less well 
developed, are also critical for the selection of a preferred 
alternative.
d. Substitution at OSHA
    Substitution is not new for OSHA. Historically, OSHA attempted to 
encourage substitution by setting a ``no occupational exposure level'' 
for certain potential carcinogens where suitable substitutes that are 
less hazardous to humans existed for particular uses (45 FR 5257-58; 
Ex. #92). Although this requirement was never fully implemented, the 
final rule detailed a process for the Agency to analyze the feasibility 
of substitutes, which required the consideration of: (1) the safety of 
the substitute, including the comparative acute and chronic toxicity of 
the carcinogenic chemical and the substitute, and other relevant 
factors, such as environmental factors; (2) the technical feasibility 
of the substitute, including its relative effectiveness; and (3) the 
economic cost of substitution (45 FR 5258; Ex. #92, 29 CFR 1990.111(k); 
Ex. #93, see also 1990.132(b)(6); Ex. #94, 1990.146(k); Ex. #95).
    OSHA health standards also identify substitution as a preferred 
exposure control. For example, in the 1989 Air Contaminants Standard, 
the Agency refers to substitution, when properly applied, as ``a very 
effective control technique'' and ``the quickest and most effective 
means of reducing exposure'' (54 FR 2727, 2789; Ex. #7). In addition, 
the Agency's respiratory protection standard mandates the use of 
accepted engineering control measures, including the substitution of 
less toxic materials, as far as feasible, before using respirators to 
control occupational diseases caused by breathing contaminated air (29 
CFR 1910.134(a); Ex. #96). Despite this, when complying with PELs and 
other health standards in practice, employers are required to select 
and implement administrative or engineering controls before using 
personal protective equipment, but are not specifically required or 
encouraged to consider elimination or substitution

[[Page 61411]]

before other engineering or administrative controls. (See 29 CFR 
1910.1000(e); Ex. #97). Thus, substitution may be often overlooked in 
favor of other approaches, such as ventilation and isolation, when 
employers are controlling exposures to hazardous chemicals.
    OSHA also considers substitution during the development of PELs. 
While OSHA does not solely rely on substitution to make its required 
feasibility findings (62 FR 1494, 1576; Ex. #98; 71 FR 10099, 10260; 
Ex. #99), the Agency, as part of PEL rulemaking efforts, develops and 
evaluates information about substitution in its technological and 
economic feasibility analysis, highlighting options available for 
eliminating or reducing the regulated chemical's use in various 
industries and applications. For example, the feasibility analysis for 
methylene chloride describes numerous substitute chemicals and 
processes, including a detailed table of substitute paint removal 
methods for 16 applications, and evaluates the relative risks for seven 
of the more common substitutes for methylene chloride (OSHA, 1996; Ex. 
#100). However, the analysis of substitutes has varied widely from 
regulation to regulation. For example, the feasibility analysis for 
hexavalent chromium identifies specific substitute chemicals and 
processes in many industries, but does not discuss the health or safety 
hazards of the substitutes (OSHA, 2006a; Ex. #101), while the 
feasibility analysis for formaldehyde includes only a mention of the 
availability of one identified substitute for a few industry sectors 
(OSHA, 1987; Ex. #102) and the feasibility analysis for ethylene oxide 
does not contain any discussion of substitutes (OSHA, 1984; Ex. #103).
    OSHA has also included information on substitutes in a variety of 
non-regulatory documents. New information about available substitutes 
and substitution trends is included in lookback reviews of existing 
standards conducted by the Agency (e.g., lookback review of the 
ethylene oxide standard, lookback review of the methylene chloride 
standard) (OSHA, 2005; Ex. #104; OSHA, 2010; Ex. #105). In some cases, 
OSHA has also developed information on substitution, even where a PEL 
has not been established. For example, the OSHA guidance document on 
the best practices for the safe use of glutaraldehyde in health care 
includes information about drop-in replacements and alternative 
processes available to reduce or eliminate the use of the chemical 
(OSHA, 2006b; Ex. #106).
    In October 2013, OSHA launched an effort to encourage employers, 
workers, and unions to proactively reduce the use of hazardous 
chemicals in the workplace and achieve chemical use that is safer for 
workers and better for business. As part of this effort, the Agency 
developed a web toolkit that guides employers and workers in any 
industry through a seven-step process for transitioning to safer 
chemicals (OSHA, 2013a; Ex. #107). Each step contains information, 
resources, methods, and tools that will help users eliminate hazardous 
chemicals or make informed substitution decisions in the workplace by 
finding a safer chemical, material, product, or process.
e. Possible Opportunities for Integrating Informed Substitution 
Approaches Into OSHA Activities
    There are a variety of existing regulatory and non-regulatory 
models for incorporating informed substitution into chemical management 
activities. The following are some examples of entities that have 
developed and utilized informed substitution approaches as part of 
regulatory efforts; guidance and policy development; education, 
training, and technical assistance activities; and data development and 
research efforts.
i. Models for Regulatory Approaches
    Some regulations and voluntary standards require risk reduction 
through the implementation of a hierarchy of controls that clearly 
delineates elimination and substitution as preferred options to be 
considered and implemented, where feasible, before other controls. For 
example, the ANSI/AIHA Z10-2005 standard for Occupational Health and 
Safety Management Systems, a voluntary national consensus standard, 
requires organizations to implement and maintain a process for 
achieving feasible risk reduction based upon the following preferred 
order of controls: A. Elimination; B. Substitution of less hazardous 
materials, processes, operations, or equipment; C. Engineering 
controls; D. Warnings; E. Administrative Controls; and F. Personal 
protective equipment (ANSI/AIHA Z10-2005, 2005; Ex. #108). European 
Union Directives 98/24/EC and 2004/37/EC require employers to eliminate 
risks by substitution before implementing other types of protection and 
prevention measures (98/24/EC, 1998; Ex. #109, 2004/37/EC, 2004; Ex. 
#110).
    Some existing laws require firms to undertake planning processes 
for the reduction of identified hazardous chemicals. For example, the 
Massachusetts Toxics Use Reduction Act requires entities that use 
listed hazardous chemicals in certain quantities to undertake a 
planning process for reducing the use of those chemicals (Massachusetts 
Department of Environmental Protection, n.d.; Ex. #77).
    Existing regulations in the European Union place a duty on 
employers to replace the use of certain hazardous chemicals with safer 
substitutes, if technically possible. For example, Directive 2004/37/EC 
requires the substitution of carcinogens and mutagens with less harmful 
substances where technically feasible (2004/37/EC, 2004) and Directive 
98/24/EC requires employers to ensure that risks from hazardous 
chemical agents are eliminated or reduced to a minimum, preferably by 
substitution (98/24/EC, 1998; Ex. #109).
    Other regulations require the use of acceptable substitutes where 
the uses of certain hazardous chemicals are phased-out. This type of 
approach is currently implemented by U.S. EPA in the context of 
phasing-out ozone depleting substances. The Clean Air Act requires that 
these substances be replaced by others that reduce risks to human 
health and the environment. Under the Significant New Alternatives 
Policy (SNAP) program, EPA identifies and publishes lists of acceptable 
and unacceptable substitutes for ozone-depleting substances (Safe 
Alternatives Policy, 2011; Ex. #111).
    Some chemical management frameworks require the assessment of 
substitutes before making decisions to limit or restrict the use of a 
hazardous chemical. For example, the European Union REACH Regulation 
(Registration, Evaluation, Authorization and Restriction of Chemicals) 
requires that an analysis of alternatives, the risks involved in using 
any alternative, and the technical and economic feasibility of 
substitution be conducted during applications of authorization for 
substances of very high concern (EC 1907/2006, 2006; Ex. #70).
    Other efforts to spur the transition to safer chemicals, products, 
and processes are based on the development of criteria-based standards 
for functions or processes that rely on hazardous chemicals. For 
example, the EPA DfE Safer Product Labeling Program is a nonregulatory 
program that recognizes safe products using established criteria-based 
standards. In order to receive DfE recognition, all chemicals in a 
formulated product must meet Master Criteria (i.e., toxicological 
thresholds for attributes of concern, including: acute

[[Page 61412]]

mammalian toxicity; carcinogenicity; genetic toxicity; neurotoxicity; 
repeated dose toxicity; reproductive and developmental toxicity; 
respiratory sensitization; skin sensitization; environmental toxicity 
and fate; and eutrophication), as well as relevant functional-class 
criteria (i.e., additional toxicological thresholds for attributes of 
concern for surfactants, solvents, direct-release products, fragrances, 
and chelating and sequestering agents), established by the EPA (U.S. 
EPA, 2011a; Ex. #89).
    While there are a number of ways in which OSHA could consider 
integrating substitution and alternatives assessment into its 
regulatory efforts, the Agency, in order to promulgate any such 
standard, would need to make the significant risk, technological 
feasibility, and economic feasibility findings required under the OSH 
Act. However, even without regulation, it is important to consider 
voluntary models for incorporating informed substitution into chemical 
management activities.
ii. Models for Guidance Development
    Some entities have developed guidance to promote the transition to 
safer alternatives. The European Union, in order to support legislative 
substitution mandates, developed guidance on the process of 
substitution, including setting goals, identifying priority chemicals, 
evaluating substitutes, selecting safer alternatives, and implementing 
chemical, material, and process changes. The guidance establishes and 
describes a seven step substitution framework, providing workplaces 
with a systematic process for evaluating chemical risk and identifying 
chemicals that could or should be substituted (European Commission, 
2012; Ex. #113). The steps include: Assessing the current level of 
risk; deciding on risk reduction needs; assessing the margins of 
change; looking for alternatives; checking the consequences of a 
change; deciding on change; and deciding on how and when to implement 
change.
    Similarly, the German Federal Institute for Occupational Safety and 
Health (BAuA) established guidance to support the employer's duty, as 
mandated in the German Hazardous Substances Ordinance, to evaluate 
substitutes to hazardous substances and implement substitution where 
less hazardous alternatives are identified (German Federal Institute 
for Occupational Safety and Health, 2011; Ex. #114). The guidance, TRGS 
600, includes a framework for identifying and evaluating substitutes 
and establishes criteria for assessing and comparing the health risks, 
physicochemical risks, and technical suitability of identified 
alternatives (German Federal Institute for Occupational Safety and 
Health, 2008; Ex. #115).
    The German Environment Agency has also developed guidance on 
sustainable chemicals. The guide assists manufacturers, formulators, 
and end users of chemicals in the selection of sustainable chemicals by 
providing criteria to distinguish between sustainable and non-
sustainable substances (German Environment Agency, 2011; Ex. #116).
    OSHA considered developing guidance on safer substitutes to 
accompany individual chemical exposure limit standards in its 2010 
regulatory review of methylene chloride. Due to the increased use of 
other hazardous substitutes after methylene chloride was regulated in 
1998, the Agency considered establishing guidance recommending that 
firms check the toxicity of alternatives on the EPA and NIOSH Web sites 
before using a substitute (OSHA, 2010; Ex. #105).
iii. Models for Education, Training, and Technical Assistance
    Other entities have developed outreach, training, and technical 
assistance efforts for substitution planning and the assessment of 
substitutes for regulated chemicals. The Massachusetts Toxics Use 
Reduction Act, which established a number of structures to assist 
businesses, provides a good example of such efforts. The Massachusetts 
Office of Technical Assistance and Technology (OTA) provides compliance 
assistance and on-site technical support that helps facilities use less 
toxic processes and boost economic performance. The Massachusetts 
Toxics Use Reduction Institute provides training, conducts research, 
and performs alternatives assessments in order to educate businesses on 
the existence of safer alternatives and promote the on-the-ground 
adoption of these alternatives. Toxics Use Reduction Planners (TURPs), 
certified by the Massachusetts Department of Environmental Protection 
(MA DEP), prepare, write and certify the required toxics use reduction 
plans and are continually educated about best practices in toxics use 
reduction. Taken together, these services provide a robust resource for 
regulated businesses on the transition to safer alternatives 
(Massachusetts Department of Environmental Protection, n.d.; Ex. #77).
iv. Models for Data Development
    Several efforts, at both the federal and international levels, 
attempt to support the transition to safer alternatives through 
research and data development. For example, EPA, in collaboration with 
the non-governmental organization GreenBlue and industry stakeholders, 
jointly developed a database of cleaning product ingredient chemicals 
(surfactants, solvents, fragrances, and chelating agents) that meet 
identified environmental and human health criteria (GreenBlue, 2012; 
Ex. #117). In Spain, the Institute of Work, Environment, and Health 
(ISTAS) has developed a database that is a repository of information on 
substitute chemicals. The database can be searched for chemical 
substances, uses/products, processes, or sectors to display information 
on substitutes and hazards associated with those substitutes (ISTAS, 
2012; Ex. #118). In addition, the European Union SUBSPORT project has 
begun to create a Substitution Support Portal, a state-of-the-art 
resource on safer alternatives to the use of hazardous chemicals. The 
resource is intended to provide not only information on alternative 
substances and technologies, but also tools and guidance for substance 
evaluation and substitution management (SUBSPORT, 2012; Ex. #119).
    Other efforts focus on the completion of alternatives assessments 
for priority chemicals and uses. Currently, EPA's Design for the 
Environment Program, as well as the Massachusetts Toxics Use Reduction 
Institute, has conducted alternatives assessments for priority 
chemicals and functional uses, making this information publicly 
available in the process (U.S. EPA, 2012c; Ex. #120; Toxics Use 
Reduction Institute, 2006; Ex. #85).
    In addition, some research efforts attempt to fill data gaps with 
regards to the toxicological properties of existing chemicals. While 
some efforts to conduct toxicity testing for chemicals is taking place 
at the federal level (U.S. EPA, 2011b; Ex. #121, U.S. EPA, 2012d; Ex. 
#122), there have not been systematic efforts to conduct targeted 
toxicology studies for specific substitutes of interest.
    Question V.B.1: To what extent do you currently consider 
elimination and substitution for controlling exposures to chemical 
hazards?
    Question V.B.2: What approaches would most effectively encourage 
businesses to consider substitution and adopt safer substitutes?
    Question V.B.3: What options would be least burdensome to industry,

[[Page 61413]]

especially small businesses? What options would be most burdensome?
    Question V.B.4: What information and support do businesses need to 
identify and transition to safer alternatives? What are the most 
effective means to provide this information and support?
    Question V.B.5: How could OSHA leverage existing data resources to 
provide necessary substitution information to businesses?
v. Effectively Implementing Informed Substitution Approaches
    The goals of informed substitution cannot be achieved without the 
development and application of tools and methods for identifying, 
comparing, and selecting alternatives. Existing tools and methods range 
in complexity, from quick screening tools to detailed comparative 
hazard assessment methodologies to robust frameworks for evaluating 
alternatives based on hazard, performance, and economic feasibility. 
Illustrative examples, which represent the range of tools available, 
are described below.
    Some assessment tools provide methods for rapid evaluation of 
chemical hazards based on readily available information. These types of 
tools are critical for small and medium-sized businesses, which often 
lack resources and expertise to evaluate and compare chemical hazards. 
In the state of Washington, the Department of Ecology (DOE) has 
developed the Quick Chemical Assessment Tool (QCAT) to allow businesses 
to identify chemicals that are not viable alternatives to a chemical of 
concern by assigning an appropriate grade for the chemical based on 
nine high priority hazard endpoints (Washington Department of Ecology, 
2012; Ex. #123). Similarly, the Institute for Occupational Safety and 
Health of the German Federation of Institutions for Statutory Accident 
Insurance and Prevention (IFA) developed the Column Model as a tool for 
businesses to evaluate chemicals based on six hazard categories using 
information obtained from chemical safety data sheets (IFA, 2011; Ex. 
#90).
    Other existing tools provide more detailed methodologies for 
conducting a comparative hazard assessment, which require greater 
expertise, data, and resources to complete. The GreenScreen, created by 
Clean Production Action, provides a methodology for evaluating and 
comparing the toxicity based on nineteen human and environmental hazard 
endpoints, assigning a level of concern of high, moderate, or low for 
each endpoint based on various established criteria (Clean Production 
Action, 2012; Ex. #88).
    A number of robust frameworks have also been developed to assess 
the feasibility of adopting alternatives for hazardous chemicals based 
on environmental, performance, economic, human health, and safety 
criteria. The Massachusetts Toxics Use Reduction Institute developed 
and implemented a methodology for assessing alternatives to hazardous 
chemicals based on performance, technical, financial, environmental, 
and human health parameters (TURI, 2006; Ex. #85). Similarly, the U.S. 
EPA DfE program has also developed and implemented an alternatives 
assessment framework to characterize alternatives based on the 
assessment of chemical hazards as well as the evaluation of 
availability, functionality, economic, and life cycle considerations 
(Lavoie et al., 2010; Ex. #84, U.S. EPA, 2012c; Ex. #120).
    Although some tools and methods exist, as discussed above, further 
research and development in this area is critical for the effective 
implementation of informed substitution.
    Question V.B.6: What tools or methods could be used by OSHA and/or 
employers to conduct comparative hazard assessments? What criteria 
should be considered when comparing chemical hazards?
    Question V.B.7: What tools or methods could be used by OSHA and/or 
employers to evaluate and compare the performance and cost attributes 
of alternatives? What criteria should be considered when evaluating 
performance and cost?
2. Hazard Communication and the Globally Harmonized System (GHS)
    OSHA promulgated its Hazard Communication Standard (HCS) (29 CFR 
1910.1200; Ex. #124) in 1983 to require employers to obtain and provide 
information to their employees on the hazards associated with the 
chemicals used in their workplaces. After thirty years of 
implementation, the HCS has resulted in extensive information being 
disseminated in American workplaces through labels on containers, 
safety data sheets (SDSs), and worker training programs.
    On March 26, 2012, OSHA published major modifications to the HCS. 
(77 FR 17574-17896; Ex. #125). These modifications are being phased in 
over several years, and will be completely implemented in June 2016. 
Referred to as HazCom 2012, the revised rule incorporates a new 
approach to assessing the hazards of chemicals, as well as conveying 
information about them to employees. The revised rule is based on the 
United Nations' Globally Harmonized System for the Classification and 
Labeling of Chemicals (GHS), which established an international, 
harmonized approach to hazard communication.
    The original HCS was a performance-oriented rule that prescribed 
broad rules for hazard communication but allowed chemical manufacturers 
and importers to determine how the information was conveyed. In 
contrast, HazCom 2012 is specification-oriented. Thus, while the HCS 
requires chemical manufacturers and importers to determine the hazards 
of chemicals, and prepare labels and safety data sheets (SDSs), HazCom 
2012 goes further by specifying a detailed scheme for hazard 
classification and prescribing harmonized hazard information on labels. 
In addition, SDSs must follow a set order of information, and the 
information to be provided in each section is also specified.
    Hazard classification means that a chemical's hazards are not only 
identified, they are characterized in terms of severity of the effect 
or weight of evidence for the effect. Thus, the assessment of the 
hazard involves identifying the ``hazard class'' into which a chemical 
falls (e.g., target organ toxicity), as well as the ``hazard 
category''--a further breakdown of the hazardous effect generally based 
on either numerical cut-offs, or an assessment of the weight of the 
evidence. For target organ toxicity, for example, chemicals for which 
there is human evidence of an effect are likely to be classified under 
Category 1, the most hazardous category, thus indicating the highest 
classification for the effect. If the only data available are animal 
studies, the chemical may fall in Category 2--still potentially 
hazardous to humans, but lower in terms of the weight of evidence for 
the effect. Table-I illustrates how such a chemical hazard 
classification may be assigned by hazard class and hazard category

[[Page 61414]]

[GRAPHIC] [TIFF OMITTED] TP10OC14.001

    The process of classifying chemicals under HazCom 2012 means that 
all chemicals will be fully characterized as to their hazards, as well 
as degree of hazardous effect, using a standardized process with 
objective criteria. Thus, OSHA could use this system to select certain 
hazard classes and categories to set priorities. For example, the 
Agency could decide to identify substances that are characterized as 
Class 1 Carcinogens or as Reproductive Toxicants as its priorities. 
Then chemicals that fall into those hazard categories could be further 
investigated to determine other relevant factors, such as numbers of 
employees exposed, use of the chemical, risk assessment, etc. The 
HazCom 2012 information could lead to a more structured and consistent 
priority system than previously attempted approaches. (Ex. #126) OSHA 
could also investigate whether the hazard categories lend themselves to 
establishing regulatory provisions for hazard classes and categories 
rather than for individual substances. The availability of specific 
hazard categorization for chemicals could allow this to be done on a 
grouping basis--either in regulation, or in guidance.
    Once a chemical is placed into a hazard class and hazard category, 
HazCom 2012 (and the GHS) specifies the harmonized information that 
must appear on the label. Referred to as ``label elements,'' these 
include a pictogram, signal word, hazard statement(s), and 
precautionary statement(s). In addition, the label must have a product 
identifier and supplier contact information. The use of standardized 
label elements will help to ensure consistency and comprehensibility of 
the information, which will make HazCom 2012 more effective in terms of 
conveying information to employees and employers. The approach taken in 
the GHS strengthens the protections of the OSHA HCS in several ways, 
and introduces the possibility of the Agency using the information 
generated under HazCom 2012 to help frame a more comprehensive approach 
to ensuring occupational chemical safety and health.
3. Health Hazard Banding
    ``Health hazard banding'' can be defined as a qualitative framework 
to develop occupational hazard assessments given uncertainties caused 
by limitations in the human health or toxicology data for a chemical or 
other agent. Health hazard banding presumes it is possible to group 
chemicals or other agents into categories of similar toxicity or hazard 
characteristics.
    Health hazard banding assigns chemicals with similar toxicities 
into hazard groups (or bands. The occupational health professional can 
use this classification or hazard band, along with information on 
worker exposures to the substance, to do exposure risk assessment. 
Hazard banding, along with exposure information, is a useful risk 
assessment tool, particularly in situations where toxicity data are 
sparse. Hazard banding can also aid in the prioritization and hazard 
ranking of chemicals in the workplace. NIOSH is working with OSHA and a 
variety of stakeholder groups (federal agencies, industry, labor 
organizations, and professional associations) to develop guidance on 
establishing the technical criteria, decision logic, and minimum 
dataset for the hazard band process.
4. Occupational Exposure Banding
    NIOSH has proposed an approach, occupational exposure banding, 
which would sort chemicals into five bands (A

[[Page 61415]]

through E), with each band representing a different hazard level. 
Chemicals with the lowest toxicity would be grouped in Band A, while 
the moist toxic chemicals would be grouped in Band E. The proposed 
process includes a three-tiered evaluation system based on the 
availability of toxicological data to define a range of concentrations 
for controlling chemical exposures. A Tier 1 evaluation relies on 
hazard codes and categories from GHS, and intended for chemicals for 
which little information exists. Therefore, a chemical in Band D or E 
in the Tier 1 process is a bad actor and should be targeted for 
elimination and or substitution. Tier 2 and 3 require professional 
expertise. Once NIOSH completes their validation work of the three 
tiers, they plan to develop tools to facilitate evaluating hazard data 
and assigning chemicals to hazard bands as well as educational 
materials for health and safety professionals, managers, and workers. 
(Exs. #127 & #128)
5. Control Banding
    Control banding is a well-established approach of using the hazard 
statements from a label and/or safety data sheet (SDS) to lead an 
employer to recommended control measures. This approach has been used 
successfully in a number of countries, particularly in Europe where 
such as system of hazard classification has been in use for some time. 
HazCom 2012 opens up the possibility that control banding can be 
further developed and refined in the U.S., either as guidance or 
regulatory provisions. It is a particularly useful way to provide 
information for small businesses to effectively control chemicals 
without necessarily going through the process of exposure monitoring 
and other technical approaches to ensuring compliance. It also will 
give employers better information to conduct risk assessments of their 
own workplaces, and thus select better control measures.
    Health hazard banding can be used in conjunction with control 
banding to use the information available on the hazard to guide the 
assessment and management of workplace risks. In fact, health hazard 
banding is the first step in the control banding process. Control 
banding determines a control measure (for example dilution ventilation, 
engineering controls, containment, etc.) based on a range or ``band'' 
of hazards (such as skin/eye irritant, very toxic, carcinogenic, etc.), 
and exposures (small, medium, or large exposure). This approach is 
based on the fact that there are a limited number of control 
approaches, and that many chemical exposure problems have been met and 
solved before. Control banding uses the solutions that experts have 
developed previously to control occupational chemical exposures, and 
suggests them for other tasks with similar exposure situations. It 
focuses resources on exposure controls, and describes how strictly a 
risk needs to be managed.
    Control banding is a more comprehensive qualitative risk 
characterization and management strategy that goes further in assigning 
prescribed control methods to address chemical hazards. It is designed 
to allow employers to evaluate the need for exposure control in an 
operation and to identify the appropriate control strategy given the 
severity of the hazard present and magnitude of exposure. The strength 
of control banding is that it is based on information readily available 
to employers on safety data sheets (SDSs), without the need for 
exposure measurements or access to occupational health expertise 
(except in certain circumstances). Control banding involves not only 
the grouping of workplace substances into hazard bands (based on 
combinations of hazard and exposure information) but also links the 
bands to a suite of control measures, such as general dilution 
ventilation, local exhaust ventilation, containment, and use of 
personal protective equipment (PPE).
    Under control banding, one must consider the chemical's hazardous 
properties, physical properties, and exposure potential in order to 
determine the level of exposure control desired. The criteria used for 
categorizing chemicals include hazard information such as flammability, 
reactivity, and the nature of known health effects. These 
characteristics are associated with defined hazard phrases (e.g., 
``Causes severe skin burns and eye damage'' or ``Causes liver damage,'' 
or ``Reproductive hazard''). These standardized phrases have been 
familiar in the EU as ``R-phrases'' and are found on SDSs.
    Different hazard bands exist along a continuum ranging from less 
hazardous chemicals to more hazardous chemicals. Once the appropriate 
hazard group has been determined from the hazard statements (e.g., 
``Hazard Group B''), exposure potential is evaluated based on the 
quantity in use, volatility (for liquids), or particulate nature (for 
solids). After evaluating these properties and categorizing the 
chemical into hazard and exposure bands, the chemicals are matched, 
based on their band categorization, to the appropriate control 
strategy, with more stringent controls applied for substances that are 
placed in high-toxicity bands.
    The Control of Substances Hazardous to Health (COSHH) guidance 
issued by the Safety Executive (HSE) of the United Kingdom is one model 
of control banding (Health and Safety Executive, 2013; Ex. #129). Under 
the 2002 COSHH regulation, employers must conduct a risk assessment to 
decide how to prevent employees from being exposed to hazardous 
substances in the workplace. COSHH principles first require that 
exposure is prevented by employers, to the extent possible, by means 
of:
     Changing the way tasks are carried out so that exposures 
aren't necessary anymore;
     Modifying processes to cut out hazardous by-products or 
wastes; or
     Substituting a non-hazardous or less hazardous substance 
for a hazardous substance with new substances (or use the same 
substance in a different form) so that there is less risk to health.
    If exposures to hazardous substances cannot be prevented entirely, 
then COSHH requires employers to adequately control them (Control of 
Substances Hazardous to Health Regulations, 2002; Ex. #130). 
Recognizing that many small employers may not have access to the 
required expertise, and also to reduce the need for a professional and 
to promote consistency in the assessment process, the HSE developed an 
approach to assessment and control of chemical hazards using control 
banding methodologies spelled out in the 2002 regulation. This control 
banding approach is described in detail in COSHH Essentials. Employers 
may use the guidance spelled out in the COSHH Essentials guide to 
determine the appropriate control approach for the chemical hazard in 
question. Each control approach covers a range of actions that work 
together to reduce exposure: (1) General Ventilation, (2) Engineering 
Controls, (3) Containment, and lastly, (4) Special--a scenario where 
employers should seek expert advice to select appropriate control 
measures.
    The first step outlined under the COSHH Essentials guidance is to 
consult the safety data sheet for each chemical in use. Employers must 
record the date of assessment, the name of the chemical being assessed, 
the supplier of the chemical, and the task(s) for which the chemical is 
used.
    Step two involves the determination of the health hazard. Employers 
ascertain the hazard by assessing the possible health effects from the 
hazard statements provided on the SDS, the amount in use, and the 
dustiness or volatility of the chemical in use.

[[Page 61416]]

Employers reference the hazard statements found on chemical safety data 
sheets against a table of COSHH hazard groups in order to categorize 
them into the appropriate hazard group (``A'' through ``E'', and 
possibly ``S''). Chemicals in Group A tend to be regarded as less 
harmful and may, for example, cause temporary irritation. Chemicals in 
Group E are the most hazardous and include known carcinogens. Group S 
encompasses substances that have special considerations for damage 
caused via contact with the eyes or skin.
    Additionally, Step two requires employers to make some 
determinations about the quantity and physical state of chemicals in 
use. They must decide if the amount of chemical in use would be 
described as ``small'' (grams or milliliters), ``medium'' (kilograms or 
liters), or ``large'' (tons or cubic meters). When in doubt, COSHH 
Essentials principles encourage employers to err on the side of the 
larger quantity in making their determination. Additionally, the 
physical state of chemicals effect how likely they are to get into the 
air and this affects the control approach to be utilized. For solids, 
COSHH Essentials guides employers to make a determination of either 
``Low'', ``Medium'', or ``High'' dustiness based upon visible criteria 
observed during the use of these chemicals. Employers may also use 
look-up tables provided in the COSHH Essentials guide to make a 
determination of whether liquids have ``low'', ``medium'', or ``high'' 
volatility based upon the chemical's boiling point and ambient or 
process operating temperatures.
    In Step three of the COSHH Essentials guide, employers identify the 
appropriate control approach. Tables provided by the COSHH Essentials 
guide show the control approaches for hazard groups ``A'' through ``E'' 
according to quantity of chemical in use and its dustiness/volatility. 
Table-II illustrates how the control approaches are assigned. The 
control approaches referred to by number in the table are: 1) General 
Ventilation, 2) Engineering Control, 3) Containment, and 4) Special. 
(Health and Safety Executive, 2009; Ex. #131).
[GRAPHIC] [TIFF OMITTED] TP10OC14.002


[[Page 61417]]


    Additionally, the COSHH Essentials guide provides detailed control 
guidance sheets for a range of common tasks. Consultation of these 
task-specific guidance sheets constitutes Step four under COSHH 
Essentials. Step five of COSHH Essentials involves the employer 
deciding on how best to implement control measures as prescribed. COSHH 
Essentials principles also stress the importance of employers reviewing 
their assessments regularly, especially if there is a significant 
change in workplace processes or environment. Employers are encouraged 
to incorporate exposure level monitoring, health surveillance, and 
relevant training.
    A number of European Union nations (e.g., United Kingdom, Germany, 
France, Netherlands, Norway, and Belgium) and Asian nations (Singapore 
and Korea) already utilize control banding methods comparable to COSHH 
Essential methods for management of a variety of chemical exposures in 
the workplace.
    A number of studies have been conducted to assess the validity of a 
control banding model for control of exposure to chemicals. Jones and 
Nicas (2006; Ex. #132) reviewed the COSHH Essentials model for hazard-
banding in vapor degreasing and bag-filling tasks. Their study showed 
that the model did not identify adequate controls in all scenarios with 
approximately eighteen percent of cases leaving workers potentially 
under-protected. However, in a similar study, Hashimoto et al. (2007; 
Ex. #133) showed that hazard-banding tended to overestimate the level 
of control and therefore was more protective. In 2011, Lee et al. (Ex. 
#134) found that for a paint manufacturing facility using mixtures of 
chemicals with different volatilities, exposure to the chemicals with 
higher volatility had a higher likelihood to exceed the predicted 
hazard-band. Lee also recommended further research for more precise 
task identification to better enable implementation of task-specific 
control measures.
    NIOSH provides a thorough review and critical analysis of the 
concepts, protective nature, and potential barriers to implementation 
of control banding programs (NIOSH, 2009; Ex. #135). NIOSH concluded 
that control banding can be used effectively for performing workplace 
risk assessments and implementing control solutions for many, but not 
all occupational hazards. Additionally, NIOSH found that while in some 
situations in which control banding cannot provide the precision and 
accuracy necessary to protect worker health, and in some cases control 
banding will provide a higher level of control than is necessary.
    COSHH Essentials and other control banding concepts developed in 
Europe were based initially on the European Union's pre-GHS 
classification and labeling system. Since the European Union has 
adopted the GHS in its classification and labeling rules, these risk 
phrases will no longer be available. Control banding approaches are now 
based on the hazard statements in the GHS. OSHA's adoption of the GHS 
to modify the HCS opens up the opportunity to use a control banding 
approach to chemical exposures in American workplaces based on the 
hazard classification system. This would be an alternative to focusing 
on PELs that could achieve the goal of risk management for many 
chemicals and operations in workplaces.
    OSHA is interested in exploring how it might employ these non-OEL 
approaches in a regulatory framework to address hazardous substances 
where the available hazard information does not yet provide a 
sufficient basis for the Agency's traditional approach of using risk 
assessment to establish a PEL. OSHA believes that a hazard banding 
approach could allow the Agency to establish specification requirements 
for the control of chemical exposures more efficiently, offering 
additional flexibility to employers, while maintaining the safety and 
health of the workforce. Although health hazard banding and control 
banding show some promise as vehicles for providing guidance to 
occupational health professionals for controlling exposures to workers, 
their use in a regulatory scheme presents challenges. For example, the 
agency would need to consider how, if it were to require such 
approaches, the OSH Act's requirement that standards that reduce 
significant risk to the extent feasible might be satisfied.
    OSHA is also interested in exploring the development of voluntary 
guidelines for incorporation of control banding into safety and health 
management programs in U.S. workplaces. These efforts might include the 
development and dissemination of compliance assistance materials 
(publications, safety and health topic Web pages, computer software and 
smartphone apps, e-Tools) as well as consultation services to assist 
small businesses.
    Question V.B.8: How could OSHA use the information generated under 
HazCom 2012 to pursue means of managing and controlling chemical 
exposures in an approach other than substance-by-substance regulation?
    Question V.B.9: How could such an approach satisfy legal 
requirements to reduce significant risk of material impairment and for 
technological and economic feasibility?
    Question V.B.10.: Please describe your experience in using health 
hazard and/or control banding to address exposures to chemicals in the 
workplace.
    Question V.B.11.: Are additional studies available that have 
examined the effectiveness of health hazard and control banding 
strategies in protecting workers?
    Question V.B.12.: How can OSHA most effectively use the concepts of 
health hazard and control banding in developing health standards?
    V.B.13.: How might OSHA use voluntary guidance approaches to assist 
businesses (particularly small businesses) with implementing the 
principles of hazard banding in their chemical safety plans? Could the 
GHS chemical classifications be the starting point for a useful 
voluntary hazard banding scheme? What types of information, tools, or 
other resources could OSHA provide that would be most effective to 
assist businesses, unions, and other safety and health stakeholders 
with operationalizing hazard banding principles in the workplace?
    Question V.B.14.: Should OSHA consider greater use of specification 
standards or guidance as an approach to developing health standards? If 
so, for what kinds of operations are specification approaches best 
suited?
6. Task-based Exposure Assessment and Control Approaches
    Job hazard analysis is a safety and health management tool in which 
certain jobs, tasks, processes or procedures are evaluated for 
potential hazards or risks, and controls are implemented to protect 
workers from injury and illness. Likewise, task-based assessment and 
control is a system that categorizes the task or job activity in terms 
of exposure potential and requirements for specific actions to control 
the exposure are implemented, regardless of occupational exposure 
limits. Tasks are isolated from the deconstruction of a larger process 
that is in turn part of an overall operation or project in an 
industrial setting. As industrial engineering explores the optimization 
of complex processes or systems through an evaluation of the integrated 
system of people, equipment, materials, and other components, the task-
based system attempts to evaluate work activities to define uniform 
exposure scenarios and their variables and establish targeted control 
strategies.

[[Page 61418]]

    Task-based exposure potential can be defined using readily 
available data including process operating procedures, task observation 
and analysis, job activity description, chemical inventory and toxicity 
information (hazard communication), historical exposure data, existing 
exposure databases, employee surveys, and current exposure data. Based 
on this exposure assessment, the task is matched with specific 
requirements for exposure control. Control specifications can draw on a 
broad inventory of exposure controls and administrative tools to reduce 
and prevent worker exposure to the identified hazardous substances.
    OSHA is interested in exploring task-based control approaches as a 
technique for developing specification standards for the control of 
hazardous substances in the workplace as an alternative or supplement 
to PELs. Such an approach may offer the advantage of providing 
employers with specific guidance on how to protect workers from 
exposure and reduce or eliminate the need for conducting regular 
exposure assessments to evaluate the effectiveness of exposure control 
strategies. OSHA has developed specification-oriented health standards 
in the past, in particular, those for lead and asbestos in 
construction.
    More recently, OSHA developed a control-specification-based 
approach for controlling exposures to crystalline silica dust in 
construction operations (OSHA, 2009; Ex. #136, OSHA, 2013b; Ex. #137). 
Construction operations are particularly amenable to specification 
standards due to the task-based nature of the work. The National 
Institute for Occupational Safety and Health (NIOSH), the Center to 
Protect Workers' Rights--a research arm of the Building and 
Construction Trades Department, AFL-CIO--has developed and used a 
``Task-Based Exposure Assessment Model (T-BEAM)'' for construction. The 
characteristic elements of T-BEAM are: (1) an emphasis on the 
identification, implementation, and evaluation of engineering and work 
practice controls; and (2) use of experienced, specially trained 
construction workers (construction safety and health specialists) in 
the exposure assessment process. A task-based approach was used because 
tasks, or specialized skills, form the single greatest thread of 
continuity in the dynamic environment of construction (Susi et al., 
2000; Ex. #138).
    A new American National Standards Institute Standard (ANSI A10.49) 
based on GHS health hazard categories and utilizing a task-based 
approach is also being developed to address chemical hazards in 
construction (ASSE, 2012; Ex. #139). The standard requires employers to 
first identify tasks involving the use of chemicals and create a hazard 
communication inventory for these tasks. Then the employer must 
determine the hazard level and exposure level, and finally develop a 
control plan based on the hazard and exposure classifications. If the 
chemicals used in the task are low hazard and the task is low exposure, 
then the control plan requires following the SDS and label precautions. 
If, however, the task involves greater than minimal hazard or exposure, 
a more protective control plan must be developed.
    However, developing specification standards governing exposure to 
health standards for general industry operations presents a different 
challenge. Given the diversity in the nature of industrial operations 
across a range of industry sectors that might be affected by a chemical 
standard, OSHA is concerned that it will be more difficult to develop 
specification standards for exposure controls that are specific enough 
to clearly delineate obligations of employers to protect employees, and 
yet are general enough to provide employers flexibility to implement 
controls that are suitable for their workplaces and that allow for 
future innovation in control technologies.
    Question V.B.15: OSHA requests comment on whether and how task-
based exposure control approaches might be effectively used as a 
regulatory strategy for health standards.

VI. Authority and Signature

    David Michaels, Ph.D., MPH, Assistant Secretary of Labor for 
Occupational Safety and Health, U.S. Department of Labor, 200 
Constitution Avenue NW., Washington, DC 20210, directed the preparation 
of this notice. OSHA is issuing this notice under 29 U.S.C. 653, 655, 
657; 33 U.S.C. 941; 40 U.S.C. 3704 et seq.; Secretary of Labor's Order 
1-2012 (77 FR 3912, 1/25/2012); and 29 CFR Part 1911.

    Signed at Washington, DC, on September 30, 2014.
David Michaels,
Assistant Secretary of Labor for Occupational Safety and Health.

Appendix A: History, Legal Background, and Significant Court Decisions

I. Background

    Since the OSH Act was enacted in 1970, OSHA has made significant 
achievements toward improving the health and safety of America's 
workers. The OSH Act gave ``every working man and woman in the 
Nation'' for the first time, a legal right to ``safe and healthful 
working conditions.'' OSH Act Sec.  2(a); 29 U.S.C. 651. (Ex. #9) 
Congress recognized that ``the problem of assuring safe and 
healthful workplaces for our men and women ranks in importance with 
any that engages the national attention today.'' S. Rep. 91-1282 at 
2 (1970; Ex. #17). Indeed, when establishing the OSH Act, Congress 
was concerned about protecting workers from known hazards as well as 
from the numerous new hazards entering the workplace:

    Occupational diseases which first commanded attention at the 
beginning of the industrial revolution are still undermining the 
health of workers. . . . Workers in dusty trades still contract 
various respiratory diseases. Other materials long in industrial use 
are only now being discovered to have toxic effects. In addition, 
technological advances and new processes in American industry have 
brought numerous new hazards to the workplace. S. Rep. 91-1282 at 2.

    Many of the occupational diseases first discovered during the 
industrial revolution, and which later spurred Congress to create 
OSHA, still pose a significant harm to U.S. workers. While the 
number of hazardous chemicals to which workers are exposed has 
increased exponentially due to new formulations of chemical 
mixtures, OSHA has not been successful in establishing standards 
that adequately protect workers from hazardous chemical exposures, 
even from the older, more familiar chemicals.
    OSHA's PELs are mandatory limits for air contaminants above 
which workers must not be exposed. OSHA PELs generally refer to 
differing amounts of time during which the worker can be exposed: 
(1) Time weighted averages (TWAs) which establish average limits for 
eight-hour exposures; (2) short-term limits (STELs) which establish 
limits for short term exposures; and (3) ceiling limits, which set 
never-to-be exceeded maximum exposure levels.
    OSHA's PELs have existed nearly as long as the agency itself. 
Most of OSHA's current PELs were adopted by the agency in 1971. OSHA 
currently has PELs for approximately 470 hazardous substances, which 
are included in the Z-Tables in general industry at 29 CFR part 
1910.1000 (Ex. #4) and in three maritime subsectors: Part 1915.1000 
(Shipyard Employment; Ex. #5); part 1917 (Marine Terminals; Ex. 
#140); and part 1918 (Longshoring; Ex. #141). Z-Tables that apply in 
construction are found at part 1926.55 (Ex. #6). There are 
inconsistencies in the PELs that apply across industry sectors which 
resulted from the regulatory history of each divergent industry 
sector.
    As discussed in further detail below, the Agency attempted to 
update the general industry PELs in 1989, but that revision was 
vacated by judicial decision in 1992. As such, the 1971 PELs remain 
the exposure limits with which most U.S. workplaces are required to 
comply. The Agency also promulgates ``comprehensive'' substance-
specific standards (e.g., lead, methylene chloride) which, in 
addition to PELs, require additional ancillary provisions such as 
housekeeping, exposure monitoring, and medical surveillance.

[[Page 61419]]

II. OSHA's Statutory Authority, Adoption of the PELs in 1971, and the 
1989 Attempted Revision

A. The Purpose of the OSH Act and OSHA's Authority To Regulate 
Hazardous Chemicals

    The OSH Act vests the Secretary of Labor with the power to 
``promulgate, modify, or revoke'' mandatory occupational safety and 
health standards. OSH Act section 6(b), 29 U.S.C. 655(b). An 
``occupational safety and health standard,'' as defined by section 
3(8) of the OSH Act, is a ``standard which requires conditions, or 
the adoption or use of one or more practices, means, methods, 
operations, or processes, reasonably necessary or appropriate to 
provide safe or healthful employment and places of employment.'' OSH 
Act section 3(8), 29 U.S.C. 652(8). (Ex. #9)
    The OSH Act provides three separate approaches for promulgating 
standards. The first approach, in section 6(a) of the OSH Act, 
provided OSHA with an initial two-year window in which to adopt 
standards without hearing or public comment. Additionally, sections 
6(b) and 6(c) provide methods currently available to the agency for 
promulgating health standards. Section 6(b) allows OSHA to create 
and update standards through notice and comment rulemaking, and 
section 6(c) provides OSHA with the authority to set emergency 
temporary standards. OSHA has not successfully adopted an emergency 
temporary standard for over thirty years, and it is not discussed 
further here.

B. The Adoption of the PELs Under Section 6(a)

    Under section 6(a), OSHA was permitted to adopt ``any national 
consensus standard and any established Federal standard'' so long as 
the standard ``improved safety or health for specifically designated 
employees.'' 29 U.S.C. 655(a). The purpose of providing OSHA with 
this two-year window ``was to establish as rapidly as possible 
national occupational safety and health standards with which 
industry is familiar.'' S. Rep. 91-1282 at 6. When establishing this 
fast track to rulemaking, Congress emphasized the temporary nature 
of the approach, noting that these ``standards may not be as 
effective or up to date as is desirable, but they will be useful for 
immediately providing a nationwide minimum level of health and 
safety.'' S. Rep. 91-1282 at 6. (Ex. #17)
    Establishing PELs was one of the first actions taken by OSHA. 
Most of the PELs contained in the Tables Z-1, Z-2, and Z-3 of 29 CFR 
1910.1000 (Ex. #4) for general industry, as well as those in 
construction and maritime were adopted during the initial two-year 
window under section 6(a). OSHA adopted approximately 400 
occupational exposure limits for general industry that were based on 
the American Conference of Governmental Industrial Hygienist's 
(ACGIH) 1968 list of Threshold Value Limits (TLVs). In addition, 
about 25 additional exposure limits recommended by the American 
Standards Association (presently called the American National 
Standards Institute) (ANSI), were adopted as national consensus 
standards. 36 FR 10466 (Ex. #142). Currently the exposure limits 
that apply to construction were derived from the 1970 ACGIH TLVs and 
certain substance specific Sec. 6(b) standards.
    The industry sector that is referred to today as ``Maritime'' 
has a long and somewhat confusing history. The Department of Labor 
has had some authority since 1958 for the maritime industry under 
the Longshore and Harbor Workers Compensation Act (33 U.S.C. 901 et 
seq.). Specifically authority was granted under Public Law 89-742 
for the Secretary of Labor to issue regulations to protect the 
health and safety of longshoremen, marine terminal workers, ship 
repairers, shipbuilders, and ship breakers. Under Section 4(b)(2) of 
the OSH Act, 33 U.S.C. 941 (Ex. #143) became OSHA standards in 1971.
    At that time, the Shipyard standards were in three parts of 29 
CFR; part 1915 for ship repairing, part 1916 for shipbuilding and 
part 1917 for shipbreaking. In 1982 parts 1915, 1916 and 1917 were 
consolidated into a new part 1915, Shipyards. As a consequence of 
their history, the PELs applicable to the new part 1915, Shipyards, 
are complex. Depending upon the specific operation, either the 1970 
TLVs or 1971 PELS (originally 1968 TLVs) apply. See Sec. Sec.  
1915.11, 1915.12, 1915.32 and 1915.33 (Ex. #144). Additionally, 
several of the OSHA single-substance standards apply.
    Pursuant to the Longshoremen and Harbor Worker Compensation Acts 
of 1958 amendments, in 1960 OSHA issued regulations protecting 
longshore employees, along with marine terminal employees. These 
regulations were adopted as OSHA standards and later recodified. In 
1983, OSHA issued a final standard specifically covering marine 
terminals (29 CFR part 1917) separately from longshoring. The Marine 
Terminal Standard basically requires that no employee be exposed to 
air contaminants over the limits set in the 1971 Z-Tables. See 
Sec. Sec.  1917.2, 1917.22, 23, 25. (Ex. #140)
    Longshoring operations continue to be regulated by 29 CFR Part 
1918 (Ex. #141). OSHA has consistently interpreted that the air 
contaminant exposure limits set forth in 1910.1000 (Ex. #4) are 
applicable pursuant to 1910.5(c) to longshoring because no 
quantitative exposure limits are set forth for air contaminants, 
other than carbon monoxide.
    As discussed above, the Agency was given authority to adopt 
standards to provide initial protections for workers from what the 
Congress deemed to be the most dangerous workplace threats. Congress 
felt that it was ``essential that such standards be constantly 
improved and replaced as new knowledge and techniques are 
developed.'' S. Rep. 91-1282 at 6. (Ex. #17) However, because OSHA 
has been unable to update the PELs, they remain frozen at the levels 
at which they were initially adopted. OSHA's PELs are largely based 
on acute health effects and do not take into consideration newer 
research regarding chronic effects occurring at lower occupational 
exposures. Thus, although there have been radical changes in our 
understanding of airborne contaminants, updates in technology, and 
changes to industry practices, OSHA's PELs are still based on 
research performed during the 1950s and 1960s. In contrast, the 
ACGIH annually reviews chemical substances and updates its list of 
TLVs[supreg]. Where OSHA currently has PELs for approximately 470 
chemical hazards, the ACGIH recommends TLVs[supreg] for more than 
700 chemical substances and physical agents, approximately 200 of 
which have been updated since 1971. (FACOSH, 2012; Ex. #145).

C. Section 6(b) Notice and Comment Rulemaking

    Section 6(b) of the OSH Act provides OSHA with the authority to 
promulgate health standards. OSHA promulgates two main types of 
health standards: (i) PELs, and (ii) comprehensive standards, which, 
as the name implies, consist of provisions to protect workers in 
addition to PELs. Section 6(b)(5) imposes specific requirements 
governing the adoption of health standards:

    [T]he Secretary, in promulgating standards dealing with toxic 
materials or harmful physical agents under this subsection, shall 
set the standard which most adequately assures, to the extent 
feasible, on the basis of the best available evidence, that no 
employee will suffer material impairment of health or functional 
capacity even if such employee has regular exposure to the hazard 
dealt with by such standard for the period of his working life. 
Development of standards under this subsection shall be based upon 
research, demonstrations, experiments, and such other information as 
may be appropriate. In addition to the attainment of the highest 
degree of health and safety protection for the employee, other 
considerations shall be the latest available scientific data in the 
field, the feasibility of the standards, and experience gained under 
this and other health and safety laws. Whenever practicable, the 
standard promulgated shall be expressed in terms of objective 
criteria and of the performance desired.

    29 U.S.C. 655(6)(b)(5). (Ex. #9)
    The courts have elaborated on the findings OSHA must make before 
adopting a 6(b)(5) standard. One such case, Industrial Union Dept., 
AFL-CIO v. American Petroleum Institute, 448 U.S. 607 (1980) (the 
Benzene case; Ex. #10), has had a major impact on OSHA rulemaking by 
establishing a threshold requirement that before the agency can 
promulgate a health standard it must show that a significant risk of 
material impairment exists, which can be eliminated or lessened by a 
change in practices. Additionally, the phrase ``to the extent 
feasible'' in section 6(b)(5) has been interpreted by the courts to 
require that OSHA show that a standard is both economically and 
technologically feasible. American Textile v. Donovan, 452 U.S. 490 
(1981) (the Cotton Dust case; Ex. #15); United Steelworkers v. 
Marshall, 647 F.2d 1189, 1264 (D.C. Cir. 1980) (the Lead I case; Ex. 
#12). These cases will be discussed in greater detail in Section III 
of this Appendix.

D. 1989 Air Contaminants Standard

    In 1989, OSHA published the Air Contaminants final rule, which 
remains the Agency's most significant attempt at

[[Page 61420]]

updating the PELs. Unlike typical substance-specific rulemakings, 
where OSHA develops a comprehensive standard, the Air Contaminants 
final rule was only intended to update existing PELs and to add new 
PELs for substances not currently regulated. As such, the final rule 
did not include ancillary provisions (e.g. exposure monitoring, 
medical surveillance, requirements for personal protective 
equipment, or labeling) because OSHA determined that these 
provisions would delay and unnecessarily complicate the PELs update. 
Appendix B. to this Request for Information contains the table of 
PELs from the 1989 Air Contaminants Final Rule. The table includes 
both PELs originally adopted by OSHA in 1971 and the PELs 
established under the 1989 final rule.
    In order to determine a starting point for updating the general 
industry PELs for chemicals on Tables Z-1, Z-2, and Z-3 of 29 CFR 
1910.1000 (Ex. #4), and for creating new PELs for some substances 
not listed in those tables, OSHA analyzed existing databases and 
lists of occupational exposure limits (OELs) to determine the scope 
of the rulemaking. After extensive review of all available sources 
of OELs, including the National Institute for Occupational Safety 
and Health (NIOSH) Recommended Exposure Levels (RELs), the American 
Conference of Industrial Hygienists (ACGIH) Threshold Limit Values 
(TLVs[supreg]), the American Industrial Hygiene Association (AIHA) 
Workplace Environmental Exposure Levels (WEELs), and limits from 
other countries, OSHA ultimately selected the ACGIH's 1987-88 TLVs 
to identify the basis for which substances and corresponding 
exposure values that would be included in the proposed rule. 53 FR 
20977. The TLVs were selected as a reference point because of the 
number of substances they covered, the availability of written 
documentation on how the TLVs were selected, and the general 
acceptance of the TLVs by industrial hygienists, other occupational 
health professionals, and industry. (53 FR 20967; Ex. #18, 54 FR 
2375; Ex. #7)
    After determining the scope of hazardous chemicals to be 
included in the rulemaking, OSHA began the process of identifying 
the most appropriate new PELs to be proposed. OSHA considered both 
the ACGIH TLVs and the NIOSH RELs as a starting point. (53 FR 20966-
67; Ex. #18) When the TLV and REL were similar, OSHA reviewed both 
the ACGIH documentation and the NIOSH recommendation. Where the TLV 
and REL ``differed significantly,'' OSHA reviewed the studies and 
reasoning upon which the NIOSH and ACGIH recommendations were based 
to determine which was more appropriate. OSHA presumed that a 
significant difference did not exist between the TLV and the REL for 
a chemical when:
    (a) The TLV and REL values are the same;
    (b) TLV and REL values differ by less than 10 percent;
    (c) The TLV and REL Time Weighted Averages (TWA) are the same, 
but there are differences in the Short Term Exposure Limit (STEL) or 
Ceiling (C); or
    (d) The TWA in one data base is the same, or one-half, the STEL/
C in the other data base. 53 FR 20977.
    In reviewing the evidence, OSHA first determined whether the 
studies and analyses were valid and of reasonable scientific 
quality. Second, it determined, based on the studies, if the 
published documentation of the REL or TLV would meet OSHA's legal 
requirements for setting a PEL. Thus, OSHA reviewed the evidence of 
significant risk at the existing PEL or, if there was no PEL, at 
exposures which might exist in the workplace in the absence of any 
limit. Third, OSHA reviewed the studies to determine if the new PEL 
would lead to substantial reduction in significant risk. 54 FR 2372.
    OSHA's determination of where the new PEL should be set was 
based on its review and analysis of the information found in these 
sources. OSHA set the new PELs based on a review of the available 
evidence. 54 FR 2402. Safety factors were applied on a case-by-case 
basis. (54 FR 2365, 2399; Ex. #7). Based on the analysis discussed 
above, OSHA summarized the health evidence for each individual 
substance and determined when and at what level a new limit was 
necessary to substantially reduce a significant risk of material 
impairment of health or functional capacity among American workers. 
The following example illustrates the type of analysis that OSHA 
conducted for each substance:

    OSHA had no former limit for potassium hydroxide. A ceiling 
limit of 2 mg/m(3) was proposed by the Agency based on the ACGIH 
recommendation, and NIOSH (Ex. 8-47, Table N1) concurred with this 
proposal. OSHA has concluded that this limit is necessary to afford 
workers protection from irritant effects and is establishing the 2-
mg/m(3) ceiling limit for potassium hydroxide in the final rule.

    [One commenter] (Ex. 3-830) commented that there was no basis 
for establishing an occupational limit for potassium hydroxide. OSHA 
disagrees and notes that the irritant effects of potassium hydroxide 
dusts, mists, and aerosols have been documented (ACGIH 1986/Ex. 1-3, 
p. 495; Karpov 1971/Ex. 1-1115). Although dose-response data are 
lacking for this substance, it is reasonable to expect potassium 
hydroxide to exhibit irritant properties similar to those of sodium 
hydroxide, a structurally related strong alkali. In its criteria 
document, NIOSH (1976k/Ex. 1-965) cites a personal communication 
(Lewis 1974), which reported that short-term exposures (2 to 15 
minutes) to 2 mg/m(3) sodium hydroxide caused ``noticeable'' but not 
excessive upper respiratory tract irritation. Therefore, OSHA finds 
that the 2-mg/m(3) ceiling limit will provide workers with an 
environment that minimizes respiratory tract irritation, which the 
Agency considers to be material impairment of health. To reduce 
these risks, OSHA is establishing a ceiling limit of 2 mg/m(3) for 
potassium hydroxide. (54 FR 2332 et seq.)

    OSHA proposed making 212 PELs more protective and setting new 
PELs for 164 substances not previously regulated by OSHA. Substances 
for which the PEL was already aligned with a newer TLV were not 
included.
    In order to determine whether the Air Contaminants rule was 
feasible, OSHA prepared the regulatory impact analysis in two 
phases. The first phase of its feasibility analyses involved using 
secondary databases to collect information on the chemicals to be 
regulated and the industries in which they were used. These 
databases provided information on the toxicity and health effects of 
exposure to chemicals covered by the rulemaking, on engineering 
controls, and on emergency response procedures. (54 FR 2725; Ex. 
#7).
    Two primary databases were used to collect information on the 
nature and extent of employee exposures to the substances covered by 
the rule. One database was the 1982 NIOSH National Occupational 
Exposure Survey (NOES), which collected information from 4,500 
businesses on the number of workers exposed to hazardous substances. 
The second database was OSHA's Integrated Management Information 
System (IMIS) which contains air samples taken since 1979 by OSHA 
industrial hygienists during compliance inspections. OSHA also 
consulted industrial hygienists and engineers who provided 
information about the exposure controls in use, the number and size 
of plants that would be impacted by the rulemaking, and the 
estimated costs associated with meeting the new PELs. (54 FR 2373, 
2725, 2736; Ex. #7).
    As part of the second phase of its feasibility analyses, OSHA 
performed an industry survey and site visits. The survey was the 
largest survey ever conducted by OSHA and included responses from 
5,700 firms in industries believed to use chemicals included in the 
scope of the Air Contaminants proposal. It was designed to focus on 
industry sectors that potentially had the highest compliance costs, 
identified through an analysis of existing exposure data at the 
four-digit SIC (Standards Industrial Classification) code level. 54 
FR 2843. The survey gathered data on chemicals, processes, exposures 
and controls currently in use, which ``permitted OSHA to refine the 
Phase I preliminary estimates of technical and economic feasibility. 
Site visits to 90 firms were conducted to verify the data collected 
on chemicals, processes, controls, and employee exposures.'' 54 FR 
2725; see also 54 FR 2736-39, 2768, 2843-69.
    OSHA analyzed the data collected in phases I and II to determine 
whether the updated PELs were both technologically and economically 
feasible for each industry sector covered. 54 FR 2374.
    For technological feasibility, OSHA evaluated engineering 
controls and work practices available within industry sectors to 
reduce employee exposures to the new PELs. In general, it found 
three types of controls might be employed to reduce exposures: 
Engineering controls, work practice and administrative controls, and 
personal protective equipment. Engineering controls included local 
exhaust ventilation, general ventilation, isolation of the worker 
and enclosure of the source of the emission, and product 
substitution. Work practice controls included housekeeping, material 
handling procedures, leak detection, training, and personal hygiene. 
Personal protective equipment included respirators, and where the 
chemicals involved presented skin

[[Page 61421]]

hazards, protective gloves and clothing. 54 FR 2789-90, 2840.
    OSHA found that many processes required to reduce exposure were 
``relatively standardized throughout industry and are used [to 
control exposures] for a variety of substances.'' 54 FR 2373-74. It 
``examined typical work processes found in a cross section of 
industries'' and had industry experts identify the major processes 
that had the potential for hazardous exposures above the new PELs, 
requiring new controls. For each affected industry group, OSHA 
reviewed the data it had collected to ``identify examples of 
successful application of controls to these processes.'' 54 FR 2790. 
Based on its review OSHA found that ``engineering controls and 
improved work practices [were] available to reduce exposure levels 
in almost all circumstances.'' 54 FR 2727. In some cases, it found 
respirators or other protective equipment was necessary. 54 FR 2727, 
2813-15, 2840. For each relevant industry sector (which was at the 
2, 3, or 4 digit SIC code level, depending on the processes 
involved). As the court explained in Air Contaminants, 965 F.2d at 
981 (Ex. #8):

    The SIC codes classify by type of activity for purposes of 
promoting uniformity and comparability in the presentation of data. 
As the codes go from two and three digits to four digits, the 
groupings become progressively more specific. For example, SIC Code 
28 represents ``Chemicals and Allied Products,'' SIC Code 281 
represents ``Industrial Inorganic Chemicals,'' and SIC Code 2812 
includes only ``Alkalies and Chlorine.''

    OSHA prepared a list of the processes identified and the 
engineering controls and personal protective equipment (PPE) 
required to reach the new PELs. 54 FR 2814-39. In almost all cases, 
the OSHA list showed that the new PELs could be reached through a 
combination of ventilation and enclosure controls. 54 FR 2816-39. 
OSHA received and addressed numerous comments on the controls it 
proposed for use in various industries. 54 FR 2790-2813. OSHA found 
that ``in the overwhelming majority of situations where air 
contaminants [were] encountered by workers, compliance [could] be 
achieved by applying known engineering control methods, and work 
practice improvements.'' 54 FR 2789.
    To assess economic feasibility, OSHA ``made estimates of the 
costs to reduce exposure based on the scale of operations, type of 
process, and degree of exposure reduction needed'' based primarily 
on the results of the survey. 54 FR 2373, 2841-51. For each survey 
respondent, OSHA identified the processes employed at the plant and 
made a determination about whether workers would be exposed to a 
chemical in excess of a new PEL. 54 FR 2843-47. For those processes 
where the new PEL would be exceeded, OSHA estimated the cost of 
controls necessary to meet the PEL. 54 FR 2947-51. Process control 
costs were then summed by establishment and costs ``for the survey 
establishment were then weighted (by SIC and size) to represent 
compliance costs for the universe of affected plants.'' 54 FR 2851. 
OSHA received and addressed many comments on its cost approach and 
assumptions. (54 FR 2854-62; Ex. #7).
    Based on the survey, OSHA determined that 74 percent of 
establishments with hazardous chemicals had no exposures in excess 
of the new PELs and would incur no costs, 22 percent would incur 
costs to implement additional engineering controls, and 4 percent 
would be required to provide personal protective equipment only for 
maintenance workers. 54 FR 2851. OSHA estimated the total compliance 
cost to be $788 million per year annualized over ten years at a ten 
percent discount rate. 54 FR 2851. OSHA assessed the economic impact 
of the standard on industry profits on the two-digit SIC level. 
Assuming industry would not be able to pass the additional costs on 
to customers, the average change in profits was less than one 
percent, with the largest change in SIC 30 (Rubber and Plastics) of 
2.3 percent. 54 FR 2885, 2887. Alternatively, assuming that industry 
could pass on all costs associated with the rule to its customers, 
OSHA determined that for no industry sector would prices increase on 
average more than half of a percent. 54 FR 2886, 2887. In neither 
case was the economic impact significant, OSHA found, and the new 
standard was therefore considered by the Agency to be economically 
feasible. (54 FR 2733, 2887; Ex. #7)
    The Air Contaminants final rule was published on January 19, 
1989. In the final rule, OSHA summarized the health evidence for 
each individual substance, discussed over 2,000 studies, reviewed 
and addressed all major comments submitted to the record, and 
provided a rationale for each new PEL chosen. The final rule 
differed from the proposal in a number of ways as OSHA changed many 
of its preliminary assessments presented in the proposal based on 
comments submitted to the record.
    Ultimately, the final rule adopted more protective PELs for 212 
previously regulated substances, set new PELs for 164 previously 
unregulated substances, and left unchanged an additional 52 
substances, for which lower PELs were initially proposed. OSHA 
estimated over 21 million employees were potentially exposed to 
hazardous substances in the workplace and over 4.5 million employees 
were currently exposed to levels above the old PELs or in the 
absence of a PEL. OSHA projected the final rule would result in 
potential reduction of over 55,000 lost workdays due to illnesses 
per year and annual compliance with this final rule would prevent an 
average of 683 fatalities annually from exposures to hazardous 
substances. 54 FR 2725.
    The update to the Air Contaminants standard generally received 
wide support from both industry and labor. However, there was 
dissatisfaction on the part of some industry representatives and 
union leaders, who brought petitions for review challenging the 
standard. For example, some industry petitioners argued that OSHA's 
use of generic findings, the inclusion of so many substances in one 
rulemaking, and the allegedly insufficient time provided for comment 
by interested parties created a record inadequate to support the new 
set of PELs. In contrast, the unions challenged the generic approach 
used by OSHA to promulgate the standard and argued that several PELs 
were not protective enough. The unions also asserted that OSHA's 
failure to include any ancillary provisions, such as exposure 
monitoring and medical surveillance, prevented employers from 
ensuring the exposure limits were not exceeded and resulted in less-
protective PELs.
    Fifteen of the twenty-five lawsuits were settled; of the 
remaining suits, nine were from industry groups challenging seven 
specific exposure limits, and one was from the unions challenging 16 
substances. Pursuant to 28 U.S.C. 2112(a), all petitions for review 
were consolidated for disposition and transferred to the Eleventh 
Circuit Court of Appeals. AFL-CIO v. OSHA, 965, F.2d 962, 981-82 
(11th Cir. 1992) (Air Contaminants). Although only 23 of the new 
PELs were challenged, the court ultimately decided to vacate the 
entire rulemaking, finding that ``OSHA [had] not sufficiently 
explained or supported its threshold determination that exposure to 
these substances at previous levels posed a significant risk of 
these material health impairments or that the new standard 
eliminates or reduces that risk to the extent feasible.'' Air 
Contaminants, 965 F.2d at 986-987; Ex. #8.
    After publishing the Air Contaminants Final Rule for general 
industry, OSHA proposed amending the PELs for the maritime and 
construction industry sectors and establishing PELs to cover the 
agriculture industry sector. OSHA published a Notice of Proposed 
Rulemaking (NPRM) on June 12, 1992, which included more protective 
exposure limits for approximately 210 substances currently regulated 
in the construction and maritime industries and added new exposure 
limits for approximately 160 chemicals to protect these workers. (57 
FR 26002; Ex. #146). The notice also proposed approximately 220 PELs 
to cover the agriculture industry. OSHA extended the comment period 
indefinitely while it considered possible responses to the Air 
Contaminants court decision. Once it became clear that an appeal 
would not be pursued, the Agency halted work on the project.

III. Significant Court Decisions Shaping OSHA's Rulemaking Process and 
OSHA's Approach to Updating Its Permissible Exposure Limits

    OSHA's Air Contaminants final rule is the agency's most 
significant attempt to move away from developing individual, 
substance-specific standards. As discussed above in Section II, this 
rule attempted to establish or revise 376 exposure limits for 
chemicals in a single rulemaking. OSHA's efforts in reducing 
occupational illnesses and the mortality associated with hazardous 
chemical exposure has largely been through developing substance 
specific standards, such as Hexavalent Chromium general industry (29 
CFR 1910.1026; Ex. #26), shipyards (29 CFR 1915.1026), and 
construction (29 CFR 1926.1026) and Methylene Chloride (29 CFR 
1910.1052; Ex. #27). These standards, in addition to setting PELs, 
establish other provisions to help reduce risk to workers, such as 
requirements to monitor exposure, train workers and conduct medical 
surveillance, if appropriate.

[[Page 61422]]

However, due to the associated time and costs, promulgating 
comprehensive rules for individual chemical hazards is an 
ineffective approach to address all chemical hazard exposures 
because of the sheer number of chemicals and mixtures to which 
workers are exposed on a daily basis. To date, only 30 comprehensive 
individual standards have been successfully published by the Agency 
to address hazardous chemicals in the workplace.
    The courts have had a significant impact on OSHA's rulemaking 
process by articulating specific burdens OSHA must meet before 
promulgating a standard. It was because the Air Contaminants court 
found that OSHA had failed to meet some of these burdens that the 
court vacated OSHA's attempt to update the PELs. This section 
discusses the important cases laying out OSHA's burdens under the 
OSH Act, and summarizes the reasons the Air Contaminants court gave 
for finding that OSHA had not satisfied those burdens. These cases 
influence what steps OSHA may take in the future to update the PELs.

A. The Substantial Evidence Test: OSHA's Burden of Proof for 
Promulgating Health Standards

    The test used by the courts to determine whether OSHA has 
reached its burden of proof is the ``substantial evidence test.'' 
This test, which applies to policy decisions as well as factual 
determinations, is set forth in section 6(f) of the OSH Act, which 
states: ``the determinations of the Secretary shall be conclusive if 
supported by substantial evidence in the record considered as a 
whole.'' 29 U.S.C. 655(f). ``Substantial evidence'' has been defined 
as ``such relevant evidence as a reasonable mind might accept as 
adequate to support a conclusion.'' Cotton Dust, 452 U.S. at 522; 
Ex. #15 (quoting Universal Camera Corp. v. NLRB, 340 U.S. 474, 477 
(1951) Ex. #16).
    Although the substantial evidence test requires OSHA to show 
that the record as a whole supports the final rule, OSHA is not 
required to wait for ``scientific certainty'' before promulgating a 
health standard. Benzene, 448 U.S. at 656 (Ex. #10). Rather, to meet 
its burden of proof under the ``substantial evidence test,'' the 
agency need only ``identify relevant factual evidence, to explain 
the logic and the policies underlying any legislative choice, to 
state candidly any assumptions on which it relies, and to present 
its reasons for rejecting significant contrary evidence and 
argument.'' Lead I, 647 F.2d. at 1207; Ex. #12.

B. The Air Contaminants Case

    OSHA published the Air Contaminants final rule on January 19, 
1989. As discussed in Section II, the standard adopted more 
protective PELs for 212 previously regulated substances, set new 
PELs for 164 previously unregulated substances, left unchanged the 
PELs for 52 substances for which lower limits had been proposed, and 
raised the PEL for one substance. 54 FR 2332. The rule was 
challenged by both industry and labor groups, which both raised a 
series of issues regarding the validity of the final rule.
    The first issue addressed by the court was whether OSHA's 
``generic'' approach to rulemaking used to update or create new PELs 
for 376 chemicals in a single rulemaking was permissible under the 
OSH Act. Although the Eleventh Circuit determined that the Air 
Contaminants final rule did not fit within the classic definition of 
a generic rulemaking, the court upheld the format used by OSHA to 
update the PELs. Air Contaminants, 965 F.2d at 972. The court, in so 
holding, reasoned ``nothing in the OSH Act prevented OSHA from 
addressing multiple substances in a single rulemaking.'' Air 
Contaminants, 965 F.2d at 972. The court also upheld OSHA's 
statutory authority to select the substances and determine the 
parameters of its rules. However, the court stated that even though 
OSHA was permitted to promulgate multi-substance rules, each 
substance was required to ``stand independently, i.e., . . . each 
PEL must be supported by substantial evidence in the record 
considered as a whole and accompanied by adequate explanation.'' Air 
Contaminants, 965 F.2d at 972; Ex. #8.

C. Significant Risk of a Material Impairment

1. The Benzene Case and Significant Risk

    The significant risk requirement was first articulated in 1980 
in a plurality decision of the Supreme Court in Benzene, 448 U.S. 
607. The petitioners in Benzene challenged OSHA's rule lowering its 
PEL for benzene from 10 ppm to 1 ppm. In support of the new PEL, 
OSHA found that benzene caused leukemia and that the evidence did 
not show that there was a safe threshold exposure level below which 
no excess leukemia would occur. Applying its policy to treat 
carcinogens as posing a risk at any level of exposure where such a 
threshold could not be established, OSHA chose the new PEL of 1 ppm 
based on its finding that it was the lowest feasible exposure level. 
This was because Section 6(b)(5) of the OSH Act requires standards 
to be set at the most protective level that is feasible. See 
Benzene, 448 U.S. at 633-37; Ex. #10.
    The Benzene Court rejected OSHA's approach. First, it found that 
the OSH Act did not require employers to ``eliminate all risks of 
harm from their workplaces.'' The OSH Act defines ``occupational 
safety and health standard'' to be standard that require the 
adoption of practices which are ``reasonably necessary or 
appropriate to provide safe or healthful employment and places of 
employment''. OSH Act Sec.  3(8), 29 U.S.C. 652(8); Ex. #9.
    Relying on this definition, the Court found that the Act only 
required that employers ensure that their workplaces are safe, that 
is, that their workers are not exposed to ``significant risk[s] of 
harm.'' 448 U.S. at 642. Second, the Court made clear that it is 
OSHA's burden to establish that a significant risk is present at the 
current standard before lowering a PEL. The burden of proof is 
normally on the proponent, the Court noted, and there was no 
indication in the OSH Act that Congress intended to change this 
rule. 448 U.S. at 653, 655. Thus, the Court held that, before 
promulgating a health standard, OSHA is required to make a 
``threshold finding that a place of employment is unsafe-in the 
sense that significant risks are present and can be eliminated or 
lessened by a change in practices'' before it can adopt a new 
standard. Benzene, 448 U.S. at 642; Ex. #10.
    Although the Court declined to establish a set test for 
determining whether a workplace is unsafe, it did provide guidance 
on what constitutes a significant risk. The Court stated a 
significant risk was one that a reasonable person would consider 
significant and ``take appropriate steps to decrease or eliminate.'' 
Benzene, 448 U.S. at 655 (Ex. #10). For example, it said, a one in a 
1,000 risk would satisfy the requirement. However, this example was 
merely an illustration, not a hard line rule. The Court made it 
clear that determining whether a risk was ``significant'' was not a 
``mathematical straitjacket'' and did not require the Agency to 
calculate the exact probability of harm. 448 U.S. at 655. OSHA was 
not required to support a significant risk finding ``with anything 
approaching scientific certainty'' and was free to use 
``conservative assumptions'' in interpreting the evidence. 448 U.S. 
at 656. Still, because OSHA had not made a significant risk finding 
at the 10 ppm level (indeed, the Court characterized the evidence of 
leukemia in the record at the 10 ppm level as ``sketch[y]''), the 
Court vacated the new PEL and remanded the matter to OSHA.

2. OSHA's Post-Benzene Approach to Significant Risk and Air 
Contaminants

    In past rulemakings involving hazardous chemicals, OSHA 
satisfied its requirement to show that a significant risk of harm is 
present by estimating the risk to workers subject to a lifetime of 
exposure at various possible exposure levels. These estimates have 
typically been based on quantitative risk assessments. As a general 
policy, OSHA has considered a lifetime excess risk of one death or 
serious illness per 1000 workers associated with occupational 
exposure over a 45 year working life as clearly representing a 
significant risk. However, as noted above, Benzene does not require 
OSHA to use such a rigid or formulaic criterion. Nevertheless, OSHA 
has taken a conservative approach and has used the 1:1,000 example 
as a useful benchmark for determining significant risk. This 
approach has often involved the use of the quantitative risk 
assessment models OSHA has employed in developing substance-specific 
health standards.
    In the Air Contaminants rule, OSHA departed from this approach. 
Rather, as noted above, it looked at whether studies showed excess 
effects of concern at concentrations lower than allowed under OSHA's 
existing standard. Where they did, OSHA made a significant risk 
finding and either set a PEL (where none existed previously) or 
lowered the existing PEL. These new PELs were based on agency 
judgment, taking into account the existing studies, and as 
appropriate, safety factors. Both industry and union petitioners 
challenged aspects of OSHA's approach to making its significant risk 
determinations. The AFL-CIO argued that OSHA's rule was 
``systematically under protective,'' and asserted that 16 of the 
exposure limits in the final rule were too high. For example, the 
AFL-CIO argued that OSHA had made a policy determination not to 
lower the PELs for carbon tetrachloride and vinyl bromide even 
though the exposure limits chosen

[[Page 61423]]

would continue to pose a residual risk in excess of 3.7 deaths per 
1,000 workers exposed over the course of their working lifetime. The 
court agreed with the AFL-CIO, finding that OSHA failed to provide 
adequate evidence to support the higher PEL chosen by the agency. 
The court found that some of the PELs chosen by the Agency were at 
levels that would continue to pose a significant risk of material 
health impairment, and concluded that OSHA's decision was due to 
time and resource constraints, rather than legitimate 
considerations, such as feasibility. Air Contaminants, 965 F.2d at 
976-77; Ex. #8.
    Conversely, the American Iron and Steel Institute (AISI; Ex. 
#147) argued that OSHA set the PELs for certain substances below the 
level substantiated by the evidence. AISI argued that OSHA failed to 
quantify the risk of material health impairment at present exposure 
levels posed by individual substances and instead relied on 
assumptions in order to select its updated PELs. The court agreed 
with the AISI, finding that although OSHA summarized the studies on 
health effects in the final rule, it did not explain why the 
``studies mandated a particular PEL chosen.'' Air Contaminants, 965 
F.2d at 976. Specifically, the court stated that OSHA failed to 
quantify the risk from individual substances and merely provided 
conclusory statements that the new PEL would reduce a significant 
risk of material health effects. Air Contaminants, 965 F.2d at 975.
    OSHA argued to the court that it relied on safety factors in 
setting PELs. Safety or uncertainty factors are used to ensure that 
exposure limits for a hazardous substance are set sufficiently below 
the levels at which adverse effects have been observed to assure 
adequate protection for all exposed employees. As explained in the 
1989 Air Contaminants rule, regulators use safety factors in this 
context to account for statistical limitations in studies showing no 
observed effects, the uncertainties in extrapolating effects 
observed in animals to humans, and variation in human responses. The 
size of the proper safety factor is a matter of professional 
judgment. 54 FR 2397-98
    The Eleventh Circuit rejected OSHA's use of safety factors in 
the Air Contaminants rule, however. While noting that the Benzene 
case held that OSHA is permitted ``to use conservative assumptions 
in interpreting data . . ., risking error on the side of 
overprotection rather than under protection,'' Benzene, 448 U.S. at 
656, the Air Contaminants court found that OSHA had not adequately 
supported the use of safety factors in this rule. The court observed 
that ``the difference between the level shown by the evidence and 
the final PEL is sometimes substantial,'' and assumed that though 
``it is not expressly stated, that for each of those substances OSHA 
applied a safety factor to arrive at the final standard.'' 965 F.2d 
at 978. OSHA had not indicated ``how the existing evidence for 
individual substances was inadequate to show the extent of risk for 
these factors,'' and ``failed to explain the method by which its 
safety factors were determined.'' Air Contaminants, 965 F.2d at 978. 
``OSHA may use assumptions but only to the extent that those 
assumptions have some basis in reputable scientific evidence,'' the 
court concluded. Air Contaminants, 965 F.2d at 978-979. See Section 
IV. A. for additional discussion of the use of safety factors in 
risk assessment.
    Ultimately, although the Eleventh Circuit noted that OSHA 
``probably established that most or all of the substances involved 
do pose a significant risk at some level,'' the court determined 
that OSHA failed to adequately explain or provide evidence to 
support its conclusion that ``exposure to these substances at 
previous levels posed a significant risk . . . or that the new 
standard eliminates or reduces that risk to the extent feasible.'' 
Air Contaminants, 965 F.2d at 987. Therefore, the court vacated the 
rule and remanded it to the agency.

3. Material Impairment

    Under section 6(b)(5), OSHA must set standards to protect 
employees against ``material impairment of health or functional 
capacity.'' This requirement was uncontroversial in Benzene, since 
the effect on which OSHA regulated was leukemia. However, in Air 
Contaminants, AISI argued that not all of the health effects 
addressed by OSHA in the final rule were material health effects. 
Specifically, AISI stated that the category of ``sensory 
irritation,'' which OSHA used as an endpoint to set PELs for 79 
substances, failed to distinguish between ``materially impairing 
sensory irritation and the less serious sort.'' AISI brief at page 
24. The court rejected AISI's argument. It accepted OSHA's 
explanation that material impairments may be any health effect, 
permanent or transitory, that seriously threatens the health or job 
performance of an employee, and held that, ``OSHA is not required to 
state with scientific certainty or precision the exact point at 
which each type of sensory or physical irritation becomes a material 
impairment.'' Air Contaminants, 965 F.2d at 975. ``Section 6(b)(5) 
of the [OSH] Act charges OSHA with addressing all forms of `material 
impairment of health or functional capacity,'' and not exclusively 
those causing `death or serious physical harm' or `grave danger' 
from exposure to toxic substances, the court held. Air Contaminants, 
965 F.2d at 975; Ex. #8.

D. Technological and Economic Feasibility

    Once OSHA makes its threshold finding that a significant risk is 
present at the current PEL or in the absence of a PEL and can be 
reduced or eliminated by a standard, the Agency considers 
feasibility. First, the feasibility requirement that originated in 
Section 6(b)(5) of the OSH Act requires that the standard be 
``technologically feasible,'' which generally means an industry has 
to be able to develop the technology necessary to comply with the 
requirements in the standard. Lead I, 647 F.2d at 1264-65; Ex. #12.
    Second, the standard must be ``economically feasible,'' meaning 
that an industry as a whole must be able to absorb the impact of the 
costs associated with compliance with the standard. Id. at 1265. 
OSHA has historically made determinations on technological 
feasibility and economic feasibility separately.

1. Technological Feasibility

    A standard is technologically feasible if ``a typical firm will 
be able to develop and install engineering and work practice 
controls that can meet the PEL in most operations.'' Lead I, 647 
F.2d at 1272. Standards are permitted to be ``technology forcing,'' 
meaning that OSHA can require industries to ``develop new 
technology'' or ``impose a standard which only the most 
technologically advanced plants in an industry have been able to 
achieve, even if only in some of their operations some of the 
time.'' Lead I, 647 F.2d at 1264; Ex. #12.
    Technological feasibility analysis generally focuses on 
demonstrating that PELs can be achieved through engineering and work 
practice controls. However, the concept of technological feasibility 
applies to all aspects of the standard, including air monitoring, 
housekeeping, and respiratory protection requirements. Some courts 
have required OSHA to determine whether a standard is 
technologically feasible on an industry-by-industry basis, Color 
Pigments Manufacturers Assoc. v. OSHA, 16 F.3d 1157 (Ex. #13), 1162-
63 (11th Cir. 1994); Air Contaminants, 965 F.2d at 981-82 (Ex. #8), 
while another court has upheld technological feasibility findings 
based on the nature of an activity across many industries rather 
than on a pure industry basis, Public Citizen Health Research Group 
v. United States Department of Labor, 557 F.3d 165,178-79 (3d Cir. 
2009; Ex. #14).
    Regardless, OSHA must show the existence of ``technology that is 
either already in use or has been conceived and is reasonably 
capable of experimental refinement and distribution within the 
standard's deadlines,'' Lead I, 647 F.2d 1272. Where the agency 
presents ``substantial evidence that companies acting vigorously and 
in good faith can develop the technology,'' the agency is not bound 
to the technological status quo, and ``can require industry to meet 
PELs never attained anywhere.'' Lead I, 647 F.2d 1265; Ex. #12.
    OSHA usually demonstrates the technological feasibility of a PEL 
by finding establishments in which the PEL is already being met and 
identifying the controls in use, or by arguing that even if the PEL 
is not currently being met in a given operation, the PEL could be 
met with specific additional controls. OSHA is also concerned with 
determining whether the conditions under which the PEL can be met in 
specific plants are generalizable to an industry as whole. This 
approach is very resource-intensive, as it commonly requires 
gathering detailed information on exposure levels and controls for 
each affected operation and process in an industry. OSHA's 
inspection databases usually do not record this information, and 
consequently OSHA makes site visits for the specific purpose of 
determining technological feasibility. (See Section IV. of this 
Request for Information for a detailed discussion of how OSHA 
determines technological feasibility and possible alternatives to 
current methods.)
    As noted above, in the Air Contaminants rule, OSHA made its 
feasibility determination by gathering information on work processes 
that might expose workers

[[Page 61424]]

above the new PELs, and identifying controls that had been 
successfully implemented to reduce the exposure to the new limits. 
It made these findings mainly at the two-digit SIC level, but also 
at the three- and four-digit level where appropriate given the 
processes involved. The Air Contaminants court rejected this 
approach, finding that OSHA failed to make industry-specific 
findings or identify the specific technologies capable of meeting 
the proposed limit in industry-specific operations. Air 
Contaminants, 965 F.2d at 981. While OSHA had identified primary air 
contaminant control methods: engineering controls, administrative 
controls and work practices and personal protective equipment, the 
agency, ``only provided a general description of how the generic 
engineering controls might be used in the given sector.'' Air 
Contaminants, 965 F.2d at 981. Though noting that OSHA need only 
provide evidence sufficient to justify a ``general presumption of 
feasibility,'' the court held that this ``does not grant OSHA 
license to make overbroad generalities as to feasibility or to group 
large categories of industries together without some explanation of 
why findings for the group adequately represents the different 
industries in that group.'' Air Contaminants, 965 F.2d at 981-82. 
Accordingly, the court held that OSHA failed to establish the 
technological feasibility of the new PELs in its final rule. Air 
Contaminants, 965 F.2d at 982. As noted below, in a subsequent 
rulemaking the reviewing court accepted OSHA's approach of grouping 
numbers of industries.

2. Economic Feasibility

    With respect to economic feasibility, the courts have stated ``A 
standard is feasible if it does not threaten ``massive dislocation'' 
to . . . or imperil the existence of the industry.'' United 
Steelworkers v. Marshall, 647 F.2d 1189, 1265 (D.C. Cir. 1980) Lead 
I,). In order to show this, the same court suggested, OSHA should 
``construct a reasonable estimate of compliance costs and 
demonstrate a reasonable likelihood that these costs will not 
threaten the existence or competitive structure of an industry.'' 
The same court noted, ``[T]he court probably cannot expect hard and 
precise estimates of costs. Nevertheless, the agency must of course 
provide a reasonable assessment of the likely range of costs of its 
standard, and the likely effects of those costs on the industry.'' 
Lead I, 647 F.2d at 1265; Ex. #12.
    Economic feasibility does not entail a cost-benefit analysis of 
the level of protection provided by the standard. As the Supreme 
Court noted, Congress considered the costs of creating a safe and 
healthful workplace to be the cost of doing business. Cotton Dust, 
452 U.S. at 514, 520; Ex. #15. Instead, standards are economically 
feasible if the standard will not substantially alter the industry's 
competitive structure. Forging Indus. Ass'n v. Secretary of Labor, 
773 F.2d 1436, 1453 (4th Cir. 1985; Ex. #148). In order to make a 
determination of economic feasibility, OSHA should ``construct a 
reasonable estimate of compliance costs and demonstrate a reasonable 
likelihood that these costs will not threaten the existence or 
competitive structure of an industry,'' Lead I, 647 F.2d at 1272, 
noting that such analyses will not provide absolute certainty:

    [T]he court probably cannot expect hard and precise estimates of 
costs. Nevertheless, the agency must of course provide a reasonable 
assessment of the likely range of costs of its standard, and the 
likely effects of those costs on the industry . . . . And OSHA can 
revise any gloomy forecast that estimated costs will imperil an 
industry by allowing for the industry's demonstrated ability to pass 
through costs to consumers. 647 F.2d at 1266-67.

    Again, courts have required OSHA to determine whether a standard 
is economically feasible on an industry-by-industry basis. See Air 
Contaminants, 965 F.2d at 982 (Ex. #8). Both to meet requirements 
for any Regulatory Flexibility Act (5 U.S.C. 603, 604) analysis and 
to assure that standards do not threaten the competitive structure 
of an industry, OSHA also analyzes the economic impacts on different 
size classes within an industry. However, OSHA is not required to 
show that all companies within an industry will be able to bear the 
burden of compliance or ``guarantee the continued existence of 
individual employers.'' Lead I, 647 F.2d at 1265 (Ex. #12) (quoting 
Industrial Union Dep't, AFL-CIO v. Hodgson, 499 F.2d 467, 478 (D.C. 
Cir. 1974) Ex. #55)).
    As discussed above, OSHA supported its economic feasibility 
findings for the 1989 Air Contaminants rule based primarily on the 
results of a survey of over 5700 businesses, summarizing the 
projected cost of compliance at the two-digit SIC industry sector 
level. It found that compliance costs would average less than one 
percent of profits, and, alternatively, that prices would increase 
by less than one half percent. Nonetheless, the Eleventh Circuit 
held that OSHA had failed to meet its burden. The court held that 
OSHA was required to show that the rule was economically feasible on 
an industry-by industry basis, and that OSHA had not shown that its 
analyses at the two-digit SIC industry sector level were appropriate 
to meet this burden. Air Contaminants, 965 F.2d at 982. OSHA argued 
the generic nature of the rulemaking allowed the agency ``a great 
latitude in grouping industries in order to estimate `average' 
costs,'' and that ``the costs were sufficiently low per sector to 
demonstrate feasibility not only for each sector, but each sub-
sector.'' Air Contaminants, 965 F.2d at 983. However, the court 
found that ``average estimates of cost can be extremely misleading 
in assessing the impact of particular standards on individual 
industries'' and observed that ``analyzing the economic impact for 
an entire sector could conceal particular industries laboring under 
special disabilities and likely to fail as a result of 
enforcement.'' Air Contaminants, 965 F.2d at 982. The court allowed 
that OSHA could ``find and explain that certain impacts and 
standards do apply to entire sectors of an industry'' if ``coupled 
with a showing that there are no disproportionately affected 
industries within the group.'' Air Contaminants, 965 F.2d at 982 
n.28. But in this case, the court found, OSHA had not explained why 
its use of such a ``broad grouping was appropriate.'' Air 
Contaminants, 965 F.2d at 983; Ex. #8.
    Ultimately, the court held that OSHA did not sufficiently 
explain or support its threshold determination that exposures above 
the new PELs posed significant risks of material health impairment, 
or that the new PELs eliminated or reduced the risks to the extent 
feasible. Finding that ``OSHA's overall approach to this rulemaking 
is . . . flawed,'' the court vacated the entire Air Contaminant 
rulemaking, rather than just the 23 chemicals that were contested by 
union and industry representatives. Air Contaminants, 965 F.2d at 
987(Ex. #8).
    The Eleventh Circuit denied OSHA's petition for rehearing. No 
longer having a basis to enforce the 1989 PELs, OSHA directed its 
compliance officers to stop enforcing the updated limits through a 
memo, which was followed by a Federal Register Notice on June 30, 
1993, revoking the new limits. 58 FR 35338-35351; (Ex. #19).

Appendix B: 1989 PELs Table

                                                        Table Z-1-A--Limits For Air Contaminants
                                                      [From the vacated 1989 final rule--Ex. #149]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                    TWA                  STEL                 Ceiling
                 Substance                             Cas No.            ------------------------------------------------------------------     Skin
                                                                              ppm      mg/m\3\      ppm      mg/m\3\      ppm      mg/m\3\   Designation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Acetaldehyde..............................  75-07-0......................        100        180        150        270  .........  .........  ...........
Acetic acid...............................  64-19-7......................         10         25  .........  .........  .........  .........  ...........
Acetic anhydride..........................  108-24-7.....................  .........  .........  .........  .........          5         20  ...........
Acetone...................................  67-64-1......................        750       1800       1000      24006  .........  .........  ...........
Acetonitrile..............................  75-05-8......................         40         70         60        105  .........  .........  ...........
2-Acetylamino-fluorine; see 1910.1014.....  53-96-3......................
Acetylene dichloride; see 1,2-              540-59-0.....................
 Dichloroethylene.
Acetylene tetrabromide....................  79-27-6......................          1         14  .........  .........  .........  .........  ...........
Acetylsalicylic acid (Aspirin)............  50-78-2......................  .........          5  .........  .........  .........  .........  ...........
Acrolein..................................  107-02-8.....................        0.1       0.25        0.3        0.8  .........  .........  ...........
Acrylamide................................  79-06-1......................  .........       0.03  .........  .........  .........  .........           X

[[Page 61425]]

 
Acrylic acid..............................  79-10-7......................         10         30  .........  .........  .........  .........           X
Acrylonitrile; see 1910.1045..............  107-13-1.....................  .........  .........  .........  .........  .........  .........  ...........
Aldrin....................................  309-00-2.....................  .........       0.25  .........  .........  .........  .........           X
Allyl alcohol.............................  107-18-6.....................          2          5          4         10  .........  .........           X
Allyl chloride............................  107-05-1.....................          1          3          2          6  .........  .........  ...........
Allyl glycidyl ether (AGE)................  106-92-3.....................          5         22         10         44  .........  .........  ...........
Allyl propyl disulfide....................  2179-59-1....................          2         12          3         18  .........  .........  ...........
alpha-Alumina.............................  1344-28-1....................  .........  .........  .........  .........  .........  .........  ...........
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Aluminum (as Al) Metal....................  7429-90-5.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
                                            Pyro powders.................  .........          5  .........  .........  .........  .........  ...........
                                            Welding fumes................  .........          5  .........  .........  .........  .........  ...........
                                            Soluble salts................  .........          2  .........  .........  .........  .........  ...........
                                            Alkyls.......................  .........          2  .........  .........  .........  .........  ...........
4-Aminodiphenyl; see 1910.1011............  92-67-1.
2-Aminoethanol; see Ethanolamine..........  141-43-5.
2-Aminopyridine...........................  504-29-0.....................        0.5          2  .........  .........  .........  .........  ...........
Amitrole..................................  61-82-5......................  .........        0.2  .........  .........  .........  .........  ...........
Ammonia...................................  7664-41-7....................  .........  .........         35         27  .........  .........  ...........
Ammonium chloride fume....................  12125-02-9...................  .........         10  .........         20  .........  .........  ...........
Ammonium sulfamate........................  7773-06-0.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
n-Amyl acetate............................  628-63-7.....................        100        525  .........  .........  .........  .........  ...........
Sec-Amyl acetate..........................  626-38-0.....................        125        650  .........  .........  .........  .........  ...........
Aniline and homologs......................  62-53-3......................          2          8  .........  .........  .........  .........           X
Anisidine (o-, p-isomers).................  29191-52-4...................  .........        0.5  .........  .........  .........  .........  ...........
Antimony and compounds (as Sb)............  7440-36-0....................  .........        0.5  .........  .........  .........  .........  ...........
ANTU (alpha naphthyl-thiourea)............  86-88-4......................  .........        0.3  .........  .........  .........  .........  ...........
Arsenic, organic compounds (as As)........  7440-38-2....................  .........        0.5  .........  .........  .........  .........  ...........
Arsenic, inorganic compounds (as As); see   Varies with compound.........  .........  .........  .........  .........  .........  .........  ...........
 1910.1018.
Arsine....................................  7784-42-1....................       0.05        0.2  .........  .........  .........  .........  ...........
Asbestos; see 1910.1001...................  Varies.......................  .........  .........  .........  .........  .........  .........  ...........
Atrazine..................................  1912-24-9....................  .........          5  .........  .........  .........  .........  ...........
Azinphos-methyl...........................  86-50-0......................  .........        0.2  .........  .........  .........  .........           X
Barium, soluble compounds.................  7440-39-3....................  .........        0.5  .........  .........  .........  .........  ...........
Barium sulfate............................  7727-43-7.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Benomyl...................................  17804-35-2.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Benzene; see 1910.1028. See Table Z-2 for   71-43-2.
 the limits applicable in the operations
 or sectors excluded in 1910.1028.
Benzidine; see 1910.1010..................  92-87-5.
p-Benzoquinone; see Quinone...............  106-51-4.
Benzo(a)pyrene; see Coal tar pitch
 volatiles
Benzoyl peroxide..........................  94-36-0......................  .........          5  .........  .........  .........  .........  ...........
Benzyl chloride...........................  100-44-7.....................          1          5  .........  .........  .........  .........  ...........
Beryllium and beryllium compounds (as Be).  7440-41-7....................      0.002  .........    \1\.005  .........      0.025  .........  ...........
Biphenyl; see Diphenyl....................  92-52-4.
Bismuth telluride, undoped................  1304-82-1.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Bismuth telluride, Se-doped...............  1304-82-1....................  .........          5  .........  .........  .........  .........  ...........
Borates, tetra, sodium salts:
    Anhydrous.............................  1330-43-4....................  .........  .........         10  .........  .........  .........  ...........
    Decahydrate...........................  1303-96-4....................  .........  .........         10  .........  .........  .........  ...........
    Penta-hydrate.........................  12179-04-3...................  .........  .........         10  .........  .........  .........  ...........
Boron oxide...............................  1303-86-2.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable Fraction..........  .........          5  .........  .........  .........  .........  ...........
Boron tribromide..........................  10294-33-4...................  .........  .........  .........  .........          1         10  ...........
Boron trifluoride.........................  7637-07-2....................  .........  .........  .........  .........          1          3  ...........
Bromacil..................................  314-40-9.....................          1         10  .........  .........  .........  .........  ...........
Bromine...................................  7726-95-6....................        0.1        0.7        0.3          2  .........  .........  ...........
Bromine pentafluoride.....................  7789-30-2....................        0.1        0.7  .........  .........  .........  .........  ...........
Bromoform.................................  75-25-2......................        0.5          5  .........  .........  .........  .........           X
Butadiene (1,3- Butadiene); see 1910.1051.  106-99-0.
Butane....................................  106-97-8.....................        800       1900  .........  .........  .........  .........  ...........
Butanethiol; see Butyl mercaptan..........  109-79-5.
2-Butanone (Methyl ethyl ketone)..........  78-93-3......................        200        590        300        885  .........  .........  ...........

[[Page 61426]]

 
2-Butoxyethanol...........................  111-76-2.....................         25        120  .........  .........  .........  .........           X
n-Butyl-acetate...........................  123-86-4.....................        150        710        200        950  .........  .........  ...........
sec-Butyl acetate.........................  105-46-4.....................        200        950  .........  .........  .........  .........  ...........
tert-Butyl acetate........................  540-88-5.....................        200        950  .........  .........  .........  .........  ...........
Butyl acrylate............................  141-32-2.....................         10         55  .........  .........  .........  .........  ...........
n-Butyl alcohol...........................  71-36-3......................  .........  .........  .........  .........         50        150           X
sec-Butyl alcohol.........................  78-92-2......................        100        305  .........  .........  .........  .........  ...........
tert-Butyl alcohol........................  75-65-0......................        100        300        150        450  .........  .........  ...........
Butylamine................................  109-73-9.....................  .........  .........  .........  .........          5         15           X
tert-Butyl Chromate (as CrO3).............  1189-85-1....................  .........  .........  .........  .........  .........        0.1           X
n-Butyl glycidyl ether (BGE)..............  2426-08-6....................         25        135  .........  .........  .........  .........  ...........
n-Butyl lactate...........................  138-22-7.....................          5         25  .........  .........  .........  .........  ...........
Butyl mercaptan...........................  109-79-5.....................        0.5        1.5  .........  .........  .........  .........  ...........
o-sec-Butylphenol.........................  89-72-5......................          5         30  .........  .........  .........  .........           X
p-tert-Butyltoluene.......................  98-51-1......................         10         60         20        120  .........  .........  ...........
Cadmium (all forms, as Cd); see 1910.1027   7440-43-9.
 See Table Z-2 for the limits applicable
 in the operations or sectors excluded in
 1910.1027.
Calcium carbonate.........................  1317-65-3.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Calcium cyanamide.........................  156-62-7.....................  .........        0.5  .........  .........  .........  .........  ...........
Calcium hydroxide; see particulates not     1305-62-0....................  .........          5  .........  .........  .........  .........  ...........
 otherwise regulated.
Calcium oxide.............................  1305-78-8....................  .........          5  .........  .........  .........  .........  ...........
Calcium silicate..........................  1344-95-2....................  .........  .........  .........  .........  .........  .........  ...........
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Calcium sulfate...........................  7778-18-9.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Camphor, synthetic........................  76-22-2.
Camphor, synthetic........................  76-22-2......................  .........          2  .........  .........  .........  .........  ...........
Caprolactam...............................  105-60-2.
                                            Dust.........................  .........          1  .........          3  .........  .........  ...........
                                            Vapor........................          5         20         10         40  .........  .........  ...........
Captafol (Difolatan[supreg])..............  2425-06-1....................  .........        0.1  .........  .........  .........  .........  ...........
Captan....................................  133-06-2.....................  .........          5  .........  .........  .........  .........  ...........
Carbaryl (Sevin[supreg])..................  63-25-2......................  .........          5  .........  .........  .........  .........  ...........
Carbofuran (Furadan[supreg])..............  1563-66-2....................  .........        0.1  .........  .........  .........  .........  ...........
Carbon black..............................  1333-86-4....................  .........        3.5  .........  .........  .........  .........  ...........
Carbon dioxide............................  124-38-9.....................     10,000     18,000     30,000     54,000  .........  .........  ...........
                                                                                                         0          0
Carbon disulfide..........................  75-15-0......................          4         12         12         36  .........  .........           X
Carbon monoxide...........................  630-08-0.....................         35         40  .........  .........        200        229  ...........
Carbon tetrabromide.......................  558-13-4.....................        0.1        1.4        0.3          4  .........  .........  ...........
Carbon tetrachloride......................  56-23-5......................          2       12.6  .........  .........  .........  .........  ...........
Carbonyl fluoride.........................  353-50-4.....................          2          5          5         15  .........  .........  ...........
Catechol (Pyrocatechol)...................  120-80-9.....................          5         20  .........  .........  .........  .........           X
Cellulose.................................  9004-34-6.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Cesium hydroxide..........................  21351-79-1...................  .........          2  .........  .........  .........  .........  ...........
Chlordane.................................  57-74-9......................  .........        0.5  .........  .........  .........  .........           X
Chlorinated camphene......................  8001-35-2....................  .........        0.5  .........          1  .........  .........           X
Chlorinated diphenyl oxide................  55720-99-5...................  .........        0.5  .........  .........  .........  .........  ...........
Chlorine..................................  7782-50-5....................        0.5        1.5          1          3  .........  .........  ...........
Chlorine dioxide..........................  10049-04-4...................        0.1        0.3        0.3        0.9  .........  .........  ...........
Chlorine trifluoride......................  7790-91-2....................  .........  .........  .........  .........        0.1        0.4  ...........
Chloro-acetaldehyde.......................  107-20-0.....................  .........  .........  .........  .........          1          3  ...........
alpha-Chloroaceto-phenone (Phenacy1         532-27-4.....................       0.05        0.3  .........  .........  .........  .........  ...........
 chloride).
Chloroacetyl chloride.....................  79-04-9......................       0.05        0.2  .........  .........  .........  .........  ...........
Chlorobenzene.............................  108-90-7.....................         75        350  .........  .........  .........  .........  ...........
o-Chloro-benzylidene malononitrile........  2698-41-1....................  .........  .........  .........  .........       0.05        0.4           X
Chloro-bromomethane.......................  74-97-5......................        200       1050  .........  .........  .........  .........  ...........
2-Chloro-1,3-butadiene; see beta-           126-99-8.....................  .........  .........  .........  .........  .........  .........  ...........
 Chloroprene.
Chloro-difluoromethane....................  75-45-6......................       1000       3500  .........  .........  .........  .........  ...........
Chlorodiphenyl (42% Chlorine) (PCB).......  53469-21-9...................  .........          1  .........  .........  .........  .........           X
Chlorodiphenyl (54% Chlorine) (PCB).......  11097-69-1...................  .........        0.5  .........  .........  .........  .........           X
1-Chloro,2,3-epoxypropane; see              106-89-8.
 Epichlorohydrin.
2-Chloroethanol; see Ethylene chlorohydrin  107-07-3.
Chloroethylene; see Vinyl chloride........  75-01-4.
Chloroform (Trichloro-methane)............  67-66-3......................          2       9.78  .........  .........  .........  .........  ...........
bis(Chloro-methyl) ether; see 1910.1008...  542-88-1.
Chloromethyl methyl ether; see 1910.1006..  107-30-2.
1-Chloro-l-nitropropane...................  600-25-9.....................          2         10  .........  .........  .........  .........  ...........
Chloropenta-fluoroethane..................  76-15-3......................       1000       6320  .........  .........  .........  .........  ...........
Chloropicrin..............................  76-06-2......................        0.1        0.7  .........  .........  .........  .........  ...........

[[Page 61427]]

 
beta-Chloroprene..........................  126-99-8.....................         10         35  .........  .........  .........  .........           X
o-Chlorostyrene...........................  2039-87-4....................         50        285         75        428  .........  .........  ...........
o-Chlorotoluene...........................  95-49-8......................         50        250  .........  .........  .........  .........  ...........
2-Chloro-6-trichloro-methyl pyridine......  1929-82-4.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Chlorpyrifos..............................  2921-88-2....................  .........        0.2  .........  .........  .........  .........           X
Chromic acid and chromates (as CrO3); see   Varies with compound.........  .........  .........  .........  .........        0.1  .........  ...........
 1910.1026. See Table Z-2 for the exposure
 limit for any operations or sectors where
 the exposure limit in 1910.1026 is stayed
 or are otherwise not in effect.
Chromium (II) compounds (as Cr)...........  Varies with compound.........  .........        0.5  .........  .........  .........  .........  ...........
Chromium (III) compounds (as Cr)..........  Varies with compound.........  .........        0.5  .........  .........  .........  .........  ...........
Chromium metal and insoluble salts........  7440-47-3....................  .........          1  .........  .........  .........  .........  ...........
Chrysene; see Coal tar pitch volatiles
Clopidol..................................  2971-90-6.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Coal dust (less than 5% Si02), quartz,      N/A..........................  .........          2  .........  .........  .........  .........  ...........
 respirable fraction.
Coal dust (greater than or equal to 5%      N/A..........................  .........        0.1  .........  .........  .........  .........  ...........
 Si02) respirable quartz fraction.
Coal tar pitch volatiles (benzene soluble   8007-45-2....................  .........        0.2  .........  .........  .........  .........  ...........
 fraction), anthracene, BaP, phenanthrene,
 acridine, chrysene, pyrene.
Cobalt metal, dust, and fume (as Co)......  7440-48-4....................  .........       0.05  .........  .........  .........  .........  ...........
Cobalt carbonyl (as Co)...................  10210-68-1...................  .........        0.1  .........  .........  .........  .........  ...........
Cobalt hydrocarbonyl (as Co)..............  16842-03-8...................  .........        0.1  .........  .........  .........  .........  ...........
Coke oven emissions; See 1910.1029
Copper....................................  7440-50-8.
                                            Fume (as Cu).................  .........        0.1  .........  .........  .........  .........  ...........
                                            Dusts and mists (as Cu)......  .........          1  .........  .........  .........  .........  ...........
Cotton dust, raw This 8-hour TWA applies
 to respirable dust as measured by a
 vertical elutriator cotton dust or
 equivalent instrument. The time-weighted
 average applies to the cotton waste
 processing operations of waster recycling
 (sorting, blending, cleaning, and
 willowing) and garnetting. See also
 1910.1043 for cotton dust limits
 applicable to other sectors.
Crag herbicide (Sesone)...................  136-78-7.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Cresol, all isomers.......................  1319-77-3; 95-48-7; 108-39-4;          5         22  .........  .........  .........  .........           X
                                             106-44-5.
Crotonaldehyde............................  123-73-9; 4170-30-3..........  .........          2          6  .........  .........  .........  ...........
Crufomate.................................  106-44-5.....................  .........          5  .........  .........  .........  .........  ...........
Cumene....................................  98-82-8......................         50        245  .........  .........  .........  .........           X
Cyanamide.................................  420-04-2.....................  .........          2  .........  .........  .........  .........  ...........
Cyanides (as CN)..........................  151-50-0.....................  .........          5  .........  .........  .........  .........  ...........
Cyanogen..................................  460-19-5.....................         10         20  .........  .........  .........  .........  ...........
Cyanogen chloride.........................  506-77-4.....................  .........  .........  .........  .........        0.3        0.6  ...........
Cyclohexane...............................  110-82-7.....................        300       1050  .........  .........  .........  .........  ...........
Cyclohexanol..............................  108-93-0.....................         50        200  .........  .........  .........  .........           X
Cyclohexanone.............................  108-94-1.....................         25        100  .........  .........  .........  .........           X
Cyclohexene...............................  110-83-8.....................        300       1015  .........  .........  .........  .........  ...........
Cyclohexylamine...........................  108-91-8.....................         10         40  .........  .........  .........  .........  ...........
Cyclonite.................................  121-82-4.....................  .........        1.5  .........  .........  .........  .........           X
Cyclopentadiene...........................  542-92-7.....................         75        200  .........  .........  .........  .........  ...........
Cyclopentane..............................  287-92-3.....................        600       1720  .........  .........  .........  .........  ...........
Cyhexatin.................................  13121-70-5...................  .........          5  .........  .........  .........  .........  ...........
2,4-D (Dichlorophenoxy-acetic acid).......  94-75-7......................  .........         10  .........  .........  .........  .........  ...........
Decaborane................................  17702-41-9...................       0.05        0.3       0.15        0.9  .........  .........           X
Demeton-(Systox[supreg])..................  8065-48-3....................  .........        0.1  .........  .........  .........  .........           X
Diborane..................................  19207-45-7...................        0.1        0.1  .........  .........  .........  .........  ...........
Dichlorodiphenyltri-chloroethane (DDT)....  50-29-3......................  .........          1  .........  .........  .........  .........           X
Dichlorvos (DDVP).........................  62-73-7......................  .........          1  .........  .........  .........  .........           X
Diacetone alcohol (4-Hydroxy-4-methyl-2-    123-42-2.....................         50        240  .........  .........  .........  .........  ...........
 pentanone).
1,2-Diaminoethane; see Ethylenediamine....  107-15-3.
Diazinon..................................  333-41-5.....................  .........        0.1  .........  .........  .........  .........           X
Diazomethane..............................  334-88-3.....................        0.2        0.4  .........  .........  .........  .........  ...........
1,2-Dibromo-3-chloropropane; see 1910.1044  96-12-8.
2-N-Dibutylamino-ethanol..................  102-81-8.....................          2         14  .........  .........  .........  .........  ...........
Dibutyl phosphate.........................  107-66-4.....................          1          5          2         10  .........  .........  ...........
Dibutyl phthalate.........................  84-74-2......................  .........          5  .........  .........  .........  .........  ...........
Dichloro-acetylene........................  7572-29-4....................  .........  .........  .........  .........        0.1        0.4  ...........

[[Page 61428]]

 
o-Dichlorobenzene.........................  95-50-1......................  .........  .........  .........  .........         50        300  ...........
p-Dichlorobenzene.........................  106-46-7.....................         75        450        110        675  .........  .........  ...........
3,3'-Dichloro-benzidine; see 1910.1007....  91-94-1.
Dichlorodifluoro-methane..................  75-71-8......................       1000       4950  .........  .........  .........  .........  ...........
1,3-Dichloro-5,5-dimethyl hydantoin.......  118-52-5.....................  .........        0.2  .........        0.4  .........  .........  ...........
1,1-Dichloroethane........................  75-34-3......................        100        400  .........  .........  .........  .........  ...........
1,2-Dichloroethylene......................  540-59-0.....................        200        790  .........  .........  .........  .........  ...........
Dichloroethyl ether.......................  111-44-4.....................          5         30         10         60  .........  .........           X
Dichloro-methane; see Methylene chloride..  75-09-2.
Dichloromono-fluoromethane................  75-43-4......................         10         40  .........  .........  .........  .........  ...........
1,1-Dichloro- 1-nitroethane...............  594-72-9.....................          2         10  .........  .........  .........  .........  ...........
1,2-Dichloropropane; see Propylene          78-87-5.
 dichloride.
1,3-Dichloropropene.......................  542-75-6.....................          1          5  .........  .........  .........  .........           X
2,2-Dichloro-propionic acid...............  75-99-0......................          1          6  .........  .........  .........  .........  ...........
Dichloro-tetrafluoroethane................  76-14-2......................       1000       7000  .........  .........  .........  .........  ...........
Dicrotophos...............................  141-66-2.....................  .........       0.25  .........  .........  .........  .........           X
Dicyclo-pentadiene........................  77-73-6......................          5         30  .........  .........  .........  .........  ...........
Dicyclo-pentadienyl iron..................  102-54-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Dieldrin..................................  60-57-1......................  .........       0.25  .........  .........  .........  .........           X
Diethanolamine............................  111-42-2.....................          3         15  .........  .........  .........  .........  ...........
Diethylamine..............................  109-89-7.....................         10         30         25         75  .........  .........  ...........
2-Diethylamino-ethanol....................  100-37-8.....................         10         50  .........  .........  .........  .........  ...........
Diethylene triamine.......................  111-40-0.....................          1          4  .........  .........  .........  .........  ...........
Diethyl ether; see Ethyl ether............  60-29-7.
Diethyl ketone............................  96-22-0......................        200        705  .........  .........  .........  .........  ...........
Diethyl phthalate.........................  84-66-2......................  .........          5  .........  .........  .........  .........  ...........
Difluorodibromo-methane...................  75-61-6......................        100        860  .........  .........  .........  .........  ...........
Diglycidyl ether (DGE)....................  2238-07-5....................        0.1        0.5  .........  .........  .........  .........  ...........
Dihydroxy-benzene; see Hydroquinone.......  123-31-9.
Diisobutyl ketone.........................  108-83-8.....................         25        150  .........  .........  .........  .........  ...........
Diisopropylamine..........................  108-18-9.....................          5         20  .........  .........  .........  .........           X
4-Dimethylamino-azobenzene; see 1910.1015.  60-11-7.
Dimethoxy-methane; see Methylal...........  109-87-5.
Dimethyl acetamide........................  127-19-5.....................         10         35  .........  .........  .........  .........           X
Dimethylamine.............................  124-40-3.....................         10         18  .........  .........  .........  .........  ...........
Dimethylamino-benzene; see Xylidine.......  1300-73-8.
Dimethylaniline (N,N-Dimethylaniline).....  121-69-7.....................          5         25         10         50  .........  .........           X
Dimethyl-benzene; see Xylene..............  Varies with isomer.
Dimethyl-1,2-dibromo-2,2-dichloroethyl      300-76-5.....................  .........          3  .........  .........  .........  .........           X
 phosphate.
Dimethyl-formamide........................  68-12-2......................         10         30  .........  .........  .........  .........           X
2,6-Dimethyl-4-heptanone; see Diisobutyl    108-83-8.
 ketone.
1,1-Dimethyl-hydrazine....................  57-14-7......................        0.5          1  .........  .........  .........  .........           X
Dimethyl-phthalate........................  131-11-3.....................  .........          5  .........  .........  .........  .........  ...........
Dimethyl sulfate..........................  77-78-1......................        0.1        0.5  .........  .........  .........  .........           X
Dinitolmide (3,5-Dinitro-o-toluamide).....  148-01-6.....................  .........          5  .........  .........  .........  .........  ...........
Dinitrobenzene (all isomers)..............  (alpha): 528-29-0............  .........          1  .........  .........  .........  .........           X
                                            (meta): 99-65-0..............
                                            (para-): 100-25-4............
Dinitro-o-cresol..........................  534-52-1.....................  .........        0.2  .........  .........  .........  .........           X
Dinitrotoluene............................  121-14-2.....................  .........        1.5  .........  .........  .........  .........           X
Dioxane (Diethylene dioxide)..............  123-91-1.....................         25         90  .........  .........  .........  .........           X
Dioxathion (Delnav).......................  78-34-2......................  .........        0.2  .........  .........  .........  .........           X
Diphenyl (Biphenyl).......................  92-52-4......................        0.2          1  .........  .........  .........  .........  ...........
Diphenylamine.............................  122-39-4.....................  .........         10  .........  .........  .........  .........  ...........
Diphenylmethane diisocyanate; see           101-68-8.
 Methylene bisphenyl isocyanate.
Dipropylene glycol methyl ether...........  34590-94-8...................        100        600        150        900  .........  .........           X
Dipropyl ketone...........................  123-19-3.....................         50        235  .........  .........  .........  .........  ...........
Diquat....................................  85-00-7......................  .........        0.5  .........  .........  .........  .........  ...........
Di-sec octyl phthalate (Di-2-ethylhexyl     117-81-7.....................  .........          5  .........         10  .........  .........  ...........
 phthalate).
Disulfiram................................  97-77-8......................  .........          2  .........  .........  .........  .........  ...........
Disulfoton................................  298-04-4.....................  .........        0.1  .........  .........  .........  .........           X
2,6-Di-tert-butyl-p-cresol................  128-37-0.....................  .........         10  .........  .........  .........  .........  ...........
Diuron....................................  330-54-1.....................  .........         10  .........  .........  .........  .........  ...........
Divinyl benzene...........................  108-576......................         10         50  .........  .........  .........  .........  ...........
Emery.....................................  112-62-9.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Endosulfan................................  115-29-7.....................  .........        0.1  .........  .........  .........  .........           X
Endrin....................................  72-20-8......................  .........        0.1  .........  .........  .........  .........           X
Epichlorohydrin...........................  106-89-8.....................          2          8  .........  .........  .........  .........           X
EPN.......................................  2104-64-5....................  .........        0.5  .........  .........  .........  .........           X
1,2-Epoxypropane; see Propylene oxide.....  75-56-9.
2,3-Epoxy-l-propanol; see Glycidol........  556-52-5.
Ethanethiol; see Ethyl mercaptan..........  75-08-1.
Ethanolamine..............................  141-43-5.....................          3          8          6         15  .........  .........  ...........

[[Page 61429]]

 
Ethion....................................  563-12-2.....................  .........        0.4  .........  .........  .........  .........           X
2-Ethoxyethanol [In Process of 6(b)         110-80-5.
 Rulemaking].
2-Ethoxyethyl acetate (Cellosolve acetate)  111-15-9.
 [In Process of 6(b) Rulemaking].
Ethyl acetate.............................  141-78-6.....................        400       1400  .........  .........  .........  .........  ...........
Ethyl acrylate............................  140-88-5.....................          5         20         25        100  .........  .........           X
Ethyl alcohol (Ethanol)...................  64-17-5......................       1000       1900  .........  .........  .........  .........  ...........
Ethylamine................................  75-04-7......................         10         18  .........  .........  .........  .........  ...........
Ethyl amyl ketone (5-Methyl-3-heptanone)..  106-68-3.....................         25        130  .........  .........  .........  .........  ...........
Ethyl benzene.............................  100-41-4.....................        100        435        125        545  .........  .........  ...........
Ethyl bromide.............................  74-96-4......................        200        890        250       1110  .........  .........  ...........
Ethyl butyl ketone (3-Heptanone)..........  106-35-4.....................         50        230  .........  .........  .........  .........  ...........
Ethyl chloride............................  75-00-3......................       1000       2600  .........  .........  .........  .........  ...........
Ethyl ether...............................  60-29-7......................        400       1200        500       1500  .........  .........  ...........
Ethyl formate.............................  109-94-4.....................        100        300  .........  .........  .........  .........  ...........
Ethyl mercaptan...........................  75-08-1......................        0.5          1  .........  .........  .........  .........  ...........
Ethyl silicate............................  78-10-4......................         10         85  .........  .........  .........  .........  ...........
Ethylene chlorohydrin.....................  107-07-3.....................  .........  .........  .........  .........          1          3           X
Ethylenediamine...........................  107-15-3.....................         10         25  .........  .........  .........  .........  ...........
Ethylene dibromide; see Table Z-2.........  106-93-4.
Ethylene dichloride.......................  107-06-2.....................          1          4          2          8  .........  .........  ...........
Ethylene glycol...........................  107-21-1.....................  .........  .........  .........  .........         50        125  ...........
Ethylene glycol dinitrate.................  628-96-6.....................  .........  .........  .........        0.1  .........  .........           X
Ethylene glycol methyl acetate; see Methyl  110-49-6.
 cellosolve acetate.
Ethyleneimine; see 1910.1012..............  151-56-4.
Ethylene oxide; see 1910.1047.............  75-21-8.
Ethylidene chloride; see 1,1-               75-34-3.
 Dichloroethane.
Ethylidene norbornene.....................  16219-75-3...................  .........  .........  .........  .........          5         25  ...........
N-Ethylmorpholine.........................  100-74-3.....................          5         23  .........  .........  .........  .........           X
Fenamiphos................................  22224-92-6...................  .........        0.1  .........  .........  .........  .........           X
Fensulfothion (Dasanit)...................  115-90-2.....................  .........        0.1  .........  .........  .........  .........  ...........
Fenthion..................................  55-38-9......................  .........        0.2  .........  .........  .........  .........           X
Ferbam....................................  14484-64-1.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Ferrovanadium dust........................  12604-58-9...................  .........          1  .........          3  .........  .........  ...........
Fluorides (as F)..........................  Varies with compound.........  .........        2.5  .........  .........  .........  .........  ...........
Fluorine..................................  7782-41-4....................        0.1        0.2  .........  .........  .........  .........  ...........
Fluoro-trichloromethane (Trichlorofluoro-   75-69-4......................  .........  .........  .........  .........       1000       5600  ...........
 methane).
Fonofos...................................  944-22-9.....................  .........        0.1  .........  .........  .........  .........           X
Formaldehyde; see 1910.1048...............  50-00-0.
Formamide.................................  75-12-7......................         20         30         30         45  .........  .........  ...........
Formic acid...............................  64-18-6......................          5          9  .........  .........  .........  .........  ...........
Furfural..................................  98-01-1......................          2          8  .........  .........  .........  .........           X
Furfuryl alcohol..........................  98-00-0......................         10         40         15         60  .........  .........           X
Gasoline..................................  8006-61-9....................        300        900        500       1500  .........  .........  ...........
Gemanium tetrahydride.....................  7782-65-2....................        0.2        0.6  .........  .........  .........  .........  ...........
Glutaraldehyde............................  111-30-8.....................  .........  .........  .........  .........        0.2        0.8  ...........
Glycerin (mist)...........................  56-81-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Glycidol..................................  556-52-5.....................         25         75  .........  .........  .........  .........  ...........
Glycol monoethyl ether; see 2-              110-80-5.
 Ethoxyethanol.
Grain dust (oat, wheat, barley)...........  N/A..........................  .........         10  .........  .........  .........  .........  ...........
Graphite, natural respirable dust.........  7782-42-5....................  .........        2.5  .........  .........  .........  .........  ...........
Graphite, synthetic.......................  N/A.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Guthion[supreg]; see Azinphos methyl......  86-50-0.
Gypsum....................................  7778-18-9.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Hafnium...................................  7440-58-6....................  .........        0.5  .........  .........  .........  .........  ...........
Heptachlor................................  76-44-8......................  .........        0.5  .........  .........  .........  .........           X
Heptane (n-Heptane).......................  142-82-5.....................        400       1600        500       2000  .........  .........  ...........
Hexachloro-butadiene......................  87-68-3......................       0.02       0.24  .........  .........  .........  .........  ...........
Hexachlorocyclo-pentadiene................  77-47-4......................       0.01        0.1  .........  .........  .........  .........  ...........
Hexa-chloroethane.........................  67-72-1......................          1         10  .........  .........  .........  .........           X
Hexachloro-naphthalene....................  1335-87-1....................  .........        0.2  .........  .........  .........  .........           X
Hexafluoro-acetone........................  684-16-2.....................        0.1        0.7  .........  .........  .........  .........           X
n-Hexane..................................  110-54-3.....................         50        180  .........  .........  .........  .........  ...........
Hexane isomers............................  Varies with compound.........        500       1800       1000       3600  .........  .........  ...........
2-Hexanone (Methyl n-butyl ketone)........  591-78-6.....................          5         20  .........  .........  .........  .........  ...........
Hexone (Methyl isobutyl ketone)...........  108-10-1.....................         50        205         75        300  .........  .........  ...........
sec-Hexyl acetate.........................  108-84-9.....................         50        300  .........  .........  .........  .........  ...........

[[Page 61430]]

 
Hexylene glycol...........................  107-41-5.....................  .........  .........  .........  .........         25        125  ...........
Hydrazine.................................  302-01-2.....................        0.1        0.1  .........  .........  .........  .........           X
Hydrogenated terphenyls...................  61788-32-7...................        0.5          5  .........  .........  .........  .........  ...........
Hydrogen bromide..........................  10035-10-6...................  .........  .........  .........  .........          3         10  ...........
Hydrogen chloride.........................  7647-01-0....................  .........  .........  .........  .........          5          7  ...........
Hydrogen cyanide..........................  74-90-8......................  .........  .........        4.7          5  .........  .........           X
Hydrogen fluoride (as F)..................  7664-39-3....................          3  .........          6  .........  .........  .........  ...........
Hydrogen peroxide.........................  7722-84-1....................          1        1.4  .........  .........  .........  .........  ...........
Hydrogen selenide (as Se).................  7783-07-5....................       0.05        0.2  .........  .........  .........  .........  ...........
Hydrogen sulfide..........................  7783-06-4....................         10         14         15         21  .........  .........  ...........
Hydroquinone..............................  123-31-9.....................  .........          2  .........  .........  .........  .........  ...........
2-Hydroxypropyl acrylate..................  999-61-1.....................        0.5          3  .........  .........  .........  .........           X
Indene....................................  95-13-6......................         10         45  .........  .........  .........  .........  ...........
Indium and compounds (as In)..............  7440-74-6....................  .........        0.1  .........  .........  .........  .........  ...........
Iodine....................................  7553-56-2....................  .........  .........  .........  .........        0.1          1  ...........
Iodoform..................................  75-47-8......................        0.6         10  .........  .........  .........  .........  ...........
Iron oxide (dust and fume as Fe) Total      1309-37-1....................  .........         10  .........  .........  .........  .........  ...........
 particulate.
Iron pentacarbonyl (as Fe)................  13463-40-6...................        0.1        0.8        0.2        1.6  .........  .........  ...........
Iron salts (soluble) (as Fe)..............  Varies with compound.........  .........          1  .........  .........  .........  .........  ...........
Isoamyl acetate...........................  123-92-2.....................        100        525  .........  .........  .........  .........  ...........
Isoamyl alcohol (primary and secondary)...  123-51-3.....................        100        360        125        450  .........  .........  ...........
Isobutyl acetate..........................  110-19-0.....................        150        700  .........  .........  .........  .........  ...........
Isobutyl alcohol..........................  78-83-1......................         50        150  .........  .........  .........  .........  ...........
Isooctyl alcohol..........................  26952-21-6...................         50        270  .........  .........  .........  .........           X
Isophorone................................  78-59-1......................          4         23  .........  .........  .........  .........  ...........
Isophorone diisocyanate...................  4098-71-9....................      0.005  .........       0.02  .........  .........  .........           X
2-Isopropoxy-ethanol......................  109-59-1.....................         25        105  .........  .........  .........  .........  ...........
Isopropyl acetate.........................  108-21-4.....................        250        950        310       1185  .........  .........  ...........
Isopropyl alcohol.........................  67-63-0......................        400        980        500       1225  .........  .........  ...........
Isopropylamine............................  75-31-0......................          5         12         10         24  .........  .........  ...........
N-Isopropylaniline........................  768-52-5.....................          2         10  .........  .........  .........  .........           X
Isopropyl ether...........................  108-20-3.....................        500       2100  .........  .........  .........  .........  ...........
Isopropyl glycidyl ether (IGE)............  4016-14-2....................         50        240         75        360  .........  .........  ...........
Kaolin....................................  N/A.                           .........  .........  .........  .........  .........  .........  ...........
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Ketene....................................  463-51-4.....................        0.5        0.9        1.5          3  .........  .........  ...........
Lead inorganic (as Pb); see 1910.1025.....  7439-92-1.
Limestone.................................  1317-65-3.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Lindane...................................  58-89-9......................  .........        0.5  .........  .........  .........  .........           X
Lithium hydride...........................  7580-67-8....................  .........      0.025  .........  .........  .........  .........  ...........
L.P.G. (Liquefied petroleum gas)..........  68476-85-7...................       1000       1800  .........  .........  .........  .........  ...........
Magnesite.................................  546-93-0.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Magnesium oxide fume, total particulate...  1309-48-4.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Malathion.................................  121-75-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........           X
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........           X
Maleic anhydride..........................  108-31-6.....................       0.25          1  .........  .........  .........  .........  ...........
Manganese compounds (as Mn)...............  7439-96-5....................  .........  .........  .........  .........  .........          5  ...........
Manganese fume (as Mn)....................  7439-96-5....................  .........          1  .........          3  .........  .........  ...........
Manganese cyclopentadienyl tricarbonyl (as  12079-65-1...................  .........        0.1  .........  .........  .........  .........           X
 Mn).
Manganese tetroxide (as Mn)...............  1317-35-7....................  .........          1  .........  .........  .........  .........  ...........
Marble....................................  1317-65-3.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Mercury (aryl and inorganic) (as Hg)......  7439-97-6....................  .........  .........  .........  .........  .........        0.1           X
Mercury (organo) alkyl compounds (as Hg)..  7439-97-6....................  .........       0.01  .........       0.03  .........  .........           X
Mercury (vapor) (as Hg)...................  7439-97-6....................  .........       0.05  .........  .........  .........  .........           X
Mesityl oxide.............................  141-79-7.....................         15         60         25        100  .........  .........  ...........
Methacrylic acid..........................  79-41-4......................         20         70  .........  .........  .........  .........           X
Methanethiol; see Methyl mercaptan........  74-93-1.
Methomyl (Lannate)........................  16752-77-5...................  .........        2.5  .........  .........  .........  .........  ...........
Methoxychlor..............................  72-43-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
2-Methoxyethanol; see Methyl cellosolve...  109-86-4.
4-Methoxyphenol...........................  150-76-5.....................  .........          5  .........  .........  .........  .........  ...........
Methyl acetate............................  79-20-9......................        200        610        250        760  .........  .........  ...........
Methyl acetylene (Propyne)................  74-99-7......................       1000       1650  .........  .........  .........  .........  ...........
Methyl acetylene-propadiene mixture (MAPP)  .............................       1000       1800       1250       2250  .........  .........  ...........
Methyl acrylate...........................  96-33-3......................         10         35  .........  .........  .........  .........           X

[[Page 61431]]

 
Methyl-acrylonitrile......................  126-98-7.....................          1          3  .........  .........  .........  .........           X
Methylal (Dimethoxy-methane)..............  109-87-5.....................       1000       3100  .........  .........  .........  .........  ...........
Methyl alcohol............................  67-56-1......................        200        260        250        325  .........  .........           X
Methylamine...............................  74-89-5......................         10         12  .........  .........  .........  .........  ...........
Methyl amyl alcohol; see Methyl isobutyl    108-11-2.
 carbinol.
Methyl n-amyl ketone......................  110-43-0.....................        100        465  .........  .........  .........  .........  ...........
Methyl bromide............................  74-83-9......................          5         20  .........  .........  .........  .........           X
Methyl butyl ketone; see 2-Hexanone.......  591-78-6.
Methyl cellosolve (2-Methoxyethanol)......  109-86-4.....................         25         80  .........  .........  .........  .........           X
Methyl cellosolve acetate (2-Methoxyethyl   110-49-6.....................         25        120  .........  .........  .........  .........           X
 acetate).
Methyl chloride...........................  74-87-3......................         50        105        100        210  .........  .........  ...........
Methyl chloroform (1,1,1-Trichloroethane).  71-55-6......................        350       1900        450       2450  .........  .........  ...........
Methyl 2-cyanoacrylate....................  137-05-3.....................          2          8          4         16  .........  .........  ...........
Methyl cyclohexane........................  108-87-2.....................        400       1600  .........  .........  .........  .........  ...........
Methyl-cyclohexanol.......................  25639-42-3...................         50        235  .........  .........  .........  .........  ...........
o-Methylcyclo-hexanone....................  583-60-8.....................         50        230         75        345  .........  .........           X
Methylcyclo-pentadienyl manganese           12108-13-3...................  .........        0.2  .........  .........  .........  .........           X
 tricarbonyl (as Mn).
Methyl demeton............................  8022-00-2....................  .........        0.5  .........  .........  .........  .........           X
4,4'-Methylene bis(2-chloroaniline)         101-14-4.....................       0.02       0.22  .........  .........  .........  .........           X
 (MBOCA).
Methylene bis(4-cyclo-hexylisocyanate)....  5124-30-1....................  .........  .........  .........  .........       0.01       0.11           X
Methylene chloride; see 1910.1052.........  75-09-2.
Methylene-dianiline; see 1910.1050........  101-77-9.
Methyl ethyl ketone peroxide (MEKP).......  1338-23-4....................  .........  .........  .........  .........        0.7          5  ...........
Methyl formate............................  107-31-3.....................        100        250        150        375  .........  .........  ...........
Methyl hydrazine (Monomethyl hydrazine)...  60-34-4......................  .........  .........  .........  .........        0.2       0.35           X
Methyl iodide.............................  74-88-4......................          2         10  .........  .........  .........  .........           X
Methyl isoamyl ketone.....................  110-12-3.....................         50        240  .........  .........  .........  .........  ...........
Methyl isobutyl carbinol..................  108-11-2.....................         25        100         40        165  .........  .........           X
Methyl isobutyl ketone; see Hexone........  108-10-1.
Methyl isocyanate.........................  624-83-9.....................       0.02       0.05  .........  .........  .........  .........           X
Methyl isopropyl ketone...................  563-80-4.....................        200        705  .........  .........  .........  .........  ...........
Methyl mercaptan..........................  74-93-1......................        0.5          1  .........  .........  .........  .........  ...........
Methyl methacrylate.......................  80-62-6......................        100        410  .........  .........  .........  .........  ...........
Methyl parathion..........................  298-00-0.....................  .........        0.2  .........  .........  .........  .........           X
Methyl propyl ketone; see 2-Pentanone.....  107-87-9.
Methyl silicate...........................  681-84-5.....................          1          6  .........  .........  .........  .........  ...........
alpha-Methyl styrene......................  98-83-9......................         50        240        100        485  .........  .........  ...........
Methylene bisphenyl isocyanate (MDI)......  101-68-8.....................  .........  .........  .........  .........       0.02        0.2  ...........
Metribuzin................................  21087-64-9...................  .........          5  .........  .........  .........  .........  ...........
Mica; see Silicates.......................  N/A.
Molybdenum (as Mo)........................  7439-98-7.
                                            Soluble compounds............  .........          5  .........  .........  .........  .........  ...........
                                            Insoluble compounds total      .........         10  .........  .........  .........  .........  ...........
                                             dust.
                                            Insoluble compounds..........  .........          5  .........  .........  .........  .........  ...........
                                            Respirable fraction..........
Monocrotophos (Azodrin)...................  6923-22-4....................  .........       0.25  .........  .........  .........  .........  ...........
Monomethyl aniline........................  100-61-8.....................        0.5          2  .........  .........  .........  .........           X
Morpholine................................  110-91-8.....................         20         70         30        105  .........  .........           X
Naphtha (Coal tar)........................  8030-30-6....................        100        400  .........  .........  .........  .........  ...........
Naphthalene...............................  91-20-3......................         10         50         15         75  .........  .........  ...........
alpha-Naphthylamine; see 1910.1004........  134-32-7.
beta-Naphthylamine; see 1910.1009.........  91-59-8.
Nickel carbonyl (as Ni)...................  13463-39-3...................      0.001      0.007  .........  .........  .........  .........  ...........
Nickel, metal and insoluble compounds (as   7440-02-0....................  .........          1  .........  .........  .........  .........  ...........
 Ni).
Nickel, soluble compounds (as Ni).........  7440-02-0....................  .........        0.1  .........  .........  .........  .........  ...........
Nicotine..................................  54-11-5......................  .........        0.5  .........  .........  .........  .........           X
Nitric acid...............................  7697-37-2....................          2          5          4         10  .........  .........  ...........
Nitric oxide..............................  10102-43-9...................         25         30  .........  .........  .........  .........  ...........
p-Nitroaniline............................  100-01-6.....................  .........          3  .........  .........  .........  .........           X
Nitrobenzene..............................  98-95-3......................          1          5  .........  .........  .........  .........           X
p-Nitrochloro-benzene.....................  100-00-5.....................  .........          1  .........  .........  .........  .........           X
4-Nitrodiphenyl; see 1910.1003............  92-93-3.
Nitroethane...............................  79-24-3......................        100        310  .........  .........  .........  .........  ...........
Nitrogen dioxide..........................  10102-44-0...................  .........  .........          1        1.8  .........  .........  ...........
Nitrogen trifluoride......................  7783-54-2....................         10         29  .........  .........  .........  .........  ...........
Nitroglycerin.............................  55-63-0......................  .........  .........  .........       0.11  .........  .........           X
Nitromethane..............................  75-52-5......................        100        250  .........  .........  .........  .........  ...........
1-Nitropropane............................  108-03-2.....................         25         90  .........  .........  .........  .........  ...........
2-Nitropropane............................  79-46-9......................         10         35  .........  .........  .........  .........  ...........
N-Nitrosodimethyl-amine; see 1910.1016....  62-75-9.
Nitrotoluene..............................  o-isomer 88-72-2.............          2         11  .........  .........  .........  .........           X
                                            m-isomer 99-08-1.............
                                            p-isomer 99-99-0.............
Nitrotrichloro-methane; see Chloropicrin..  76-06-2.

[[Page 61432]]

 
Nonane....................................  111-84-2.....................        200       1050  .........  .........  .........  .........  ...........
Octachloro-naphthalene....................  2234-13-1....................  .........        0.1  .........        0.3  .........  .........           X
Octane....................................  111-65-9.....................        300       1450        375       1800  .........  .........  ...........
Oil mist, mineral.........................  8012-95-1....................  .........          5  .........  .........  .........  .........  ...........
Osmium tetroxide (as Os)..................  20816-12-0...................     0.0002      0.002     0.0006      0.006  .........  .........  ...........
Oxalic acid...............................  144-62-7.....................  .........          1  .........          2  .........  .........  ...........
Oxygen difluoride.........................  7783-41-7....................  .........  .........  .........  .........       0.05        0.1  ...........
Ozone.....................................  10028-15-6...................        0.1        0.2        0.3        0.6  .........  .........  ...........
Paraffin wax fume.........................  8002-74-2....................  .........          2  .........  .........  .........  .........  ...........
Paraquat, respirable dust.................  4685-14-7....................  .........        0.1  .........  .........  .........  .........           X
Parathion.................................  56-38-2......................  .........        0.1  .........  .........  .........  .........           X
Particulates not otherwise regulated......  N/A.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Pentaborane...............................  19624-22-7...................      0.005       0.01      0.015       0.03  .........  .........  ...........
Pentachloro-naphthalene...................  1321-64-8....................  .........        0.5  .........  .........  .........  .........           X
Pentachloro-phenol........................  87-86-5......................  .........        0.5  .........  .........  .........  .........           X
Pentaerythritol...........................  115-77-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Pentane...................................  109-66-0.....................        600       1800        750       2250  .........  .........  ...........
2-Pentanone (Methyl propyl ketone)........  107-87-9.....................        200        700        250        875  .........  .........  ...........
Perchloro-ethylene (Tetrachloro-ethylene).  127-18-4.....................         25        170  .........  .........  .........  .........  ...........
Perchloromethyl mercaptan.................  594-42-3.....................        0.1        0.8  .........  .........  .........  .........  ...........
Perchloryl fluoride.......................  7616-94-6....................          3         14          6         28  .........  .........  ...........
Perlite.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Petroleum distillates (Naphtha)...........  8002-05-9....................        400       1600  .........  .........  .........  .........  ...........
Phenol....................................  108-95-2.....................          5         19  .........  .........  .........  .........           X
Phenothiazine.............................  92-84-2......................  .........          5  .........  .........  .........  .........           X
p-Phenylene diamine.......................  106-50-3.....................  .........        0.1  .........  .........  .........  .........           X
Phenyl ether, vapor.......................  101-84-8.....................          1          7  .........  .........  .........  .........  ...........
Phenyl ether-biphenyl mixture, vapor......  N/A..........................          1          7  .........  .........  .........  .........  ...........
Phenylethylene; see Styrene...............  100-42-5.
Phenyl glycidyl ether (PGE)...............  122-60-1.....................          1          6  .........  .........  .........  .........  ...........
Phenylhydrazine...........................  100-63-0.....................          5         20         10         45  .........  .........           X
Phenyl mercaptan..........................  108-98-5.....................        0.5          2  .........  .........  .........  .........  ...........
Phenylphosphine...........................  638-21-1.....................  .........  .........  .........  .........       0.05       0.25  ...........
Phorate...................................  298-02-2.....................  .........       0.05  .........        0.2  .........  .........           X
Phosdrin (Mevinphos[supreg])..............  7786-34-7....................       0.01        0.1       0.03        0.3  .........  .........           X
Phosgene (Carbonyl chloride)..............  75-44-5......................        0.1        0.4  .........  .........  .........  .........  ...........
Phosphine.................................  7803-51-2....................        0.3        0.4          1          1  .........  .........  ...........
Phosphoric acid...........................  7664-38-2....................  .........          1  .........          3  .........  .........  ...........
Phosphorus (yellow).......................  7723-14-0....................  .........        0.1  .........  .........  .........  .........  ...........
Phosphorus oxychloride....................  10025-87-3...................        0.1        0.6  .........  .........  .........  .........  ...........
Phosphorus pentachloride..................  10026-13-8...................  .........          1  .........  .........  .........  .........  ...........
Phosphorus pentasulfide...................  1314-80-3....................  .........          1  .........          3  .........  .........  ...........
Phosphorus trichloride....................  7719-12-2....................        0.2        1.5        0.5          3  .........  .........  ...........
Phthalic anhydride........................  85-44-9......................          1          6  .........  .........  .........  .........  ...........
m-Phthalodinitrile........................  626-17-5.....................  .........          5  .........  .........  .........  .........  ...........
Picloram..................................  1918-02-1.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Picric acid...............................  88-89-1......................  .........        0.1  .........  .........  .........  .........           X
Piperazine dihydrochloride................  142-64-3.....................  .........          5  .........  .........  .........  .........  ...........
Pindone (2-Pivalyl- 1,3-indandione).......  83-26-1......................  .........        0.1  .........  .........  .........  .........  ...........
Plaster of Paris..........................  7778-18-9.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Platinum (as Pt)..........................  7440-06-4.
                                            Metal........................  .........          1  .........  .........  .........  .........  ...........
                                            Soluble salts................  .........      0.002  .........  .........  .........  .........  ...........
Portland cement...........................  65997-15-1.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Potassium hydroxide.......................  1310-58-3....................  .........  .........  .........  .........  .........          2  ...........
Propane...................................  74-98-6......................       1000       1800  .........  .........  .........  .........  ...........
Propargyl alcohol.........................  107-19-7.....................          1          2  .........  .........  .........  .........           X
beta-Propriolactone; see 1910.1013........  57-57-8.
Propionic acid............................  79-09-4......................         10         30  .........  .........  .........  .........  ...........
Propoxur (Baygon).........................  114-26-1.....................  .........        0.5  .........  .........  .........  .........  ...........
n-Propyl acetate..........................  109-60-4.....................        200        840        250       1050  .........  .........  ...........
n-Propyl alcohol..........................  71-23-8......................        200        500        250        625  .........  .........  ...........
n-Propyl nitrate..........................  627-13-4.....................         25        105         40        170  .........  .........  ...........
Propylene dichloride......................  78-87-5......................         75        350        110        510  .........  .........  ...........
Propylene glycol dinitrate................  6423-43-4....................       0.05        0.3  .........  .........  .........  .........  ...........
Propylene glycol monomethyl ether.........  107-98-2.....................        100        360        150        540  .........  .........  ...........

[[Page 61433]]

 
Propylene imine...........................  75-55-8......................          2          5  .........  .........  .........  .........           X
Propylene oxide...........................  75-56-9......................         20         50  .........  .........  .........  .........  ...........
Propyne; see Methyl acetylene.............  74-99-7.
Pyrethrum.................................  8003-34-7....................  .........          5  .........  .........  .........  .........  ...........
Pyridine..................................  110-86-1.....................          5         15  .........  .........  .........  .........  ...........
Quinone...................................  106-51-4.....................        0.1        0.4  .........  .........  .........  .........  ...........
Resorcinol................................  108-46-3.....................         10         45         20         90  .........  .........  ...........
Rhodium (as Rh), metal fume and insoluble   7440-16-6....................  .........        0.1  .........  .........  .........  .........  ...........
 compounds.
Rhodium (as Rh), soluble compounds........  7440-16-6....................  .........      0.001  .........  .........  .........  .........  ...........
Ronnel....................................  299-84-3.....................  .........         10  .........  .........  .........  .........  ...........
Rosin core solder pyrolysis products, as    .............................  .........        0.1  .........  .........  .........  .........  ...........
 formaldehyde.
Rotenone..................................  83-79-4......................  .........          5  .........  .........  .........  .........  ...........
Rouge.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Selenium compounds (as Se)................  7782-49-2....................  .........        0.2  .........  .........  .........  .........  ...........
Selenium hexafluoride (as Se).............  7783-79-1....................       0.05        0.4  .........  .........  .........  .........  ...........
Silica, amorphous, precipitated and gel...  .............................  .........          6  .........  .........  .........  .........  ...........
Silica, amorphous, diatomaceous earth,      68855-54-9...................  .........          6  .........  .........  .........  .........  ...........
 containing less than 1% crystalline
 silica.
Silica, crystalline cristobalite            14464-46-1...................  .........       0.05  .........  .........  .........  .........  ...........
 respirable dust.
Silica, crystalline, quartz, respirable     14808-60-7...................  .........        0.1  .........  .........  .........  .........  ...........
 dust.
Silica, crystalline tripoli (as quartz),    1317-95-9....................  .........        0.1  .........  .........  .........  .........  ...........
 respirable dust.
Silica, crystalline tridymite respirable    15468-32-3...................  .........       0.05  .........  .........  .........  .........  ...........
 dust.
Silica, fused, respirable dust............  60676-86-0...................  .........        0.1  .........  .........  .........  .........  ...........
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Silicates (less than 1% crystalline silica)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mica (respirable dust)....................  12001-26-2...................  .........          3  .........  .........  .........  .........  ...........
Soapstone, total dust.....................  .............................  .........          6  .........  .........  .........  .........  ...........
Soapstone, respirable dust................  .............................  .........          3  .........  .........  .........  .........  ...........
Talc (containing asbestos): Use asbestos
 limit; see 1910.1001.
Talc (containing no asbestos), respirable   14807-96-6...................  .........          2  .........  .........  .........  .........  ...........
 dust.
Tremolite; asbestiform--see 1910.1001; non- .............................  .........  .........  .........  .........  .........  .........  ...........
 asbestiform--see 57 FR 24310, June 8,
 1992.
Silicon...................................  7440-21-3.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Silicon carbide...........................  409-21-2.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Silicon tetrahydride......................  7803-62-5....................          5          7  .........  .........  .........  .........  ...........
Silver, metal and soluble compounds (as     7440-22-4....................  .........       0.01  .........  .........  .........  .........  ...........
 Ag).
Soapstone; see Silicates
Sodium azide..............................  26628-22-8.
                                            (as HN3).....................  .........  .........  .........  .........        0.1  .........           X
                                            (as NaN3 )...................  .........  .........  .........  .........  .........        0.3           X
Sodium bisulfite..........................  7631-90-5....................  .........          5  .........  .........  .........  .........  ...........
Sodium fluoroacetate......................  62-74-8......................  .........       0.05  .........       0.15  .........  .........           X
Sodium hydroxide..........................  1310-73-2....................  .........  .........  .........  .........  .........          2  ...........
Sodium metabisulfite......................  7681-57-4....................  .........          5  .........  .........  .........  .........  ...........
Starch....................................  9005-25-8.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Stibine...................................  7803-52-3....................        0.1        0.5  .........  .........  .........  .........  ...........
Stoddard solvent..........................  8052-41-3....................        100        525  .........  .........  .........  .........  ...........
Strychnine................................  57-24-9......................  .........       0.15  .........  .........  .........  .........  ...........
Styrene...................................  100-42-5.....................         50        215        100        425  .........  .........  ...........
Subtilisins (Proteolytic enzymes).........  1395-21-7....................  .........  .........  .........  .........  .........   0. 00006  ...........
Sucrose...................................  57-50-1.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Sulfur dioxide............................  7446-09-5....................          2          5          5         13  .........  .........  ...........
Sulfur hexafluoride.......................  2551-62-4....................       1000       6000  .........  .........  .........  .........  ...........
Sulfuric acid.............................  7664-93-9....................  .........          1  .........  .........  .........  .........  ...........
Sulfur monochloride.......................  10025-67-9...................  .........  .........  .........  .........          1          6  ...........
Sulfur pentafluoride......................  5714-22-7....................  .........  .........  .........  .........       0.01        0.1  ...........
Sulfur tetrafluoride......................  7783-60-0....................  .........  .........  .........  .........        0.1        0.4  ...........
Sulfuryl fluoride.........................  2699-79-8....................          5         20         10         40  .........  .........  ...........
Sulprofos.................................  35400-43-2...................  .........          1  .........  .........  .........  .........  ...........
Systox[supreg]; see Demeton...............  8065-48-3.
2,4,5-T...................................  93-76-5......................  .........         10  .........  .........  .........  .........  ...........
Talc; see Silicates.
Tantalum, metal and oxide dust............  7440-25-7....................  .........          5  .........  .........  .........  .........  ...........
TEDP (Sulfotep)...........................  3689-24-5....................  .........        0.2  .........  .........  .........  .........           X
Tellurium and compounds (as Te)...........  13494-80-9...................  .........        0.1  .........  .........  .........  .........  ...........
Tellurium hexafluoride (as Te)............  7783-80-4....................       0.02        0.2  .........  .........  .........  .........  ...........

[[Page 61434]]

 
Temephos..................................  3383-96-8.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
TEPP......................................  107-49-3.....................  .........       0.05  .........  .........  .........  .........           X
Terphenyls................................  26140-60-3...................  .........  .........  .........  .........        0.5          5  ...........
1,1,1,2-Tetrachloro-2,2-difluoroethane....  76-11-9......................        500       4170  .........  .........  .........  .........  ...........
1,1,2,2-Tetrachloro 1,2-difluoroethane....  76-12-0......................        500       4170  .........  .........  .........  .........  ...........
1,1,2,2-Tetrachloro-ethane................  79-34-5......................          1          7  .........  .........  .........  .........           X
Tetrachoro-ethylene; see Perchloro-         127-18-4.
 ethylene.
Tetrachloro-methane; see Carbon             56-23-5.
 tetrachloride.
Tetrachloro-naphthalene...................  1335-88-2....................  .........          2  .........  .........  .........  .........           X
Tetraethyl lead (as Pb)...................  78-00-2......................  .........      0.075  .........  .........  .........  .........           X
Tetrahydrofuran...........................  109-99-9.....................        200        590        250        735  .........  .........  ...........
Tetramethyl lead (as Pb)..................  75-74-1......................  .........      0.075  .........  .........  .........  .........           X
Tetramethyl succinonitrile................  3333-52-6....................        0.5          3  .........  .........  .........  .........           X
Tetranitro-methane........................  509-14-8.....................          1          8  .........  .........  .........  .........  ...........
Tetrasodium pyrophosphate.................  7722-88-5....................  .........          5  .........  .........  .........  .........  ...........
Tetryl (2,4,6-Trinitro-phenyl-methyl-       479-45-8.....................  .........        0.1  .........  .........  .........  .........           X
 nitramine).
Thallium, soluble compounds (as Tl).......  7440-28-0....................  .........        0.1  .........  .........  .........  .........           X
4,4'-Thiobis (6-tert-Butyl-m-cresol)......  96-69-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Thioglycolic acid.........................  68-11-1......................          1          4  .........  .........  .........  .........           X
Thionyl chloride..........................  7719-09-7....................  .........  .........  .........  .........          1          5  ...........
Thiram....................................  137-26-8.....................  .........          5  .........  .........  .........  .........  ...........
Tin, inorganic compounds (except oxides)    7440-31-5....................  .........          2  .........  .........  .........  .........  ...........
 (as Sn).
Tin, organic compounds (as Sn)............  7440-31-5....................  .........        0.1  .........  .........  .........  .........           X
Tin oxide (as Sn).........................  7440-31-5....................  .........          2  .........  .........  .........  .........  ...........
Titanium dioxide..........................  13463-67-7.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Toluene...................................  108-88-3.....................        100        375        150        560  .........  .........  ...........
Toluene-2,4-diisocyanate (TDI)............  584-84-9.....................      0.005       0.04       0.02       0.15  .........  .........  ...........
m-Toluidine...............................  108-44-1.....................          2          9  .........  .........  .........  .........           X
o-Toluidine...............................  95-53-4......................          5         22  .........  .........  .........  .........           X
p-Toluidine...............................  106-49-0.....................          2          9  .........  .........  .........  .........           X
Toxaphene; see Chlorinated camphene.......  8001-35-2.
Tremolite; see Silicates..................  N/A.
Tributyl phosphate........................  126-73-8.....................        0.2        2.5  .........  .........  .........  .........  ...........
Trichloroacetic acid......................  76-03-9......................          1          7  .........  .........  .........  .........  ...........
1,2,4-Trichloro-benzene...................  120-82-1.....................  .........  .........  .........  .........          5         40  ...........
1,1,1-Trichloroethane; see Methyl           71-55-6.
 chloroform.
1,1,2-Trichloroethane.....................  79-00-5......................         10         45  .........  .........  .........  .........           X
Trichloro-ethylene........................  79-01-6......................         50        270        200       1080  .........  .........  ...........
Trichloro-methane; see Chloroform.........  67-66-3.
Trichloro-naphthalene.....................  1321-65-9....................  .........          5  .........  .........  .........  .........           X
1,2,3-Trichloropropane....................  96-18-4......................         10         60  .........  .........  .........  .........  ...........
1,1,2-Trichloro-1,2,2-trifluoroethane.....  76-13-1......................       1000       7600       1250       9500  .........  .........  ...........
Triethylamine.............................  121-44-8.....................         10         40         15         60  .........  .........  ...........
Trifluorobromo-methane....................  75-63-8......................       1000       6100  .........  .........  .........  .........  ...........
Trimellitic anhydride.....................  552-30-7.....................      0.005       0.04  .........  .........  .........  .........  ...........
Trimethylamine............................  75-50-3......................         10         24         15         36  .........  .........  ...........
Trimethyl benzene.........................  25551-13-7...................         25        125  .........  .........  .........  .........  ...........
Trimethyl phosphite.......................  121-45-9.....................          2         10  .........  .........  .........  .........  ...........
2,4,6-Trinitrophenyl; see Picric acid.....  88-89-1.
2,4,6-Trinitrophenylmethyl nitramine; see   479-45-8.
 Tetryl.
2,4,6-Trinitrotoluene (TNT)...............  118-96-1.....................  .........        0.5  .........  .........  .........  .........           X
Triorthocresyl phosphate..................  78-30-8......................  .........        0.1  .........  .........  .........  .........           X
Triphenyl amine...........................  603-34-9.....................  .........          5  .........  .........  .........  .........  ...........
Triphenyl phosphate.......................  115-86-6.....................  .........          3  .........  .........  .........  .........  ...........
Tungsten (as W)...........................  7440-33-7.
                                            Insoluble compounds..........  .........          5  .........         10  .........  .........  ...........
                                            Soluble compounds............  .........          1  .........          3  .........  .........  ...........
Turpentine................................  8006-64-2....................        100        560  .........  .........  .........  .........  ...........
Uranium (as U)............................  7440-61-1.
                                            Soluble compounds............  .........       0.05  .........  .........  .........  .........  ...........
                                            Insoluble compounds..........  .........        0.2  .........        0.6  .........  .........  ...........
n-Valeraldehyde...........................  110-62-3.....................         50        175  .........  .........  .........  .........  ...........
Vanadium..................................  1314-62-1.
                                            Respirable Dust as V205......  .........       0.05  .........  .........  .........  .........  ...........
                                            Fume (as V205)...............  .........       0.05  .........  .........  .........  .........  ...........
Vegetable Oil Mist........................  N/A.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........

[[Page 61435]]

 
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Vinyl acetate.............................  108-05-4.....................         10         30         20         60  .........  .........  ...........
Vinyl benzene; see Styrene................  100-42-5.
Vinyl bromide.............................  593-60-2.....................          5         20  .........  .........  .........  .........  ...........
Vinyl chloride; see 1910.1017.............  75-01-4.
Vinyl cyanide; see Acrylonitrile..........  107-13-1.
Vinyl cyclohexene dioxide.................  106-87-6.....................         10         60  .........  .........  .........  .........           X
Vinylidene chloride (1,1-Dichloro-          75-35-4......................          1          4  .........  .........  .........  .........  ...........
 ethylene).
Vinyl toluene.............................  25013-15-4...................        100        480  .........  .........  .........  .........  ...........
VM & P Naphtha............................  8032-32-4....................        300       1350        400       1800  .........  .........  ...........
Warfarin..................................  81-81-2......................  .........        0.1  .........  .........  .........  .........  ...........
Welding fumes (total particulate)*........  N/A..........................  .........          5  .........  .........  .........  .........  ...........
Wood dust, all soft and hard woods, except  N/A..........................  .........          5  .........         10  .........  .........  ...........
 Western red cedar.
Wood dust, western red cedar..............  N/A..........................  .........        2.5  .........  .........  .........  .........  ...........
Xylenes (o-, m-, p-isomers)...............  1330-20-7....................        100        435        150        655  .........  .........  ...........
m-Xylene alpha, alpha' diamine............  1477-55-0....................  .........  .........  .........  .........  .........        0.1           X
Xylidine..................................  1300-73-8....................          2         10  .........  .........  .........  .........           X
Yttrium...................................  7440-65-5....................  .........          1  .........  .........  .........  .........  ...........
Zinc chloride fume........................  7646-85-7....................  .........          1  .........          2  .........  .........  ...........
Zinc chromate (as CrO3); see 910.1026. See  Varies with compound.
 Table Z-2 for the exposure limit for any
 operations or sectors where the exposure
 limit in 1910.1026 is stayed or are
 otherwise not in effect.
Zinc oxide fume...........................  1314-13-2....................  .........          5  .........         10  .........  .........  ...........
Zinc oxide................................  1314-13-2.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Zinc stearate.............................  557-05-1.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Zirconium compounds (as Zr)...............  7440-67-7....................  .........          5  .........         10  .........  .........  ...........
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\(30 minutes).

References by Exhibit Number

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Ex. #109: Council Directive on the Protection of the Health and 
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Ex. #110: Directive of the European Parliament and of the Council on 
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Ex. #125: Hazard Communication, 77 FR 17574 (Mar. 26, 2012).
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Ex. #149: 1989 PELs Table. 54 FR 2332, 2923-2959.

[FR Doc. 2014-24009 Filed 10-9-14; 8:45 am]
BILLING CODE 4510-26-P