[Federal Register Volume 69, Number 80 (Monday, April 26, 2004)]
[Rules and Regulations]
[Pages 22402-22441]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-9409]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 9 and 799

[OPPT-2003-0006; FRL-7312-2]
RIN 2070-AD42


In Vitro Dermal Absorption Rate Testing of Certain Chemicals of 
Interest to the Occupational Safety and Health Administration

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY:  EPA is promulgating a final rule under the Toxic Substances 
Control Act (TSCA) that requires manufacturers (including importers) 
and processors of 34 chemicals to conduct in vitro dermal absorption 
rate testing. These chemicals are of interest to the Occupational 
Safety and Health Administration (OSHA) of the Department of Labor, and 
the data obtained under this testing program will be used by OSHA to 
evaluate the need for ``skin designations'' for these chemicals. Skin 
designations are used by OSHA to alert industrial hygienists, 
employers, and workers to the potentially significant contribution to 
the overall exposure to certain chemicals which can occur by the 
cutaneous route. Thus, skin designations encourage employers to 
consider whether changes should be made to processes involving such 
chemical substances in order to reduce the potential for systemic 
toxicity from dermal absorption of these chemicals. Persons who export 
or intend to export any chemical substance included in this final rule 
are subject to the export notification requirements in TSCA section 
12(b).

DATES: This final rule is effective on May 26, 2004. For purposes of 
judicial review, this final rule shall be promulgated at 1 p.m. eastern 
daylight/standard time on May 10, 2004.

ADDRESSES: EPA has established a docket for this action under docket 
identification (ID) number OPPT-2003-0006. All documents in the docket 
are listed in the EDOCKET index at http://www.epa.gov/edocket/. 
Although listed in the index, some information is not publicly 
available, i.e., Confidential Business Information (CBI) or other 
information whose disclosure is restricted by statute. Certain other 
material, such as copyrighted material, will not be placed on the 
Internet and will be publicly available only in hard copy form. 
Publicly available docket materials are available either electronically 
in EDOCKET or in hard copy at the Office of Pollution Prevention and 
Toxics (OPPT) Docket, EPA Docket Center (EPA/DC), EPA West, Room B102, 
1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is 
open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding 
legal holidays. The EPA Docket Center Reading Room telephone number is 
(202) 566-1744, and the telephone number for the OPPT Docket, which is 
located in EPA Docket Center, is (202) 566-0280.

FOR FURTHER INFORMATION CONTACT: For general information contact: Colby 
Lintner, Regulatory Coordinator, Environmental Assistance Division 
(7408M), Office of Pollution Prevention and Toxics, Environmental 
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-
0001; telephone number: (202) 554-1404; e-mail address: [email protected].
    For technical information contact: Keith Cronin or Catherine Roman, 
Chemical Control Division (7405M), Office of Pollution Prevention and 
Toxics, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460-0001; telephone number: (202) 564-8157 or (202) 
564-8172; e-mail address: [email protected] or 
[email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may be affected by this action if you manufacture (defined by 
statute to include import) or process any of the chemical substances 
that are listed in Sec.  799.5115(j) of the regulatory text. Any use of 
the term ``manufacture'' in this document will encompass ``import,'' 
unless otherwise stated. In addition, as described in Unit VI., any 
person who exports or intends to export any of the chemical substances 
in this final rule is subject to the export notification requirements 
in 40 CFR part 707, subpart D. Entities that could be subject to the 
requirements in this final rule may include, but are not limited to:

     Manufacturers (defined by statute to include 
importers) of one or more of the 34 subject chemical substances

[[Page 22403]]

(NAICS 325 and 324110), e.g., chemical manufacturing and petroleum 
refineries.
     Processors of one or more of the 34 subject 
chemical substances (NAICS 325 and 324110), e.g., chemical 
manufacturing and petroleum refineries.

    This listing is not intended to be exhaustive, but rather provides 
a guide for readers regarding entities likely to be affected by this 
action. Other types of entities not listed in this unit could also be 
affected. The North American Industry Classification System (NAICS) 
codes have been provided to assist you and others in determining 
whether this action might apply to certain entities. To determine 
whether you or your business may be affected by this action, you should 
carefully examine the applicability provisions in Unit V.E. and consult 
the regulatory text at 40 CFR 799.5115(b). If you have any questions 
regarding the applicability of this action to a particular entity, 
consult one of the technical persons listed under FOR FURTHER 
INFORMATION CONTACT.

B. How Can I Access Electronic Copies of this Document and Other 
Related Information?

    In addition to EDOCKET (http://www.epa.gov/edocket/), you may 
access this Federal Register document electronically through the EPA 
Internet under the ``Federal Register'' listings at http://www.epa.gov/fedrgstr/. A frequently updated electronic version of 40 CFR part 9 and 
part 799 is available on E-CFR Beta Site Two at http://www.gpoaccess.gov/ecfr/.

II. Background

A. What Action is the Agency Taking?

    In this action, EPA is promulgating a test rule under TSCA section 
4 (15 U.S.C. 2603) which responds to recommendations of the Interagency 
Testing Committee (ITC). Under TSCA section 4(e)(1), the ITC is 
responsible for recommending chemical substances and mixtures to the 
EPA Administrator for priority testing consideration. In September 
1991, the ITC received a nomination from OSHA of 658 chemical 
substances and mixtures for ITC review. OSHA requested that the ITC 
assess the availability of data relevant to dermal absorption for these 
chemical substances and mixtures and determine the need for further 
testing (Ref. 1). OSHA indicated to the ITC that it needed quantitative 
measures of dermal absorption to evaluate the potential hazard of these 
chemicals to workers (Ref. 2). These quantitative measures are 
expressed as the dermal absorption rate for a particular chemical (Ref. 
3, p. 35725). The results of the ITC's review were published in the 
Federal Register (Ref. 1, p. 26900 and Ref. 2, pp. 38492-38493).
    In the 31\st\, 32\nd\, and 35\th\ ITC Reports to the EPA 
Administrator (Refs. 1, 2, and 4), the ITC designated for in vitro 
dermal absorption rate testing a total of 83 of the 658 chemical 
substances nominated by OSHA. A summary of the process by which the ITC 
selected the 83 chemical substances was presented in the proposal to 
this action (Ref. 5, p. 31077). The data reviewed by the ITC included 
data obtained from TSCA section 8(a) and 8(d) rules (Refs. 6, 7, and 8) 
which were promulgated by EPA for the 83 chemical substances included 
in the 31\st\, 32\nd\, and 35\th\ ITC Reports (Refs. 1, 2, and 4). 
These rules required the reporting to EPA of certain production, use 
and exposure-related information, and unpublished health and safety 
data concerning the 83 chemical substances.
    In reviewing the available data, the ITC determined that the data 
for methyl methacrylate, diethyl phthalate, and cyclohexanone would 
meet OSHA's data needs for these three chemicals. Accordingly, the ITC 
withdrew its designation for these three chemicals: Methyl methacrylate 
and diethyl phthalate in the 34\th\ ITC Report (Ref. 3), and 
cyclohexanone in the 36\th\ ITC Report (Ref. 9).
    Eighty of the chemical substances originally nominated by OSHA are 
thus currently designated by the ITC for in vitro dermal absorption 
rate testing under TSCA. In the Federal Register notices containing the 
31\st\, 32\nd\, and 35\th\ ITC Reports (Refs. 1, 2, and 4), EPA 
solicited proposals for TSCA section 4 enforceable consent agreements 
(ECAs) for dermal absorption rate testing of the 80 chemical 
substances. EPA received no proposals for ECAs for dermal absorption 
rate testing in response to these solicitations.
    On April 3, 1996, EPA again solicited interested parties to submit 
proposals for ECAs (Ref. 10). On June 26, 1996, EPA received a proposal 
from the ARCO Chemical Company (ARCO) (Ref. 11) for tert-butyl alcohol. 
On March 26, 1998, EPA received a study from ARCO entitled [\14\C]-t-
Butyl Alcohol: Topical Application: Dermal Absorption Study in the Male 
Rat (Refs. 12 and 12a.). This study was reviewed and found acceptable 
as a means of determining the dermal absorption rate for tert-butyl 
alcohol. Accordingly, EPA did not propose testing of tert-butyl 
alcohol.
    On June 9, 1999, EPA responded to the ITC's designation of the 
remaining 79 chemicals by issuing a proposed test rule under TSCA 
section 4 (Ref. 5) which would require that 47 of these chemical 
substances be tested with respect to in vitro dermal absorption rate. 
The Agency selected the 47 chemicals for testing because, at the time 
of the proposal, EPA believed that their production volumes were the 
highest among the 80 chemicals designated by the ITC. At the time of 
the proposed rule, the most current information available to EPA 
indicated that each of the 47 chemicals was produced in ``substantial 
quantities,'' meaning that their annual production volumes ranged from 
one million to more than one billion pounds. These chemical substances 
were being used in a wide variety of applications, which resulted in 
potential exposures of 1,000 or more workers to each chemical 
substance. Based upon EPA's review of more recent production volume 
data, exposure data, and dermal absorption rate data, which became 
available after the proposal to this rule was published, EPA is now 
requiring testing for 34 of the 47 chemicals that had been included in 
the proposed rule. The rationale for EPA's decision not to finalize 
testing requirements for the other 13 chemicals, which were originally 
proposed for testing, is described in Unit VII.A. through I.
    EPA is requiring that the 34 chemicals be tested according to the 
in vitro dermal absorption rate test standard set forth in Sec.  
799.5115(h) of the regulatory text. EPA has also specified reporting 
requirements in Sec.  799.5115(i) of the regulatory text. EPA may 
pursue testing of the remaining 32 chemicals based on further analysis.
    In the solicitations discussed in this unit (Refs. 1, 2, 4, and 
10), EPA referenced an in vitro dermal absorption rate test method for 
review by potential submitters in developing their proposed protocols 
(Ref. 10, p. 14776). This method was based on the peer reviewed method 
of Bronaugh and Collier (Ref. 13). Some refinements of the method were 
made by a panel of Federal scientists from ITC member and liaison 
agencies (including, for example, Consumer Product Safety Commission 
(CPSC), Department of Defense (DoD), EPA, Food and Drug Administration 
(FDA), National Institute for Occupational Safety and Health (NIOSH), 
and OSHA). EPA received public comments on the method and entered them, 
along with the method itself, into the dockets for the 31\st\, 32\nd\, 
and 35\th\ ITC Reports (docket control numbers OPPTS-41038, OPPTS-
41039, and OPPTS-41042, respectively). In addition, the American 
Chemistry Council (ACC, formerly the Chemical Manufacturers Association 
(CMA)) submitted a proposed protocol outlining

[[Page 22404]]

an alternative method (Refs. 14 and 14a.). Scientists from the Federal 
Agencies represented on the ITC (including EPA and OSHA) reviewed the 
public comments and the ACC proposal. As a result of this review, the 
ITC and EPA scientists further refined the in vitro dermal absorption 
rate test method of Bronaugh and Collier which EPA then proposed to be 
the test standard required by this final rule (Ref. 5).
    The test standard that will be required under this final rule 
describes the procedures for measuring a permeability constant (Kp) and 
two short-term absorption rates (10 minutes and 60 minutes) for 
chemical substances in liquid form. A Kp is useful in estimating skin 
permeation when contact with the chemical is prolonged (hours) and 
steady state is achieved, while a short-term absorption rate 
measurement is more relevant when the contact is short-term (minutes). 
Both measurements are required by the test standard.
    This test standard makes use of established in vitro diffusion cell 
techniques that allow absorption rate studies to be conducted using 
human cadaver skin and either flow-through or static diffusion cells 
(see Sec.  799.5115(h) in the regulatory text). This test standard also 
requires the use of radiolabeled chemical substances unless the test 
sponsor can demonstrate that procedures utilizing a non-radiolabeled 
test substance are able to measure the substance with equivalent 
sensitivity. The first six parameters that are discussed under test 
procedures in Sec.  799.5115(h)(5) of the regulatory text (i.e., choice 
of membrane, preparation of membrane, diffusion cell design, 
temperature, testing of hydrophobic chemicals, and vehicle) are similar 
for the determination of either of the two percutaneous absorption rate 
values (Kp and short-term absorption rate). In contrast, the remaining 
two parameters (i.e., dose and study duration) are different for the 
two percutaneous absorption rate values.
    The in vitro approach was chosen not only for the practical 
considerations that it makes efficient use of labor and materials and 
can easily be performed by a variety of laboratories, but also because 
in vitro diffusion cell studies are necessary for measuring a Kp. 
Although the in vitro method in Sec.  799.5115(h) of the regulatory 
text will satisfy OSHA's data needs to support its skin designations, 
EPA does not believe the method is an adequate substitute for all 
dermal absorption rate testing methods.

B. What is the Agency's Authority for Taking this Action?

    This final rule is being promulgated under TSCA section 4 (15 
U.S.C. 2603), which authorizes EPA to require the development of data 
relevant to assessing the risk to health and the environment posed by 
exposure to chemical substances and mixtures (chemicals).
    Section 2(b)(1) of TSCA (15 U.S.C. 2603(b)(1)) states that it is 
the policy of the United States that:

    adequate data should be developed with respect to the effect of 
chemical substances and mixtures on health and the environment and 
that the development of such data should be the responsibility of 
those who manufacture and those who process such chemical substances 
and mixtures[.]

To implement this policy, TSCA section 4(a) mandates that EPA require 
by rule that manufacturers and/or processors of chemical substances and 
mixtures conduct testing if the Administrator finds that:

    (1)(A)(i) the manufacture, distribution in commerce, processing, 
use, or disposal of a chemical substance or mixture, or that any 
combination of such activities, may present an unreasonable risk of 
injury to health or the environment,
    (ii) there are insufficient data and experience upon which the 
effects of such manufacture, distribution in commerce, processing, 
use, or disposal of such substance or mixture or any combination of 
such activities on health or the environment can reasonably be 
determined or predicted, and
    (iii) testing of such substance or mixture with respect to such 
effects is necessary to develop such data; or
    (B)(i) a chemical substance or mixture is or will be produced in 
substantial quantities, and (I) it enters or may reasonably be 
anticipated to enter the environment in substantial quantities or 
(II) there is or may be significant or substantial human exposure to 
such substance or mixture,
    (ii) there are insufficient data and experience upon which the 
effects of the manufacture, distribution in commerce, processing, 
use, or disposal of such substance or mixture or any combination of 
such activities on health or the environment can reasonably be 
determined or predicted, and
    (iii) testing of such substance or mixture with respect to such 
effects is necessary to develop such data [.]

    The purpose of this testing is to develop data about the 
substance's or mixture's health or environmental effects for which 
there is an insufficiency of data and experience, and which are 
relevant to a determination that the manufacture, distribution in 
commerce, processing, use, or disposal of the substance or mixture, or 
any combination of such activities, does or does not present an 
unreasonable risk of injury to health or the environment.
    Once the Administrator has made a finding under TSCA section 
4(a)(1)(A)(i) (i.e., a finding that a chemical substance may present an 
unreasonable risk of injury to health or the environment) or a finding 
under TSCA section 4(a)(1)(B)(i) (i.e., a finding that a chemical 
substance is or will be produced in substantial quantities and either 
it enters or may reasonably be anticipated to enter the environment in 
substantial quantities or there is or may be significant or substantial 
human exposure to the chemical substance), EPA may require any type of 
health or environmental effect testing necessary to address unanswered 
questions about the effects of the chemical substance. EPA need not 
limit the scope of testing required to the factual basis for the TSCA 
section 4(a)(1)(A)(i) or (B)(i) findings, as long as EPA also finds 
that there are insufficient data and experience upon which to 
reasonably predict the effects of the manufacture, distribution in 
commerce, processing, use, or disposal of such substance or mixture or 
any combination of such activities on health or the environment, and 
that testing is necessary to develop such data. This approach is 
explained in more detail in EPA's statement of policy for making 
findings under TSCA section 4(a)(1)(B) (frequently described as the 
``B'' policy) (Ref. 55, pp. 28738-28739).
    In this final rule, EPA is using its broad TSCA section 4(a) 
authority to obtain dermal absorption rate data necessary for OSHA to 
evaluate the need for ``skin designations'' (see Unit III.B.3.) for the 
34 chemical substances specified in Table 2 in Sec.  799.5115(j) of the 
regulatory text. Following consideration of the public comments 
received by EPA on the proposed test rule (Ref. 5), EPA is making the 
following findings for these chemicals under TSCA section 4(a)(1)(B): 
They are produced in substantial quantities; there is or may be 
substantial human exposure to them; existing data are insufficient to 
determine or predict their health effects; and testing is necessary to 
develop such data.
    EPA has used its TSCA section 4(a) authority in the past to support 
regulatory programs of other EPA offices as well as other Federal 
Agencies needing health and/or environmental effects test data. See, 
e.g., the final test rule for the Office of Water Chemicals (Ref. 68, 
p. 59673).

[[Page 22405]]

III. Response to Public Comments

A. Summary

    EPA received comments on the proposed rule (Ref. 5) from ACC, 
Monsanto Company, First Chemical Corporation, American Forest and Paper 
Association (AFPA), American Petroleum Institute (API), Biphenyl Work 
Group, Diethyl Ether Producers Association (DEPA), Synthetic Organic 
Chemical Manufacturers Association (SOCMA), Acetonitrile Task Force, 
Dupont Dow Elastomers, Fragranced Products Information Network, 
Association of Veterinarians for Animal Rights, People for the Ethical 
Treatment of Animals, Animal Protection Institute Midwest Regional 
Office, Humane Society of the United States, Doris Day Animal League, 
Chlorobenzene Producers Association, Tetrahydrofuran Task Force 
(THFTF), a private citizen, and Union Carbide Corporation (Refs. 15-
33).
    ACC's Naphthalene Panel, Propylene Glycol Ethers Panel, Olefins 
Panel (ACC/O), Hydrocarbon Solvents Panel, Ketones Panel and Oxo 
Process Panel (ACC/KO), and Carbon Disulfide Panel, generally supported 
the comments by ACC (Refs. 34-39). The Chlorobenzene Producers 
Association, Biphenyl Work Group, and the Acetonitrile Task Force, also 
endorsed the comments submitted by ACC. Comments by ACC and those 
comments generally supportive of ACC's comments are collectively 
referred to as ``ACC's'' hereinafter in this document. Comments 
submitted by these groups that are specific to a chemical are 
addressed, as appropriate, in Unit III.F. and in Unit VII.
    A summary of the comments received by EPA on the Proposed Test Rule 
for In Vitro Dermal Absorption Rate Testing of Certain Chemicals of 
Interest to Occupational Safety and Health Administration is included 
in this unit, along with EPA's responses to those comments. The 
comments are available in the public docket for this rulemaking (see 
ADDRESSES).

B. TSCA Section 4 Findings

    1. ``Substantial'' human exposure, TSCA section 4(a)(1)(B)(i)(II)--
a. ``B'' policy. ACC commented that EPA has not provided a sufficient 
basis for its finding of ``substantial'' human exposure under TSCA 
section 4(a)(1)(B)(i)(II), (15 U.S.C. 2603(a)(1)(B)(i)(II)), with its 
approach in this final rule which is based solely on numbers of people 
exposed (more specifically, the number of workers exposed) to each 
chemical. ACC asserts that a substantial human exposure finding must 
additionally be based on information such as each chemical's physical, 
chemical, and biological properties; the manner of use and release; 
exposure concentrations; and duration and frequency of exposure. ACC 
states that neither OSHA's objective of developing skin designations, 
nor EPA's objectives under TSCA, are served by requiring dermal testing 
in circumstances where dermal exposures are at low concentrations, or 
are so infrequent that harm is not likely to occur.
    EPA disagrees with ACC's assertion that EPA has not provided a 
sufficient rationale for its finding that there is or may be 
``substantial'' human exposure to the chemical substances that are 
subject to this final rule as required under TSCA section 
4(a)(1)(B)(i)(II). EPA also disagrees with ACC's contention that EPA 
must consider chemical-specific factors to make a ``substantial'' human 
exposure finding. In its policy statement that explains how EPA 
generally makes findings under TSCA section 4(a)(1)(B)(i) (the ``B'' 
policy), EPA articulated quantitative thresholds to serve as guidance 
in making findings of ``substantial'' production, release, and human 
exposure. (Ref. 55) These quantitative thresholds are based on the 
Agency's belief that it is reasonable to interpret the word 
``substantial'' to mean exposure to large numbers of people. Therefore, 
EPA believes that, in the case of this final rule, where, based on 
information available to EPA (Refs. 5 and 56), 1,000 or more workers 
are potentially exposed to each chemical for which the final rule would 
require testing, it is reasonable to require the testing of each 
chemical. In other words, EPA's policy (as articulated in its final 
``B'' policy statement (Ref. 55)) is that quantitative data alone can 
justify EPA's finding that production, potential release, or the number 
of people potentially exposed to a chemical are ``substantial.'' This 
is consistent with TSCA's goals of ensuring that, given the exposure of 
humans and the environment to a large number of chemical substances and 
mixtures with potentially harmful effects, there is effective 
regulation of commerce in such substances (15 U.S.C. 2601(a)), that 
adequate data be developed with respect to the effect of chemical 
substances and mixtures on health and the environment, and that the 
development of such data should be the responsibility of those who 
manufacture and those who process these substances (15 U.S.C. 2601(b)). 
Affected entities had the opportunity to comment on the proposed rule 
and submit current employee information, readily available to them, to 
refute EPA's finding that a substantial number of employees is exposed. 
In those instances when EPA agreed with information submitted by 
commenters which demonstrated that fewer than 1,000 employees were 
exposed to a chemical, that chemical was not included in this final 
rule (see Unit VII.D., E., and G.)
    A ``substantial'' human exposure finding under TSCA section 
4(a)(1)(B)(i)(II) requires no hazard or risk analysis (Ref. 55, p. 
28742). Given the statutory framework, the legislative history, and the 
case law interpreting the TSCA section 4 testing provisions, EPA does 
not believe that it is required to consider each of the types of 
information described by ACC in order to make a TSCA section 
4(a)(1)(B)(i)(II) ``substantial'' human exposure finding (Ref. 55, p. 
28742).
    Although EPA is not required to consider the factors mentioned by 
ACC in making its ``substantial'' human exposure findings, information 
of the sort described by ACC is nevertheless relevant to other 
decisions leading to a determination as to whether to require testing 
under TSCA section 4. As stated in the Agency's ``B'' policy:

    [f]or each substance-specific rulemaking under section 4, EPA 
must determine whether there are sufficient `data and experience' 
upon which to `reasonably determine or predict' the health and 
environmental effects of a chemical substance, and whether testing 
of such substance is `necessary to develop such data.' In making 
these determinations, the Agency has always, and will continue to 
examine all available and relevant information concerning the 
substance in question, including the physical and biological 
properties of the substance, the manner of its use and release, the 
level, frequency, and duration of exposure, and any available 
relevant exposure and toxicity data. It is the responsibility of 
interested parties to provide any information they believe may be 
relevant to the Agency's determination to require testing of a 
particular chemical substance under TSCA section 4.
(Ref. 55, p. 28743).

In those instances where interested parties provided such relevant 
information on chemical substances prior to the publication of this 
final test rule, EPA and OSHA carefully reviewed the information and, 
based on that review, EPA in some cases decided not to require testing 
for those chemical substances. (See Unit VII.A. through G.).
    b. The National Occupational Exposure Survey (NOES). ACC commented 
that EPA has continued to rely on the NOES database to support its 
findings of ``substantial'' human exposure, a data base which ACC

[[Page 22406]]

believes to be unrepresentative, incomplete, and outdated. ACC states 
that the NOES estimates are greatly overstated and should not be relied 
upon by EPA in making its findings. ACC provided a critique of the NOES 
(Ref. 40) as support for its statements and added that EPA should 
evaluate the level, frequency, and duration of exposure to each 
chemical to determine if it is ``substantial.''
    EPA disagrees with the commenter's statements regarding the 
adequacy of the NOES for supporting a finding of ``substantial'' human 
exposure under TSCA section 4(a)(1)(B)(i)(II). This database contains, 
among other things, useful information on the approximate number of 
workers potentially exposed to a chemical substance specified in the 
database. That is to say, while the survey does not provide meaningful 
information on the level, frequency, or duration of exposure, it is 
useful for providing an estimate of the potential number of workers 
exposed to a chemical. As noted in Unit III.B.1.a., EPA also does not 
agree with the comment that EPA should undertake an exhaustive analysis 
of exposure (i.e., level, frequency, and duration) to a chemical 
substance to find that there is or may be ``substantial'' human 
exposure.
    For each of the chemicals for which testing is required in this 
final rule, estimates of the number of exposed workers were identified 
in the NOES. The NOES was a nationwide data gathering project conducted 
by NIOSH, which was designed to develop national estimates for the 
number of workers potentially exposed to various chemical, physical, 
and biological agents and describe the distribution of those potential 
exposures. Initiated in 1980 and completed in 1983, the survey involved 
a walkthrough investigation by trained surveyors of 4,490 facilities in 
523 different types of industries. Surveyors recorded potential 
exposures when a chemical agent was likely to enter or contact a 
worker's body for a minimum duration. These potential exposures could 
be observed or inferred. Information from these representative 
facilities was extrapolated to generate national estimates of 
potentially exposed workers for more than 10,000 different chemicals 
(Ref. 41). The NOES survey is the most recent and comprehensive source 
of this kind of information.
    In the critique of the NOES cited by ACC, a general conclusion of 
the authors was:

    We conclude from reviewing the survey design that, despite some 
flaws, it represents one of the soundest approaches possible, within 
the limited budget, for attaining national estimates of the number 
of workers in the proximity of potentially hazardous agents.
(Ref. 40).

EPA agrees with this conclusion and believes that it is reasonable to 
use information provided in the NOES database to support a finding of 
``substantial'' human exposure for a chemical substance contained 
within that database.
    In addition, EPA agrees with the authors of the critique, Buell et 
al (Ref. 40), that the survey results, while potentially useful for 
making broad, national estimates of the number of persons in workplaces 
where potentially hazardous agents are also present, should not be used 
to gauge actual worker exposure to these agents, particularly to 
individual chemicals in individual industry sectors. This information 
was not collected in the survey. EPA has relied only on the information 
in the NOES database regarding the approximate number of potentially 
exposed workers in support of its finding of ``substantial'' human 
exposure.
    Because some time has passed since the NOES was completed, EPA 
acknowledges that there may be instances where changes in various 
industrial sectors (i.e., market demand, advances in technology, and 
other mitigating factors) have led to a decrease in the number of 
workers potentially exposed to certain chemical substances. EPA's 
proposed test rule asked interested parties to provide any information 
they believed relevant to the Agency's determination to require testing 
of a particular chemical substance under TSCA section 4. EPA has 
received additional exposure information on certain chemical substances 
for which testing was proposed. This information has been fully 
considered, and for those chemical substances for which EPA believes it 
cannot make the ``substantial'' human exposure finding in light of such 
information, the Agency is not finalizing testing requirements. (See 
Units VII.D., E., and G.).
    c. The Toxic Release Inventory (TRI). ACC stated that it is unclear 
what role the TRI data played in making the TSCA section 4 findings in 
the proposed rule, and that EPA should clarify how environmental 
releases factor into a determination of occupational dermal exposures. 
ACC notes that TSCA section 4(a)(1)(B), makes no mention of 
``release,'' but refers to whether a substance ``enters'' the 
environment. ACC asserts that in the context of TSCA section 4, the 
word ``enter'' connotes presence in the environment. Accordingly, ACC 
argues that ``release'' of a chemical in excess of one million pounds 
per year is not necessarily evidence that the compound ``enters'' the 
environment in ``substantial'' quantities. For example, if a substance 
is dispersed, degraded, or reacted rapidly upon release from 
manufacturing and processing facilities and is never present in 
significant concentrations in air, water, or soil, ACC asserts that it 
has not ``entered'' the environment in ``substantial'' quantities.
    Moreover, ACC contends that environmental release, such as that 
reported under section 313 of the Emergency Planning and Community 
Right-to-Know Act (EPCRA), does not correlate well with dermal exposure 
in the workplace. ACC notes that TRI reports do not indicate the 
concentrations of listed substances in environmental media or the 
extent of their distribution in the environment. Accordingly, ACC 
asserts that the release quantities reported under section 313 of EPCRA 
are not an adequate basis to support a TSCA section 4(a)(1)(B)(i)(I) 
finding in the context of this final rule, and they should not be 
combined with other data on the number of workers potentially exposed 
to support such a finding.
    Although EPA reviewed information contained in the TRI database to 
identify additional support material for the test rule (Ref. 56), EPA 
did not find it necessary to use TRI release data in developing its 
exposure findings for this final rule.
    d. TSCA sections 8(a) and 8(d). API commented that EPA does not 
present results of data gathering in the 1993, 1994, and 1995 TSCA 
section 8(a) and 8(d) rules (Refs. 6-8) for the proposed test rule 
chemicals. API objects to EPA's issuing data gathering rules and then 
not using the data gathered for the purposes of the test rule, 
particularly given that it is 10 years more current than the data that 
EPA used to make its TSCA section 4(a)(1)(B)(i)(II) finding i.e., NOES 
data (Ref. 19).
    Following the EPA Administrator's receipt of the ITC Reports (Refs. 
1, 2, and 4) which designated 83 chemicals for priority testing, the 
EPA's Office of Pollution Prevention and Toxics (OPPT) promulgated TSCA 
section 8(a) Preliminary Assessment Information Reporting (PAIR) and 
TSCA section 8(d) Health and Safety Data rules (Refs. 6-8) for the 83 
chemicals designated for testing by the ITC. The TSCA section 8(a) rule 
required manufacturers and importers of chemicals designated for 
testing by the ITC to submit production

[[Page 22407]]

and exposure reports. The TSCA section 8(d) rule required manufacturers 
(including importers), and processors of chemicals designated for 
testing by the ITC to submit unpublished health and safety studies. 
These rules are automatically promulgated by EPA unless the ITC 
requests that EPA not do so.
    The ITC reviews the TSCA section 8(a) PAIR reports, TSCA section 
8(d) studies, and ``other information'' that become available after the 
ITC adds chemicals to the Priority Testing List. ``Other information'' 
includes TSCA section 4(a) studies, TSCA section 8(c) submissions, TSCA 
8(e) ``substantial risk'' notices, ``For Your Information'' (FYI) 
submissions, ITC-FYI voluntary submissions, unpublished data submitted 
to U.S. Government organizations represented on the ITC, published 
papers, as well as use, exposure, effects, and persistence data that 
are voluntarily submitted to the ITC by manufacturers, importers, 
processors, and users of chemicals recommended by the ITC. The 
submissions are indexed and maintained by EPA. After the ITC reviews 
this information it determines if data needs should be revised, if 
chemicals should be removed from the Priority Testing List, or if 
recommendations should be changed to designations.
    EPA disagrees with the comment that data gathered under TSCA 
section 8(a) and 8(d) rules were not considered in preparing the 
proposal. In fact, the proposed rule described the ITC's use of the 
data from the TSCA section 8(d) rules to support withdrawing its 
designation for three chemicals. As described in the proposal (Ref. 5, 
p. 31077), the ITC received dermal absorption rate data for three 
chemicals after EPA had promulgated TSCA section 8(d) rules for these 
chemicals. The ITC determined that the dermal absorption rate data for 
these three chemicals would meet OSHA's data needs, and accordingly, 
the ITC withdrew its designation for these three chemicals: Methyl 
methacrylate and diethyl phthalate in the 34\th\ ITC Report (Ref. 3, p. 
35725), and cyclohexanone in the 36\th\ ITC Report (Ref. 9, p. 42987).
    Furthermore, the ITC's review of the data gathered under TSCA 
sections 8(a) and 8(d) for the 80 remaining designated chemicals did 
not provide a sufficient rationale for the ITC to make a determination 
that the specified data needs should be revised or that its designation 
of chemicals for in vitro dermal absorption rate testing should be 
withdrawn and those chemicals removed from its Priority Testing List.
    The proposed rule also described EPA's use of production data as a 
basis for its decision to pursue rulemaking on only 47 of the remaining 
80 designated chemicals because of their greater production volumes, 
data which were reported under the TSCA section 8(a) rules (Ref. 5, p. 
31077). Although EPA considered the information on employee exposure at 
manufacturing sites provided in the TSCA section 8(a) submissions, EPA 
also relied on NOES data as they indicate what additional employee 
exposure may occur at processing facilities.
    Finally, for those remaining 32 chemicals designated for in vitro 
dermal absorption rate testing by the ITC which are not addressed by 
this final rule, EPA will present any determinations regarding data 
gathered from TSCA section 8(a) and 8(d), as well as any other 
available data in any future proposal for those chemicals.
    2. ``Data are insufficient,'' TSCA 4(a)(1)(B)(ii). DEPA (Ref. 21), 
the Chlorobenzene Producers Association (Ref. 31), and the Union 
Carbide Corporation (Ref. 47) challenged the Agency's finding that data 
are insufficient to determine a dermal absorption rate for ethyl ether, 
o-dichlorobenzene, and n-amyl acetate, respectively. These commenters 
provided studies to support their claims that available data are 
sufficient to determine dermal absorption rates. ACC (Ref. 15) 
commented that isobutyl alcohol and sec-butyl alcohol are structurally 
similar to other alcohols for which data have been generated and that a 
structure-activity relationship (SAR) approach could be used to predict 
the dermal absorption rates of these two chemicals. EPA reviewed the 
submitted studies and agreed that the available data are sufficient at 
this time to adequately determine or predict dermal absorption rates 
for these five chemicals. See Unit VII.A. through C. and F. for a 
description of the submitted studies and the basis for EPA's decision 
not to pursue rulemaking on these five chemicals.
    3. ``Testing is necessary,'' TSCA section 4(a)(1)(B)(iii). ACC 
commented that EPA failed to demonstrate that the proposed testing is 
necessary to develop data to predict the effects of the chemicals on 
human health and the environment (Ref. 15). ACC also stated that the 
Agency has provided no information on the need for dermal absorption 
data to ``support chemical risk assessments at EPA as well as at other 
Federal agencies.'' As a general matter, ACC believes that EPA should 
not require testing when the Agency has not determined how the data 
will be used, and indeed cannot conclude that testing is necessary in 
such a case. Similarly, API and THFTF (Refs. 19 and 32) requested that 
EPA explain how the Agency (or other Federal Agencies) might use the 
dermal test data.
    EPA believes it has adequately demonstrated a need for the testing 
that will be conducted under this final rule. As discussed in the 
preamble to the proposed rule (Ref. 5, pp. 31076-31078) and in the 
31\st\, 32\nd\, and 35\th\ ITC Reports to the Administrator (Refs. 1, 
2, and 4, respectively), OSHA has found that for many toxic substances 
to which workers are exposed via multiple routes, and specifically for 
the chemical substances for which testing will be required under this 
final rule, very little knowledge exists of the contribution of dermal 
exposure to the total body burden of the substance.
    Dermal absorption rate data for toxic substances encountered in 
industrial and occupational settings are quantitative estimates of the 
rate (amount per specified period of time) at which substances pass 
through the layers of the skin to enter the systemic circulation. OSHA 
assigns a ``skin designation'' to a chemical if it determines that 
cutaneous exposure (through the skin, eyes, and mucous membranes) to 
the chemical may result in systemic toxicity. In order to assign a skin 
designation for a chemical substance, OSHA requires dermal absorption 
rate data. OSHA requested (Refs. 1, 2, and 4) that the ITC help 
identify chemicals which lack sufficient data for OSHA to develop skin 
designations and to use its authority to recommend chemicals for 
priority testing consideration by EPA to obtain these data.
    As described in the proposed rule, the ITC performed searches for 
data relating to the chemicals on the following databases: RTECS 
(Registry of Toxic Effects of Chemical Substances), TOXLINE (TOXicology 
of information onLINE), MEDLINE (MEDlars onLINE), TOXLIT (TOXicology 
LITerature from special sources), CECATS (OPPT/Risk Assessment 
Division/Chemical Screening Branch's Existing Chemical Assessment 
Tracking System), TSCATS (Toxic Substances Control Act Test 
Submissions), and INDEX MEDICUS. The search strategy was designed to 
identify any toxicological tests that used the dermal route of 
exposure. The information from the searches was collected and the 
chemicals were subcategorized based on the number of postings (Ref. 2, 
p. 38493).
    Also as described in the proposed rule, in addition to these 
literature searches, the ITC reviewed data from

[[Page 22408]]

TSCA section 8(a) and 8(d) rules (Refs. 6 through 8) which were 
promulgated by EPA for the chemical substances included in the 31\st\, 
32\nd\, and 35\th\ ITC Reports (Refs. 1, 2, and 4). These rules 
required the reporting to EPA of certain production, use and exposure-
related information, and unpublished health and safety data concerning 
these chemicals. For the 34 chemicals for which in vitro dermal 
absorption rate testing is required under this final rule, there was 
either no dermal absorption rate information available or available 
data were insufficient to derive a dermal absorption rate.
    Testing of the 34 subject chemical substances is necessary to 
develop dermal absorption rate data. Dermal absorption rate data 
derived from testing these 34 chemical substances are needed by OSHA to 
estimate the amount of the chemical substance absorbed after contact 
with the skin. Only when dermal absorption is considered along with 
inhalation exposure data can a more complete and accurate quantitative 
assessment of body burden be estimated. Accurate estimates of body 
burden are necessary to develop assessments of risk to worker health 
posed by exposures to toxic substances in the workplace. This testing 
is needed to determine if the manufacturing, processing, or use of 
these 34 chemical substances presents an unreasonable risk of injury to 
human health.
    In addition to playing an important role in assessing body burden, 
dermal absorption rate data can generate useful quantitative 
information for making recommendations or decisions concerning 
engineering controls or employee use of personal protective clothing to 
prevent exposure by the dermal route. Such information, when considered 
in conjunction with toxicologic and health effects data, can be used by 
industrial hygienists, other occupational health professionals, 
employers, and workers. Dermal absorption information is useful for 
hazard communication and right-to-know purposes, including Material 
Safety Data Sheets, and product labels. Additionally, dermal absorption 
rate data for chemicals used or produced in particular work sites are 
useful in developing comprehensive safety and health programs at those 
facilities.
    OSHA standards, including skin designations, are widely applied and 
referenced. Local, State, and county governments, and other Federal 
Agencies rely on OSHA's occupational standards, as do other national 
governments. It is both appropriate and necessary to require dermal 
absorption rate testing of these industrial chemicals.
    Although OSHA is the primary agency requesting the data that will 
be developed under this final rule, OSHA is not the only Federal Agency 
that will use the data. NIOSH is also very interested in method-related 
issues associated with characterizing dermal exposure and advancing 
improvements in occupational exposure assessments.
    EPA is also interested in data that may be gathered on these 
chemicals. The information obtained by the testing required in this 
final rule may be used to inform the Agency's decisionmaking process by 
providing data which can be used in a preliminary estimate of the 
potential health risk of certain chemical exposures. The 34 chemicals 
for which testing is required under this final rule are part of other 
ongoing Agency efforts. For example, all 34 chemicals are included in 
EPA's High Production Volume (HPV) Initiative (http://www.epa.gov/chemrtk.htm.) In addition, EPA's Voluntary Children's Chemical 
Evaluation Program (VCCEP) (Ref. 43) is designed to provide data to 
enable the public to better understand the potential health risks to 
children associated with certain chemical exposures. Four of the 34 
chemicals are included in EPA's VCCEP: Vinylidene chloride (Chemical 
Abstract Service Registry Number (CAS No.) 75-35-4); p-dichlorobenzene 
(CAS No. 106-46-7); ethylene dichloride (CAS No. 107-06-2); and 
chlorobenzene (CAS No. 108-90-7). (See http://www.epa.gov/chemrtk/childhlt.htm.). While in vitro dermal absorption rate data are not 
being developed under either of these Agency efforts, the data may be 
of benefit in preliminary risk screening, which is the purpose of data 
gathering in the HPV Initiative. Dermal absorption rate data may also 
be beneficial in further consideration of chemicals to which children 
may be exposed. Thus, EPA may use data obtained under this test rule in 
preliminary risk screenings to support its HPV Initiative and VCCEP, or 
for other Agency efforts to protect human health and the environment 
from unreasonable risks resulting from the manufacture, processing, or 
use of chemicals.
    In summary, the data developed under this test rule will assist the 
Agency and others in evaluating these chemical substances for potential 
health or safety risk concerns. Although it is not an independent basis 
for supporting this final rule, as an additional benefit, the data will 
be publicly available, and thus will serve to further the Agency's goal 
of identifying and controlling human health and environmental risks by 
providing greater knowledge to the public.

C. Categories

    ACC (Ref. 15) believes that EPA should consider a category approach 
to dermal absorption rate testing. In reviewing the list of 79 ITC-
designated chemicals, ACC concludes that a great majority can be 
grouped into categories of similar chemical structure and that selected 
chemicals from each category could be tested for the purpose of 
obtaining sufficient data that would allow an accurate prediction of 
dermal absorption rate for other members of the structural group 
through a combination of modeling and quantitative structure activity 
relationship (QSAR) analysis. ACC states that for the designated 
chemicals, these categories would include aliphatic alcohols, ketones, 
aliphatic hydrocarbons, nitroaliphatics, halogenated hydrocarbons, 
aliphatic esters, aromatic hydrocarbons, nitroaromatics, halogenated 
aromatics, amides, aromatic amines, and phenols/phenol ethers. ACC 
suggests that the data generated from testing chemicals within 
categories could then be combined with existing data on other category 
members (including those in the larger group of 658 workplace chemicals 
that were originally nominated for testing by OSHA) to attempt to 
correlate chemical structure with dermal absorption rates.
    EPA disagrees with the category approach suggested by ACC as an 
alternative to the approach proposed by EPA for testing these 
chemicals. ACC has not provided specifics on the number of chemicals in 
each category that would need to be tested and the reason certain 
chemicals would be representative so that reliable structure activity 
predictions could be made. Twelve different structural classes were 
mentioned as potential categories by ACC, but additional classes would 
likely be needed to categorize within the group of 79 chemicals that 
have been designated for testing by the ITC. EPA remains unconvinced 
that the approach suggested by ACC will either minimize the testing 
burden or more efficiently develop data on the chemicals of interest. 
However, the results from the dermal absorption rate testing of the 
chemicals in this final rule could, in appropriate cases, provide 
additional data for more thorough QSAR analysis and better validated 
models for future predictions.

D. Use of Calculated Kps to Screen and Prioritize Chemicals

    ACC commented that adequate data already exist to ``reasonably 
determine

[[Page 22409]]

or predict adverse effects,'' according to TSCA 4(a)(1)(B), for most if 
not all of the chemicals included in the proposed test rule (Ref. 15). 
It is ACC's understanding that the ITC calculated dermal penetration 
rates (Kps) for all of the chemicals covered by the test rule. ACC also 
notes that in 1992, EPA published guidance for estimating Kps for 
organic chemicals (see Ref. 42). The guidance document included 
calculated Kps for 11 of the 47 chemicals proposed for testing. In 
addition, ACC indicates that EPA's 1992 methodology has been largely 
validated, as the calculated Kps closely approximate available 
experimentally determined penetration rates. As such, ACC asserts that 
Kps, estimated using the suggested methodology, would be of sufficient 
quality to be used in screening-level assessments to determine the 
likely influence of dermal exposure on total worker exposure (i.e., the 
need for OSHA skin designations).
    ACC states that EPA should consider giving industry the option of 
using calculated Kp values in lieu of testing, and together with 
industry and OSHA, assess the feasibility of using such data before the 
final rule is promulgated. ACC also states that, at a minimum, EPA 
should consider using calculated Kp data in order to screen and 
prioritize the chemicals for the proposed dermal absorption rate 
testing (Ref. 15). To do this, ACC states that prior to requiring 
testing the available calculated Kp data should be used to screen 
chemicals for their potential to cause systemic toxicity as a result of 
dermal exposure by assessing the potential contribution of dermal 
exposures to total occupational exposures, and that this assessment 
should be used to prioritize testing needs. ACC believes that the 
dermal absorption rate testing should be reserved for those chemicals 
for which screening-level assessments indicate the dermal pathway may 
be of concern. ACC comments that neither OSHA nor EPA has attempted to 
prioritize chemicals using published EPA dermal exposure assessment 
guidance, including published estimated dermal penetration rates.
    EPA disagrees that adequate data exist to ``reasonably determine or 
predict adverse effects,'' according to TSCA 4(a)(1)(B), for the 
chemicals included in the final test rule. As an initial matter, EPA 
believes that measured Kps (i.e., those determined through well 
designed and conducted in vitro or in vivo testing experiments) are 
generally more reliable than calculated Kps, and measured Kps are not 
available for the 34 chemicals subject to this final rule. EPA further 
believes that calculated Kp data may not be sufficiently reliable to be 
used in lieu of testing or in screening-level assessments to prioritize 
testing needs when the most relevant worker exposures involve exposure 
to neat compounds or compounds dissolved in organic solvents. With 
respect to the chemicals for which measured Kps are presented in Table 
5-8 in EPA's 1992 guidance document (Ref. 42), the Kps were measured 
exclusively for the chemicals when they were in aqueous solutions; the 
table presents no measured Kps for neat liquids or chemicals in organic 
solvents, both of which are generally expected to be more relevant to 
the workplace (Ref. 62). Thus, these data are not adequate to provide 
the information needed for OSHA's intended purpose (Ref. 62). However, 
the in vitro testing required by this final rule, in addition to 
developing data needed to assess the potential risk of the 34 subject 
chemicals, will expand the existing data base and allow more thorough 
comparisons of measured Kps with calculated Kps relevant to 
occupational exposures.

E. Comments on Proposed In Vitro Test Standard

    1. General. EPA received comments supporting use of the proposed 
test standard from several groups and individuals (Refs. 25-30). Many 
of these comments were similar in that they supported the standard as a 
means of gathering data without utilizing laboratory animals.
    EPA agrees that there are instances, such as utilizing the test 
standard articulated in this final rule, in which sufficient data on 
the dermal absorption rate of a chemical substance may be gathered 
without using live laboratory animals. EPA considers many factors in 
relying upon specific test methods in its proposals under TSCA section 
4. In specifying the standard for this rulemaking, the ITC and EPA 
considered the views of the public commenters, Federal scientists, and 
laboratories capable of conducting such testing. The standard 
articulated in this rulemaking makes efficient use of labor and 
materials and can be performed in a consistent, economical, and timely 
manner by different laboratories. The specification of the in vitro 
method as the test standard for this final rule also reflects EPA 
efforts to reduce the use of animals, where appropriate, in its testing 
programs. However, as noted previously in Unit II.A., although this in 
vitro method will satisfy OSHA's data needs to support its skin 
designations, EPA does not believe the method is an adequate substitute 
for all dermal absorption rate testing methods.
    2. Technical. In addition to the general comments received by EPA 
on the proposed test standard, EPA also received technical comments 
from ACC, API, THFTF, DEPA, and a private citizen. In general, 
commenters argue that the proposed test standard was unnecessarily 
rigid and that several improvements would provide greater flexibility 
and reduce the cost of testing. EPA and OSHA agree with a number of the 
changes recommended by ACC , API, and THFTF, and have revised the test 
standard accordingly, as described in this unit.
    a. ACC, API, and THFTF commented that both static and flow-through 
in vitro cells have been found acceptable in estimating dermal 
penetration of compounds. EPA agrees. Both static and flow-through in 
vitro cells, as described by the commenters and in the international 
Organization for Economic Co-operation and Development (OECD) draft 
guidance document (Ref. 44), are acceptable for estimating dermal 
penetration of compounds (Ref. 62). EPA has modified the test standard 
at paragraph (h)(5)(iii) to read: ``Either static or flow-through 
diffusion cells must be used in these studies.''
    b. EPA received a comment from a private citizen (Ref. 33) who 
believes that more scientifically valid dermal absorption rates would 
be obtained by using the technologically more advanced flow-through 
type cells and viable human skin instead of the older method using 
static diffusion cells and cadaver skin.
    EPA agrees that in some instances it may be preferable to utilize 
flow-through cell types and viable human skin to generate dermal 
absorption rate data. Based on this comment and similar comments by 
ACC, API, and THFTF, EPA has modified the test standard to allow the 
use of either flow-through cells or static diffusion cells in 
developing the data required under this final rule (See Sec.  
799.5115(h)(5)(iii) of the regulatory text). However, although EPA 
agrees that utilizing viable human skin could provide more reliable 
data, EPA is requiring that human cadaver skin be utilized for all 
testing required in this action. EPA's rationale for this decision is 
described in Unit III.E.2.o.ix.
    c. ACC commented that heat treatment to separate epidermis from 
dermis is an acceptable alternative to dermatome slicing for preparing 
epidermal membranes. EPA agrees. The use of a dermatome prepared skin 
membrane of a thickness of 200 to 500 micrometers (um) is but one 
scientifically acceptable method of preparation. Peeling the epidermis 
from the dermis after heat treatment at 60[deg] C

[[Page 22410]]

for 45 seconds, as recommended by ACC (Ref. 15), or 1 to 2 minutes, as 
specified in the draft OECD guidance document (Ref. 44), is also a 
scientifically accepted means of preparing the test membrane (Ref. 62). 
In response to this comment, EPA specified a time range of 45 seconds 
to 2 minutes as the time for heat treatment to include the two 
recommended treatment times in the ACC and OECD methods (45 seconds and 
1 to 2 minutes, respectively). EPA modified the required test standard 
Sec.  799.5115(h)(5)(ii) to read:

    A suitable membrane must be prepared from skin either with a 
dermatome at a thickness of 200 to 500 micrometers (um), or with 
heat separation by treating the skin at 60[deg] C for 45 seconds to 
2 minutes after which the epidermis can be peeled from the dermis.

    d. ACC and THFTF commented that the requirement that barrier 
properties of human cadaver skin must be pretested with a standard 
compound such as tritiated water prior to conducting the study should 
be expanded to include suitable alternatives to the use of tritiated 
water. (See Howes, et al., Methods for Assessing Absorption, in ECVAM 
Workshop Report 13, J.H. Fentem, ed., European Center for the 
Validation of Alternative Methods, 94-95 (Ispra, Italy 1996)). EPA 
agrees. Membrane integrity checks conducted with transepidermal water 
loss (TEWL) or electrical resistance, as described by the commenters 
and in the OECD guidance document (Ref. 44), are acceptable 
alternatives to dermal penetration of tritiated water for the 
evaluation of human cadaver skin integrity (Ref. 62). EPA has modified 
the test standard in Sec.  799.5115(h)(5)(i)(D) to read:

    Prior to conducting an experiment with the test substance, 
barrier properties of human cadaver skin must be pretested either 
by:
    (1) measuring the movement of a standard compound such as 
tritiated water as discussed, for example, in the reference in Sec.  
799.5115(h)(8)(i),
    (2) determining an electrical resistance to an alternating 
current, at up to two volts, or
    (3) measuring trans-epidermal water loss from the stratum 
corneum.

    e. API, THFTF, and ACC commented that human cadaver skin samples 
can be stored frozen for periods longer than 2 weeks, as proposed by 
EPA. Frozen storage, even for longer periods of time, does not 
adversely affect the integrity of the dermal barrier (see Ref. 45).
    EPA agrees that for purposes of this test rule, the human cadaver 
skin samples can be stored frozen for periods longer than 2 weeks. 
However, EPA does not agree with ACC that skin samples can be frozen 
for up to 18 months without changes in penetration rates for standard 
compounds. EPA does not believe that a single report (Ref. 45) of 
acceptable skin penetration using a single substance (water) with 
membranes frozen for 466 days justifies extending the standard storage 
period to 18 months. Most of the chemicals designated for testing in 
this final rule are organic chemicals with chemical properties quite 
different from water. EPA believes it is reasonable to extend the 
maximum period of time during which human cadaver skin samples can be 
stored frozen (-20[deg] C) to 3 months (Ref. 62). This period of time 
is consistent with OECD guidance (Ref. 44). In response to these 
comments, EPA has modified the test standard in Sec.  
799.5115(h)(5)(ii) to read:

    These epidermal membranes can be stored frozen (-20[deg] C) for up 
to 3 months, if necessary, if they are frozen quickly and the barrier 
properties of the samples are confirmed immediately prior to 
commencement of the experiment.

    f. THFTF commented that EPA should allow a longer, though 
unspecified, amount of time for study completion. THFTF cited three 
circumstances which would make more time necessary:
     The practical ability of companies to test 
multiple materials.
     The availability of contract facilities to 
conduct the testing.
     The extra time needed to synthesize radiolabeled 
material.
    EPA agrees. Circumstances may arise where the proposed 9 months 
would be an insufficient amount of time to complete testing. Therefore, 
EPA is extending the period of time provided to complete the required 
testing from 9 months to 13 months which EPA believes should 
accommodate the circumstances cited by THFTF.
    g. ACC and THFTF noted that the test standard requires a full 
balance sheet to demonstrate recovery of radioactivity. (A ``full 
balance'' refers to a determination of where the radiolabel is present 
at the conclusion of the experiment (i.e., in the receptor fluid, skin 
sample, test vehicle, or diffusion cell) and that the recovery of 
radioactivity in the test system is nearly 100%). Commenters stated 
that it is unclear whether this requirement applies to Kp studies, to 
studies to measure short-term absorption rates, or both. They assert 
that full balance sheets are not necessary for studies in which Kp is 
being determined. Additionally, they commented that small losses of the 
test article do not affect the outcome of the studies because the study 
is, by definition, conducted with an infinite dose. (Infinite dose is 
the amount of test preparation applied to the skin where a maximum 
absorption rate is achieved and maintained because such a volume 
ensures continuous excess of test preparation in the donor chamber.) 
(Ref. 44). Commenters requested that EPA clarify how accounting for 
losses affects Kp values.
    EPA believes the test standard should require that a full balance 
of radioactivity be presented for both Kp and short-term absorption 
rate studies, as proposed. While EPA agrees that small losses of test 
compound are tolerable in the infinite dose design, it is, 
nevertheless, considered good laboratory procedure and does not require 
excessive effort to assess recovery in experiments using radiolabeled 
compound (Ref. 62).
    h. ACC and API (Refs. 15 and 19) commented that the use of 
isopropyl myristate (IPM) as a solvent in the proposed test standard is 
inappropriate. ACC and API stated that IPM, although frequently used as 
a vehicle in various dermatological formulations, has questionable 
applicability in an occupational environment to the chemicals subject 
to this test rule. ACC and API also stated that IPM may not mimic 
workplace conditions and if used, some corrective factor should be 
applied to determine the rate of percutaneous absorption.
    EPA disagrees. IPM is an appropriate all-purpose solvent for the 
rare instances in which certain water insoluble substances capable of 
damaging skin are being tested (Ref. 62). ACC has not provided evidence 
to suggest that use of IPM will generate distorted Kp values 
unrepresentative of occupational settings. If such evidence exists, EPA 
is willing to consider, via the procedures specified at 40 CFR 790.55, 
in vitro percutaneous absorption experiments with other vehicles for 
specific test chemicals, if the test sponsor demonstrates that their 
vehicle is more representative of relevant occupational exposure than 
IPM. EPA will not speculate on what, if any, adjustments might be made 
to Kp values determined by the test standard in order ``to reflect 
realistic exposure scenarios'' or to account for differences in 
regional absorption for skin.
    i. ACC noted that the preamble to the proposed rule indicates that 
the parent chemical and its major metabolites are to be detected in 
certain cases, and requested clarification as to which of the major 
metabolites of the chemicals this requirement applies.
    In the proposal to this action, EPA mentioned that the measurement 
of major metabolites in the receptor fluid

[[Page 22411]]

is done when viable skin is used and significant dermal metabolism is 
anticipated. However, EPA did not propose nor is EPA requiring that 
live skin be used and skin viability be maintained during performance 
of the required tests. Therefore, EPA is also not requiring measurement 
of major metabolites in the receptor fluid. (See Unit III.E.2.o.ix.).
    j. ACC was unsure whether EPA's proposed test standard would 
require the use of 6 or 18 human cadaver skin samples per chemical. EPA 
is requiring a minimum of 18 human cadaver skin samples per chemical. 
EPA has modified the test standard at Sec.  799.5115(h)(5)(i)(B) to 
clarify that data must be obtained from a minimum of six samples for 
each of the determinations, i.e., Kp, 10-minute short-term absorption 
rate, and 60-minute short-term absorption rate. Also, the samples used 
for the testing of a given chemical must come from at least three 
different human subjects, with two samples from each subject being used 
for each determination to allow for biological variation among 
subjects. (See Sec.  799.5115(h)(5)(i)(B) of the regulatory text).
    k. ACC commented that in Sec.  799.5115(h)(5)(v) of the proposed 
regulatory text it is unclear whether it is necessary to demonstrate 
that the concentration of a test substance in the donor chamber has 
remained at greater than 90% of its original value, or that the 
concentration of the test substance in the receptor fluid is less than 
10% of the initial test substance concentration in the donor chamber. 
Similarly, THFTF commented that Sec.  799.5115(h)(5)(v) of the proposed 
regulatory text should be revised to state that physicochemical data or 
experimental results should be used to show that about 10 times the 
concentration in the receptor fluid is achievable under experimental 
conditions. This will ensure that back diffusion is not significant. 
See the OECD Guideline 1999 (Ref. 44).
    EPA has removed the language in question in Sec.  799.5115(h)(5)(v) 
of the regulatory text, and has inserted related text in the test 
standard at Sec.  799.5115(h)(5)(iii) to read:

    To ensure that an increase in concentration of the test 
substance in the receptor fluid does not alter penetration rate, the 
testing laboratory must verify that the concentration of the test 
substance in the receptor fluid is less than 10% of the initial 
concentration in the donor chamber.

This requirement applies to all chemicals to be tested, including 
hydrophobic chemicals.
    l. ACC commented that there is some confusion created by 
inconsistencies between statements in the proposed rule preamble and 
requirements in the proposed test standard. ACC points out that the 
preamble states that ``the measurement of a short-term absorption rate 
is only required when a Kp cannot be obtained using this standard,'' 
whereas Sec.  799.5115(h)(5)(vii)(B) of the proposed regulatory text 
states that ``Short-term absorption rates must be determined for all 
chemicals.'' It is not clear to ACC why short-term absorption rates 
must be determined for all test chemicals. ACC believes that if a 
chemical affects the skin and a Kp value cannot be determined, 
determining a Kp rate is moot. Knowledge of the short-term rate is not 
useful in determining Kp values. API similarly commented that it is not 
clear why determining the short-term absorption rate for each test rule 
chemical is necessary.
    EPA is requiring the measurement of short-term absorption rates for 
all chemicals included in this final rule. The panel of Federal 
scientists that refined the method of Bronaugh and Collier (Ref. 13) 
recommended that all chemicals be tested for short-term absorption in 
order to obtain in vitro dermal absorption rate measurements for brief 
dermal exposures that commonly occur in occupational settings, such as 
spills or splashes. EPA believes that the panel's rationale supporting 
the testing of all chemicals for short-term absorption is reasonable.
    m. ACC and THFTF commented that the correct unit of measurement is 
micrometers, not millimeters, as stated in Sec.  799.5115(h)(5)(ii) of 
the proposed regulatory text. EPA agrees that the correct unit of 
measurement is micrometers, not millimeters. EPA has corrected the test 
standard in Sec.  799.5115(h)(5)(ii) of the regulatory text to reflect 
this.
    n. DEPA argues that the proposed test standard is unacceptable for 
measuring very volatile liquids, such as ethyl ether, because efforts 
to prevent evaporation would lead to unrealistically high pressures, 
leakage of material from the cell, damage to the skin membrane, and 
other substantial technical difficulties. EPA disagrees. DEPA did not 
provide any evidence to suggest, nor is EPA aware, that any such 
problems have ever been reported. However, in those instances where a 
test sponsor can document that closed (i.e., occluded) conditions lead 
to leakage of material or damage to the skin membrane or similar 
technical difficulties, in vitro percutaneous dermal absorption rate 
experiments with the skin surfaces uncovered (unoccluded) may be 
substituted, via the provisions in 40 CFR 790.55, if EPA agrees that 
conducting the study in such a manner is more technically feasible and 
appropriate.
    o. THFTF suggested numerous minor changes to the test standard that 
EPA believes go against either the recommendations of the ITC expert 
panel or TSCA Good Laboratory Practice Standards (GLPS) at 40 CFR part 
792, and do not enhance the validity or acceptability of the method. 
The suggested changes include:
    i. Removing the requirement that the time elapsed between the death 
and harvest of human skin specimens be reported. EPA believes that all 
experimental parameters should be reported in accordance with TSCA 
GLPS, and has retained this requirement in the final rule.
    ii. Removing the requirement that the thickness of the skin 
membrane be reported. EPA believes that all experimental parameters 
should be reported in accordance with TSCA GLPS, and has retained this 
requirement in the final rule.
    iii. Requiring solids to be applied directly to the skin and 
determining percentage absorbed rather than dissolving solids in a 
vehicle and determining Kp. EPA disagrees. Although there may be 
instances where some of the test rule chemicals that are solids at room 
temperature have dermal exposures limited to the chemical in solid 
form, it is also possible based on common industrial practices, that 
there will be occupational exposures to these chemicals when they are 
dissolved or suspended in an aqueous or solvent medium. In addition, 
test solutions are more suitable for determining Kp values for 
chemicals that are solids at room temperature. This is because 
solutions in contact with the skin are uniform and have known 
concentrations, which is not necessarily the case with solids in 
contact with skin (Ref. 63). Therefore, EPA is generally requiring, as 
proposed, that chemicals that are solids at room temperature be 
dissolved in water. If the chemical is hydrophobic and its 
concentration in water is not high enough to obtain a steady-state 
absorption, the chemical must be dissolved in isopropyl myristate. 
However, in those instances where a test sponsor can document that 
occupational exposure is limited to a chemical in solid form, 
development of percutaneous dermal absorption rate experiments with 
solid material may be substituted, via the provisions contained in 40 
CFR 790.55, if EPA agrees that conducting the study in such a manner is 
more appropriate.
    iv. Specifying fixed amounts of test chemical, 10 milligrams per 
centimeter

[[Page 22412]]

squared (mg/cm\2\) for dry solid or 10 microliters per centimeter 
squared (ul/cm\2\) for liquids, be used in short-term absorption rate 
experiments rather than simply requiring the use of sufficient test 
chemical to cover the skin and reporting the quantity used. EPA 
disagrees. It is not necessary to specify that all substances be tested 
at the same fixed volume per skin area. The size of the diffusion 
chamber will partially determine the volume of required test material. 
The important issue is that sufficient test chemical is available to 
completely cover the skin. This is because the absorption rate of a 
chemical is reported per square centimeter of skin, thus, it is 
necessary to precisely ascertain the area of skin contacted (Ref. 63).
    v. Requiring three rather than four absorption measurements for 
determination of Kp. EPA disagrees. The panel of Federal scientists 
that refined the Bronaugh and Collier method (Ref. 13) for use as the 
test standard in this final rule believes that three measurements 
during the steady state absorption period are inadequate to accurately 
determine the Kp and that an additional measurement is necessary for 
this purpose (Ref. 62). As a result, EPA is retaining the requirement 
in this final rule that four absorption measurements be taken for the 
determination of a Kp.
    vi. Specifying that exposure time should be up to 8 hours for 
estimating dermal absorption of finite doses. EPA disagrees. EPA does 
not believe that it will be necessary to test each of the chemicals for 
as long as 8 hours. In fact in many instances, the study can be 
completed in an hour. However, there may be chemicals for which the 
study could require up to 24 hours to complete. Therefore, EPA believes 
that specifying a study duration of up to 8 hours is inappropriate 
(Ref. 63). However, if a test sponsor provides EPA with documentation 
that an alternate exposure time for a specific chemical is more 
relevant than the exposure time specified in this final rule, EPA may 
provide for the substitution of other exposure durations for the 
development of in vitro percutaneous dermal absorption rate 
experiments, via the provisions contained in 40 CFR 790.55, if EPA 
agrees that conducting the study in such a manner is more appropriate.
    vii. Allowing 1:1 ethanol:water to be used as receptor fluid for 
hydrophobic chemicals in addition to 6% polyethylene glycol (PEG) in 
water. EPA agrees that a 1:1 ratio of ethanol to water is a suitable 
receptor fluid for hydrophobic chemicals. However, EPA is specifying 
that the PEG receptor solvent at a concentration of 6% be used for 
testing of hydrophobic chemicals. EPA believes that specifying the use 
of the single PEG receptor solvent for these chemicals should ensure 
more uniform and consistent results. Specifying that a single receptor 
fluid be used for all hydrophobic chemicals will enhance the 
interpretability of test results for these chemicals (Ref. 63).
    viii. Not expressing short-term finite absorption as a rate, i.e., 
micrograms per hour per centimeter squared (ug/h/cm\2\), because the 
true absorption rate is likely to change over the time interval during 
which absorption is being measured. This is to be distinguished from Kp 
determinations at steady state conditions under which there is little 
change in an absorption rate over time. The commenter suggests that 
cumulative amount absorbed per area, i.e., micrograms per centimeter 
squared (ug/cm\2\) is a more appropriate way to express the data.
    EPA disagrees. EPA is aware of the distinctions between a short-
term absorption rate measured under non-steady state conditions and a 
Kp value based on a steady state absorption rate. (See Sec.  
799.5115(h)(5)(vii)(A) of the regulatory text which states that an 
infinite dose must be applied to the skin to achieve a steady-state 
rate of absorption for calculation of a Kp.) Concerning the units to be 
used for short-term absorption rates, EPA does not agree that 
expressing short-term absorption data as cumulative amount per area 
rather than a rate provides any interpretive advantage. A short-term 
absorption rate represents the average absorption over the time 
interval during which it is measured. The true rate will usually be 
greater than the average rate early in the time interval and less than 
the average rate later in the time interval. A determination of 
cumulative amount absorbed per unit of area provides only end of the 
experiment information rather than information about the average rate 
during the course of the test. EPA is requiring that the results be 
expressed as a rate (ug/h/cm\2\), rather than as an amount per area 
(ug/cm\2\) in order to be consistent with rate units used to calculate 
Kp (Ref. 63).
    ix. Allowing the use of human skin obtained from cosmetic surgery 
(breast and/or abdominal skin) as an alternative to human cadaver skin 
for testing. In refining the test method, the ITC and EPA considered 
the collective views of commenters, Federal scientists, and 
laboratories capable of conducting such testing. The test standard 
specifies the use of human cadaver skin which EPA believes makes 
efficient use of labor and materials and can easily be performed by 
many different laboratories. EPA believes that the use of this human 
cadaver skin will provide the desired results in an economical and 
timely manner. Although EPA agrees that a method utilizing viable human 
skin could provide more reliable Kps for compounds in which skin 
metabolism influences dermal penetration, EPA does not believe that 
extensive metabolism is likely, based on the physical chemical 
properties, for the 34 chemicals subject to this final rule. Based on 
the public comments received and discussions with Federal scientists 
and laboratories capable of conducting such testing, EPA believes that 
performing the study with skin from cosmetic surgery could increase 
test costs. As a result, the final test standard requires the use of 
human cadaver skin.
    x. Not requiring the use of radiolabeled materials in the required 
testing because many chemicals subject to the final rule are unlikely 
to be readily available in radiolabeled form. Thus, it will take 
additional time to prepare an adequate supply of radiolabeled 
chemicals, potentially adversely affecting industry's ability to meet 
the regulatory deadlines established for completing the testing and 
submitting the test results.
    EPA disagrees. This comment was in reference to a single chemical 
(tetrahydrofuran) and was the only comment which indicated that 
radiolabeled materials are not available off-the-shelf. EPA believes 
that radiolabeled materials are likely to be available for at least 
some of the other chemicals included in this final rule. In those 
instances where radiolabeled materials are not currently available and 
must be synthesized, EPA believes that the additional amount of time 
provided in this final rule (see Unit III.E.2.f.) is sufficient both to 
prepare such materials and complete the testing. Also, radiolabeling is 
not an uncommon analytical procedure and there are many different 
laboratories (Ref. 46) in the United States that are capable of 
preparing radiolabeled materials. Finally, the test itself is short-
term, generally taking no longer than 24 hours to complete. The Agency 
has provided test sponsors with 13 months to complete the requirements 
established under this final rule. To the extent that a test sponsor 
does require additional time to comply with the final rule, an 
extension from EPA may be requested utilizing the procedures at 40 CFR 
790.55.
    xi. Deleting the word ``live'' as used in Sec.  
799.5115(h)(5)(i)(A) of the proposed regulatory text which states ``the 
most accurate absorption rate data for regulatory concerns related to 
human

[[Page 22413]]

health would be obtained with live human skin.'' In the course of 
developing the final test rule, EPA deleted this statement from the 
test standard primarily for the reasons presented in Unit III.E.2.o.ix.

F. Chemical Specific Comments

    Chemical specific comments on ethyl ether (CAS No. 60-29-7), 
isobutyl alcohol (CAS No. 78-83-1), sec-butyl alcohol (CAS No. 78-92-
2), o-dichlorobenzene (CAS No. 95-50-1), p-nitrotoluene (CAS No. 99-99-
0), beta-chloroprene (CAS No. 126-99-8), n-amyl acetate (CAS No. 628-
63-7), N-isopropylaniline (CAS No. 768-52-5), and o-dinitrobenzene (CAS 
No. 528-29-0) are addressed in Unit VII.
    1. Acetonitrile. The Acetronitrile Task Force commented that the 
total number of workers associated with acetonitrile (CAS No. 75-05-8) 
production in the United States is on the order of 500 (Ref. 23). The 
Task Force believes that EPA has included laboratory personnel in its 
larger estimate as the Agency's figure far exceeds the number of 
personnel involved in manufacturing the chemical. The Task Force notes 
that analytical laboratory personnel are well trained in safely 
handling hazardous materials of this type, and that these workers 
typically handle small volumes of acetonitrile.
    EPA reviewed the Acetonitrile Task Force's estimate of the number 
of workers exposed to acetonitrile at manufacturing sites, but did not 
find that the information provided sufficient basis to conclude that 
there are not substantial numbers of workers potentially exposed to 
acetonitrile during manufacturing, processing, and use. Although EPA 
requested the Acetonitrile Task Force to provide documentation for its 
estimate of the number of workers exposed to acetonitrile, EPA did not 
receive any further information from the Task Force in support of its 
estimate. Also, the NOES data used by EPA did include laboratory 
personnel and EPA believes it is appropriate to include them because 
they are potentially exposed. EPA believes that employee training does 
not assure that exposure will not occur and is no basis for the 
assertion that laboratory employees will have no exposure. EPA also 
believes that the Task Force's estimate that 500 employees are 
potentially exposed may be low if it did not include laboratory 
personnel. Absent specific data indicating otherwise, EPA believes the 
NOES database should be used to estimate worker exposure because it is 
the most recent and comprehensive source of this kind of information. 
Therefore, EPA is requiring the testing of acetonitrile to determine an 
in vitro dermal absorption rate.
    2. Carbon disulfide. ACC's Carbon Disulfide Panel cited three 
studies summarized in an Agency for Toxic Substances and Disease 
Registry (ATSDR) document (Toxicological Profile for Carbon Disulfide 
(August 1996), p. 65-66) as a supporting rationale for its assertion 
that sufficient data exist for carbon disulfide (CAS No. 75-15-0) and 
that testing of carbon disulfide is therefore, unnecessary (Ref. 39). 
One 30-year-old study estimated dermal absorption by measuring very 
small changes in carbon disulfide solution before and after immersion 
of the hand (T. Dutkiewicz and B. Baranowska. 1967. The significance of 
absorption of carbon disulfide through the skin in the evaluation of 
exposure. Toxicology of Carbon Disulfide. Proceedings of a Symposium, 
Prague, 1966, pp. 50-51). EPA reviewed this study and considered the 
methodology flawed due to its indirect measurement and potential 
failure to control for volatilization. In the other two studies cited 
by the Carbon Disulfide Panel (A.E. Cohen, et al. 1958. Skin absorption 
of carbon disulfide vapor in rabbits. I. Associated changes in blood 
protein and zinc. AMA Archives of Industrial Health, 17:164-169; and H. 
Drexler, et al. 1995. Carbon disulfide. 2. Investigations on the uptake 
of CS2 and the excretion of its metabolite 2-
thiothiazolidine-4-carboxylic acid after occupational exposure. 
International Archives of Occupational Environmental Health, 67:5-10), 
EPA notes that a dermal absorption rate was not determined and could 
not be derived using the data gathered (Ref. 62).
    The Carbon Disulfide Panel also cited a dermal absorption rate 
calculated by EPA for carbon disulfide in composted sludge at a level 
of 0.59 milligrams per kilogram (mg/kg) soil. EPA notes that the dermal 
absorption rate was not experimentally determined, but was estimated 
from low environmental levels in composted sludge rather than the 
potentially higher worker exposure to the undiluted liquid (Ref. 62). 
EPA and OSHA do not consider the data cited by the Carbon Disulfide 
Panel to be sufficient to determine a useful and reliable dermal 
absorption rate (Ref. 62).
    The Carbon Disulfide Panel also cited ATSDR's statement that 
``carbon disulfide partitions immediately to the air when released to 
the environment, and does not therefore expose humans to carbon 
disulfide through oral or dermal contact'' (Toxicological Profile for 
Carbon Disulfide (August 1996), pp. 134-141). EPA notes that this 
statement refers to dermal contact with environmental media that had 
been contaminated with carbon disulfide, not to occupational exposure 
(Ref. 62). In fact, the same document makes it clear that the main way 
workers are exposed to carbon disulfide is through the inhalation of 
vapors and dermal contact (Toxicological Profile for Carbon Disulfide 
(August 1996), pp. 9 and 63). Therefore, EPA is requiring the testing 
of carbon disulfide to determine an in vitro dermal absorption rate in 
this final rule.
    3. Naphthalene. ACC's Naphthalene Panel commented that dermal 
toxicity data generated under the Federal Insecticide, Fungicide and 
Rodenticide Act (FIFRA) makes the [proposed] test rule unnecessary 
[with respect to naphthalene] (Ref. 34). The Naphthalene Panel comments 
summarize four unpublished studies submitted under FIFRA to support the 
registration of naphthalene (CAS No. 91-20-3) as an active ingredient 
in moth repellants. One study reports the simulated amount of 
naphthalene that would be deposited on the hands of a homeowner 
handling mothballs. However, the study did not simulate occupational 
exposure and a dermal absorption rate was not measured. The other three 
studies were toxicity investigations in which the test compound was 
topically applied to animals, but none of the studies measured the rate 
of absorption. The toxicity endpoints examined (mortality, body/organ 
weights, hematology, gross tissue examination, skin lesions) related to 
only dermal irritation or advanced systemic effects (Ref. 62). EPA and 
OSHA do not consider the data cited by the Naphthalene Panel to be 
sufficient to determine a dermal absorption rate. Therefore, EPA is 
requiring the testing of naphthalene to determine an in vitro dermal 
absorption rate in this final rule.
    The Naphthalene Panel also commented that EPA's proposed test rule 
for certain Hazardous Air Pollutants (Ref. 48) estimated that 23,092 
workers are exposed to naphthalene, yet, the proposal to this final 
rule estimated that 112,695 workers are exposed to naphthalene. In both 
proposals, EPA cited the NOES as the basis for the estimates. The 
Naphthalene Panel argued that neither figure is correct and that an 
informal survey of Naphthalene Panel members, which comprise the major 
manufacturers and importers of naphthalene, showed that only 
approximately 263 workers are potentially exposed during naphthalene 
manufacturing activities in the United States. The Naphthalene Panel 
also

[[Page 22414]]

argued that the NOES did not obtain information on the frequency, 
concentration, nor duration of worker exposure to naphthalene, and 
therefore EPA should not rely on the NOES to find ``substantial'' or 
``significant'' worker exposure. Furthermore, although the criteria 
stated in EPA's ``B'' policy for finding ``substantial'' human exposure 
may be met (Ref. 55, p. 28746), the Naphthalene Panel believes NOES 
does not show worker exposure to naphthalene at levels that may cause 
health concerns. Moreover, the Naphthalene Panel indicated (without 
providing further specific information) that NOES does not reflect 
current workplace conditions or naphthalene exposure levels.
    EPA acknowledges that different estimates for the numbers of 
workers exposed to naphthalene were cited in the two proposed test 
rules indicated by the commenter and that these estimates were both 
from the NOES. The estimate of 23,092 workers in the Hazardous Air 
Pollutants proposal (Ref. 48) was based on an interim report (Ref. 49) 
compiled in March of 1989. The NOES database was still being updated 
after that time until June 1990, when the final update was completed 
and trade name product resolution ceased. The estimate of 112,695 
potentially exposed workers cited in the proposal to this final rule 
was based on the final update of the NOES. The figure is still the most 
up-to-date NOES information EPA has related to potential worker 
exposure to naphthalene, which includes employee exposure information 
on both manufacturing and processing sites. EPA considered the results 
of the Naphthalene Panel's survey of its members which found that 263 
workers were potentially exposed at their manufacturing sites. However, 
that number does not include an estimate of the number of employees 
potentially exposed to naphthalene at processing sites.
    As stated in Unit III.B.1.a., it is EPA's belief that the 
``substantial'' human exposure finding in TSCA section 
4(a)(1)(B)(i)(II) was intended to address situations in which large 
numbers of people, in this instance, large numbers of workers, may be 
potentially exposed to a chemical substance. EPA is not required to 
make a finding that a chemical substance would pose an unreasonable 
risk of injury at some hypothetical level of toxicity and exposure in 
order to require testing under TSCA section 4(a)(1)(B). See Chemical 
Manufacturers Association v. EPA, 899 F.2d 344, 354-55 (5\th\ Cir. 
1990). EPA has made the necessary findings under TSCA section 
4(a)(1)(B), and EPA is therefore requiring the testing of naphthalene 
to determine an in vitro dermal absorption rate in this final rule.
    4. Biphenyl. The Biphenyl Work Group (BWG) commented that biphenyl 
(CAS No. 92-52-4) currently has two primary uses. Both uses are in 
closed systems either as a chemical intermediate or as a component of 
thermal fluids in highly specialized, closed industrial heat transfer 
systems (Ref. 20). The BWG states that previous industrial uses of 
biphenyl in fruit wrappings and as a dye carrier have been phased out. 
Therefore they state that any exposure to biphenyl is unlikely. The BWG 
asserts that only very low airborne exposures of biphenyl are found in 
manufacturing facilities and facilities using heat transfer fluids. 
They state that, with reference to the biphenyl occupational exposure 
limit of 200 parts per billion (ppb) (29 CFR 1910.1000(a), Table Z-1), 
occupational airborne exposures are very low. The BWG estimated that at 
present, no more than 100 workers are involved in U.S. biphenyl 
production (including maintenance and laboratory personnel) and fewer 
than 100 workers have potential dermal exposure in heat transfer uses.
    EPA reviewed the BWG's estimate of number of workers exposed to 
biphenyl, but did not agree that the information provided sufficient 
basis to conclude that there are not substantial numbers of workers 
potentially exposed to biphenyl (Ref. 67). Although EPA requested the 
BWG to provide documentation for its estimate of the number of workers 
exposed to biphenyl, EPA did not receive any further information from 
the BWG to support its estimate. Absent specific data indicating 
otherwise, EPA believes the NOES database should be used to estimate 
worker exposure because it is the most recent and comprehensive source 
of this kind of information. Therefore, EPA is requiring the testing of 
biphenyl to determine an in vitro dermal absorption rate.
    5. p-Xylene, pentane, nonane, and n-heptane. The Hydrocarbon 
Solvents Panel states that EPA should be able to reliably determine 
dermal absorption rates for untested members of a chemical category by 
comparing the logarithms of their octanol-water partition coefficients 
(log KOW) to those of structurally similar category members 
which have data on dermal absorption rates (Ref. 37).
    The Hydrocarbon Solvents Panel did not provide sufficient detail to 
evaluate its case for a category approach with these four chemicals. 
The Hydrocarbon Solvents Panel also did not provide any data, nor is 
EPA aware of any data, which would provide EPA with a reliable estimate 
of the dermal absorption rate for p-xylene, pentane, nonane, and n-
heptane. Therefore, EPA is requiring testing of p-xylene, pentane, 
nonane, and n-heptane.
    6. p-Dichlorobenzene and chlorobenzene. The Chlorobenzene Producers 
Association cited a number of acute dermal toxicity studies for p-
dichlorobenzene (CAS No.106-46-7) and chlorobenzene (CAS No. 108-90-7) 
to support its position that testing of these chemicals is unnecessary 
(Ref. 31). In addition, the Association cited EPA's Dermal Exposure 
Assessment: Principles and Applications (Ref. 42), which described 
calculated Kps for chlorobenzene and p-dichlorobenzene.
    EPA disagrees with the comment that testing chlorobenzene and p-
dichlorobenzene is unnecessary because existing data on dermal toxicity 
or calculated Kp values are sufficient to reasonably predict the human 
health effects of dermal exposure to these chemicals. None of the 
studies cited by the Chlorobenzene Producers Association for 
chlorobenzene or p-dichlorobenzene specifically measure the dermal 
absorption rate of these chemicals or provide data by which dermal 
absorption rate can be determined. The Kp values cited in the 1992 EPA 
Dermal Exposure Assessment Report for the two chemicals are estimated 
from empirical models and not experimental data and, therefore, do not 
meet OSHA needs. Therefore, EPA is requiring testing of chlorobenzene 
and p-dichlorobenzene to determine an in vitro dermal absorption rate.
    7. Tetrahydrofuran. THFTF commented that quantitative dermal 
absorption data for tetrahydrofuran (CAS No. 109-99-9) are not needed 
by OSHA to establish its skin designations because OSHA has established 
skin designations in the past without such data. THFTF also commented 
that ``current MSDS warnings and product stewardship efforts'' are 
adequately protective against harmful dermal exposure to 
tetrahydrofuran in the workplace (Ref. 32).
    OSHA's current skin designations (29 CFR 1910.1000, Table Z-1) were 
originally recommendations made by the Threshold Limit Value (TLV) 
Committee of the American Conference of Governmental Industrial 
Hygienists (ACGIH) in 1970 or prior to 1970, and adopted without 
reservation by OSHA in 1971. It is true that OSHA was able to set the 
original ``skin designations'' without quantitative dermal absorption 
data. However, OSHA currently believes that now and in the future when 
a skin

[[Page 22415]]

designation is included in a standard that limits occupational 
exposure, it should be supported by a scientific determination of the 
ability or speed of the substance to be absorbed through the skin after 
dermal contact. Because methods are now available to provide this 
information for human skin, OSHA is seeking such testing.
    Regarding ``current MSDS warnings and product stewardship 
efforts,'' EPA agrees with THFTF that these vehicles have been 
important in reducing worker exposures, but they are only as good as 
the scientific data on which they are based. To ensure that the 
exposure limits endorsed by MSDSs are sufficiently protective, dermal 
absorption rate information is needed to better understand the 
contribution to total exposure from the dermal route.
    8. Dipropylene glycol methyl ether. ACC's Propylene Glycol Ethers 
Panel cited a number of acute, subacute, and subchronic toxicity 
studies on dipropylene glycol methyl ether (CAS No. 34590-94-8), 
including studies via the dermal route, to support the position that 
testing this chemical is unnecessary (Ref. 35). None of the studies 
described in the Panel's comments specifically measure the dermal 
absorption rate of dipropylene glycol methyl ether nor can dermal 
absorption rates be derived from the data provided in those studies 
(Ref. 64). Therefore, EPA is requiring testing of dipropylene glycol 
methyl ether to determine an in vitro dermal absorption rate.

G. Laboratory Capacity

    API and THFTF commented that EPA should consider ongoing demands 
for laboratory services. API noted that government and industry are 
currently involved in many testing projects, including the voluntary 
HPV Challenge Program (Ref. 51). API suggested that EPA evaluate 
laboratory capacity and the combined demand that multiple testing 
programs will create. Likewise, THFTF warned of the possibility that 
available laboratory expertise will be overwhelmed by the testing 
required in this final rule.
    In specifying the in vitro dermal absorption rate test standard for 
this rulemaking, EPA concluded that the test standard uses labor and 
materials efficiently and can be performed in the manner described by a 
variety of laboratories. The Agency has conducted, in addition to the 
analysis (Ref. 52) described in the proposal to this rulemaking (Ref. 
5), two more recent studies (Refs. 46 and 53) of laboratory capacity 
associated with its other chemical testing programs. These two studies 
provided further support to EPA's belief that there is sufficient 
laboratory capacity to accommodate the testing which is required by 
this final rule.
    The testing required under this rulemaking is not very complicated. 
The in vitro tests are of short duration, generally taking no longer 
than 24 hours to complete. The Agency has provided test sponsors with 
13 months to complete the requirements established under this final 
rule. EPA does not believe that the relatively modest amount of new 
testing required (a total of three tests on each of 34 chemicals) will 
exceed the available laboratory capacity, particularly given the short-
term nature of the testing, the relatively low cost of the tests, and 
the long time period allowed for completing the studies. Furthermore, 
based on the analyses developed by EPA (Refs. 46, 52, and 53), EPA does 
not believe the cumulative impacts associated with a variety of its 
existing chemical testing programs is likely to overwhelm the available 
laboratory expertise as suggested by API and THFTF.

H. Export Notification

    Several issues raised in comments relate to EPA's implementation of 
TSCA section 12(b) (15 U.S.C. 2611(b)) export notification requirements 
for chemicals for which the submission of data is required under TSCA 
section 4. Section 12(b) of TSCA states, in part, that any person who 
exports or intends to export to a foreign country a chemical substance 
or mixture for which the submission of data is required under TSCA 
section 4 must notify the EPA Administrator of such export or intent to 
export. The Administrator in turn will notify the government of the 
importing country of EPA's regulatory action with respect to the 
substance. EPA's regulations implementing TSCA section 12(b) are at 40 
CFR part 707, subpart D.
    As a general matter, comments on the scope of EPA's regulations 
under TSCA section 12(b) are beyond the scope of this rulemaking. 
However, three comments associated with the requirements under TSCA 
section 12(b) do merit some discussion in this preamble.
    1. Application to chemical in any form. ACC commented that EPA's 
statement in its proposed rule that export notification requirements 
would apply to exporters of the chemical substances subject to the 
final rule regardless of the form (e.g., byproduct, impurity) in which 
they are exported constitutes an unprecedented expansion of the TSCA 
section 12(b) notification requirements.
    EPA disagrees with this comment. TSCA section 12(b) and the 
implementing regulations at 40 CFR part 707 apply, in part, to the 
export or intended export of a chemical substance for which the 
submission of data is required under TSCA section 4. Neither the 
statutory nor the regulatory language restricts this requirement to 
exporters of chemical substances and mixtures in particular forms, but 
instead generally extends export notification requirements to exporters 
of chemical substances and mixtures without regard to the form in which 
the chemical substances and mixtures are being or will be exported. The 
language in the proposed rule and in this final rule are not an 
expansion of the TSCA section 12(b) notification requirements. It is 
noted, however, that the Agency did not intend to change the current 
export notification provisions affecting articles which specify that no 
export notification is required for articles, except polychlorinated 
biphenyl articles, unless required in specific section 5, 6, or 7 
rules. See 40 CFR 707.60(b).
    2. Exporters subject to notification requirement. ACC states that 
TSCA section 12(b) limits the imposition of export notification 
requirements related to TSCA section 4 actions to persons who actually 
have testing obligations under TSCA section 4. EPA disagrees. TSCA 
section 12(b)(1) and the implementing regulations at 40 CFR part 707, 
subpart D apply to any person who ``exports or intends to export to a 
foreign country a chemical substance or mixture for which the 
submission of data is required under [TSCA section 4].'' (15 U.S.C. 
2611(b)(1)). Under 40 CFR 707.65(a)(2)(ii), exporters must notify EPA 
of their first export or intended export to a particular country when 
data are required under TSCA section 4. EPA believes the language 
unambiguously requires notification of export by exporters of 
substances which are the subject of TSCA section 4 actions regardless 
of whether the exporters themselves are also subject to the underlying 
TSCA section 4 rules. Thus, exporters of a chemical substance that is 
covered by data submission requirements under TSCA section 4, including 
persons who are not otherwise subject to the TSCA section 4 rule itself 
as manufacturers and/or processors, are subject to export notification 
requirements under TSCA section 12(b).
    3. Information collection request (ICR). API suggests that, because 
this final rule will result in the requirement that export 
notifications are submitted to EPA for exports or intended exports

[[Page 22416]]

of the substances covered by the final rule, this is a new information 
collection activity that requires OMB review (Ref. 19). Furthermore, 
API believes that EPA's cost estimates for TSCA section 12(b) 
notification ignores the biggest costs associated with export 
notification, which are the internal training and systems necessary to 
identify exports against the export notification list, tracking of what 
notifications have already been submitted and to what countries, and so 
forth. These system costs are magnified when business operations change 
(e.g., sales, acquisitions, and so forth) and export notification 
systems need to be adjusted accordingly.
    EPA disagrees that this action is a new collection of information 
requiring OMB review. The information collection activities related to 
export notification under TSCA section 12(b)(1) are approved under OMB 
control number 2070-0030 (EPA ICR No. 0795). The methodologies, 
assumptions, and estimates developed by EPA for implementation of TSCA 
section 12(b) have been reviewed under notice and comment procedures 
during the development of the ICR. EPA believes it would be more 
appropriate to address API's burden concerns in the context of the ICR 
renewal process and therefore will not respond to them in the context 
of this final rule.

I. Persons Required to Test

    EPA stated in the proposed rule that manufacturers and processors 
of the chemical substances included in the final rule would be subject 
to the final rule. As in the past, under the procedures set forth at 40 
CFR part 790, the persons subject to the final rule fall into one of 
two groups, designated here as Tier 1 and Tier 2. Persons in Tier 1 
(those who would initially have to comply with the final rule) would be 
obligated either to: Submit to EPA letters of intent to conduct 
testing, conduct this testing, and submit the test data to EPA or apply 
to and obtain from EPA exemptions from testing. Persons in Tier 2 
(those who would not have to initially comply with the final rule) 
would not need to take any action unless they are notified by EPA that 
they are required to do so. Persons in Tier 1 who obtain exemptions and 
persons in Tier 2 would nonetheless be subject to providing 
reimbursement to persons who actually conduct the testing.
    Under 40 CFR part 790, EPA traditionally has treated the following 
persons as being in Tier 2 in TSCA section 4(a) test rules:
     Processors (40 CFR 790.42(a)(2)).
     Manufacturers of less than 500 kg (1,100 lbs) 
per year (``small-volume manufacturers'') (40 CFR 790.42(a)(4)).
     Manufacturers of small quantities for research 
and development (``Research and Development (R&D) manufacturers'') (40 
CFR 790.42(a)(5)).
    In the proposed test rule, EPA reconfigured the tiers in 40 CFR 
790.42 by adding the following persons to Tier 2: Byproduct 
manufacturers; impurity manufacturers; manufacturers of naturally 
occurring substances; manufacturers of non-isolated intermediates; and 
manufacturers of components of Class 2 substances. The Agency also 
proposed that persons who do not know or cannot reasonably ascertain 
that they are manufacturing or processing the chemical substances 
included in the final rule would not be subject to the final rule.
    EPA's proposed approach to the ``persons required to test'' portion 
of this test rule was intended to clarify subject entities' obligations 
under the final rule and focus the testing requirements initially on 
those entities whom EPA believes would be most likely to conduct 
testing (Ref. 5, pp. 31080-31082). EPA solicited comment on this new 
approach to the ``persons required to test'' portion of the test rule, 
and received a number of comments. After considering these comments, 
EPA has decided to finalize the approach as proposed, with the addition 
of provisions related to the ``subtiering'' of Tier 2 entities (see 
Ref. 5, pp. 31081-31082, and Unit III.I.3.).
    1. General agreement with EPA's ``persons required to test'' 
approach. All the commenters on the new approach to the ``persons 
required to test'' section of the proposed rule agreed that 
manufacturers of byproducts and impurities and processors are 
appropriately placed in Tier 2. These commenters also agreed that the 
persons EPA has put in Tier 1 are appropriately placed in Tier 1. API 
stated that the approach in the proposed rule ``appropriately focuses 
the rule, will reduce burden and complexity, and will facilitate timely 
accomplishment of testing.'' API also agreed with the Agency's 
rationales for tiering. AFPA stated that the new ``persons required to 
test'' approach would provide greater certainty to people about what 
they must do under the final rule.
    ACC/O and ACC/KO additionally agreed with the inclusion of 
manufacturers of components of Class 2 substances in Tier 2. API agreed 
with the exclusion of manufacturers or processors who do not know or 
cannot reasonably ascertain that they are manufacturing or processing a 
test rule substance.
    2. EPA should retain the ability to move Tier 2 groups to Tier 1. 
AFPA, ACC/O, and ACC commented that EPA should retain the flexibility 
to move Tier 2 groups to Tier 1 on a case-by-case basis. For example, 
if certain processing activities cause special risks, then processors 
could be brought into Tier 1 upfront in the proposed rule. If case-
specific justifications exist for moving Tier 2 entities to Tier 1, EPA 
should state these justifications publicly.
    EPA agrees that the Agency should retain the ability to elevate 
Tier 2 entities to Tier 1 on a case-specific basis in future test 
rules, and where the Agency takes such an action, it will state its 
justification(s) for doing so. For example, if EPA is able to determine 
that a chemical is manufactured solely or primarily in the form of a 
byproduct, EPA may propose to include persons who manufacture that 
chemical as a byproduct in Tier 1, even though byproduct manufacturers 
of other chemicals listed in the same proposed rule might otherwise be 
included in Tier 2. EPA does not agree, however, that risk should be a 
basis for moving entities from Tier 2 to Tier 1 (see Unit III.I.4.).
    EPA will continue to retain flexibility over the status of entities 
covered by Tier 2 consistent with EPA's flexibility over the narrower 
group of entities that have been included in Tier 2 in previous test 
rules; processors, small-quantity manufacturers (i.e., manufacturers of 
less than 500 kg (1,100 lbs.) of a test rule chemical), and R&D 
manufacturers (40 CFR 790.42(a)(2), (a)(4), and (a)(5), respectively). 
In the final rule which established the general Tier 2 status of small-
quantity and R&D manufacturers and processors in test rules, EPA stated 
that it ``reserves the right to differ from the general procedure in 
this final rule by proposing in a specific TSCA section 4 test rule to 
require R&D manufacturers and/or small-quantity manufacturers to submit 
exemption applications'' (Ref. 69, p. 18882). EPA will also continue to 
retain the ability to elevate, on a case-specific basis, R&D 
manufacturers, small-quantity manufacturers, and processors, from Tier 
2 to Tier 1. The concept that flexibility can be built into test rules 
in general is suggested by 40 CFR 790.2, which states in part that 
``the procedures for test rules are applicable to each test rule in 
part 799 of this chapter unless otherwise stated in specific test rules 
in part 799 of this chapter.''
    The Agency does not intend to specifically identify all individual 
Tier

[[Page 22417]]

2 entities. Rather, these entities would self-identify via the 
submission of letters of intent to test or exemption applications. EPA 
expects that, similar to the arrangements typically developed when Tier 
1 entities are under an obligation to conduct testing, if Tier 2 
entities are required to conduct testing, it would generally be to 
their benefit to reach agreement on who will actually conduct the 
testing. The Agency believes that it is unlikely that Tier 2 entities 
will be required to conduct testing under this final test rule, a view 
that is shared by ACC which stated that:

    [ACC] is not aware of any substance covered by the testing 
proposal for which there is likely to be no Tier 1 producer who 
comes forward [to conduct testing]. Indeed, ACC is not aware of any 
instance in the past where not a single person initially required to 
comply with a test rule came forward, such that EPA was required to 
notify other persons of their obligations under the test rule.

    EPA intends to follow the procedures laid out in the regulatory 
text if it becomes necessary for EPA to call upon persons in Tier 2 to 
conduct testing. In other words, if EPA does not receive a letter of 
intent to test from any Tier 1 entities, the Agency will publish a 
Federal Register notice to alert Tier 2 entities to the requirement 
that they submit letters of intent to test or exemption applications.
    3. Do not subdivide Tier 2 as a general matter, instead subdivide 
Tier 2 on a case-by-case basis. In the proposed rule, EPA solicited 
comments on subdividing Tier 2 to enable the Agency to prioritize which 
persons in Tier 2 would be required to perform testing, if needed. ACC 
and API suggested that EPA should not subdivide Tier 2 entities as a 
general matter, for all test rules. They commented that, if EPA 
considers requiring Tier 2 entities to conduct testing, the Agency 
should first determine whether in fact there are no Tier 1 entities, 
and reevaluate whether the proposed testing is still necessary. If Tier 
1 manufacturers do not conduct testing and the testing is still 
necessary, then EPA should identify upfront which persons in Tier 2 
will be required to test. ACC suggests that subtiering the Tier 2 
entities could be done on a case-by-case basis as needed, based on the 
activities that give rise to the need for testing. API argues that 
there is no basis for distinguishing processors from the various types 
of manufacturers included in Tier 2, therefore there is no 
justification for subtiering the Tier 2 entities.
    Despite these comments, and although EPA does not anticipate a need 
for Tier 2 entities to conduct testing under this final rule, EPA has 
decided to subdivide the Tier 2 entities upfront in this final rule 
(see Unit V.E.3.e.). Subdividing Tier 2 upfront in test rules may 
facilitate compliance by requiring Tier 2 manufacturers, when required 
to comply, to submit letters of intent to test or exemption 
applications before processors are called upon to do so. The Agency's 
expectation is that it may generally be less administratively complex 
for manufacturers to conduct the testing (including coordinating 
efforts to determine who will actually conduct testing) than for 
processors to do so. This is because there are generally fewer 
manufacturers (even as byproducts, impurities, etc.) than processors. 
EPA also believes that testing costs have traditionally been passed by 
manufacturers along to processors, and has not received evidence to the 
contrary. The Agency does not believe at this time that it can justify 
a subdivision of Tier 2 entities other than between Tier 2 
manufacturers and processors. For example, EPA does not believe it 
would be appropriate to base a subdivision on the activities that give 
rise to the need for testing (see, e.g., Unit III.I.7.).
    4. Persons who solely manufacture and/or process non-isolated 
intermediates or naturally occurring substances should not be subject 
to rules under TSCA section 4. Commenters provided several reasons for 
completely exempting these manufacturers from test rule coverage. 
Certain commenters believe that these entities have never been covered 
by test rules in the past, and were specifically excluded under the 
amended proposed rule for hazardous air pollutant (HAP) chemicals (Ref. 
70). These commenters pointed out that non-isolated intermediates are 
exempt from Premanufacture Notification (PMN), the Inventory Update 
Rule (IUR), PAIR, and general TSCA section 8(a) requirements. One 
commenter indicated that production of non-isolated intermediates does 
not contribute to the need for testing or present the same concerns as 
do other substances introduced into commerce, thus manufacturers of 
non-isolated intermediates should not be considered subject to test 
rules. Another commenter suggested that EPA has discretion under TSCA 
section 4 to specify the classes of persons subject to or exempt from a 
test rule based on its rationale for requiring testing. The comments 
suggest, however, that where EPA has case-specific justification(s) 
(for example, chemical-specific hazard or exposure concerns related to 
the manufacture of non-isolated intermediates or naturally occurring 
substances are demonstrated), these categories of manufacturers could 
be appropriately included as subject to a rule.
    EPA does not believe that it would be appropriate to fully exempt 
manufacturers and processors of non-isolated intermediates and 
naturally occurring substances from rules under TSCA section 4. 
Instead, it is generally appropriate to include such entities as 
persons subject to TSCA section 4 test rules because they are 
considered manufacturers and processors under TSCA and should be 
included among those responsible for conducting testing or providing 
fair and equitable reimbursement to those who have conducted testing. 
As a general matter, however, EPA intends to place manufacturers of 
non-isolated intermediates and naturally occurring substances in Tier 2 
in test rules unless, for example, the Agency believes such 
manufacturers are responsible for a disproportionate share of the 
production volume of a test rule substance, in which case EPA may place 
them in Tier 1.
    The plain language of the statute indicates that testing 
responsibilities under TSCA section 4(b)(3)(B) are not restricted to 
those who manufacture or process a test rule chemical for limited uses. 
Nor is EPA required to demonstrate that particular types of 
manufacturing or processing contribute to the need for testing (i.e., 
that a particular type of manufacture plays a direct role in increasing 
risk, in the case of a rule based on a TSCA section 4(a)(1)(A) finding, 
or in increasing exposure, in the case of a rule based on a TSCA 
section 4(a)(1)(B) finding). See TSCA section 4(a). The statute 
indicates that if EPA finds that the effects associated with 
manufacture, distribution in commerce, processing, use, or disposal 
cannot reasonably be determined or predicted (see TSCA section 
4(a)(1)(A)(ii) and 4(a)(1)(B)(ii)), then manufacturers and/or 
processors are generally required to test (see TSCA section 
4(b)(3)(B)). For example, the final TSCA section 4 rule for biphenyl 
(Ref. 77, pp. 37184-37185) stated that TSCA section 4 testing 
responsibilities are not restricted to only those who manufacture or 
process a test rule chemical for certain uses. Rather, the persons who 
manufacture and/or process (depending on the findings made) a test rule 
chemical are generally subject to the requirements of a final test 
rule.
    In order to ensure that reimbursement of the entity(ies) conducting 
testing is equitable, as a general matter, EPA does

[[Page 22418]]

not believe that it is appropriate for classes of entities otherwise 
potentially subject to a rule to be dropped from all rule-related 
obligations (with the exception of persons who do not know or cannot 
reasonably ascertain that they manufacture or process a test rule 
substance). There may be circumstances, not present here, when it would 
be equitable to exempt additional entities from all test rule 
obligations, but that determination would need to be made on a case-by-
case basis.
    Persons who solely manufacture a chemical in the form of a non-
isolated intermediate are generally exempt from the TSCA section 5 PMN 
regulations (40 CFR 720.30(h)(8)), the TSCA section 8(a) IUR (40 CFR 
710.30(c)), the TSCA section 8(a) PAIR (40 CFR 712.25(d)(2)), and the 
general TSCA section 8(a) regulations (40 CFR 704.5(d)) for reasons 
particular to those regulations. However, this does not preclude EPA 
from treating these persons as manufacturers of chemical substances for 
purposes of other provisions of TSCA, including TSCA section 4. For 
example, EPA has stated that:

    chemical substances [which are not intentionally removed from 
the equipment in which they were manufactured] are considered to be 
manufactured or processed for a commercial purpose for the purposes 
of section 8 of the Act.
(Ref. 71, p. 64588).

EPA believes it is generally appropriate to include manufacturers of 
non-isolated intermediates and naturally occurring substances as 
persons subject to TSCA section 4 test rules in order to ensure that 
reimbursement of those who paid the costs of testing is equitable. TSCA 
section 4(c)(3)(A) requires EPA to order ``fair and equitable'' 
reimbursement for test costs under the Agency's reimbursement 
regulations. Consistent with this purpose, EPA's current ``persons 
required to test'' approach distributes the burden of testing and 
reimbursement equitably among the persons who manufacture and/or 
process test rule substances, with an exemption for persons who do not 
know or cannot reasonably ascertain that they manufacture or process a 
test rule substance.
    Even if it were relevant to the question of who is subject to a 
TSCA section 4 test rule, EPA disagrees with the assertion that the 
manufacture of non-isolated intermediates does not present any 
exposure-related concerns. While the amount of chemical substance 
released as a result of this type of production may generally be 
expected to be less than is released as a result of other production, 
manufacturing or processing a chemical as an intermediate does not 
preclude exposure to that chemical. See Office of Solid Waste final 
test rule (Ref. 72, p. 22305). The production of non-isolated 
intermediates presents concerns related to acute exposures, from, e.g., 
spills, leaks or transfers. In addition, as EPA stated in the test rule 
for Office of Solid Waste chemicals:

    It is common experience that process waste streams and reactor 
vessel residues will contain ``intermediates.'' In many instances, 
these chemicals are released to the environment as fugitive 
emissions, liquid or solid wastes, and as unreacted feedstock 
(impurities) in finished products. As such, ``intermediates'' 
typically exist as chemicals to which there is potential for human 
exposure.
(Ref. 72, p. 22305).

    EPA believes that, although a person's manufacture of a chemical in 
the form of a non-isolated intermediate may provide a lesser exposure 
concern than the manufacture by other persons of the same chemical in 
other forms, an appropriate accounting of responsibility is provided 
for in the determination of fair and equitable reimbursement under 
TSCA, when necessary. TSCA section 4(c)(3)(A) states that ``all 
relevant factors'' must be considered by EPA in the promulgation of 
rules for the determination of reimbursement. Pursuant to this 
provision, EPA established mechanisms in its general reimbursement rule 
to allow, as needed, for the case-specific consideration of factors 
such as exposure to a chemical as a result of each subject person's 
manufacturing and/or processing activities. See 40 CFR 791.40(a).
    Finally, manufacturers and processors of non-isolated intermediates 
and naturally occurring substances have been subject to test rules in 
the past, except as proposed in the amended proposals for the testing 
of certain hazardous air pollutants (HAPs). (Ref. 73, pp. 19696, 19699 
and Ref. 70, pp. 67470, 67481). EPA is not adopting the approach taken 
in the HAPs proposals for this final rule and, as described in Unit 
V.E., is taking a different position here. TSCA section 4(a) requires 
testing if findings have been made with regard to certain activities 
involving chemical substances or mixtures, and, under TSCA section 
4(b)(3)(B), manufacturers and/or processors must conduct such testing 
if findings have been made. TSCA does not distinguish among 
manufacturers and processors of different forms/production types of a 
chemical substance or mixture; all are generally subject to the 
requirements of TSCA section 4.
    5. ``Manufacturers of test substances as components of Class 2 
substances'' should not be included among the persons subject to the 
final rule. In the proposed rule, EPA stated that manufacturers of test 
substances as components of Class 2 substances would be among those 
entities that would be subject to the final rule, but not initially 
required to comply (i.e., Tier 2). Class 2 substances are chemical 
substances having a chemical composition that cannot be represented by 
a specific, complete chemical structure diagram, because such a 
substance generally contains two or more different chemical species 
(not including impurities) (see 40 CFR 720.45(a)(1)(i)). The Agency 
received a number of comments debating the appropriateness of the 
proposed Tier 2 status of manufacturers of components of Class 2 
substances.
    a. ACC and API (Refs. 15 and 19) commented that components of Class 
2 substances are not considered under TSCA to have been 
``manufactured'' in their own right unless they have been separated 
from the Class 2 substance.
    EPA disagrees. The Agency considers a substance to be manufactured 
for purposes of TSCA section 4 even if it is manufactured as a 
component of another chemical substance, and regardless of its 
isolation from other components of the combination. EPA maintains that 
to be regulated under a TSCA section 4 action (for which findings have 
been made that allow EPA to cover manufacturers), a manufacturer must 
be a ``manufacturer'' as defined by TSCA section 3, and manufacture a 
chemical substance (or mixture) that is subject to a test rule. Under 
TSCA section 3(7):

    [t]he term `manufacture' means to import into the Customs 
territory of the United States (as defined in general headnote 2 of 
the Tariff Schedules of the United States), produce, or manufacture.

There are no limitations in the definition of ``manufacture'' or in 
TSCA section 4 to suggest that if a person imports, produces, or 
manufactures a test rule substance as part of a complex combination of 
substances (i.e., a Class 2 substance), as opposed to an isolated 
component, then the person is not a manufacturer of that test rule 
substance. Therefore, EPA considers a chemical substance to be 
manufactured and subject to coverage under TSCA section 4 even if it is 
manufactured as a component of another chemical substance, and 
regardless of its isolation from other components of the combination.

[[Page 22419]]

    EPA has used the term ``Class 2 substance'' as a way to describe 
variable composition substances and complex combinations of substances 
which can separately be considered ``chemical substances'' under TSCA. 
If a Class 2 substance is a chemical substance as defined by section 
3(2)(A) of TSCA, then EPA may regulate the Class 2 substance itself. 
Neither the designation of a particular substance as a Class 2 
substance, nor EPA's authority to regulate it as a distinct chemical 
substance under the Act, changes the fact that it may contain any 
number of individual components which may also be ``chemical 
substances'' as defined by TSCA, and therefore, also be subject to 
EPA's regulatory authority under the Act. See, especially, TSCA section 
3(2)(A), which identifies among the set of substances that are 
``chemical substances'':

    . . . any organic or inorganic substance of a particular 
molecular identity, including any combination of such substances 
occurring in whole or in part as a result of a chemical reaction or 
occurring in nature. . .

Thus, if appropriate TSCA section 4(a)(1) findings are made with regard 
to manufacturing, distribution in commerce, use, and/or disposal 
activities for a chemical substance, then manufacturers of that 
substance are subject to the test rule according to TSCA section 
4(b)(3), regardless of whether they manufacture the substance as a 
component of a Class 2 substance or in some other manner.
    This is consistent with the position set forth in the proposed 
methylcyclopentane (MCP) and commercial hexane test rule, stating that:

    . . .manufacturers and processors of MCP or commercial hexane 
who do so in the course of producing gasoline or other motor or 
heating fuels are subject to this rule because the Agency's. . 
.findings are based on the manufacture, processing, and use of MCP 
and commercial hexane.
 (Ref. 75, p. 17864-17865).

Gasoline is a Class 2 substance; commercial hexane is a Class 2 
component of gasoline and MCP is one of its C6 isomer 
components. In the final rule, EPA dropped the testing requirement for 
MCP, but kept the requirement for manufacturers of commercial hexane, 
stating that ``[i]f health effects are positive for commercial hexane, 
then EPA may consider testing the C6 components 
individually'' (Ref. 76, pp. 3387-3388).
    The Agency acknowledges that it has not explicitly required persons 
who manufacture test substances as components of Class 2 substances to 
comply with certain test rules in the past. However, the Agency does 
believe that these persons are manufacturers for purposes of TSCA 
section 4, and hence are subject to test rules where appropriate 
findings are made under TSCA sections 4(a)(1) and in accordance with 
TSCA section 4(b)(3).
    b. ACC (Ref. 15) commented that EPA should clarify that it will 
continue to treat Class 2 substances as distinct chemical substances 
(with components that are not regulated under the PMN and other TSCA 
regulations) regardless of the ``persons required to test'' approaches 
taken in the OSHA dermal and HAPs proposed rules.
    The approach to the identification of ``persons required to test'' 
that is being adopted in this final test rule, and which may be applied 
in other, future test rules, is not intended to modify the status of 
any chemical substance or entity under other existing TSCA regulations.
    c. API (Ref. 19) commented that Tier 2 should include 
``manufacturers of Class 2 substances that contain a test rule 
substance'' rather than ``manufacturers of components of Class 2 
substances.''
    EPA disagrees with this suggested change, and has not implemented 
it in this final rule. The Agency believes it has the authority under 
TSCA section 4 to regulate both manufacturers of Class 2 substances 
themselves (for example, by requiring the testing of a Class 2 
substance by manufacturers of that Class 2 substance) and manufacturers 
of test substances as components of Class 2 substances (for example, by 
requiring the testing of a chemical substance by manufacturers that 
produce or import that chemical substance as a component of a Class 2 
substance). In this final test rule, persons in the former group are 
included in Tier 1 of the grouping of persons required to test, whereas 
persons in the latter group are included in Tier 2.
    d. API (Ref. 19) commented that manufacturers of Class 2 substances 
should not be considered manufacturers of the myriad components in the 
Class 2 substances unless they isolate a component chemical, for a 
number of reasons:

     Class 2 substances are distinct chemical 
substances that are complex and variable in composition, and the Class 
2 nomenclature is accurate and useful for representing them.
     A Class 2 stream may contain a substance as a 
component at some times but not at others.
     Applying TSCA rules to Class 2 substances, 
rather than to their individual components, does not compromise 
protection of human health and the environment.
     Because many components of Class 2 substances do 
not add commercial value to the products, manufacturers of Class 2 
substances may not be aware of the presence of test rule substances as 
components.

    As stated in Unit III.I.5.a., EPA does not agree that manufacturers 
of components of Class 2 substances should only be regulated under TSCA 
section 4 if they isolate a component substance that is subject to the 
test rule. TSCA section 4(b)(3)(B) generally provides the authority for 
the Agency to include all manufacturers and/or processors in the scope 
of test rules, regardless of whether they isolate a test rule substance 
from a Class 2 substance.
    The inclusion of manufacturers of test substances as components of 
Class 2 substances as persons subject to this final test rule is not 
intended to reflect any finding, or determination on the part of EPA 
that there is a direct connection between a specific manufacturing 
activity and the potential human health and/or environmental hazards or 
risks that may be associated with the test rule substance. See also 
biphenyl final test rule (Ref. 77, pp. 37184-37185). Their inclusion as 
persons subject to the rule is intended to facilitate the fair and 
equitable distribution of burden of testing and reimbursement among the 
persons who manufacture and process test rule substances. For example, 
there may be cases where large quantities of a component of a Class 2 
substance are manufactured, such that the quantity of a particular non-
isolated component (that is the subject of a TSCA section 4 test rule) 
is far greater than the quantity of the same chemical substance 
manufactured in isolated form by other persons.
    The concern that ``because many components of Class 2 substances do 
not add commercial value to the products, manufacturers of Class 2 
substances may not be aware of the presence of test rule substances as 
components'' is addressed by the provision in this final test rule 
which exempts persons from testing obligations where their status as 
manufacturers or processors of a particular substance is not ``known to 
or reasonably ascertainable by'' them.
    In response to the comment noting that persons may be aware of the 
presence of a component of a Class 2 substance in a stream at some 
times but not others, EPA believes that the reimbursement process under 
TSCA

[[Page 22420]]

section 4 and the implementing regulations at 40 CFR part 791 address 
the concern; under these provisions, if utilized, persons would be 
required to provide fair and equitable contributions to test costs. The 
circumstance of a substance that is known to be produced at only 
certain times and not others may be a consideration under that process.
    e. API (Ref. 19) commented that requiring manufacturers of Class 2 
substances to test components of Class 2 substances that are also test 
substances would be a departure from past regulatory practice under 
TSCA section 4.
    EPA disagrees with the commenter's statement that requiring 
manufacturers of Class 2 substances to test components that are also 
test substances that the person manufactures would be a departure from 
past regulatory practice under TSCA section 4. EPA acknowledges that in 
general its past practice has not been to impose explicit obligations 
under TSCA section 4 on persons who manufacture a test substance as a 
component of a Class 2 substance, unless that person isolates the test 
substance from the Class 2 substance, although as discussed in Unit 
III.I.5.a., there have been exceptions.
    However, EPA did not explicitly require testing by manufacturers of 
test substances as components of Class 2 substances in certain previous 
test rules in part because EPA had determined in light of comments 
received on the proposals that testing of the Class 2 substance itself 
would be more appropriate than requiring testing on the individual 
components of Class 2 substances. See the discussion of the commercial 
hexane test rule (Ref. 76) in Unit III.I.5.a. In another case, EPA 
declined to require testing by manufacturers of components of Class 2 
substances in a final test rule because it believed that it had 
provided insufficient notice that such manufacturers would be subject 
to the test rule. See the clarification to the final test rule covering 
certain ``Office of Water chemicals'' (Ref. 78).
    As discussed previously, however, TSCA sections 4(c)(3)(A) and 
4(c)(4)(A) require EPA to order, where necessary, ``fair and 
equitable'' reimbursement from manufacturers and processors for test 
costs incurred by those who are developing, or who have submitted the 
required test data. EPA believes that fairness and equity can be best 
facilitated by including within the pool of persons from whom 
reimbursement can potentially be sought all persons who can be 
considered manufacturers or processors under TSCA, subject to narrow, 
clear exemptions. EPA believes that persons who manufacture test 
substances as components of Class 2 substances are ``manufacturers'' 
under TSCA section 4, and generally should not be exempt from inclusion 
among those from whom reimbursement could potentially be sought.
    6. Create a de minimis exemption. API suggests that EPA provide a 
de minimis exemption like the exemption provided in the amended 
proposed HAPs rules (Ref. 70, pp. 67470, 67481 and Ref. 73, pp. 19696, 
19699) for manufacturers and processors who solely manufacture or 
process test rule chemicals in amounts less than 1% in a mixture.
    EPA is not adopting this suggestion in this final rule. The final 
rule contains an exemption from all responsibilities associated with 
the final rule for persons who do not know or cannot reasonably 
ascertain that they manufacture or process a test rule substance. The 
final rule also provides Tier 2 status to manufacturers of small-
quantities (less than 500 kg/1,100 lb per year or solely for R&D), 
those who manufacture the test substance as a byproduct, impurity, 
naturally occurring substance, non-isolated intermediate, or component 
of a Class 2 substance, and all processors. With respect to 
manufacturers of small quantities who manufacture the test substance as 
a component of a Class 2 substance, the 500 kg/1,100 lb cutoff applies 
to the manufacture of the test substance, not the Class 2 substance. 
EPA believes that these provisions supply sufficient relief from test 
rule requirements to lower volume manufacturers and processors. These 
groups are still subject to reimbursement, however, and they would also 
potentially be subject to testing.
    To the extent that persons who manufacture a test rule chemical in 
amounts less than 1% in a mixture are not covered by the ``known to or 
reasonably ascertainable by'' exemption, and are not otherwise included 
in Tier 2, they are initially required to comply with the final test 
rule. EPA believes that Tier 1 status is appropriate for these 
manufacturers, who produce or import at least 500 kg/1,100 lb of a test 
rule chemical each year, and who know (or who could reasonably 
ascertain) that they are manufacturing the chemical.
    7. In determining who is responsible for conducting testing, EPA 
should consider the data needs the rule is intended to fill and the 
role of specific manufacturing and processing activities in creating 
the exposure scenarios the rule is intended to evaluate. ACC commented 
that under TSCA section 4(b)(3)(B), responsibility for conducting 
testing may be imposed on those manufacturers and/or processors engaged 
in activities for which EPA has determined that available data and 
experience are insufficient under TSCA section 4(a). Thus, EPA's 
approach to the ``persons required to test'' section in a given test 
rule should depend on the data needs the rule is intended to fill, and 
the role of the specific manufacturing and processing activities in 
creating the particular human or environmental exposure scenarios which 
the rule is intended to evaluate.
    TSCA does not limit the persons subject to a test rule solely to 
specific classes of manufacturers and/or processors based on the data 
needs the rule is intended to fill, or based on the role of the 
specific manufacturing and processing activities in creating particular 
exposures. Rather, persons who manufacture and/or process (depending on 
the findings made) a test rule chemical are generally subject to the 
requirements of the test rule. TSCA section 4(b)(3)(B). See also 
biphenyl final test rule (Ref. 77, pp. 37184-37185), which states that 
testing responsibilities under TSCA section 4 are not restricted to 
only those who manufacture or process a test rule chemical for certain 
uses.
    EPA agrees that certain limited exemptions for persons who would 
otherwise be subject to test rules may be appropriate. However, in 
order to fully exempt a group of persons otherwise covered by a test 
rule from responsibilities under the test rule, EPA's view is that 
there must be an adequate justification for doing so that is consistent 
with the intent of the statute, and that is applicable only to those 
persons who it is proposing to exempt, and not any others. For example, 
in this final rule EPA is exempting manufacturers and processors who 
``do not know or cannot reasonably ascertain'' that they are 
manufacturing or processing a test rule chemical (see Sec.  
799.5115(b)(2) of the regulatory text).
    Exempting individual entities or classes of entities from test rule 
requirements on the basis of a determination that their activities do 
not relate in some direct way to the data needs the rule is intended to 
fill or to the exposure scenarios addressed by the rule is not 
consistent with the intent of the statute. Such exemptions would likely 
result in the need for multiphase rulemaking, and may in most cases not 
be possible from a practical standpoint given that EPA often would not 
have enough information to make such determinations. In addition, 
exempting

[[Page 22421]]

certain individual entities or classes of entities from test rule 
requirements increases the potential that the burden of testing and 
reimbursement would be distributed in an inequitable manner among the 
persons who manufacture and process test rule substances. The Agency 
believes it is appropriate to generally require manufacturers and/or 
processors of a test rule chemical to be subject to a rule, rather than 
to fully exempt individual manufacturers or processors or certain 
classes of manufacturers or processors from test rule responsibilities.
    8. Tier 2 should not be subject to reimbursement. AFPA, API, ACC/O, 
ACC/KO, and ACC commented that subjecting Tier 2 entities to 
reimbursement would, in large part, eliminate the benefit associated 
with having a tiered approach. EPA should only require Tier 2 entities 
to reimburse if they are required to conduct testing in the absence of 
testing commitments from Tier 1 entities.
    EPA does not agree. In order to ensure that test sponsors have the 
ability to seek equitable reimbursement, Tier 2 entities are subject to 
reimbursement regardless of whether the entities included in Tier 1 
complete the testing required under the rule. EPA addressed this issue 
in the context of its May 7, 1990 rule amending the testing procedural 
rule by adding certain groups of manufacturers to Tier 2. EPA stated 
the following in the final rule:

    Some commenters suggested that chemicals produced solely for R&D 
[research and development] purposes should be excluded altogether 
from TSCA section 4 rules. Thus, rather than placing R&D 
manufacturers in a ``second tier,'' they would not be legally 
subject unless specified in a particular test rule... EPA does not 
believe that it should grant a total exemption to R&D manufacturers. 
TSCA section 4 gives EPA authority to require testing of chemicals 
manufactured for R&D. Congress did not exempt R&D manufacturers from 
being subject to TSCA section 4, as in the case of [rules under] 
sections 5 or 8 of TSCA. In this rule, EPA has lifted the procedural 
burden imposed on R&D manufacturers by test rules, recognizing that 
test sponsors would rarely, if ever, seek reimbursement from R&D 
manufacturers. By maintaining legal authority over R&D 
manufacturers, however, EPA has reserved the right of a test sponsor 
to seek reimbursement from all persons legally subject to a test 
rule.
 (Ref. 69, p. 18883).

    The final rule amending the testing procedural rule indicates that 
persons in Tier 2 are subject to the requirement to conduct testing 
under a test rule during the period from the effective date of the test 
rule to the end of the reimbursement period, but will not generally be 
required to submit letters of intent to test or exemption applications 
unless no other manufacturer of the chemical submits a letter of intent 
to test (Ref. 69, p. 18882). In addition, persons in Tier 2 will be 
required to submit letters of intent to test or exemption applications 
if a problem occurs with the initiation, conduct, or completion of the 
required testing or the submission of the required data with respect to 
a chemical substance included in the test rule.
    However, although Tier 2 entities are subject to providing 
reimbursement, EPA's experience under previous test rules has been that 
persons who manufacture the largest quantities of a test rule substance 
have generally found it to be in their best interest to develop cost-
sharing arrangements (which typically do not include all persons 
subject to providing reimbursement) to cover the costs of testing, 
rather than attempting to reach an agreement regarding reimbursement 
among the broader group made up of all persons potentially subject to 
providing reimbursement, or soliciting the involvement of the Agency 
under the reimbursement regulations at 40 CFR part 791 in developing a 
reimbursement arrangement. The development of such private cost-sharing 
arrangements appears to avoid possible difficulties that could be 
associated with coordinating the larger group of all persons 
potentially subject to reimbursement under a test rule, and provides 
flexibility to the parties to the arrangement because it may take any 
form they choose. If the parties are unable to agree upon a cost-
sharing arrangement, they may contact EPA and initiate formal 
reimbursement procedures under 40 CFR part 791. These procedures would 
include all persons subject to the rule, i.e., all entities from both 
Tier 1 and Tier 2.
    Other comments related to the issue of reimbursement by Tier 2 
entities are listed below:
    a. Persons not initially required to comply with a test rule have 
never been required to reimburse before (ACC, ACC/O, API). EPA 
disagrees. Since 1990, EPA has included processors, small-quantity 
manufacturers (i.e., manufacturers of less than 500 kg (1,100 lbs.) of 
a test rule chemical), and R&D manufacturers in Tier 2 (See 40 CFR 
790.42(a)(2), 40 CFR 790.42(a)(4), and 40 CFR 790.42(a)(5), 
respectively). As a result, for the last decade these entities have 
been considered subject to test rules, but not initially required to 
comply with the requirement that letters of intent to test or exemption 
applications be submitted to EPA. Shifting groups of manufacturers and/
or processors to Tier 2 does not ``change the legal rights and 
obligations of persons subject to TSCA section 4 test rules, but would 
only eliminate some of the paperwork burden associated with 
compliance.'' (Ref. 69, p. 18882). In fact, persons included in Tier 2 
``would still be subject to test rules (and export notification 
requirements as specified in TSCA section 12(b)), and would not be 
exempt from reimbursement claims.'' (Ref. 69, p. 18882).
    The Agency shifted R&D and small-quantity manufacturers to Tier 2 
based on its recognition that, in practice, the administrative costs of 
seeking reimbursement from these entities would likely exceed the 
reimbursement that might be gained by their participation. Therefore, 
the filing of exemption applications by R&D and small-quantity 
manufacturers serves no practical purpose (i.e., there is no need for 
them to self-identify by submitting exemption applications). As 
discussed in the proposed rule, processors were originally put in Tier 
2 for another reason, i.e., manufacturers would not likely seek 
reimbursement directly from them, but would rather pass their costs on 
to processors indirectly via the market. In addition, the large numbers 
of processors would create administrative difficulties in making 
testing decisions (Ref. 5, p. 31081).
    Persons who are subject to a test rule, but who are not initially 
required to comply with the test rule have always been potentially 
subject to reimbursement under the formal reimbursement procedures at 
40 CFR part 791. For example, see the interim final rule amending the 
procedural rule at 40 CFR part 790 (Ref. 74, p. 20654), which states 
that, where manufacturers and processors are subject to a test rule, 
processors will automatically be given a conditional exemption from the 
requirement that letters of intent to test or exemption applications be 
submitted to EPA. This exemption is conditional because it would be 
lifted if none of the persons initially required to comply with the 
rule (i.e., manufacturers) submit a letter of intent to test. In 
addition, processors may be required to provide reimbursement directly 
to those sponsoring the testing.
    Although Tier 2 entities are subject to reimbursement under this 
final test rule and have been subject under past test rules (see final 
rule amending the testing procedural rule at 40 CFR part 790 (Ref. 69), 
EPA believes that they have not historically participated in 
reimbursement because other manufacturers have always created cost-

[[Page 22422]]

sharing arrangements that did not require their involvement.
    b. Tier 1 manufacturers should be those persons who undertake the 
activities that, for the most part, give rise to the need for testing. 
As a result, they should be the only ones responsible for 
reimbursement. EPA should identify upfront in a rule the persons whose 
activities warrant their contribution to the cost of testing. All of 
these persons should be included in Tier 1, and reimbursement should 
only apply to those Tier 1 persons (unless EPA has to resort to 
requiring entities in Tier 2 to submit letters of intent to test/
exemption applications, and then Tier 2 would have to reimburse also) 
(API). Entities in Tier 1 that obtain an exemption in lieu of testing 
should generally be the only persons responsible for reimbursing. EPA 
should retain flexibility to impose costs on Tier 2 entities when 
circumstances warrant (ACC, ACC/O).
    Under TSCA section 4(b)(3)(B), once EPA has made the requisite 
regulatory findings with respect to a chemical, ``each person'' who 
manufactures (or intends to manufacture) and/or processes (or intends 
to process) the chemical ``shall'' be required to conduct tests and 
submit data. Tier 2 entities have ``automatic conditional exemptions'' 
from the requirement that they conduct testing (see Sec.  
799.5115(c)(3) of the regulatory text). TSCA sections 4(c)(3) and 
4(c)(4) indicate that persons granted exemptions from the requirement 
that testing be conducted and data submitted may be required to 
reimburse the costs of testing under reimbursement regulations 
promulgated by the Agency if the persons subject to the rule do not 
otherwise agree on the amount and method of reimbursement. As a result, 
although EPA initially exempts Tier 2 entities from requirements 
associated with testing and the submission of data, these entities are 
not exempt from the requirement that they reimburse the costs of 
testing.
    EPA does not believe TSCA provides flexibility to impose 
reimbursement obligations on Tier 2 entities only when it makes a 
determination that the circumstances warrant it, or based on 
determinations as to whether particular manufacturers/processors or 
specific groups of such entities undertake activities that relate 
directly to the rationale for requiring testing. TSCA section 4 
indicates that testing responsibilities are not restricted to those who 
manufacture or process a test rule chemical in certain forms (such as 
restricting the requirements of the rule only to Tier 1 entities). 
Rather, persons who manufacture and/or process (depending on the 
findings made) a test rule chemical are generally subject to the 
requirements of a final test rule. TSCA section 4(b)(3)(B). See also 
biphenyl final test rule (Ref. 77, pp. 37184-37185). EPA has created an 
exception to this general approach solely for persons who do not know 
or who cannot reasonably ascertain that they manufacture and/or process 
a test rule chemical.
    c. Reimbursement requirements should only apply to persons who may 
be required to conduct tests and submit data, i.e., Tier 1 (ACC).
    All persons included in either Tier 1 or Tier 2 may be required to 
reimburse the costs of testing because all manufacturers and processors 
of the chemical substances included in this final test rule are subject 
to the final test rule. As the reimbursement regulations (promulgated 
pursuant to TSCA section 4(c)(3)(A)) provide: ``[p]ersons subject to a 
test rule have an obligation ... either to test or to obtain an 
exemption and pay reimbursement'' (40 CFR 791.2(a)). Tier 2 entities 
have automatic conditional exemptions from testing requirements, as 
discussed earlier. Although Tier 2 entities are not as likely to be 
required to conduct testing as Tier 1 entities, both groups are 
responsible for reimbursing the person(s) who actually conduct testing.
    d. EPA's proposed extension of reimbursement obligations to Tier 2 
entities might complicate future efforts to conduct testing under ECAs 
(ACC, ACC/O).
    EPA is not significantly changing the status quo with regard to 
reimbursement obligations established under previous TSCA section 4 
regulations. Persons in Tier 2 under previous test rules have been 
subject to providing reimbursement. See the final rule amending the 
testing procedural rule at 40 CFR part 790 (Ref. 69). The primary 
effect of the approach to ``persons required to test'' that was 
proposed and is being adopted in this final rule is to better focus the 
set of persons included in Tier 1, and to expand and clarify the set of 
persons included in Tier 2. EPA is unaware of any reason to believe 
that this approach to ``persons required to test'' will make it more 
difficult to develop ECAs.
    e. EPA has said that manufacturers of impurities, byproducts, and 
components of Class 2 substances have not historically participated in 
testing or reimbursement. This is true of all other entities included 
in Tier 2 under this final rule. Extending reimbursement to Tier 2 
disregards this experience (ACC, ACC/O).
    EPA agrees that manufacturers of impurities, byproducts, components 
of Class 2 substances, and all other entities included in Tier 2 under 
this final rule have probably not historically participated in testing 
or reimbursement. However, the likely reason they have not participated 
is because the costs of testing under test rules promulgated to date 
have been contributed to by a smaller group of entities subject to the 
rule (the larger manufacturers of each test rule substance), without 
the need for EPA's involvement. EPA anticipates that similar cost-
sharing arrangements would continue to occur under this final rule and 
other rules using this revised approach to ``persons required to 
test,'' as they offer significant advantages to the persons subject to 
the rule. If EPA were to become involved in reimbursement via the 
reimbursement procedures at 40 CFR part 791, then all Tier 1 and Tier 2 
manufacturers and processors would be included in those proceedings.
    9. EPA should clarify that the approaches to the ``persons required 
to test'' sections in the OSHA dermal and HAPs proposed rules will not 
affect the applicability of requirements under TSCA programs outside 
those implementing TSCA section 4. ACC/O and ACC commented that where a 
particular group (e.g., manufacturers of non-commercial byproducts) is 
currently exempt under certain TSCA regulations, it should continue to 
be exempt under those regulations regardless of the ``persons required 
to test'' approach taken in test rules under TSCA section 4.
    The approach the Agency takes in the ``persons required to test'' 
portion of any given test rule is not intended to affect the status of 
persons under regulations other than those relevant to the given test 
rule.

J. Economic Impact Analysis

    API noted that EPA's Economic Impact Analysis estimates 
administrative costs only for companies initially required to comply 
with the final test rule (companies in Tier 1). API believes that this 
analysis is inappropriate if EPA pursues imposing reimbursement 
obligations on Tier 2 entities. If reimbursement obligations are 
imposed on Tier 2 companies, API asserts there will be associated 
administrative, negotiation, and other costs that EPA should include in 
its analysis.
    EPA disagrees with this comment. Although Tier 2 entities are 
subject to reimbursement, EPA's experience under past test rules has 
been that Tier 1

[[Page 22423]]

persons have found it to be in their best interest to develop cost-
sharing arrangements among themselves to cover the cost of testing. The 
development of such private cost-sharing arrangements appears to avoid 
possible difficulties that could be associated with coordinating a 
larger group of persons subject to reimbursement under a test rule, and 
provides maximum flexibility to the parties to the arrangement. Because 
manufacturers in Tier 1 have been identified for each subject chemical 
(see discussion of economic analysis in Unit VIII. (Ref. 57)), EPA 
expects that at least one such person will comply with the testing 
requirements. EPA is not aware of any circumstances in which Tier 1 
entities have sought reimbursement from Tier 2 entities either through 
private agreements or by soliciting the involvement of the Agency under 
the reimbursement regulations at 40 CFR part 791. Given this consistent 
experience with previous TSCA testing actions, EPA does not believe 
that there will be any administrative, negotiation, or any other costs 
associated with seeking reimbursement from Tier 2 companies.

K. Definition of Small Business

    In the preamble of the proposal to this rule (Ref. 5), EPA 
requested comment on whether the Agency should establish an alternative 
small business definition to use in the small entity impact analyses 
for future TSCA section 4(a) test rules, and what size cutoff may be 
appropriate.
    SOCMA commented that the most appropriate definition to use in 
conducting small entity analyses for TSCA section 4(a) test rules is 
the employee-based definition established by the U.S. Small Business 
Administration (SBA), which for most industries classifies firms as 
small based on the number of employees in the firm. The SBA set the 
numerical threshold for what is considered small on an industry-by-
industry basis. SOCMA believes that this definition provides EPA with a 
straightforward and appropriate distinction between small and large 
companies that are closely related to a company's total annual sales. 
SOCMA also commented that it does not believe that an alternative 
approach, such as the small business definition from TSCA section 8 
would be appropriate for conducting impact analyses for TSCA section 
4(a) test rules. However, SOCMA believes if EPA were to pursue a sales 
volume-based definition of ``small business,'' an appropriate level 
would be, at a minimum, a total annual sales of $100 million.
    EPA did use SBA's size criteria, which SOCMA stated it prefers, in 
its economic analysis for this final rule. Based on the SBA 
definitions, EPA has concluded that there are no significant impacts on 
small entities (Ref. 57). Regarding SOCMA's second comment, EPA notes 
that SOCMA did not provide its reasoning as to why it considers a 
definition of small business based on a combination of revenue and 
production volume inappropriate, nor did it provide any research or 
justification as to why an appropriate level of annual sales used in 
such a definition should be set at a minimum of $100 million.
    As a more general matter, EPA disagrees with SOCMA's position that 
the SBA small business size standards are the most appropriate to use 
in analyzing the impacts of TSCA section 4 testing rules. The 
Regulatory Flexibility Act (RFA) of 1980, as amended by the Small 
Business Regulatory Enforcement Act (SBREFA) of 1996, requires that 
special consideration be given to small businesses affected by proposed 
Federal regulations. The SBA size standards, which are primarily 
intended to determine whether a business entity is eligible for 
government programs and preferences reserved for small businesses (13 
CFR 121.101), ``seek to ensure that a concern that meets a specific 
size standard is not dominant in its field of operation.'' (13 CFR 
121.102(b)). See section 632(a)(1) of the Small Business Act. Section 
601(3) of RFA establishes as the default definition of ``small 
business'' the definition used in section 3 of the Small Business Act, 
15 U.S.C. 632, under which the SBA establishes small business size 
standards for each industrial sector using an employment threshold that 
entities in that sector may not exceed to be classified as small. (13 
CFR 121.201). RFA recognizes that it may be appropriate at times to use 
an alternate definition of small business for the purpose of analyzing 
potential regulatory impacts. As such, section 601(3) of RFA provides 
that an agency may establish a different definition of small business 
after consultation with the SBA Office of Advocacy and after notice and 
an opportunity for public comment.
    When assessing the potential impacts of test rules on chemical 
manufacturers, EPA believes that a standard based on total annual sales 
may provide a more appropriate means to judge the ability of a chemical 
manufacturing firm to support chemical testing without incurring 
significant costs or burdens. Therefore, EPA is currently determining 
what levels of annual sales would provide the most appropriate size 
cutoff with regard to various segments of the chemical industry usually 
impacted by TSCA section 4(a) test rules. EPA may propose, following 
conclusion of its analysis, that an alternative definition based on 
sales be established in accordance with section 601(3) of the RFA.

IV. Findings

A. What is the Basis for EPA's Final Rule to Test These Chemical 
Substances?

    As indicated in Unit II.B., in order to promulgate a rule under 
TSCA section 4(a) requiring testing of chemical substances or mixtures, 
EPA must make certain findings for those chemical substances or 
mixtures regarding either hazard (TSCA section 4(a)(1)(A)(i)); or 
exposure (TSCA section 4(a)(1)(B)(i)). EPA is requiring testing of the 
chemical substances included in this final rule based on its findings 
under TSCA section 4(a)(1)(B)(i) relating to ``substantial production'' 
and ``substantial human exposure,'' as well as findings under TSCA 
sections 4(a)(1)(B)(ii) and (iii). The chemical substances included in 
this final rule are listed in Sec.  799.5115(j) of the regulatory text 
along with their CAS numbers.
    In EPA's policy for making findings under TSCA section 
4(a)(1)(B)(i) (i.e., the ``B'' policy), ``substantial production'' of a 
chemical substance or mixture is generally interpreted to be aggregate 
production (including import) volume equaling or exceeding one million 
pounds per year (Ref. 55, p. 28746). The general ``B'' policy threshold 
for ``substantial human exposure'' of workers is the exposure of 1,000 
workers annually to a chemical substance or mixture (Ref. 55, p. 
28746). See EPA's ``B'' policy (Ref. 55) for further discussion on how 
EPA generally makes decisions under TSCA section 4(a)(1)(B)(i).
    EPA finds that, under TSCA section 4(a)(1)(B)(i), each of the 34 
chemical substances included in this final rule is produced in 
``substantial quantities'' and there is or may be ``substantial human 
exposure'' to each chemical substance (Ref. 56). In addition, under 
TSCA section 4(a)(1)(B)(ii), EPA believes that there are insufficient 
data and experience to reasonably determine or predict the effects of 
the manufacture, processing, or use of these chemical substances, or of 
any combination of such activities, on human health or the environment. 
In particular, as discussed

[[Page 22424]]

in Unit IV.D., EPA has determined that there are insufficient in vitro 
dermal absorption rate data on these chemicals. EPA also finds that 
testing of the 34 chemical substances is necessary to develop such data 
(TSCA section 4(a)(1)(B)(iii)) (see Unit IV.E.). EPA has not identified 
any ``additional factors'' as discussed in the ``B'' policy (Ref. 55, 
p. 28746) to cause the Agency to use decision making criteria other 
than the general thresholds described in the policy with respect to the 
chemicals included in this final rule.

B. Are These Chemical Substances Produced and/or Imported in 
Substantial Quantities?

    Each of the chemical substances included in this final rule is 
produced and/or imported in an amount equal to or greater than one 
million pounds per year (Ref. 57), based on information gathered 
pursuant to the 2002 TSCA section 8(a) IUR (40 CFR part 710). The IUR 
is the most recently available compilation of TSCA Inventory data, and 
is contained in the TSCA Chemical Update System. EPA believes that 
these annual production volumes are ``substantial'' as that term is 
used with reference to production in TSCA section 4(a)(1)(B)(i) (Ref. 
55).

C. Are a Substantial Number of Workers Exposed to These Chemicals?

    EPA finds that the manufacture, processing, and use of the chemical 
substances included in this action result or may result in exposure to 
a substantial number of workers. These chemical substances are used in 
a wide variety of industrial applications which result in potential 
exposures to workers, as described in the exposure support document for 
this final rule (Ref. 56).
    EPA defines human exposure as the contact with a chemical or agent 
at the visible exterior of a person (i.e., skin and openings into the 
body such as mouth and nostrils) (Ref. 58, p. 22891). Worker exposure 
is the human exposure to a chemical or agent that occurs while a person 
is working. Worker exposure may have various causes, with chemical 
releases being a common cause of exposure. Chemical manufacturing and 
processing plants can release chemicals from pumps as fugitive 
emissions, from reactor and condenser vents as stack emissions, in the 
form of a vapor and/or as a particulate. Diffusion and air currents may 
carry a chemical throughout the plant and workers may breathe air 
containing the chemical, resulting in exposures. Certain human 
activities such as manually transferring a chemical from one container 
to another may also cause exposures.
    Each of the chemicals in this final rule was identified in the NOES 
as having a total worker exposure of 1,000 workers or more (Ref. 56). 
EPA believes that an exposure of 1,000 workers or more to a chemical 
substance is or may be ``substantial'' as that term is used with 
reference to ``human exposure'' in TSCA section 4(a)(1)(B)(i) (Ref. 
55).

D. Do Sufficient Data Exist for These Chemical Substances?

    As discussed in this preamble, dermal absorption rate is an 
important factor in ascertaining the health effects of the 34 chemicals 
in this final rule. EPA has determined that for the 34 chemicals for 
which in vitro dermal absorption rate testing is required under this 
final rule, there is either no dermal absorption rate information 
available or where there is some information, these data are 
insufficient to estimate dermal absorption rate. Therefore, existing 
data are insufficient to reasonably determine or predict the human 
health effects that may result from dermal exposures to the chemical 
substances included in this final rule during the manufacturing, 
processing, or use of the subject chemical substances. This finding is 
based on the review and analysis of relevant data by the ITC (which 
included EPA participation), as described in Unit II.A.

E. Is Testing Necessary for These Chemical Substances?

    EPA believes that the testing of these 34 subject chemical 
substances is necessary to determine if the manufacturing, processing, 
or use of these chemical substances may present an unreasonable risk of 
injury to human health. In particular, the testing required by this 
final rule will provide dermal absorption rate data which OSHA can 
consider together with toxicity data to evaluate the need for skin 
designations which are used to protect against potential health risks 
associated with exposures to these chemicals in the workplace. See Unit 
III.B.3. for a detailed description of this and other data needs that 
will be filled by the testing required by this final rule.

V. Final Rule

A. What Testing is Required by this Action?

    EPA is specifying testing and reporting requirements for the 
chemical substances listed in Table 2 in Sec.  799.5115(j) of the 
regulatory text according to the in vitro dermal absorption rate test 
standard set forth in Sec.  799.5115(h) of the regulatory text.
    The test standard that will be used under this final rule was 
refined as described in Unit III.B. of the proposed rule (Ref. 5). In 
addition, certain modifications which added flexibility to the test 
standard have been made in response to comments submitted to EPA and 
addressed in Unit III.E.2. of this final rule.

B. When Will the Testing Imposed by this Final Rule Begin?

    Once this final rule is effective, which will be 30 days after its 
publication in the Federal Register, the required testing must be 
initiated at a time sufficient to allow the final report to be 
submitted by the deadline indicated in Sec.  799.5115(i) of the 
regulatory text, i.e., 13 months after the effective date of the final 
rule.

C. How Must the Studies Required Under this Test Rule be Conducted?

    Persons required to comply with this final rule must conduct the 
necessary testing in accordance with the testing and reporting 
requirements described in the regulatory text, and with the TSCA Good 
Laboratory Practice Standards (GLPS) (40 CFR part 792). Clarification 
was provided in the test standard concerning how data should be 
reported. The clarification indicates that means and standard 
deviations must be used when reporting the required determinations. 
Although the test standard in the proposed rule would have required 
three separate determinations for each chemical (i.e., one each for Kp, 
10-minute, and 60-minute short-term dermal absorption rates), reporting 
each as a mean and standard deviation was not specified. However, good 
scientific practice would suggest that the determinations be reported 
in this way, and EPA believes that this clarification does not 
substantively change the reporting requirements or their burden and 
costs (Ref. 57).

D. What Substances Will be Tested Under this Final Rule?

    The ``Class 1'' chemical substances listed in Table 2 in Sec.  
799.5115(j) of the regulatory text (i.e., 32 of the 34 chemical 
substances included in this final rule) must be tested at a purity of 
at least 99%. The term Class 1 chemical substance refers to a chemical 
substance having a chemical composition that consists of a single 
chemical species (not including impurities) that can be represented by 
a specific, complete structure diagram. In those instances in which the 
test sponsor(s) believes that a 99% level of purity is unattainable for 
a given chemical, the sponsor may

[[Page 22425]]

request a modification under the procedures described in 40 CFR 790.55.
    For the ``Class 2'' chemical substances listed in Table 2 in Sec.  
799.5115(j) of the regulatory text (i.e., 2 of the 34 chemical 
substances included in this final rule), EPA is requiring that the 
substance to be tested be any representative form of the chemical 
substance.
    In providing a different approach for identifying the substance to 
be tested with regard to Class 2 substances, EPA recognizes two 
characteristics which further distinguish Class 2 from Class 1 chemical 
substances. First, unlike Class 1 substances, knowledge of the 
composition of commercial Class 2 substances can vary in quality and 
specificity from substance to substance. The composition of the 
chemical species which comprise a Class 2 substance may be:

     Well characterized in terms of molecular 
formulae, structural diagrams, and compositional percentages of all 
species present (for example, methyl phenol);
     Less well-characterized, for example, 
characterized only by molecular formulae, nonspecific structural 
diagrams, and/or by incomplete or unknown compositional percentages of 
the species present (for example C12-C14 tert-
alkyl amines); or
     Poorly characterized because all that is known 
is the identity of only some of the chemical species present and their 
percentages of composition, or of only the feedstock and method used to 
manufacture the substance (for example, nut shell liquors of cashews).

    Second, the composition of some Class 2 substances may vary from 
one manufacturer to another, or, for a single manufacturer, from 
production run to production run, because of small variations in 
feedstock, manufacturing methods, or other production variables. A 
``Class 2'' designation most frequently applies to a substance 
consisting of a combination of different chemical species that are 
either structurally similar or related by being formed together when a 
certain chemical reaction or process is carried out on a certain 
chemical feedstock. Small variations in the feedstock or in chemical 
production methods or conditions can account for the types of small 
variations in composition typically allowable within a given Class 2 
Inventory listing. By contrast, a ``Class 1'' designation generally 
applies to a substance which is an individual chemical whose only 
variables are its impurities and byproducts.
    EPA believes that, for purposes of this final rule which would 
require the determination of a Kp and two in vitro short-term dermal 
absorption rates, the testing of any representative form of a subject 
Class 2 substance would be relevant to a determination of whether the 
chemical substance would or would not present an unreasonable risk to 
human health. However, EPA would encourage the selection of 
representative forms of the test substances that meet industry or 
consensus standards, where they exist. In accordance with TSCA GLPS at 
40 CFR part 792, the final study report must include test substance 
identification information, including name, CAS No., strength, purity, 
and composition, or other appropriate characteristics. (See 40 CFR 
792.185).

E. Am I Required to Test Under this Final Rule?

    Under TSCA section 4(a)(1)(B), EPA finds that there are 
insufficient data and experience to reasonably determine or predict 
health effects resulting from the manufacture, processing, or use of 
the chemical substances listed in this rulemaking. As a result, under 
TSCA section 4(b)(3)(B), manufacturers and processors of these 
substances are subject to the final rule with regard to those listed 
chemicals which they manufacture or process.
    1. Am I subject to this final rule? You are subject to this final 
rule and may be required to test if you manufacture (which is defined 
by statute to include import) or process, or intend to manufacture or 
process, one or more chemical substances listed in Table 2 in Sec.  
799.5115(j) of the regulatory text during the time period discussed in 
Unit V.E.2. However, if you do not know or cannot reasonably ascertain 
that you manufacture or process a listed test substance (based on all 
information in your possession or control, as well as all information 
that a reasonable person similarly situated might be expected to 
possess, control, or know, or could obtain without an unreasonable 
burden), you are not subject to the final rule for that listed 
substance.
    2. When will my manufacture or processing (or my intent to do so) 
cause me to be subject to this final rule? You are subject to this 
final rule if you manufacture or process, or intend to manufacture or 
process, a substance listed in Table 2 in Sec.  799.5115(j) of the 
regulatory text at any time from the effective date of the final test 
rule to the end of the test cost reimbursement period.
    The term reimbursement period is defined at 40 CFR 791.3(h) and may 
vary in length for each substance to be tested under a final TSCA 
section 4(a) test rule, depending on what testing is required and when 
testing is completed. (See Unit V.E.4.).
    3. Will I be required to test if I am subject to the final rule? It 
depends on the nature of your activities. All persons who are subject 
to this TSCA section 4(a) test rule, which, unless otherwise noted in 
the regulatory text, incorporates EPA's generic procedures applicable 
to TSCA section 4(a) test rules (contained within 40 CFR part 790), 
fall into one of two groups, designated here as Tier 1 and Tier 2. 
Persons in Tier 1 (those who must initially comply with the final rule) 
must either: Submit to EPA letters of intent to conduct testing, 
conduct this testing, and submit the test data to EPA or apply to and 
obtain from EPA exemptions from testing. Persons in Tier 2 (those who 
do not have to initially comply with the final rule) need not take any 
action unless they are notified by EPA that they are required to do so, 
as described in Unit V.E.3.d. Note that persons in Tier 1 who obtain 
exemptions and persons in Tier 2 are nonetheless subject to providing 
reimbursement to persons who actually conduct the testing, as described 
in Unit V.E.4.
    a. Who is in Tier 1 and Tier 2? All persons subject to this final 
rule are considered to be in Tier 1 unless they fall within Tier 2. The 
following table describes who is in Tier 1 and Tier 2.


[[Page 22426]]



 Table 1.--Persons Subject to the Final Rule: Persons in Tier 1 and Tier
                                    2
------------------------------------------------------------------------
 Tier 1 (Persons initially required to    Tier 2 (Persons not initially
                comply)                        required to comply)
------------------------------------------------------------------------
Persons who manufacture (as defined at   Tier 2A
 TSCA section 3(7)), or intend to        Persons who manufacture (as
 manufacture, a test rule substance who   defined at TSCA section 3(7))
 are not listed under Tier 2              or intend to manufacture a
                                          test rule substance solely as
                                          one or more of the following:
                                         --As a byproduct (as defined at
                                          40 CFR 791.3(c));
                                         --As an impurity (as defined at
                                          40 CFR 790.3);
                                         --As a naturally occurring
                                          substance (as defined at 40
                                          CFR 710.4(b));
                                         --As a non-isolated
                                          intermediate (as defined at 40
                                          CFR 704.3);
                                         --As a component of a Class 2
                                          substance (as described at 40
                                          CFR 720.45(a)(1)(i));
                                         --In amounts of less than 500
                                          kg (1,100 lbs) annually (as
                                          described at 40 CFR
                                          790.42(a)(4)); or
                                         --In small quantities solely
                                          for research and development
                                          (as described at 40 CFR
                                          790.42(a)(5))
                                         Tier 2B
                                         Persons who process (as defined
                                          at TSCA section 3(10)) or
                                          intend to process a test rule
                                          substance (see 40 CFR
                                          790.42(a)(2))
------------------------------------------------------------------------


    b. When is it appropriate for a person required to comply with the 
rule to apply for an exemption rather than to submit a letter of intent 
to conduct testing? You may apply for an exemption if you believe that 
the required testing will be performed by another person (or a 
consortium of persons formed under TSCA section 4(b)(3)(A)). You can 
find procedures relating to exemptions in 40 CFR 790.80 through 790.99, 
and Sec.  799.5115(c)(2), (c)(5), (c)(7), and (c)(11) of the regulatory 
text. In this final rule, EPA will not require the submission of 
equivalence data (i.e., data demonstrating that your substance is 
equivalent to the substance actually being tested) as a condition for 
approval of your exemption. Therefore, 40 CFR 790.82(e)(1) and 40 CFR 
790.85 do not apply to this final test rule.
    c. What will happen if I submit an exemption application? EPA 
believes that requiring the collection of duplicative data is 
unnecessarily burdensome. As a result, if EPA receives a letter of 
intent to test from another source or has received (or expects to 
receive) the test data that are required under this final rule, the 
Agency will conditionally approve your exemption application under 40 
CFR 790.87. The Agency will terminate conditional exemptions if a 
problem occurs with the initiation, conduct, or completion of the 
required testing, or with the submission of the required data to EPA. 
EPA may then require you to submit a letter of intent to test or an 
exemption application. See 40 CFR 790.93 and Sec.  799.5115(c)(10) of 
the regulatory text. Persons who obtain exemptions or receive them 
automatically will nonetheless be subject to providing reimbursement to 
persons who actually conduct the testing, as described in Unit V.E.4.
    d. What are my obligations if I am in Tier 2? If you are in Tier 2, 
you are subject to the final rule and you are responsible for providing 
reimbursement to persons in Tier 1, as described in Unit V.E.4. You are 
considered to have an automatic conditional exemption. You do not need 
to submit a letter of intent to test or an exemption application unless 
you are notified by EPA that you are required to do so.
    If a problem occurs with the initiation, conduct, or completion of 
the required testing, or the submission of the required data to EPA, 
the Agency may require you to submit a letter of intent to test or an 
exemption application. See 40 CFR 790.93 and Sec.  799.5115(c)(10) of 
the regulatory text. In addition, you will need to submit a letter of 
intent to test or an exemption application if:

     No manufacturer in Tier 1 has notified EPA of 
its intent to conduct testing.
     EPA has published a Federal Register document 
directing persons in Tier 2 to submit to EPA letters of intent to 
conduct testing or exemption applications. (See Sec.  799.5115(c)(4), 
(c)(5), (c)(6), and (c)(7) of the regulatory text.)

The Agency will conditionally approve an exemption application under 40 
CFR 790.87, if EPA has received a letter of intent to test or has 
received (or expects to receive) the test data required under this 
final rule.
    e. Subdivision of Tier 2 entities. In the proposed rule that 
preceded this final rule, EPA solicited comment on the issue of whether 
the Agency should prioritize which persons in Tier 2 would be required 
to perform testing, if needed (Ref. 5, p. 31082). Specifically, the 
Agency suggested that it could subdivide Tier 2 entities into:

     Tier 2A. Tier 2 manufacturers, i.e., those who 
manufacture, or intend to manufacture, a test rule substance solely as 
one or more of the following: A byproduct; an impurity; a naturally 
occurring substance; a non-isolated intermediate; a component of a 
Class 2 substance; in amounts less than 1,100 lbs. annually; or in 
small quantities solely for research and development.
     Tier 2B. Tier 2 processors, i.e., those who 
process, or intend to process, a test rule substance (in any form). The 
terms ''process'' and ''processor'' are defined by TSCA section 3(10) 
and (11), respectively.

    After consideration of comments received by the Agency (see Unit 
III.I.3.), EPA has decided that it will subdivide Tier 2 in the 
suggested manner, and the final rule regulatory text is structured to 
reflect this. If the Agency needs testing from persons in Tier 2, EPA 
will seek testing from persons in Tier 2A before proceeding to Tier 2B. 
It is appropriate to require manufacturers in Tier 2A to submit letters 
of intent to test or exemption applications before processors are 
called upon because the Agency believes that testing costs are 
traditionally passed by manufacturers along to processors, enabling 
them to share in the costs of testing (Ref. 74, p. 20654). In addition, 
``[t]here are [typically] so many processors [of a given test rule 
chemical] that it would be difficult to include them all in the 
technical decisions about the tests and in the financial decisions 
about how to allocate the costs'' (Ref. 79, p. 31789).
    f. How did EPA decide who would be in Tier 1 and Tier 2 and who 
would be excluded from the rule? Under 40 CFR 790.2, EPA may establish 
procedures applying to specific test rules that differ from the generic 
procedures governing TSCA section 4 test rules in 40 CFR part 790. For 
the purposes of this final rule, EPA is setting forth certain 
requirements

[[Page 22427]]

that differ from those under 40 CFR part 790.
    In this test rule, EPA has reconfigured the tiers in 40 CFR 790.42. 
EPA has added the following persons to Tier 2: Byproduct manufacturers; 
impurity manufacturers; manufacturers of naturally occurring 
substances; manufacturers of non-isolated intermediates; and 
manufacturers of components of Class 2 substances. The Agency took 
administrative burden and complexity into account in determining who 
was to be in Tier 1 in this rule. EPA believes that those persons in 
Tier 1 who will conduct testing under this final rule will generally be 
large chemical manufacturers who, in the experience of the Agency, have 
traditionally conducted testing or participated in testing consortia 
under previous TSCA section 4(a) test rules.
    The Agency also believes that byproduct manufacturers, impurity 
manufacturers, manufacturers of naturally occurring substances, 
manufacturers of non-isolated intermediates, and manufacturers of 
components of Class 2 substances historically have not themselves 
participated in testing or contributed to the reimbursement of those 
persons who have conducted testing. EPA understands that these 
manufacturers may include persons for whom the marginal transaction 
costs involved in negotiating and administering testing arrangements 
are deemed likely to raise the expense and burden of testing to a level 
that is disproportionate to the additional benefits of including these 
persons in Tier 1. Therefore, EPA does not believe that the likelihood 
of the persons who are being added to Tier 2 actually conducting the 
testing is sufficiently high to justify burdening these persons with 
Tier 1 requirements (e.g., submitting requests for exemptions). 
Nevertheless, these persons, along with all other persons in Tier 2, 
are subject to reimbursement obligations to persons who actually 
conduct the testing, as described in Unit V.E.4.
    TSCA section 4(b)(3)(B) requires all manufacturers and processors 
of a chemical substance to test that chemical substance if EPA has made 
findings for that chemical substance, and therefore issued a TSCA 
section 4(a) test rule requiring testing. However, practicality must be 
a factor in determining who is subject to a particular test rule. Thus, 
persons who do not know or cannot reasonably ascertain that they are 
manufacturing or processing the substances subject to this final rule, 
e.g., manufacturers or processors of the substances as trace 
contaminants who are not aware of these activities, are not subject to 
the final rule. (See Unit V.E.1. and Sec.  799.5115(b)(2) of the 
regulatory text.)
    4. How do the reimbursement procedures work? In the past, persons 
subject to test rules have independently worked out among themselves 
their respective financial contributions to those persons who have 
actually conducted the testing. However, if persons are unable to agree 
privately on reimbursement, they may take advantage of EPA's 
reimbursement procedures at 40 CFR part 791, promulgated under the 
authority of TSCA section 4(c). These procedures include:

     The opportunity for a hearing with the American 
Arbitration Association.
     Publication by EPA of a Federal Register 
document concerning the request for a hearing.
     The appointment of a hearing officer to propose 
an order for fair and equitable reimbursement.

The hearing officer may base his or her proposed order on the 
production volume formula set out at 40 CFR 791.48, but is not 
obligated to do so. Under this final rule, amounts manufactured as 
impurities will be included in production volume (40 CFR 791.48(b)), 
subject to the discretion of the hearing officer (40 CFR 791.40(a)). 
The hearing officer's proposed order may become the Agency's final 
order, which is reviewable in Federal court (40 CFR 791.60).

F. What are the Reporting Requirements Under this Final Rule?

    A final report must be submitted for each chemical 13 months after 
the effective date of the final rule, i.e., by the deadline indicated 
in Sec.  799.5115(i) of the regulatory text. Although EPA originally 
proposed a deadline of 9 months after the effective date, EPA extended 
the reporting deadline to 13 months after the effective date in 
response to public comments. (See Unit III.E.2.f.). EPA is not 
requiring the submission of interim progress reports for the in vitro 
dermal absorption rate testing required in this final rule. For the 
short-term studies required by this final rule, interim progress 
reports would likely yield little useful information. Furthermore, by 
not requiring interim progress reports for these short-term studies, 
the overall burden of the final rule will be somewhat reduced.

G. What Would I Need to Do if I Cannot Complete the Testing?

    A company that submits a letter of intent to test under this final 
rule and that subsequently anticipates difficulties in completing the 
testing by the deadline may submit a request to the Agency to modify 
the test schedule, pursuant to 40 CFR 790.55. EPA will determine 
whether modification of the test schedule is appropriate, and may first 
seek public comment on the modification.

H. Will There be Sufficient Test Facilities and Personnel to Undertake 
the Testing in this Test Rule?

    Various surveys of the availability of test facilities and 
personnel to handle the additional demand for testing services created 
by TSCA section 4(a) test rules indicate that available test facilities 
and personnel will adequately accommodate the testing specified in this 
final rule (Refs. 46, 52, and 53) (see also Unit III.G.).

I. Might EPA Seek Further Testing of the Chemicals in this Final Rule?

    If EPA determines that it needs additional data regarding any of 
the chemical substances included in this final rule, the Agency might 
seek further health and/or environmental effects testing for these 
chemical substances. Should the Agency decide to seek such additional 
testing, EPA would initiate a separate action under TSCA section 4 for 
that purpose.

VI. Export Notification

    Any person who exports, or who intends to export, one of the 
chemical substances contained in this final rule in any form is subject 
to the export notification requirements in TSCA section 12(b)(1) and at 
40 CFR part 707, subpart D. However, export notification is generally 
not required for articles, as provided by 40 CFR 707.60(b).

VII. Decision to Terminate Rulemaking

    EPA is withdrawing the in vitro dermal absorption rate testing 
proposed on June 9, 1999 (64 FR 31074) for 13 chemicals: Ethyl ether, 
isobutyl alcohol, sec-butyl alcohol, o-dichlorobenzene, p-nitrotoluene, 
beta-chloroprene, n-amyl acetate, N-isopropylaniline, o-dinitrobenzene, 
ethyl bromide, o-chlorotoluene, disulfiram, and N,N-dimethylaniline. 
The rationale for the decision to withdraw this proposed testing is 
presented in this unit.

A. Ethyl Ether

    DEPA commented that ethyl ether (CAS No. 60-29-7) should be removed 
from the rule, in part, because dermal

[[Page 22428]]

absorption rate data had previously been developed and because the high 
volatility of ethyl ether would not allow a dermal absorption rate to 
be adequately determined under the proposed standard (Ref. 21).
    EPA and OSHA have reviewed the dermal absorption rate study by 
Blank et al., 1967 (Journal of Investigative Dermatology. 49:582-589), 
submitted by DEPA as an attachment to its comments (Ref. 21). The study 
measured a Kp for an aqueous solution of ethyl ether through a human 
abdominal epidermal membrane using an in vitro static diffusion cell. 
Barrier function was maintained as verified by measuring penetration of 
tritiated water. Most other experimental parameters conformed with the 
standard proposed by EPA for determining an in vitro dermal absorption 
rate. A sensitive gas chromatographic method was used to analyze the 
receptor fluid in place of radiolabeled compound. It is unclear whether 
absorption was determined under occluded or unoccluded conditions, but 
the Kp values are close to theoretical calculations, indicating that 
ethyl ether evaporation likely did not confound absorption measurements 
under these experimental conditions. Skin penetration of the neat 
liquid was not reported, but EPA and OSHA believe this can be estimated 
using the aqueous Kp value and data on water solubility and liquid 
density. Therefore, EPA and OSHA believe that this study provides 
sufficient data for an adequate determination of the dermal absorption 
rate information sought in this rulemaking and testing of ethyl ether 
is not required at this time (Ref. 62).

B. Isobutyl Alcohol and Sec-Butyl Alcohol

    ACC, in its comment proposing a category approach when testing 
chemical substances to determine in vitro dermal absorption rates, 
noted that in its suggested aliphatic alcohol category, three of the 
four possible isomers for butyl alcohol were included in the proposed 
rule (Ref. 15). ACC stated that given their same molecular weight and 
functionality, and taking into consideration the likelihood of there 
being existing dermal absorption rate data for other three-, four-, and 
five-carbon alcohols, evaluating the three isomers using a structure 
activity relationship (SAR) approach would appear reasonable, in lieu 
of testing three chemicals under this rule.
    The three butyl alcohols referred to by ACC are isobutyl alcohol 
(CAS No. 78-83-1), sec-butyl alcohol (CAS No. 78-92-2), and tert-butyl 
alcohol (CAS No. 75-65-0). The first two were included in the proposed 
rule. The third substance, tert-butyl alcohol was cited in the proposed 
rule (Ref. 5) as a chemical substance that was removed from the test 
list as a result of a 1998 study. The fourth butyl alcohol, not 
included in the proposed test rule, is n-butyl alcohol (CAS No. 71-36-
3) which the ITC found to have sufficient dermal absorption rate data.
    EPA agrees with ACC that sufficient data on in vitro dermal 
absorption rates have been generated on three, four, and five carbon 
aliphatic alcohols to adequately predict Kps for isobutyl alcohol and 
sec-butyl alcohol (Ref. 62). In vitro dermal absorption rates and Kps 
using human skin have already been measured for a series of homologous 
two [ethanol], three [propanol], four [n-butanol], and five [pentanol] 
carbon aliphatic alcohols (Ref. 65). This provides adequate structure 
activity information to predict the dermal absorption rates for the 
closely related branched chain alcohols, isobutyl alcohol and sec-butyl 
alcohol, with reasonable accuracy. Therefore, EPA is not requiring the 
testing of isobutyl alcohol and sec-butyl alcohol under this final 
rule.

C. o-Dichlorobenzene

    The Chlorobenzene Producers Association cited two documents to 
support its position that testing of o-dichlorobenzene (CAS No. 95-50-
1) is unnecessary (Ref. 31). The Association cited EPA's Dermal 
Exposure Assessment: Principles and Applications (Ref. 42), which 
described a calculated Kp for o-dichlorobenzene. The Association also 
noted that a study conducted at the North Carolina State University at 
Raleigh entitled Percutaneous Absorption of Volatile Compounds (Ref. 
50) analyzed the relative absorption and penetration of o-
dichlorobenzene on the skin surface in the context of evaluating 
volatile organic compounds.
    The Kp value for o-dichlorobenzene cited in the 1992 EPA Report on 
dermal exposure assessment is estimated from empirical models rather 
than experimental data and, therefore, does not meet OSHA needs. 
However, the data developed for o-dichlorobenzene in the context of 
evaluating percutaneous absorption of volatile organic compounds does 
provide a measure of the dermal absorption rate of o-dichlorobenzene. 
Therefore, testing of o-dichlorobenzene is not required in this final 
rule.

D. p-Nitrotoluene

    First Chemical Corporation provided EPA with biological monitoring 
information (Ref. 17a.), toxicity studies (Ref. 17b.), and specific 
information on the numbers of workers exposed to p-nitrotoluene (CAS 
No. 99-99-0) (Ref. 17). First Chemical Corporation concluded from the 
submitted information that p-nitrotoluene does not present a 
significant hazard from dermal contact and proposed that this chemical 
be removed from the test list. One study (Ref. 17a.) discussed 
biological monitoring in workers but did not measure dermal absorption. 
An acute toxicity study with short-term dermal administration to 
experimental animals was negative (Ref. 17b.). This study also did not 
attempt to measure dermal absorption, and, therefore is not adequate to 
eliminate the testing requirement. A submission under section 8(d) of 
TSCA ``found no evidence of skin absorption when a dermal dose of 1.0 
g/kg was applied to rabbits'' (Ref. 17) but further review by EPA finds 
no mention of the methodology or data that support this statement in 
the submission. EPA does not consider the data cited by First Chemical 
Corporation to be sufficient to determine a dermal absorption rate for 
p-nitrotoluene (Ref. 62).
    First Chemical Corporation also submitted data relevant to EPA's 
finding of substantial human exposure. First Chemical Corporation is 
the only domestic manufacturer of p-nitrotoluene and accounts for the 
vast majority of the total quantity on the U.S. market. The company 
provided information on handling procedures, onsite operations, and a 
summary of the number of workers with potential exposure to the 
chemical. This summary was based on a survey of onsite operations and 
inquiries to each offsite company known to handle p-nitrotoluene. EPA 
has reviewed these data and agrees with First Chemical Corporation that 
the number of workers exposed to p-nitrotoluene at its facilities and 
those of its customers (processors) do not meet the general worker 
threshold for substantial human exposure that EPA has established to 
require testing under TSCA section 4(a)(1)(B). EPA has also reviewed 
the information submitted in response to the TSCA section 8(a) PAIR for 
p-nitrotoluene (Ref. 8). PAIR information for 1994 revealed that 
another company in the p-nitrotoluene market did not use p-nitrotoluene 
in its processes, sell it to its customers, or report any worker 
exposure, thus making the number of exposed workers reported by First 
Chemical Corp. the total of the reported worker exposures in the United 
States. Therefore, EPA is

[[Page 22429]]

not requiring testing of p-nitrotoluene under this final rule.

E. beta-Chloroprene

    DuPont Dow Elastomers (DDE) provided EPA with specific information 
on production and worker exposure to beta-chloroprene (CAS No. 126-99-
8) during production and use (Ref. 24). According to DDE, domestic 
production of beta-chloroprene occurs only at DDE's facility in 
LaPlace, Louisiana. DDE also states that no beta-chloroprene is 
imported. DDE acknowledges that beta-chloroprene is manufactured in 
quantities in excess of one million pounds per year which satisfies the 
``substantial production'' TSCA section 4(a)(1)(B) finding. However, 
the company maintains that the number of workers exposed to beta-
chloroprene does not meet the general ``substantial human exposure'' 
TSCA section 4(a)(1)(B) finding.
    According to DDE, more than 90% of beta-chloroprene produced 
annually is used for the production of dry polychloroprene. Most of the 
remaining beta-choloroprene is used to produce polychloroprene latex, a 
colloidal suspension of polychloroprene in water. A small portion is 
used to manufacture a comonomer, subsequently incorporated in 
polychloroprene polymerization. DDE states that polymer manufacture is 
the only commercial use of beta-chloroprene. From its sole beta-
chloroprene production facility in Louisiana, DDE produces beta-
chloroprene monomer to supply its polychloroprene manufacturing 
operations. DDE, the only domestic producer of beta-chloroprene or 
polychloroprene, handles beta-chloroprene at only two of its facilities 
and the total number of DDE employees at these sites is approximately 
500. DDE states that the actual number of the workers exposed via the 
dermal route is significantly less than the total number of DDE 
employees at the two facilities that manufacture or handle beta-
chloroprene. DDE has determined that the total number of workers 
potentially exposed to beta-chloroprene vapor is less than 200. Due to 
the nature of the beta-chloroprene and polychloroprene manufacturing 
processes, the number of workers with potential exposure to liquid 
beta-chloroprene is apparently significantly less than those 
potentially exposed to beta-chloroprene vapor.
    EPA has reviewed the production and worker exposure information 
submitted by DDE and concurs with DDE in its assessment of the 
potential number of workers exposed to beta-chloroprene. Because the 
potential number of workers exposed to beta-chloroprene does not appear 
to meet the threshold that EPA generally relies upon in making the TSCA 
section 4(a)(1)(B) ``substantial human exposure'' finding on the basis 
of worker exposure, testing of beta-chloroprene is not required under 
this final rule.

F. n-Amyl acetate

    EPA and OSHA have reviewed a dermal absorption study for n-amyl 
acetate (CAS No. 628-63-7) submitted by Union Carbide Corporation (Ref. 
47). A Kp and 6-24 hours dermal absorption rates for n-amyl acetate 
were determined. Absorption data were also collected at earlier time 
points of 10 minutes and 1 hour. The method used an in vitro static 
diffusion cell technique with human cadaver skin and was similar, but 
not identical, to the test standard for the study required in this 
final rule. The test substance was a mixed isomer of primary amyl 
acetate applied neat (65% n-amyl acetate) rather than as a pure 
compound. A sensitive (non-radiolabeled) gas chromatographic technique 
specific to n-amyl acetate was used as a detection method. The 
anatomical region of the skin and membrane thickness were not stated, 
although variability in the results and the method of epidermal 
membrane preparation were found to be acceptable. The receptor fluid 
was ethanol in water instead of the PEG solution required in the test 
standard for this final rule; however, it is unlikely that this 
influenced the results of the study because ethanol in water, as stated 
previously in Unit III.E.2.o.vii., is generally a suitable receptor 
fluid. This is the case despite the fact that under this final rule EPA 
is requiring the use of a PEG solution as the receptor fluid for all 
hydrophobic chemicals for purposes of consistency. Therefore, EPA and 
OSHA believe that this study provides sufficient data for an adequate 
determination of dermal absorption rate and further testing of n-amyl 
acetate is not required under this final rule (Ref. 64).

G. N-Isopropylaniline

    Monsanto Company provided EPA with specific information on 
production and worker exposure to N-isopropylaniline (CAS No. 768-52-5) 
during production and use (Ref. 16). Monsanto Company stated that N-
isopropylaniline is an intermediate in the production of the pesticide 
propachlor, the active ingredient in Ramrod branded herbicides, and is 
produced and consumed at the Monsanto plant in Muscatine, Iowa. No N-
isopropylaniline is sold or used domestically for any other purpose. 
Propachlor, which was introduced on the market in 1965, is nearing the 
end of its commercial life cycle and production of N-isopropylaniline 
has fallen accordingly. Thus, it is anticipated that N-isopropylaniline 
will be produced in amounts far less than the Agency's general 
``substantial production'' threshold of one million pounds per year.
    Monsanto Company also provided EPA with a detailed description of 
the number of workers exposed to N-isopropylaniline during production 
and use. N-isopropylaniline is produced and consumed in enclosed 
systems. Monsanto Company projected a maximum of 35 workers are 
potentially exposed to N-isopropylaniline.
    EPA has reviewed the production and worker exposure information 
submitted by Monsanto Company for N-isopropylaniline. EPA has 
confirmed, via 1998 and 2002 IUR data (see 40 CFR part 710), that 
manufacture (including import) of N-isopropylaniline is below the one 
million pounds per year threshold which EPA generally relies upon as 
``substantial production'' under TSCA section 4(a)(1)(B). In addition, 
the potential number of workers exposed to N-isopropylaniline does not 
appear to meet the ``substantial human exposure'' threshold of exposure 
equal to or greater than 1,000 workers which EPA generally relies upon 
in making the TSCA section 4(a)(1)(B) ``substantial human exposure'' 
finding on the basis of worker exposure. As a result, testing of N-
isopropylaniline is not required under this final rule.

H. o-Dinitrobenzene

    EPA received no comments in response to its proposal to require 
that o-dinitrobenzene (CAS No. 528-29-0) be tested to determine an in 
vitro dermal absorption rate. In developing a finding for the final 
rule of ``substantial production'' under TSCA section 4(a)(1)(B) for 
this chemical, EPA found that according to 1998 IUR data (see 40 CFR 
part 710), o-dinitrobenzene is no longer produced or imported in 
amounts equal to or greater than one million pounds per year. The 1998 
IUR data became available after the publication of the proposed rule, 
which made a finding for substantial production based on 1994 IUR data. 
Also, there were no 2002 IUR data reported for o-dinitrobenzene. 
Because the 1998 IUR data and the lack of 2002 IUR data do not support 
a finding of substantial production as required under TSCA section 
4(a)(1)(B)(i), testing of o-dinitrobenzene to determine an in vitro 
absorption rate is not required at this time.

[[Page 22430]]

I. Ethyl Bromide, o-Chlorotoluene, Disulfiram, and N,N-Dimethylaniline

    In developing findings for the final rule of ``substantial 
production'' under TSCA section 4(a)(1)(B) for ethyl bromide (CAS. No. 
74-96-4), o-chlorotoluene (CAS No. 95-49-8), disulfiram (CAS No. 97-77-
8), and N,N-dimethylaniline (CAS No. 121-69-7), EPA found that 
according to 2002 IUR data (see 40 CFR part 710), these four chemical 
substances are no longer manufactured or imported in amounts equal to 
or greater than one million pounds per year. Because the 2002 IUR data 
show manufacture (including import) below the one million pounds per 
year threshold which EPA generally relies upon as ``substantial 
production'' under TSCA section 4(a)(1)(B)(i), testing of ethyl 
bromide, o-chlorotoluene, disulfiram, and N,N-dimethylaniline to 
determine in vitro dermal absorption rates is not required at this 
time.

VIII. Economic Impacts

    EPA has prepared an economic assessment entitled Economic Impact 
Analysis and Small Entity Impact Analysis of the TSCA Section 4(a) Test 
Rule for 34 Chemicals Targeted for In Vitro Dermal Absorption Rate 
Testing (Ref. 57), a copy of which has been placed in the official 
public docket. This economic assessment evaluates the potential for 
significant economic impacts as a result of the testing that would be 
required by this final rule. The total cost of providing test data on 
the 34 chemicals that were evaluated in this economic analysis is 
estimated to be a total of $1.16 million for all 34 chemicals, or 
$33,987 per chemical (Ref. 57).
    While legally subject to this test rule, Tier 2 manufacturers and 
all processors of a subject chemical would only be required to comply 
with the requirements of the final rule if they are directed to do so 
by EPA as described in Sec.  799.5115(c)(5), (c)(7) and (c)(10) of the 
regulatory text. EPA would require Tier 2 manufacturers or processors 
to test only if no Tier 1 manufacturer has submitted a letter of its 
intent to conduct testing, or if, under 40 CFR 790.93, a problem occurs 
with the initiation, conduct, or completion of the required testing, or 
the submission of the required data to EPA. Because EPA has identified 
at least one manufacturer in Tier 1 for each subject chemical, the 
Agency expects that, for each chemical in this final rule, at least one 
such person will submit a letter of intent to conduct the required 
testing and that person will conduct such testing and will submit the 
test data to EPA. EPA believes, therefore, that there will not be any 
costs to Tier 2 manufacturers or processors for conducting the testing 
required by the final rule. In addition, as explained in Unit III.J., 
EPA is not aware of any circumstances in which Tier 1 entities have 
sought reimbursement from Tier 2 entities either through private 
agreements or by soliciting the involvement of the Agency under the 
reimbursement regulations at 40 CFR part 791. Given this consistent 
experience with previous test rules, EPA does not believe that there 
will be any administrative, negotiation, or any other costs associated 
with seeking reimbursement from Tier 2 companies.
    To evaluate the potential for an adverse economic impact of testing 
on manufacturers of the chemical substances in this final rule, EPA 
employed a screening approach that compares the annual revenues from 
the sale of a chemical to the annualized testing costs for that 
chemical and expresses the testing costs as a percent of revenues 
generated from each chemical. Annualized testing costs divide testing 
expenditures into an equivalent, constant yearly expenditure over a 
longer period of time. To calculate the percent price impact, testing 
costs (including laboratory and administrative expenditures) are 
annualized over 15 years using a 7% discount rate. Annualized testing 
costs are then divided by the estimated annual revenue of the chemical 
to derive the cost-to-sales ratio.
    EPA estimates the annualized cost of testing the 34 chemicals 
evaluated in the economic analysis to be $3,732 per chemical or a total 
annualized cost of $126,888 for all 34 chemicals (34 x $3,732) (Ref. 
57). In addition, the TSCA section 12(b) export notification that is 
required for the first export to a particular country of a chemical 
subject to the final rule, is estimated to be $61.31 for the first time 
that an exporter must comply with TSCA section 12(b) export 
notification requirements, and $18.07 for each subsequent export 
notification submitted by an exporter (Ref. 57). The Agency's estimated 
total costs of testing (including both laboratory and administrative 
costs), annualized testing costs, price impacts, and public reporting 
burden hours for this final rule are presented in the economic impact 
analysis (Ref. 57).
    Price data were available for 26 of the 34 chemicals, with an 
average cost of $.88 per pound for those 26 chemicals. The price impact 
of the test costs is a function of the chemical's price per pound and 
the production volume. For 21 of the 26 chemicals (80.8%) for which 
price data were available, the price impact is less than 1.0% when the 
production volume for each chemical is assumed to be one million 
pounds, which is the threshold for substantial production. The average 
test cost impact for all 26 chemicals with price data was 0.68%. This 
means that the testing costs represent, on average, 0.68% of revenues 
generated from each chemical. The actual impacts are likely to be 
lower, however, because all of the subject chemicals are produced in 
volumes of at least one million pounds per year. With a price impact of 
less than 1.0%, EPA concludes that for these 21 chemicals the potential 
for adverse economic impacts is low.
    For five of the twenty-six chemicals (19.2%) with price data, the 
price impact is in excess of 1.0%. The average price impact for these 
five chemicals is 1.96% and the maximum is 3.7%. Again, these impacts 
occur when the production volumes are assumed to be one million pounds. 
The actual impacts decline in direct proportion to a chemical's actual 
production volume above one million pounds. Thus, if the actual 
production volume is two million pounds, the impact is reduced by 50%. 
The Agency verified production volumes for these five chemicals based 
on the 2002 reports to the TSCA Chemical Update System Database, and 
has found that the actual production volume in each case exceeds 10 
million pounds per year. Therefore, the Agency believes that the impact 
for all five of these chemicals is below 1.0%.
    The Agency computed ``critical prices'' for the remaining eight 
chemicals for which price data were not available. The ``critical 
price'' is the price per pound below which there would be an impact of 
1.0% or greater. Assuming a minimum production volume of one million 
pounds per year and annualized testing costs of $3,732 per chemical, 
the critical price is $0.37 per pound. Below that price, the testing 
costs would represent more than 1.0% of the revenues from the chemical 
at a one million pound production volume level. The average price for 
the 26 chemicals with actual price data available is $0.88 per pound. 
Thus, the critical price is substantially below this average. While it 
cannot be shown conclusively that the price impacts will be less than 
or greater than 1.0% of the sales for these chemicals, the Agency 
believes that adverse impacts are unlikely, given that both the 
chemicals' prices would have to be below $.37 per pound, and the 
production volume would have to meet the worst-case assumption of one 
million pounds per year.

[[Page 22431]]

    On the basis of these calculations, EPA believes that the required 
chemical testing presents a low potential for adverse economic impact 
for the majority of the chemicals subject to the final rule. Because 
the subject chemical substances have relatively large production 
volumes, the annualized costs of testing, expressed as a percentage of 
annual revenues, are very small for most chemicals. There are, however, 
eight chemicals for which it cannot conclusively be shown that the 
price impact will be below 1.0% of the revenue for these chemicals. For 
these eight chemicals, companies may choose to use revenue sources 
other than profits from the individual chemicals to pay for testing. To 
account for this, the Agency also compared the costs of compliance to 
company sales data. These calculations were made as part of the 
Agency's small entity impact analysis (Ref. 57), conducted in 
accordance with the requirements of the Regulatory Flexibility Act, as 
amended by the Small Business Regulatory Enforcement Fairness Act. 
These results are presented in Unit X.B.

IX. Materials in the Docket

    An official docket was established under docket ID number OPPT-
2003-0006. The official public docket includes information considered 
by EPA in developing this final rule, such as the documents 
specifically referenced in this action, any public comments received, 
and other information related to this action. In addition, interested 
parties should consult documents that are referenced in the documents 
that EPA has placed in the docket, regardless of whether these 
referenced documents are physically located in the docket. For 
assistance in locating documents that are referenced in documents that 
EPA has placed in the docket, but that are not physically located in 
the docket, please consult one of the technical persons listed under 
FOR FURTHER INFORMATION CONTACT. The official public docket is 
available for review as specified in ADDRESSES. The following is a 
listing of the documents referenced in this preamble that have been 
placed in the official docket for this final rule:

A. Supporting Documentation

    1. U.S. Census Bureau. Bridge between NAICS and SIC. 1997 Economic 
Census. Core Business Statistics Series. Issued June 2000.
    2. United States Environmental Protection Agency (USEPA). 
Laboratory Cost Estimate for In Vitro Dermal Absorption Rate Testing--
Short-term Absorption Rate. Prepared by Economic and Policy Analysis 
Branch (EPAB), Economics, Exposure and Technology Division (EETD), 
OPPT. February 20, 2003.
    3. USEPA. Laboratory Cost Estimate for In Vitro Dermal Absorption 
Rate Testing--Long-term Absorption Rate. Prepared by EPAB, EETD, OPPT. 
March 26, 2003.
    4. Background information listed in Sec.  799.5115(h)(8) of the 
regulatory text:
    a. Bronaugh, R.L., Stewart, R.F., and Simon, M. Methods for in 
vitro Percutaneous Absorption Studies VII: Use of Excised Human Skin. 
Journal of Pharmaceutical Sciences. 75:1094-1097. 1986.
    b. Bronaugh, R.L. and Stewart, R.F. Methods for in vitro 
Percutaneous Absorption Studies IV: The Flow-Through Diffusion Cell. 
Journal of Pharmaceutical Sciences. 74:64-67. 1985.
    c. Bronaugh, R.L., Stewart, R.F., and Storm, J.E. Extent of 
Cutaneous Metabolism During Percutaneous Absorption of Xenobiotics. 
Toxicology and Applied Pharmacology. 99:534-543. 1989.
    d. Walker, J.D., Whittaker, C. and McDougal, J.N. Role of the TSCA 
Interagency Testing Committee in Meeting the U.S. Government Data 
Needs: Designating Chemicals for Percutaneous Absorption Rate Testing. 
Dermatotoxicology. F. Marzulli and H. Maibach, Eds. Taylor & Francis, 
Washington, DC. pp. 371-381. 1996.
    e. Bronaugh, R.L., and Collier, S.W. Protocol for In Vitro 
Percutaneous Absorption Studies. In Vitro Percutaneous Absorption: 
Principles, Fundamentals, and Applications. R.L. Bronaugh and H.I. 
Maibach, Eds. CRC Press, Boca Raton, FL. pp. 237-241. 1991.

B. References

    1. Interagency Testing Committee (ITC). Thirty-First Report of the 
TSCA Interagency Testing Committee to the Administrator; Receipt of 
Report, Request for Comments, Opportunity to Initiate Negotiations for 
TSCA Section 4 Testing Consent Agreements. Federal Register (58 FR 
26898, May 5, 1993) (FRL-4583-4).
    2. ITC. Thirty-Second Report of the TSCA Interagency Testing 
Committee to the Administrator; Receipt of Report, Request for 
Comments, Notice of Opportunity to Initiate Negotiations for TSCA 
section 4 Testing Consent Agreements. Federal Register (58 FR 38490, 
July 16, 1993) (FRL-4630-2).
    3. ITC. Thirty-Fourth Report of the TSCA Interagency Testing 
Committee to the Administrator; Receipt of Report and Request for 
Comments. Federal Register (59 FR 35720, July 13, 1994) (FRL-4870-4).
    4. ITC. Thirty-Fifth Report of the TSCA Interagency Testing 
Committee to the Administrator; Receipt of Report, Request for 
Comments, Solicitation of Interested Parties in Developing Testing 
Consent Agreement. Federal Register (59 FR 67596, December 29, 1994) 
(FRL-4923-2).
    5. USEPA. Proposed Test Rule for In Vitro Dermal Absorption Rate 
Testing of Certain Chemicals of Interest to Occupational Safety and 
Health Administration. Federal Register (64 FR 31074, June 9, 1999) 
(FRL-5760-3).
    6. USEPA. Preliminary Assessment Information and Health and Safety 
Data Reporting; Addition of Chemicals. (TSCA Sections 8(a) and 8(d) 
Final Rules for Chemicals contained in the ITC's 31\st\ Report to the 
EPA Administrator). Federal Register (58 FR 68311, December 27, 1993) 
(FRL-4644-1).
    7. USEPA. Preliminary Assessment Information and Health and Safety 
Data Reporting; Addition of Chemicals. (TSCA sections 8(a) and 8(d) 
Final Rules for Chemicals contained in the ITC's 32\nd\ Report to the 
EPA Administrator). Federal Register (59 FR 5956, February 9, 1994) 
(FRL-4745-5).
    8. USEPA. Preliminary Assessment Information and Health and Safety 
Data Reporting; Addition of Chemicals. (TSCA Sections 8(a) and 8(d) 
Final Rules for Chemicals contained in the ITC's 35\th\ Report to the 
EPA Administrator). Federal Register (60 FR 34879, July 5, 1995) (FRL-
4954-9).
    9. USEPA. Thirty-Sixth Report of the TSCA Interagency Testing 
Committee to the Administrator; Receipt of Report, Request for 
Comments, Solicitation of Use and Exposure Data. Federal Register (60 
FR 42982, August 17, 1995) (FRL-4965-6).
    10. USEPA. Request for Proposals for Enforceable Consent 
Agreements; Dermal Absorption Rate Testing of Eighty OSHA Chemicals; 
Solicitation of Interested Parties; Text of Test Protocol. Federal 
Register (61 FR 14773, April 3, 1996) (FRL-5359-3).
    11. ARCO Chemical Company. Proposal to conduct in vivo dermal 
absorption rate testing for tert-butyl alcohol under an enforceable 
consent agreement (ECA). Letter from Joan McCuen to Charles M. Auer, 
OPPT, USEPA. June 26, 1996.
    12. ARCO Chemical Company. A letter from Joan McCuen to Keith 
Cronin, OPPT, USEPA transmitting a dermal absorption rate study (Ref. 
12a.). March 23, 1998.
    12a. Huntington Life Sciences Ltd., Suffolk, England. [14C]-t-Butyl 
Alcohol:

[[Page 22432]]

Topical Application: Dermal Absorption Study in the Male Rat; Final 
Report. Prepared for ARCO Chemical Company. January 7, 1998.
    13. Bronaugh, R.L. and Collier, S.W. Protocol for in vitro 
Percutaneous Absorption Studies. In Vitro Percutaneous Absorption: 
Principles, Fundamentals, and Applications. R.L. Bronaugh and H.I. 
Maibach, Eds. CRC Press, Boca Raton, FL. Chapter 19, pp. 237-241. 1991.
    14. Chemical Manufacturers Association (CMA). Comments on ITC 
proposal for dermal penetration testing and protocol (Ref. 14a.) 
proposed by CMA. Letter from Sarah Doelp to Charles M. Auer, USEPA. 
October 21, 1994.
    14a. CMA, Existing Chemicals Testing Task Group. Proposed Protocol 
for In Vitro Percutaneous Absorption Studies. October 4, 1994.
    15. ACC. Comments on EPA's TSCA section 4(a)(1)(B) Proposed Test 
Rule for In Vitro Dermal Absorption Rate Testing of Certain Chemicals 
of Interest to OSHA submitted to the TSCA Public Docket Office, USEPA. 
August 10, 1999.
    16. Monsanto Company. Comments on EPA's TSCA section 4(a)(1)(B) 
Proposed Test Rule for In Vitro Dermal Absorption Rate Testing of 
Certain Chemicals of Interest to OSHA submitted to the TSCA Public 
Docket Office, USEPA. July 19, 1999.
    17. First Chemical Company. Comments on EPA's TSCA section 
4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption Rate 
Testing of Certain Chemicals of Interest to OSHA submitted to the TSCA 
Public Docket Office, USEPA. August 4, 1999.
    17a. Linch, A.L. Biological monitoring for industrial exposure to 
cyanogenic aromatic nitro and amino compounds. American Industrial 
Hygiene Association Journal. 35:426-432. 1974.
    17b. Kinkead, E.R., MacEwen, J.D., Haun, C.C., Vernot, E.H., and 
Dacre, J.C. Toxic hazards evaluation of five atmospheric pollutants 
from Army ammunition plants. Prepared by University of California, 
Irvine for Aerospace Medical Research Laboratory, Wright-Patterson Air 
Force Base, OH. Report number AMRL-TR-77-25. June 1977.
    18. American Forest & Paper Association. Comments on EPA's TSCA 
section 4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption 
Rate Testing of Certain Chemicals of Interest to OSHA submitted to the 
TSCA Public Docket Office, USEPA. August 9, 1999.
    19. American Petroleum Institute. Comments on EPA's TSCA section 
4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption Rate 
Testing of Certain Chemicals of Interest to OSHA submitted to the TSCA 
Public Docket Office, USEPA. August 9, 1999.
    20. Biphenyl Work Group, Washington, DC. Comments on EPA's TSCA 
section 4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption 
Rate Testing of Certain Chemicals of Interest to OSHA submitted to the 
TSCA Public Docket Office, USEPA. August 6, 1999.
    21. Diethyl Ether Producers Association, Inc. Comments on EPA's 
TSCA section 4(a)(1)(B) Proposed Test Rule for In Vitro Dermal 
Absorption Rate Testing of Certain Chemicals of Interest to OSHA 
submitted to the TSCA Public Docket Office, USEPA. August 9, 1999.
    22. Synthetic Organic Chemical Manufacturers Association, Inc. 
Comments on EPA's TSCA section 4(a)(1)(B) Proposed Test Rule for In 
Vitro Dermal Absorption Rate Testing of Certain Chemicals of Interest 
to OSHA submitted to the TSCA Public Docket Office, USEPA. August 9, 
1999.
    23. Acetonitrile Task Force. Comments on EPA's TSCA section 
4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption Rate 
Testing of Certain Chemicals of Interest to OSHA submitted to the TSCA 
Public Docket Office, USEPA. August 9, 1999.
    24. DuPont Dow Elastomers. Comments on EPA's TSCA section 
4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption Rate 
Testing of Certain Chemicals of Interest to OSHA submitted to the TSCA 
Public Docket Office, USEPA. August 9, 1999.
    25. Fragranced Products Information Network. Comments on EPA's TSCA 
section 4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption 
Rate Testing of Certain Chemicals of Interest to OSHA submitted to the 
TSCA Public Docket Office, USEPA. July 6, 1999.
    26. Association of Veterinarians for Animal Rights. Comments on 
EPA's TSCA section 4(a)(1)(B) Proposed Test Rule for In Vitro Dermal 
Absorption Rate Testing of Certain Chemicals of Interest to OSHA 
submitted to the TSCA Public Docket Office, USEPA. July 17, 1999.
    27. People for the Ethical Treatment of Animals. Comments on EPA's 
TSCA section 4(a)(1)(B) Proposed Test Rule for In Vitro Dermal 
Absorption Rate Testing of Certain Chemicals of Interest to OSHA 
submitted to the TSCA Public Docket Office, USEPA. July 30, 1999.
    28. Animal Protection Institute, Midwest Regional Office. Comments 
on EPA's TSCA section 4(a)(1)(B) Proposed Test Rule for In Vitro Dermal 
Absorption Rate Testing of Certain Chemicals of Interest to OSHA 
submitted to the TSCA Public Docket Office, USEPA. August 4, 1999.
    29. Humane Society of the United States. Comments on EPA's TSCA 
section 4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption 
Rate Testing of Certain Chemicals of Interest to OSHA submitted to the 
TSCA Public Docket Office, USEPA. August 9, 1999.
    30. Doris Day Animal League. Comments on EPA's TSCA section 
4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption Rate 
Testing of Certain Chemicals of Interest to OSHA submitted to the TSCA 
Public Docket Office, USEPA. August 9, 1999.
    31. Chlorobenzene Producers Association. Comments on EPA's TSCA 
section 4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption 
Rate Testing of Certain Chemicals of Interest to OSHA submitted to the 
TSCA Public Docket Office, USEPA. August 9, 1999.
    32. Tetrahydrofuran Task Force. Comments on EPA's TSCA section 
4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption Rate 
Testing of Certain Chemicals of Interest to OSHA submitted to the TSCA 
Public Docket Office, USEPA. August 9, 1999.
    33. Private Citizen. Comments on EPA's TSCA section 4(a)(1)(B) 
Proposed Test Rule for In Vitro Dermal Absorption Rate Testing of 
Certain Chemicals of Interest to OSHA submitted to the TSCA Public 
Docket Office, USEPA. June 15, 1999.
    34. ACC Naphthalene Panel. Comments on EPA's TSCA section 
4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption Rate 
Testing of Certain Chemicals of Interest to OSHA submitted to the TSCA 
Public Docket Office, USEPA. August 9, 1999.
    35. ACC Propylene Glycol Ethers Panel. Comments on EPA's TSCA 
section 4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption 
Rate Testing of Certain Chemicals of Interest to OSHA submitted to the 
TSCA Public Docket Office, USEPA. August 6, 1999.
    36. ACC Olefins Panel. Comments on EPA's TSCA section 4(a)(1)(B) 
Proposed Test Rule for In Vitro Dermal Absorption Rate Testing of 
Certain Chemicals of Interest to OSHA submitted to the TSCA Public 
Docket Office, USEPA. August 9, 1999.
    37. ACC Hydrocarbon Solvents Panel. Comments on EPA's TSCA section 
4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption Rate 
Testing of Certain Chemicals of Interest to OSHA submitted to the TSCA 
Public Docket Office, USEPA. August 9, 1999.
    38. ACC Ketones Panel and Oxo Process Panel. Comments on EPA's TSCA 
section 4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption

[[Page 22433]]

Rate Testing of Certain Chemicals of Interest to OSHA submitted to the 
TSCA Public Docket Office, USEPA. August 9, 1999.
    39. ACC Carbon Disulfide Panel. Comments on EPA's TSCA section 
4(a)(1)(B) Proposed Test Rule for In Vitro Dermal Absorption Rate 
Testing of Certain Chemicals of Interest to OSHA submitted to the TSCA 
Public Docket Office, USEPA. August 9, 1999.
    40. Buell, D.A., Blaustein, M.B., and Lynch, J.R. An Assessment of 
the National Occupational Exposure Survey. Prepared by Temple, Barker & 
Sloane, Inc. and Exxon Corp. Undated.
    41. Seta, J.A., Sundin, D.S., and Pedersen, D.H. National 
Occupational Exposure Survey Field Guidelines. National Institute for 
Occupational Safety and Health, Cincinnati, OH. DHHS (NIOSH) 
Publication No. 88-106. 1988.
    42. USEPA, Office of Research and Development. Dermal Exposure 
Assessment: Principles and Applications. EPA/600/8-91/011B. January 
1992.
    43. USEPA. Voluntary Children's Chemical Evaluation Program. 
Federal Register (65 FR 81699, December 26, 2000) (FRL-6758-5).
    44. OECD, Paris. Guidance Document for the Conduct of In Vitro Skin 
Absorption Studies. (Draft). April 1999.
    45. Harrison, S.M., Barry, B.W., and Dugard, P.H. Effects of 
freezing on human skin permeability. Journal of Pharmacy and 
Pharmacology. 36: 261. 1984.
    46. USEPA. Laboratory Capacity and the HPV Challenge Program. OPPT/
EETD/EPAB, Washington, DC. October 14, 1999.
    47. Union Carbide Corporation (now Dow Corporation). A letter from 
Dr. Imogene Treble to Frank Kover, USEPA transmitting a study entitled 
Primary Amyl Acetate, Mixed Isomers: In Vitro Percutaneous Absorption 
Study in Human Skin. July 5, 2000.
    48. USEPA. Proposed Test Rule for Hazardous Air Pollutants. Federal 
Register (61 FR 33178, June 26, 1996) (FRL-4869-1).
    49. National Institute for Occupational Safety and Health. National 
Occupational Exposure Survey. March 29, 1989.
    50. Riviere, J.E., Brooks, J.D., Qiao, G.L., and Monteiro-Riviere, 
N.A. Percutaneous Absorption of Volatile Chemicals. Prepared by North 
Carolina State University, Raleigh, NC for AFSOR/NL, Bolling AFB, 
Washington, DC. NTIS number ADA332910. November 1997.
    51. USEPA. Data Collection and Development on High Production 
Volume (HPV) Chemicals. Federal Register (65 FR 81686, December 26, 
2000) (FRL-6754-6).
    52. USEPA. EPA Census of TSCA Testing Laboratories. Prepared by 
OPPT, EETD, EPAB, Washington, DC. October 10, 1996.
    53. USEPA. Analysis of U.S. Laboratory Capacity for Developmental 
and Reproductive Toxicity Testing and the Impact of Expanded TSCA Test 
Rules. Prepared by OPPT/EETD/EPAB, Washington, DC. May 28, 1999.
    54. USEPA. ChemRTK, HPV Challenge Program Chemical List. Prepared 
by OPPT. (This list is updated periodically, and is available 
electronically at http://www.epa.gov/chemrtk/hpvchmlt.htm)
    55. USEPA. TSCA section 4(a)(1)(B) Final Statement of 
Policy.Federal Register (58 FR 28736, May 14, 1993) (FRL-4059-9).
    56. USEPA. Information on OSHA Dermal Test Rule Chemicals: TRI 
Release Data and Number of Workers Exposed. Prepared by OPPT/EETD/
Chemical Engineering Branch (CEB), Washington, DC. April 24, 2001 and 
March 1998.
    57. USEPA. Economic Impact Analysis and Small Entity Impact 
Analysis of the TSCA Section 4(a) Test Rule for 34 Chemicals Targeted 
for In Vitro Dermal Absorption Rate Testing. Prepared by OPPT/EETD/
EPAB, Washington, DC. February 3, 2004.
    58. USEPA. Guidelines for Exposure Assessment. Federal Register (57 
FR 22888, May 29, 1992) (FRL-4129-5).
    59. Small Business Administration, Office of Size Standards. Small 
Business Size Standards matched to North American Industry 
Classification System (NAICS). On website: http://www.sba.gov/size/sizetable2002.html.
    60. USEPA. Treatment of 12(b) Export Notification Unit Costs for 
section 4 Test Rule Analyses. Prepared by Lynne Blake-Hedges OPPT/EETD/
EPAB, Washington, DC. April 1, 1999.
    61. USEPA. Economic Analysis in Support of the TSCA 12(b) 
Information Collection Request. Prepared by Joseph Callahan OPPT/EETD/
EPAB, Washington, DC. October 30, 1998.
    62. OSHA. OSHA dermal test rule. Electronic mail from Val Schaeffer 
to Keith Cronin, USEPA. May 22, 2000.
    63. OSHA. Dermal rule. Electronic mail from Val Schaeffer to Keith 
Cronin, USEPA. March 20, 2002.
    64. OSHA. Dermal rule. Electronic mail from Val Schaeffer to Keith 
Cronin, USEPA. August 25, 2000.
    65. Scheuplein, R.J. and Blank, I.H. Mechanism of percutaneous 
absorption. IV. Penetration of nonelectrolytes (alcohols) from aqueous 
solutions and from pure liquids. Journal of Investigative Dermatology. 
60:286-296. 1973.
    66. USEPA. Wage Rates for Economic Analysis of the Toxics Release 
Inventory Program. Prepared by Cody Rice, Analytical Support Branch, 
Environmental Analysis Division, Office of Environmental Information. 
April 11, 2002.
    67. USEPA. Review of comments received on proposed dermal 
absorption test rule. Memorandum from Greg Macek, CEB to Keith Cronin, 
Chemical Control Division. October 8, 1999.
    68. USEPA. Office of Water Chemicals; Final Test Rule.Federal 
Register (58 FR 59667, November 10, 1993) (FRL-4047-2).
    69. USEPA. Testing Consent Agreements and Test Rules; Final 
Rule.Federal Register (55 FR 18881, May 7, 1990) (FRL-3687-6).
    70. USEPA. Amended Proposed Test Rule for Hazardous Air Pollutants; 
Extension of Comment Period. Federal Register (62 FR 67465, December 
24, 1997) (FRL-5742-2).
    71. USEPA. Inventory Reporting Requirements; Final Rule. Federal 
Register (42 FR 64571, December 23, 1977) (FRL-817-1).
    72. USEPA. Office of Solid Waste Chemicals; Final Test Rule.Federal 
Register (53 FR 22300, June 15, 1988) (FRL-3396-8).
    73. USEPA. Amended Proposed Test Rule for Hazardous Air Pollutants; 
Extension of Comment Period. Federal Register (63 FR 19694, April 21, 
1998) (FRL-5780-6).
    74. USEPA. Toxic Substances; Test Rule Development and Exemption 
Procedures. Federal Register (50 FR 20652, May 17, 1985) (FRL-2809-7).
    75. USEPA. Methylcyclopentane and Commercial Hexane; Proposed Test 
Rule. Federal Register (51 FR 17854, May 15, 1986) (FRL-3008-8).
    76. USEPA. Commercial Hexane and Methylcyclopentane; Final Test 
Rule. Federal Register (53 FR 3382, February 5, 1988) (FRL-3325-1).
    77. USEPA. Toxic Substances; Biphenyl; Final Test Rule.Federal 
Register (50 FR 37182, September 12, 1985) (FRL-2871-5).
    78. USEPA. Office of Water Chemicals, Final Test Rule; 
Clarification. Federal Register (59 FR 45629, September 2, 1994) (FRL-
4047-2).
    79. USEPA. Toxic Substances Control Act; Data Reimbursement.Federal 
Register (48 FR 31785 July 11, 1983) (FRL-2349-8).

[[Page 22434]]

X. Statutory and Executive Order Reviews

A. Paperwork Reduction Act

    The information collection requirements contained in TSCA section 4 
test rules have already been approved by OMB under the provisions of 
the Paperwork Reduction Act, 44 U.S.C. 3501 et seq., and have been 
assigned OMB control number 2070-0033 (EPA ICR No. 1139). The 
information collection activities related to export notification under 
TSCA section 12(b)(1) are already approved under OMB control number 
2070-0030 (EPA ICR No. 0795). This final rule does not contain any new 
or amended requirements that would require additional review and/or 
approval by OMB.
    The standard chemical testing program involves the submission of 
letters of intent to test (or exemption applications), study plans, 
progress reports, and test results. EPA estimates that the information 
collection activities related to chemical testing for all chemicals in 
this final rule (representing the submission of letters of intent or 
exemption applications, study plans, and the final reports; progress 
reports are not required by this final rule because testing will be 
completed within about 1 year) would result in an annual public 
reporting burden of 165 hours per chemical or a total of 5,610 hours 
for the 34 chemicals (Ref. 57).
    The annual public reporting burden related to export notification 
is estimated to be 0.5 to 1.5 burden hours for each chemical/country 
combination (Ref. 57). In estimating the total burden hours approved 
for the information collection activities related to export 
notification, the Agency has included sufficient burden hours to 
accommodate any export notifications that may be required by the 
Agency's issuance of final chemical test rules (Refs. 57, 60, and 61).
    For each manufacturer of the 34 chemicals identified in the 
economic analysis, the parent company (ultimate corporate entity, or 
UCE) was also identified. The economic analysis identified a total of 
84 UCEs that EPA believes would be the likely respondents to the final 
rule. The public reporting burden for this collection of information is 
estimated to average 165 hours per chemical. Multiplying by 34 
chemicals (34 x 165 = 5,610 hours total), and dividing by 84 UCEs, 
results in a per respondent estimated burden of 66.8 hours. This burden 
estimate includes time for reviewing instructions, searching existing 
data sources, gathering and maintaining the data needed, and completing 
and reviewing the collection of information.
    As defined by PRA and 5 CFR 1320.3(b), ``burden'' means the total 
time, effort, or financial resources expended by persons to generate, 
maintain, retain, or disclose or provide information to or for a 
Federal Agency. This includes the time needed to: Review instructions; 
develop, acquire, install, and utilize technology and systems for the 
purposes of collecting, validating, and verifying information, 
processing and maintaining information, and disclosing and providing 
information; adjust the existing ways to comply with any previously 
applicable instructions and requirements which have subsequently 
changed; train personnel to be able to respond to a collection of 
information; search data sources; complete and review the collection of 
information; and transmit or otherwise disclose the information.
    Under PRA, an agency may not conduct or sponsor, and a person is 
not required to respond to, an information collection request unless it 
displays a currently valid OMB control number. The OMB control numbers 
for EPA's regulations are listed in 40 CFR part 9 and included on the 
related collection instrument. EPA is amending the table in 40 CFR part 
9 to list the OMB approval number for the information collection 
requirements contained in this final rule. This listing of the OMB 
control numbers and their subsequent codification in the CFR satisfies 
the display requirements of PRA and OMB's implementing regulations at 5 
CFR part 1320. This ICR was previously subject to public notice and 
comment prior to OMB approval, and given the technical nature of the 
table, EPA finds that further notice and comment to amend it is 
unnecessary. As a result, EPA finds that there is ``good cause'' under 
section 553(b)(1)(B) of the Administrative Procedure Act, 5 U.S.C. 
553(b)(1)(B), to amend this table without further notice and comment.

B. Regulatory Flexibility Act (RFA)

    Pursuant to section 605(b) of the Regulatory Flexibility Act (RFA), 
5 U.S.C. 601 et seq., the Agency hereby certifies that this final rule 
will not have a significant adverse economic impact on a substantial 
number of small entities. The factual basis for the Agency's 
determination is presented in the small entity impact analysis prepared 
as part of the economic analysis for this final rule (Ref. 57), and is 
briefly summarized here.
    Three factors are examined in EPA's small entity assessment (Ref. 
57) in order to characterize the potential small entity impacts of this 
final rule:
     The size of the adverse impact (measured as the 
ratio of the cost to sales or revenue).
     The total number of small entities that 
experience the adverse impact.
     The percentage of the total number of small 
entities that experience the adverse impact.
    Section 601(3) of RFA establishes as the default definition of 
``small business'' the definition used in section 3 of the Small 
Business Act, 15 U.S.C. 632, under which the SBA establishes small 
business size standards for each industry sector. (13 CFR 121.201). For 
this final rule, EPA has analyzed the potential small business impacts 
using the size standards established under this default definition. The 
SBA size standards, which are primarily intended to determine whether a 
business entity is eligible for government programs and preferences 
reserved for small businesses (13 CFR 121.101), ``seek to ensure that a 
concern that meets a specific size standard is not dominant in its 
field of operation.'' (13 CFR 121.102(b)). See section 632(a)(1) of the 
Small Business Act. Industrial sectors are identified by a NAICS code. 
In most cases, SBA has specified an employee size standard (100; 500; 
750; 1,000; or 1,500 employees) or, in some cases, a sales-based, or 
other industry-specific indicator, cut-off below which an entity in 
that particular NAICS code would be considered small (Ref. 59).
    The SBA employee size standards that apply to most of the NAICS 
codes that are potentially impacted (Ref. 57) by this final rule range 
from 500 to 1,500 employees. Size standards for three potentially 
affected non-manufacturing NAICS are defined in terms of sales, and in 
each case the standards are $5 million in annual sales, while the 
standards for the set of possible NAICS where another entity is likely 
to fall, are expressed in terms of electricity generating capacity (4 
million megawatt hours).
    Sales and employment data were obtained for the 84 UCEs that 
manufacture the 34 chemicals subject to this final rule to identify 
those UCEs that qualify for ``small business'' status, where data were 
available. Based on the SBA size standards for the NAICS codes that 
applied to those UCEs, 25 of the 84 UCEs (30%) were identified as 
small. The significance of this final rule's impact on these small 
businesses was analyzed by examining the number of small entities that 
experienced different levels of costs as a percentage of their sales. 
In such an analysis, small businesses are placed in the following

[[Page 22435]]

categories on the basis of cost-to-sales ratios: less than 1.0%, 1.0% 
but less than 3.0%, and 3.0% or greater. Of the 25 companies that 
qualified for small business status according to the SBA size 
standards, none had a cost-to-sales ratio that exceeded 1.0%. Given 
these results, EPA concludes that there is not a significant economic 
impact on these small entities as a result of this final rule.
    There were an additional seven UCEs for which the NAICS code, 
sales, and employment data were not available. Because of this, EPA 
could not determine whether they are small businesses or assess the 
potential impacts of the test rule on them. However, it is very 
unlikely that all seven of these UCEs are small entities. Moreover, 
given the Agency's analysis for the identified small businesses, which 
concluded that there is not a significant economic impact on any of 
them, EPA believes it is reasonable to conclude that even if some of 
these seven UCEs are small entities, they will not experience a 
significant economic impact. Consequently, EPA concludes that there 
will not be a significant economic impact on a substantial number of 
small entities as a result of this final rule.
    In analyzing potential impacts on small entities, RFA recognizes 
that it may be appropriate at times to use an alternate definition of 
small business. As such, section 601(3) of RFA provides that an agency 
may establish a different definition of small business after 
consultation with the SBA Office of Advocacy and after notice and an 
opportunity for public comment. Even though the Agency has used the 
default SBA definition of small business to conduct its analysis of 
potential small entity impacts for this final rule, EPA does not 
believe that the SBA size standards are generally the best standards to 
use in assessing potential impacts of TSCA section 4(a) test rules on 
small entities. EPA believes that a standard based on total annual 
sales, such as the definition found in TSCA (40 CFR 704.3), may provide 
a more appropriate means to determine the ability of a chemical 
manufacturing firm to support testing without significant costs or 
burdens. EPA is determining what level of annual sales would provide 
the most appropriate size cutoff with regard to various segments of the 
chemical industry usually impacted by TSCA section 4(a) test rules, but 
has not yet reached a determination. Therefore, as previously stated in 
this unit, the RFA determination for this final rule is based on an 
analysis using the default SBA size standards. In the proposal to this 
rule, EPA requested comment on whether the Agency should establish an 
alternate small business definition to use in small entity impact 
analyses for future TSCA section 4(a) test rules, and what size cutoff 
may be appropriate. The comment received on this subject and the 
Agency's response are in Unit III.K.
    Although EPA has not yet pursued the establishment of an alternate 
definition for use in the analysis conducted for this final rule, the 
analysis does present the results of calculations using a standard 
based on total annual sales. Under the TSCA definition at 40 CFR 704.3, 
a firm is classified as small if it has either total annual sales below 
$40 million and annual production or importation volume less than or 
equal to 100,000 pounds, or, annual sales below $4 million. Of the 84 
UCEs subject to the final rule, a maximum of 9 can be classified as 
small under the TSCA definition, with data unavailable for an 
additional 7 firms. None of those 9 firms will be affected at the level 
of 1.0% or greater. Impacts could not be determined for the 7 firms 
whose size was unknown, but as with the analysis conducted using the 
SBA size standards, the Agency believes it is reasonable to conclude 
that under the referenced TSCA definition of small, the 7 UCEs will not 
experience significant economic impacts as a result of the final rule.
    The estimated costs of the TSCA section 12(b) export notification, 
which, as a result of this final rule, would be required for the first 
export to a particular country of a chemical subject to the rule, is 
estimated to be $61.31 for the first time that an exporter must comply 
with TSCA section 12(b) export notification requirements, and $18.07 
for each subsequent export notification submitted by that exporter 
(Refs. 57, 60, and 61). EPA has concluded that the costs of TSCA 
section 12(b) export notification would have a negligible impact on 
exporters of the chemicals in this final rule, regardless of the size 
of the exporter.
    Therefore, the Agency certifies that this final rule will not have 
a significant adverse economic impact on a substantial number of small 
entities.

C. Unfunded Mandates Reform Act

    Pursuant to Title II of the Unfunded Mandates Reform Act of 1995 
(Public Law 104-4), EPA has determined that this regulatory action does 
not contain a Federal mandate that may result in expenditures of $100 
million or more for State, local, and tribal governments, in the 
aggregate, or for the private sector in any 1 year. The analysis of the 
costs associated with this action are described in Unit VIII. In 
addition, since EPA does not have any information to indicate that any 
State, local, or tribal government manufactures or processes the 
chemicals covered by this action such that this final rule would apply 
directly to State, local, or tribal governments, EPA has determined 
that this final rule does not significantly or uniquely affect small 
governments. Accordingly, this final rule is not subject to the 
requirements of sections 202, 203, 204, and 205 of UMRA.

D. Executive Order 13132

    Executive Order 13132, entitled Federalism (64 FR 43255, August 10, 
1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' is defined in the 
Executive order to include regulations that have ``substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government.''
    This final rule does not have federalism implications. It will not 
have substantial direct effects on the States, on the relationship 
between the national government and the States, or on the distribution 
of power and responsibilities among the various levels of government, 
as specified in Executive Order 13132. This final rule establishes 
testing and recordkeeping requirements that apply to manufacturers 
(including importers) and processors of certain chemicals. Because EPA 
has no information to indicate that any State or local government 
manufactures or processes the chemical substances covered by this 
action, this final rule does not apply directly to States and 
localities and will not affect State and local governments. Thus, 
Executive Order 13132 does not apply to this final rule. Although 
Executive Order 13132 was not yet in effect when EPA developed the 
proposed rule, its predecessor, Executive Order 12875, was and EPA's 
conclusions under Executive Order 13132 are consistent with EPA's 
considerations under Executive Order 12875.

E. Executive Order 13175

    Under Executive Order 13175, entitled Consultation and Coordination 
with Indian Tribal Governments (65 FR 67249, November 6, 2000), this 
final rule does not have tribal implications

[[Page 22436]]

because it will not have substantial direct effects on tribal 
governments, on the relationship between the Federal Government and the 
Indian tribes, or on the distribution of power and responsibilities 
between the Federal Government and Indian tribes, as specified in the 
Order. As indicated above, EPA has no information to indicate that any 
tribal government manufactures or processes the chemical substances 
covered by this action. Thus, Executive Order 13175 does not apply to 
this final rule. Although Executive Order 13175 was not yet in effect 
when EPA developed the proposed rule, its predecessor, Executive Order 
13084, was and EPA's conclusions under Executive Order 13175 are 
consistent with EPA's considerations under Executive Order 13084.

F. Executive Order 13045

    This final rule does not require special consideration pursuant to 
the terms of Executive Order 13045, entitled Protection of Children 
from Environmental Health Risks and Safety Risks (62 FR 19885, April 
23, 1997), because it is not likely to have an annual effect on the 
economy of $100 million or more and it does not have a potential effect 
or impact on children. This final rule establishes testing and 
recordkeeping requirements that apply to manufacturers (including 
importers) and processors of certain chemicals, and will result in the 
production of information that will assist the Agency and others in 
determining whether the chemical substances in this final rule present 
potential risks, allowing the Agency and others to take appropriate 
action to investigate and mitigate those risks.

G. Executive Order 13211

    This final rule is not a ``significant energy action'' as defined 
in Executive Order 13211, Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use (66 FR 28355, 
May 22, 2001) because it is not likely to have a significant adverse 
effect on the supply, distribution, or use of energy. As such, the 
Agency has concluded that this final rule is not likely to have adverse 
energy effects.

H. National Technology Transfer and Advancement Act

    As noted in the proposed rule, section 12(d) of the National 
Technology Transfer and Advancement Act of 1995 (NTTAA), Public Law 
104-113 section 12(d) (15 U.S.C 272 note) directs EPA to use voluntary 
consensus standards in its regulatory activities unless to do so would 
be inconsistent with applicable law or otherwise impractical. Voluntary 
consensus standards are technical standards (e.g., materials 
specifications, test methods, sampling procedures, and business 
practices) that are developed or adopted by voluntary consensus 
standards bodies. The NTTAA directs EPA to provide Congress, through 
OMB, explanations when the Agency decides not to use available and 
applicable voluntary consensus standards.
    Because this final rule involves technical standards, the Agency 
conducted a search to identify potentially applicable voluntary 
consensus standards. No such standards were identified and none were 
brought to the Agency's attention in comments. Therefore, EPA has 
decided to use the in vitro dermal absorption rate test standard 
finalized in this document. This standard was based on the peer 
reviewed method of Bronaugh and Collier which was published in 1991 
(Ref. 13) and refined by a panel of Federal scientists from ITC member 
and liaison agencies (including, for example, CPSC, DoD, EPA, FDA, 
NIOSH, and OSHA). The method was further refined by this panel in 
response to public comments.

I. Executive Order 12898

    Pursuant to Executive Order 12898, entitled Federal Actions to 
Address Environmental Justice in Minority Populations and Low-Income 
Populations (59 FR 7629, February 16, 1994), the Agency has considered 
environmental justice-related issues with regard to the potential 
impacts of this action on the environmental and health conditions in 
minority and low-income populations. The Agency believes that the 
information collected under this final rule will assist EPA and others 
in determining the hazards and risks associated with the chemicals 
covered by the final rule. Although not directly impacting 
environmental justice-related concerns, this information will better 
enable the Agency to protect human health and the environment.

J. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., generally 
provides that before a rule may take effect, the Agency promulgating 
the rule must submit a rule report to each House of the Congress and 
the Comptroller General of the United States. EPA will submit a report 
containing this rule and other required information to the U.S. Senate, 
the U.S. House of Representatives, and the Comptroller General of the 
United States prior to publication of the rule in the Federal Register. 
This rule is not a ``major rule'' as defined by 5 U.S.C. 804(2).

List of Subjects

40 CFR Part 9
    Environmental protection, Reporting and recordkeeping requirements.
40 CFR Part 799
    Environmental protection, Chemicals, Hazardous substances, 
Laboratories, Reporting and recordkeeping requirements.


    Dated: April 4, 2004.
Susan B. Hazen,
Acting Assistant Administrator, Office of Prevention, Pesticides and 
Toxic Substances.


0
Therefore, 40 CFR chapter I is amended as follows:
0
1. By amending part 9 as follows:

PART 9--[AMENDED]

0
a. The authority citation for part 9 continues to read as follows:

    Authority: 7 U.S.C. 135 et seq., 136-136y; 15 U.S.C. 2001, 2003, 
2005, 2006, 2601-2671; 21 U.S.C. 331j, 346a, 348; 31 U.S.C. 9701; 33 
U.S.C. 1251 et seq., 1311, 1313d, 1314, 1318, 1321, 1326, 1330, 
1342, 1344, 1345 (d) and (e), 1361; E.O. 11735, 38 FR 21243, 3 CFR, 
1971-1975 Comp. p. 973; 42 U.S.C. 241, 242b, 243, 246, 300f, 300g, 
300g-1, 300g-2, 300g-3, 300g-4, 300g-5, 300g-6, 300j-1, 300j-2, 
300j-3, 300j-4, 300j-9, 1857 et seq., 6901-6992k, 7401-7671q, 7542, 
9601-9657, 11023, 11048.


0
b. In Sec.  9.1, the table is amended by adding an entry for Sec.  
799.5115 in numerical order under the indicated heading to read as 
follows:


Sec.  9.1  OMB approvals under the Paperwork Reduction Act.

* * * * *

------------------------------------------------------------------------
                                                            OMB control
                     40 CFR citation                            No.
------------------------------------------------------------------------
                                * * * * *
    Identification of Specific Chemical Substance and Mixture Testing
                              Requirements
 
------------------------------------------------------------------------
                                * * * * *
799.5115................................................       2070-0033
                                * * * * *
------------------------------------------------------------------------

* * * * *

0
2. By amending part 799 as follows:

PART 799--[AMENDED]

0
a. The authority citation for part 799 continues to read as follows:

    Authority: 15 U.S.C. 2603, 2611, 2625.


0
b. By adding Sec.  799.5115 to subpart D to read as follows:

[[Page 22437]]

Sec.  799.5115  Chemical testing requirements for certain chemicals of 
interest to the Occupational Safety and Health Administration.

    (a) What substances will be tested under this section? Table 2 in 
paragraph (j) of this section identifies the chemical substances that 
must be tested under this section. For the chemical substances 
identified as ``Class 1'' substances in Table 2 in paragraph (j) of 
this section, the purity of each chemical substance must be 99% or 
greater, unless otherwise specified in this section. For the chemical 
substances identified as ``Class 2'' substances in Table 2 in paragraph 
(j) of this section, a representative form of each chemical substance 
must be tested.
    (b) Am I subject to this section? (1) If you manufacture (including 
import) or intend to manufacture, or process or intend to process, any 
chemical substance listed in Table 2 in paragraph (j) of this section 
at any time from May 26, 2004, to the end of the test data 
reimbursement period as defined in 40 CFR 791.3(h), you are subject to 
this section with respect to that chemical substance.
    (2) If you do not know or cannot reasonably ascertain that you 
manufacture or process a chemical substance listed in Table 2 in 
paragraph (j) of this section during the time period described in 
paragraph (b)(1) of this section (based on all information in your 
possession or control, as well as all information that a reasonable 
person similarly situated might be expected to possess, control, or 
know, or could obtain without an unreasonable burden), you are not 
subject to this section with respect to that chemical substance.
    (c) If I am subject to this section, when must I comply with it? 
(1)(i) Persons subject to this section are divided into two groups, as 
set forth in Table 1 of this paragraph: Tier 1 (persons initially 
required to comply) and Tier 2 (persons not initially required to 
comply). If you are subject to this section, you must determine if you 
fall within Tier 1 or Tier 2, based on Table 1 of this paragraph.

   Table 1.--Persons Subject to the Rule: Persons in Tier 1 and Tier 2
------------------------------------------------------------------------
                                          Persons not initially required
  Persons initially required to comply     to comply with this section
       with this section (Tier 1)                    (Tier 2)
------------------------------------------------------------------------
Persons not otherwise specified in       A. Persons who manufacture (as
 column 2 of this table that              defined at TSCA section 3(7))
 manufacture (as defined at TSCA          or intend to manufacture a
 section 3(7)) or intend to manufacture   chemical substance included in
 a chemical substance included in this    this section solely as one or
 section.                                 more of the following:
                                         --As a byproduct (as defined at
                                          40 CFR 791.3(c));
                                         --As an impurity (as defined at
                                          40 CFR 790.3);
                                         --As a naturally occurring
                                          substance (as defined at 40
                                          CFR 710.4(b));
                                         --As a non-isolated
                                          intermediate (as defined at 40
                                          CFR 704.3);
                                         --As a component of a Class 2
                                          substance (as described at 40
                                          CFR 720.45(a)(1)(i));
                                         --In amounts of less than 500
                                          kilograms (kg) (1,100 lbs)
                                          annually (as described at 40
                                          CFR 790.42(a)(4)); or
                                         --For research and development
                                          (as described at 40 CFR
                                          790.42(a)(5)).
                                         B. Persons who process (as
                                          defined at TSCA section 3(10))
                                          or intend to process a
                                          chemical substance included in
                                          this section (see 40 CFR
                                          790.42(a)(2)).
------------------------------------------------------------------------

    (ii) Table 1 in paragraph (c)(1)(i) of this section expands the 
list of persons specified in Sec.  790.42(a)(2), (a)(4), and (a)(5) of 
this chapter, who, while legally subject to this section, must comply 
with the requirements of this section only if directed to do so by EPA 
under the circumstances set forth in paragraphs (c)(4) through (c)(7) 
and (c)(10) of this section.
    (2) If you are in Tier 1 with respect to a chemical substance 
listed in Table 2 in paragraph (j) of this section, you must, for each 
test required under this section for that chemical substance, either 
submit to EPA a letter of intent to test or apply to EPA for an 
exemption from testing. The letter of intent to test or the exemption 
application must be received by EPA no later than June 25, 2004.
    (3) If you are in Tier 2 with respect to a chemical substance 
listed in Table 2 in paragraph (j) of this section, you are considered 
to have an automatic conditional exemption and you will be required to 
comply with this section with regard to that chemical substance only if 
directed to do so by EPA under paragraphs (c)(5), (c)(7), or (c)(10) of 
this section.
    (4) If no person in Tier 1 has notified EPA of its intent to 
conduct one or more of the tests required by this section on any 
chemical substance listed in Table 2 in paragraph (j) of this section 
by June 25, 2004, EPA will publish a Federal Register document that 
would specify the test(s) and the chemical substance(s) for which no 
letter of intent has been submitted, and notify manufacturers in Tier 
2A of their obligation to submit a letter of intent to test or to apply 
for an exemption from testing.
    (5) If you are in Tier 2A with respect to a chemical substance 
listed in Table 2 in paragraph (j) of this section, and if you 
manufacture this chemical substance as of May 26, 2004, or within 30 
days after publication of the Federal Register document described in 
paragraph (c)(4) of this section, you must, for each test specified for 
that chemical substance in the document described in paragraph (c)(4) 
of this section, either submit to EPA a letter of intent to test or 
apply to EPA for an exemption from testing. The letter of intent to 
test or the exemption application must be received by EPA no later than 
30 days after publication of the document described in paragraph (c)(4) 
of this section.
    (6) If no manufacturer in Tier 1 or Tier 2A has notified EPA of its 
intent to conduct one or more of the tests required by this section on 
any chemical substance listed in Table 2 in paragraph (j) of this 
section within 30 days after the publication of the Federal Register 
document described in paragraph (c)(4) of this section, EPA will 
publish another Federal Register document that would specify the 
test(s) and the chemical substance(s) for which no letter of intent has 
been submitted, and notify processors in Tier 2B of their obligation to 
submit a letter of intent to test or to apply for an exemption from 
testing.
    (7) If you are in Tier 2B with respect to a chemical substance 
listed in Table 2 in paragraph (j) of this section, and if you process 
this chemical substance as of May 26, 2004, or within 30 days after 
publication of the Federal Register document described in paragraph 
(c)(6) of this section, you must, for each test specified for that 
chemical substance in the document described in paragraph (c)(6) of 
this section, either submit to EPA a letter of intent to test or apply 
to EPA for an exemption from testing. The

[[Page 22438]]

letter of intent to test or the exemption application must be received 
by EPA no later than 30 days after publication of the document 
described in paragraph (c)(6) of this section.
    (8) If no manufacturer or processor has notified EPA of its intent 
to conduct one or more of the tests required by this section for any of 
the chemical substances listed in Table 2 in paragraph (j) of this 
section within 30 days after the publication of the Federal Register 
document described in paragraph (c)(6) of this section, EPA will notify 
all manufacturers and processors of those chemical substances of this 
fact by certified letter or by publishing a Federal Register document 
specifying the test(s) for which no letter of intent has been 
submitted. This letter or Federal Register document will additionally 
notify all manufacturers and processors that all exemption applications 
concerning the test(s) have been denied, and will give the 
manufacturers and processors of the chemical substance(s) an 
opportunity to take corrective action.
    (9) If no manufacturer or processor has notified EPA of its intent 
to conduct one or more of the tests required by this section for any of 
the chemical substances listed in Table 2 in paragraph (j) of this 
section within 30 days after receipt of the certified letter or 
publication of the Federal Register document described in paragraph 
(c)(8) of this section, all manufacturers and processors subject to 
this section with respect to that chemical substance who are not 
already in violation of this section will be in violation of this 
section.
    (10) If a problem occurs with the initiation, conduct, or 
completion of the required testing or the submission of the required 
data with respect to a chemical substance listed in Table 2 in 
paragraph (j) of this section, under the procedures in Sec.  Sec.  
790.93 and 790.97 of this chapter, EPA may initiate termination 
proceedings for all testing exemptions with respect to that chemical 
substance and may notify persons in Tier 1 and Tier 2 that they are 
required to submit letters of intent to test or exemption applications 
within a specified period of time.
    (11) If you are required to comply with this section, but your 
manufacturing or processing of a chemical substance listed in Table 2 
in paragraph (j) of this section begins after the applicable compliance 
date referred to in paragraphs (c)(2), (c)(5), (c)(7), or (c)(10) of 
this section, you must either submit a letter of intent to test or 
apply to EPA for an exemption. The letter of intent to test or the 
exemption application must be received by EPA no later than the day you 
begin manufacturing or processing.
    (d) What must I do to comply with this section? (1) To comply with 
this section you must either submit to EPA a letter of intent to test, 
or apply to and obtain from EPA an exemption from testing.
    (2) For each test with respect to which you submit to EPA a letter 
of intent to test, you must conduct the testing specified in paragraph 
(h) of this section and submit the test data to EPA.
    (3) You must also comply with the procedures governing test rule 
requirements in part 790 of this chapter, as modified by this section, 
including the submission of letters of intent to test or exemption 
applications, the conduct of testing, and the submission of data; Part 
792--Good Laboratory Practice Standards of this chapter; and this 
section. The following provisions of 40 CFR part 790 do not apply to 
this section: Paragraphs (a), (d), (e), and (f) of Sec.  790.45; 
paragraph (a)(2) and paragraph (b) of Sec.  790.80; and Sec.  790.48.
    (e) If I do not comply with this section, when will I be considered 
in violation of it? You will be considered in violation of this section 
as of 1 day after the date by which you are required to comply with 
this section.
    (f) How are EPA's data reimbursement procedures affected for 
purposes of this section? If persons subject to this section are unable 
to agree on the amount or method of reimbursement for test data 
development for one or more chemical substances included in this 
section, any person may request a hearing as described in 40 CFR part 
791. In the determination of fair reimbursement shares under this 
section, if the hearing officer chooses to use a formula based on 
production volume, the total production volume amount will include 
amounts of a chemical substance produced as an impurity.
    (g) Who must comply with the export notification requirements? Any 
person who exports, or intends to export, a chemical substance listed 
in Table 2 in paragraph (j) of this section is subject to part 707, 
subpart D, of this chapter.
    (h) How must I conduct my testing? The chemical substances 
identified by Chemical Abstract Service Registry Number (CAS No.) and 
chemical name in Table 2 in paragraph (j) of this section must be 
tested as follows:
    (1) Applicability. This in vitro dermal absorption rate test 
standard must be used for all testing conducted under this section. In 
certain instances, modifications to the test standard may be 
considered. The procedures for applying for a modification to the test 
standard are specified in 40 CFR 790.55.
    (2) Source. The test standard is based on the Protocol for In Vitro 
Percutaneous Absorption Rate Studies, referenced in paragraph (h)(8)(v) 
of this section.
    (3) Purpose. In the assessment and evaluation of the 
characteristics of a chemical substance or mixture for which testing is 
required under this section (test substance), it is important to 
determine the rate of absorption of the test substance in cases where 
dermal exposure to the test substance in the workplace may result in 
systemic toxicity. This test standard is designed to develop data that 
describe the rate at which test substances are absorbed through the 
skin so that the body burden of a test substance resulting from dermal 
exposure in the workplace can be better evaluated.
    (4) Principles of the test standard. This test standard describes 
procedures for measuring a permeability constant (Kp) and two short-
term dermal absorption rates for test substances in liquid form. The 
test standard utilizes in vitro diffusion cell techniques which allow 
absorption studies to be conducted with human cadaver skin. In vitro 
diffusion studies are necessary for measuring a Kp. This test standard 
specifies the use of static or flow-through diffusion cells and non-
viable human cadaver skin. It also requires the use of radiolabeled 
test substances unless it can be demonstrated that procedures utilizing 
a non-radiolabeled test substance are able to measure the test 
substance with a sensitivity equivalent to the radiolabeled method.
    (5) Test procedure--(i) Choice of membrane--(A) Skin selection. 
Human cadaver skin must be used in all testing conducted under this 
test standard. This test standard does not require use of live skin, or 
the maintenance of skin viability during the course of the experiment. 
However, the time elapsed between death and harvest of tissue must be 
reported.
    (B) Number of skin samples. Data for the determination of a Kp must 
be obtained from a minimum of six skin samples and the skin samples 
must come from at least three different human subjects (two skin 
samples from each subject) in order to allow for biological variation 
between subjects. Data for the determination of each short-term (i.e., 
10 minute and 60 minute) absorption rate must be obtained from a 
minimum of six skin samples and the skin samples must come from at 
least three different human subjects (two skin samples from each 
subject).

[[Page 22439]]

    (C) Anatomical region. In order to minimize the variability in skin 
absorption measurements for these tests, samples of human cadaver skin 
must be obtained from the abdominal region of human subjects of known 
source and disease state.
    (D) Validation of human cadaver skin barrier. Prior to conducting 
an experiment with the test substance, barrier properties of human 
cadaver skin must be pretested either by:
    (1) Measuring the absorption of a standard compound such as 
tritiated water as discussed, for example, in the reference in 
paragraph (h)(8)(i) of this section;
    (2) Determining an electrical resistance to an alternating current, 
at up to two volts; or
    (3) Measuring trans-epidermal water loss from the stratum corneum.
    (ii) Preparation of membrane. Full thickness skin must not be used. 
A suitable membrane must be prepared from skin either with a dermatome 
at a thickness of 200 to 500 micrometers (um), or with heat separation 
by treating the skin at 60[deg] C for 45 seconds to 2 minutes after 
which the epidermis can be peeled from the dermis. These epidermal 
membranes can be stored frozen (-20[deg] C) for up to 3 months, if 
necessary, if they are frozen quickly and the barrier properties of the 
samples are confirmed immediately prior to commencement of the 
experiment.
    (iii) Diffusion cell design. Either static or flow-through 
diffusion cells must be used in these studies. To ensure that an 
increase in concentration of the test substance in the receptor fluid 
does not alter penetration rate, the testing laboratory must verify 
that the concentration of the test substance in the receptor fluid is 
less than 10% of the initial concentration in the donor chamber. 
Concentration of the neat (i.e., undiluted) liquid must be taken as the 
density of the test substance.
    (iv) Temperature. Skin must be maintained at a physiological 
temperature of 32[deg] C during the test.
    (v) Testing hydrophobic chemicals. When testing hydrophobic 
chemicals, polyethoxyoleate (polyethylene glycol (PEG) 20 oleyl ether) 
must be added to the receptor fluid at a concentration of 6%.
    (vi) Vehicle. If the test substance is a liquid at room temperature 
and does not damage the skin during the determination of Kp, it must be 
applied neat. If the test substance cannot be applied neat because it 
is a solid at room temperature or because it damages the skin when 
applied neat, it must be dissolved in water. If the concentration of a 
hydrophobic test substance in water is not high enough so that a 
steady-state absorption can be obtained, the test substance must be 
dissolved in isopropyl myristate. A sufficient volume of liquid must be 
used to completely cover the skin and provide the amount of test 
substance as described in paragraph (h)(5)(vii) of this section.
    (vii) Dose--(A) Kp. A Kp must be determined for each test chemical. 
An ``infinite dose'' of the test substance must be applied to the skin 
to achieve the steady-state rate of absorption necessary for 
calculation of a Kp. Infinite dose is defined as the concentration of a 
test substance required to give an undepletable reservoir on the 
surface of the skin. The actual concentration required to give an 
undepletable reservoir on the surface of the skin depends on the rate 
of penetration of the test substance. Preliminary studies may be 
necessary to determine this concentration. Percutaneous absorption must 
be determined under occluded (i.e., covered) conditions unless it is 
demonstrated that such conditions cause leakage of material or damage 
to the skin membrane as a result of unrealistically high pressures or 
excessive hydration. Skin barrier integrity must be verified at the end 
of the experiment by the methods discussed in paragraph (h)(5)(i)(D) of 
this section.
    (B) Short-term absorption rates. Short-term absorption rates must 
be determined for all test chemicals. The dose of test chemical applied 
to the skin must be sufficient to completely cover the exposed skin 
surface. A minimum of four diffusion cells must be set up using skin 
from a single subject. Two diffusion cells must be terminated at 10 
minutes. The remaining two diffusion cells must be terminated at 60 
minutes. Skin absorption at each sampling time is the sum of the 
receptor fluid levels and the absorbed test substance that remains in 
the skin, as discussed, for example, in the reference in paragraph 
(h)(8)(iii) of this section. Unabsorbed chemical must be removed from 
the skin surface by washing gently with soap and water. This experiment 
must be repeated with skin from two additional subjects. In order to 
ensure reliable short-term absorption rates, percutaneous absorption 
must be determined under occluded conditions unless it is demonstrated 
that such conditions cause leakage of material or damage to the skin 
membrane as a result of unrealistically high pressures or excessive 
hydration.
    (viii) Study duration--(A) Kp. The in vitro dermal absorption rate 
test must be performed until at least four absorption measurements per 
diffusion cell experiment are obtained during the steady-state 
absorption portion of the experiment. A preliminary study may be useful 
to establish time points for sampling. The required absorption 
measurements can be accomplished in an hour or two with fast-
penetrating chemicals but may require 24 hours or longer for slow-
penetrating chemicals. Unabsorbed test substance need not be removed 
from the surface of the skin after each experiment.
    (B) Short-term absorption rates. The test substance must be applied 
to skin for durations of 10 and 60 minutes. At the end of the study, 
the unabsorbed test substance must be removed from the surface of the 
skin with soap and water and the amount absorbed into the skin and 
receptor fluid must be determined, as discussed, for example, in the 
reference in paragraph (h)(8)(iii) of this section.
    (6) Results--(i) Kp. The Kp must be calculated by dividing the 
steady-state rate of absorption (measured in micrograms (ug) x 
hr-\1\ x centimeters (cm)-\2\) by the 
concentration of the test substance (measured in ug x 
cm-\3\) applied to the skin. (For example, if the steady-
state rate is 1 microgram x hr-\1\ x cm-\2\ and 
the concentration applied to the skin is 1,000 micrograms x 
cm-\3\, then the Kp value is calculated to be 0.001 cm x 
hr-\1\.) The mean and standard deviation of the calculated 
Kp values for all diffusion cell experiments must be determined.
    (ii) Short-term absorption rate. The absorption rates (ug x 
hr-\1\ x cm-\2\) must be determined from the 
total amount of test substance found in the receptor fluid and skin 
after the 10-minute and 60-minute exposures for each diffusion cell 
experiment. The mean and standard deviation of 10-minute short-term 
absorption rates from all experiments must be calculated. The mean and 
standard deviation of 60-minute short-term absorption rates from all 
experiments must also be calculated.
    (7) Test report. In addition to compliance with the TSCA Good 
Laboratory Practice Standards (GLPS) at 40 CFR part 792, the following 
specific information must be collected and reported by the date in 
paragraph (i) of this section:
    (i) Test systems and test methods. (A) A description of the date, 
time, and location of the test, the name(s) of the person(s) conducting 
the test, the location of records pertaining to the test, as well as a 
GLPS statement. These statements must be certified by the signatures of 
the individuals performing the work and their supervisors.

[[Page 22440]]

    (B) A description of the source, identity, and purity of the test 
substance and the source, identity, and handling of the test skin. 
There must be a detailed description of the test procedure and all 
materials, devices used and doses tested, as well as a detailed 
description and illustration of static or flow-through cell design. 
There must also be a description of the skin preparation method, 
including measurements of the skin membrane thickness.
    (C) A description of the analytical techniques to be used, 
including their accuracy, precision, and detection limits (in 
particular for non-radiolabeled tests), and, if a radiolabel is used, 
there must be a description of the radiolabel (e.g., type, location of, 
and radiochemical purity of the label).
    (D) All data must be clearly identified as to dose and specimen. 
Derived values (means, permeability coefficient, graphs, charts, etc.) 
are not sufficient.
    (ii) Conduct of study. Data must be collected and reported on the 
following:
    (A) Monitoring of testing parameters.
    (B) Temperature of chamber.
    (C) Receptor fluid pH.
    (D) Barrier property validation.
    (E) Analysis of receptor fluid for radioactivity or test chemical
    (iii) Results. The mean Kp and mean short-term absorption rates 
must be presented along with their standard deviations and the number 
of diffusion cell experiments. In addition, all raw data from each 
individual diffusion cell must be retained to support the calculations 
of permeability constants and short-term absorption rates. When a 
radiolabeled test substance is used, a full balance of the 
radioactivity must be presented, including cell rinsing and stability 
of the test substance in the donor compartment.
    (8) References. For background information on this test standard, 
the following references may be consulted. These references are 
available under docket ID number OPPT-2003-0006 at the EPA Docket 
Center, Rm. B102-Reading Room, EPA West, 1301 Constitution Ave., NW., 
Washington, DC, from 8:30 a.m. to 4:30 p.m., Monday through Friday, 
excluding legal holidays.
    (i) Bronaugh, R.L., Stewart, R.F., and Simon, M. Methods for In 
Vitro Percutaneous Absorption Studies VII: Use of Excised Human Skin. 
Journal of Pharmaceutical Sciences. 75:1094-1097. 1986.
    (ii) Bronaugh, R.L. and Stewart, R.F. Methods for In Vitro 
Percutaneous Absorption Studies IV: The Flow-Through Diffusion Cell. 
Journal of Pharmaceutical Sciences. 74:64-67. 1985.
    (iii) Bronaugh, R.L., Stewart, R.F., and Storm, J.E. Extent of 
Cutaneous Metabolism During Percutaneous Absorption of Xenobiotics. 
Toxicology and Applied Pharmacology. 99:534-543. 1989.
    (iv) Walker, J.D., Whittaker, C. and McDougal, J.N. Role of the 
TSCA Interagency Testing Committee in Meeting the U.S. Government Data 
Needs: Designating Chemicals for Percutaneous Absorption Rate Testing. 
Dermatotoxicology. F. Marzulli and H. Maibach, Eds. Taylor & Francis, 
Washington, DC. pp. 371-381. 1996.
    (v) Bronaugh, R.L., and Collier, S.W. Protocol for In Vitro 
Percutaneous Absorption Studies. In Vitro Percutaneous Absorption: 
Principles, Fundamentals, and Applications. R.L. Bronaugh and H.I. 
Maibach, Eds. CRC Press, Boca Raton, FL. pp. 237-241. 1991.
    (i) Reporting requirements. The reports submitted under this 
section must include the information specified in paragraph (h)(7) of 
this section. A final report for each chemical substance must be 
received by EPA by June 27, 2005, unless an extension is granted in 
writing pursuant to 40 CFR 790.55.
    (j) Designation of specific chemical substances for testing. The 
chemical substances identified by chemical name, CAS No., and class in 
Table 2 of this paragraph must be tested in accordance with the testing 
requirements in paragraph (h) of this section and the requirements 
described in 40 CFR part 792.

          Table 2.--Chemical Substances Designated For Testing
------------------------------------------------------------------------
            CAS No.                  Chemical name            Class
------------------------------------------------------------------------
75-05-8                         Acetonitrile            1
-------------------------------
75-15-0                         Carbon disulfide        1
-------------------------------
75-35-4                         Vinylidene chloride     1
-------------------------------
77-73-6                         Dicyclopentadiene       1
-------------------------------
77-78-1                         Dimethyl sulfate        1
-------------------------------
78-59-1                         Isophorone              1
-------------------------------
78-87-5                         Propylene dichloride    1
-------------------------------
79-20-9                         Methyl acetate          1
-------------------------------
79-46-9                         2-Nitropropane          1
-------------------------------
91-20-3                         Naphthalene             1
-------------------------------
92-52-4                         Biphenyl                1
-------------------------------
98-29-3                         tert-Butylcatechol      1
-------------------------------
100-00-5                        p-Nitrochlorobenzene    1
-------------------------------
100-01-6                        p-Nitroaniline          1
-------------------------------
100-44-7                        Benzyl chloride         1
-------------------------------

[[Page 22441]]

 
106-42-3                        p-Xylene                1
-------------------------------
106-46-7                        p-Dichlorobenzene       1
-------------------------------
107-06-2                        Ethylene dichloride     1
-------------------------------
107-31-3                        Methyl formate          1
-------------------------------
108-03-2                        1-Nitropropane          1
-------------------------------
108-90-7                        Chlorobenzene           1
-------------------------------
108-93-0                        Cyclohexanol            1
-------------------------------
109-66-0                        Pentane                 1
-------------------------------
109-99-9                        Tetrahydrofuran         1
-------------------------------
110-12-3                        Methyl isoamyl ketone   1
-------------------------------
111-84-2                        Nonane                  1
-------------------------------
120-80-9                        Catechol                1
-------------------------------
122-39-4                        Diphenylamine           1
-------------------------------
123-42-2                        Diacetone alcohol       1
-------------------------------
127-19-5                        Dimethyl acetamide      1
-------------------------------
142-82-5                        n-Heptane               1
-------------------------------
150-76-5                        p-Methoxyphenol         1
-------------------------------
25013-15-4                      Vinyl toluene           2
-------------------------------
34590-94-8                      Dipropylene glycol      2
                                 methyl ether
------------------------------------------------------------------------

    (k) Effective date This section is effective on May 26, 2004.

[FR Doc. 04-9409 Filed 4-23-04; 8:45 am]
BILLING CODE 6560-50-S