[Federal Register Volume 59, Number 48 (Friday, March 11, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-5752]


[[Page Unknown]]

[Federal Register: March 11, 1994]


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DEPARTMENT OF LABOR

Occupational Safety and Health Administration

29 CFR Parts 1910, 1915 and 1926

[Docket No. H-071A]

 

Occupational Exposure to Methylene Chloride

AGENCY: Occupational Safety and Health Administration (OSHA), 
Department of Labor.

ACTION: Proposed rule; limited reopening of the rulemaking record.

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SUMMARY: The Occupational Safety and Health Administration (OSHA) is 
reopening the record for the proposed revision (NPRM) of the regulation 
of methylene chloride (MC) (56 FR 57036, November 7, 1991) to 
incorporate (1) information regarding engineering controls for MC 
exposure in the furniture stripping industry; (2) a National Cancer 
Institute study of occupational exposure to chlorinated aliphatic 
hydrocarbons and the risk of astrocytic brain cancer; and (3) 
information regarding the use of MC as a solvent in adhesive 
formulations in flexible foam manufacturing. The NPRM and hearing 
notice (57 FR 24438, June 9, 1992) raised concerns and solicited 
information regarding the ability of furniture stripping operations to 
comply with the proposed PELs through the use of engineering controls; 
human cancer risk from exposure to MC; and any applications of MC not 
addressed by OSHA's Preliminary Regulatory Impact Assessment. The 
Agency generated a considerable amount of information regarding these 
and other MC-related issues at public hearings (September 16-24, 1992 
and October 14-16, 1992) and in post-hearing comment periods that ended 
on March 15, 1993. OSHA subsequently received the materials covered by 
this notice.
    OSHA has determined that the above-mentioned information is 
relevant to full consideration of issues raised by the MC rulemaking. 
Therefore, OSHA is reopening the record to incorporate the pertinent 
materials and to allow the public an opportunity to comment.

DATES: Written comments on the materials incorporated through the 
notice of reopening must be postmarked by April 25, 1994.

ADDRESSES: Comments are to be submitted in quadruplicate to the Docket 
Office, Docket No. H-071A, U.S. Department of Labor, room N-2634, 200 
Constitution Avenue, NW., Washington, DC 20210. Telephone (202) 219-
7894. Written comments limited to 10 pages or less in length also may 
be transmitted by facsimile to (202) 219-5046, provided that the 
original and three copies are sent to the Docket Office thereafter.

FOR FURTHER INFORMATION CONTACT:
Mr. James F. Foster, Occupational Safety and Health Administration, 
U.S. Department of Labor, room N-3647, 200 Constitution Avenue, NW., 
Washington, DC 20210. Telephone (202) 219-8148.

SUPPLEMENTARY INFORMATION:

I. Background

    On November 7, 1991, OSHA issued a notice of proposed rulemaking 
(NPRM) (56 FR 57036) to address the significant risks of MC-induced 
health effects. The proposed rule required employers to reduce 
occupational exposure to MC and to institute ancillary measures, such 
as employee training and medical surveillance, for further protection 
of MC-exposed workers.
    OSHA convened public hearings in Washington, DC on September 16-24, 
1992 and in San Francisco, CA on October 14-16, 1992. The post-hearing 
period for the submission of additional briefs, arguments and 
summations ended on March 15, 1993.
    The Agency has subsequently obtained information which OSHA 
believes should be considered in the drafting of the final rule. 
Accordingly, the Agency is reopening the rulemaking record so the 
public has an opportunity to comment on that information. The materials 
being added to the record are discussed below.

A. Feasibility Analysis for the Furniture Stripping Sector

    OSHA conducted a Preliminary Regulatory Impact Analysis and 
preliminarily determined that it would be feasible for the furniture 
stripping sector to comply with the proposed standard of 25 ppm as an 
8-hour time-weighted average (TWA) permissible exposure limit (PEL) 
with a 125 ppm short-term exposure limit (as measured over 15 minutes) 
(STEL) and ancillary provisions (e.g., exposure monitoring, medical 
surveillance and training). Several commenters and hearing participants 
questioned the feasibility determination (Exs. 29, 30, 73 and 86). In 
response to issues raised during the hearings and comment periods, OSHA 
contracted with Mr. Richard Green to reexamine the technical and 
economic feasibility of the proposed rule for the furniture stripping 
industry. In order to give interested parties an opportunity to comment 
on this analysis, it is being introduced into the rulemaking record at 
this time.
    Mr. Green determined that the proposed standard would be 
technically and economically feasible for furniture refinishers. The 
cost of engineering controls and additional heating (of make-up air) 
needed to comply with the proposed rule were estimated to be 
approximately $300 per establishment per year. Total compliance costs 
would be higher than this figure and include costs for ancillary 
provisions, such as exposure monitoring, medical surveillance and 
training.
    Mr. Green determined the amount of ventilation that would be needed 
based upon the rate of evaporation of methylene chloride, principles of 
dilution ventilation, and estimates of costs for heating make-up air. 
Mr. Green's analysis utilized data in the MC docket and general 
reference materials such as the ACGIH Industrial Ventilation Manual for 
ventilation recommendations, and the 1993 Statistical Abstract of the 
United States to obtain monthly average, high and low temperatures.
    Based on theoretical and empirical models, Mr. Green determined 
that the average-sized firm will need to install an approximately 5,000 
cubic feet per minute (cfm) fan in both the stripping and rinse areas 
to ensure that the proposed PEL could be met in both areas. This would 
ensure good air mixing in both areas and provide adequate ventilation 
capacity. Mr. Green also recommended that the fans should be located 
near each process to provide a local spot ventilation effect.
    OSHA solicits comments on Mr. Green's analysis and the 
appropriateness of using this analysis as a basis for the Agency's 
final determination of feasibility in the furniture stripping sector.

B. National Cancer Institute Study on Methylene Chloride Exposure and 
the Risk of Developing Astrocytic Brain Cancer

    After the post-hearing comment period closed, OSHA received a copy 
of a study on the risk of developing brain cancer after exposure to 
chlorinated solvents conducted by researchers at the National Cancer 
Institute. This study was accepted for publication as two journal 
articles to be published in the American Journal of Industrial Medicine 
as ``Occupational exposure to chlorinated aliphatic hydrocarbons and 
risk of astrocytic brain cancer'' by Ellen F. Heineman et al. and 
``Occupational exposure to chlorinated aliphatic hydrocarbons: job 
exposure matrix'' by M.R. Gomez et al.
    The abstract for the Heineman et al. paper reads as follows,

    Chlorinated aliphatic hydrocarbons (CAHs) were evaluated as 
potential risk factors for astrocytic brain tumors. Job-exposure 
matrices for six individual CAHs and for the general class of 
organic solvents were applied to data from a case-control study of 
brain cancer among white men. The matrices indicated whether the 
CAHs were likely to have been used in each industry and occupation 
by decade (1920-1980), and provided estimates of probability and 
intensity of exposure for ``exposed'' industries and occupations. 
Cumulative exposure indices were calculated for each subject.
    Associations of astrocytic brain cancer were observed with 
likely exposure to carbon tetrachloride, methylene chloride, 
tetrachloroethylene, and trichloroethylene, but were strongest for 
methylene chloride. Exposure to chloroform or methy chloroform 
showed little indication of an association with brain cancer. Risk 
of astrocytic brain tumors increased with probability and average 
intensity of exposure, and with duration of employment in jobs 
considered exposed to methylene chloride, but not with a cumulative 
exposure score. These trends could not be explained by exposures to 
the other solvents.

    The Gomez et al. paper explains in detail the job-exposure matrix 
used to determine whether exposure to a particular solvent was likely 
for the subjects of the study. OSHA solicits comments on this study and 
its implications for the MC risk assessment.

C. Information Regarding the Use of Methylene Chloride as a Solvent in 
Adhesive Formulations in Flexible Foam Manufacturing

    During the rulemaking proceedings, OSHA solicited information on 
the feasibility of compliance with the proposed standard. After the 
post-hearing comment period had closed, the Center for Emissions 
Control sent OSHA materials with a cover letter from Mr. Stephen P. 
Risotto, detailing an ongoing analysis of adhesive use in foam 
manufacturing facilities and a request for OSHA to ``consider the 
inability of foam adhesive operations to meet the proposed occupational 
limits before issuing a final rule.'' The CEC submission also included 
a document entitled ``Foam Adhesive--Ventilation Project Description,'' 
which outlined the protocol for investigating potential engineering 
controls and feasibility for this sector, and a preliminary report 
entitled ``Foam Adhesive Fabrication Ventilation Study,'' conducted by 
Rust Engineering Company, which outlined recommendations to improve the 
ventilation systems for the spray booths, including costs of 
modifications.
    OSHA preliminarily determined that it was technologically and 
economically feasible for establishments that use adhesives to comply 
with the proposed standard or substitute away from MC. In this Federal 
Register notice, OSHA is soliciting comments on the submitted protocol 
and report and requesting information on the technological and economic 
feasibility of compliance with the proposed standard for adhesive use 
in this situation.

II. Public Participation

Comments

    Written comments regarding the materials incorporated into the 
methylene chloride rulemaking record through this notice must be 
postmarked by April 25, 1994. Four copies of these comments must be 
submitted to the Docket Office, Docket No. H-071A, U.S. Department of 
Labor, room N-2625, 200 Constitution Avenue, NW., Washington, DC 20210. 
(202) 219-7894. All materials submitted will be available for 
inspection and copying at the above address. Materials previously 
submitted to the Docket for this rulemaking need not be resubmitted.

III. Authority

    This document was prepared under the direction of Joseph A. Dear, 
Assistant Secretary of Labor for Occupational Safety and Health, U.S. 
Department of Labor, 200 Constitution Avenue, NW., Washington, DC 
20210.
    It is issued under section 6(b) of the Occupational Safety and 
Health Act (29 U.S.C. 655), and 29 CFR part 1911.

    Signed at Washington, DC, this 8th day of March 1994.
Joseph A. Dear,
Assistant Secretary of Labor.
[FR Doc. 94-5752 Filed 3-10-94; 8:45 am]
BILLING CODE 4510-26-M