News Release USDL: 95-515
Monday, December 11, 1995
CONTACT: Frank Kane, (202) 219-8151
OSHA Extends Limited Reopening Of Methylene Chloride Rulemaking
Record Until Dec. 29
The Occupational Safety and Health Administration (OSHA)
announced it is extending until Dec. 29 its reopening of the
record on its proposed standard for methylene chloride (MC), a
probable human carcinogen widely used as an industrial solvent.
The proposed rule would reduce the permissible worker
exposure limit from the current 500 parts of MC per million parts
of air (500 ppm) to 25 ppm, averaged over eight hours. Ancillary
measures such as employee training and medical surveillance also
would be required. OSHA has estimated that the proposed rule
would reduce cancer risk by 95 percent for more than 185,000
OSHA's proposed MC risk assessment for cancer was based
primarily on extrapolation from mouse cancer bioassay data.
Considerable data are already available regarding this issue in
the rulemaking record.
On Oct. 24 OSHA reopened the rulemaking for 30 days with
comments limited to the subject of recently conducted studies
submitted by the Halogenated Solvents Industry Alliance (HSIA)
which assert that species differences in the enzymatic metabolism
of MC make the mouse a poor surrogate for estimating human cancer
risk. The use of the mouse data is a critical issue in the MC
rulemaking. The agency reopened the record to incorporate these
studies and to give the public an opportunity to comment on their
validity and on the appropriateness of the conclusions drawn by
The Oct. 24 notice generated substantial interest and the
agency is concerned that the initial 30 days was insufficient to
allow full participation by interested parties. Accordingly,
OSHA is reopening the comment period until Dec. 29, 1995.
Requests for copies of the HSIA studies should be addressed
to Christine Whittaker, Room N-3718, Health Standards Programs,
OSHA, U.S. Department of Labor, 200 Constitution Ave. NW,
Washington, DC 20210. Telephone: (202) 219-7174.
Fax: (202) 219-7125.
Written comments on the studies must be postmarked by Dec.
29, 1995, and submitted in quadruplicate to the OSHA Docket
Office, Docket No. H-071B, U.S. Department of Labor, Room N-2625,
200 Constitution Ave., NW, Washington, DC 20210. Phone: (202)
219-7894. All materials submitted will be available for
inspection and copying in the docket office. Materials
previously submitted to the docket for the rulemaking do not have
to be resubmitted.
Notice of the reopening appeared in the Dec. 6, 1995,