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• Standard Number: 1910.1052


OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.gov.


November 20, 1998

MEMORANDUM TO: Regional Administrators

FROM: Richard E. Fairfax, Acting Director
Directorate of Compliance Programs

SUBJECT: Amendments to Methylene Chloride Standard
(29 CFR 1910.1052).


As you are aware on September 22 1998, the Occupational Safety and Health Administration (OSHA) published, in the Federal Register, amendments to the standard for regulating occupational exposure to methylene chloride (29 CFR 1910.1052). The amendments are a result of a requested motion for reconsideration filed by the International Union, United Automobile, Aerospace and Agricultural Implement Workers of America (UAW), the Halogenated Solvents Industry Alliance, Inc., and others. The amendments:

  • Modify the medical surveillance provisions to incorporate temporary medical removal protection (MRP). The temporary MRP is accorded employees who are removed or transferred to another job because of a medical determination that exposure to methylene chloride may aggravate or contribute to the employee's existing skin, heart, liver, or neurological disease. The compliance date for the new MRP provisions was October 22, 1998, for all employers.

  • Change the startup dates by which employers of specified sizes in certain identified application groups, i.e., who use methylene chloride in certain work operations, (1) must use respirators to protect employees exposed above the 8-hour time-weighted-average (TWA) permissible exposure limit (PEL) and (2) must have instituted feasible engineering controls for achieving the short-term exposure limit (STEL) and 8-hour TWA PEL. A table providing startup dates for all provisions of the standard for all employers is attached to this memorandum.

  • Require employers who have been granted a time extension for implementing engineering controls and respiratory protection in order to achieve the 8-hour TWA PEL, and who have done exposure monitoring indicating that the STEL is not exceeded, to nonetheless continue to monitor the STEL exposures at 3-month intervals until they have implemented such engineering controls and/or respiratory protection. The startup date for these employers to resume STEL exposure monitoring was October 22, 1998.

Since the MRP requirements and the alteration to the STEL monitoring requirement are now in effect, compliance officers will need to review them prior to performing future inspections involving methylene chloride. Although the MRP provisions are similar to those contained in the Inorganic Lead Standard, 29 CFR 1910.1025, they require a close review. The methylene chloride compliance directive, CPL 2-2.68, is being updated to cover and explain in further detail these amendments. For the present, if there are questions about enforcing the amendments, please contact OSHA's [Office of Health Enforcement] at (202) 693-2190.

[Corrected 4/20/2009]


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