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. |
September 3, 1996
MEMORANDUM FOR: |
REGIONAL ADMINISTRATORS STATE DESIGNEES
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FROM: |
JOHN B MILES, JR., DIRECTOR DIRECTORATE OF COMPLIANCE PROGRAMS
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SUBJECT: |
PEL for Inorganic Mercury |
The purpose of this memorandum is to address the
permissible exposure limit (PEL) for mercury. As you may know,
Table Z-2 of 29 CFR 1910.1000 incorrectly lists the inorganic
mercury PEL as a ceiling value of 1 mg/10m3 (0.1
mg/m3). It has come to our attention that compliance
officers may be citing workplace mercury exposure as a ceiling
PEL rather than as an 8-hour time weighted average (TWA).
While this error has not been corrected in Table Z-2 of 29 CFR
1910.1000, OSHA originally issued a correction notice in the old
Field Operations Manual. Enclosed for your use and information is
a [June 30, 1976 letter of interpretation] and a copy of the October 30, 1978 ["Inorganic Mercury and its Compounds" [CPL 02-02-006 (formerly CPL 2-2.6)] directive] which provides documentation for the 8-hour TWA mercury PEL as opposed to a ceiling value.
Please assure that all field personnel receive a copy of this
memorandum and when a mercury over-exposure is cited, it is cited
as an 8-hour TWA PEL. If you have any questions please contact
the [Office of Health Enforcement at 202 693-2190].
[Corrected 6/2/2005]
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