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 https://www.osha.gov.

Jun 21, 1985

Mr. William R. Bunner
Manager Envirosafe Services, Inc.
115 Gibraltar Road
Horsham, Pennsylvania 19044

Dear Mr. Bunner:

I have been asked by Assistant Secretary Robert Rowland to reply to your letter of May 10, in which you requested information on allowable levels of hazardous chemicals on workplace surfaces and on the guidelines by which compliance with surface contaminant levels is enforced.

The Occupational Safety and Health Administration (OSHA) publishes its General Industry standards under Title 29 of the Code of Federal Regulations Part 1910(29 CFR 1910). Permissible exposure levels (PELs) for hazardous chemicals can be found in 29 CFR 1910, Subpart Z - Toxic and Hazardous Substances. A copy of the OSHA General Industry standards is enclosed for your information and use. Although some OSHA standards contain housekeeping provisions which address the issue of surface contamination, there are currently no surface contamination criteria or quantifications for skin absorption included in OSHA standards. The "skin" notation which appears with some of the chemical hazards listed in Table Z-1 of 29 CFR 1910.1000 merely indicates that on the basis of the best information available from industrial experience and from human and animal experimental data, certain substances have the potential to cause skin irritation and/or may contribute to overall exposure by the cutaneous route. This includes the mucous membranes and the eye, and may occur either by airborne exposure or by direct contact with the substance. The "skin" notation serves as a warning that skin contact with the substance can cause irritation and/or that cutaneous absorption should be prevented to avoid exceeding the PEL. Biological monitoring can be utilized for some substances to determine the relative contribution of dermal exposure to the total dose.

OSHA's Office of Health Compliance Assistance publishes an Industrial Hygiene Technical Manual (IHTM) as a part of OSHA's internal Instruction Directives System. The IHTM provides OSHA compliance officers with guidance on OSHA enforcement. It reflects current OSHA industrial hygiene practices and procedures. Chapter VIII of the IHTM treats the subject of sampling for surface contamination. Appendix A contains the Chemical Information Table, a compilation of information relevant to compliance with OSHA regulations for specified chemicals. Copies of those sections of the IHTM are enclosed for your information.

OSHA currently regulates airborne concentrations of chlorodiphenyls or polychlorinated biphenyls (PCBs) at PELs of 1 milligram per cubic meter of air (1 mg/m3) for chlorodiphenyls containing 42% chlorine and 0.5 mg/m3 for those containing 54% chlorine. While these PELs refer to airborne concentrations averaged over an 8-hour work shift (i.e., a time-weighted average concentration or TWA), and although there is no specific regulation of the levels of these contaminants on workplace surfaces, surface contamination will certainly contribute to airborne levels of these substances. Control of such surface contamination is one way to reduce their airborne concentrations.

In cooperation with OSHA, the National Institute for Occupational Safety and Health (NIOSH) publishes "Occupational Health Guidelines for Chemical Hazards" which contain a variety of industrial hygiene recommendations, toxicity data and other useful informtion on Federally-regulated chemicals. I have enclosed copies of the NIOSH/OSHA Occupational Health Guidelines for the PCBs mentioned above.

I hope this will be helpful to you.

If we can be of further assistance, please contact Ms. Gail Kleiner at the following address:

U.S. Department of Labor - OSHA
Room N-3657
200 Constitution Avenue, N.W.
Washington, D.C. 20210
Telephone: (202) 523-7505


Edward J. Baier
Directorate of Technical Support


May 10, 1985

Mr. Robert Rowland
Assistant Secretary of Labor
Occupational Safety & Health Administration
U. S. Department of Labor
200 Constitution Ave., N.W.
Washington, DC 20204

Dear Mr. Rowland:

I am writing to request a list of the allowable levels of hazardous chemicals on work place surfaces, such as floors.

Table 2-1 of 29 CFR 1910.1000 lists many chemicals, such as phenol, with a "skin" notation. These P.E.L. T.L.V.'s are, however, quantified for air and not for skin absorption.

In the interests of the safety and health of our employees in the hazardous waste clean-up and disposal business, it is essential that we know the criteria that establishes "surface P.E.L.'s (to coin a phrase)".

Although I am requesting your complete listing, my most urgent need is for the surface contamination criteria for polychlorinated biphenols (P.C.B's).

Additionally, I need to know the specific standards, laws, regulations, ordinances, guidelines, etc. by which compliance with these surface contaminant levels is enforced.

Thank you for your assistance in this matter. I will be looking forward to receiving this information.


Wm. R. Bunner, Manager
Safety & Training
Envirosafe Services, Inc.
115 Gibraltar Road
Horsham, PA 19044