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.

March 30, 1992


FROM:               PATRICIA K. CLARK,

SUBJECT:            Request for Technical Assistance Re:  Baird McQuire
                   Superfund Site

This is in response to your memorandum requesting a technical interpretation of 1910.120 as it applies to your inspection of the Baird & McQuire Superfund Cleanup site. Please accept our apology for the delay in this reply.

Your first and second questions ask whether 1910.120 is applicable based on soil sample results and exposure modeling. As you are aware, it is the responsibility of the employers of any workers at the site to ensure adequate site characterization. This is to be accomplished by competent individuals. As a result of this process, employers are able to designate contaminated (hot zones) and uncontaminated areas (low hazard areas where no special personal protective equipment is necessary). It is important to note that site characterization is a continuous process.

In this specific case, a citation was issued for lack of training under 1910.120(e) for workers who were in an area where exposure modeling indicated PAH exposures to be 90% of the PEL. If the employer was relying on the exposure model to make site characterization determinations then it would seem prudent to identify the areas where PAH exposures are 90% of the PEL as contaminated areas requiring 1910.120(e) training. For the purposes of the citation we do not see a need to evaluate the exposure model used since it was the one selected by the employer and there has been no allegations that it is not protective enough. The burden is on the employer to show that an area is "clean".

We plan to meet with the U.S. Corps of Engineers in Washington D.C. on April 9 (1:00 p.m.) to discuss exposure models, the use of the data from the models and the final issue raised in your letter. It would be helpful if someone from your Region familiar with these concerns could join us. Please contact MaryAnn Garrahan (FTS 523-8036) for further information.