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.

December 23, 1992


                   REGION I



We apologize for the delay in this response. The following information is presented to you for your consideration and appropriate action.

The inspection, citations and resulting meetings and discussions with the Corps of Engineers concerning the Baird MaGuire site and the TSP-9 site specifically, has brought to the forefront the following issues concerning the application of the HAZWOPER standard.

First, how do the site characterization requirements from EPA CERCLA regulations interface with site monitoring requirements found in 1910.120(c), i.e. do areas at a hazardous waste site which do not require clean up require monitoring when invasive work is being performed?

When OSHA promulgated 1910.120 it purposely did not define the term hazardous waste site, deferring instead to EPA and other government agencies. Consequently areas defined as "clean", i.e. not needing remediation, by CERCLA would not fall under the scope of the HAZWOPER standard (assuming there is no potential for an emergency caused by a release of hazardous substance). However, areas that are clean within a larger hazardous waste site remediation project represent a special case. These sites may require ongoing compliance with the provisions of 1910.120, or they may not, depending on the potential for exposure. For example, if invasive work is being performed in an adjacent hot area there may be carry over to the clean area and hence exposure. If invasive work is being carried on in an area, previously characterized as clean, and conditions change e.g. a drum is uncovered, additional monitoring requirements would be invoked.

The second issue addresses the designation of hot, buffer and clean zones within a site. The designation of such areas is the responsibility of the employer and is expected to be made by competent individuals. Often times these designations are made on limited information, so larger territory would be designated than may be necessary. As more information becomes available on the extent and nature of the hazards on site, the size of the exclusion and buffer zones and the extent of the restrictions can be corrected accordingly.

It is our understanding that the TP-9 site at the Baird Maguire superfund site was initially characterized as clean per EPA CERCLA regulations. Invasive work was being undertaken in this area at which time suspicions as to the validity of the "clean" designation were raised. A reexamination of the site characterization data indicated potential exposures as high as 90% of the coal tar pitch permissible exposure level (PEL). Subsequently, an improved model of the exposure scenario was utilized which predicted a potential exposure of 4% of the PEL.

We see the timing of the reassessment of exposure relative to the time suspicions were raised about the validity of the initial characterization and the time between the two assessments of exposure as critical to determining if the citation issued to the Army Corps of Engineers should stand.

The Corps' position is that the two assessments were done as an integral part of the reassessment effort immediately following the questioning of the adequacy of the clean designation for the TP9 area.

If you have any questions or feel other issues need to be addressed in order to close out this case, please contact us.