664 HAZWOPER for General Site Workers V

Personal Monitoring

This requirement is based on the probability that significant exposure varies directly with distance from the source. If workers closest to the source are not significantly exposed, then other workers, presumably, are not significantly exposed and should not need to be monitored.

Personal air sampling is not necessary until site operations begin because occupational exposures are linked closely with active material handling. Thus, monitoring of those employees are likely to have the highest exposures to hazardous substances and health hazards is not required until the actual cleanup phase commences (e.g., when soils, surface waters, or containers are moved or disturbed).

• Personal monitoring samples should be collected in the breathing zone and, if workers are wearing respiratory protective equipment, outside the facepiece. These samples represent the actual inhalation exposure of workers who are not wearing respiratory protection and the potential exposure of workers who are wearing respirators.
• Sampling should occur frequently enough to characterize employee exposures.
• If an employee is exposed to concentrations over PELs, monitoring must continue to ensure the safety of all employees likely to be exposed to concentrations above those limits.

Personal monitoring may require the use of a variety of sampling media. Unfortunately, single workers cannot easily use multiple sampling media because of the added strain and because it is not usually possible to draw air through different sampling media using a single portable, battery-operated pump. Consequently, several days may be required to measure the exposure of a specific individual using each of the media. Alternatively, if workers are in teams, a different monitoring device can be assigned to each team member.

Another method is to place multiple sampling devices on pieces of heavy equipment. While these are not personal samples, they can be collected very close to the breathing zone of the heavy equipment operator and thus would be reasonably representative of personal exposures. These multi-media samples can yield as much information as several personal samples.

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