2. The chemicals of most concern (i.e., most toxic, most used, most complaints received) must be evaluated.
3. Working conditions during the sampling should be:
4. Most air samples collected should be from the worker's breathing zone - not of the general room air - and for the full shift of work (including overtime).
5. For OSHA, required time-weighted average samples must be collected for the full work shift (typically eight hours). (It pays to remind OSHA to adjust for overtime when they inspect.)
6. If there are short-term or peak exposures, then special sampling to evaluate these conditions needs to be conducted.
7. The possibility of skin absorption and ingestion (from chemical contamination of surfaces which come into contact with hands) must be evaluated.
8. If workers are working overtime, this must be considered when conducting sampling. Sampling results must be adjusted accordingly.
9. If exposures are to chemical mixtures, be sure that all components are sampled for or are otherwise factored into the evaluation.
10. Sampling should be done for the same chemical, under fairly similar working conditions, but at varying times, shifts, etc., to ensure accuracy and representativeness.
11. To get an accurate and representative time-weighted average (TWA) for a particular chemical exposure, sampling must be done over a number of shifts, not just one or two.
12. There may be seasonal variations in exposures, so sampling should also be done at different times of the year in order to take this variation into account.
13. When conducting a survey, the company should monitor either the highest risk workers or all workers, but not just the workers with the lowest risk of exposure. Under the OSHA Access Standard 1910.20, workers have a right to all monitoring data. Request it routinely.
14. Evaluate whether or not the exposure standards being used by the company are the strictest OSHA or NIOSH levels available.
16. Is the correct sampling method being used for a specific contaminant? NIOSH has standardized protocols for sample collection and analysis. If the wrong method is used, then the results will be inaccurate.
17. All pumps must be checked and calibrated for accuracy prior to and after sampling. Obtain records for this along with the name of the person conducting the sampling.
18. Make sure the union or the union representative has the right to observe the sampling.
Summary written by Jerry Roseman, Industrial Hygienist.