Employers are required to limit employee workplace chemical exposures to non-hazardous levels. Exposures by skin absorption or ingestion are easily to recognized and prevented (see Personal Protective Equipment). The evaluation of inhalation hazards is more difficult. Air monitoring is needed to determine the employee exposure level to individual hazardous chemicals.
The factors in determining airborne chemical exposure are: type of contact, length of contact, and chemical concentration. The purpose of an air monitoring program is to confirm whether specific hazardous chemicals are present and to determine if the concentration presents a hazard.
The regulation OSHA 1910.1000 (which dealing with air contaminants) requires employers to limit airborne exposure to hundreds of hazardous chemicals. Chemical specific regulations like those for formaldehyde, asbestos, and lead commonly require employers to provide routine monitoring of airborne concentrations.
Hazard Identification All hazardous chemicals present in the workplace must be identified. Information available for these chemicals is evaluated for potential exposures hazards.
Monitoring Method - Monitoring methods vary in their accuracy and specificity. They are primarily determined by the physical form and exposure route of the chemical to be evaluated. Simple screening methods can be used to quickly determine if a hazardous chemical is present or not. Direct reading instruments may provide adequate monitoring in some cases. The need for a more accurate determination of concentration often requires collecting a sample of the air contaminant and sending it to an analytical laboratory. Multiple samples may be necessary to statistically determine exposure concentration.
Analytical Method - The method used must be accurate, sensitive, specific, and reproducible. The analysis method is dependent on the chemical and the capability of the laboratory. Usually the analytical method determines sampling method. When available, standard methods of analysis developed by NIOSH, OSHA, or the EPA are used.
Interpreting Results - The significance of results depends upon accuracy and the recommended exposure limit. Possible interpretations of monitoring results may be:
- hazardous chemical was not detected;
- no hazardous concentrations were detected; and
- hazardous concentrations were detected.
Response Action - Response action taken as a result of monitoring is dependent on the interpretation of the results. Possible response actions include:
- no response required;
- additional sampling required;
- temporary protective measures required while additional sampling is performed; and
- temporary protective measures required while permanent corrective measures are developed and implemented.
Departments are required to maintain records of all their chemical monitoring and to provide the results to all affected employees.