An all too common response investigators make to an impending occupational exposure problem is "let's get some pumps and media and start sampling." Getting the most for your air sampling dollar depends to a large extent on knowing in advance of the actual sampling exactly what you are going to sample for, and the most effective overall sampling strategy. In most cases, there are a number of readily available tools that allow you to make these determinations well before the actual sampling is started.
Probably the most effective and most often neglected tool is the Material Safety Data Sheet or MSDS. Under the provisions of the Hazard Communications Standard, employers are responsible for informing employees of the identities and hazards of chemicals found in the workplace. Manufacturers who supply chemicals used in the manufacturing process are required to supply MSDS for all of the hazardous chemicals they distribute. These sheets should be kept on file and made available to supervisors and workers. They contain much valuable information regarding potential for exposure as well as other valuable information including:
Product name, chemical name, CAS#
Incompatibilities
Hazardous ingredients and exposure limits
Required Personal Protective Equipment (PPE)
Health Hazards
Exposure symptoms: Chemical Routes of Entry
Fire, explosion and reactivity hazards
Manufacturer
Precautions for safe handling, storage and use
Chemical characteristics
Disposal methods
Spill or leak procedures
Transportation Requirements
Regulatory reporting requirements
First aid procedures
Old exposure reports should be kept on file. If these reports can be located, they can provide valuable information about chemicals that were sampled for in the past. If manufacturing conditions have not changed, they can identify not only chemicals that need to monitored, but the methods and even the laboratories that can be used for the current analysis.
Most manufacturing facilities are required to keep chemical inventories. These inventories can be used to pinpoint not only chemicals in use but also the amounts that are being used. This data can be used to estimate the potential for exposure as well as the identity of the chemical involved.
If all of the above mentioned steps fail, what is the next option? If exact chemical(s) involved can not be identified it should at least be possible to identify the general class. Are they organics, acids, amines, metals, PNAs, aldehydes, or isocyanates? If a general identification can be made, there are a number of chemical exposure profiles that can be very useful to verify the exact nature of the exposure. Here are some of these profiles and the OSHA or NIOSH methods:
Organic Vapors - OSHA PV2120 GS/MS
Organic Vapors - OSHA 7 GC/FID
Inorganic Acids - NIOSH 7903
Aldehydes - NIOSH 2016
Isocyanate Profile - OSHA 42, 47
Polynuclear Aromatics - NIOSH 5506