Did you ever hear of the tragedy of the OSHA PEL's?
The current Permissible Exposure Limits for chemicals were issued in 1970, based on science of the 1950's. Since then OSHA, due to corporate lobbying and political influence, has not been able to update most of these limits.
For example, Toluene is a paint thinner, which has a PEL of 200 ppm. The current American Conference of Governmental Industrial Hygienists has a current recommended exposure limit of 20 ppm, which is over 10 times less than OSHA's.
Fortunately, the safety data sheets list these and other recommendations. Check Section 8 to see what the current recommended safe exposure limits are.