Because of the wide variety of APIs and dynamics of the pharmaceutical industry, there are very few defined regulatory or published health limits (such as PELs, RELs, TLVs, etc.) available.
This doesn’t mean you don’t need to worry about them, as they are regulated indirectly.
Employers are required to provide their employees with a place of employment that "is free from recognizable hazards that are causing or likely to cause death or serious harm to employees."
In the pharmaceutical industry, API Occupational Exposure Limits (OELs) are typically derived by the innovator during development, subject to refinement based upon toxicology and clinical testing.
While they aren’t typically published, they can sometimes be found on the manufacturers safety data sheets (SDS), or should be available from the commercial supplier of the material.
If you are having difficulty finding a limit, contact us to discuss options for having one developed.