The Cal/OSHA Standards Board recently adopted a Permissible Exposure Limit (PEL) of 1 ppm for N-methylpyrrolidone (NMP). This PEL will be legally-enforceable throughout California. Because there is no Federal OSHA standard, the California PEL is likely to be, at the very least, inspirational throughout the United. States. Look for the minutes of the November 21 Standards Board on the Cal/OSHA website in mid-December.
The PEL process for NMP dates back at least 6 years. At the time, there was an active Health Experts Advisory Committee (HEAC). The members of the HEAC provided varying interpretations of animal exposure studies and of implications for the worker population. The exposure level for NMP recommended to the Standards Board was developed by one HEAC member who utilized a community risk analysis, one that includes sensitive populations. This community risk approach is used by OEHHA, which develops the Proposition 65 warnings required to be posted by California businesses. The 1 ppm level adopted by the Board is at the low end of exposure limits that have been adopted by other groups; and it’s one that is legally-enforceable (Kanegsberg, 2007).
California agencies face typical governmental budgetary and constraints. The last HEAC meeting was in mid-2012. It would be desirable for Cal/OSHA to reinstate the HEAC. In the absence of this active volunteer advisory system, it seems reasonable to predict that Cal/OSHA would utilize OEHHA to develop worker exposure limits and that these limits would tend to be lower than those developed by other agencies and professional organization.
More information
B. Kanegsberg, Cal/OSHA PEL Activities, NMP, Clean Source, December, 2007
https://bfksolutions.com/calosha-pel-activities-nmp/
Cal/OSHA site
http://www.dir.ca.gov/oshsb/Airborne_contaminants_N_-_Methylpyrrolidone.html
