CAL/OSHA is considering setting the worker permissible exposure limits (PEL) for n-methyl pyrollidone (NMP) to a low level. These are considerations, not final decisions. We’re not screaming NMP in a crowded theater; or shouting that “the PEL’s are falling.” However, we think you should be aware of and follow the CAL/OSHA activities, because NMP is used in a number of diverse industrial applications, NMP is being considered as a replacement for Hazardous Air Pollutants (HAPs) in many pollution prevention and sustainable process efforts. Cal/OSHA can set PEL’s that are enforceable throughout California; it is reasonable to expect that California PEL’s may influence activities throughout the United States.
Adding to available PEL’s
California is working to set state-wide PEL’s, particularly where Federal OSHA has not set worker exposure levels. According to a document issued by the California Hazard Evaluation System & Information Service (HESIS), a department of the California Department of Health Services (DHS), the only existing US exposure guideline for NMP is an 8-hr Time Weighted Average (TWA) of 10ppm, recommended by the American Industrial Hygiene Association’s Workplace Environmental Exposure Level (WEEL) committee. NMP eight-hour exposure limits set by 14 other countries range from 1 ppm to 100 ppm.
Analysis, 1 ppm PEL, TLV for NMP
In a report and analysis of NMP prepared by Julia Quint and presented at the November 2, 2007 meeting of the Health Expert Advisory Committee (HEAC) that is tasked by Cal/OSHA to recommend PEL values, the recommendation was for a PEL of 1 ppm (TWA) with a skin notation and required biological monitoring. The recommendation is based in part on analysis and community risk assessment by the Office of Environmental Health Hazard Assessment (OEHHA); and the 10-fold uncertainty factor used to develop the number includes an allowance to protect sensitive population. OEHHA is perhaps most familiar to you as developing the list used for the Proposition 65 warnings posted in businesses and public places throughout California.
It is our understanding that the 1 ppm recommendation is just that – a recommendation. We would expect to see discussions at one additional meeting of the HEAC; and there are additional steps to the PEL process.
It is to the credit of Cal/OSHA that the newly-developed PEL process is transparent and that report templates will make the process somewhat standardized. The NMP report is publicly available and downloadable at the DOSH website. Please note that California Department of Occupational Safety and Health (DOSH) is often referred to as Cal/OSHA.
http://www.dir.ca.gov/dosh/DoshReg/5155Meetings.htm
Additional chemicals; upcoming HEAC meeting
In addition to NMP, other compounds scheduled for near-term consideration include dichloroacetic acid, hydrogen fluoride, and hydrogen chloride.
The next meeting of the HEAC is scheduled for January 29, 2008, in Oakland, CA. The tentative agenda includes toluene, trichloroethylene, carbon disulfide, and sulfuric acid.
More about the Cal/OSHA PEL Process
The recently-unveiled Cal/OSHA PEL process has the potential for efficiency, standardization, and transparency. Toxicological issues tend to be complex. Since the California PEL’s may impact your operation and your workers, you will find it productive to learn more about the process and perhaps to provide input.
Additional information about the development of the Cal/OSHA PEL process and comparisons of approaches used for worker and community safety can be found in “Green Files,” the newsletter of the Surface Quality Resource Center (SQRC), volume II, Issues 1 – 3, 2007.
http://www.sqrc.org/Newsletter%201/Newsletter%20page.html
