First, the potential impact of this chemical was studied in cosmetics, where it was formerly a common ingredient. Obviously, it makes so sense to have a reproductive toxin in cosmetics, and after a series of evaluations has been removed from most products. This summary is from the EU consumer product safety committee.
"Based on a worst case assessment with a maximum use concentration of 5% NMP in cosmetic products and a dermal absorption of 100%, the Margin of Safety is considered to be too low. There is an absence of specific information on the actual possible maximum concentrations of NMP present in cosmetic products and specific measurement of dermal absorption of it through skin at relevant concentrations.
With the information available at the time of assessment, the SCCS is of the opinion that the presence of NMP with a maximum use concentration of 5% in cosmetic products is not safe for the consumer. A re-evaluation may be possible should relevant data that addresses the above be provided"
Full Study Text
This spring the EPA released a study that concluded that even "gloves and respirators do not adequately reduce risks to people who use NMP for more than four hours per day on a single day or repeatedly over a succession of days." Additionally, they determined that "gloves made of butyl rubber or laminated polyethylene/EVOH are resistant to NMP." It seems NMP has long been prized for it's ability to premiate everything (paint and skin)to deliver other chemicals, and thus it can permiate all common glove materials (latex, PVC, and nitrile) within minutes.
The EPA was poised to act on this...
EPA Fact Sheet on N-Methylpyrilidone
... but guess what happened. All new actions have been frozen in the interest of reducing regulation and protecting businesses.
I guess protecting people is not so important.
Are there safe alternatives. Yes. Sand with a vacuum sander. Use a stripper based on
benzyl alcohol, which is listed as “generally accepted as safe in food” (tiny amounts). Dibasic esters (dimethyl succinate, dimethyl glutarate and dimethyl adipate) are also consideref safe. If you stay with NMP, Do Not Allow Women to Help. Effects on sperm are still up in the air, so if children are in your future, Don't Use NMP, or at least exercise extreme caution; butyl gloves, cartridge-style organic vapor respirator, waterproof coveralls.