Pollution Prevention in Paint Stripping & Removal
Paint strippers have a tough job to do, and therefore, many ingredients and formulations pose potentially harmful impacts to human health. Two ingredients in particular, methylene chloride (or dichloromethane – DCM) and N-methyl-2-pyrrolidone (or 1-methyl-2-pyrrolidone NMP), have been historically used in common paint stripping formulations. Both are on the EPA’s Toxic Substances Control Act’s (TSCA) ten priority chemicals to be analyzed for risks posed to workers and the general public. Both are also on California’s Prop 65 list, DCM for carcinogenicity, and NMP for developmental toxicity.
Both exhibit these and other human health impacts, but DCM has been linked to more than 60 deaths nationwide since 1980. Many deaths caused by DCM resulted from acute inhalation exposure in confined or poorly ventilated spaces, such as bathtub refinishing, or boat cabin interior refinishing, but unfortunate exposures in industrial settings have also contributed.
In May 2019, EPA finalized a regulation covering DCM in consumer paint stripping and paint removal products prohibiting the manufacture, processing, distribution, and sale by retailers (at stores or online). The ban went into effect in November 2019. To be considered a distributor and not a retailer, the entity can only supply DCM paint and coating removal product to commercial or industrial end users or businesses.
In 2020, PPRC conducted a review of 22 paint stripper/remover product formulations in a high level assessment of hazards of the active ingredients. All formulations were gleaned from safety data sheets (SDS) accessed online. A comparison of potential human health hazards is presented in the report, Paint Stripping/Removal Chemicals and Alternatives.
Specific ingredients of higher concern identified in some products included: DCM, NMP, ethylbenzene, methanol, naphthalene, dimethylformamide, naphtha, toluene xylene, and 2-butoxyethanol.
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Specific ingredients exhibiting potentially lower health hazards included: benzyl alcohol, dimethyl adipate and dimethyl gluterate (dibasic esters), diethylene glycol mono-N-butyl ether and dipropylene glycol monomethyl ether (glycol ethers), dimethyl sulfoxide (DMSO)** various alkalines, methyl ester (soybean oil), and alcohols, c11-14, ethoxylated.
**Note that DMSO is fairly low in toxicity itself, but is very strong skin penetrant and expediently reaches the bloodstream. Depending on the toxicity of other ingredients combined in a DMSO formulation, it can contribute to high risk by carrying other chemicals into the bloodstream
Efficacy of alternative formulations was not assessed in the above research, however, PPRC conducted a few efficacy trials in 2019, on auto and aerospace coatings. Discussions of performance of the different formulations, along with photos are available.
• Paint Stripping Formulations for Aerospace Coatings Methylene Chloride-Free and NMP-Free
These projects were developed under Assistance Agreement No. X9-01J34101 awarded by the United States Environmental Protection Agency (EPA), and has not been formally reviewed by EPA. The views expressed are solely those of PPRC.