National Clothesline 

HSIA asks EPA to add nPB to

hazardous air pollutants list 

The Halogenated Solvents Industry Alliance has petitioned EPA to list n-propyl bromide 

(nPB) as a hazardous air pollutant under Section 122 of the Clean Air Act. 

The listing would result in regulation of significant sources of nPB, HSIA said. 

HSIA, which represents manufacturers of manufacturers, producers, distributors and 

commercial users of perchloroethylene and other halogenated solvents, noted that nPB is 

being marketed as an ‘unregulated’ alternative to chlorinated solvents in a variety of 

applications. 

“Chlorinated solvents are listed as hazardous air pollutants and industrial sources of 

chlorinated solvent emissions are stringently regulated,” HSIA said in its petition. “NPB is 

being aggressively marketed as an unregulated alternative to chlorinated solvents. Indeed 

sales literature for nPB emphasized that is it essentially unregulated.”

As a drycleaning solvent, nPB is sold under the trade names DrySolv and Fabrisolv. 

Responding to the increasing usage of nPB, the Occupational Safety and Health 

Administration nominated nPB for further study in the National Toxicology Program. HSIA 

cited the NTP study, recently submitted for peer review, that concluded there was clear 

evidence for carcinogenicity in female rats and mice exposed to nPB. 

HSIA also noted that observations in one group of workers suggested the signs of 

neurotoxicity are detectable at levels of one to five parts per million in air exposure averaged 

over eight hours 

“Observations of the toxic effects of nPB in animals and workers exposed to it demonstrate 

that exposed populations, whether workers or the general population, may face serious 

health effects which could include neurological effects, cancer and reproductive effects,” HSIA 

said. 

According to the petition, global production of nPB has been growing and was estimated at 

20,000 to 30,000 metric tons in 2007. China is among the leading producers with about 

20,000 metric tons in 2008 of which approximately 40 percent was exported. 

Use of the solvent in the United States was reported at 5,000 metric tons and growing at a 

rate of 15 to 20 percent a year. 

The petition also cited a study on the use of nPB in New Jersey drycleaning plants which 

noted that “some green or organic solvents in the drycleaning industry intended to replace 

perc may result in significant exposures above acceptable guidelines among some workers.”

The study found exposures to nPB in two of three shops measured that were greater than 

the American Conference of Governmental Industrial Hygienists threshold limit value of 10 

parts per million for nPB. The highest exposure recorded was 54 ppm. 

“Many drycleaning operators may not realize that the machine components and settings 

must be changed when converting from perc to nPB,” the study reported. “Not performing 

these modifications may result in overheating and significant leaks in the drycleaning 

equipment.”

The elevated exposures may have resulted from leaks due to normal machine wear over 

time, ineffective maintenance, and from the incompatibility of nPB with gasket materials, the 

study said. 

“Careful consideration and study of potential exposures and health effects among workers 

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using new chemicals or processes must precede any regulatory attempt to facilitate 

substitution for environmental purposes,” the report said. 

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