WebMD, citing the National Academy of Sciences, reports that the toxin, <"https://www.yourlawyer.com/practice_areas/toxic_substances">PERC, is a so-called “likely human carcinogen.” Known as perchloroethylene or tetrachloroethylene, PERC is a commonly used dry cleaning solvent that can be found in routine use in about 85 percent of all United States dry cleaners, said WebMD. PERC is also used in the manufacture of other chemicals and can be used as a degreaser.
According to the Environmental Protection Agency (EPA), tetrachloroethylene can lead to negative neurological, liver, and kidney effects in humans following acute (short-term) and chronic (long-term) inhalation exposure. PERC exposure can also lead to adverse reproductive effects, such as spontaneous abortions.
WebMD reported that the EPA, in 2008, suggested the toxin be listed as a “likely human carcinogen,†and that its most serious noncancer toxicity is brain and nervous system damage. The EPA said that occupational exposure in dry cleaners suggested increased cancer risks, while laboratory studies also reported increased cancer risks in tests.
The EPA also suggested safe exposure levels be set that would be well below levels that cause these adverse effects; however, said WebMD, the
EPA did not finalize the ruling and, instead, asked the National Academy of Sciences to review it’s PERC risk analysis. The panel agreed with the EPA’s original findings and, said WebMD, noted that being a “likely human carcinogen,†means that despite a lack of “definitive†evidence, there is established proof of its dangers.
The National Academy also agreed that PERC’s most significant damage is to the neurological system and the brain, saying that drinking water and air quality levels must be set “well above†those levels that can cause these serious, negative effects, said WebMD.
“We praised the EPA for doing a very thorough job,” panel member Ivan Rusyn, MD, PhD, a toxicologist at the University of North Carolina, told WebMD. “The overwhelming opinion of the committee was that the EPA was correct.” The panel did agree that, perhaps, the EPA should strengthen how it evaluates studies, added WebMD.
The committee did find that the EPA focused too much on one study in determining safe levels, explained WebMD. It seems that the level in question is generally calculated by locating the highest PERC dose that does not cause harm and then dividing that dose by 1,000, or more, said WebMD. Using its mathematics, the EPA then suggested that a safe concentration for the toxin be two parts per billion (ppb); however, the Academy utilized a number of different studies and came up with more conservative levels of between six and 50 ppb.
The Academy only ruled on the EPA’s science and did not offer advice on policy for industry’s use of PERC, saying that policy needs to be determined by the EPA, individual states, and congress, according to WebMD. Of note, California implemented a law in 2007 to outlaw PERC use there by 2023 that also requires a ban on dry cleaning machines that are older than 15 years by July 1 of this year, said WebMD. Also, as of this July, PERC machines will not be allowed in buildings in which California residents live, added WebMD.
