In July, 2006, US EPA issued standards (40 CFR 63.322) that included the phase-out of perchloroethylene (also know as "perc", "PCE", or "Tetrachloroethylene") dry-cleaning solvent machines located in residential buildings by December 21, 2020.
After December 21, 2020, dry cleaners using perc machines located in residential buildings (co-residential) will be prohibited from using perc. Those dry cleaners located in residential buildings who are still using perc may switch to alternative cleaning methods such as wet cleaning, carbon dioxide or hydrocarbon technology. Co-residential perc cleaners may also choose to relocate the perc dry cleaning solvent machines to another facility that is not attached to any residential apartment or living spaces.
In the rulemaking, EPA notes that perc is an organic solvent of known human toxicity and reasoned that perc dry cleaners located in residential buildings posed the greatest risk to the general public.
Pennsylvania dry cleaners who are interested in reading the final rulemaking can find it here.