Quick answer
Perchloroethylene (perc, or PCE) is the solvent most dry cleaners around the world have used for decades. The US Environmental Protection Agency classifies it as likely to be carcinogenic to humans, the WHO cancer agency lists it as probably carcinogenic, and it can contaminate air, soil and groundwater. Swan Clean does not use perc: our dry cleaning is Green Earth Cleaning certified and uses a silicone-based solvent instead.
Key takeaways
- Perc is a chlorinated solvent that cleans well but raises health and environmental concerns.
- The US EPA classifies perc as likely to be carcinogenic to humans, and the IARC places it in Group 2A, probably carcinogenic.
- Workers face the highest exposure, but residues can remain in garments that are not fully dried and aired.
- Several regulators are phasing perc out of dry cleaning; the US EPA finalised a phase-out in 2024.
- Swan Clean uses Green Earth Cleaning, a silicone-based process, instead of perc.
What is perc?
Perchloroethylene, also called tetrachloroethylene, PCE or simply perc, is a colourless chlorinated solvent. It dissolves grease and oil very well and does not burn easily, which is why it became the standard dry cleaning solvent in the twentieth century. The sweet, chemical smell many people associate with freshly dry-cleaned clothes often comes from perc.
Why regulators are concerned
- Cancer classification. The US Environmental Protection Agency classifies perc as likely to be carcinogenic to humans, and the International Agency for Research on Cancer (IARC) places it in Group 2A, probably carcinogenic to humans.
- Short-term effects. Breathing perc vapour can cause headaches, dizziness and irritation of the eyes, nose and throat. Dry cleaning workers have the highest exposure.
- Environment. Spills and poor disposal have contaminated soil and groundwater near dry cleaning shops in many countries, and clean-up is slow and expensive.
- Phase-outs. California phased perc out of dry cleaning, and in 2024 the US EPA finalised a rule to phase it out of dry cleaning nationwide over the coming years.
Can perc stay in your clothes?
Garments that are not fully dried and aired before packing can hold small amounts of solvent, especially thick fabrics such as wool, polyester and padding. That is one reason a strong chemical smell on a garment is a sign to air it outdoors before wearing or storing it, and a reason we prefer solvents that are odour-free by design.
How Swan Clean does it differently
Our dry cleaning at the Sector 82, Mohali plant is Green Earth Cleaning certified. The process uses a liquid silicone solvent instead of perc or petroleum. It is gentle on fabrics and embellishments, and garments come back without a chemical odour. Laundry runs on Diversey chemistry that is Ecocert certified and dermatologically tested by Dermatest.
Read how the main solvents compare in our guide to Green Earth, perc, MTO and hydrocarbon.
Questions to ask any dry cleaner
- Which solvent do you use: perc, petroleum (MTO or hydrocarbon) or silicone?
- Is the solvent filtered and distilled between loads?
- Are garments fully dried before packing?
- Is the cleaning done in your own plant, or sent to a third party?
