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Land contaminant
Water pollutant

Perchloroethylene/tetrachloroethylene (PCE or Perc)

Perchloroethylene or tetrachloroethylene (PCE or Perc) is chlorinated solvent used in a variety of processes as a solvent and degreaser. When released in the environment, some PCE will evaporate while some will infiltrate into the ground and can make its way into groundwater. The chemical is toxic to humans at very low concentrations. In 2021, Minnesota banned the use of perchloroethylene for dry cleaning.


Perchloroethylene or tetrachloroethylene (PCE or Perc) is an organic chemical used in dry cleaning, as a solvent and degreaser, in auto paint and auto repair shops, and in some consumer products. PCE is resistant to degradation so can persist in the environment instead of breaking down eventually, like some other contaminants.

Due to the presence of one or more chlorine atoms in their structure, chlorinated solvents are heavier than water. Chlorinated solvents are also referred to as dense non-aqueous phase liquids (DNAPLs).

When PCE gets into groundwater, it can move off the property or area where the contamination occurred. Once in groundwater, PCE is capable of producing gas that rises up through soils and can get into nearby buildings, degrading indoor air quality. This is called vapor intrusion.

Human health and environmental concerns

The chemical is toxic to humans at very low concentrations. 

PCE has been found in soils and groundwater on many properties in Minnesota, particularly sites of dry cleaning businesses.

People may be exposed to PCE by inhaling it, absorbing it through the skin, or ingesting it. It can cause dizziness, headaches, liver and kidney damage in people who've had chronic exposure. Those exposed to high amounts of PCE may experience central nervous system damage, cancer, or death.

Monitoring, reporting, and regulations

In 2021, Minnesota passed a legislative ban on perchloroethylene for dry cleaning use. To give dry cleaners time to transition to the use of alternative solvents, the ban takes effect in 2026.