Tetrachloroethylene in Indoor Air

March 12, 2026

1. What is Tetrachloroethylene?

Tetrachloroethylene, also known as perchloroethylene (PCE), is an organic chemical widely used in dry cleaning and metal degreasing, and also in the manufacture of other chemicals and consumer products. It is a non-flammable liquid at room temperature. It is volatile and has a pungent, sweet odor. Many people can smell it even when the air contains only one part per million of tetrachloroethylene. It is a colorless liquid with a characteristic odor. It decomposes upon contact with high-temperature surfaces or flames, producing hydrogen chloride, phosgene, and toxic, corrosive chlorine fumes. It decomposes slowly upon contact with moisture, producing trichloroacetic acid and hydrochloric acid. It reacts rapidly with metal powders, creating a fire and explosion hazard.

Tetrachloroethylene can decompose into other hazardous chemicals, such as trichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, and vinyl chloride.

2. How can one be exposed to tetrachloroethylene?

If a building is located near soil or groundwater contaminated with tetrachloroethylene, the tetrachloroethylene in the ground may seep into indoor spaces via vapor (see figure). When this occurs, exposure to tetrachloroethylene can occur through inhalation of indoor air.
Other sources of airborne tetrachloroethylene include: Emissions from facilities using tetrachloroethylene. Tetrachloroethylene fumes emitted from dry cleaning fabrics or consumer products such as adhesives, detergents, and car parts cleaners.

If tetrachloroethylene is present in household water, its vapors are released during showers.

3. How does tetrachloroethylene affect health?

Health effects depend on the dose, duration and frequency of exposure, and individual susceptibility. In contaminated sites, long-term health effects are often a concern and may include:

Changes in mood, memory, attention, reaction time, and vision.
Damage to the nervous system, liver, kidneys, and reproductive system.
Increased risk of cancers such as bladder cancer, non-Hodgkin’s lymphoma, or multiple myeloma.

Additionally, exposure to PCE during fetal development may increase the risk of health problems such as cleft lip and palate and neural tube defects (birth defects that affect the normal development of the brain, spinal cord, or spine).

4. How to reduce exposure to tetrachloroethylene?

PCE in the air: If your local health department notifies you that groundwater or soil in your area contains PCE, you may be at risk of exposure through vapor intrusion, which may require installing a contamination mitigation system.
PCE in water: Do not drink water known to contain PCE, and do not use it for cooking. Use alternative water sources (such as bottled water) until your drinking water is safe again. Shorten shower times and lower water temperatures to reduce the vaporization of PCE from contaminated water.
PCE in soil: If your local health department notifies you that there may be PCE contamination near your residence, minimize contact with soil and dust. Frequently wipe household items with a damp cloth or wet wipes to reduce indoor dust accumulation; remove shoes before entering the house and wipe pet paws; use an air purifier to reduce the risk of contaminant exposure. Do not allow children to get into the dirt and make sure they wash their hands after playing outside. If your yard has bare soil, cover it with a thick layer of grass or mulch.

5. What is a tetrachloroethylene screening level?

A screening level (SL) is a scientifically defined concentration, established by state regulatory agencies, that provides health protection and is used to assess the risk to human health from a contaminated site.
A screening level is an airborne concentration that should not pose a health risk to any population, including vulnerable groups such as children, pregnant women, and people with pre-existing health conditions.
A separate screening level is established to prevent a significant risk of cancer and adverse health effects other than cancer.
If the contaminant concentration is below the screening level, the site contamination is unlikely to pose an unacceptable health risk to humans.
If the contaminant concentration is above the screening level, regulatory agencies may need to conduct additional sampling and investigations, implement cleanup strategies, or take other measures to reduce human exposure to tetrachloroethylene contamination.