Where is Trichloroethylene Found?


Course: SS4561
CE Original Date: 08/05/2022
CE Expiration Date: 08/05/2024
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Learning Objective 1 (cont.)

After completing this section, you will be able to define sources of TCE exposure.


Numerous people living in the United States are or have been exposed to TCE because of its widespread presence from past and current uses. In addition to occupational exposure of workers in industries using TCE, the general population can be exposed to TCE in ambient air, drinking water supplies, certain consumer products, and contaminated foods (ATSDR, 2019; EPA, 2011c; NTP, 2016).

In general, atmospheric levels are highest in areas of concentrated industry and population and lower in rural and remote regions. Mean TCE concentrations measured in air at locations across the United States are generally between 0.01 ppb and 0.3 ppb, although mean levels as high as 3.4 ppb have been reported (EPA 2011a).

Workers, particularly in the degreasing industry, are exposed by inhalation to the highest levels of TCE. Based on monitoring surveys, these workers might be exposed to levels ranging from approximately 1 ppm to 100 ppm.

The general population can also be exposed to TCE by contact with or consumption of water from supplies contaminated with the chemical, by consumption of contaminated foods, and by contact with consumer products containing the compound.

Between 4.5% and 18% of the drinking water supply sources in the United States that are tested on a yearly basis by EPA have some TCE contamination. Levels are typically <30 ppb. TCE levels in the low parts per billion range have been measured in food; however, levels as high as 140 ppb were measured in a few samples. Note that the amount of TCE found by chemical analysis is not necessarily the amount that is bioavailable (ATSDR 2019).

Occupational Sources

Occupational exposures can occur in chemical industries that manufacture

  • pentachloroethane,
  • polyvinyl chloride, and
  • other polychlorinated aliphatic hydrocarbons, flame retardant chemicals, and insecticides where TCE is a chemical intermediate.

Other potential exposures occur in the manufacturing processes of

  • disinfectants
  • dyes
  • perfumes
  • pharmaceuticals
  • soaps

The following occupations also have increased likelihood of exposure

  • dry cleaners
  • mechanics
  • oil processors
  • printers
  • resin workers
  • rubber cementers
  • shoemakers
  • textile and fabric cleaners
  • varnish workers
  • workers reducing nicotine in tobacco
Environmental Sources

TCE can be released to air, water, and soil at places where it is produced or used.


TCE is widely detected in ambient air. EPA reports the annual mean concentrations of TCE measured at approximately 300 locations across the United States between 1998 and 2008. Annual mean TCE concentrations at most of these locations were between 0.01 ppb and 0.3 ppb. Some locations had annual mean levels as high as 0.7–3.4 ppb (ATSDR, 2019; EPA, 2011a).


TCE is a common groundwater and drinking water contaminant. TCE has been detected in many samples taken from drinking water supplied by

contaminated sources from which TCE and other volatile organic compounds are not always completely removed by conventional water treatment. EPA (EPA, 2011b) conducts yearly monitoring of

the concentrations of TCE in public water systems located across the United States. During 2005, TCE was detected in 2,292 out of 46,937 samples (4.9%) collected from groundwater-supplied systems and 1,874 out of 12,705 samples (14.8%) collected from surface-water supplied systems (ATSDR, 2019).

Because of TCE’s volatility, household activities such as bathing, laundering, and cooking with contaminated water can produce TCE air concentrations above ambient levels.


Natural and processed foods can contain TCE because of direct uptake through the environment, contamination of water used in food processing, and contamination by solvents used in cleaning food processing equipment. TCE was detected in 30 table-ready food items collected from supermarkets across the United States during a 5-year study (1996–2000) conducted by the U.S. Food and Drug Administration (FDA) (Fleming-Jones ME, 2003).


TCE can be released into the soil through industrial discharges into surface waters and through landfill leachate (ATSDR, 2019).

Sources from Consumer Products

TCE has been listed as a major ingredient in several consumer products, such as

  • degreasers intended for use in automotive products,
  • adhesives,
  • cleaning fluids for rugs,
  • paint removers/strippers,
  • spot removers, and
  • typewriter correction fluids.
Key Point
  • Numerous people living in the United States have been or are being exposed to TCE because of its widespread presence from past and current uses.
Section 1.2 Question #1

To review relevant content, see “Environmental sources” in Section 1.2.

Page last reviewed: September 9, 2022