More than17 million people in 41 U.S. states are exposed to the hazardous industrial chemical trichloroethylene, or TCE, in polluted drinking water.
TCE is a toxicvolatile organic compound, or VOC, that has been used since the 1920s to degrease metal parts and manufacture products. Improper disposal and industrial releases of TCE have contaminated public water systems and private wells.
In addition to water, TCE pollutes soil and air, exposingmillions of families. Even at very low levels, TCE can pose health risks, includingcancer,fetal heart defects andnervous system damage.
How TCE contaminates water sources
TCE makes its way into drinking water as a result of widespread industrial pollution. For decades, it has been used for cleaning, maintenance and manufacturing processes. Often, chemical waste from industrial facilities, like refineries, power plants and warehouses, was unsafely disposed of or spilled, impacting nearby communities.
While some industries have phased out TCE in favor of safer alternatives, its use continues in certain applications. In 2020, Minnesota became the first U.S. state to ban most uses of TCE, requiring businesses to transition to safer alternatives in 2022. The federal Environmental Protection Agency then issued a nationwide TCE ban in 2024 – but that is now under threat.
TCE can persist in groundwater for decades, posing a risk long after the original spill or dumping occurred. Environmental exposure to TCE leads to long-term contamination, threatening ecosystems and the availability of safe drinking water. Cleanup efforts to reverse the rapid spread of TCE through groundwater are complex andcostly.
While TCE in water is of concern, most people are exposed to TCE through air, as it is aVOC that easily evaporates at room temperature.
The most commonindoor exposures happen when TCE is present in household products like glues, adhesives, paint removers, spot cleaners and metal degreasers. TCE can also enter indoor air throughvapor intrusion, a process where chemical vapors from contaminated groundwater or soil seep into the building.
TCE can also get into the air when people use contaminated tap water for showering, cooking or cleaning, as it readily evaporates during these everyday activities. This can increase indoor air concentrations and contribute to overall exposure.
Communities near industrial sites, refineries, power plants and military bases are at particular risk for chronic TCE exposure, but contamination has been found in places far removed from obvious sources of pollution because TCE can travel long distances in groundwater.
National regulations for TCE in drinking water
TheEPA’s current limit on TCE in drinking water, known as amaximum contaminant level, or MCL, is5 parts per billion, or ppb. The agency set this standard decades ago and it doesn’t reflect today’s scientific understanding of TCE’s serious health risks. EWG recommends a much stricterhealth guideline of 0.4 ppb, based on updated research and health advisories from the state ofMinnesota.
The EPA's outdated MCL shows why legal limits on drinking water contaminants don’t always equal safe limits. Millions of people are legally exposed to TCE levels in their tap water that could harm their health, especially for pregnant women and children.
Unless and until the EPA updates its MCL for TCE, consumers must take their own steps to reduce exposure to this hazardous chemical.
Separate from the MCL, the EPA did take an important step in December 2024 bybanning most uses of the chemical. But some in Congress – Reps. Diana Harshbarger (R-Tenn.) and Mariannette Miller-Meeks (R-Iowa), along with Sen. John Kennedy (R-La.) – are pushing a resolution to undo this ban.
Check EWG’s Tap Water Database
For anyone concerned about whether TCE is in their drinking water, EWG’s Tap Water Database is a vital resource. As the largest publicly available tool for tracking contaminantslike TCE in drinking water nationwide, it allows anyone to search by ZIP code to see what’s in their water supply.
This year’s Tap Water Database update shows California, New York, Pennsylvania, Alabama and Wisconsinare among the states most affectedwith TCE. In California alone, more than 8.9 million people rely on utilities that have reported contamination.
Some utilities – likeFranklin Square in New York andMoorestown in New Jersey – reported average TCE levels nearly 10 times higher than EWG’s health guideline. In some areas, likeLoma Linda andEl Monte, both in California, TCE levels hover just below EPA’s MCL, but still far exceed what scientists consider safe for long-term consumption.
EWG’s interactiveTCE contamination map provides additional insights into areas at high risk of exposure.
What you can do
If TCE is detected in your water, there are ways to reduce exposure and protect your health.
To remove TCE from your tap water, look forcarbon-based filters certified to reduce VOCs or considerreverse osmosis systems. The Tap Water Database offers guidance on selecting the best filter for your specific location.
In areas with significant TCE contamination, a whole house filtration system may be necessary, along with mitigation measures to address vapors coming into homes from contaminated soil.
If you’re using well water, private testing is needed to check TCE levels since water utilities don’t monitor those sources.
Beyond your home, advocating for stronger protections – likemaintaining the EPA’s ban on TCE – and pushing for cleanup of landfills, industrial sites and military bases are critical steps toward reducing TCE pollution at its source and limiting peoples’ exposure.