WASHINGTON — Federal regulators have moved to eliminate most uses of the industrial solvent trichloroethylene, or TCE, after years of research and advocacy warning that the chemical can raise the risk of Parkinson’s disease, including through contaminated groundwater that can reach drinking water supplies, Dec. 24, 2025.
The U.S. Environmental Protection Agency’s final rule, issued in December 2024, bans the manufacture, processing and distribution of TCE for most uses, while allowing limited, time-bound exemptions and phaseouts for certain industrial applications. The agency says the restrictions are designed to reduce serious health risks for workers and the public.
For readers trying to follow the policy paper trail, the rule is summarized on the EPA’s risk management page for TCE and published in full in the Federal Register notice for the final rule. Environmental groups that pressed for a ban have argued the move could prevent exposures that linger in communities for decades, including from legacy contamination at industrial sites.
What the science says about Parkinson’s disease and TCE
TCE has a long history as a metal degreaser and cleaning solvent. Because it can persist underground and migrate as vapor, it has been detected at contaminated sites and in groundwater plumes that threaten private wells and municipal systems.
Researchers have been warning about the potential link to Parkinson’s disease for more than a decade. A widely cited study of twins reported higher odds of Parkinson’s among those exposed to TCE and certain other solvents (see the 2012 analysis summarized on PubMed). In 2023, a large cohort study in JAMA Neurology found a substantially higher risk of Parkinson disease among veterans stationed at Camp Lejeune compared with veterans at a base without the same water contamination history. Also in 2023, neurologists and co-authors argued in a review that TCE may be an “invisible” and preventable contributor to rising Parkinson’s rates, calling for more research and policy action (full text).
Those older findings have gained new attention as advocates push prevention. The Michael J. Fox Foundation called the EPA action a turning point for the Parkinson’s community, saying the ban targets a chemical “known to increase risk,” in a Dec. 9, 2024, update on its site. In early 2025, the University of California, San Francisco described how research and public pressure converged behind the rule in a campus report. The Department of Veterans Affairs continues to track research on Camp Lejeune-related health outcomes, including Parkinson’s disease, on its public health research page.
What the EPA ban can — and can’t — do
Supporters say cutting off new uses of TCE matters because fresh releases today become tomorrow’s groundwater problems. But they also stress that a ban does not instantly erase decades of legacy contamination, especially in places where TCE has already seeped into soil and aquifers.
For families worried about Parkinson’s disease and environmental exposure, experts typically recommend checking local water quality reports, asking whether nearby sites have solvent contamination histories and considering certified filters if contaminants are detected. The bigger shift, researchers say, is upstream: reducing or eliminating the chemicals that can trigger disease in the first place.
The EPA rule is now the centerpiece of that prevention strategy — an attempt to ensure that fewer communities have to learn about TCE the hard way, after diagnoses of Parkinson’s disease begin to mount.
