Hidden Threat: Does the Common Chemical TCE Increase Your Risk of Parkinson's Disease?

For decades, scientists have sought to understand the complex causes of Parkinson's disease (PD), a neurological disorder that affects movement. While genetics play a role, environmental factors have long been suspected, and a groundbreaking study by researchers at Barrow Neurological Institute has shed new light on a potential culprit: Trichloroethylene (TCE). This chemical, a common industrial solvent used in various processes and products, has now been nationally associated with an increased risk of PD in Medicare beneficiaries.

This pioneering research suggests your proximity to these types of industrial facilities — especially in the rust belt area of the US — could be linked to a significantly greater risk of PD, confirming what decades of smaller studies have hinted at. Discover why this common chemical may be silently affecting your long-term brain health and what you can do about it.

The study, published in the Neurology Journal, found a nationwide, dose-dependent positive association between exposure to ambient (outdoor air) TCE and PD risk. This means that populations exposed to the highest levels of ambient TCE had a 10% greater risk of PD compared to those exposed to the lowest levels. This isn't entirely new; previous research has already shown that when inhaled or ingested, TCE readily crosses the blood-brain barrier and causes the type of damage—dopaminergic neurodegeneration—that leads to Parkinson’s. The prodromal symptoms of PD, which can include gait abnormalities and falls, were also found to be more common in cases living in neighborhoods with higher levels of ambient TCE.

A key strength of this research is its use of a large, population-based dataset focusing on new (incident) disease cases. The innovative geographic analysis allowed researchers to pinpoint areas where TCE exposure was highest. They found that ambient TCE exposure clustered primarily in the "rust belt" region of the United States, and the geographic distribution of high TCE levels partially overlaps with areas that also show a higher relative risk of PD, such as parts of the Midwest and Northeast.

The study also investigated areas surrounding specific, high-emitting TCE facilities. Most notably, in Lebanon, Oregon, the area with the greatest PD risk was located downwind (southeast) of a facility that emitted a massive amount of TCE in 2002. While the results point strongly to ambient TCE as a potential risk factor, the authors acknowledge that other environmental factors, like certain pesticides, likely also contribute to PD risk. Importantly, given the long period between exposure and diagnosis, the study focused on TCE estimates from 14–16 years before the incident PD diagnosis.

Read the full study: Ambient Trichloroethylene Exposure and Parkinson Disease Risk in Medicare Beneficiaries: Brittany Krzyzanowski https://orcid.org/0000-0002-4774-6120, Kassu Mehari Beyene https://orcid.org/0000-0002-2067-6054, Jay R. Turner https://orcid.org/0000-0001-7787-6244, and Brad A. Racette https://orcid.org/0000-0002-9582-8235Authors Info & Affiliations, October 21, 2025 issue 105 (8)
https://doi.org/10.1212/WNL.0000000000214174

Why Support Matters
A diagnosis of any form of Parkinson’s can feel overwhelming. But with the right support and resources, individuals can maintain independence, quality of life, and emotional well-being.
For resources, referrals, and support in navigating Parkinson’s and related conditions, contact the Parkinson’s Association of Southwest Florida at www.paswfl.org or call 239-417-3465.

For over 25 years, PASWFL has provided free, high-quality services and programs to individuals and families touched by Parkinson’s disease in Southwest Florida. Their goal is simple: help people live well with PD, regardless of where they are in their journey.
Each week, PASWFL offers more than 25 free programs and support groups, including:
Wellness and fitness classes
​Speech Exercise classes
​Educational seminars
Support for care partners
Support groups
There are no fees to become a member, and PASWFL welcomes anyone touched by PD.

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