A new U.S. study has raised alarm over a common industrial chemical that may be quietly increasing the risk of Parkinson’s disease (PD) among older adults. Researchers have found that exposure to trichloroethylene (TCE)—a widely used solvent found in industrial degreasers, adhesives, and even contaminated groundwater—is linked to a higher likelihood of developing Parkinson’s.

The study, published in Neurology, examined more than 220,000 Medicare patients diagnosed with Parkinson’s disease between 2016 and 2018, comparing them with over 1.1 million healthy individuals of similar age and background. The researchers traced their residential exposure to TCE back in 2002, identifying regions where the chemical was more concentrated in the air.

Led by Dr. Brittany Krzyzanowski and her team at the Barrow Neurological Institute in Phoenix, the study revealed a dose-dependent relationship—meaning the higher the ambient TCE levels, the greater the risk of developing Parkinson’s. Those living in areas with the highest exposure faced about a 10 percent higher risk of the disease compared to those in areas with the lowest exposure.

The “rust belt” states and certain industrial zones across the U.S. were found to have the highest concentrations of TCE in the air, often near major manufacturing facilities. The study also observed a clear pattern: people living closer to these industrial sources were more likely to develop Parkinson’s, while the risk decreased with distance.

While the increased risk may seem small, the researchers emphasized that the widespread presence of TCE makes the potential health impact enormous. “The sheer number of people exposed to TCE in the environment means the potential public health impact could be substantial,” said Dr. Krzyzanowski. “This underscores the need for stronger regulations and more monitoring of industrial pollutants.”

TCE has long been under scrutiny for its toxic effects on the nervous system and potential to contaminate air and groundwater. However, this study is one of the largest to link long-term environmental exposure to the chemical with Parkinson’s disease at a population level.

Experts say the findings add to growing evidence that industrial pollution may be a hidden driver behind the global rise in neurological disorders. As Parkinson’s cases continue to surge worldwide, researchers are urging policymakers to strengthen environmental protections and phase out hazardous chemicals that silently endanger public health.