A widely used industrial cleaning chemical is raising growing concern among scientists, who warn it may be linked to a sharp increase in cases of Parkinson’s disease.

The substance, trichloroethylene (TCE), has been used for more than a century in applications such as metal degreasing, dry cleaning and even coffee decaffeination. Although its use has declined in recent years, its environmental footprint remains significant.

Widespread contamination and hidden exposure

Researchers say TCE has spread extensively into groundwater, air and soil, creating long-lasting pollution. In some areas, contamination has formed underground plumes stretching for miles, affecting drinking water sources.

The chemical can also evaporate and enter buildings through a process known as vapor intrusion, meaning people may be exposed simply by living or working above contaminated ground—often without realizing it.

Unlike other environmental hazards, routine testing for TCE is not consistently carried out, raising concerns about undetected exposure affecting large populations.

Health risks and neurological impact

TCE is already classified as a carcinogen and has been linked to miscarriages and congenital heart defects. However, new research suggests its neurological impact may be even more alarming.

Studies indicate that exposure to TCE may increase the risk of developing Parkinson’s disease by up to five times. Scientists believe the chemical can enter the brain and damage mitochondria—the structures responsible for producing energy in cells—particularly in neurons that produce dopamine.

The loss of these cells is a defining feature of Parkinson’s disease.

Further research also points to the activation of biological pathways associated with the condition, suggesting a link between environmental exposure and genetic susceptibility.

Evidence from real-world exposure

Epidemiological data supports these findings. Individuals exposed to TCE through work or hobbies show a significantly higher risk of developing Parkinson’s.

In one case study, people exposed to contaminated water had about a 70% higher risk. Another study found elevated rates of both Parkinson’s disease and certain cancers among office workers located near a contaminated site, highlighting that exposure is not limited to industrial settings.

Calls for stronger regulation and monitoring

Researchers are urging faster action to address what they describe as a serious public health threat. They recommend accelerating cleanup efforts in contaminated areas and improving monitoring of TCE in water, air and soil.

Measures such as vapor mitigation systems—similar to those used for radon—could help reduce indoor exposure.

Although a regulatory ban on TCE has been approved, its implementation has faced delays, and some uses are still permitted under extended timelines.

Scientists emphasize the need for further research to fully understand the chemical’s role in Parkinson’s disease and other illnesses, warning that millions of people may currently be exposed without their knowledge.