Popular dry-cleaning chemical puts millions at risk of Parkinson’s

Trichloroethylene (TCE) is a popular industrial chemical that is widely used as a solvent for dry cleaning, removing paints, cleaning machines, and equipment. A team of international researchers wants the U.S. government to put a ban on TCE because it causes Parkinson's disease.

In their recently published hypothesis, the researchers argue that people who've been exposed to TCE-contaminated water or air have a 500 percent increased risk of developing Parkinson's disease. Their findings are based on case studies of seven patients who are suffering from Parkinson's disease, possibly due to some form of TCE exposure.

Linking TCE and Parkinson's disease

The study authors suggest that they are not the only ones who have highlighted the association between TCE and Parkinson's. More than five decades ago, a group of researchers conducted TCE tests on mouse models, which revealed that a high dose of TCE damages mitochondria inside the body and brain cells.  

The past study also noted that TCE brings a sharp decline in dopamine levels which is also a symptom of Parkinson's. The authors of the current study reveal how many people in the U.S., including military personnel, have been exposed to TCE and what it did to their health. 

For instance, the researchers shed light on the life of former NBA player Brian Grant who spent his childhood at the U.S. Marine Corps base Camp Lejeune in North Carolina. He lived there with his father, who was serving as a Marine at that time. According to the researchers, this camp is one of the sites that have high TCE contamination.

"TCE is found in numerous military bases, including Camp Lejeune in North Carolina. From the 1950s to the 1980s, a million Marines, their families, and civilians that worked or resided at the base were exposed to drinking water levels of TCE and perchloroethylene (PCE), a close chemical cousin, that was up to 280 times above what is considered safe levels," the study authors note in the press release.

In 2006, Grant was diagnosed with Parkinson's disease. Former U.S. politician Johny Isakson who at a young age served at Georgia Air National Guard was also diagnosed with Parkinson's in 2015. The researchers assume that Isakson may have been exposed to high levels of TCE during the degreasing of airplanes.

They point out that even today, TCE and PCE are heavenly used for degreasing machines and dry cleaning cloths. The chemical pollutes water and soil and even evaporates and mixes into the air we breathe.

Therefore, it is highly likely that millions of people encounter this chemical on a daily basis —- "unknowingly through outdoor air, contaminated groundwater, and indoor air pollution." 

Time to say goodbye to TCE

The study usage of TCE reached its peak in 1970 because by then, it had emerged as an almost essential chemical for producing various medical, household, and military applications. There were two pounds of TCE available in the market for every U.S. citizen in the 70s. 

Interestingly, the U.S. Environmental Protection Agency also declared TCE as "an unreasonable risk to human health" in 2022. The authors suggest that considering the risk TCE poses, it is important we limit its concentration at sites where the environment is now heavily contaminated with this chemical. 

Groundwater, soil, and air at such places as well as near dry cleaning and metal degreasing facilities, should be regularly monitored to ensure the safety of people living nearby. Whereas Minnesota and New York have already put a ban on TCE, the authors suggest that the federal government should also do the same for the entire country. 

They believe TCE might also be linked with diseases other than Parkinson's (like cancer); however, to confirm their findings and these assumptions, further research is required. 

The hypothesis study is published in the Journal of Parkinson's Disease.