Scientists have cautioned against the use of a common dry-cleaning agent, which they believe might be causing Parkinson’s.

In a study, published Tuesday in the Journal of Parkinson’s Disease, scientists have collected evidence to date, augmenting their hypothesis.

The chemical in question is called trichloroethylene, or TCE. It is a colorless organic solvent that has been used in various industries for over a century. Mostly used as a degreasing agent in commercial or manufacturing facilities, it’s present in common household cleaning products, refrigerants, and dry-cleaning, as per Gizmodo. Naturally, people employed in these industries are at risk for exposure to TCE. Additionally, people in surrounding communities are also at risk since the chemical can contaminate soil and groundwater.

Now, some states in the U.S. have banned its use, but TCE remains widely present across the country.

New York and Minnesota recently banned TCE from most industrial uses. Moreover, the Environmental Protection Agency, this January, determined that TCE “presents an unreasonable risk of injury to human health” in its current usage.

High exposure to TCE is said to irritate the lungs and skin, and also cause light-headedness and headaches. Considered a carcinogen, its prolonged exposure is known to increase the risk of kidney cancer and maybe even other forms of cancer.

Some scientists have been trying to highlight the dangers of TCE for more than a decade.

Parkinson’s is a neurodegenerative disorder that hinders people’s movement and often causes dementia. According to the Parkinson’s Foundation, around 90,000 people in the U.S. are diagnosed with the condition every year, and a million Americans are believed to be afflicted by it.

“Millions of Americans have worked with TCE, and tens of millions have been (often unknowingly) exposed to the chemical through the water they drink and the indoor air they breathe,” author Ray Dorsey, a neurologist at the University of Rochester Medical Center, New York, told the outlet. “TCE is known to cause cancer and may be fueling the rise of the world’s fastest-growing brain disease.”

In the study, seven patients were identified whose Parkinson’s might be due to TCE. The list included former NBA player Brian Grant, diagnosed with Parkinson’s at the age of 36, and late U.S. Senator Johnny Isakson, who died in 2021.

These patients had a known history of living or working near sites where exposure to TCE was probably high, for instance, the military base Camp Lejeune.

Here, TCE and other chemicals contaminated the drinking water at the military base from the 1950s to 1980s, which most likely added cases of cancer and other illnesses, according to the Agency for Toxic Substances and Disease Registry, part of the Centers for Disease Control and Prevention.

However, more research is needed to be done to know whether and how TCE (as well as perchloroethylene, or PCE) could be causing Parkinson’s, the research team said.