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New research suggests a chemical commonly used in dry-cleaning, degreasing, and even the decaffeination of coffee may be responsible for the steep increase in Parkinson’s disease cases. Hispanolistic/Getty Images
  • Scientists have proposed that the chemical trichloroethylene (TCE) may be linked to Parkinson’s disease.
  • TCE has been commonly used in dry cleaning, degreasing, and even the decaffeination of coffee.
  • New research suggests the chemical’s ability to enter the brain and damage cell mitochondria may be the cause.
  • Given the ubiquity of the chemical in the environment, the authors say its impact may be “enormous.”
  • Proposed solutions include banning TCE and protecting people from further exposure.

According to an international team of scientists, trichloroethylene (TCE) — a chemical that has commonly been used over the last century in applications as diverse as dry cleaning, metal degreasing, and the decaffeination of coffee — may be behind the steep rise in Parkinson’s disease cases.

The Parkinson’s Foundation explains that Parkinson’s disease is a neurodegenerative disorder affecting a part of the brain called the substania nigra, which contains cells that produce the neurotransmitter dopamine.

People with Parkinson’s experience symptoms such as tremors, slowness of movement, limb stiffness, and balance problems.

Prominent public figures who have the disease include Michael J. Fox and Muhammad Ali.

TCE contamination is present in up to a third of groundwater in the U.S., according to the authors. Additionally, there are 15 Superfund sites in Silicon Valley containing the chemical and it is present at the Marine Corps base Camp Lejeune.

The paper, which was published in the Journal of Parkinson’s Disease, outlines a hypothesis linking the common usage of TCE with Parkinson’s disease, speculating that it could be an “invisible” cause of the disease.

Commenting on the paper, Parkinson’s Foundation Chief Scientific Officer Dr. James Beck said, “We have known for some time the link between TCE exposure and Parkinson’s disease. I think this viewpoint article nicely summarizes the concerns around TCE exposure.”

In the paper, the researchers discuss the common usage of TCE as well as the evidence linking it with Parkinson’s disease.

The authors explain in the paper that TCE is lipophilic, meaning that it tends to dissolve in fatty tissues. Because of this, it is able to easily move into the brain and other body tissues and wreak havoc on cell mitochondrial function. Dopamine-producing cells are particularly sensitive to this type of toxin, which could explain why TCE exposure can lead to Parkinson’s disease.

They also profile seven people, including the late Senator Johnny Isakson.

Isakson used TCE during his military career to degrease airplanes and later developed Parkinson’s as well as renal cell carcinoma, a type of cancer linked to TCE exposure.

Dr. Ray Dorsey, co-author of the paper, said the issue first came to his attention when his colleague, co-author Dr. Caroline Tanner, told him about the exposures at Camp Lejeune.

The threat of TCE to public health is “enormous,” he said. “At one point, 10 million Americans (printers, embalmers, mechanics, dry cleaners, chip manufacturers, engineers, painters, metal workers, pilots and more) worked with it. Millions more have been exposed to it in the environment.”

Dorsey noted that a million Marines, their families, and civilians were exposed to the chemical at Camp Lejeune alone.

“Likely millions of us are living, working, or studying on top of TCE-contaminated groundwater (e.g., from Long Island to Newport Beach) from which TCE can evaporate and enter our homes, workplaces, and schools,” said Dorsey.

Dorsey said a few things need to be done to deal with the problem of TCE contamination.

First, it and another industrial solvent, tetrachloroethylene (PCE), need to be banned.

Second, those who are at risk of exposure need to be notified and protected with home remediation systems similar to what have used for radon.

Finally, more research is needed to explore the association between TCE and Parkinson’s disease, he said.

The U.S. Centers for Disease Control and Prevention explains that people can be exposed to TCE through contaminated air, water, food, or soil or through direct skin contact.

With a third of all groundwater possibly being contaminated, you are most likely to receive exposure by drinking contaminated water, but you can also be exposed to it through the air as it’s released from contaminated water.

Another important way that you can come into contact with TCE is if you work in an industry where the chemical is produced or used, such as the degreasing industry. It can enter the body either through breathing the fumes or through direct skin contact.

Contaminated soil, such as at landfills, is also a significant way that you can be exposed.

Additionally, if you eat foods that are contaminated or come in into contact with consumer products containing TCE it can enter your body.

The CDC notes that TCE is widely used as a solvent, including in adhesives, lubricants, paints, varnishes, paint strippers, pesticides, and cold metal cleaners.

These products should have information on their labels detailing how to minimize exposure.

Additionally, in the workplace, the Occupational Safety and Health Administration (OSHA) requires that your employer provide you with a material safety data sheet (MSDS) explaining risks and safe handling procedures for any chemicals that you are working with.

The Agency for Toxic Substances and Disease Register (ATSDR) explains that if you’ve recently been exposed to TCE, a medical professional can test for its presence in your blood, breath, or urine.

Tests can also be done to detect its presence in the air where you have been.

However, once you’ve been exposed, there is no treatment that can be done to remove it from your body. It will either leave via your breath or be excreted into your urine by your kidneys.

They advise staying away from any known areas of contamination, such as contaminated water, soil, or air.

Additionally, you should follow any safety recommendations on products containing TCE and always use them in well-ventilated areas with proper personal protective equipment like chemical-protective gloves, safety goggles, and respirators.

In the short term, high TCE exposure can cause irritation, unconsciousness, or even death.

It is important to seek prompt medical attention if you have had a large exposure to the chemical.

If conditions are safe to do so, the person should also be moved to fresh air and contaminated clothing removed. Flush the skin and eyes with water if they have been exposed.

In the long term, TCE exposure has been linked to kidney cancer as well as Parkinson’s disease. ATSDR suggests that the best protective measure you can take is to prevent being exposed to it in the first place.