A common and widely used chemical may be fueling the rise of the world’s fastest growing brain condition—Parkinson’s disease. For the past 100 years, trichloroethylene (TCE) has been used to decaffeinate coffee, degrease metal, and dry clean clothes. TCE causes cancer, is linked to miscarriages and congenital heart disease, and is associated with a 500% increased risk of Parkinson’s disease.
In a hypothesis paper in the Journal of Parkinson’s Disease, an international team of researchers—including University of Rochester Medical Center (URMC) neurologists Ray Dorsey, MD, Ruth Schneider, MD, and Karl Kieburtz, MD—postulated that TCE may be an invisible cause of Parkinson’s.
In the paper they detailed the widespread use of the chemical, the evidence linking the toxicant to Parkinson’s, and profile seven individuals, ranging from a former NBA basketball player to a Navy captain to a late U.S. Senator, who developed Parkinson’s disease either after likely working with the chemical or being exposed to it in the environment.
The connection between TCE and Parkinson’s was first hinted at in case studies more than 50 years ago. In the intervening years, research has shown that TCE readily enters the brain and body tissue and at high doses damages the energy-producing parts of cells known as mitochondria. Individuals who worked directly with TCE have an elevated risk of developing Parkinson’s. However, the authors warn that, “millions more encounter the chemical unknowingly through outdoor air, contaminated groundwater, and indoor air pollution.”
Beyond the risks to water, the volatile TCE can readily evaporate and enter people’s homes, schools, and work places, often undetected. Today, this vapor intrusion is likely exposing millions who live, learn, and work near former dry cleaning, military, and industrial sites to toxic indoor air.
The authors proscribed a series of actions to address the public health threat posed by TCE. They argued for more research to better understand how TCE contributes to Parkinson’s and other diseases. In addition, the authors called for finally ending the use of these chemicals in the U.S. PCE is still widely used today in dry cleaning and TCE in vapor degreasing. Two states, Minnesota and New York, have banned TCE, but the federal government has not, despite findings by the EPA as recently at 2022 that the chemicals pose “an unreasonable risk to human health.”