Most cases of Parkinson’s disease are considered idiopathic, i.e. they lack a clear cause. Yet researchers increasingly believe that one factor is environmental exposure to trichloroethylene (TCE).

It's a chemical compound used in industrial degreasing, dry-cleaning and household products such as some shoe polishes and carpet cleaners.

The clearest evidence around the risk of TCE is around workers who are exposed to the chemical in the work-place.

1. A 2008 peer-reviewed study in the Annals o...