A new UCLA Health study shows that long-term exposure to the pesticide chlorpyrifos dramatically increases the risk of Parkinson's disease. People living in areas with permanent exposure are more than 2.5 times more likely to develop this disorder. Laboratory experiments on animals confirmed these findings. Animals exposed to the chemicals showed movement problems. In addition, they lost dopamine-producing neurons. They also showed an accumulation of a toxic protein similar to that seen in Parkinson's patients.