Chlorpyrifos Makes California List Of Most Dangerous Chemicals

The pesticide chlorpyrifos has been at the center of a lot of debate in recent years. Some environmentalists argue it’s so dangerous, it shouldn’t be used at all. But regulators wanted to gather more evidence before taking action.

This week, the California Office of Environmental Health Hazard Assessment moved to add chlorpyrifos to its Prop 65 list of substances known to cause cancer, birth defects and reproductive harm. The chemical has been banned from indoor use since 2001.

Allan Hirsch, chief deputy director of the office, said lots of new findings about the chemical’s impact on fetal brain development contributed to the decision.

“The panel was able to look at those, and look at the older studies, and they felt that all of the information from these studies taken together clearly showed that exposure to chlorpyrifos can harm the development of a child”

There are more than 900 other chemicals on the Prop65 list, including lead, solvents and food dyes. All Prop 65 chemicals are subject to strict labeling requirements.

California is widely viewed as having the most rigorous consumer protections against chlorpyrifos and other chemicals, though other states do have notification requirements for chemicals in children's products.

Many groups have pushed to get chlorpyrifos off the market entirely. The Obama administration proposed an all-out ban in 2015. President Donald Trump's appointed Environmental Protection Agency administrator Scott Pruitt ruled in spring 2017 that he would not ban the chemical.  

The California-based Pesticide Action Network wrote in a statement that the state's Prop 65 designation strengthens the case for a wider chlorpyrifos ban. 

“The Prop 65 listing affirms what scientists, doctors and communities have been saying for years – children’s developing brains are incredibly vulnerable to low amounts of the chemical during critical windows of development," said Emily Marquez, staff scientist with the organization. "State regulators should follow today’s decision by finally taking this chemical off the market.”

Products containing chlorpyrifos will have to be appropriately labeled by late 2018.