Cancer-Causing Chemical In California’s Tap Water


For decades, Shell and Dow hid a highly potent cancer-causing chemical — TCP — in two widely used pesticides, contaminating drinking water for millions of people in California and beyond, according to lawsuits detailed in a new report from EWG. The lawsuits were filed by Californian communities mostly located in the San Joaquin valley.  California produces two-thirds of America’s fruits and nuts, and a third of its vegetables resulting in widespread use of pesticides.

The chemical TCP is a cancer-causing byproduct present in these 2 pesticides which were widely used in the 1980s.  They have been discontinued or reformulated a long time ago but not before polluting the Californian groundwaters. According to documents unveiled in the lawsuits, Dow and Shell saved millions of dollars by not properly disposing of TCP.

TCP has been found to cause stomach, liver and other cancers in rats, and is classified by the National Toxicology Program as “reasonably anticipated” to cause cancer in people. The EPA says long-term TCP exposure is also linked to liver and kidney damage. Finally, TCP is in California’s official registry of chemicals known to cause cancer.

TCP in Groundwater
The chemical has been detected in 94 water systems providing water to 8 million of Californians. It was also detected outside California in 13 other states’ water supplies serving 4 million people. Currently, there is no federal standard for TCP.

Californian officials will meet next week to decide whether TCP in tap water should be regulated – 28 years after it was detected. California State Water Resources Control Board have proposed a legal limit of 5 parts per trillion, the lowest level current technology can reliably detect.

“This is an outrageous story of how Shell and Dow essentially got farmers who bought the pesticide to pay to help them get rid of a hazardous waste,” said Bill Walker, EWG’s managing editor and co-author of the report. “How many other hidden examples are there of chemical companies endangering communities through toxic deception?”

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