Farmworkers apply the fumigant 1,3-Dichloropropene to a field in Salinas, Calif.
Farmworkers apply the fumigant 1,3-Dichloropropene to a field in Salinas, California. Credit: Sam Hodgson for CIR

There was big news coming out of the California Department of Pesticide Regulation earlier this month: A cancer-causing pesticide called 1,3-Dichloropropene will face new regulations, a move that the department says illustrates a commitment to public health.

But it appears that Dow AgroSciences, which manufacturers 1,3-D, is getting what it has wanted for years.

The popular pesticide, which is pumped into the soil before crops such as strawberries and sweet potatoes are planted, is a gaseous chemical that can go airborne near farms, homes and schools.

Because of that, the state limits how much 1,3-D can be used in each community every year. This system is known as a “township cap.”

Under the new regulations, the state did away with a loophole that allowed growers to regularly go far above those limits. The decision became the focal point of a recent spate of news stories about how the state had cracked down on risky pesticide use.

That loophole was problematic because the department’s own scientists had strenuously objected to the system, which had been proposed by Dow. It put more than 1 million Californians at a higher risk for cancer than regulators thought was acceptable, as our previous reporting has shown.

But while it closed that loophole, the department simultaneously increased the baseline amount that can be used in each community a year by 50 percent – a move that Dow has been advocating for since 2008, department documents show.

For years, the department’s in-house scientists had rejected Dow’s idea to bump up the township cap because they were concerned it would increase cancer risk to unacceptable levels.

The Department of Pesticide Regulation says that its recent decision to increase the annual cap was independent of any Dow proposal, and the new limit is based on additional research on the chemical, plus data from air monitoring, pesticide use and weather patterns.

But one of the scientists who helped oversee the state’s risk assessment of 1,3-D says he’s not convinced.

“I was aware of proposals presented by Dow to increase the township caps while we were conducting the assessment,” said Joseph Frank, a senior toxicologist who retired in June 2012. “My staff and I rejected them as we felt we could not support them. At this time, I am still convinced that based on available data and appropriate modeling, ambient exposure to 1,3-D places residents and bystanders at considerable risk.”

Scientists with the state’s Office of Environmental Health Hazard Assessment also analyzed the new township cap and expressed concerns about them before they were finalized. The agency wrote that it “does not believe that the proposed cap can assure adequate health protection for all residents of a given township.”

Charlotte Fadipe, a spokeswoman for the Department of Pesticide Regulation, said that its scientists disagree.

Bernice Yeung can be reached at Follow her on Twitter: @bmyeung


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Bernice Yeung is a reporter for Reveal, covering race and gender. Her work examines issues related to violence against women, labor and employment, immigration, and environmental health. Yeung was part of the national Emmy-nominated Rape in the Fields reporting team, which investigated the sexual assault of immigrant farmworkers. The project won an Alfred I. duPont-Columbia University Award and a Robert F. Kennedy Journalism Award and was a finalist for the Goldsmith Prize for Investigative Reporting. Yeung also was the lead reporter for the national Emmy-nominated Rape on the Night Shift team, which examined sexual violence against female janitors. That work won an Investigative Reporters and Editors Award, the Society of Professional Journalists Sigma Delta Chi Award for investigative journalism, and the Third Coast/Richard H. Driehaus Foundation Competition. Those projects led to ​​her first book in 2018, “In a Day's Work: The Fight to End Sexual Violence Against America's Most Vulnerable Workers.”  

A former staff writer for SF Weekly and editor at California Lawyer magazine, Yeung has had her work appear in a variety of media outlets, including The New York Times, The Seattle Times, The Guardian and PBS FRONTLINE. She has a bachelor's degree in journalism from Northwestern University and a master's degree from Fordham University, where she studied sociology with a focus on crime and justice. She was a 2015-16 Knight-Wallace fellow at the University of Michigan, where she explored ways journalists can use social science survey methods in their reporting. Yeung is based in Reveal's Emeryville, California, office.