California Pesticide Regulators Say New Rules Protect Communities as Applications of a Dangerous Fumigant Rise
Key takeaways
- For decades, they knew that 1,3-dichloropropane, or 1,3-D, causes tumors in multiple organs in laboratory animals, which led the state to flag it as a carcinogen in 1989.
- But now, a year after regulators implemented a rule they said would reduce cancer risk by decreasing the amount of 1,3-D in the air, applications of the highly volatile compound have spiked, state records show.
- Growers applied a million more pounds of 1,3-D last year than they did in either 2023, before regulators enacted the “residential bystander” rule, or in 2024, after they implemented it.
Why this matters: environmental and climate reporting with long-term consequences.
June 4, 2026 Share This Article Republish. A tractor berms soil for almond trees on a farm near Lodi, Calif., on Oct. 13, 2025. Credit: Patrick T. Fallon/AFP via Getty Images Related Iowa’s Cancer Crisis Linked to Pesticides, PFAS, Fertilizer and Radon, Report Says Virginia House Delays Action on Bill Banning Paraquat California Sanctions Stark Disparities in Pesticide Exposure During Pregnancy Share This Article Republish Most Popular An Iowa Town Spent $800,000 on a New Well. It Pumps Undrinkable Water. Colorado River Faces ‘Devastating Consequences’ If Another Dry Winter Lands, Experts Warn EPA Rollbacks Could Raise AC, Refrigeration Costs Despite Promise of Lower Prices California regulators passed a rule in January 2024 that they said would protect communities from one of the state’s most popular, and dangerous, pesticides.
For decades, they knew that 1,3-dichloropropane, or 1,3-D, causes tumors in multiple organs in laboratory animals, which led the state to flag it as a carcinogen in 1989. Yet regulators allowed growers to fumigate fields with large volumes of 1,3-D to kill anything living in the soil before planting strawberries, almonds, grapes and other billion-dollar crops.
But now, a year after regulators implemented a rule they said would reduce cancer risk by decreasing the amount of 1,3-D in the air, applications of the highly volatile compound have spiked, state records show.