California’s New Pesticide Rule Backfires: More 1, 3-D Used Even After Safety Limits

California officials claimed that a January 2024 rule would lower cancer risk from the chemical 1,3‑dichloropropane (1,3‑D) by cutting the amount that reaches the air.
Instead, data show growers applied a million more pounds last year than before the rule or in 2024. Kern and San Joaquin counties saw the biggest jumps, mainly on almond and grape farms.

What the Rule Entailed

• Setback distances were increased.
• Deeper soil injections required in moist ground.
• Tarps added to reduce fumes.

DPR officials argue that these steps let farmers keep using 1,3‑D at similar levels while cutting emissions.

The Reality on the Ground

• An air monitor in Delhi, California, recorded a 30 % rise in average airborne 1,3‑D during early 2025 compared with the same period in 2024.
• Farmworker groups point out that 1,3‑D is a known carcinogen and can cause acute symptoms such as breathing trouble, chest pain, eye irritation, and dizziness.
• A Chinese greenhouse worker died in 2023 after inhaling the fumigant.
• Forty countries have banned it, but California still permits its use.

Looking Ahead

DPR’s plan to speed up sustainable pest management lists no priority chemicals, leaving farmers without clear guidance.
The rising use of 1,3‑D after the rule’s implementation suggests that the intended safety gains have not materialized.