Back to News Releases

New Rules Governing Use of Fumigant Pesticide 1,3-D

Contact: Charlotte Fadipe
916-445-3974 |
October 6, 2016 (16-8)

(SACRAMENTO) – Guided by a new scientific assessment of health risks, the California Department of Pesticide Regulation (DPR) today announced an update to the way the fumigant pesticide 1,3-Dichloropropene (1,3-D) is managed and used in California.

This pesticide, commonly known by the brand name Telone, is used to control insects, nematodes and other organisms in the soil that threaten a variety of crops including sweet potatoes, almonds, strawberries, grapes and carrots. It has been used in the United States since 1954 and in California since 1970, mostly in the San Joaquin Valley and Central Coast regions.

The new restrictions, which will take effect on January 1, 2017, include:

  • An annual limit of 136,000 pounds* within each six mile by six mile area known as a township. (Townships are used to track pesticide applications). Currently, township limits are between 90,250 and 180,500 pounds per year.
  • Discontinuing the current practice of carrying forward or "rolling over" unused allocations of 1,3-D from one year for use in future years
  • A ban on the use of this pesticide during December, when weather conditions tend to make air concentrations higher

"These changes reflect my commitment to a more effective approach to protecting the public from harm from pesticide use, particularly fumigants,"" said Brian Leahy Director of DPR. "The new method for limiting use guards against harm from the extended use of this fumigant, while retaining it as a tool to fight pests that could otherwise harm California agriculture."

1,3-D is a fumigant pesticide that is injected into the soil to sterilize it before the crop is planted. In 2007, the U.S. Environmental Protection Agency classified it as a likely carcinogen, and it is included on California's Proposition 65 list of chemical "known to the state to cause cancer."

California is the only state to limit how much of the pesticide can be used annually in any area. 1,3-D is also a restricted material, and as such can only be applied by trained, certified applicators under a permit from a County Agricultural Commissioner.

In the last decade, DPR's regulations allowed growers to use varying amounts of 1,3-D in a township annually. These limits ranged from 90,250 pounds to more than 180,500 pounds provided growers used less in other years. It also allowed unused allocations of the pesticide to be carried over into the following years. As a result of these flexible limits, some growers often used more than 136,000 pounds of this pesticide annually per township. That will no longer be allowed to continue.

The new annual limit of 1,3-D was developed after DPR completed a comprehensive scientific study of this chemical, PDF (3 mb), known as a risk assessment, and after reviewing air monitoring data.

"DPR is continuously revising and updating how pesticides are used in California," said Leahy. "While our studies continue to show that we have been protective of human health, I believe that overhauling the way we manage the pesticide, to be based upon a fixed annual amount, will be health protective and simpler to manage."

More background can be found on the 1,3-Dichloropropene Regulatory Documents and Activities page.

* All pounds of 1,3-D are adjusted using application factors that include fumigation method, month, and region


Find us on Facebook Follow us on Twitter Watch us on Youtube