The California Department of Pesticide Regulation recently released new regulations limiting the use of second-generation anticoagulant rodenticides. The new regulations will limit the use of these long-lasting poisons to licensed pest control companies for use within 50 feet of a structure, with limited exceptions. They will not be sold in retail outlets for home use.  First generation rodenticides will still be available to non-licensed consumers since they are considered less likely to cause secondary poisoning of non-target species.

Public comments on the new regulations will be accepted until Tuesday, September 3.


These anticoagulants - brodifacoum, bromadiolone, difenacoum and difethialone - are blood-thinners that not only are fatal to targeted animals, they can severely harm or kill non-target wildlife and pets that prey on target species.  The toxins persist in animals for months, causing internal bleeding and oftentimes leading to a slow, painful death.


The new regulations were developed in response to research documenting the poisonings and deaths of at least 25 wildlife species in California, including raptors and mammals. Earlier this year, the Center for Biological Diversity took legal action calling for the state to protect wildlife from these powerful and insidious poisons.


Of particular concern are impacts to threatened and endangered species such as the Pacific fisher, Northern spotted owl, and San Joaquin kit fox. Other impacted species include eagles, owls, hawks, bobcat, marten, and mountain lion. These potent rodenticides can also harm or kill household pets that eat poisoned rodents.


Researchers at the University of California found second-generation anticoagulants in 70 percent of mammals and 68 percent of the birds they examined. Secondary poisoning of predators that eat poisoned rodents has been documented throughout the state in a variety of animals in urban, rural, and wilderness settings.


Research in remote areas of Northern California revealed high levels of anticoagulants in 75% of Pacific fishers, an endangered forest predator in the weasel family. In such remote settings, the use of these poisons is thought to be associated with large “trespass” marijuana-growing operations on public lands.


Since 1999 the California Department of Fish & Wildlife has continually recommended that the state ban second-generation rodenticides from retail sales and limit their use to licensed pesticide applicators. In 2008, the U.S. EPA banned retail sales of these rodenticides, but the restriction was reversed after pesticide manufacturers sued to government.  


Safe and effective alternatives to address rodents in homes and rural areas include rodent-proofing by sealing cracks and crevices, eliminating food sources and shelter such as wood piles, providing owl boxes to encourage natural predation, and use of rodent traps.


Tell the Department of Pesticide Regulation that it’s time to finally protect wildlife, particularly threatened and endangered species, from second-generation anticoagulants. Threats to the recovery of imperiled species like the Pacific fisher and Northern spotted owl were not adequately assessed when these poisons were registered for retail sales. Restricting the use of these potent poisons to only licensed applicators will significantly reduce unintended exposures to non-target wildlife and pets.


Currently, approximately 40% of these powerful poisons are used by licensed pesticide applicators, so banning retail sales won't entirely solve the problem, but it is a critical step in the right direction.


Submit comments on DPR Regulation No. 13-002, “Designating Brodifacoum, Bromadiolone, Difenacoum, and Difethialone as Restricted Materials (Second Generation Anticoagulant Rodenticide Products)” by 5pm on Tuesday, September 3.


by e-mail: Linda Irokawa-Otani This email address is being protected from spambots. You need JavaScript enabled to view it.

by U.S. mail:

Linda Irokawa-Otani, Regulations Coordinator

Department of Pesticide Regulation

1001 I Street, P.O. Box 4015

Sacramento, California 95812-4015