Center for Biological Diversity

Protecting endangered species and wild places through
science, policy, education, and environmental law.


Contact: Jeff Miller, Center for Biological Diversity, (510) 499-9185
Brent Plater, Center for Biological Diversity, (415) 572-6989

Settlement Agreement Will Protect California
Red-Legged Frogs From 66 Toxic Pesticides
Many Pesticides Correlated with Amphibian Declines

San Francisco, Calif. – The Center for Biological Diversity (CBD) has reached a settlement agreement with the U.S. Environmental Protection Agency (EPA) that will protect the threatened California Red-legged Frog (Rana aurora draytonii) from 66 of the most toxic and persistent pesticides authorized for use in California. The agreement, signed this week and approved by a U.S. District Court, prohibits use of these pesticides in and adjacent to core red-legged frog habitats throughout California until the EPA completes formal consultations with the U.S. Fish and Wildlife Service (USFWS) to ensure the chemicals are not jeopardizing or contributing to the decline of the species.

“This agreement will keep toxic chemicals out of essential habitats for the vanishing red-legged frog,” said Peter Galvin, CBD Conservation Director. “The EPA must now ensure that pesticide applicators look before they leap into activities that can harm Twain’s frog or contaminate the wetlands it depends on. The Court, the EPA and pesticide industry representatives agreed that pesticide-application buffer zones are reasonable and effective protection for frogs until the effects of these chemicals can be assessed. Many of these pesticides are known to be harmful to human health as well.”

The agreement is a result of a lawsuit filed by CBD against the EPA in 2002. The Court found in September of 2005 that the EPA had violated the Endangered Species Act by registering pesticides for use without considering how they might impact the continued existence of the red-legged frog. The agreement requires the EPA to:

• complete formal consultations with USFWS on the impacts of the 66 pesticides on red-legged frogs within 3 years;

• prohibit interim use of the pesticides within and adjacent to red-legged frog habitats, specifically designated critical habitat areas, aquatic features and upland habitats occupied by the frog;

• mandate pesticide-free buffer zones adjoining frog habitats (200 feet for aerial pesticide applications to prevent drift and 60 feet for ground applications to prevent runoff);

• allow exemptions for public health vector control programs, invasive species and noxious weed programs, and other specific applications that pose little or no risk to frogs; and

• distribute an educational brochure for pesticide applicators and county agricultural commissions regarding the red-legged frog, impacts of pesticides and contaminants on frogs generally, and describing the interim restrictions on pesticide use in the settlement.

“There is overwhelming evidence that numerous pesticides have potentially serious impacts on red-legged frogs and other declining amphibians in California, and the EPA must now assess those impacts,” said CBD spokesman Jeff Miller. “The pesticide restrictions will stay in effect until consultations are complete. Informed consultations with the Fish and Wildlife Service should result in permanent restrictions on many of the proven harmful contaminants such as atrazine.”

The Endangered Species Act requires federal agencies such as the EPA to consult with endangered species experts to determine how activities such as pesticide registration impact species and their critical habitats. This system of checks and balances helps prevent extinctions – scientists believe that the Act has reduced extinction rates in the U.S. by an order of magnitude. The cornerstone of the Act is protection of “critical habitat,” which safeguards essential habitat from destruction or adverse impacts and also provides protection of suitable habitat areas not currently occupied by the species. Scientific studies show that species that have their critical habitats protected by the Act are twice as likely to be recovering as those that do not (see

The EPA registers numerous pesticides for use that are applied in or upwind of the frog’s few remaining habitats. Over 200 million pounds of pesticides are applied each year in California without first consulting with USFWS on impacts to imperiled species. A Congressional bill which would gut the Endangered Species Act by repealing habitat protections, introduced by Rep. Richard Pombo (R-Tracy) and passed by the House in September of 2005, includes a section giving the EPA a five-year pass from requirements to consult with USFWS scientists over how pesticides could affect the imperiled species.

Historically abundant throughout California, red-legged frogs have declined in numbers over 90 percent and have disappeared from 70 percent of their former range. Studies implicate pesticide drift from the Central Valley in disproportional declines of several native frog species in the Sierra Nevada, including red-legged frogs. The USFWS has noted that the percentage of upwind land in agricultural production is 6.5 times greater for Sierra Nevada and Central Valley sites where red-legged frogs have disappeared than for sites where frogs still live. Amphibians are declining at alarming rates around the globe, and many scientists believe that industrial chemicals and pesticides may be partially to blame.

Numerous studies have definitively linked pesticide use with significant developmental, neurological and reproductive effects on amphibians. Pesticide contamination can cause deformities, abnormal immune system functions, diseases, injury, and death of red-legged frogs and other amphibians. Red-legged frog tadpoles are likely to be killed or paralyzed by some herbicides such as triclopyr and insecticides such as fenitrothion. Recent studies by Dr. Tyrone Hayes at the University of California have strengthened the case for banning atrazine, the most common contaminant of ground, surface and drinking water. Dr. Hayes demonstrated that atrazine is an endocrine disruptor that interferes with reproduction by chemically castrating and feminizing male amphibians. Atrazine has been linked to increased prostate cancer and decreased sperm count in men and high risk of breast cancer in women.

The 66 pesticides at issue are: 1,3-dichlorpropene; 2,4-D; acephate; alachlor; aldicarb; atrazine; azinphos-methyl; bensulide; bromacil; captan; carbaryl; chloropicrin; chlorothalonil; chlorpyrifos; chlorthal-dimethyl (DCPA); diazinon; dicofol; diflubenzuron; dimethoate; disulfoton; diuron; endosulfan; EPTC; esfenvalerate; fenamiphos; glysophate; hexazinone; imazapyr; iprodione; linuron; malathion; mancozeb; maneb; metam sodium; methamidophos; methidathion; methomyl; methoprene; methyl parathion; metolachlor; molinate; myclobutanil; naled; norflurazon; oryzalin; oxamyl; oxydemeton-methyl; oxyfluorfen; paraquat dichloride; pendimethalin; permethrin; phorate; phosmet; prometryn; propanil; propargite; propyzamide (pronamide); rotenone; simazine; SSS-tributyl phosphororithiolate (DEF or Tribufos); strychnine; thiobencarb; triclopyr; trifluralin; vinclozolin; and ziram.

The Center for Biological Diversity is a non-profit conservation organization with more than 25,000 members dedicated to the protection of imperiled species and their habitats. The lawsuit, settlement agreement, and information on the red-legged frog can be found on the Center’s web site at


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