California is restricting the use of a certain type of rat poison that poses a threat to mountain lions and other wildlife under a bill signed into law Tuesday by Gov. Gavin Newsom.
The California Ecosystems Protection Act (AB 1788) prohibits the use of second-generation anticoagulant rodenticides until the state’s pesticide regulation chief can certify they’re being used in a manner that reduces the threat to wildlife.
There are exemptions in place for use in agriculture and locations where the poisons are deemed necessary for public health and safety.
Anticoagulant poisoning is one of the leading causes of death for pumas roaming the Santa Monica Mountains. Studies have shown the toxic compounds wind up poisoning a large range of animals, including bobcats, California condors, spotted owls and San Joaquin kit foxes.
Last month, biologists announced a young mountain lion and a bobcat they were tracking in the Santa Monica Mountains both died of rat poisoning.
The puma, P-76, was the third collared mountain lion to die of coagulopathy in the past two years, and the sixth overall in the study. Coagulopathy is rarely seen in bobcats, and officials called B-732’s death “an important finding.”
The bill’s author, Assemblymember Richard Bloom of Santa Monica, said he’s been fighting more than five years to get it passed.
“After many years of studying the impacts of these chemicals, we know that these poisons pose a serious threat to our wildlife,” he wrote in a tweet. “Today, I am grateful that hard pressed mountain lions and other animals will soon be a little safer.”
The measure was opposed by pest control companies, the California Chamber of Commerce and other business groups. In a letter sent to the state Senate this summer, the chamber said the products are “necessary to protect agricultural operations and ensure the public has access to safe food products.”
Second-generation anticoagulant rodenticides have a higher potency than other types of rat poison, and a single dose has a half-life of more than 100 days in a rat’s liver, according to the Center for Biological Diversity.
When larger species consume a poisoned rodent, the toxins are passed on.
Advocates say they cause wildlife to suffer a slow, agonizing death. And even when exposure doesn’t kill an animal, it can have other negative impacts on their health.
“Anticoagulants are wiping out the very wildlife that help control rodents naturally,” Lisa Owens Viani, director of Raptors Are The Solution, said in a statement. “There is a groundswell of support for this bill, which takes a giant step to reduce secondary poisoning.”
In recent studies, necropsies completed on 96% of mountain lions and 80% of raptors showed exposure to anticoagulant rodenticides, according to the governor’s office.
California banned consumer sales of the rodenticides’ active ingredients in 2014, but they’ve remained popular among certified pest control operators.
There are many alternatives to anticoagulant rodenticides. Those looking to learn about alternative rodent control methods can visit SafeRodentControl.org.