A popular fly bait is being misused to kill raccoons and other animals.

A popular fly bait is being misused to kill raccoons and other animals.

Tambako The Jaguar/Flickr/Creative Commons

Regulators move to limit wildlife deaths from misuse of deadly fly killer

This past May, a dog named Gunner wandered into his neighbor’s barn and lapped sweet blue liquid from two pie tins on the floor. Then he collapsed and started to convulse. When Gunner’s veterinarian heard the story, he immediately guessed what was in the tins, according to a case summary from the Office of Indiana State Chemist (OISC). It was a mixture of Coca Cola and methomyl, a chemical sold to attract and kill flies.

Gunner eventually recovered, but other animals have been less lucky. Over the past few decades, wildlife researchers and environmental regulators in the United States have become increasingly alarmed by the intentional misuse of methomyl to kill “nuisance” wildlife including skunks and raccoons. Sometimes, however, the victims include dogs, cats, and even bald eagles.

“It’s indiscriminate, intentional poisoning of wildlife,” says Brian Rowe, who recently retired as pesticide section manager at the Michigan Department of Agriculture & Rural Development in Lansing. “Some of them die with their face in the pan that they’re licking out of. I mean, it kills them that quick.”

In response, this week Michigan officials are considering new rules to limit the use of the pesticide. If the rules are approved, as expected, Michigan would join a growing number of states and the federal Environmental Protection Agency (EPA) in trying to prevent the misuse of methomyl, in part by restricting who can buy it and requiring new warning labels. But some observers fear the labels—which depict a raccoon in a red circle with a slash through it—might unintentionally make matters worse.

Methomyl, which first hit the market in 1966, has a broad range of uses, including killing pests in agriculture. Under federal and state law, only licensed applicators can purchase and use the most potent methomyl products. But fly baits, which contain relatively low concentrations of methomyl, are available to everyone. The baits— commonly sold under the trade names Golden Malrin, Lurectron Scatterbait, and Stimukil—are designed to be placed in fly-prone areas, such as livestock enclosures.

Consumers, however, soon figured out that the baits could be repurposed for what is often called “critter control” on internet message boards. The poison is especially popular among sweet corn growers who are having trouble with raccoons, Rowe says, although people have employed it in attempts to kill everything from rodents to wolves. Rowe has documented more than 50 examples of people swapping advice and poison recipes online, and as of January, instructions for how to kill raccoons with methomyl are still among the first results of a Google search for “Golden Malrin.”

Rowe first heard about misuse of fly bait in the 1990s, and he started raising the issue with state and federal regulators in 2006. At first, it was hard to get anyone to take it seriously, he says. People dismissed it as a local problem, even though more than half of states that responded to Rowe’s inquiries confirmed they had at least one incident on record.

Between 2010 and 2012, regulators in Michigan and Indiana decided to see how deep the problem went. Agents posed as customers in hardware and farm supply stores, asking how to get rid of skunks or raccoons. In about a quarter of cases, the salespeople recommended fly bait. One store even had a sign: “Golden Malrin®—Kills Groundhogs, Opossums and Raccoons—One cup fly bait and one can regular coke.”

“We didn’t think it was a problem in Indiana … and then finally when we started looking, we said holy smokes, it is a problem,” says Leo Reed, a certification and licensing manager at OISC in West Lafayette. “Our contention is that if methomyl [fly bait] is being sold in your state, it’s being misused in your state.”

Starting in 2010, the six states in EPA’s Region 5, a regulatory region that includes Indiana and Michigan, joined forces to call for change from EPA. Their proposed solution: Reclassify methomyl fly baits as “restricted use” products. This would get the poison out of the hands of the general public, limiting access to trained, licensed applicators and the people they supervise.

The fly bait companies opposed that solution, however, and instead reached a compromise with EPA in April 2015. By early 2017, the agreement calls for the companies to stop distributing methomyl fly baits to general retailers such as hardware stores, and to stop making small containers. Farm supply stores will still be able to sell larger 4.5- and 18-kilogram containers, which will come with new warning labels and explanatory pamphlets. The companies and EPA plan to monitor reports of misuse through 2020, and further restrict use to licensed applicators if incidents aren’t “significantly reduced.”

The maker of one of the products, Golden Malrin, says the arrangement makes sense. “[Golden Malrin] is an important tool in reducing fly populations which have the potential to spread disease to livestock and humans,” wrote Mark Newberg, a representative for Wellmark International in Schaumburg, Illinois, which produces Golden Malrin, in an email. “We did what was asked of us by the EPA to keep the product available as a fly insecticide.” 

Methomyl products will now carry this logo, meant to warn against using them to poison raccoons. But some observers worry it might carry the opposite message.

Methomyl products will now carry this logo, meant to warn against using them to poison raccoons. But some observers worry it might carry the opposite message.

Some observers, however, have questions about the new warning labels. The red raccoon symbol is meant to be eye-catching, and according to EPA it means “not for use on raccoons.” But in some people’s eyes, it looks more like it is advertising the chemical as a good way to get rid of raccoons.

“Isn’t that the best advertisement for misuse you can possibly have?” Indiana’s Reed says. When he described the symbol at a meeting of regulators last year, participants started laughing.

The image could be misinterpreted, says Andrea Rother, an environmental and occupational health specialist at the University of Cape Town in South Africa who studies how people interpret symbols on pesticide labels. Before adopting the raccoon symbol, she says, the companies or EPA should have tested it with consumers.

EPA officials say no such testing occurred, but are confident that people will read the new labels as intended. The agency notes that text below the symbol reads “it is illegal to use this product with the intention to kill raccoons, skunks, opossums, coyotes, wolves, dogs, cats, or any other non-target species.”

“We believe that these two warnings together will make it clear that these uses are not legal,” wrote an EPA spokesperson in an email.

Even if consumers do get the right message, they’re unlikely to change their behavior, Rother predicts. People who use fly bait to poison raccoons already know they aren’t following label directions. The most effective way to combat such deliberate misuse, she says, is to limit people’s access.

Some states are doing just that, going beyond EPA’s mitigation measures and instead making the products illegal for sale to the general public. Indiana reclassified methomyl fly baits as restricted use products in 2013. Michigan is following suit, with a hearing to finalize the restrictions scheduled for 19 February.

In the rest of the country, Rowe expects illegal poisonings to continue, at least while current EPA rules are in place. It will fall on researchers and regulators to document and report such incidents, he says, so that the companies and the EPA will have the data they need in 2020 to determine if the existing restrictions are working. 

Follow News from Science

Latest News

A 3D plot from a model of the Ebola risk faced at different West African regions over time.
Dancing sneakers on pavement