A United States appeals court ruled on Thursday that federal regulators erred in allowing an insecticide developed by Dow AgroSciences onto the market, canceling its approval and giving environmentalists a major victory.
The ruling by the United States Court of Appeals for the Ninth Circuit, in San Francisco, is significant for commercial beekeepers and others who say a decline in bee colonies needed to pollinate key food crops is tied to the widespread use of a class of insecticides known as neonicotinoids.
The lawsuit was filed in 2013 against the Environmental Protection Agencyby a number of organizations representing the honey and beekeeping industries. The groups specifically challenged the E.P.A. approval of insecticides containing sulfoxaflor, saying studies have shown they are highly toxic to honeybees. Sulfoxaflor is a neonicotinoid subclass, according to the ruling.
“It’s a complete victory for the beekeepers we represent,” said Greg Loarie, a lawyer for the American Honey Producers Association, the American Beekeeping Federation and other plaintiffs in the case. “The E.P.A. has not been very vigilant.”
Dow said in a statement that it “respectfully disagrees” with the ruling and will “work with E.P.A. to implement the order and to promptly complete additional regulatory work to support the registration of the products.” The agency said it was reviewing the decision and would have no further comment.
Honeybees pollinate plants that produce roughly a quarter of the food consumed by Americans. The demise of the bees has become a hotly debated topic between agrochemical companies, which say the insecticides they sell are not to blame, and those who say research shows a direct connection between neonicotinoids and large bee die-offs.
The White House has formed a task force to study the issue, and the E.P.A. has said it is trying to address concerns.
In its ruling, the court found that the E.P.A. relied on “flawed and limited data” to approve the unconditional registration of sulfoxaflor, and that approval was not supported by “substantial evidence.”
In vacating the agency’s approval, the court said that “given the precariousness of bee populations, leaving the E.P.A.’s registration of sulfoxaflor in place risks more potential environmental harm than vacating it.”
The E.P.A. must obtain further data on the effects of sulfoxaflor on bees before it grants approval, the court said.
The Agriculture Department said this year that losses of managed honeybee colonies hit 42.1 percent from April 2014 through April 2015, up from 34.2 percent for 2013-14 and the second-highest annual loss to date.
Agrochemical companies that sell neonicotinoid products say mite infestations and other factors are the cause of the bees’ demise.