Seeds coated with insecticides should not be exempt from federal pesticide requirements, according to a lawsuit that seeks to end the “regulatory loophole.”

Food safety and environmental advocates claim the U.S. Environmental Protection Agency has overstepped its authority by treating neonicotinoid-coated seeds similarly to pesticide-infused paints and wood products, ignoring the broader impacts to bees, butterflies, birds and other wildlife.

“Neonicotinoids and other systemic pesticides absorb into the plant’s circulatory system as the plant grows,” according to the lawsuit. “Importantly, these systemic pesticides are predominately intended to have an external pesticidal effect on pests and predators of the growing plant.”

Under federal law, the EPA must register pesticides to ensure they meet environmental and safety standards, but the agency has an exception for certain products treated with these chemicals.

While the chemical is still regulated by EPA, the infused product isn’t subject to pesticide regulations under this “treated article exception.”

A federal complaint filed by the Center for Food Safety and Pesticide Action Network North America nonprofits claims the EPA has gone too far by including coated seeds in this exemption, since the pesticides have far-reaching effects beyond the seeds themselves.

“The growing plant from a coated seed is many thousands of times larger than the seed, and attractive to vastly different non-target wildlife, such as pollinators that are crucial to our food system,” the complaint said.

A coalition of beekeepers, farmers and environmental advocates previously petitioned the EPA to bring coated seeds under the registration and labeling requirements of the Federal Insecticide, Fungicide and Rodenticide Act, or FIFRA.

The recent complaint asks a federal court in California to eliminate the EPA’s exemption for coated seeds and to declare the petition’s denial last year violated pesticide and administrative laws.

The EPA isn’t commenting on the lawsuit, but in its denial, the agency said the exemption hasn’t caused it to ignore or overlook adverse effects from coated seeds.

Seed treatments are considered among other “exposure scenarios” in the EPA’s risk analysis of the neonicotinoid pesticides themselves, according to the agency.

“In addition to the thorough assessment, the agency believes that the seed treatments provide benefits including reducing the use of other pesticides that may have more harmful effects, preserving crop quality, and preventing pest damage,” according to EPA.

Coatings qualify for the exemption because they contain chemicals registered to “protect the seed and what the seed becomes,” and the seed must be used according to label instructions, the EPA said.

Without the exemption, different seed varieties and coating combinations may need to be individually registered under FIFRA, according to the agency. As a result, farmers would face greater costs and reduced flexibility.

The lawsuit alleges that instructions on seed bags are insufficient to protect pollinators because they’re not officially “pesticide labels” that are enforceable under FIFRA, limiting “how regulators investigate and respond to incidents like bee kills.”

The plaintiffs want the federal court to rule the exemption was unlawfully applied to seed coatings, but such a ruling wouldn’t necessarily stop such treatments, said Kristina Sinclair, attorney with the Center for Food Safety.

“After that, EPA will have to decide what to do. But that will be a separate proceeding from this case,” she said. “This case does not govern what EPA decides to do after it.”

CropLife America, an organization representing pesticide manufacturers, continues to believe the EPA made the right decision by refusing to end the exemption last year, according to Chris Novak, its president and CEO.

Bee colony numbers have risen over the past four decades as farmers increased their use of seed treatment technology, which is “thoroughly regulated and allows a targeted approach to pest control using decreased amounts of pesticides,” he said.