The Environmental Protection Agency (EPA) has determined that popular pesticides linked to declining bee populations also pose a threat to birds and, in some cases, small mammals and insects.

The EPA released preliminary scientific assessments of four chemicals from the neonicotinoid or “neonic” class of insecticides on Friday as part of an ongoing review that environmentalists and farmers are watching closely. Previous EPA assessments echoed research showing that neonics can harm the bees we rely on to pollinate crops when sprayed on cotton and certain fruits and vegetables.

“The EPA’s assessments confirm neonicotinoid pesticides are extremely harmful to birds and aquatic life at the very center of our ecosystems,” said Lori Ann Burd, director of the Center for Biological Diversity’s environmental health program, in a statement.

Environmentalists blame all four of the neonic pesticides under review at the EPA — clothianidin, thiamethoxam, dinotefuran and imidacloprid — for declining populations of honey bees, butterflies and other pollinators, including several endangered species. Of the four, imidacloprid is probably the most widely used and controversial.

In their most recent assessment, EPA scientists determined that imidacloprid poses an “acute risk” to birds when sprayed on crops. Birds, small mammals and insects could also be harmed if they eat crop seeds treated with the pesticide.

The findings echo a report published earlier this year that found imidacloprid and the controversial organophosphate pesticide chlorpyrifos can impair songbirds’ ability to find their way while migrating. Environmentalists are also concerned that the chemical may pose health risks to humans, including cancer and increased rates of autism in young children.

In 2016, the EPA also found that imidacloprid “potentially poses risk to [bee] hives when the pesticide comes in contact with certain crops that attract pollinators,” according to a preliminary assessment released at the time.