Two business owners in St. Petersburg, Florida, face felony charges after state wildlife officials say they scattered around 1,500 toxic mothballs on St. Pete Beach in April, allegedly to prevent imperiled black skimmer birds from nesting near their businesses. The men—Robert Czyszczon, owner of the Plaza Beach Hotel, and Christopher Monroe, owner and manager of Chris’ Beachside Bar—were arrested after a months-long investigation by the Florida Fish and Wildlife Conservation Commission (FWC).

Wildlife officials first responded to St. Pete Beach on April 20, after reports of more than 1,000 mothballs found behind the Plaza Beach Hotel. The next day, another 500 mothballs were discovered in the same spot. Volunteers from the Audubon Society and local advocacy groups assisted in removing the chemicals before the black skimmers arrived for nesting season.

Investigators said surveillance footage, cell phone data, and receipt records from a local Walmart linked Czyszczon and Monroe to the purchase and placement of the mothballs. Text messages between the men showed they were concerned about losing up to $50,000 in business if the birds nested behind the hotel, and they discussed ways to prevent the birds from returning.

Mothballs contain chemicals that are toxic to both humans and animals, and their use as a wildlife repellent is illegal in Florida. The FWC said that scattering the mothballs posed health risks not only to wildlife—including the state-protected black skimmer, which is threatened by habitat loss—but also to people and marine life, as mothballs can be blown into the water. Disrupting nesting habitat can have lasting negative effects on bird populations.

Both Czyszczon and Monroe were charged with felony commercial littering and a misdemeanor count of attempting to take a state-listed imperiled species by harassment. If convicted, each could face up to five years in prison, fines of up to $5,000, and up to five years of probation. FWC Major Evan Laskowski said, “The illegal use of chemicals that can harm wildlife has no place on Florida's beaches, especially in areas where threatened and endangered shorebirds depend on safe nesting habitat.”

Local environmental advocates called the incident an act of sabotage but noted that the black skimmer colony returned and successfully nested after the cleanup. Authorities have not yet said if others may face charges.