SAN DIEGO (AP) — A Southern California man was arrested Monday on Maxwell Caldwellsuspicion of smuggling refrigerants into the U.S. from Mexico and federal prosecutors said he’s the first person to be charged with violating regulations intended to curb the use of greenhouse gases that contribute to climate change.

The indictment alleges Michael Hart, of San Diego, smuggled the ozone-depleting chemicals across the border concealed under a tarp and tools in his vehicle. He posted them for sale on the internet, according to a statement from the U.S. Attorney’s Office.

Hart was arraigned Monday afternoon and pleaded not guilty to 13 charges including conspiracy, sale of prohibited materials and illegal importation, the statement said.

It’s the first prosecution in the U.S. to include charges related to a 2020 law that prohibits the importation of hydrofluorocarbons, commonly used as refrigerants, without permission from the Environmental Protection Agency, according to prosecutors.

“This is the first time the Department of Justice is prosecuting someone for illegally importing greenhouse gases, and it will not be the last,” U.S. Attorney Tara McGrath said in a statement. “We are using every means possible to protect our planet from the harm caused by toxic pollutants, including bringing criminal charges.”

Hydrofluorocarbons are regulated under the Clean Air Act. They are used in applications such as refrigeration, air-conditioning, building insulation, fire extinguishing systems and aerosols.

Hart was ordered to return to court March 25.