A man from Southern California was arrested on Monday for allegedly smuggling refrigerants into the United States from Mexico, with federal prosecutors stating that he is the first person to be charged with violating regulations aimed at reducing the use of greenhouse gases that contribute to climate change.

According to the indictment, Michael Hart of San Diego smuggled ozone-depleting chemicals across the border, hiding them under a tarp and tools in his vehicle. He then advertised them for sale on the internet, as per a statement from the U.S. Attorney’s Office.

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

This case represents the first prosecution in the United States involving 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.

U.S. Attorney Tara McGrath stated, “This is the first time the Department of Justice is prosecuting someone for illegally importing greenhouse gases, and it will not be the last. 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 and are used in various applications, including refrigeration, air conditioning, building insulation, fire extinguishing systems, and aerosols.

Hart has been ordered to return to court on March 25.