MADISON, Wis. – The Wisconsin Department of Justice (DOJ) joined a coalition in filing a petition challenging a U.S. Environmental Protection Agency (EPA) rule that would weaken regulations designed to phase down the use of hydrofluorocarbons (HFCs) in commercial equipment. HFCs are chemicals used for refrigeration and cooling that are up to 10,000 times more potent than the equivalent amount of carbon dioxide, and they are among the fastest growing source of greenhouse gas emissions both in the United States and around the world.

The rule would roll back some of the existing deadlines for industry to move from using HFCs as refrigerant gases to refrigerants with less greenhouse effect, known as Global Warming Potential (GWP). This undermines EPA’s current regulations under the American Innovation and Manufacturing Act of 2020 (AIM Act), which are designed to phase out HFCs by approximately 85% by 2036.

“This rule is consistent with the Trump administration’s clear pattern of taking action that harms the environment,” said AG Kaul. “This unwarranted rollback must be blocked.”

HFCs are widely used in commercial, residential, and mobile cooling systems, such as air conditioning and refrigeration. Once deemed a safer alternative for the environment relative to ozone-depleting substances (chlorofluorocarbons, or CFCs), which damage the earth’s ozone layer, HFCs were later discovered to pose a major threat to the climate. With greenhouse effects (or GWPs) hundreds to thousands of times higher than carbon dioxide over a hundred-year period, HFCs have been projected to contribute up to 0.5 degrees Celsius (about 0.9 degrees Fahrenheit) to global surface warming by 2100 if they are not controlled.

In December 2020, President Trump signed the bipartisan AIM Act into law. The AIM Act provides a framework through which the United States will phase down the production and consumption of HFCs by about 85% by 2036. That law limits production and imports of HFCs in the U.S. to declining amounts of historic baseline levels — 60 percent today, declining to 30 percent in 2029, and 15 percent in 2036.

The law requires EPA to help industry transition to a lower supply of these gases by setting limits for sectors with more readily available alternatives to protect costs and supply for those sectors that will take longer to transition. That’s what the prior Technology Transitions rule did: required specific sectors that use refrigerants to, when installing new equipment, install equipment that uses gases with lower GWP. For example, under the prior Technology Transitions rule, new remote condensing units — typically used to refrigerate food by retailers like supermarkets, bakeries, and conveniences stores —  were limited to using refrigerants with 150 to 300 GWP, depending on the system, starting January 1, 2026. With EPA’s rollback, new remote condensing units could use refrigerants with greater global warming potential (up to 1,400 GWP) until January 1, 2032.

Joining Wisconsin DOJ in filing the petition are the attorneys general of California, Colorado, Delaware, the District of Columbia, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nevada, New Jersey, New York, Oregon, Rhode Island, Vermont, and Washington, as well as the City of New York.