In a rare show of defiance of the Trump administration, key Senate Republicans joined Democrats on Thursday in agreeing to phase out chemicals widely used in air conditioners and refrigeration that are warming the planet.

Despite the Trump administration’s refusal to join a global agreement to reduce hydrofluorocarbons, which are among the world’s most potent drivers of climate change, a push by U.S. firms and environmentalists appears to have swayed lawmakers.

“This agreement protects both American consumers and American businesses,” said Sen. John Barrasso (R-Wyo.), who chairs the Environment and Public Works Committee. “We can have clean air without damaging our economy."

The proposed phase-down will be offered as an amendment to a bipartisan energy bill, though it is unclear whether it will clear both chambers and be signed into law by President Trump before Congress adjourns in January.

An unusual coalition of business and environmental groups — including the National Association of Manufacturers, the U.S. Chamber of Commerce, FreedomWorks and the Natural Resources Defense Council — have been pushing Trump administration officials for months to support the Kigali Amendment, a 2016 agreement by nearly 200 countries to slash the use of a group of organic compounds that deplete the ozone layer and drive global warming. Some conservative organizations, including the Heritage Foundation and the Competitive Enterprise Institute, have sought to block Senate approval of the treaty.

The proposed legislation would closely mirror the requirements of the Kigali Amendment. A spokesman for the White House declined to comment.

Hydrofluorocarbons, also known at HFCs, are used in nearly every American household to cool everything from refrigerators to cars. They were widely introduced three decades ago as a substitute for chlorofluorocarbons, a different set of chemicals that were depleting Earth’s ozone layer. While that helped repair the ozone layer, scientists have identified HFCs as a significant driver of climate change — thousands of times more potent than carbon dioxide. Cutting these emissions, one of the fastest-growing greenhouse gases in the United States, could avert a 0.5-degree Celsius (0.9-degree Fahrenheit) global temperature rise by the end of the century.

Barrasso joined Thursday with Sens. Thomas R. Carper (D-Del.) and John Neely Kennedy (R-La.) in proposing to phase out the production and importation of HFCs by 85 percent over the next 15 years. That would put the United States on a path to meet the targets outlined under the Kigali Amendment, which modifies the 1987 Montreal Protocol, an international treaty to preserve the ozone layer.

The Senate proposal excludes six specific uses of HFCs, including fire suppression on aircraft, bear repellent used by hikers and inhalers required by people with asthma, and it preempts states from regulating HFCs used for those products for five years. Some states have been regulating the chemicals in the absence of federal action. Barrasso obtained language that would prevent the timelines for phaseout from becoming more stringent.

“This amendment would spur billions of dollars of economic growth in domestic manufacturing and create tens of thousands of new jobs, all while helping our planet avoid half a degree Celsius in global warming,” Carper said in a statement. “At a time when we could all use some good news, this is great news for our economy and our planet. Let’s get it done.”

U.S. corporations, including Honeywell and Chemours, want to the country to phase out the use of HFCs because they manufacture less-harmful alternative coolants and see market opportunities in the United States and abroad. Honeywell, based in Morris Plains, N.J., started researching HFC alternatives 20 years ago and is producing them in its Baton Rouge plants and in partnership with companies overseas. Chemours has been making a new coolant for auto air conditioners in its Corpus Christi, Tex., plant for more than a year.

The Air-Conditioning, Heating, and Refrigeration Institute said its members have invested several billion dollars in development and that approval of the bill would lead to the creation of 33,000 new jobs, increase U.S. manufacturing output by $12.5 billion, improve the balance of trade and boost exports by 25 percent.

Environmental advocates, meanwhile, celebrated the possibility of retiring a class of chemicals that is contributing to the climate crisis.

David Doniger, senior strategic director of the Natural Resources Defense Council’s climate and clean energy program, called the proposal “a major breakthrough.”

“It sends a strong signal that these climate-damaging chemicals are on their way out, and safer alternatives are on the way in,” Doniger said in a phone interview.

Durwood Zaelke, president of the Institute for Governance and Sustainable Development, called the bipartisan deal “remarkable.”

The Trump administration has never submitted the Kigali Amendment for a Senate vote, though 17 Republican senators have asked it to do so.

Some manufacturers remain concerned that by passing a domestic bill to slash these chemicals, it will make it harder to muster support for Senate approval of the international treaty in the next Congress. If the United States does not ratify the treaty, American companies may encounter obstacles selling their products overseas, they say.

Zaelke said that while that remains a risk, he noted that companies will still have a strong incentive to press for ratification. “The industry will say, ‘We still need it,’” he said. “They need it for their export market. They will press this.”

Democratic presidential candidate Joe Biden has said he would press for ratification of the treaty.

Meanwhile, some conservative think tanks have opposed a reduction in HFCs, suggesting that alternative coolants will increase prices of consumer goods. In a statement to the Senate Environment and Public Works Committee this year, Heritage Foundation deputy director Nick Loris said that “the reality is that the cost of the phase out would likely come at significant cost to American families and businesses. New air conditioning units for homeowners as well as car owners will be significantly more expensive.”

Loris said “regulations are not jobs creators. Forcing a new refrigerant on consumers means businesses will have to comply with the new regulation.”

As the planet warms, the demand for air conditioning is growing globally, and countries such as India and China have adopted plans to increase energy efficiency and use less harmful refrigerants. China, the world’s largest producer of HFCs, is in the process of curbing their use and is poised to join 101 other countries that have ratified the Kigali Amendment since it was first adopted by an initial group of 20 nations.

Zaelke noted that French President Emmanuel Macron held meetings at last year’s G-7 summit to ensure that both China and India moved ahead with plans to curb their use of these super-pollutants. “On the global level, the world has moved ahead on the Kigali Amendment,” Zaelke said.