United Nations ? The Obama administration, in a major environmental policy shift, is leaning toward asking 195 nations that ratified the U.N. ozone treaty to enact mandatory reductions in hydrofluorocarbons, according to U.S. officials and documents obtained by The Associated Press.

“We’re considering this as an option,” Environmental Protection Agency spokeswoman Adora Andy said Wednesday, emphasizing that while a final decision has not been made it was accurate to describe this as the administration’s “preferred option.”

The change — the first U.S.-proposed mandatory global cut in greenhouse gases — would transform the ozone treaty into a strong tool for fighting global warming.

“Now it’s going to be a climate treaty, with no ozone-depleting materials, if this goes forward,” an EPA technical expert said Wednesday, speaking on condition of anonymity because a final decision is pending.

The expert said the 21-year-old ozone treaty known as the Montreal Protocol created virtually the entire market for hydrofluorocarbons, or HFCs, so including them in the treaty would take care of a problem of its own making.