Three Democratic senators from the U.S. are urging the Trump administration to clarify how it assessed a proposed regulation aimed at removing habitat protections for endangered and threatened species, and whether industry influenced its creation.

Senators Adam Schiff, Sheldon Whitehouse, and Cory Booker submitted a letter on Monday to the Interior and Commerce departments inquiring about how the administration intends to safeguard species if the regulation is amended.

The debate centers on a long-established interpretation of “harm” within the Endangered Species Act, which has traditionally covered the alteration or destruction of habitats, recognized as the leading cause of extinction.

Last month, the U.S. Fish and Wildlife Service and National Marine Fisheries Service proposed a rule that says habitat modification shouldn’t be considered harm because it isn’t the same as intentionally targeting a species, called “take.” Environmentalists argue that the definition of “take” has always included actions that harm species, and the definition of “harm” has been upheld by the U.S. Supreme Court.

Under the new interpretation, industry, developers and others could simply say they didn’t intend to harm an endangered species, environmentalists say, which could lead to the extinction of critically endangered species like the Florida panther and spotted owl.

The proposal could threaten progress made to save species that once were endangered, including bald eagles, gray wolves, Florida manatees and humpback whales, they said.

The senators said it “represents an end run around the Endangered Species Act.”

“It is widely understood that a species cannot live without a safe place to call home,” the letter reads.

They also asked the administration to explain how it could enforce the act at all amid efforts by Elon Musk’s Department of Government Efficiency to fire federal staff and cut agencies’ funding.

The proposal is in the middle of a 30-day public comment period. Environmentalists have vowed to challenge it in court if it’s adopted.

The departments of Commerce and Interior did not immediately respond to emails sent Monday seeking comment.

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