The Puerto Rico debt bill is quickly spilling over into an environmental policy debate, as a coalition of environmental and conservation groups hope to sway Democrats to block provisions that would harm wildlife sanctuaries on a small island off the shores of the U.S. commonwealth.

The House's draft bill to solve the territory's soaring debt also would convey the island of Vieques back to the Puerto Rican government, which the green groups say would place in jeopardy the wildlife sanctuary there that currently falls under the authority of the Department of Interior.

The Puerto Rico debt bill would eliminate environmental review for large-scale projects and make litigation opposing any project under the National Environmental Policy Act unwarranted, the coalition says.

"On behalf of our millions of members and activists we write to urge you to strongly oppose two environmentally damaging provisions in the draft legislation," the coalition of almost two dozen groups said in a letter to the Fish and Wildlife Service on Monday.

"The first, Section 411, aims to take thousands of acres of the Vieques National Wildlife Refuge away from the American people thereby placing nationally protected endangered species habitat under threat of bulldozers and development and encouraging efforts to sell off public lands for private gain," the letter reads.

"The second, is Title V of the draft legislation which eliminates citizen input, public scrutiny, environmental review, and limits judicial review under the National Environmental Policy Act (NEPA) for large-scale projects chosen by an unelected board," the letter adds.

"We urge you to oppose these provisions and work to remove them" from the House draft legislation, the letter reads.

The Puerto Rico bill is slated for its first hearing on Wednesday before the House Natural Resources Committee.

The top Democrat on the committee, Rep. Raul Grijalva of Arizona, is expected to raise the concerns over Vieques, but his office did not respond to requests for comment.

It is not clear if the Vieques concerns will become a top issue for Democrats when the bill comes up later this week.