The state Assembly voted Thursday to approve a bill that would loosen development permit requirements on some Wisconsin wetlands.

The proposal would allow developers to fill wetlands without a permit from the state Department of Natural Resources in some cases.

Four Republicans joined all Democrats in the Assembly in voting against the measure. The vote was 58-39.

"It’s been said that this is the worst bill for sportsmen in a generation — and that’s because wetlands are some of the most important habits for fish and wildlife," said state Rep. Nick Milroy, R-South Range, before the vote.

A number of environmental groups oppose the bill.

State wetlands make up about 20 percent of the wetlands in Wisconsin, which amounts to about 1 million acres. The rest are federal wetlands, which are regulated by the federal government.

Supporters of the measure say current state permitting requirements are too burdensome for businesses.

"This bill just sets up a streamlined process," said Rep. Jim Steineke, R-Kaukauna, the bill’s sponsor. "No high quality wetlands will be filled in because of this bill."

The Wisconsin Transportation Builders Association, Wisconsin Realtors Association, Wisconsin Manufacturers and Commerce, and a number of other industry groups support the plan.

After contentious public hearings on the bill, lawmakers amended it to protect "rare and high quality" wetlands.

"I can’t emphasize enough how much this bill has changed from the original," Steineke said.

Under the amendment, wetlands near some trout streams and those that are at least 75 percent representative of certain types of wetland, including a coniferous swamp or floodplain forest, would still be subject to permitting requirements.

But some environmental groups remained opposed to the bill, even after those changes.

George Meyer, of the Wisconsin Wildlife Federation, acknowledged the bill was trimmed to effect fewer wetlands, but argued it would still be detrimental to the state.

"The amended bill would still lead to the filling in of tens of thousands of acres of wetlands and thereby the loss of a significant amount of wildlife habitat," Meyer said via email.

Under the bill, permits wouldn't be required for filling wetlands less than one acre in size that are near populated areas and less than three acres in rural areas. It would also eliminate permit requirements for man-made artificial wetlands.

Current wetland mitigation requirements would also be waived, unless the wetland affected is larger than 1.5 acres and is outside an urban area.

The bill now moves to the state Senate.

Senate Majority Leader Scott Fitzgerald, R-Juneau, has said he is optimistic the bill will be approved there.

The Assembly also approved proposals Thursday that would:

Editor's Note: This story was updated with additional information from WPR at 9:30 p.m. Thursday, Feb. 15, 2018.