AUGUSTA, Maine — A legislative committee unanimously endorsed a plan to ban the controversial chemical bisphenol-A, or BPA, on Friday in what some supporters are describing as a significant policy defeat for the LePage administration.

The Environment and Natural Resources Committee’s vote followed weeks of vocal backlash against Gov. Paul LePage over his stated opposition to a ban on a chemical that environmental and health groups say could cause serious health problems, particularly in children.

After a lengthy review, Maine’s Board of Environmental Protection voted in December — during the final weeks of Gov. John Baldacci’s administration — to ban the sale of food and beverage containers containing BPA beginning in 2012. But the ban was subject to legislative approval, and the incoming LePage administration has come out against regulatory action on BPA.

On Friday, the administration appeared to soften its stance by not opposing the ban in committee. The issue now heads to the full Legislature for consideration.

“It’s a major political defeat for Gov. LePage, and lawmakers did the right thing by standing with Maine moms and doctors in protecting children’s health,” said Mike Belliveau, executive director of the Environmental Health Strategy Center.

The political debate over regulating toxic chemicals is not over yet, however. In addition to more votes on the BPA ban, lawmakers on the same committee will consider a bill to rewrite key provisions of the law that allows the state to ban consumer products that contain certain chemicals.

“That will be the bigger fight,” said Rep. Robert Duchesne, a Hudson Democrat who serves on the committee. “We will see where we end up.”

BPA is a chemical additive commonly used in hardened plastics — such as baby bottles and children’s sippy cups — as well as in the liners of tin cans and some paper products.

Proponents of a ban said a growing mountain of scientific studies — most conducted on animals — suggest a link between BPA and learning disabilities, reproductive problems, cancer and obesity. Critics claim the chemical, which can mimic or disrupt hormones, is particularly dangerous to children.

Nine states plus Canada already have taken steps to restrict the use of BPA in consumer products, and many manufacturers are voluntarily dropping the chemical. But representatives of the chemical industry and other product manufacturers cite other scientific studies and governmental reviews maintaining that BPA is safe.

About a dozen people stood in front of a 20-foot-tall inflatable baby bottle outside of the State House on Friday to urge lawmakers to support a ban that they said will help parents make smarter and healthier decisions. About two dozen people then testified in committee in support of the ban.

“Plastics are not required to have labels, so it is very difficult for consumers to make informed purchasing decisions,” Urvashi Rangan, director of technical policy at Consumers Union, the publisher of Consumer Reports magazine, told the committee. “This law actually creates a safe haven so consumers don’t have to do such guess work.”

In earlier statements, LePage said he has yet to see enough science to support a BPA ban and that Maine should wait for the U.S. Food and Drug Administration to act. He also angered ban proponents by quipping in February that exposure to BPA would, at worst, cause some women to grow “little beards.”

But on Friday, the administration appeared to backtrack from its earlier opposition — at least somewhat.

Darryl Brown, commissioner of the Maine Department of Environmental Protection, testified neither for nor against the proposal although he did express concerns about the process that led up to the ban as well as using regulations to remove chemicals from consumer products.

“There are many other tools and options we can use as a regulatory agency and we frankly don’t wish to pursue sales prohibitions as a mechanism,” Brown told lawmakers. “We support scientific inquiries into the examination of safer alternatives … and we believe the marketplace is already moving towards safer alternatives” to BPA.

Brown told lawmakers that, although not speaking for LePage, he had sent the governor a copy of the department’s position and had not received any “adverse comments.”

Pressed by reporters for clarification on the governor’s stance, LePage’s office released the following statement Friday evening: “Governor LePage continues to believe, absent consensus science supporting product prohibitions, the BPA rule developed by the last administration should not go into effect. Market forces are giving consumers the chance to make their own choices and that would have been the approach of the LePage administration.”

Several trade organizations representing manufacturers that had testified against the ban before the Board of Environmental Protection also testified neither for nor against the bill on Friday.

Several lawmakers and other individuals involved in the debate attributed the shift away from outright opposition to a recognition that, given the recent public outcry and media attention, opposing a BPA ban wasn’t a smart political move.

“I believe there has probably been behind-the-scenes discussion about what is the right fight to pick,” said Duchesne, the Hudson lawmaker.

Still, BPA had its defenders on Friday.

Steven Hentges with the American Chemistry Council, an industry trade group, described BPA as one of the best-studied chemicals on the market.

“That science has been comprehensively reviewed by quite a few governmental bodies around the world in recent years … and there is indeed a consensus among those governmental bodies that BPA is not a risk to human health,” Hentges said.

Other testimony on Friday hinted at the coming fight over the law — known as the Kid-Safe Product Act — that established the process to ban BPA and other chemicals deemed to be a threat to public health. That law passed with unanimous support in the Senate and overwhelming support in the House in 2008.

The Environment and Natural Resources Committee will hold hearings next Tuesday on a bill, LD 1129, that would rewrite aspects of the law. The bill is sponsored by committee co-chairman Rep. James Hamper, R-Oxford.

Brown said the LePage administration believes the list of 1,700 chemicals slated for review needs to be narrowed and that the focus of the law should be on products marketed to and used by children. The law needs to be clearer and more predictable, Brown said.