ELLSWORTH, Maine — In a split decision, the Maine Board of Environmental Protection voted Thursday to impose more stringent noise regulations on commercial wind turbines operating near homes or businesses.

But the new rules — which must pass muster with lawmakers before taking effect — appear unlikely to satisfy parties on either side of the debate over whether Maine’s rapidly growing wind energy industry is positive or negative for the state.

“At every level, we were not happy,” said Rufus Brown, an attorney representing the citizens whose petition forced the board to consider new rules regulating turbine noise. “But it still advances the issue and it gives us a framework for the future. It gives us more than we had before.”

BEP members voted 5-4 to approve new rules that lower from 45 decibels to 42 decibels the maximum allowable noise from wind farms between 7 p.m. and 7 a.m. as measured from houses and other “protected locations” within one mile of the turbines.

Additionally, the proposed rules lay out a detailed process for collecting sound readings and compiling noise complaints, all of which were lacking in the more than 20-year-old noise standards now applied to wind energy facilities.

Turbine noise has arisen as an issue at wind farms in the Aroostook County town of Mars Hill, in Freedom and most recently at a three-turbine facility on the island of Vinalhaven. In the latter case, several residents are suing the Department of Environmental Protection, alleging among other things that the department has failed to enforce the existing 45-decibel noise statute.

But despite increasingly vocal and well-organized opposition to commercial wind energy facilities in Maine, polls suggest that the push to harness the wind for electricity appears to enjoy strong support among most Mainers.

Forty-two decibels is far below the 35 decibels sought by the petitioners who argue noise, vibrations and “shadow flicker” from the 400-foot-tall turbines can affect the health of nearby residents as well as property values. But wind energy industry representatives had argued that the proposed rules were unnecessary and could create regulatory uncertainty in an industry that has invested roughly $1 billion in Maine in recent years.

“At a certain point, the industry has to say, ‘Is Maine open to wind energy industry or not?” said Jeremy Payne, executive director of the Maine Renewable Energy Association, an industry trade group. “The more frequently we make changes and adjustments, the more uncertainty is created in the industry.”

By voting to move forward with the rules, the five prevailing board members disagreed with a recommendation from Maine Department of Environmental Protection staff that the board hold one more public hearing on the issue.

Pending changes to the board appear to have played a role in that decision. Thursday’s BEP meeting was the final one for roughly half of the 10 board members and was the last gathering before the size and scope of the board is reconfigured as part of a regulatory review bill passed by the Legislature earlier this year.

While four board members supported sending the issue to a public hearing, those in the majority felt the board that has grappled with the issue for the past 10 months should make the decision.

“The board that would preside over that public hearing is not the same board that has dealt with this issue,” said Samantha DePoy-Warren, spokeswoman for the department.

Several board members also questioned whether an additional public hearing would yield any new information given the contentious nature of the issue, according to DePoy-Warren. Although department staff had wanted to solicit one more round of public comments, staff also believe the proposed rules will help to address noise concerns, she said.

“Forty-two decibels isn’t as stringent as some wanted and isn’t as lax as others wanted, but it is a good step in the right direction … and data submitted [during the hearing process] indicates it will result in a reduction in noise,” she said.

If approved by the Legislature, the 42-decibel limit will not apply to the wind energy facilities already operating in Maine because they were approved under different standards. They also will not apply to any projects approved before the rules take effect.

More than 50 people had requested that the board hold another public hearing on the issue. But critics of Maine’s wind energy facilities and industry representatives were divided on that issue as well.

Brown, the attorney for the petitioners seeking tougher noise rules on wind farms, said holding another public hearing would have been unfair to the homeowners and grass-roots groups that spent considerable sums preparing for the first hearing. He also suggested that the industry was hoping to find more support among the new board.

“We were very concerned that this was just a delay tactic to bring in people who were more pro-wind to the board,” Brown said.

But Payne said another hearing was merited given the substantive differences between the petitioners’ original proposal and the rule endorsed by the board on Thursday.

The proposed rules now go to lawmakers, who have the ability to change the proposal as well as hold a public hearing.