The increasingly political fight over plans to build an Amtrak maintenance facility near a Brunswick neighborhood ratcheted up a notch this week when the commissioner of Maine’s Department of Environmental Protection moved to take personal oversight of the project’s approval.

Commissioner Patricia Aho sent a letter to Amtrak requesting information on the project and directed the Northern New England Passenger Rail Authority, which oversees passenger rail services in Maine, to send any correspondence with the DEP about the project to her office.

“Following a July 30 meeting with NNEPRA, the department has raised a number of questions that need responses to ensure that all environmental standards are met, and outlined those questions in an August 27 letter to NNEPRA,” Aho said in a statement. “The department is committed to the protection of the environment and public health and will carefully review the answers to our concerns.”

Among the questions Aho wants answered:

How will oil storage tanks be handled on site?

How will chemicals and septic waste be disposed?

How long will trains idle at the facility’s entrance?

Will the level of storm water runoff be acceptable given high concentrations of lead and arsenic on the proposed site?

Aho’s letter was sent Wednesday to the rail authority with another letter from the manager of the DEP’s land resources regulation project that rejected the authority’s storm water management permit. A Superior Court judge already had rejected the storm water permit two months ago because of insufficient notification of abutters, which forced the authority to resubmit.

The recent setbacks have delayed construction of a $12 million, 60,000-square-foot layover facility between Church Road and Stanwood Street, and that’s just fine with local residents.

“We’re happy that the state has become more engaged in this process and is listening to our concerns,” said Bob Morrison, president of the Brunswick West Neighborhood Coalition.

Patricia Quinn, executive director of the rail authority, said the recent correspondence from DEP was “a little unexpected,” but said the authority has been working closely with the state agency to address any concerns.

“They have done a thorough job and should be commended,” she said. “But a vast majority of their questions already have been resolved or explained and if there are additional adjustments to be made, we can do that as well.”

Ever since the layover project was announced in 2011 as a necessary component of Amtrak’s extension of its Downeaster train service to Brunswick, neighborhood residents have complained about the potential impacts, including noise and environmental concerns.

Morrison said residents’ complaints have failed to gain any traction with rail authority officials.

State Sen. Stan Gerzofsky, a Democrat from Brunswick who has criticized the proposed layover facility, said the authority, a state agency, has been “dictatorial” in its decision making.

“They have refused to truly evaluate any other location,” he said. “But I think we really need to know the environmental impact of erecting this kind of facility in the middle of a town and the middle of a neighborhood.”

Aho’s boss, Gov. Paul LePage, weighed in on the project months ago.

In a March letter to the Federal Railroad Authority, LePage outlined many of the same concerns voiced by residents. The governor also questioned whether other sites farther from residential neighborhoods were seriously considered.

U.S. Sen. Angus King last fall sent a similar letter to the federal authority urging a “full, fair and transparent” assessment of the project. King owns a home in Brunswick.

In June, after months of review, the federal agency concluded that the layover facility would have no significant environmental impact on the Brunswick neighborhood.

Nevertheless, the neighborhood coalition has continued to fight the project and has gained traction politically.

In July, a group of six Democratic Maine lawmakers criticized the Brunswick facility and suggested the rail authority look elsewhere, particularly somewhere along its core Portland-to-Boston route.

Quinn, however, said the layover facility in Brunswick is crucial to any expansion of Amtrak passenger service, either west to Lewiston/Auburn, north to Augusta, or northeast to Rockland.

“The construction cannot begin until the permit is issued, but we’re ready to move forward,” she said, adding that the authority and DEP officials could sit down as early as next week.

Not everyone approves of the politicalization of the process.

Wayne Davis, head of Trainriders/Northeast, a rail advocacy group that gathered 90,000 signatures in 1989 for a petition asking the state to restore passenger rail service in Maine, said the group historically avoids politics because it views train service as a nonpartisan issue.

But he said the LePage administration’s sudden strong interest in the permitting process for the layover facility might cause his group to organize rail activists to campaign against LePage in the governor’s race.

“We are not powerful, but it would be enough to put a bump in the road for someone who wants to get re-elected,” he said, adding that he thinks LePage is “tinkering with the most successful train in the nation.”

Staff Writer Tom Bell contributed to this report.