THE BAKER ADMINISTRATION late Friday night approved a key environmental impact report for the proposed Wynn Resorts casino in Everett and said broader traffic concerns raised by Boston Mayor Marty Walsh and Attorney General Maura Healey should be addressed through a regional working group led by state officials.

Matthew Beaton, the state secretary of energy and environmental affairs, said in his 27-page decision that he gave serious consideration to ordering more planning to deal with traffic congestion in and around Sullivan Square but ultimately concluded that Wynn had met the requirements of the state’s environmental policy act.

“I have concluded that the practical, rational, and effective approach to addressing broader regional transportation impacts for this project is through enhanced transportation planning processes, not through the prism of this single project,” Beaton wrote. Beaton issued his decision at 8:37 p.m.

Beaton said the purpose of the regional working group — first proposed by Beaton’s colleague in the Baker cabinet, Transportation Secretary Stephanie Pollack — is to “assess and develop long-term transportation improvements that can support sustainable redevelopment and economic growth in and around Sullivan Square. Wynn Everett has committed to participate in the regional working group and provide a proportionate share of funding to support this effort.”

Beaton said the group would be led by the state Department of Transportation and would include officials from other state agencies; the communities of Boston, Everett, and Somerville; and large employers in the area.

Wynn still needs to obtain a host of permits from state and local agencies before construction of its $1.7 billion hotel and casino can begin, but the project cleared a major hurdle with the Baker administration’s decision. Wynn Resorts had sought and failed to win state environmental approval for the project twice before, and faced fierce opposition in its latest attempt from Walsh and Healey.

Healey wanted a new independent study conducted on the project’s regional traffic impacts, which was opposed by the Baker administration. She also charged that Wynn was being allowed to play by a different set of rules as it went through the review process, but Beaton said the methodology used by his agency was no different from what was used in assessing other casino proposals.

Walsh insisted the casino is incompatible with the city’s plans for Sullivan Square and he also demanded that Charlestown residents be allowed to vote on whether the casino should be built. The mayor is suing the Massachusetts Gaming Commission in a bid to overturn the license award to Wynn.

In a statement issued Friday night following Beaton’s ruling, Walsh said he would continue his fight but seemed more focused on making the best of what he considers a bad situation. “We will continue to fight for the best interests and public safety of the people of Charlestown – where the effects of the proposed casino would be enormous,” he said. “Secretary Beaton’s decision today could make it necessary to invest well over $175 million in Sullivan Square and Rutherford Avenue. I will work with the Baker administration and my colleagues in federal and state government to ensure that adequate funding mechanisms are in place for a regional project of this magnitude. We will also coordinate with these partners to push for an accurate and expert-based transportation plan in order to fully understand and then mitigate this development’s impacts on Boston’s streets.”

Wynn has set aside $25 million for a long-term solution to Sullivan Square congestion and another $11.9 million has been provided by the federal government.

Healey, a Charlestown resident who is opposed to casino gambling, issued a statement that was hopeful yet contained a warning. “I continue to believe that a long-term plan to solve the traffic problems in Sullivan Square and Rutherford Avenue is critically important and should be in place before a casino is built,” she said. “I am hopeful that the many stakeholders involved will follow through on their promise to find a solution. My office has a responsibility to hold the gaming industry accountable for its commitments and we will continue to do all we can to protect the people of Massachusetts.”

The attorney general theoretically could challenge Beaton’s decision in court, but she indicated in an earlier interview that she was not enthusiastic about pursuing that route. “I’m trying to deal with this not through a litigation lens,” she said. “Let’s all come to the table and get this right, and make it work. We’re in the midst of an imperfect process and now’s the time to make it work.”

In his decision, Beaton said Wynn had addressed other concerns he had raised in rejecting the company’s previous environmental impact report. He noted that state officials had concluded Wynn’s $6 million purchase of three small MBTA parcels of land adjacent to the Everett site would not impact T bus repair operations there. He also noted Wynn had agreed to provide $7.4 million over 15 years to subsidize more frequent Orange Line train service.

Steve Wynn issued a statement lauding Gov. Charlie Baker for his support. “We are gratified at this critical moment that we have moved much closer to the realization of creating a destination, grand hotel in Massachusetts,” Wynn said. “The process has been meticulous and hard fought and undoubtedly will continue to be so. However, with the support of the governor and his administration, the process was open and fair.”

The Gaming Commission also hailed the approval and said it would “encourage Wynn to work cooperatively with the neighboring communities, and will use its authority to ensure that Wynn continues to work with other state and local agencies and permitting authorities to develop solutions to outstanding issues. We are particularly mindful of the criticality of the long-term solution to Sullivan Square, as envisioned in our original conditional license award and the $25 million commitment to that project that we required of Wynn.”

Bruce Mohl oversees the production of content and edits reports, along with carrying out his own reporting with a particular focus on transportation, energy, and climate issues. He previously worked...