Last year, Massachusetts legislators approved a pilot program to let 10 cities and towns ban fossil fuels in new buildings. Now, lawmakers and advocates are urging the state to streamline how municipalities participate and let them start doing it — soon.

“It's important that state government permit the towns that want to do this to go forward as quickly as possible,” state Sen. Mike Barrett told GBH News. “The Legislature wrote this language because a handful of towns had already moved way out in front. The communities had gone through the laborious process of drafting local bylaws and ordinances.”

The state’s Department of Energy Resources released draft regulations and a model rule at the end of December, soliciting public comment up through last week. The law mandates that, for participating communities, both new construction and major renovations would have to be fossil fuel–free operations, with some exceptions for settings like research labs and hospitals.

Under DOER’s proposed regulations, municipalities that have already asked the state for permission to ban fossil fuels in new construction, via a home-rule petition sent to Beacon Hill, would need to wait until early 2024 at the earliest to implement their bans.

It “proposes to delay the entire process much longer than the Legislature ever imagined,” Barrett said.

Many are impatient to get the ball rolling after then-Gov. Charlie Baker signed the legislation last summer, which will go into effect July 1. In addition to moving up the timeline, some lawmakers worry about red tape baked into the DOER’s drafts that could create a stop-start process as each municipality vies for state approval, one by one. Advocacy groups also raised broader concerns that restricting the pilot program to just 10 communities could create problems of its own: holding the state back in meeting its energy goals, and deepening inequity because many of the first cities and towns to apply for this program are wealthy municipalities.

“The Department of Energy of Resources appreciates all comments and will take them into consideration as it works to finalize regulations for the Municipal Fossil Fuel Free Building Demonstration Program and implement them as quickly as practicable,” wrote Danielle Burney in an email, a spokesperson for the Executive Office of Energy and Environmental Affairs, which oversees the DOER.

The law requires that the first 10 cities and towns to send home-rule petitions to the State House should get priority to participate.

But at least some of those first 10 communities will likely not be able to take part because of legislative guardrails on the program. Worried about stymying new construction in municipalities where affordable housing is already in short supply, the law requires all participants to either meet an affordable housing threshold or certain zoning code requirements.

Arlington, for one, is first in line for the project — but it falls below the state’s affordable housing threshold. Talia Fox, the town’s sustainability manager, is confident Arlington will ultimately qualify for the project and that it plans to modify its zoning bylaws.

“And we’ve designed the timeline of that process so that we are eligible to participate in the fossil fuel–free demonstration project,” she told GBH News.

Those who ultimately do not qualify will be able to withdraw from the program to make way for other cities and towns to take their place.

State Rep. Mike Connolly represents both Cambridge and Somerville on Beacon Hill. While Cambridge is one of the first 10 communities and has a spot in the program, Somerville was the 11th to submit its petition to the Legislature. City and state officials who represent the city are pushing the DOER to include it in their program, and speed up the evaluation of ”substitute” communities who do not fall in the prioritized group.

“I want to strongly urge DOER to consider both prioritized communities and substitute applications on a rolling basis,” Connolly wrote. “Our legislative intent was to establish a demonstration program that could effectively be used to collect data and prove the viability of the fossil fuel free building concept, and the value of the program will be enhanced if we can get to a place where a full set of ten participating municipalities are all able to get going with the program as quickly as possible.”

Soon after Somerville filed its petition, Boston did the same, asking the state for permission to ban new fossil fuel hookups. A 2021 city report found that 69% of Boston’s emissions come from buildings.

Electric companies like National Grid also pointed to the need for clarity on what demands each new all-electric development will put on the electric grid. The company suggested, in a written comment, that customers “should be required to consult with their local electric distribution company to ensure that the local electric system infrastructure is equipped to accommodate alternatives to fossil fuel on a case-by-case basis.”

Other advocates say the state needs to allow more municipalities to go fossil fuel free, a change that would have to come from the Legislature.

Lisa Cunningham is the co-founder of ZeroCarbonMA and has pushed for Brookline to ban fossil fuel hookups for years. She pointed out that many of the “substitute” communities hoping for approval — such as Boston and Somerville — represent a huge part of Massachusetts’ population and have much larger poor and minority populations. Northampton, meanwhile, is the only community in Western Massachusetts that is looking to take part.

“It really seems counterproductive to limit the number of communities in this pilot program, arbitrarily limit them to 10 communities,” Cunningham said. “It's not fair, from an equity point of view, really — it's not fair from an environmental justice point of view — to allow all these relatively wealthy communities to have first-come, first-serve at this program and then to exclude these other communities.”

Logan Malik, the interim executive director of the Massachusetts Climate Action Network, agreed.

“We know that the future is electric. We know that we will need to electrify our buildings, and communities across the commonwealth deserve the right, the opportunity, to decide for themselves,” he added.

Much of Massachusetts’ fossil fuel hookup debate has centered on Brookline for the past several years. The town passed local rules that would ban fossil fuels in new construction — twice — but they were halted by then-Attorney General Maura Healey, who said there needed to be action at the state level for such a change to legally go forward in Massachusetts. Brookline is one of the 10 communities that will be eligible to participate in the pilot program.

Barrett argues that urgency is essential, beyond the impacts of just the first 10 cities and towns, because the hope is that data gathered from the pioneering communities will help create a roadmap forward for how to meet the state’s ambitious climate goals.

“The additional delays anticipated by the draft regulation mean that we will remain in the dark about how to move forward on our climate strategy for additional months,” the senator said. “We’re hoping the state hears us and hastens the process along.”