BOSTON (State House News Service) – Lawmakers were unable to find agreement on a bill aimed at maintaining open spaces across Massachusetts in a marathon final formal session Sunday into Monday, but one top negotiator said he remains hopeful the measure can still pass in the coming months.

Sen. Sal DiDomenico, one of the leads on a conference committee that failed to produce an accord by the time the Legislature shifted to an easygoing mode for the remainder of the 2021-2022 session, told the News Service he does not believe the proposal died with the final gavel.

“My goal is to get this done during informal,” the Everett Democrat said Tuesday. “We’re very optimistic that we can come to a resolution. We made some progress during the last couple of weeks.”

DiDomenico and his House counterpart, Rep. Ruth Balser of Newton, are tasked with finalizing legislation that would enshrine in state law a longstanding executive branch practice to balance any release or conversion of protected public land with the addition of newly protected land.

Under legislative rules, both branches are set to meet only in informal sessions until the 2023-2024 term begins in January. A single lawmaker’s objection can stall any bill during an informal session, but if legislative leaders secure unanimous consent, most proposals can still advance to Gov. Charlie Baker’s desk.

“You never say never, right, but I don’t anticipate anything standing in the way if we can come to a resolution in the two branches,” DiDomenico said. “I spoke to my co-chair, Rep. Balser, and I know the Senate conferees are also on the same page that we want to try to get something done during informal. We’re all on the same page trying to find a solution here.”

Article 97 of the state Constitution, which voters approved in 1972, empowered the Legislature to order purchase or acquisition of land for conservation, recreation or open space purposes, and it set a requirement that releasing any property from those protections must be done with a two-thirds vote.

Since 1998, the Executive Office of Energy and Environmental Affairs has generally had a “no net loss” policy, which calls for the state to match any land the Legislature removed from conservation restrictions with an equal or greater replacement, according to Massachusetts Land Trust Coalition Executive Director Robb Johnson.

Johnson said that policy has been enforced to varying degrees over the years, with a “relatively consistent” focus in the past decade-plus.

Environmental advocates have long pushed to enshrine the measure in state law and decouple it from the discretion of the governor and their deputies, and this session was the first time both branches approved a bill, Johnson said.

“We’ve all been enormously excited about this opportunity to get it across the finish line, and thus we’re quite disappointed that no report was issued by the conference committee,” Johnson said in an interview.

The House and Senate bills (H 851 / S 2831) both seek to make “no net loss” permanent law, but they vary in one major feature. The Senate version allows use in some instances of what Johnson called a “cash in lieu alternative” to a replacement land conservation, which is a payment designed to fund purchase of additional land at a later date if state officials decide there is no appropriate parcel to conserve when they lift restrictions on another piece of land.

Advocates have previously voiced support for the House version of the bill, which did not feature a cash in lieu option, warning that the payment language could hamstring the goal of no net loss by delaying replacement conservation moves or incentivizing removal of restrictions.

On Tuesday, as they pushed for lawmakers to find consensus during their upcoming stretch of informal sessions, Johnson and representatives from nearly a dozen other groups signaled that they would be open to a cash in lieu policy if it featured “strong and specific constraints.”

“We urge lawmakers to finalize this important legislation this year, crafting a bill that is true to the intent of Article 97, enhances transparency and accountability in the administration of the No Net Loss policy and, most of all, honors the public demand to protect precious parks and conservation land,” the groups said in a joint statement.

Unlike some of the higher-profile bills on their agendas, legislative leaders took their time sending the open space preservation proposal into the formal negotiating arena of a conference committee. The House approved its version of the bill with an unrecorded voice vote on July 28, 2021 without any debate, and the Senate advanced its version in April — nearly nine months later — on a unanimous vote.

It took another three months before the House and Senate named conferees to try to finalize a version, giving the panel a bit more than two weeks in which to work ahead of the Legislature’s self-imposed July 31 deadline to complete formal business.

As late as Sunday afternoon, Balser said talks were “very active,” but negotiators did not reach agreement even as legislative leaders stretched session more than 10 hours beyond the midnight deadline to allow themselves to finalize other massive bills legalizing sports betting, improving access to mental health services and reforming the state’s gun laws in response to a U.S. Supreme Court decision.

“These talks are very fluid, as you know, and it can go back and forth. Obviously, there were a lot of things happening at the same time, so we were all trying to get things resolved. There wasn’t a point where we said we’re just going to stop this,” DiDomenico said. “We weren’t able to find common ground on a couple of things, and it’s kind of just — time ran out on us. It was the nature of the time we were working in.”

Balser’s office could not be reached for comment Tuesday. The other conferees are Reps. James O’Day and Susan Gifford and Sens. Jamie Eldridge and Ryan Fattman.

“We certainly felt like there was ample time for negotiations to take place, so we were in fact dismayed, disappointed and frustrated to see that they couldn’t reach a conference report in the time allotted,” Johnson said. “Obviously, they had a lot of other issues on their plate, so we’re sympathetic, but we’re definitely frustrated.”