Maine regulators on Tuesday approved the $71.9 million acquisition of Bangor Natural Gas Co. by Unitil Corp., the state’s largest gas utility. As part of the deal, Unitil will have to measure, report and take steps to reduce the amount of greenhouse gases released into the air from accidental leaks and intentional venting of pipelines.

The Public Utilities Commission voted 3-0 to back the sale announced in July. The acquisition boosts Unitil’s 618-mile distribution network in Maine by more than 50%, adding Bangor Natural Gas’ 351 miles of pipelines. The move also will join the 8,500 Bangor Natural Gas customers with Unitil’s 33,000 Maine customers. Unitil, known as Northern Utilities, is based in New Hampshire and also serves customers there and in Massachusetts.

Bangor Gas has been acquired from PHC Utilities Inc., a subsidiary of Hope Utilities Inc. of Morgantown, West Virginia. A closing date has not been set while Unitil awaits the formal order issued by the PUC, Unitil spokesman Alec O’Meara said. Hope Utilities did not respond Thursday to a telephone message seeking information about the deal.

Public Advocate William Harwood has said the move could save money for ratepayers by consolidating the state’s relatively small natural gas industry, leaving three natural gas companies operating in Maine.

The acquisition agreement approved by the PUC stipulates that Bangor Gas will not seek a rate increase before Jan. 1, 2027, and will not bill customers for certain costs related to the deal.

PUC Chairman Philip L. Bartlett II said the provisions barring a rate increase for two years and limiting the impact on ratepayers of business reorganization costs protect consumers. And the provisions to measure and mitigate natural gas emissions are “beneficial and in the public interest,” he said.

Unitil reported that 20,424 metric tons of carbon dioxide equivalent, or the amount of gas that would have the equivalent global warming impact, were released in 2023. It’s down by about 18% since 2019. Construction work and reported leaks are leading causes of gas releases, O’Meara said.

Unitil said it’s using gas-capturing technology as part of regular maintenance to prevent gas releases from blowdowns, which are releases of pressurized natural gas during maintenance, inspections or emergency responses, and other construction activities.

Harwood, Unitil and the Conservation Law Foundation, an environmental group, negotiated an agreement requiring Bangor Gas and Unitil to review emissions mitigation practices, including from leaks and intentional venting, and review “commercially reasonable ways” to improve those practices.

O’Meara said the procedures are in place in its network of gas pipelines in the Portland area and will be applied to its new Bangor Gas property that serves customers in Hancock, Penobscot and Waldo counties. Unitil’s service area extends from the Maine-New Hampshire line to Lewiston.

The agreement will not be interpreted as justifying Bangor Gas to replace pipelines as a way to comply with the agreement. At the same time, the agreement will not be interpreted to constrain the “operational discretion” of the gas business.

Unsuccessful legislation this year tried to limit natural gas connections by changing how hookups are financed. The measure would have required prospective businesses and residential customers, rather than ratepayers, to pay for natural gas expansions. Supporters said the legislation would limit greenhouse gas emissions and slow the expansion of natural gas pipelines as policymakers are pushing for broader electrification of building heating and cooling systems.

Natural gas is typically used for heating water and buildings, cooking and drying clothes.

Maine’s natural gas utilities, which include Summit Natural Gas of Maine and Maine Natural Gas, serve 50,000 customers, which is a relatively small number, he said. The 8,500 Bangor Natural Gas customers is “really small,” he said.