Maine regulators have once again cleared the way for an expansion of the state-owned landfill, the latest chapter in the legal tug of war that pits Maine’s waste disposal needs against the environmental rights of the Penobscot Nation.

The Maine Department of Environmental Protection issued its revised public benefit determination Monday, approving a 61-acre expansion of the Old Town facility that is 2 miles from the Penobscot Reservation at Indian Island.

The move follows a legal challenge that saw a Penobscot County Superior Court judge temporarily halt the project in January, ordering regulators to “more thoroughly” consider the cumulative environmental impacts on the tribe.

The expansion is slated to create 12 million cubic yards of additional landfill capacity, extending the life of a facility that handles about 52% of all waste landfilled in Maine. But the approval comes with a set of conditions that must be met.

For the first time, the DEP is requiring a landfill operator to design and build a special treatment system to remove harmful forever chemicals, or PFAS, from landfill runoff, also called leachate, before the expansion can begin operations.

Tribal and environmental advocates say the ruling still fails to protect the community and ignores the cumulative pollution, history and harm that the Superior Court judge ordered the state agency to factor into its decision making.

“DEP has once again treated environmental justice as a checkbox rather than a commitment to the people the law was meant to protect,” said Nora Bosworth, a staff attorney at Conservation Law Foundation.

The 8,500-square-mile Penobscot River watershed is burdened by a long history of industrialization. Tribal members have for years been advised to limit how much fish they eat from the river due to legacy contaminants.

Tribal Chief Kirk E. Francis said Monday that the Penobscot Nation has worked hard to address the harmful impact on the health of the Penobscot people, the lands and the river itself, which it considers to be its oldest citizen.

“This decision does not reflect the lived reality of our people,” Francis said. “Our voices and our knowledge of this place must be meaningfully considered when those in power make decisions that will impact our land and community.”

The DEP maintained that the expansion — a modern, fully lined facility — would not “unduly burden” the community given the new safeguards, including stricter limits on the volume of sludge and construction debris the landfill can accept.

The order also requires the operator, a subsidiary of Casella Waste Systems, to fund a third-party odor consultant and establish a near real-time alert system to notify local residents of “significant landfill events.”

State planners have argued that without the expansion, Maine will run out of landfill space within the decade. While Maine moves forward, the Penobscot Nation and the Conservation Law Foundation are reviewing the latest decision to determine whether they will appeal again.