The Massachusetts-based Conservation Law Foundation is appealing the state Department of Environmental Protection's April decision to allow a controversial ash landfill in Saugus to continue operations. The appeal follows a similar one filed last week by the Saugus Board of Health.

The landfill is owned and operated by Wheelabrator, which uses it to store ash from a garbage incinerator on the site that burns 1,500 tons of garbage per day from 10 Massachusetts communities and turns it into electricity.

The landfill has been the target of criticism by environmental groups and neighboring community members. It was originally supposed to have closed 22 years ago, but Wheelabrator has received extensions from the Massachusetts Department of Environmental Protection (DEP). The company applied to open up part of the landfill, giving them 400,000 cubic yards where they can put more ash.

WGBH News covered that proposal in March. It was approved by the DEP in April.

Neighbors and environmentalists have argued that the site doesn't have a state-of-the art plastic liner designed to keep contamination from escaping. And they worry that leaking contamination could affect the surrounding salt marsh and might be harmful to the health of those in neighboring residential communities.

“The Wheelabrator landfill is the most dangerous in Massachusetts, and it is putting the health of nearby residents at risk,” said Kirstie Pecci of the Conservation Law Foundation in a written statement announcing the appeal.

The appeal says Wheelabrator never obtained a required site assignment permit from the Saugus Board of Health.

“The local site assignment process ensures that the people who are directly affected by this expansion are heard," Pecci said. "For that reason, state law grants the Saugus Board of Health ultimate authority over waste facilities in the town. Until the board determines whether the landfill is a potential danger to public health and safety as well as the environment, MassDEP legally cannot allow this project to move forward.”

In a written statement, James Connolly, vice president of environmental, health and safety at Wheelabrator Technologies calls the project an "integral part of the state’s environmental and economic infrastructure," and he emphasizes that the plan approved by the DEP does not change the landfill's height, footprint or "lateral measurement."

"The MassDEP’s decision followed a rigorous, thorough and transparent process that lasted nearly a year, and included multiple public hearings and a comment period during which three-quarters of the 1,800 comments submitted supported Wheelabrator," the statement reads. "The department considered all the technical issues associated with our operations, answered all public questions with thoroughness and specificity, and concluded that the monofill is safe and sound."

Connolly goes on to call the appeals "unfortunate," calling out the town board of health's appeal as particularly detrimental to the town.

"Just last year, the town spent taxpayer dollars to unsuccessfully defend its attempt to use the zoning process to close Wheelabrator Saugus — an action the state attorney general deemed unlawful and overturned," he said. "We remain open to a dialogue with the town about a long-term plan for Wheelabrator Saugus that will enhance our economic and environmental value to the community."

The DEP says it is currently reviewing the letter notifying the department of the appeal, and had no comment at this time. At the time of the approval, DEP spokesman Ed Coletta said in a statement: “The Massachusetts Department of Environmental Protection takes seriously its responsibility to protect public health and nearby resource areas, and following a comprehensive stakeholder process and review of Wheelabrator Saugus’ ash landfill permit application, has issued a permit that provides some short-term disposal capacity without increasing the size or height of the facility, ensures current environmental and containment systems operate properly and directs $2.5 million to repair a nearby abandoned landfill site.”