State regulators will be using an outdated rule to review a plan to close a heavily contaminated compost plant in central Maine, worrying environmentalists that the area and its surroundings will not be adequately cleaned up.
The rule, which was last updated in 2018, requires removal of compost and wastes and reducing soil contamination. It does not cover the cleanup of wetlands and ecosystems near Hawk Ridge Compost Facility in Unity Township that state tests have shown are contaminated with high levels of forever chemicals.
Since last year the state had been pressuring Casella Waste Systems, the $1.6 billion waste management company that owns Hawk Ridge, to conduct more testing and remediate the site. Instead, Casella decided to shut it down starting last September, citing regulations and high remediation costs. The Bangor Daily News was the first to report the planned closure.
Maine’s lack of up-to-date plans to close down such sites highlight the difficulty of keeping regulations up with the rapidly evolving scientific knowledge about PFAS. The state plans to start updating the rule this year, but that could take at least two years, stretching well beyond the planned Hawk Ridge shutdown at the end of June.
Hawk Ridge, the state’s largest composting facility, had for almost four decades accepted millions of gallons of sludge containing municipal and industrial waste and turned it into compost used on farmland in Maine and elsewhere. It stopped taking it in September after test results showed high levels of PFAS in sludge, compost, retaining ponds and land at the facility in the past few years. State tests also showed that high PFAS levels were detected at least eight miles downstream of Hawk Ridge.
The current rule governing closures is only three sentences long, requiring removal of compost, contaminated water and other residue. Companies also must put erosion control measures in place and “broom clean” structures and equipment.
But the location is so contaminated that it should be treated like a Superfund site with the Maine Department of Environmental Protection taking a broader approach to the cleanup, said Mike Belliveau, director of Bend the Curve, which advocates to reduce chemical pollution.
“This isn’t simply a shutdown of a waste management facility,” he said. “This is a site of serious environmental contamination.”
The rule may be sufficient for a clean compost operation, but Hawk Ridge is not clean, Laura Orlando, senior scientist at Just Zero, a waste reduction advocacy group, said. She said it is particularly striking that Maine is using a dated rule to oversee the closure of Hawk Ridge given the state’s national leadership on PFAS policy, including banning sewage sludge spreading on land as a fertilizer in 2022.
“If existing statutes do not provide clear authority to require testing, reporting and meaningful remediation at this PFAS-contaminated site and others like it, then Hawk Ridge exposes a significant policy gap,” she said.
Casella submitted its 70-page closure plan to Maine regulators on Jan. 16. The BDN obtained a copy of the plan last week. A Maine Department of Environmental Protection spokesperson said there is no statutory deadline for the agency to approve it.
The closure plan calls for removal of wastes, equipment and stormwater structures from the facility and cleaning all surfaces, including power washing the compost processing building roof and other paved surfaces. Casella plans to pump water from two contaminated ponds at the site and send it to a licensed wastewater treatment facility.
The larger pond holds about 330,000 gallons of water, about half the volume of an Olympic swimming pool. Six inches of soil will be removed from several heavily contaminated areas, including land between the compost building and the larger pond.
Casella will continue to take samples at the facility annually for the next 29 years. It also will monitor water quality for three years in the spring, summer and fall. The total cost of the cleaning and sampling is estimated at just over $1 million, to be paid by Casella.
The company has been conducting some cleanup operations since it filed a preliminary closure proposal to the DEP in late August. That proposal included no longer accepting sludge for processing as of Sept. 1 and removing the primary processing materials and waste by Dec. 31.
The state said Casella met that deadline. It has composted the remaining materials that make up its product and stored them at Hawk Ridge, DEP spokesperson David Madore said.
Hawk Ridge for decades had been accepting sludge from Maine, Massachusetts and other locations and processing it into compost. Some of the compost was sold in Maine until 2022, when the state became the first in the nation to ban the spread of sludge and sludge-derived compost on land. Other states are following, with 14 bills introduced as of last year, according to SaferStates.
The closure plan does not specify where Hawk Ridge might sell its remaining compost. Massachusetts had been providing 95 percent of the sludge to Hawk Ridge and using 64 percent of the compost made there, according to a 2025 report by the Massachusetts Department of Environmental Protection. Hawk Ridge is approved to use, sell sludge in Massachusetts until 2028, a MassDEP spokesperson said.
The Maine DEP licensed Hawk Ridge in 1989 to turn sludge waste into compost. Bill Ginn, a career conservationist who established the compost facility, initially recycled wood ash from paper plants and distributed it free to local farmers for fertilizer. He sold the operation three years after he started it. Three large waste companies, most recently Casella, have owned it and expanded it rapidly to take in municipal and industrial waste to turn into compost, mostly for commercial buyers.
Orlando said the gap in the current rule opens the door for Maine regulators to assure that companies operating and profiting from sludge-based composting take responsibility for the contamination they leave behind.
“It also presents an opportunity for Maine agencies and legislators to establish a closure framework that reflects current science,” she said.
Lori Valigra reports on the environment for the BDN’s Maine Focus investigative team. Reach her at lvaligra@bangordailynews.com. Support for this reporting is provided by the Unity Foundation, a fund at the Maine Community Foundation and donations by BDN readers.