The Department of Environmental Protection says the moving of dirt and trash to stop the fire at the Juniper Ridge landfill in Old Town will likely prevent it from determining a cause.
DEP Deputy Commissioner David Madore said the fire might have damaged some gas infrastructure at the landfill, which is being evaluated.
But the department is not monitoring the air quality around the site after the Monday fire, which burned for four hours before being contained. He said no more emissions are coming from the site since the fire was put out.
Madore also said responders prevented any water runoff used to fight the fire from entering local rivers. He said DEP staff will return to the site on Thursday.
Environmental activists have criticized Casella Waste Systems' management of the site and how it handles toxic sludge in recent years. Its proposed expansion and acceptance of out-of-state trash has also faced criticism from locals who worry about the landfill's environmental impact on their area.
Don't Waste ME's Ed Spencer, who lives in West Old Town, said both the state and Casella need to be more forthcoming about how such incidents happen and when they happen.
"We want to know what happened and... exactly what is going on in as real time as possible," he said.
Penobscot Nation Chief Kirk Francis said he is still looking for answers after tribal members complained about burning eyes and sore throats in the wake of the fire. He said it's an especially pressing issue as the region is right in the middle of the fiddlehead harvesting season.
"So yeah, we had, we had a lot of concerns, and we still do," he said.
Francis says he is working with the tribe's local U.S. Environmental Protection Agency trustee to get information about the fire.
The tribe has raised concerns about the landfill's close proximity to the Penobscot River for years. Its Indian Island reservation is about four miles away.