HARTLAND — A fire Thursday evening at the Hartland Landfill remained under investigation Monday, a town official said.

A resident sent Hartland Town Manager Christopher Littlefield a picture of smoke at the landfill at around 8:30 p.m. Thursday, Littlefield said in a statement Friday afternoon.

After 911 was called, the Hartland Volunteer Fire Department responded, along with firefighters from St. Albans and Canaan, Littlefield said. Firefighters were on scene until around 12:20 a.m.

Photos posted to social media showed large flames in a relatively small area of the landfill and smoke filling the air.

No injuries were reported.

“The Town of Hartland thanks all the volunteer firefighters, support emergency personnel, and the two public works crew members who came to assist with machinery,” Littlefield said in the statement Friday.

Staff from the Maine Department of Environmental Protection, which regulates landfills, inspected the site Friday to ensure that landfill containment systems were not affected by the surface-level fire, said David Madore, deputy commissioner of the DEP.

The fire was still under investigation as of Monday afternoon, according to Littlefield. Town officials and the Fire Department are gathering information about the fire and plan to release a report in the future, Littlefield said in an email.

The DEP is expecting the report from the town once it is completed, according to Madore.

Madore said a lithium-ion battery may have caused the fire. An increasing number of fires in Maine and across the country have been attributed to such batteries, leading to questions about their safety.

“The Town is surmising that the fire was caused by a lithium-ion battery that was inadvertently disposed of in a load of construction and demolition debris,” Madore said in an email Monday.

The landfill, owned and operated by the town, is just south of Route 43/151, near the center of Hartland. It accepts several kinds of waste, including sludge, from across the state.