It took Montgomery firefighters 11 days to totally extinguish last month's fire at the county's Dickerson, Md., incinerator unit, which started when an 85-foot high mound of trash ignited. (Montgomery County fire dept.)

The December trash fire that smoldered for nearly two weeks inside Montgomery County’s waste incinerator was the latest in a series of problems that have plagued the plant, keeping it either completely or partially out of service for nearly a third of 2016, according to records and interviews.

The 20-year-old Resource Recovery Facility in rural Dickerson, Md., is operated for the county by a private company and can burn up to 689,000 tons of commercial and residential waste annually. Three industrial furnaces heat the waste and help convert it to electricity.

Records show 105 days of unscheduled outages between March and October of last year. Shutdowns last month and in July forced the county to find other destinations for about 55,000 tons of trash, officials said. The plant was fully in operation for just nine days in September and October.

For several months in 2016 the facility stored trash in excess of its 12,000-ton design limit, according to the Northeast Maryland Waste Disposal Authority. The independent state agency issues bonds to finance construction of waste disposal sites and contracts with the private operator of the facility, New Jersey-based Covanta.

At the time of the December fire, 12,900 tons were awaiting incineration.

Joey Neuhoff, regional vice president for Covanta, said the volume in excess of 12,000 tons did not violate its state permit, which covers only the amount of waste the plant can accept annually and how long it can be stored before processing.

But Neuhoff said “no one at the company is pleased” about the situation. He attributed the problems to an unusually high volume of waste and a shortage of key spare parts.

“When a plant reaches middle age, parts start to fail, and you need to keep critical spares available,” Neuhoff said. “We didn’t have a good critical spare inventory.”

Although no official cause for the December fire has been identified, Neuhoff said the plant’s operational difficulties were not a factor. Firefighters responded to smaller blazes at the facility in July and October.

County Council president Roger Berliner (D-Potomac-Bethesda) has scheduled a Feb. 2 hearing on the fire and the plant’s operations. In an interview, he expressed skepticism about the idea that the fire and operational problems were unrelated.

“It has a smell to it,” said Berliner, who chairs the council’s transportation and environment committee. The hearing will be before that committee and the council’s public safety committee.

Fire and Rescue Chief Scott Goldstein says there are three possible ways a fire can erupt when dealing with mass amounts of solid waste: ignition of fireplace ashes or other “hot trash,” sparks from a decaying battery, or spontaneous combustion of organic material.

Montgomery’s Department of Environmental Protection is conducting an investigation of the plant’s problems and expects to have a report ready for the hearing, director Lisa Feldt said.

Tim Firestine, the county’s chief administrative officer, suggested in an interview that it may be time for Montgomery to step in and oversee incinerator operations.

Although not directly criticizing the state waste disposal authority, Firestine said: “We have to look at how we unwind that. Maybe we need a direct relationship.”

The Dec. 8 fire involved a tower of trash eight stories high and 200 feet wide. It filled the 30-foot-deep storage pit where waste awaits incineration and extended another 55 feet into the air.

Smoke from the blaze prompted the county to warn residents living within a mile of the plant to stay indoors or leave the area if they had asthma or other lung or heart issues.

Feldt said the Maryland Department of Environment is testing air and water samples from the fire for toxins. The water firefighters used to quell the blaze was routed to a storage pond until tests show if pre-treatment is needed before it is discharged into the Potomac River.

Fire personnel spent 11 days extinguishing the fire. After it was put out, Local 1664 of the International Association of Firefighters filed a complaint with Maryland Occupational Safety and Health, charging that the county did not make an adequate evaluation of the hazards at the site and left firefighters without proper protective gear as they worked.

Jeff Buddle, local president, said a half-dozen first responders had to seek medical treatment. One has lost time from work because of illness. “We definitely think it was directly related to the incident,” Buddle said.

The state agency has started an investigation, but a spokeswoman said she could not comment on an active case.

Goldstein said the fire department “took care of providing the right equipment and adequate information about decontamination.”

The plant was approved by the council in 1987, after 15 years of debate over the county’s mounting trash problems.

It opened in 1996, following rounds of litigation brought by neighbors who objected to the addition of an incinerator to a community that was already home to a power plant — currently owned by NRG Energy — and the county’s leaf-composting operation.

Jane Hunter, who can see the waste plant’s 275-foot smoke stack about two miles from her front door, said that when the wind blows in a certain direction, she smells the garbage. Beeping and other noise from trucks offloading trash is frequent.

The fire “should never have happened,” said Hunter, 74, who still grows corn soybeans and wheat on about 1,000 acres. “It’s absolutely inexcusable.”