Baltimore County

No one injured in explosion and two-alarm fire at a building at Back River Wastewater Treatment Plant

Firefighters are on the scene of an explosion and fire in a sludge handling building at the Back River Wasterwater Treatment Plant.

An explosion and two-alarm fire badly damaged a building Wednesday morning on the Back River Wastewater Treatment Plant campus in Dundalk, officials say.

Seven people were working in the building at about 11:30 a.m. when the explosion occurred, but no one was injured, said Elise Armacost, spokeswoman for the Baltimore County Fire Department.


The building, operated by a private contractor named Synagro, dries out solid waste from the treatment plant into pellets that can be used as agricultural fertilizer, Armacost said.

Firefighters battled multiple fires in the building, Armacost said. At one point, the commander on the scene evacuated his crew because of damage to the building’s structural integrity.


“There is still fire in that building,” Armacost said during a news conference just after 2 p.m. “Having reassessed the building, our crews are preparing to go back inside — if they haven’t already — to deal with the fire, prevent its extension and get that completely out. That is likely to take a while. So I think it’s safe to say our fire department will be maintaining a presence here for much of the day.”

The fire was placed under control at about 3 p.m., Armacost said later.

The fire department was particularly wary of about 12,000 gallons of thermal oil in the building, Armacost said. Most of the oil is in tanks, she said, but the remainder is being allowed to burn off. Thermal oil does not warrant a hazmat response, Armacost said. The Maryland Department of the Environment was on site Wednesday.

The Baltimore City Police Department and Baltimore City Fire Investigations Division will be investigating the cause of the blaze at the plant, which is located in Baltimore County but owned and operated by the Baltimore City Department of Public Works.

Over the past few years, the plant has made headlines for pollution overages into the Back River caused by maintenance issues and inadequate staffing. The problems infuriated neighbors living along the water in Essex after they were warned last summer to avoid contact with the water near the plant due to high bacteria levels.

The state of Maryland sued Baltimore last year over the pollution problems at the plant and at the city’s other wastewater treatment plant on the Patapsco River, which also has released large amounts of inadequately treated sewage. Officials have said they are negotiating a consent decree that would require improvements at both plants.

In recent months, Back River has come into compliance with its pollution limits, though internal problems with the facility’s machinery have persisted. Staffers from the Maryland Environmental Service, who were dispatched to the facility last year amid the pollution problems, remain to help with construction projects.

During the news conference Wednesday, Blair Adams, a spokeswoman for the Baltimore City Department of Public Works, said the Back River facility continues to treat waste “business as usual.”


Still, Synagro’s pelletizing is an important step in the whole operation, because it allows the solid waste residuals to be moved off-site as fertilizer. According to a June 2022 report by the Maryland Environmental Service, Synagro handles 70% of Back River’s solid waste output.

Layne Baroldi, Synagro’s vice president of government affairs, said in an interview that his company is likely to bring in portable equipment to continue producing pellets for now. He said the company is still investigating the cause of the explosion.

“Right now, we’re pretty much waiting to get back in to assess the damage, but in the meantime were putting together plans for alternative processing,” Baroldi said.

Elise Armacost (right) and Blair Adams at presser outside waste treatment facility.

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According to the MES report, Synagro’s pelletizing process at Back River was not in operation from November 2021 to March 2022. That’s because the building’s fire suppression system relied on clean water flowing from the plant. That water contained too many solid waste particles, so it began clogging Synagro’s equipment, according to MES.

With the pellet facility offline, even more solid waste began to pile up in key parts of the wastewater treatment process at Back River.

“This had a significant adverse effect on the ability of the facility to meet its discharge permit,” reads the MES report, referencing the permit that regulates the quantities of nutrients and bacteria it can release into the river.


The 2022 MES report faulted the leadership of the city Department of Public Works for a lack of urgency when it came to bringing clean water into the pelletizer building so it could resume functioning.

In a statement Wednesday, nonprofits Blue Water Baltimore and Chesapeake Legal Alliance, which have active litigation against Baltimore seeking to improve the wastewater treatment plants, said the explosion “underscores the importance of developing and implementing a comprehensive plan quickly, including third party oversight” for the plants.

The Maryland General Assembly is currently considering a bill that would convene a task force to look at alternative governance for Baltimore’s drinking water and wastewater infrastructure, most of which is run by the city though it serves the much larger metro area. Some environmental groups have expressed concern about who would be allowed to sit on the task force, which could start the process toward a regional water authority in the Baltimore area.

Baltimore Sun reporter Dillon Mullan contributed to this article.