Cables carrying electricity and information — the hidden lifeblood of Baltimore — thread through hundreds of miles of terracotta tubes so old that PVC pipes hadn’t been invented when they were buried below the city streets.

Those clay conduits keep catching fire, sometimes exploding and turning 323-pound manhole covers into dangerous projectiles.

There’s no consensus as to why. And there’s no clear answer as to whose responsibility it is to prevent it from happening again.

A variety of underground stakeholders operate in and around the city-owned conduit, leaving each one pointing fingers and looking at others for answers. The City Council has scheduled a hearing Tuesday, its second on the issue in a year.

“Everybody is cagey because no one wants to take responsibility,” said Councilman Mark Conway, who called for the hearing. “There’s a lot of infrastructure down there. ... There’s so many things that could go wrong.”

These kinds of fires have been occurring for a century. But the pace is picking up, and the concentration is noticeable:

Eight times in roughly two years, underground forces like fires have blown off manhole covers. Three of those incidents occurred in a small slice of downtown Baltimore, including the most recent one, on June 28.

A 2023 agreement between the city and the region’s utility and primary conduit user, Baltimore Gas and Electric, has muddled the issue of responsibility.

One especially explosive inferno in September on Charles Street swallowed up a bookstore, caused over $300,000 in damage and left 2,000 people without power, according to a report BGE filed to state regulators.

That fire prompted four separate studies. Still, eight months later, it is uncertain what caused it. BGE has a theory — but hastens to add that it doesn’t believe it should be the primary investigator.

Months after the September blast, Mayor Brandon Scott’s office sought a third-party investigator to help. As they searched, another explosion occurred, and the city hired RTI Consulting as the investigator of both of those blazes.

Both Baltimore and BGE, which occupies 75% of the conduit, generally blame the fires on brittle infrastructure dating to the 19th century, which would require an extraordinary investment to entirely replace. But age alone doesn’t explain a surprising string of fires, experts say.

Environmental factors can alter subterranean conditions. And Baltimore’s underground is crowded with pipes full of steam, natural gas or water, which could pose problems for the adjacent conduit. Within it, older cables are often encased with a plastic coating that can decompose, producing flammable gases and exposed wires.

It’s an underworld that operates unseen — until it erupts.

Competing theories

The city has always owned the conduit, and it charges tenants, including BGE and Comcast, to use it. That makes Baltimore atypical. In other cities, including Philadelphia and New York, a utility owns the system.

BGE unsuccessfully sought to purchase Baltimore’s conduit for $100 million in 2015, a move that would have allowed the company to charge other users for access.

Bernard C. “Jack” Young, then the City Council president, felt that BGE low-balled the city, and was never a fan of selling the conduit, anyway. He later helped usher in a charter amendment, approved in 2022, that permanently prohibited its sale.

Months later, Scott’s office and BGE reached an agreement on a controversial new deal that wasn’t a sale, but still yielded some power and responsibility to the utility.

The city remained on the hook for the conduit’s maintenance, but BGE largely took over capital improvements, allowing it to determine how revenue generated by the conduit was spent to improve the infrastructure.

Since the agreement was signed, Baltimore’s Conduit Division has been slashed from 100 employees in 2022 to 58 today, although city transportation officials argue that the cuts have not affected conduit maintenance.

The city does not perform routine conduit inspections, rather only upon request. Asked about the notorious area around Charles Street downtown, the city said it has conducted roughly 160 inspections there in the past two years.

Jonas Poggi, a spokesperson for Scott, said in a statement that the city has a “significant responsibility” to ensure the conduit’s safety, but added that there are “numerous users of the conduit who are responsible for their utilities underground.”

BGE spokesperson Nick Alexopulos said in a statement that BGE has found its equipment to be “in good working condition,” emphasizing that other utilities, like water and steam, are nearby.

Vicinity Energy, the steam line’s owner, did not respond to requests for comment.

Alexopulos also played down BGE’s role in capital improvements. The city is “ultimately responsible for the condition of the system,” he said, adding that Baltimore is free to to make capital improvements, too.

Comcast spokesperson Kristie Fox said the company will “continue to support BGE and the City’s efforts to identify the root cause of the recent fires.” Another telecom company that uses the conduit, Crown Castle, did not reply to requests for comment.

The city’s continued ownership of the conduit was a crucial aspect of BGE’s analysis into September’s fire. BGE said the city — which “owns, maintains and manages the conduit system” — is solely responsible for investigating the incident. As a tenant, BGE said, it would not lead a formal investigation.

That didn’t stop the company from forming a supposition: The city’s trenching work to replace water lines the year prior “likely caused the conduit to collapse,” leading to damaged cable insulation and, eventually, the fire.

The Scott administration disputes BGE’s findings. His office said a city investigation found that the city’s “construction activity did not contribute to the fire.”

The cause of the most recent fire is still under investigation, but BGE “strongly suspects” that other underground facilities “may have been a causative factor,” Alexopulos said.

BGE also said that a January 2024 fire on Charles Street “may” have been due to a damaged section of conduit, and indicated that it could do a better job than the city of caring for the buried infrastructure. These incidents “simply do not occur” in areas where “BGE owns and maintains the conduit system,” the company said.

Underground fires and manhole explosions happen in other large cities, too, including Washington, Philadelphia and New York City. But they became enough of a problem locally that, in 2023, the Maryland Public Service Commission required utilities to list them in annual reports.

Commission reports show that eight times since January 2023, Baltimore’s manhole covers have been lifted, either by by blazes or other underground pressure. The state has only seen one such instance elsewhere, in Harford County in 2024.

City officials said there have been about 15 underground fires in that time.

After Baltimore’s headline-making Charles Street fire last year, Scott announced he would convene a workgroup including conduit stakeholders. They met once in October, Scott’s office said, but not again since.

Missed by millimeters

Two weeks after the most recent underground fire, a block from City Hall, the area still resembled an active construction site.

A BGE worker submerged in a manhole navigated a hefty spaghetti of cables as crews continued repair work on the 300 block of Baltimore Street. Three lanes of traffic gridlocked into one.

Elisa Milan, owner of The Empanada Lady, surveyed the hard hats and utility trucks as she considered lost revenues due to decreased foot traffic. The fire caused the Puerto Rican restaurant to lose internet access for 12 days, complicating business. Employees could not access the cash drawer and had to track employee hours and tips manually, Milan said. Even basic functions, like playing music, were a challenge.

Service was restored after Milan filed a complaint against Comcast with the Federal Communications Commission, she said. Comcast said the delay in service restoration was due to inability to access nearby manholes following the fire.

When the conduit caught fire, staff and customers were warned by authorities to remain inside. The underground blazes can build up energy and launch manhole covers into the air, like missiles, with the force of a dozen sticks of dynamite.

Milan said she is “absolutely concerned” about the consequences of another incident.

“We walk on manholes every day,” she said.

When a manhole cover shattered Gian Marco Menswear’s windows on Charles Street a few years ago, owner Marc Sklar said it missed an employee “by millimeters.”

A popular Irish pub, Mick O’Shea’s, closed for weeks after September’s explosion. A handwritten note on its door explained that its closure was “due to the fact that the powers that be failed to maintain the infrastructure.”

The stage for such disasters was set in the 1890s.

Overhead telegraph and telephone wires congested city streets, so Baltimore officials decided to bury them within a “subway for wires,” as Baltimore Sun articles described it at the time. (Thankfully, the city opted for terracotta instead of treated wood, which was also considered as a cheaper option.)

The 741-mile conduit system, accessed via 12,000 manholes, can range from two feet deep to 20 feet deep. The ducts that carry cables in the conduit can barely fit a softball.

The system is today made of about 80% terracotta or orangeburg, another outdated piping, encased in concrete. The rest has been Band-Aided over the years and modernized using PVC pipe.

“A lot of it is not in good shape,” said Ernest George, who retired as a city conduit inspection supervisor last year.

On a recent walk downtown, George recounted his 38 years with the Conduit Division. He once narrowly avoided injury when a manhole exploded near him.

He’s seen firsthand just how crowded Baltimore’s basement is. “Something’s gonna give,” George said.

Asked who can prevent future underground explosions, he thought of a higher power.

“God, that’s who has control,” he said.

‘A lot of things all around, entangled’

After the September fire, Scott was asked if he could confidently say that the Charles Street area was safe. Shying away from predictions, Scott said that although he is the mayor, he is not the omniscient “Great Wizard of Oz.”

“I can’t say that another fire isn’t going to happen,” he said.

Another downtown explosion came. And more are likely to follow.

Baltimore’s underground is especially busy downtown, where there is a concentration of buildings.

“In a big, heavily dense city, you do have a lot of things all around, entangled, and interconnected physically with electrical,” said Rae Zimmerman, a New York University professor who studies underground infrastructure resilience.

External factors, like water and salt, can damage underground infrastructure. Moisture can creep into conduits and cause deterioration of the plastic coating of old cables. That decomposition can create a “smoldering” fire event, said Bill Koffel, a University of Maryland professor of fire protection engineering.

Steam — much of which comes from the trash incinerator — heats many buildings downtown, as evidenced by clouds of it that noticeably escape from the ground. It generates heat and moisture, which can cause conduit problems, Koffel said.

Natural gas and steam could be contributing factors to fires that cause manhole cover explosions, said Chuck Hookham, an engineering consultant.

“That’s where I would look first,” he said.

BGE has said it has “no records indicating natural gas” was present at recent manhole fires.

As if there’s not enough going on underground, conduit pirates also strike.

In some cases, unauthorized users prop open manhole covers to access the conduit without paying, city transportation officials said. (The city considered placing locks on covers in 2017, but decided that would complicate 24-hour access.)

Illicit access can cause overcrowding. Zimmerman stressed the importance of tracking inventory — knowing exactly what is in every inch underground.

Like it or not, underground fires are a Baltimore staple, predating, even, Old Bay spice.

The very first one on record?

In 1922, a manhole cover blew, nearly injuring several Goucher College students on, you guessed it, Charles Street.

Baltimore Banner reporter Tim Prudente contributed to this article.