BALTIMORE – A natural gas explosion destroyed three row houses in Baltimore on Monday, killing a woman and trapping other people in the wreckage. At least four people were hospitalized with serious injuries as firefighters searched for more survivors.

Dozens of firefighters converged on the piles of rubble. A fourth house in the row was ripped open, and windows were shattered in nearby homes, leaving the Reisterstown Station neighborhood in northwest Baltimore strewn with debris and glass.

"It's a disaster. It's a mess. It's unbelievable," said Diane Glover, who lives across the street. The explosion shattered her windows and blew open her front door, bending the frame. "I'm still shaken up," she said hours later.

Rescuers were painstakingly going through the wreckage by hand. About two hours after the explosion, a line of firefighters removed a person on a stretcher to a waiting ambulance.

At least five people were inside, maybe more, when the homes exploded, said Baltimore Fire Department spokeswoman Blair Adams.

"They were beneath the rubble," Adams said. "You have homes that were pretty much crumbled. ... A ton of debris on the ground. So, we're pulling and trying to comb through to see if we can find any additional occupants."

While the cause wasn't immediately clear, the Baltimore Sun reported last year that dangerous gas leaks have become much more frequent, with nearly two dozen discovered each day on average, according to Baltimore Gas and Electric's reports to federal authorities. The utility has thousands of miles of obsolete pipes that need to be replaced, an effort that would cost nearly $1 billion and take two decades, the newspaper said.

BGE turned off the gas in the immediate area after receiving an "initial call" from the Fire Department. "Once the gas is off, we can begin to safely assess the situation, including inspections of BGE equipment," said utility spokeswoman Linda Foy.

Glover, 56, and her father, Moses Glover, 77, were at home when the massive explosion shook their house. "I jumped up to see what was going on. I looked out the bathroom window and there was a house on the ground," she said. "It sounded like a bomb went off."

Neighbors scrambled toward the rubble, calling out for survivors. Kevin Matthews, who lives on the block, said that he could hear trapped children shouting: "Come get us! We're stuck!" Firefighters and police officers then arrived and took over.

In late 2017, BGE asked the Maryland Public Service Commission (PSC) to approve a new gas system infrastructure and a cost recovery mechanism to pay for upgrades.

"Founded in 1816, BGE is the oldest gas distribution company in the nation. Like many older gas systems, a larger portion of its gas main and services infrastructure consists of cast iron and bare steel — materials that are obsolete and susceptible to failure with age," the PSC wrote in a 2018 order approving a modernization plan.