DUNMORE — An 86-year-old Dunmore woman died instantly Thursday morning when her home exploded and collapsed following a water main break and natural gas leak on Smith Street, state police fire marshals said.

Madlyn M. Mecca, 413 Smith St., was leaving her home shortly before 4 a.m. because police and firefighters evacuated the area, due to a heavy odor of natural gas. A neighbor, whom state police did not identify, was moments away from picking up Mrs. Mecca. Mrs. Mecca waited on her front porch for her neighbor, but natural gas had seeped into her home and some ignition source had turned on, sparking a fire and an explosion, state police said. Mrs. Mecca was killed immediately.

“She was out,” said her cousin and neighbor, Carmel Verrastro Biko. “Originally, she was out ... we don’t know if she went back in the house or if she was just out there waiting for him to come.”

Video by Paul Nardozzi

The fire was ruled accidental, state police said. It’s not clear what ignited the explosion, but any number of appliances could have been the culprit. A furnace, a water heater, pilot lights or any electrical appliance turning on could have done it.

The explosion destroyed Mrs. Mecca’s home and catastrophically damaged the home next door, a three story apartment building at 411 Smith St. Only rubble remained of the home where Mrs. Mecca lived her whole life. The roof was gone on 411 Smith St. and a wall had collapsed. Ash rained down around the fire scene and coated some areas in soot. Mist from the fire hoses iced on the pavement and some firefighters slipped, though no one was seriously injured, Dunmore Fire Department Capt. Mike Rinaldi said. Many cars nearby were damaged and at least one looked like it had caught fire itself.

Mrs. Mecca’s home, where she lived alone, exploded at 3:49 a.m. Multiple alarms were called in after that, and fire companies from Scranton through the Midvalley responded.

“It was an extremely intense fire,” borough Fire Chief Chris DeNaples said.

The water main break cut service to one of the fire hydrants close to the fire, and firefighters had to briefly scramble to connect to a hydrant a little further away, Chief DeNaples said. However, it did not take long to establish a full attack on the blaze.

It’s unknown what caused the water main break and natural gas leak.

UGI Utilities got a gas odor call from 911 at 2:23 a.m., arrived at 2:50 a.m., and said the gas was off in the 300 and 400 blocks of Smith Street at 3:46 a.m., said UGI spokesman Don Brominski on the scene. Evacuations began immediately.

A UGI news release issued later Thursday said that UGI provided a formal notification of the incident to the state Public Utility Commission and added that UGI is cooperating with the PUC and the state police in the investigation. Robin Tilley, a spokesperson from the PUC, said an engineer was on scene investigating, but had no further information Thursday.

Pennsylvania American Water issued a news release that said the water utility coordinated with crews from UGI and the state police regarding repairs to a broken water main at the intersection of Smith and Laurel streets. They awaiting authorization from state police to begin repairs to the main, which gushed water along Smith Street all morning. No one was without water because of the broken main, spokesperson Susan Turcmanovich wrote in the release. About 80 people had gas service disrupted Thursday, UGI said.

The PUC and UGI will use underground cameras and will excavate water and gas pipes to determine the failure, state police said.

Gas pipelines on Smith Street between Laurel and Meade streets were last replaced last spring with new, high-density plastic lines, Mr. Brominski said.

Numerous crews bored holes into the road to investigate and vent gas that was still trapped.

Natural gas from the leak seeped into Mrs. Mecca’s home likely by following the water and sewer line that ran from the street into the home, state police said. Once an ignition source was introduced, the house exploded.

Charlie Mecca, a distant cousin of the victim who lives two homes down, said he was asleep in bed around 3:30 a.m. All of a sudden, there was an “unbelievable explosion.” It rattled his whole house. The shock wave was so powerful it shattered windows in neighboring houses, Mr. Mecca said.

“I literally thought someone had run into my house with a car,” Mr. Mecca said. “That’s how my house shook.”

His wife started screaming “get out of the house, get out of the house,” he said. They dressed quickly and ran outside. He saw the flames tower 50 feet into the air.

“It destroyed that house and the house next to it,” Mr. Mecca said. “It didn’t take more than 15 minutes for the entire thing to go.”

He knew who lived there, but word started spreading Mrs. Mecca had made it out. Mr. Mecca had heard she was at the community center, which had been set up as a temporary American Red Cross warming station. He hoped it was true.

“I was told [that],” Mr. Mecca said, long before the fire was out and details solidified. “Again, this is all second-hand information, the entire neighborhood was out in a matter of minutes.”

The fire burned for at least three hours, while firefighters poured water from the ground and from two ladder trucks extended over the destroyed structures. Eventually, the sun rose and the scope of the damage was apparent.

“I was shocked,” said Dominic Verrastro, another cousin. “There’s no house there.”

Dread settled in family members’ hearts when no one had seen Ms. Mecca at the community center.

The worst was all but confirmed around 8 a.m., when Lackawanna County Coroner Tim Rowland came out of the driver’s seat of a large black van parked at the foot of the rubble, near where the porch used to be.

Both cousins described Ms. Mecca as a loving woman who was fiercely independent and refused to grow old. Every snowstorm, she donned warm clothing, took up a shovel and dug herself out. She didn’t want help, but she never hesitated to lend her own.

“That’s just how she was,” Mr. Verrastro said. “Cooking, and any time someone needed some help on this block, she’d be the first one there.”

Mrs. Mecca’s mastery of Italian cooking earned her recognition three years ago in the Times-Tribune’s Local Flavor section. The newspaper highlighted her Fig, Date and Raisin Roll recipe. Her stromboli should be lauded too, her cousins noted.

“She was the typical little Italian grandmother that maybe everyone doesn’t have but should have,” Mr. Verrastro said.

She left behind a son and two grandchildren, her family said.

KYLE WIND, staff writer, contributed to this report.

Contact the writer: jkohut@timesshamrock.com, @jkohutTT on Twitter