At least eight times in the last month, Matt Allen has had the same nightmare. He’s walking with his realty business partner through a house they’re showing when the structure begins to shake. The walls crumble and windows shatter.

But his partner just stands there, unfazed. Allen races out, barely escaping the building’s collapse, and pleads to neighbors that they’re at risk, crying, “You have to believe me, the buildings could collapse! We have to run!” But they can’t understand him.

Then, as he turns to sprint, he lurches up from his pillow, drenched in a cold sweat.

This is the new normal for the 33-year-old, since the South Philadelphia home three doors down from his suddenly exploded, igniting a massive fire on the 1400 block of South Eighth Street that left five rowhouses destroyed, 60 people evacuated, and two dead.

On Thursday, city officials announced the explosion was caused by a leak sprung by a crack in a 92-year-old natural gas main, but what caused the break remains unknown. State regulators with the Public Utility Commission have embarked on a months-long investigation to determine whether there were any violations of state or federal pipeline safety regulations.

But the city’s explanation came far too late for a slice of South Philadelphia where residents have struggled to return to their normal lives next door to what was an apocalyptic scene. Since that frigid morning on Dec. 19 when residents thanked firefighters for diving into flames, they’ve been grasping for details from city officials who knew of the cracked gas main four days after the incident but didn’t tell the public until this week, via a news conference.

The lack of transparency over the last month about what happened, who was responsible, and whether there was a continued safety threat exacerbated anxiety and engendered traumatic effects, neighbors said.

Allen and his girlfriend have spent their days hugging neighbors afraid their home could be next. Eduardo Centeno, the manager of a grocery store across the street from the explosion, has paced the aisles for weeks, compulsively checking for sounds or smells that are out of the ordinary.

Up the street, Epifania Hernández’s young grandsons have repeatedly asked her: “¿Será que va a hacer boom aquí?” — “Are we going to go boom here?”

“We’re not hearing from [the city] proactively, which I think is leading to a lot of distrust and fear,” said Leigh Goldenberg, 38, who lives around the corner from where the explosion took place and is the Democratic committee person in the area. “People feel very uncomfortable in their homes.”

That the old, busted main was cast iron, no longer standard material because it grows brittle with age, has only made the uneasiness worse. About half of Philadelphia Gas Works’ 3,000 miles of gas mains are cast-iron.

Managing director Brian Abernathy, confronted at a Thursday news conference by frustrated neighbors who asked why no one from the city had provided information earlier, apologized and said officials would work to be more transparent moving forward.

“At the very least,” he said, "we have to let them know what’s going on.”

» READ MORE: What to know about Philly’s old, brittle gas mains after a crack caused a deadly explosion

Until Thursday, city officials declined to comment on the source of the explosion, save for Fire Commissioner Adam Thiel saying in the immediate aftermath that it appeared to be “gas-fed.” At that time, witnesses also described a strong odor of gas.

Killed were Brian Diu, 28, who lived in one of the homes leveled by the blast, and Rudy Kambong, 65, who was bedridden and lived in a home adjacent to the rowhouses that collapsed entirely. Kambong’s family hasn’t responded to interview requests since his death; Diu’s family is speaking through personal-injury attorney Steven G. Wigrizer, who served as cocounsel in the trial related to the 2013 Market Street building collapse that killed seven.

» READ MORE: He wore a Phillies cap and V-necks. The South Philly explosion destroyed all physical mementos of him.

Wigrizer said Thursday that Public Utility Commission investigators — who released a preliminary report but said a full probe could take a year — need to move swiftly because “the family wants to understand why their 28-year-old son is dead.”

“If nothing caused it, and it just happened,” he said, "then that means that we’re all at risk. It’s a frightening prospect.”

A temporary gas main has been installed to service the homes on the block, and officials plan to put in a permanent main in spring or summer.

“If nothing caused it, and it just happened, then that means that we’re all at risk. It’s a frightening prospect.”

Without information on a cause, neighbors talked with one another, some sharing their own theories about what led to the explosion and piecing together memories of crews digging up the street in recent months.

A week after the blast, officials confirmed that both city workers and independent contractors dug up and then backfilled the street in October and November, largely due to defective pipes that caused a cave-in. Also, a new water service line was completed Dec. 6.

Neighbors’ fears were compounded after the explosion when Thiel said a sinkhole was forming under the street. Meanwhile, water wasn’t fully restored until earlier this month, after the block’s 160-year-old water main broke multiple times after the explosion.

“Every morning we wake up and say: ‘Is that a gas leak smell? Oh, I can’t wash my clothes,’” resident Domenica Federico said Thursday. “I pay taxes here. I’m a homeowner. I don’t see anyone knocking on my door now.”

To this day, part of Eighth Street in front of where the explosion took place still appears to be sinking, and holes that had been filled over the past few months were cracked and surrounded by traffic cones. It’s a source of constant worry for residents like Ivon Centeno Estrada, who owns the Cuernavaca Grocery at Eighth and Wilder Streets and lives in the building. She said, in her native Spanish, that the appearance of a sinkhole keeps her up at night, and a lack of information doesn’t help.

“I feel like we’ve been abandoned to our luck,” she said.

A city spokesperson said the Streets Department has been working to remove broken pavement and backfilling the street. Further Water Department work is scheduled to start Jan. 21 and will take about a week. Once that’s finished, the street can be repaved.

Allen bought the redbrick home on Wilder Street — which intersects with the middle of the 1400 block of South Eighth Street — with his girlfriend, Kara Gaulrapp, in July 2018. Allen, a software developer and part-time real estate agent, was working in his upstairs office when the December explosion rocked his neighborhood, blowing open the windows of his office and a portion of his front door.

Allen has experienced what he says are the symptoms of post-traumatic stress ever since. He’s overcome with survivor’s guilt, reliving the sight of people running toward a man’s body under debris. Meanwhile, he’s spent the last month without information about why the houses blew up to begin with. He’s constantly wondering: Will my house explode? Is the street under me going to cave? Are we safe to be here?

To fall asleep, he takes over-the-counter sleep aids and sometimes drinks alcohol. It only helps sometimes. He said he plans to seek professional help.

"I don’t need no money. I just need someone to tell me what’s going on and if it’s safe to be in my home.”

“I don’t need no money,” Allen said. “I just need someone to tell me what’s going on and if it’s safe to be in my home.”

Then, on Jan. 2, Allen went into his basement and was overwhelmed by the smell of gas. He called PGW and they arrived within 30 minutes, he said, and found a gas leak between one of the pipes that connects to the utility meter. It was fixed, but Allen still asks himself: “What if I hadn’t gone downstairs?”

Allen and Gaulrapp were not alone. PGW spokesperson Melanie McCottry said since the Dec. 19 incident, the authority has responded to 10 calls from residents within a two-block radius reporting a gas odor. Crews detected gas six times; five were due to homeowner-equipment issues. One of the readings, though, the day after the explosion, necessitated repairs to a PGW main also on the 1400 block of South Eighth Street. McCottry said the repairs were made the same day.

Gaulrapp, 29, said besides PGW coming to their home after they reported the gas odor, city officials have been “completely unresponsive." She said it was never made clear to neighbors who their point of contact in the city was or where they could direct questions about trash pickup, air quality, or services for those experiencing trauma.

“The way that it comes off to me,” Gaulrapp said, “is that the city is more concerned with bad PR than they are about the safety of their citizens and the people who live in that area.”

Hernández, 59, lives about a block from the explosion and said she’s spent most of the month “con el Jesús en la boca” — “with Jesus in the tip of the tongue,” immersed in prayer. She said it’s the uncertainty that’s been most difficult.

Several people who live in the vicinity of the collapsed homes said the only officials they heard from were volunteers with the Passyunk Square Civic Association, which left letters at homes with some information about city services. Sarah Anton, president of the association, said the group hopes to coordinate meetings between city officials and residents interested in behavioral health services.

But they needed reassurance weeks ago, she said.

City Councilmember Mark Squilla, whose district includes the block, said while the emergency response was textbook, "we sat on our laurels and have not communicated enough or better with the neighbors to make sure they know exactly what is going on.”

Abernathy, the city managing director, on Thursday took responsibility for communication that wasn’t “strong enough” and said he’d assigned a point person to provide information about cleanup efforts and the investigation moving forward.

Residents on this street just a few blocks from East Passyunk Avenue are both young professionals and retirees, recent immigrants and families who have owned homes in South Philadelphia for generations. In 2017, the area surrounding it was about 65% white and had large Hispanic and Asian populations, census data show, and more than a third of the community reported speaking a language other than English at home.

The language barrier was one of the reasons some residents felt in the dark. They worried they were missing out on communications.

Asked if information was provided to residents in languages other than English, Thiel said translators were on scene the day of and the day after the explosion, but following that, “we don’t necessarily have the on-demand capability to translate into the 140-ish different languages that are spoken in the city of Philadelphia."

For Centeno Estrada, the grocery store owner, it’s the financial impacts that have been most stark. The family-run store’s windows blew out, and the shop — where customers buy fresh produce and send remittances to relatives in Mexico or Central America — was closed for two weeks. Centeno Estrada, 40, said they lost an estimated $8,500 in merchandise that fell off the shelves, went bad because the electricity was turned off, or was broken by a car bumper that flew into the store as a result of the blast.

Two broken windows and a shattered door that won’t close remain to this day. They’re covered with tape and torn plastic bags. Centeno Estrada said her insurance policy doesn’t cover the damage, and she’s worried how she’ll recoup the losses.

“Nobody is supporting me,” she said.

» READ MORE: Dramatic video shows firefighters diving into South Philly blaze moments after explosion

Across the street, Francis and Ditta Hoeber, 77, own the tall brick building that has both commercial and residential space next to the rowhouses that crumbled. Commercial insurance is covering some of the thousands of dollars in damage, including from smoke and water, that the building sustained. But there are still constant reminders of the tragedy that happened here.

“The experience as a whole doesn’t go away,” Francis said. “Money doesn’t cover that.”

Ditta said among the most harrowing experiences was reentering her home after they’d been evacuated. Broken glass was on the floor, the hallways smelled of smoke, dust had rendered the floor gritty.

And the stairways had black marks that appeared to be from the firefighters, Francis said — the ones who brushed up against the walls in a rush to stand on the roof, where they battled the flames shooting upward from what used to be the homes next door.

Staff writers Claudia Vargas and Oona Goodin-Smith contributed to this article.