Priscilla Liguori, WFMZ 69 News

POTTSTOWN, Pa. - Investigators will return to a Pottstown neighborhood on Thursday to check the safety of homes near the site of last week's deadly explosion.

A U.S. senator, a congresswoman and home inspectors were among those who joined investigators Wednesday at the scene of the explosion.

Last Thursday's blast killed four children and their grandmother. It left their parents hospitalized.

Now, a local official is putting at least one rumor to rest.

It's been six days since the violent explosion on Hale Street and everyone wants to know what caused it. We still don't know that answer, but Wednesday, the fire chief confirmed it was not a meth lab.

Splintered roofs, shattered windows, and broken hearts surround the scene of the Pottstown explosion.

Inspectors assessed the structural damage of neighboring homes, including that of Tandra Rambert.

"I lost everything," said Rambert. "I'm thankful that me, my son, we made it out alive."

"Our L & I (licensing and inspections) people went in to see if people had cracks in their homes," said Pottstown Fire Chief Frank Hand.

"What we determined was there's three additional properties we're going to have the structural engineer come and look at, on top of the original six," said Keith Place, the director of licensing and inspections for Pottstown.

In the meantime, displaced families, and the many mourning the four children and their grandmother killed in the blast, search for answers.

"We make sure we figure out what happened, what went wrong, so that it never happens again," said U.S. Rep. Madeleine Dean. "The sight of this blast is utterly heartbreaking."

"Without seeing it, I'm not sure you have a sense of it," said U.S. Sen. Bob Casey. "Whatever this community needs, we want to be there to support."

"It's something that should have not happened especially with the gas smells that we've been talking about for years at the end of the corner that everybody kind of dismissed. People come out, say it's okay and leave," said Rambert.

PECO has noted the homes that blew up weren't served by its natural gas, though there are natural gas mains in the area. It said Wednesday it continues to support the investigation in a variety of ways.

The company said, "To date, we have not found evidence that PECO's natural gas caused this incident. To be clear, the investigations are ongoing."

For Rambert, so is the grief for the neighbors she will never see again.

"I always think about the children that died, because I'd always see them when I drove home, playing out there with their mom in the yard," said Rambert. "People need to be held accountable for this tragedy."

The structural engineer is scheduled to look at the nine properties Thursday.

Pottstown police, ATF, and state police are all investigating.

See full article and video here.