Investigators are working to pinpoint the cause of a series of dramatic natural gas explosions that killed a teenager, injured at least 25 others and left dozens of homes in smouldering ruins north of Boston.
An estimated 8000 people were displaced at the height of Thursday's post-explosion chaos in three towns north of Boston that were rocked by the disaster.
The National Transportation Safety Board sent a team to help investigate, saying pipelines are within its jurisdiction.
The rapid-fire series of gas explosions that one official described as "Armageddon" ignited fires in 60 to 80 homes in Lawrence, Andover and North Andover, forcing entire neighbourhoods to evacuate as crews scrambled to fight the flames and shut off the gas and electricity.
Gas remained shut off on Friday in most of the area, and the streets were eerily deserted.
Leonel Rondon, 18, of Lawrence, died after a chimney toppled by an exploding house crashed into his car.
He was rushed to a Boston hospital and pronounced dead there on Thursday evening.
Massachusetts State Police urged all residents with homes serviced by Columbia Gas in the three communities to evacuate, snarling traffic and causing widespread confusion as residents and local officials struggled to understand what was happening.
Some 400 people spent the night in shelters, and school was cancelled on Friday as families waited to return to their homes.
Governor Charlie Baker said state and local authorities were investigating but it could take days or weeks before they turn up answers, acknowledging the "massive inconvenience" for those displaced.
He said hundreds of gas technicians were going house to house to ensure each was safe.
The three communities house more than 146,000 residents about 40km north of Boston, near the New Hampshire border.
Andover Fire Chief Michael Mansfield described the blasts.
"It looked like Armageddon, it really did," he told reporters.
"There were billows of smoke coming from Lawrence behind me. I could see pillars of smoke in front of me from the town of Andover."
The Massachusetts Emergency Management Agency blamed the fires on gas lines that had become over-pressurised but said investigators were still examining what happened.
Australian Associated Press