Associated Press

LAWRENCE, MASS.

Investigators worked Friday to pinpoint the cause of a series of fiery natural-gas explosions that killed a teen driver in his car just hours after he got his license, injured at least 25 others and left dozens of homes in smoldering ruins.

Authorities said an estimated 8,000 people were displaced at the height of Thursday’s post-explosion chaos in three towns north of Boston rocked by the disaster. Most were still waiting, shaken and exhausted, to be allowed to return to their homes.

Gov. Charlie Baker said Friday that hundreds of gas technicians were being deployed throughout the night and into today to make sure each home is safe to enter.

Even after residents return and their electricity is restored, gas service won’t be turned on until technicians can inspect every connection in each home – a process that could take weeks.

“This remains a tremendous inconvenience for many people,” Baker said. “It’s essential for the crews to get this right.”

The National Transportation Safety Board sent a team to help investigate the blasts in a state where some of the aging gas pipeline system dates to the 1860s.

The rapid-fire series of gas explosions that one official described as “Armageddon” ignited fires in 60 to 80 homes in the working-class towns of Lawrence, Andover and North Andover, forcing entire neighborhoods to evacuate as crews scrambled to fight the flames and shut off the gas and electricity.

Gas and electricity remained shut down Friday in most of the area, and entire neighborhoods were eerily deserted.

Authorities said 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 Thursday evening.

Rondon, a musician who went by the name DJ Blaze, had just gotten his driver’s license hours earlier, grieving friends and relatives told The Boston Globe. “It’s crazy how this happened,” said a friend, Cassandra Carrion.

The state Registry of Motor Vehicles said Rondon had been issued his driver’s license only hours earlier Thursday.

The NTSB said Friday that its team should on the scene for a week. The agency said the team will be gathering perishable evidence from the accident site and pulling together information from federal, state, and local agencies, and from Columbia Gas.

The agency said among the issues to be examined are the design of the pipeline system, any upgrades and the operator’s management of the pipeline. A review of the emergency response of the operator and local first responders will also be conducted.

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 canceled Friday as families waited to return to their homes.

The governor said state and local authorities were investigating but it could take days or weeks before they turn up answers.