The natural gas company has a plan to return service to the nearly 8,000 homes and businesses without heat and hot water, but it will take months and require digging up miles of streets. Meanwhile, displaced residents calculate their losses and look for Columbia Gas to make the region whole again.

Residents face the first day of life after what’s now known as the Merrimack Valley Disaster. Uncertain when they will be able to return to their homes, they start to pull together, assess the damage and ask what happened. They are told that a distribution pipe was over-pressurized, which raises the questions: Could that

When WGBH reporters start making their way to the Merrimack Valley, all they know is that buildings and homes are blowing up and catching fire. When they arrive, they discover smoke-filled streets, frightened residents and entire communities wondering if this is over, and what comes next? Soon, one thing is clear: It’s not safe to go back home tonight, and no one knows when it will be.

Within moments of the first alarms, homes and businesses in Massachusetts’ Merrimack Valley are aflame. Hundreds of people call 9-1-1, as thousands of residents in Lawrence, Andover and North Andover run from their homes, seeking safety in the streets. By the time the gas is shut off, 131 buildings are damaged or destroyed, one person is dead, and nearly two dozen are transported to hospitals.

On Sept. 13, 2018, at 4:04 p.m., an alarm sounded at a natural gas monitoring center in Columbus, Ohio. High-pressured natural gas had just been released into a low-pressure gas line in Massachusetts’ Merrimack Valley. Soon,buildings in Lawrence, Andover and North Andover would explode and catch fire. Thousands of people would be ordered to flee their homes and seek safety on the streets. WGBH Reporters were there to collect their stories and get answers to the questions on everyone’s mind: How did this happen? And, could it happen again?