"We always wait until there's a big accident to change things," he said. "Well, today we've had a big accident, it's one of the biggest ever in Canada."
The area remained part of a criminal probe and investigators were exploring all options, including the possibility that someone intentionally tampered with the train, said Quebec provincial police Sgt. Benoit Richard.
Canadian Transport Minister Denis Lebel said the train was inspected the day before the accident in Montreal and no deficiencies were found. Lebel defended his government against criticism it had cut back on rail safety measures. He said the rails remain a safe way to transport goods the vast majority of the time.
The train's owners, Montreal, Maine & Atlantic Railway, said they believed brake failure was to blame.
Local fire chief Denis Lauzon said firefighters in the nearby town of Nantes, uphill from Lac-Megantic, were called to handle a locomotive blaze on the same train a few hours before the derailment.
Joe McGonigle, Montreal, Maine & Atlantic Railway's vice president of marketing, said the fire was reported after the first engineer secured the train and went to a local hotel.
"We know that one of our employees from our engineering department showed up at the same time to assist the fire department. Exactly what they did is being investigated so the engineer wasn't the last man to touch that train, we know that, but we're not sure what happened," McGonigle said.
Nantes Fire Chief Patrick Lambert said that when his crew intervened, the engine was shut off per the standard operating procedure dictated by Montreal, Maine & Atlantic Railway. The blaze was extinguished within about 45 minutes. And that's where the fire department's involvement ended, Lambert said.
"The people from MMA told us, 'That's great — the train is secure, there's no more fire, there's nothing anymore, there's no more danger,'" Lambert told reporters. "We were given our leave, and we left."