Jurors in eastern Canada on Friday found three men not guilty of criminal negligence following an oil train disaster that left 47 people dead. The accident in July 2013 involved a U.S.-owned train carrying North Dakota crude oil. In the aftermath, regulators in the U.S. and Canada adopted sweeping reforms to the way railroads haul and manage hazardous cargoes.

The accident occurred on a summer evening after a rail worker left an industrial train unattended on a hillside above the village of Lac Megantic, Quebec. A malfunctioning brake system allowed it to roll free. The train gathered speed, derailed and exploded, sending balls of fire rolling through downtown.

Rescue crews were forced to pull back after reporting temperatures so extreme that village streets burst into flame. Tom Harding, one of the rail workers accused of negligence, described the scene in a recorded phone call played at the trial. "Everything's on fire from the church all the way down to the metro," Harding said. "Flames are 200 feet high, it's incredible, you can't believe it here."

Prosecutors argued that Harding and two coworkers, Richard Labrie and Jean Demaitre, could have done more to prevent the accident. The men pleaded not guilty. Many critics in the U.S. and Canada argued they were scapegoats, with the lengthy trial diverting attention from lax government regulations and from cost-cutting decisions made by the Montreal Maine and Atlantic Railroad.

Tom Walsh, a lawyer for Harding, told the Associated Press his client was too emotional to speak but feels relieved. "He always admitted his responsibility. His only claim was that the responsibility was not the equivalent of criminal negligence," Walsh said. "He's very marked by this experience and he will always feel a tremendous moral responsibility and he will never be able to rid himself of that feeling."

The U.S.-owned railroad declared bankruptcy after the accident and its American officers haven't faced criminal charges. In the years since the disaster, regulators in the U.S. and Canada have tightened rules for how hazardous materials, including crude oil, are handled by railroads.

The biggest change is a gradual phase-out over the next decade of tens of thousands of single-hulled DOT-111 tank cars. The U.S. National Transportation Safety Board had issued numerous warnings before the Lac Megantic disaster that the cars are too fragile to carry "dangerous products." Despite those concerns, they continue to serve as a workhorse for railroads serving oil, gas and chemical industries.

The village of Lac Megantic, meanwhile, has struggled to recover from the disaster. The community of 6,000 people had to build a new downtown area from scratch because the historic commercial district was heavily contaminated by heavy metals and other pollution released during the blaze.

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