Transcript for Families Return Home After Train Derailment in North Dakota
We move onto that massive train explosion in north dakota, firefighters battling the flames and frigid temperatures at the same time. Families in that town are just now being allowed home but with major questions over what that train was hauling. Here's abc's alex perez. Reporter: More than 24 hours later the massive fire is still smoldering after a train derailed. It rattled the house and the doors and the windows were shaking. Reporter: With toxic dark plumes covering, authorities urging residents of the town of 2400 to get out. No casualties but this is the third explosion in the last six months involving trains carrying crude oil from in north dakota. In november a 90 car train derailed and last july 47 people were killed. The string of accidents raises questions. It's not a matter of if but when. Reporter: Activists question the condition of the cars used to transport oil. We're using old and outdated rail cars to move massive volumes of crude oil. Reporter: That investigation could lead to changes in rail safety and change in how north dakota crude oil is handled and transported. The good news, those evacuation orders have been lifted and the residents have been allowed to return home. Next this evening to the emergency mission in the antarctic, three rescue attempts
This transcript has been automatically generated and may not be 100% accurate.