The Wednesday night blast shook houses 50 miles away and measured as a 2.1-magnitude seismic event, according to the United States Geological Survey.
Massive devastation after Texas explosion
Fire officials fear that the number of casualties could rise as high as 60 to 70 dead, said Dr. George Smith, the emergency management system director of the city.
Massive emergency response to explosion
Texas officials expect heavy casualties
Woman's houses destroyed, dog killed
"That's a really rough number, I'm getting that figure from firefighters, we don't know yet," he said. "We have two EMS personnel that are dead for sure, and there may be three firefighters that are dead."