Fire officials fear that the number of casualties could rise much higher -- as many as 60 to 70 dead, CNN reported citing George Smith, the emergency management system director of the city.

The blast took place at the West Fertilizer Plant, about 18 miles north of Waco, about 8.50 p.m. Wednesday. It sent a massive fireball into the sky. Flames leaped over the roof of a structure and a plume of smoke rose high into the air.