The accident happened just north of the town of Van, about 75 miles east of Dallas.

According to Van Zandt County fire marshal Chuck Allen, a man and a woman, both 24, were smoking while sitting on top of a tank used to store a chemical and salt water mixture -- presumably for fracking. The tank they were on exploded.

Of the six tanks at the facility, three caught fire and burned. Fire departments from Grand Saline, Tyler and Lindale helped get the flames under control.

Both victims were rushed to East Texas Medical Center Hospital in Tyler, then moved to Parkland in Dallas for burn treatments. The woman is on life support, Allen says, while the man suffered burns to his face, chest, and arms.

The fire crews are letting the flames burn themselves out. A small amount of salt water and raw crude oil made its way into a small creek. Crews have installed berms to prevent further seepage.