The impact of the blast was so catastrophic, it destroyed Marty Marak's home, killed his dog and leveled houses for blocks around.
But he had no time for panic or grief. Marak darted right into the line of danger, even as the threat of a second explosion loomed.
Like the rest of the firefighters in the town of West, Texas, population 2,800, Marak is a volunteer firefighter.
He doesn't get paid to battle flames or save lives; he actually runs a heating and air conditioning company.
But he risks his life just to help his tight-knit central Texas city.
On Wednesday night, the valor of the volunteers was put to the ultimate test.
Firefighters were already battling an enormous blaze at West Fertilizer Co. when an earth-shaking explosion blasted windows and walls off homes. Rolling fireballs leaped into into the sky, and residents 50 miles away felt the force of the blast.
Mayor Tommy Muska -- also a volunteer firefighter -- said "it was a like a nuclear bomb went off."
The explosion devastated Marak's family.
"It demolished both the houses there, mine and my mom's, and it killed my dog," Marak's wife, Cheryl, told CNN's Piers Morgan.
But Marty Marak took off, trying to extinguish the blaze before it could trigger a second explosion at a fertilizer tank at any second.
A flood of other volunteers also scrambled to the scene, including firefighters and emergency medical personnel from hundreds of miles away, the Texas Department of Public Safety said.
With her house annihilated, Cheryl Marak took cover in her brother's home, about two miles away from town. For hours, she wondered if her husband was still OK.
"For all those people who are still there ... responders that remain ... you just worry about everybody," she said, her voice cracking.
The dread was amplified when the director of the city's emergency management system said two EMS personnel and possibly three firefighters were killed.
Finally, shortly before midnight, Cheryl Marak was able to speak with her husband and hear he was OK.
"I'm begging him to come home, to let me come and get him ... but he said he can't. He's going to stay with his guys," Cheryl said.
So the excruciating wait continued.
Rep. Bill Flores, whose district represents the town of West, said the courage of Marak in the face of loss isn't uncommon.
"That's just the way that we Texans are wired," he said. "Even though we face our own personal tragedies from time to time, we still know that we have to go help others -- and then assess our own tragedies later on."