For the town, the danger may not be over.
Even though officials have turned off all the gas, they evacuated half the town because they were worried another tank at the facility might explode.
"What we are hearing is that there is one fertilizer tank that is still intact at the plant, and there are evacuations in place to make sure everyone gets away from the area safely in case of another explosion," said Ben Stratmann, a spokesman for Texas State Sen. Brian Birdwell.
If the winds turn, the other half of the town will have to be evacuated as well.
The big concern: anhydrous ammonia, a pungent gas with suffocating fumes that is used as a fertilizer.
When exposed to humans, it can cause severe burns if it combines with water in the body.
And exposure to high concentrations can lead to death.
The West Fertilizer Co. said it had 54,000 pounds of the chemical, the Dallas Morning News reported.
Early Thursday morning, state troopers in gas masks manned roadblocks, waving away cars coming off the highway.
The Federal Aviation Administration instituted a flight restriction over the town.
Authorities closed schools for the rest of the week, and urged everyone to stay away from school property.
So many firefighters and medics descended on the town to help its all-volunteer firefighting force that the public safety department issued a plea that it didn't need more assistance.
"The firefighters and EMS people are coming from hundreds of miles away to help us," Wilson said. "Right now, we are overflowing with help. "
According to the Dallas Morning News, the plant informed the Environmental Protection Agency that it presented no risk of fire or explosion.
In a report it filed with the EPA, the plant said that even the worst-case scenario wouldn't be that dire: there would be a 10-minute release of ammonia gas that wouldn't kill or injure anyone, the newspaper reported.
But what happened Wednesday night was much worse.
Tommy Alford, who works in a convenience store about three miles from the plant, said several volunteer firefighters were at the store when they spotted smoke.
Alford said the firefighters headed toward the scene and then between five and 10 minutes later, he heard a massive explosion.
"It was massive; it was intense," Alford said.
'Not the end of the world'
Cheryl Marak, who sits on West's city council, said the impact of the blast knocked her to the ground.