(CNN) -- The full extent of the devastation will have to wait until the light of day Thursday. But residents of the small Texas town of West already know what to expect.
"There are a lot of people that got hurt," West Mayor Tommy Muska forewarned Wednesday night. "There are a lot of people that will not be here tomorrow."
A massive explosion at a fertilizer plant on the edge of the town killed at least two people, wounded more than 150, leveled dozens of homes and prompted authorities to evacuate half their community of 2,800.
"It was a like a nuclear bomb went off," Muska said. "Big old mushroom cloud."
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.
"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.
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"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."
Early Thursday morning, firefighters painstakingly combed through houses, many reduced to rubble.
"(It's) massive -- just like Iraq. Just like the Murrah (Federal) Building in Oklahoma City," said D.L. Wilson of the public safety department.
What caused the explosion at the West Fertilizer Co. was not immediately known. But its location -- next to an apartment complex, a nursing home and a middle school -- did not help matters.
The blast stripped the apartment complex, with 50 units, of its walls and windows. "It was just a skeleton standing up," Wilson said.
The nursing home, with 133 residents, was quickly evacuated.
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Fireball in the sky
West is a community of about 2,800 people, about 75 miles south of Dallas and 120 miles north of Austin. The town's chamber of commerce touts it as "the Czech point of central Texas."
Czech immigrants arrived there in the 1880s and the community still maintains strong ties to their central European roots, with businesses named "Little Czech Bakery" and "The Czech Inn."
The blast took place at the plant about 8:50 p.m. ET.
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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.
Brad Smith lives 50 miles away and he felt his house shake from the explosion.
"We didn't know exactly what it was," he said. "The forecast said a line of thunderstorm was going to come though. My wife and I looked up and wondered, 'Did it get here six hours early?'"
Back in West, officials painted a grim picture.
"There are lots of houses that are leveled within a two-block radius," Smith said. "A lot of other homes are damaged as well outside that radius."
The number of injuries ran well over 100, authorities said.
Five hours after the blast, carloads of the wounded continued to stream into area hospitals.
While some of the injuries are minor, others were "quite serious," said Glenn Robinson, the chief executive officer of Hillcrest Hospital in Waco.
Many suffered from "blast injuries, orthopedic injuries (and) a lot of lacerations."
Risk remains
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.
What is anhydrous ammonia
The scene
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. "
Worst-case scenario
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.
"It demolished both the houses there, mine and my mom's and it killed my dog," she said.
Other residents had similar stories.
"It was like a bomb went off," said Barry Murry, who lives about a mile away from the plant. "There were emergency vehicles everywhere. It has been overwhelming."
As they waited for daybreak, they sought comfort in Mayor Muska's words.
"This is not the end of the world," he said. "This is a big ol' cut that we got across our hearts right now."
"But," he added, "we are strong. We will rebuild."
