WACO, TX (ABC NEWS) - A fire and chemical explosion at a Texas fertilizer plant in a small town north of Waco, Texas, injured at least 179 people, destroyed dozens of homes and prompted widespread evacuations.
The blast Wednesday evening at the West Fertilizer Plant in West, Texas, caused fatalities, officials said, but early this morning they would not estimate how many.
"At this point, we don't know a number that have been killed," said Sgt. William Patrick Swanton of the Waco Police Department. "I will confirm there have been fatalities."
West, Texas, EMS Director Dr. George Smith, himself injured, said that though he had not personally seen bodies to confirm deaths, he believed the blast killed at least two emergency responders to a fire at the plant before the initial explosion and a person at a nearby apartment complex that suffered serious damage.
In addition, some responders to the fire before the explosion were believed unaccounted for, according to Smith, Swanton and West Mayor Tommy Muska.
Officials early this morning were going door-to-door searching for survivors in the blast zone to evacuate them.
They also were concerned about potentially dangerous ammonia fumes emanating from the plant, as well as forecast winds that could spread chemical fumes in new directions today.
Buildings in a radius of about five blocks around the plant were heavily damaged -- perhaps 75 homes or more, officials said.
"It was almost tornadic in effect," Swanton said. "It looked like to me one home would be fine and next to it there would be extreme devastation."
Witnesses reported heavy fire or concussive damage to a middle school, homes and an apartment complex near the plant, as well as to a nursing home, where more than 130 residents were evacuated, according to Muska.
State Trooper D.L. Wilson of the Texas Department of Public Safety described the initial fertilizer plant blast as "massive -- just like Iraq, just like the Murray Building in Oklahoma City. The same kind of hydrous [ammonia] exploded, so you can imagine what kind of damage we're looking at."
Such chemicals also could pose a breathing risk.
"What you see with high-level ammonia exposure is damage to your eyes, to your throat, to your nose, to your esophagus when you swallow," said Dr. Richard Besser, ABC News' chief health and medical editor.
The lingering danger came on top of the actual blast, which burned buildings, knocked down people, blew out windows and, according to Wilson, left the apartment complex looking like "just a skeleton standing up."
It even registered as a 2.1 magnitude earthquake, according to the U.S. Geological Survey.
"It's total chaos," West City Councilwoman Cheryl Marak said soon after the blast, according to ABC News Radio. "There's ambulances and fire trucks and police cars from everywhere."
Marak told ABC News that the explosion killed her pet dog and destroyed her house approximately 2 1/2 blocks from the plant, as well as houses around it.
"With the explosions, the whole street lifted up," she told ABC News. "It was like a massive bomb went off. It demolished both my houses -- my mother's and mine."
"I think everything around us is pretty much just gone," she added, according to ABC News Radio.
Keith Williams, a local resident, said his house also was destroyed.
"All the ceilings are out," Williams said, according to ABC News Radio. "The windows are out. The brick's knocked off the house. My big garage out back is half blowed in."
He also saw "people with all their houses tore up across the street from me, on each side of me."
By 3:30 a.m. ET, hospitals near the blast site reported treating 179 people, with 10 more being triaged. At least 24 patients at the hospitals were in critical condition and 38 in serious condition.
Hillcrest Baptist Medical Center in Waco, Texas, had more than 100 of the patients and was assessing approximately 10 more in the triage area, according to David Argueta, vice president of operations.
Patients from the blast also were confirmed early Thursday at Providence Healthcare Network in Waco, Parkland Hospital in Dallas, and Scott & White Memorial in Temple, Texas.
The fertilizer plant exploded around 7:50 p.m. local time Wednesday, according to the Texas Department of Public Safety.
Emergency response audio told the story of the chaos among firefighters and others at the scene.
"We need every ambulance we can get this way," said one snippet. "A bomb just went off. It's pretty bad."
"Firefighters down," said another. "There has been an explosion."
"The rest home has been seriously damaged. We have many people down. Please respond."
There were subsequent explosions around 10 p.m., ABC News affiliate WFAA reported. The cause of the explosions was unconfirmed, but a dispatcher was heard warning crews to move away from chemicals in unexploded tanks.
Though most fires were contained early Thursday, officials said, they continued to burn.
"It was smoldering still and it still is active," Wilson said around 1 a.m. ET. "You know other ingredients [are] at the facility, so we don't want that to explode again. So right now we can't get firefighters in there. We're worried about people right now, not property.
"We're gonna go back in and do another house-to-house search and see if anybody else, victims, are in the houses," Wilson said. "That's going to be going on all night."
The town of West has a population of about 2,800.
ABC News' Leezel Tanglao, Clayton Sandell and Elizabeth Stuart contributed to this report.