First responders “literally lost their lives helping others” after an explosion at a Texas fertilizer plant, the state’s Attorney General Greg Abbott said Thursday.

At least 14 people are dead and more than 160 injured Wednesday night at the West Fertilizer Co. plant in West, Texas.

Many of those killed were firefighters trying to help, including 52-year-old Kenny Harris, a father of three children.

Harris, a fire captain in Dallas who lived in West, rushed towards the fertilizer plant when the fire began.

“Our first responders don’t run from harm, they run towards it,” said Abbott. “And that’s exactly what happened here.”

He vowed that those families affected by the blast would get full support from the community to rebuild their lives.

“Literally in an instant, families have been ripped apart,” Abbott told reporters at a news conference.

“But these are tough Texans, and…in the coming months and years these Texans will piece their lives back together knowing that they have unparalleled support from their state, from their community and fellow Texans.”

The massive explosion measured 2.1 on the Richter magnitude scale.

It’s still unclear what caused the fire or explosion. Ammonium nitrate was stored at the facility – it’s commonly used in farms across Canada and the U.S., but can be explosive under extreme conditions.

And while West Fertilizer Co. was fined in 2006 after local residents complained of an intense smell, there had been no further issues. The Environmental Protection Agency said there was no fire or explosive risk.

Earlier Thursday, Texas Gov. Rick Perry called the explosion at a Texas fertilizer plant a "nightmare" and said he is asking U.S. President Barack Obama to declare a state of emergency in the county.

The blast levelled a large portion of the town, destroying houses and an apartment building in a large radius around the blast site.

"President Obama called from Air Force One as he was en route to Boston and we greatly appreciate his call and his gracious offer of support, of course, and the very quick turnaround of the emergency declaration that will be forthcoming, and his offer of prayers," Perry said, speaking from Austin, Texas.

"To that end I am declaring McLellan County a disaster. We'll request an emergency declaration from the president."

The decision to officially declare a state of emergency would free up federal funding and assistance to help local officials deal with the disaster.

‘Nightmare scenario’

Perry said the disaster has affected almost everyone in West, a town of about 2,800 people. "It's truly a nightmare scenario for that community."

The U.S. National Guard is helping carry out search-and-rescue efforts in the area. As well, the Texas Department of Transportation has been brought in to handle traffic flow, the Department of Public Safety is securing the blast area for law enforcement personnel, and state experts have been brought in to monitor air quality.

Officials still don't know exactly how many people were killed or injured in the massive late Wednesday night, but estimate up to 15 people have lost their lives, Waco police spokesman Sgt. W. Patrick Swanton said earlier Thursday.

"They are still in the search-and-rescue process ... they are continuing to do that. It is a slow, methodical search at this point and they are using every resource they have to do that correctly and make sure they don't miss anything," he said.

As part of the search effort, rescuers are being forced to shore-up and reinforce some buildings before they can safely enter to look for survivors, Swanton said.

In one case, rescuers have been unable to enter a 50-unit apartment building because the structure is unstable.

"It ranges from broken windows to complete devastation. There are homes that are no longer homes," Swanton said. "The 50-unit apartment building -- as you look at the front of that complex you can see inside the apartments. Walls were peeled back, the roof was peeled back...what I would describe as severe destruction."

It's believed that between 50 and 75 houses, the apartment complex, a school and the West Rest Haven Nursing Home were either damaged or destroyed in the blast. In total 133 residents were evacuated from the nursing home.

Death toll may rise

Though officials have estimated between five and 15 people were killed, West Mayor Tommy Muska said early Thursday that number is likely to rise, noting "we have no idea at this time how many injuries or how many deaths."

"There's a lot of people that got hurt and a lot of people that I'm sure are not going to be here tomorrow so (we need) your prayers," Muska told reporters.

"This is a very strong community, we will bounce back. This is probably the most devastating thing that's ever happened to this community but we're going to build back; it's not the end of the world it's just a big old cut that we got across our heart."

Muska, who is a firefighter in addition to being mayor, was among the first responders on the scene. He said he and his colleagues were working to evacuate the area when the blast occurred.

Muska said it knocked off his fire helmet and blew out the doors and windows of his nearby home.

With a report from CTV’s Paul Workman in West, Texas, and files from Andy Johnson