An explosion shattered the fertilizer plant in a rural Texas town, flattened blocks of homes and businesses, and left as many as 15 dead and more than 160 injured, officials said Thursday morning.

Hours after the explosion tore through the heart of West, Texas, a town of about 2,800 people in the north central portion of the state, hundreds of firemen and first responders were still battling the remnants of the blaze at the West Fertilizer Co. As dawn broke, officials worried about weather and stench from the chemical fire.

“They are still getting injured folks out and they are evacuating people from their homes,” Waco police Sgt. William Patrick Swanton said early Thursday morning.

“At some point this will turn into a recovery operation, but at this point, we are still in search and rescue,” he said.

Even as evacuations and triage continued, officials estimated the number of injured at more than 160, some of whom were in serious condition. West Mayor Tommy Muska told reporters that his city needs the prayers of everyone.

“We’ve got a lot of people who are hurt, and there’s a lot of people, I’m sure, who aren’t gonna be here tomorrow,” Muska said. “We’re gonna search for everybody. We’re gonna make sure everybody’s accounted for. That’s the most important thing right now.”

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.

“It was like a nuclear bomb went off,” Muska said. “Big old mushroom cloud.”

The death toll was between five and 15 people, according to authorities who stressed that was still a fluid count. As many as five volunteer firefighters were unaccounted for.

The number of injured had been steadily increasing since the explosion around 8 p.m. on Wednesday. Many had been evacuated to hospitals as far away as Dallas.

There is no indication that the blast was anything other than an industrial accident, but the area was being treated as a crime scene, a routine precaution. The explosion stunned the region, eerily coming almost exactly 20 years after the massacre in Waco, about 20 miles away. Seventy-six members of the Branch Davidians died in 1993 after a 50-day siege of their compound. April 19 is also the anniversary of the bombing of the Alfred P. Murrah Federal Building on Oklahoma City where 168 people were killed in 1995.

The fire was reported at about 6 p.m. at the factory, and volunteer firefighters immediately responded, But they faced a difficult job because of the danger from the chemicals, including ammonia, used in the production of fertilizer.

By 8 p.m. the plant exploded, turning a radius of four city blocks into a flattened zone, according to City Councilman Al Vanek. He told reporters that the inner circle was “totally decimated.”

The property damage was fierce including at least 50 to 75 houses. An apartment complex with about 50 units was stripped to its skeletal support, according to video from the scene. A middle school was hard hit.

The West Rest Haven Nursing Home was in the danger zone and firefighters said they had evacuated more than 130 patients, mainly in wheelchairs.

The force of the explosion was heard dozens of miles away and witnesses, interviewed by local television, repeatedly compared it to an earthquake.

Mayor Muska was among the firefighters and said the explosion knocked off his fire helmet and blew out the doors and windows of his nearby home.

The main fire was under control as of 11 p.m., authorities said. By dawn Thursday there was lingering smoke and the stench of chemicals still in the air.

About 100 of the injured were treated at Hillcrest Baptist Medical Center in Waco, where five people were in intensive care. Another 65 were taken to Providence Health Center in Waco. Officials said the injuries included broken bones, bruises, lacerations, respiratory distress, and some head injuries and minor burns.

There were no immediate details available from police on the number of people who work at the plant, which was cited by the Texas Commission on Environmental Quality in 2006 for failing to obtain or to qualify for a permit. The agency acted after receiving a complaint in June of that year of a strong ammonia smell, according to The Associated Press.