An explosion at a fertilizer plant near Waco, Texas, Wednesday night has killed between five and 15 people and injured at least 160 after levelling a factory and several nearby buildings, police say.

"It was a significant explosion," Waco police Sgt. William Patrick Swanton said early Thursday morning.

The massive blast, which sent flames shooting into the sky and rained burning embers, shrapnel and other debris, occurred about an hour after firefighters had been called to battle a blaze at the West Fertilizer plant in West, a community about 30 kilometres north of Waco.

The explosion happened around 7 p.m. local time and could be heard as far away as Waxahachie, 70 kilometres to the north.

Swanton said there are a number of missing people including between three and five firefighters who were battling the blaze at the time of the explosion.

"It looks like when the blast occurred, the concussion pressure impact — if that’s the correct word — literally destroyed homes … around that plant," Swanton said.

In this Instagram photo provided by Andy Bartee, a plume of smoke rises from a fertilizer plant fire in West, Texas. (Andy Bartee/Associated Press)

West Mayor Tommy Muska told reporters that his city of about 2,800 residents needs "your prayers."

"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.

A search for survivors continued throughout the night, as emergency workers went house to house and business to business looking for people trapped in the rubble.

Some firefighters unaccounted for

The town's volunteer firefighters responded to a call at the plant about 6 p.m., said Sgt. Swanton. Muska was among them, and he and his colleagues were working to evacuate the area around the plant when the blast followed about 50 minutes later. Muska said it knocked off his fire helmet and blew out the doors and windows of his nearby home.

Aerial footage showed fires still smouldering in the ruins of the plant and in several surrounding buildings, and people being treated for injuries on the flood-lit local football field, which had been turned into a staging area for emergency responders.

A member of the city council, Al Vanek, said there is a four-block area around the explosion "that is totally decimated." Wilson said the damage was comparable to the destruction caused by the 1995 bomb blast that destroyed the Murrah Federal Building in Oklahoma City.

He said main fire was under control as of 11 p.m., but residents were urged to remain indoors because of the threat of new explosions or leaks of ammonia from the plant's ruins.

A fire burns in a apartment complex destroyed near the fertilizer plant that exploded earlier in West, Texas. (LM Otero/Associated Press)

Among the damaged buildings were 50 to 75 houses, an apartment complex with about 50 units that Wilson said was reduced to "a skeleton," a middle school and the West Rest Haven Nursing Home, from which first-responders evacuated 133 patients, some in wheelchairs.

'This town is hurt really bad'

Erick Perez, 21, of West, was playing basketball at a nearby school when the fire started. He and his friends thought nothing of it at first, but about a half hour later, the smoke changed color. The blast threw him, his nephew and others to the ground, and showered the area with hot embers, shrapnel and debris.

"The explosion was like nothing I've ever seen before," Perez said. "This town is hurt really bad."

The explosion happened in West, Texas, near Waco. (Google Maps)

Information was hard to come by in the hours after the blast, and entry into the town of about 2,800 people was slow-going as the roads were jammed with emergency vehicles rushing in to help.

Dozens of emergency vehicles amassed at the scene and hours after the blast, fires were still smoldering in the ruins of the plant and in several surrounding buildings. Aerial footage showed injured people being treated on the flood-lit football field that had been turned into a staging area for emergency responders.

'It was like the whole Earth shook'

Al Vanek, a West City Council member, said first-responders were treating victims at about half a dozen sites, and he saw several injured residents from the nursing home being treated at the community center.

"Tomorrow is going to be a very sad day," Vanek said.

Debby Marak told the AP that when she finished teaching her religion class Wednesday night, she noticed a lot of smoke in the area across town near the plant. She said she drove over to see what was happening, and that when she got there, two boys came running toward her screaming that the authorities ordered everyone out because the plant was going to explode.

She said she had driven only about a block when the blast happened.

"It was like being in a tornado," Marak, 58, said by phone. "Stuff was flying everywhere. It blew out my windshield."

"It was like the whole Earth shook."

She called her husband and asked him to come get her. When they got to their home about three kilometres south of town, her husband told her what he'd seen: a huge fireball that rose like "a mushroom cloud."

Lucy Nashed, a spokesman for Perry's office, said personnel from several agencies were en route to West or already there, including the Texas Commission for Environmental Quality, the state's emergency management department and an incident management team. Also responding is the state's top urban search and rescue team, the state health department and mobile medical units.

American Red Cross crews from across Texas were also heading to the scene. Red Cross spokeswoman Anita Foster said the group was working with emergency management officials in West to find a safe shelter for residents displaced from their homes. She said teams from Austin to Dallas and elsewhere are being sent to the community north of Waco.

The West fertilizer plant 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.

In 2001, an explosion at a chemical plant killed 31 people and injured more than 2,000 in Toulouse, France. The blast occurred in a hangar containing 300 tons of ammonium nitrate, which can be used for both fertilizer and explosives. The explosion came 10 days after the Sept. 11, 2001, terrorist attacks in the U.S., and raised fears at the time it was linked. A 2006 report blamed the blast on negligence.