Fertiliser plant explodes in Texas

An explosion has ripped through a fertiliser plant near Waco in the US state of Texas and destroyed numerous buildings including a school and nursing home, and killing at least two people and injuring more than 100, authorities have said.

Officials, however, declined to comment on number of people killed, but said the death toll was expected to rise as search teams combed through the rubble of the demolished plant and surrounding homes.

"The number is not current yet. It could go up by the minute. We're in there searching the area right now and making sure that it's safe," Dean Wilson, a spokesman for the Texas Department of Public Safety, said.

Wilson said 50 to 75 homes were damaged by the explosion and a fire that followed, and that a nearby 50-unit apartment complex had been reduced to "a skeleton standing up".

He said it will be some time before authorities know the full extent of the loss of life and damage caused by Wednesday night's blast at the plant in the town of West, about 30km north of Waco.

He said all the wounded have been taken to hospital and added that a nearby nursing home had collapsed from the explosion and that people were believed trapped inside.

Jason Shelton, 33, a father-of-two who lives less than a 2km from the plant, said he heard fire trucks heading toward the facility five minutes before the explosion.

He said he felt the concussion from the blast as he stood on his front porch.

"My windows started rattling and my kids screaming," Shelton told Reuters. The screen door hit me in the forehead ... and all the screens blew off my windows."

The blast was reported at about 8pm local time (01:00 GMT on Thursday) in West, about 130km south of city of Dallas. A dispatcher with Texas Fire Department said the explosion happened on Wednesday night.

Tommy Muska, West's mayor, said buildings in a five-block radius from the plant were severely damaged by the explosion. 

Hillcrest Baptist Medical Center in Waco reported treating 66 patients, including children, for injuries including lacerations, burns and broken bones.

"We are seeing a lot of lacerations and orthopaedic-type injuries ... things you would expect in an explosion," said David Argueta, vice president of hospital operations.

He said nine people suffering burns had been transferred to the Parkland Hospital in Dallas. A third hospital, Providence Health Center, reported receiving more than 30 patients from the disaster.

A senior official said the nursing home and much of the centre of town had been evacuated, and that residences near the explosion had been levelled.

The air in town remained thick with smoke more than two hours after the explosion, and the area around the blast site was littered with shards of wood, bricks and glass.

Governor Rick Perry issued a statement saying his office had "mobilised state resources to help local authorities" deal with the incident.

"We are monitoring developments and gathering information as details continue to emerge about this incident,'' the statement said.

A White House official said the Obama administration was aware of the situation and monitoring local and state response through the Federal Emergency Management Agency.

Gayle Scarbrough, a spokeswoman for the Department of Public Safety in Waco, told television station KWTX that DPS troopers have been transporting the injured to hospitals in their patrol cars.

She said six helicopters were also en route.