Houston, Apr 18 (IANS): Many people were feared dead and dozens of people injured in a massive explosion at a Texas fertiliser plant, an incident that triggered an earthquake measuring 2.1 on the Richter scale.

A fire burnt furiously at the plant, hours after the deafening explosion Wednesday night. Emergency services say they now have the blaze under control.

The explosion happened about 7.50 p.m. in the city of West, some 320 km north of the Texas capital of Houston, reported Xinhua.

There are no official casualty figures, but George Smith, head of the Texas Emergency Medical Services in West, said at least 60 were dead and some 170 injured, broadcaster KWTX reported.

West Mayor Tommy Muska told an earlier news conference it had been confirmed at least four or five rescuers and firefighters were missing.

Muska said a fire broke out at the fertiliser plant before the explosion, which devastated surrounding areas, destroying 10 homes and damaging 50 more. It also triggered a 2.1 magnitude earthquake.

Chrystal Anthony, a nearby resident, said she saw the flames engulf the nursing home and an apartment complex.

"It was an apartment complex that was devastated, the nursing home. The fire was close to a residential area," Anthony was quoted as saying.

"It was like a bomb went off," said Barry Murry, a resident who lives about a mile away from the plant. "There were emergency vehicles everywhere. It has been overwhelming."

Witnesses said an evacuation had already begun before the explosion due to the fire at the plant. The huge explosion sounded like a nuclear bomb and sent a mushroom cloud into the air.

Rescuers launched a door-to-door search overnight in the area near the explosion, looking for dead or injured.

Toxic gas is feared to have been released into the air and authorities are worried that a second fertiliser tank may explode.

The cause of the explosion and the earlier fire in the plant is under investigation.

West is a small city of 2,600 residents. Half of the town was evacuated after the explosion.

ABC News, citing Texas Department of Public Safety spokesperson Gail Scarborough, put the number of injured at 200; 40 of them are critical.

Besides the injuries, 75 to 100 houses and business were completely destroyed in and around the plant, Scarborough was quoted as saying.

CNN said residents are being evacuated because officials are worried that another tank at the facility might explode.

Shortly after the explosion, more than 60 patients streamed into Hillcrest Hospital in Waco, suffering from "blast injuries, orthopaedic injuries (and) a lot of lacerations", said hospital CEO Glenn Robinson.

While some of the injuries are minor, others are "quite serious", he said.

At least six helicopters are going to fly out those who are injured, Robinson said. Others are being transported by ambulance, and some are getting to the hospital by car, he added.

Two other hospitals in the region were also assisting.

The West Fertilizer Plant is just north of Waco. A school and a nursing home are among the buildings near the plant, CNN affiliate KWTX reported.