A massive explosion ripped through a fertilizer plant in the town of West, Texas, Wednesday night, sending scores of injured to area hospitals, sparking fires and triggering evacuations.

WHAT'S NEW

-- "It was like a nuclear bomb went off," West Mayor Tommy Muska said.

-- Some 10 to 15 buildings have been "totally demolished" and "probably 50 homes (were) heavily damaged," said George Smith, community emergency medical services director.

-- The fertilizer plant was near an apartment complex and a nursing home, authorities said.

-- Some people might be trapped in collapsed buildings, Smith said.

-- "I expect there's going to be many fatalities and many more injured people," he added.

-- State troopers in gas masks set up roadblocks, waving away cars coming off the highway

PREVIOUSLY REPORTED

The blast

-- A massive explosion hit the West fertilizer plant some 18 miles north of Waco, Texas.

-- At least two emergency medical personnel are dead, said EMS Director Smith.

-- Hillcrest Hospital in Waco was told to anticipate 100 injured people.

-- More than 60 patients were received Wednesday night, hospital CEO Glenn Robinson said, with victims suffering from "blast injuries, orthopedic injuries (and) a lot of lacerations. While some of the injuries are minor, others are "quite serious."

-- A number of nearby residents were being evacuated because of the possibility of another explosion, officials said.

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

The response

-- A field triage station was set up on a football field near the plant, Robinson said.

-- At least six helicopters were flying out the injured, Robinson said. Others were being transported by ambulance, and some were getting to the hospital by car, he added.

-- Aircraft flying below 3,000 feet were banned from going within a 3-mile radius of West, Texas, the Federal Aviation Administration said.

-- Hazardous material teams were being rushed to the scene, an emergency management official said.

-- Texas Gov. Rick Perry was working to get resources into the area, his spokesman said.

-- Anhydrous ammonia is a concern of those in the vicinity of the explosion,Smith said. According to the Centers for Disease Control and Prevention, anhydrous ammonia is a pungent gas with suffocating fumes that is used as a fertilizer.

-- Area residents told CNN that they were warned about the toxic substance.