WEST, Texas – While the West Fertilizer company has not officially released the number of victims of the blast on Wednesday, the Los Angeles Times is reporting that in an interview with the Mayor Tommy Muska of West Texas, the number believed to be dead is 35-40.

Hospitals have treated more than 160 casualties with varying injuries, according to Police sergeant W. Patrick Swanton of Waco, Texas. Some 60-75 people have been left homeless by the disaster, according to Mark Felton, director of the local Red Cross chapter.

Rescuers in Texas on Thursday combed through rubble in a painstaking search for survivors after a massive blast at the West Fertilizer plant on Wednesday. The factory exploded with the force of a 2.1-magnitude earthquake, devastating much of the small town of West and sending up a toxic cloud. The blast was felt up to 50 miles away.

On Thursday afternoon, smoke was still billowing out of the plant's ruins, a nearby house had its roof torn off, and a huge chunk of metal had been dropped in the middle of a corn field.

Much of West Texas was evacuated overnight as an acrid cloud hung over the area, and Texas Governor Rick Perry said local schools would remain closed for the remainder of the week.

"Last night was truly a nightmare scenario for that community," Perry told a news conference in the state capital Austin, announcing that he was seeking a federal disaster declaration that would make additional funds available.

"This tragedy has most likely hit every family, it has touched practically everyone in that town," Perry said.

McLennan County deputy sheriff Matt Cawthon told reporters the devastated area had been "highly populated" and was "still a very volatile situation" because of the presence of ammonium nitrate, a common but potentially explosive fertilizer ingredient.

A US National Guard contingent of 20 troops trained to aid in emergencies and incidents involving weapons of mass destruction was dispatched to the scene to monitor for hazardous emissions.

Officials said they do not yet know what caused the explosion, but are treating the factory site as a crime scene until they rule out foul play.

The West Fertilizer Co. paid more than $5,000 in fines in 2012 after being cited for mislabeled cargo tanks and inadequate transport practices, and had been cited by state authorities for a lack of permit in 2006.

The factory reportedly held large quantities of anhydrous ammonia, a pungent, colorless gas stored in pressurized tanks than can ignite in dense concentrations and under high heat.

President Barack Obama offered the prayers of the nation to the town of about 2,800 people, saying "a tight-knit community has been shaken, and good, hard-working people have lost their lives."

-Mira Obermanm,AFP

Copyright Agence France-Presse, 2013