Authorities on Friday raised the count to 12 dead in the West fertilizer plant explosion . Most fatalities have been firefighters and other emergency responders who arrived on the scene first. About 200 were injured in the blast that rocked this small Texas town about 20 miles north of Waco.

Search and rescue operations are continuing as crews sift through the debris from the Wednesday explosion. By Friday morning, about 150 buildings had been scoured by emergency crews with 25 more to go. About 50 homes, three fire trucks and an ambulance were demolished as a result of the blast.

The cause of the explosion still remains unclear to the hundreds of local, state and federal authorities that have converged on the small town, population 2,800. A no-fly zone was in place over the area around the plant, and access to the area was restricted for anyone not involved in search and rescue.

An F.B.I. spokesman out of the San Antonio office has said that there was no indication of criminal activity. Other officials have said that the event is being considered an industrial accident at this time.

The tragedy began with a fire at the plant Thursday evening. Volunteer firefighters were attempting to extinguish the blaze when the explosion occurred.

A statement from President Obama pledged support from the Federal Emergency Management Agency, as well as other federal agencies, to assist state and local efforts “to make sure there are no unmet needs as search and rescue and response operations continue.”

Adair Grain Inc. owns the plant, which is operated by West Chemical and Fertilizer Co. The plant employs nine people and does not manufacture any products, instead serving as a storage facility that sells agricultural chemicals and fertilizer to farmers. Substantial amounts of anhydrous ammonia and ammonium nitrate are stored there, both chemicals used in commercial fertilizers. These two chemicals can become explosive under the proper conditions.

Late last year, in a filing with the Environmental Protection Agency, the company reported storing 540,000 pounds of ammonium nitrate and 110,000 pounds of anhydrous ammonia.

The last time the facility was inspected by the Occupational Safety and Health Administration was 28 years ago, Feb. 13, 1985. Five “serious” violations were found in that inspection, including improper storage and handling of anhydrous ammonia and improper respiratory protection for workers. There was a $30 penalty at the time for the company.

In June 2012, a fine of $5,250 was levied by the federal Department of Transportation’s Pipeline and Hazardous Materials Safety Administration for violations that also involved anhydrous ammonia. A later investigation found that those violations were corrected by the company.

If you or a loved one was affected by the tragic event at the West fertilizer plant, contact a Texas industrial accident attorney at Schechter, Shaffer & Harris, L.L.P., Accident & Injury Lawyers today to learn what your legal rights are.