UPDATE: According to CNN: 

A massive explosion at a fertilizer plant in the small Texas town of West left at least two people dead, sent dozens more seeking medical attention and prompted a widescale evacuation in the community of 2,600 people.  Fire officials fear that the number of casualties could rise much higher.

Authorities say an explosion at a fertilizer plant near Waco, Texas, has injured several people. The West, Texas, Fire Department says the explosion happened Wednesday night at a fertilizer plant in the community north of Waco. KWTX TV is reporting :

Numerous injuries were reported and multiple ambulances were requested.  Several buildings were reported destroyed and a nearby nursing home was damaged.  There were reports that people were trapped in the nursing home and in an apartment building.

Scanner traffic indicated that some residents of both the nursing home and apartment building were severely injured.  Children are among the victims, according to reports from the scene. Two children were reported to be trapped on the second floor of the damaged apartment complex.   As many as a dozen helicopters were sent to the area and were landing at West High School stadium.

A number of buildings were reported to be burning, some in residential areas and evacuations were underway.  Authorities were going door-to-door checking residences in the area.  West Middle School was one of the buildings reported to be on fire.  Injured victims were being taken to area hospitals.  An officer was dispatched to provide crowd control at Hillcrest Baptist Medical Center in Waco, which issued a call to all staffers to report. The explosion knocked out power to a large area of the community.