SAN ANTONIO -- The La Salle County Sheriff’s Office said that it received a call around 11 a.m. regarding an ignition and fire at a tank battery.

The facility is located at the Ledwig Ranch, which is east of I-35 between Millett and Dilley. The facility is operated by Carrizo Oil & Gas.

Fire and Rescue personnel were deployed and created an exclusion zone of a quarter mile surrounding the area. Authorities said this is standard procedure and does not include residential areas or schools.

The blast extinguished itself, but authorities are continuing to monitor small fires that ignited because of the initial blast. Sheriff’s officials said since they are in an open area, they want to make sure no flames spread causing a wild fire.

Two male contractors were airlifted taken to a hospital in San Antonio. The sheriff’s office stressed that this is not an indication of their injuries; rather, it is a common practice because of where they are located.

As of Tuesday afternoon the cause of the explosion had not been determined. There was no spill associated with the explosion.