City : EPA tests have not found significant levels of chemicals in the air . The plant 's owner says an electrical fault may have caused the blaze . The plant produced chemicals used in explosives , its owner tells ABC affiliate reporters . A main chemical produced at the plant was anhydrous ammonia , an EPA official says .
City : EPA tests have not found significant levels of chemicals in the air . The plant 's owner says an electrical spark may have caused the blaze . The plant produced chemicals used in fracking , its CEO tells CNN affiliate WFAA . A main chemical produced at the plant was anhydrous ammonia , an EPA official says .