Four workers suffered burns after a grain-dust explosion at an Arizona pet-food plant Sunday.
KSAZ reported that one of the workers was in critical condition as a result of the blast at the Nestle-Purina plant in Flagstaff. Two other workers were released from the hospital, while the condition of the fourth is unknown.
Flagstaff Fire Dept. Captain Bill Morse said that the four men were welding on the fifth floor of the complex's seven-story grain elevator when their torches sparked grain dust and set off the explosion at around 5 p.m. local time.
On weekends, production is halted in the complex's grain elevator so workers can carry out maintenance projects, he said.
The explosion, which was short and did not produce a long-lasting fire, blew out metal doors at the front of the grain elevator, said Morse, who added that he did not know the name of the contracting company for which the men worked. Fire officials told KSAZ that a blast panel in the grain elevator contained the explosion and prevented a possible building collapse. The station reported that at least a dozen other workers were in the building at the time.
Other parts of the Nestle Purina complex were unaffected by the explosion, Morse said.
The U.S. Occupational Safety and Health Administration website says grain dust is the main source of fuel for explosions in grain handling.
The Associated Press contributed to this report.