Fire crews battled a blaze at a gas plant about an hour east of Calgary Friday morning. The local fire department near the Village of Hussar, Alta., was the first to respond to the Canadian Natural Resources (CNRL) plant but quickly called in the hazardous materials team. One crew from Calgary also responded to help support Wheatland County Fire Services, which responded to the fire at the CNRL facility at 5:30 a.m. Stars Air Ambulance confirmed that it transported a man in his 70s to Foothills hospital in Calgary. Early Friday afternoon, an EMS spokesperson confirmed that the injured man was transported in critical, life-threatening condition. A second worker who was onsite at the time of the incident was assessed by medical personnel and released, CNRL said in a statement to CTV News. “Canadian Natural personnel, along with local emergency response resources, actively managed the incident and the fire has been safely extinguished,” a CNRL spokesperson added. “All regulatory bodies were notified of the incident. There is no safety threat to the public or the environment.” The Calgary Fire Department said it responded with hazardous materials technicians to identify all chemical and hazardous materials. The surrounding area was evacuated as a precaution. Wheatland County issued a statement just after 6 p.m., saying that the evacuation radius had been reduced from three-kilometres to 500 metres before being reduced once again early Friday evening. “The evacuation area has been reduced to within 100 meters of the facility,” it said. “Residents who were previously evacuated, including those in Chancellor and surrounding areas, have been permitted to return home. “Fire services have cleared the scene. Site personnel continue to manage the incident, and the reduced evacuation area remains in place as a precaution.” Hussar is around 103 kilometres east of Calgary. CTV News has reached out to CNRL for comment. With files from The Canadian Press