The cause of last Friday’s spectacular fire at a St. Louis gas distribution company might never be known. The U.S. Chemical Safety and Hazard Investigation Board has had inspectors on-site all weekend and they say the cause might be difficult to find because of the extent of the damage at the Praxair Distribution center. One inspector says new safety procedures might be needed to keep such an event from happening again. Some pieces of metal were blown as far as 900 feet into a nearby neighborhood. Nobody was hurt, but homes, cars and fences were damage.