The Marion Fire Department Hazardous Materials Team is trying to determine what caused an explosion at the former Thomson Television Picture Tube plant that killed one worker.
Police say John Phillips, 41, of Seymour was using a blowtorch to detach a tank from the outside of the building Monday evening when the explosion occurred.
An explosion sent a fireball into the air and rattled windows blocks away.
Police say the torch may have ignited something inside the canister.
Tests will be run to determine what was in the canister. It had some labels on it, but they were weathered and unreadable.