Electrical equipment in hazardous areas the participation of operations, maintenance, safety, electrical and instrumentation professionals, the use of process diagrams and material flows, MSDS and any pertinent documents, information and knowledge to determine the hazards and their extent and the countermeasures to be employed. Area classification documentations are reviewed and updated to reflect process changes. Soon after the introduction of electric power into coal mines, it was discovered that lethal explosions could be initiated by electrical equipment such as lighting, signals, or motors. The hazard of fire damp or methane accumulation in mines was well known by the time electricity was introduced, along with the
Merrimack Valley gas explosions his smoke alarm went off; as he was extinguishing it he heard a boom from a neighbor's house and the ground shook. All of the fires were put out by 6:45pm. One man was killed when a chimney fell on his car, twenty-five others were reported injured, and Lawrence General Hospital received three patients including one firefighter. Once it was realized that the fires were being caused by over-pressurized gas mains, residents whose gas is supplied by Columbia Gas were told to evacuate their homes. There is no indication that foul play was involved. Gas services for approximately 8,000 residents