Let me start the blog with a favorite around here. 

 

This happend to a major oil and gas company back in 1999.

 

Gas from the flash gas compressor entered the domestic water system through a water fill-line. The compressor was taken off-line March 17 to repair broken belts on the water pump and re-started March 20. At 9:05 a.m., the scrubber LSH alarmed. The Automated Systems Technician (AST) drained the liquids between the LSH and LSL and restarted the compressor. At approximately 9:50 a.m. a galley hand noticed yellow water entering both washing machines. She closed the door to the laundry room and left the washing machines in the fill/on position. She notified the operation assistant of the problem. The AST drained clear water from the bottom drain valve on the domestic water tank. He ran yellowish brown water from the galley faucet. The AST turned on the outside sink faucet at 10:05 a.m. and found the same condition as in the galley, but he also smelled gas. At 10:08 a.m., both the AST and EHS technician were walking towards the door to the living quarters when an explosion occurred in the laundry room. They smothered the flames using a piece of the ceiling tile. The activation of a smoke detector on the 1st floor of the living quarters caused a fire detection system alarm. The suspected ignition source is either the washing machines or clothes dryers. All personnel were quickly accounted for after the incident. Producing operations were shut down and all utilities to the living quarters were shut off. All non-essential personnel were flown to Morgan City. The remaining essential crewmembers disconnected the domestic water system from the production process and flushed it to remove the gas and hydrocarbons from the piping.

 

This is taken almost word for word from the MMS report. This is a classic example of why backflow prevention is so important.