For those of you who may have heard press reports about Navy ships decontaminating from fallout in Japanese waters, here's what's happening.

Since the Cold War, Naval vessels have been equipped with decontamination systems consisting of high pressure spray nozzles and pipes strategically located all over the weather decks. The idea was that in the event of a nuclear, biological, or chemical attack, the crew would be ordered to strike below, the ship would be made airtight and sea water (from deep below the surface) would be pumped through the system, flushing any loose contaminants over the side. We used to drill this all the time, just to exercise the equipment, and it was pretty spectacular, completely wreathing the ship in mist. Specially equipped and clothed crews would then go out on deck with soap, water, fire hoses and brushes and scrub down all exposed decks, bulkheads and gear. NBC warfare specialists would monitor the ship with NBC detectors until the all-clear was sounded.

There were obvious limits to the effectiveness of this, of course, but some response was better than none. And in the event of a real emergency, it probably would have been good for morale.