Snorkelers & Divers

The military conducted live-fire training and combat operations at sea for centuries, and some Department of Defense operational ranges impacted the sea and other water bodies. Following international practices at the time, the U.S. military and militaries of other nations disposed of excess, obsolete and unserviceable munitions at sea prior to 1970. Because of this, munitions may be encountered anywhere, not just in charted hazard areas.

While diving or snorkeling, you could encounter munitions, especially if you are exploring in an area that was part of a former range or a wartime wreck. Munitions encountered should be considered dangerous.

Help protect yourself and other divers or snorkelers, and make underwater adventures safe from explosive hazards by following the 3Rs of Explosives Safety and warning those with you to do the same:

  • Recognize – when you may have encountered a munition and that munitions are dangerous.
  • Retreat – do not approach, touch, move or disturb it, but carefully swim away.
  • Report – If offshore, report the item to your divemaster or the Coast Guard.
    – If on or near shore, call 911 and advise the police of what you saw and where you saw it.

3Rs of Explosives Safety


  • Avoid locations where munitions are present.
  • When in areas where munitions may be present, brief divers on the 3Rs and the dangers associated with munitions, just as you do for dangerous sea life and other dive-site hazards.
  • Report underwater munitions that may pose a substantial hazard to recreational divers or others to the Coast Guard or police.

For more information, read the 3Rs Pocket Card for Divers.