Unexploded ordnance
Also written: UXO
Bombs, shells, mines or torpedoes found on the seabed or washed up, and the operations to remove or destroy them.
Large amounts of munitions from both World Wars and later conflicts remain on the seabed, in dump sites and where they fell. Fishermen trawl them up, construction work uncovers them, and storms move them. Warnings announce the find, a keep-clear radius, and later the disposal operation — often a controlled detonation.
The Baltic, the North Sea and the approaches to many ports report ordnance regularly. A disposal warning usually cancels the find warning; neither establishes that the wider area is free of ordnance.
What the archive shows
1,499 messages in this archive use “Unexploded ordnance”, the earliest issued 1989-04-17 and the latest 2024-04-18. None of them is in force in the latest lists we collected. A hazard reported again and again counts once per message.
The largest yearly count is 2002, with 178 messages. Collection is incomplete between 2024-05 and 2026-08-17, so 2024 is not comparable with fully collected years.
Ordnance accounts for 1,475 of 1,499 recorded messages (98%), the largest warning type group in this selection.
Located messages that use it fall in 44 sea areas; the most frequent are North Sea (212), North Atlantic Ocean (154) and North Pacific Ocean (119).
Messages that use it are issued most often in June (194 across all years) and least often in December (79).
By warning series: HYDROLANT 780, HYDROPAC 532, NAVAREA XII 88 and NAVAREA IV 80, and 2 more.
Messages using it, by year of issue
By month of issue, all years
Where it appears · 44 sea areas
- North Sea 212
- North Atlantic Ocean 154
- North Pacific Ocean 119
- Persian Gulf 88
- Philippine Sea 66
- Adriatic Sea 58
- Tyrrhenian Sea 57
- Greenland Sea 34
- Sea of Azov 32
- Japan Sea 28
- Black Sea 25
- Arabian Sea 25
How it reads in recent messages
- HYDROPAC 1272/24 · Ordnance · Philippine Sea2024-04-18
WESTERN NORTH PACIFIC. GUAM. DNC 12. 1. UNDERWATER ORDNANCE DETONATION 2300Z TO 0600Z DAILY 23 AND 24 APR IN 13-16.20N 144-22.80E. 2. CANCEL THIS…
Underwater ordnance detonation 2300Z to 0600Z daily 23 and 24 apr in 13-16.20N 144-22.80E → - HYDROLANT 1632/23 · Ordnance · Bay of Biscay2023-07-20
BAY OF BISCAY. FRANCE. DNC 08. UNEXPLODED ORDNANCE IN 44-28.00N 001-56.33W.
Unexploded ordnance in 44-28.00N 001-56.33W → - HYDROLANT 1435/23 · Ordnance · Bay of Biscay2023-06-26
BAY OF BISCAY. FRANCE. DNC 08. UNEXPLODED ORDNANCE IN 44-23.00N 001-46.00W.
Unexploded ordnance in 44-23.00N 001-46.00W → - HYDROLANT 1361/23 · Ordnance · Bay of Biscay2023-06-19
BAY OF BISCAY. FRANCE. DNC 08. UNEXPLODED ORDNANCE IN 44-25.00N 001-52.00W.
Unexploded ordnance in 44-25.00N 001-52.00W → - NAVAREA XII 282/23 · Ordnance · North Pacific Ocean2023-05-13
CALIFORNIA. 1. UNDERWATER ORDNANCE DETONATION 160800Z TO 161700Z MAY IN AREA WITHIN ONE MILE OF 33-01.73N 118-35.32W. 2.…
Underwater ordnance detonation 160800Z to 161700Z may in area within one mile of 33-01.73N 118-35.32W → - NAVAREA XII 269/23 · Ordnance · North Pacific Ocean2023-05-06
MEXICO. CALIFORNIA. 1. UNDERWATER ORDNANCE DETONATION 111500Z TO 112200Z MAY IN VICINITY OF 32-40.66N 117-09.19W. 2. CANCEL THIS…
Underwater ordnance detonation 111500Z to 112200Z may in vicinity of 32-40.66N 117-09.19W → - HYDROPAC 979/23 · Ordnance · North Pacific Ocean2023-03-23
WESTERN NORTH PACIFIC. GUAM. DNC 12. 1. UNDERWATER ORDNANCE DETONATION 302200Z TO 310600Z MAR IN AREA WITHIN THREE MILES OF 13-35.97N 144-55.64E. 2.…
Underwater ordnance detonation 302200Z to 310600Z mar in area within three miles of 13-35.97N 144-55.64E → - HYDROPAC 868/23 · Ordnance · North Pacific Ocean2023-03-16
WESTERN NORTH PACIFIC. GUAM. DNC 12. 1. UNDERWATER ORDNANCE DETONATION 162200Z TO 170300Z MAR IN AREA WITHIN THREE MILES OF 13-35.00N 144-55.00E. 2.…
Underwater ordnance detonation 162200Z to 170300Z mar in area within three miles of 13-35.00N 144-55.00E →
Earliest in the archive
- NOAAORR-6691 · Spills · North Pacific Ocean1989-04-17
U.S. Army 87th Explosive Ordnance Detachment; San Rafael, California. San Rafael, California. 1. While pursued by the U.S.…
Army 87th explosive ordnance detachment; san rafael, california →
Often in the same message
Related terms
- Mines and mine danger areas
- Sea mines reported adrift or found, and areas where mines are known or suspected to remain.
- Anchoring and fishing prohibited
- Ships may pass but must not anchor, trawl or put gear on the seabed — usually because of cables, pipelines, moorings or ordnance.
- Safety zone / exclusion zone
- An area ships must stay out of, or may only enter with permission, for safety or security.
Warning types that use it
Counts cover the messages in this archive that use the term, recounted 2026-09-24; see coverage for what is collected and since when. Not for navigation — follow official NAVAREA and coastal broadcasts.