Inferno at Pearl Harbor: The 1944 Ammunition Explosion on USS LST-353

On May 21, 1944, a deadly explosion rocked the West Loch of Pearl Harbor, echoing the tragedy that had occurred at the same site two and a half years earlier. While the infamous December 7, 1941, attack by Japanese forces remains etched into American memory, the lesser-known but equally catastrophic West Loch Disaster claimed the lives of 163 sailors and wounded nearly 400 more. The explosion originated aboard USS LST-353, a tank landing ship loaded with munitions in preparation for the invasion of Saipan in the Mariana Islands. The resulting chain reaction of explosions and fires destroyed several vessels and caused significant damage. Yet for decades, this incident remained largely classified and overshadowed by other wartime events.

Background: Pearl Harbor’s Strategic Role in 1944

By mid-1944, Pearl Harbor had transformed from the site of America’s most devastating surprise attack into the nerve center of the Pacific campaign. The harbor bustled with activity, housing ships, submarines, and thousands of servicemen engaged in the ongoing island-hopping strategy to push back Japanese forces. One such upcoming operation was the invasion of the Mariana Islands, particularly Saipan, which would give U.S. forces a launching point to strike at Japan’s home islands.

In preparation, a fleet of LSTs (Landing Ship, Tank) was being loaded with vehicles, fuel, ammunition, and supplies. These massive vessels were essential for amphibious assaults, able to carry tanks and cargo directly onto beaches. But their concentrated firepower made them volatile floating powder kegs.

The Explosion: Chain Reaction of Catastrophe

On the afternoon of May 21, 1944, at approximately 3:08 p.m., an explosion erupted aboard USS LST-353, which was moored at West Loch, a lesser-used area of the harbor designated for loading such dangerous cargo. Eyewitnesses described the initial blast as sudden and massive, immediately engulfing the ship in fire and debris. The heat and force of the explosion triggered nearby vessels—many similarly laden with munitions and fuel—to catch fire or explode themselves.

Within minutes, the disaster escalated. LST-480, moored alongside, also detonated. In total, six LSTs were destroyed (LSTs 39, 43, 69, 179, 353, and 480), along with smaller craft. Fires raged for more than 24 hours, consuming ships, vehicles, and supplies that had taken months to assemble.

Casualties and Damage

The human toll was devastating:

• 163 servicemen killed

• 396 wounded

• Numerous missing, many of whom were presumed vaporized or drowned

The physical damage was staggering. In addition to the destroyed LSTs, several other vessels were severely damaged, and thousands of tons of ammunition, vehicles, and fuel were lost. It was one of the deadliest non-combat incidents of World War II for the U.S. Navy.

Investigation and Secrecy

In the aftermath, the Navy launched an investigation into the cause of the disaster. While the exact cause was never definitively proven, it was widely believed to have been sparked by the accidental detonation of a mortar round during the loading process, possibly due to rough handling or improper storage procedures.

Due to the sensitive nature of the operation and to avoid damaging morale or revealing logistical vulnerabilities, the incident was classified and kept from public knowledge for many years. It wasn’t until the 1960s that information began to emerge, and not until the 1980s that most records were declassified.

Legacy and Commemoration

Unlike the December 1941 attack, the West Loch Disaster received little attention in public discourse or popular history. There were no immediate memorials, no dramatic headlines, and few survivors who spoke out. The secrecy surrounding the event ensured it remained a “forgotten disaster” of World War II.

However, efforts to recognize the sacrifices of the men lost have grown. A memorial plaque was eventually installed at the site, and naval historians have worked to ensure the event is no longer overlooked.

In military circles, the West Loch tragedy served as a powerful reminder of the dangers of ammunition handling and the importance of strict safety protocols, especially during large-scale amphibious operations. It likely led to improved procedures in subsequent campaigns, such as the invasions of Iwo Jima and Okinawa.

Conclusion

The explosion at Pearl Harbor on May 21, 1944, underscores that the cost of war is not only borne in combat but also in preparation. The sailors who died that day were preparing for a dangerous mission thousands of miles away, yet met their fate in the harbor they believed to be safe. Remembering their sacrifice honors not only their memory but the countless others who served in dangerous logistical and support roles throughout the war. The West Loch Disaster stands as a solemn testament to the unseen risks of military readiness and the silent toll of war.

References (APA Style)

• Office of Naval Intelligence. (1981). West Loch Disaster declassified report. U.S. Navy Archives.

• Morison, S. E. (1959). History of United States Naval Operations in World War II: The Invasion of Saipan. Little, Brown and Company.

• Stillwell, P. (2006). Battleship Arizona: An Illustrated History. Naval Institute Press.

• U.S. Navy. (2020). Naval History and Heritage Command: West Loch Disaster. Retrieved from https://www.history.navy.mil