On April 19, 1989, the USS Iowa experienced a devastating explosion in Turret Two during a routine training exercise in the Caribbean Sea, resulting in the tragic loss of 47 sailors.

Initial investigations by the Navy suggested sabotage by a crew member, but subsequent independent reviews by organizations like Sandia National Laboratories pointed to the likelihood of an accidental ignition due to overramming of powder bags.


The USS Iowa

The USS Iowa (BB-61) occupies a distinguished place in American naval history, embodying the pinnacle of battleship design and the strategic shift in naval warfare during the 20th century. Commissioned on February 22, 1943, the Iowa was the lead ship of her class, which represented the last and most advanced battleships built by the United States.

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These vessels were designed to combine speed, armor, and firepower in a way that had never been seen before, making them among the most formidable naval assets of their time.

During World War II, the battleship served with distinction in both the Atlantic and Pacific Theaters. In the Atlantic, she played a crucial role as a flagship, notably hosting President Franklin D. Roosevelt on his journey to the Tehran Conference in November 1943.

USS Iowa before her launch in 1942.

In the Pacific, the Iowa was instrumental in several key operations, providing gunfire support for landings on enemy-held islands and engaging Japanese naval forces. Her 16-inch guns, capable of firing shells weighing up to 2,700 pounds over distances of up to 23 miles, offered unmatched firepower that could both support amphibious assaults and engage enemy ships at long range.

After World War II, the USS Iowa was briefly decommissioned but was later recommissioned to serve during the Korean War, where she again provided invaluable naval gunfire support.

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The decision to reactivate and modernize the Iowa in the 1980s, decades after her initial commissioning, reflected the ongoing strategic value of battleships in an era increasingly dominated by missile technology and nuclear submarines. The modernization included upgrades to her armaments and the addition of modern electronic warfare systems, allowing her to serve as both a platform for traditional naval gunfire and as a command and control center in the high-tech naval battlespace of the late 20th century.

The Turret Explosion

The tragic explosion aboard the USS Iowa on April 19, 1989, unfolded against the backdrop of routine but essential naval exercises intended to maintain the operational readiness of the ship and its crew. These exercises, conducted in the Caribbean Sea near Puerto Rico, involved live-fire drills using the battleship’s main armament—its nine 16-inch guns, which were distributed among three turrets.

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Each turret was a complex piece of engineering, capable of launching shells each weighing as much as a small car over distances of up to 23 miles.

On that fateful day, Turret Two, one of these massive gun houses, was the scene of a catastrophic event. As the crew loaded the number two 16-inch gun, a series of explosions suddenly erupted within the turret’s interior. The explosions were so powerful that they instantly killed 47 of the 55 men working inside the turret, marking it as one of the deadliest peacetime accidents in the history of the United States Navy.

Turret Two on USS Iowa explodes.

The precise sequence of events leading up to the explosion remains the subject of much analysis and debate. The process of loading these guns was intricate and required the coordinated efforts of dozens of sailors, involving the manual handling of gunpowder bags and the large shells themselves.

The explosion’s cause was initially unclear, sparking extensive investigations that would delve into every aspect of the incident, from the design of the turret and its ammunition handling systems to the procedures followed by the crew.

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In the immediate aftermath, the ship’s crew was tasked with the grim and dangerous work of recovering the bodies of their fallen comrades and securing the damaged turret to prevent further accidents. The Iowa turned back to port, bearing the physical and emotional scars of the incident.

Initial Investigations

The initial investigations into the tragic explosion aboard the USS Iowa on April 19, 1989, quickly became mired in controversy, setting off a chain of events that would question the efficacy of military investigative procedures and the accountability mechanisms within the United States Navy.

The Navy’s inquiry into the incident focused on unraveling the sequence of events that led to the explosion, scrutinizing the design and operation of the turret, the handling of munitions, and the actions of the crew before the blast.

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In the immediate aftermath of the explosion, the Navy launched an exhaustive investigation to determine its cause. Investigators sifted through the wreckage, interviewed survivors, and analyzed the ship’s operational procedures.

Initially, the Navy suggested that the explosion might have been caused by a malfunction or mishap related to the handling of the gunpowder bags used to fire the 16-inch shells. However, as the investigation progressed, a more contentious theory emerged—that the explosion had been deliberately caused by one of the crew members.

This theory was based on circumstantial evidence and psychological profiles, pointing to a specific sailor who had allegedly been disgruntled and had the technical knowledge necessary to initiate such an explosion. The Navy’s assertion that the explosion was an act of sabotage rather than an accident or a result of procedural shortcomings sparked immediate controversy.

A view of the explosion from the bridge. Pieces of the turret can be seen in the air.

Critics argued that this conclusion was premature and lacked concrete evidence, suggesting instead that it was an attempt by the Navy to deflect criticism and liability for the incident.

The controversy surrounding the Navy’s findings was fueled by several factors. First, there was significant skepticism about the plausibility of the sabotage theory, given the stringent security and safety measures in place aboard the ship.

Second, the families of the victims and the public questioned the fairness and thoroughness of the Navy’s investigation, suggesting it might have overlooked or ignored evidence that contradicted its conclusions.

Finally, the Navy’s handling of the investigation and its treatment of the accused sailor’s family were seen by many as indicative of a broader institutional failure to transparently and impartially investigate the incident.

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In response to the outcry and at the behest of Congress, further investigations were conducted by independent bodies, including the Government Accountability Office (GAO) and technical experts from Sandia National Laboratories.

These independent reviews raised doubts about the Navy’s conclusions, suggesting that the explosion could have resulted from an accidental ignition of the gunpowder, possibly due to overramming of the powder bags or a static electricity discharge, rather than deliberate sabotage.

Alternative Theories into the Turret Explosion

The controversy and skepticism surrounding the initial Navy investigation into the USS Iowa explosion led to calls for independent reviews to reassess the findings and explore alternative theories about the cause of the tragedy. These independent reviews were crucial in challenging the initial conclusions and in shedding new light on the possible factors that contributed to the explosion.

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One of the most significant independent investigations was conducted by Sandia National Laboratories, a premier research and development laboratory. Sandia’s expertise in weapons systems and materials science positioned them well to conduct a thorough analysis of the explosion. Their investigation focused on the chemical and physical properties of the gunpowder used in the Iowa’s 16-inch guns, as well as the mechanical processes involved in loading and firing these massive weapons.

Sandia’s findings cast doubt on the theory that the explosion was caused by deliberate sabotage. Instead, their research suggested that a phenomenon known as “overramming” of the powder bags into the gun barrel could create conditions for an accidental ignition. The investigation pointed to the possibility that static electricity or a spark generated by the friction of the bags being rammed too tightly could have ignited the gunpowder. This theory suggested that the explosion was an accident resulting from a combination of procedural errors and possibly flawed design or maintenance of the turret’s loading mechanisms.

A ceremony for the victims families on the anniversary of the tragedy.

The General Accounting Office (GAO), an independent, nonpartisan agency that works for Congress, also conducted a review of the Navy’s investigation. The GAO’s role was to evaluate the thoroughness and accuracy of the Navy’s findings and to assess the evidence supporting various theories about the explosion. Their review included an examination of the procedural aspects of the investigation, as well as the scientific analyses that underpinned the conclusions.

The GAO report highlighted several concerns with the Navy’s investigation, including questions about the reliability of the evidence used to support the sabotage theory. The GAO pointed out that alternative explanations, such as accidental ignition due to overramming, had not been adequately considered. The report emphasized the need for a more comprehensive and scientifically rigorous analysis to determine the most likely cause of the explosion.

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The independent reviews and their findings became a focal point for congressional hearings and public discourse on the Iowa explosion. Lawmakers and the public alike were concerned about the initial rush to judgment and the potential for miscarriage of justice.

The hearings served as a forum for airing the discrepancies between the Navy’s conclusions and the findings of independent investigators, highlighting the complexities involved in determining the cause of such a catastrophic event.

The independent reviews had a profound impact on the understanding of the USS Iowa explosion. They shifted the narrative from one of deliberate sabotage to a tragedy that was likely the result of a series of unfortunate errors and procedural lapses.

This reassessment not only had implications for the families of the sailors who were killed or injured but also influenced how the Navy approached the safety and operation of its ships. The focus on alternative theories underscored the importance of comprehensive safety protocols and the need for continual reassessment of operational practices to prevent future accidents.


The immediate aftermath of the explosion required a thorough assessment of the structural and system damages within Turret Two, where the explosion occurred. The Navy undertook repairs to the damaged turret, but it was never returned to operational status. The decision was made to seal the turret, essentially leaving it non-operational for the remainder of the ship’s active service.

In response to the explosion, the Navy implemented enhanced safety measures for the handling and storage of gunpowder and ordnance. These measures were designed to prevent a similar accident from occurring in the future. There was an increased emphasis on training and safety protocols for the crew members involved in operating and maintaining the ship’s armaments.

While the focus was on repair and safety, the USS Iowa also received updates to some of its systems to improve its operational capabilities. These updates were part of the Navy’s ongoing efforts to maintain the relevance and effectiveness of its battleships during this period.

After the repairs and modifications were completed, the USS Iowa returned to service. Despite the tragedy, the ship continued its role in the U.S. Navy, participating in training exercises and operations. The USS Iowa’s return to service highlighted the Navy’s commitment to its battleships, even as the role of such ships in modern naval warfare was evolving.

However, the end of the Cold War and subsequent changes in defense priorities led to the decision to decommission the USS Iowa and her sister ships. The USS Iowa was decommissioned for the last time on October 26, 1990, just over a year after returning to service following the turret explosion. The decommissioning marked the end of an era for the Iowa-class battleships, which had served the United States in various capacities since World War II. After decommissioning, the USS Iowa was placed in the reserve fleet for some years.

In the 2000s, efforts began to preserve USS Iowa as a museum ship. These efforts culminated in the ship being donated to the Pacific Battleship Center. The USS Iowa was towed to the Port of Los Angeles in San Pedro, California, where she was opened to the public as a museum ship. The museum highlights the ship’s service history, the lives of those who served aboard her, and serves as a memorial to the sailors lost in the 1989 turret explosion.