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What caused the explosion on the USS Iowa?

What caused the explosion on the USS Iowa?

A photo taken from the bridge captures the explosion of the No. 2 16-inch gun turret aboard the battleship USS IOWA (BB-61). It was later determined that 47 sailors were killed by the blast, which occurred as the IOWA was conducting routine gunnery exercises 330 miles northeast of Puerto Rico. Pieces of the center gun can be seen flying through the air in the photo.

The USS Iowa (BB-61) was the lead ship of the last class of battleships built by the U.S. Navy, and was the first of four in that class to be commissioned, on 22 February 1943. Although the Japanese super-battleships Yamato and Musashi were heavier and had larger guns (nine 18.1-inch) the Iowa-class (Iowa, New Jersey, Missouri, and Wisconsin) were without doubt the most sophisticated battleships ever built, with a primary armament of nine 16-inch guns in three triple turrets.

Iowa’s first brush with potential disaster occurred on 14 November 1943 as she was transporting President Franklin D. Roosevelt, Secretary of State Cordell Hull, and the entire Joint Chiefs of Staff (Admiral Leahy, General Marshall, Admiral King, and General Arnold) across the Atlantic to attend the Tehran Conference to meet with British Prime Minister Winston Churchill and Soviet dictator Josef Stalin. During the course of several anti-aircraft and other battle drills, the destroyer USS William D. Porter accidentally fired a live torpedo at Iowa.

Master Chief Stephen Skelley (center, facing camera). Iowa‘s Turret Three is in the background.

After several attempts via flashing light, Porter’s skipper, Lieutenant Wilfred A. Walter, broke radio silence to warn Iowa, which took evasive action and opened fire on the torpedo, exploding it 3,000 yards in Iowa’s wake. (Porter has been credited with a number of other incidents and accidents while escorting Iowa, at least some of which appear to be apocryphal, and, contrary to legend, her skipper was not relieved after being suspected of trying to assassinate the President: Walter retired as a rear admiral. What was true, however, is that when meeting up with other ships, Porter would be routinely greeted by “Don’t shoot. We’re Republicans” [FDR was a Democrat.] Porter was sunk off Okinawa in June 1945 when she shot down a Japanese kamikaze and the plane’s bomb exploded directly under the ship. Although there were no deaths among the crew, the ship could not be saved despite three hours of valiant damage control.)

During the surface action off the Japanese stronghold at Truk on 16 February 1944, Iowa and her sister New Jersey (with Vice Admiral Raymond Spruance embarked) assisted in sinking the Japanese light cruiser Katori and dodging several Japanese torpedoes in the process. She wasn’t quite as lucky during a bombardment of the bypassed Japanese-held island of Mili in the Marshall Islands in March 1944, when she was hit by two 4.7-inch shells from a plucky Japanese shore battery, but damage was negligible. Iowa suffered minimal damage during Typhoon Cobra in December 1944 and, near the very end of the war, bombarded steel mills on the Japanese home islands of Honshu and Hokkaido. Iowa also served as the flagship for Admiral William F. Halsey during the formal Japanese surrender in Tokyo Bay on 2 September 1945. Iowa’s skipper, Captain John McCrea, had a dog named Vicky (short for Victory), credited with being the first American dog to go ashore in Japan after the surrender.

Iowa was decommissioned in 1949 during the precipitous U.S. post–World War II drawdown (the Navy’s budget was cut by over 75 percent). However, upon the North Korean invasion of South Korea in June 1950, Iowa was brought out of reserve and re-commissioned on 25 August 1951. She then served in the Korean War, firing over twice as many shells at North Korean and Chinese positions (in Korea) as she had during World War II. She was decommissioned again in 1959. However, with the Reagan administration’s plan (led by Secretary of the Navy John Lehman) to build back up to a 600-ship Navy (reversing the post-–Vietnam War drawdown), all four Iowa-class battleships were brought out of mothballs and upgraded with Harpoon anti-ship missiles, Tomahawk land-attack cruise missile, Vulcan-Phalanx close-in-weapons systems (CIWS), and other upgraded radar, communications, and electronics. The battleships still retained their three triple 16-inch main battery turrets and most of the secondary 5-inch/38-caliber dual purpose mounts.

Iowa undergoing modernization in 1983

Iowa was re-commissioned on 28 April 1984, the second of the four to do so (New Jersey had been re-commissioned briefly during the Vietnam War—1968–69—and had a head start). Nevertheless, the years had taken their toll, and Iowa had numerous challenges being brought back into service. The required board of inspection and survey (INSURV) inspection was delayed for two years, and when it did take place in March 1986, the lead inspector, Rear Admiral John D. Bulkeley (World War II Medal of Honor PT-boat skipper), identified so many material deficiencies that he recommended that Iowa be taken out of service immediately. Secretary Lehman overruled the recommendation, but directed that the discrepancies on Iowa and her sisters be fixed. Lessons from Iowa’s re-commissioning definitely aided those of Missouri and Wisconsin.

On 10 March 1988, Captain Fred Moosally assumed command of IowaIowa’s master chief fire controlman and the gunnery officer convinced Moossally to allow experimentation with long-range gunnery shoots. Such experimentation had been authorized by an individual at Naval Sea Systems Command who was not authorized to do so, the fact of which Moosally was misled. In January 1989, in one of the experiments off Vieques, Puerto Rico, a 16-inch shell fired from Iowa achieved a distance of 23.4 nautical miles, ostensibly a record for a conventional 16-inch shell. The turret officer in Turret 1 reportedly considered these experiments to be unsafe and Turret 1 refused to participate, a fact of which Mossally was also unaware.

Captain Moosally was in command when Iowa departed Norfolk on 13 April 1989 to participate in FLEETEX 3-89, with Commander Second Fleet Vice Admiral Jerome Johnson embarked. At 0930 19 April 1989, Iowa was located 260 nautical miles northeast of Puerto Rico in the open ocean for a main battery gun shoot. According to plan, Turret 1 was to fire first, but suffered a misfire. Moosally then ordered Turret 2 to load and fire a three-gun salvo, which was not in accordance with SOP that the misfire should be resolved first. The left and right guns on Turret 2 reported being ready to shoot, but a series of communications via phone circuit indicated that there was an undetermined problem with the center gun and that it was not ready. There are quotes of what was said that can be found in different sources on the web; however, they are not contained in the official investigation reports.

The following description of what happened are excerpts taken verbatim from the third endorsement to the investigating officer’s report, signed by Chief of Naval Operations Admiral Carlisle Trost on 31 August 1989:

 “On 19 April 1989 a rapid series of three explosions within turret II aboard USS IOWA (BB 61) resulted in the instantaneous deaths of 47 American Sailors. A Judge Advocate General’s Manual investigation was convened immediately. Every conceivable source of ignition and every aspect of USS IOWA’s condition and shipboard routine that might have bearing on the incident were evaluated: procedures, training, safety, manning, and personal conduct. Since the primary explosion was determined to have occurred within the center gun room, the focus of the investigation was properly directed to that location. The tragic loss of personnel within turret II and adjacent ammunition handling spaces precluded a precise causal determination since the personnel most knowledgeable of actions and intentions were those who lost their lives….

“The initial explosion was caused by premature ignition of five bags of smokeless powder contained within the center gun with the breech open. The point of ignition was most probably between the first and second bags. Exhaustive technical tests have ruled out the following possibilities which constitute the most logical inadvertent causes: burning ember, premature primer firing, mechanical failure, friction, electromagnetic spark, propellant instability, and personal procedural error. Although deficiencies in training documentation, weapons handling procedures, and adherence to safety procedures were found within the weapons department, the exhaustive tests and duplication of the type of blast that occurred have conclusively demonstrated that these shortcomings did not cause the explosion….

 “Confronted with evidence that brought into question a possible wrongful act, the Naval Investigative Service (NIS) conducted an exhaustive investigation into the backgrounds and recent behavior of not only the center gun room personnel but of all relevant USS IOWA crewmembers….

Next, the powder bags are rolled from the two-tiered powder hoist (top) into the spanning tray.[16]

 “Additional hard factual evidence such as the position of the projectile/powder rammer and the subsequent delay in retracting the rammer to allow closing the breech provides credibility to the theory that an intentional human act caused the ignition of the powder charge. The critical controlling station within turret II to allow the aforementioned factors to occur was the center gun captain. These factors, when combined with circumstantial evidence associated with the individual manning that gun captain position at that the time of the explosion, strongly suggest that an intentional human act most probably caused the premature ignition.

“The combination of these factors leads me reluctantly to the conclusion that the most likely cause of the explosion was a detonation device, deliberately introduced between the powder bags that were rammed into the breech of the center gun. This caused premature detonation and subsequent disastrous explosions aboard USS IOWA on 19 April 1989, resulting in the deaths of 47 sailors, including GMG2 Clayton Hartwig. I further concur with the investigating officer and subsequent endorsers that the preponderance of evidence supports the theory that the most likely person to have introduced the detonation device was GMG2 Hartwig.”

The CNO’s endorsement included discussion of an analysis by the FBI of trace foreign material found in the center gun barrel of Turret 2, which the Navy investigation assessed to be evidence of an electrical igniter/timer of a type that could be purchased at an electronics store. Although the CNO’s letter described the FBI analysis as “inconclusive,” the FBI had actually determined that the elements were not consistent with an electronic igniter, but were probably from the “Break-free” solvent used to help dislodge the projectile from the barrel. In addition, on 28 August 1989 (two days before the CNO’s endorsement), technicians at Naval Weapons Support Center, Crane, confirmed the FBI’s analysis that no electrical timer, batteries, or primer were involved. The Navy’s theory then shifted to the use of a chemical igniter, which was also, much later, disproven.

The CNO’s endorsement also cited testimony obtained from an Iowa sailor under intense Naval Investigative Service (NIS, now NCIS) interrogation that implicated Gunners Mate (Guns) 2nd Class Hartwig in the explosion, but was subsequently recanted by the sailor, a fact of which CNO was possibly unaware, as that testimony was used in multiple subsequent hearings without acknowledging it had been recanted.

The second endorsement to the investigating officer’s report, signed by Commander in Chief U.S. Atlantic Fleet Admiral Powell F. Carter on 11 August 1989, included the statement, “Exhaustive testing and evaluation has virtually ruled out any of these discrepancies as directly causing the deaths of the 47 crewmembers in Turret II. Nevertheless, the number and egregiousness of the discrepancies create an impression of laxity and disregard that will cloud the investigation in the minds of non-expert critics for the foreseeable future.” Admiral Powell’s concerns were exactly on the mark.

Finally, the rammerman, at left, operates a lever which uses hydraulics to ram the powder bags into the gun’s breech. The spanning tray is then folded out of the way and the breech block is closed and locked.

Shortly after the explosion, Commander Naval Surface Forces Atlantic Vice Admiral Joseph S. Donnell appointed Rear Admiral Richard D. Milligan to conduct a Judge Advocate General Manual Investigation (JAGMAN) of the event. Milligan was a former commanding officer of Iowa’s sister ship, New Jersey. The choice of a JAGMAN investigation proved to be a problem, once it became apparent that a criminal act might have been the cause of the initial explosion, something for which a JAGMAN is not intended, since a JAGMAN allows such things as unsworn testimony.

Rear Admiral Milligan went aboard Iowa on 20 April 1989 to commence his JAGMAN investigation as recovery operations were continuing in Turret 2. Unfortunately for Milligan’s investigation, the location of bodies and body parts had not been accurately recorded or photographed before they were removed, and much damaged material from Turret 2 had already been discarded over the side with no record, which effectively compromised what would become a “crime scene.” One discrepancy that would occur between official Navy reporting and other reporting was the location of where the body of the gun captain (Hartwig) of the center gun was found.

In Milligan’s report, he also states that, “The investigation into and the analysis of all potential causes of this tragic explosion have been complicated by the issue of improperly loaded munitions in the center gun (NALC D881 projectile with five full charge bags from NALC D846 vice six), lack of an effective and properly supervised assignment and qualification process, and poor adherence to explosive safety regulations and ordnance safety. While none of these factors have been determined to be the cause of the explosion, or provide an ignition source, they cast the proper operation of gunnery systems in USS IOWA (BB 61) in a very poor light and generate doubt.”

What the above means is that the center gun in Turret 2 (and the other guns as well) were firing an unauthorized non-standard load. The projectile was a 2,700-pound shell (NALC D881). D-846 powder (NALC D846) was powder from 1943–44 that was designed and intended for use with 1,900-pound shells. In fact, the D-846 powder bags were marked, “Warning: Do not use with 2,700 LB projectiles.”

Among other things, Milligan would discover that all the gun turrets were significantly undermanned, and of those many were significantly lacking in experience. Of 51 positions in Turret 2 that called for PQS- (personnel qualification standard) qualified personnel, only 13 were manned by PQS-qualified personnel (and Turret 2 was in better shape than the other two turrets in this regard). Of the four personnel manning the center gun, all but the gun captain lacked experience, and the rammer man had never done a live gun shoot before, nor did he have any experience ramming a non-standard powder load. Hartwig had been taken off the watch bill due to his impending change of station orders, and was only ordered back on the watch bill as center gun captain the night before due to concern about the lack of experience of the center gun crew.

Iowa‘s Number Two turret is cooled with sea water shortly after exploding.

Milligan also discovered that the ram in the center gun had been over-extended by 21 inches, but it was not possible to confirm the speed with which this had been done. (The ram had a higher speed for ramming the projectile and slower speeds for ramming the powder bags.) This would become a factor in later investigations.

Milligan’s report would further state, “Despite extensive testing, no anomalies which could have served as an accidental source of ignition have been found in either hardware or ammunition components. There is strong evidence however, to support an opinion that a wrongful intentional act caused this incident.” In the “Opinions” section of Milligan’s report, he states in Opinion # 56, “wrongful intentional act was most probably committed by GMG2 Hartwig.”

Suspicion fell on Hartwig very quickly after his family informed Navy and political leaders that he had taken out a $50,000 double indemnity life insurance policy (pays $100,000 in the event of an accident) with the beneficiary being another sailor on Iowa who was a friend. Not mentioned in Milligan’s report (or any of the endorsements) was that the policy had been taken out more than two years before the event. Nevertheless, this launched a formal NIS investigation of Hartwig and other Iowa crewmen. NIS was initially reluctant to do so, since mixing a formal criminal investigation with an “informal” JAGMAN investigation was problematic, but the Vice Chief of Naval Operations, Admiral Leon “Bud” Edney, gave the go-ahead.

The NIS investigation of Hartwig gave some additional cause for suspicion. Besides the life insurance policy, Hartwig possessed a couple magazines (such as Get Even: a Guide to Dirty Tricks) which reportedly included information on how to make explosive devices, and he had experimented with explosive devices and detonators in the past. He also reportedly frequently talked about different ways of dying, had a fascination with ship disasters, had had a falling out with his close friend, had attempted suicide in high school, and had discussed in the weeks before the accident that he wanted to die in the line of duty and be buried at Arlington National Cemetery. NIS also enlisted support from the FBI, which produced a document called an “equivocal death analysis,” which cast further suspicion on Hartwig’s mindset. (Hartwig’s family and some of his friends would dispute some of these allegations, such as Hartwig being suicidal.)

Navy pallbearers, attended by an honor guard, carry the remains of one of the victims from the turret explosion after its arrival at Dover Air Force Base on 20 April 1989.

Although the official Navy documents do not mention “homosexual affair,” the series of leaks to the media from Navy sources that began in early May 1989 certainly did. According to the leaks (and subsequent reports on NIS lines of questioning), the working assumption was that Hartwig had deliberately placed an electronic device between the first and second powder bags (the origin of the first explosion) as a suicidal act due to a homosexual affair (with the life insurance beneficiary) gone bad. However, no actual evidence of a homosexual affair was found. One Iowa sailor, under intense NIS questioning, implicated Hartwig, but then recanted his testimony as soon as he was asked to sign. (Nevertheless, this recanted testimony shows up in later documents and congressional testimony without reference to it being recanted.) By the time Milligan submitted his JAGMAN report on 15 July 1989, this “theory” had been reported in multiple media stories sourced by the press to leaks from Navy officials.

The commander of Naval Surface Forces Atlantic (COMSURFLANT), Vice Admiral Joseph Donnell, endorsed Milligan’s report on 28 July 1989. Donnell recommended against judicial action or detachment for cause with respect to the commanding officer and executive officer, but that the numerous deficiencies would be documented by way of special reports of fitness.

In paragraph 10 of Donnell’s endorsement, he states “No living human being will ever know with unassailable certainty what happened in Turret II to initiate the tragedy, but the sheer weight of evidence leads in only one direction…direct and deliberate human intervention during the loading process.” Donnell’s endorsement also stated that “strong forensic evidence exists” to support human intervention as the cause. This forensic evidence would subsequently be challenged. All of the endorsements to Milligan’s report (SURFLANT, CINCLANTFLT, and CNO) expressed profound shock and incredulity that a deliberate human act could have been the cause of the explosion, yet all expressed the opinion that all other possible causes had been studied and exhausted and, therefore, a deliberate human act was, regrettably, the only conclusion.

Navy pallbearers, attended by an honor guard, carry the remains of one of the victims from the turret explosion after its arrival at Dover Air Force Base on 20 April 1989.

On 7 September 1989, Milligan and the Vice Chief of Naval Operations, Admiral Edney, briefed reporters on the results of the investigation, laying out key elements of the case against Hartwig including displaying the two publications, Getting Even and Improvised Munitions Handbook that had been in his possession. The VCNO acknowledged that there was no proof of homosexual relations and denied that leaks to the press had come from Navy sources. The briefing included the announcement that the investigation had determined that the Iowa-class battleships were safe to operate, and that the powder was stable and safe to use. Things went downhill from there.

Some of the press accused the Navy of scapegoating a dead man to cover up serious operational and safety deficiencies in the Iowa-class battleships, which were being rushed into service. Many family members of the dead sailors took issue with the Navy’s findings, not the least of which was the family of GMG2 Hartwig. Many news stories were extremely negative, and criticism from congressional quarters rapidly increased and led to several congressional inquiries and hearings, with the first commencing in November 1989.

In particular, Senator John Glenn of Ohio (former U.S. Marine pilot and Mercury astronaut) requested that the Government Accounting Office (GAO) conduct an independent review of the Navy’s findings. On 11 December 1989, Captain Moosally testified that he believed the initial explosion was intentional, but he disagreed with Milligan’s conclusion that Hartwig was the perpetrator (in his later retirement speech, Moosally would slam the investigation as having been in a rush to judgment to blame an individual and thereby let the Navy off the hook for the numerous manning and material shortfalls that plagued his ship). Senator Sam Nunn announced that the Sandia National Laboratory in New Mexico had agreed to a GAO request to assist in the independent investigation. In early March 1990, the House Armed Services Committee issued a report, “USS IOWA Tragedy: An Investigative Failure,” which was not surprisingly highly critical of the Navy.

Portrait: US Navy (USN) Rear Admiral (RDML) (lower half) Richard D. Milligan (uncovered)

The Sandia independent technical inquiry commenced on 7 December 1989. Sandia determined that the “strong forensic evidence” that a chemical igniter had been used (which became the leading theory after the electronic timer/igniter theory had been rejected) was extremely doubtful, and that the chemical traces used as evidence were actually a by-product of normal salt-water corrosion. It also quickly came to light that the Navy’s previous “over-ram” tests had not used actual powder bags, but rather bags of wooden pellets with powder at both ends. Sandia then proceeded to conduct drop tests of actual powder bags to simulate an over-ram scenario and, on the 18th test (24 May 1990), the powder exploded, destroying the test apparatus. Some Navy technical experts argued that the drop tests were irrelevant and did not accurately simulate a true over-ram scenario (or explain exactly how such an over-ram would have occurred).

However, because of the test explosion, Admiral Frank Kelso, the new CNO, ordered on 30 June 1990 that a second Navy investigation be conducted, led by Captain Joseph Miceli of Naval Sea Systems Command (NAVSEA) working in cooperation with Sandia. There were “conflict of interest” objections to Miceli’s appointment due to his significant involvement in the first investigation (and for having been in command of Naval Weapons Center, Crane, where the powder had been stored and prepared for use), but Admiral Kelso ruled that Miceli’s particular expertise was compelling.

Over-ram tests continued using actual powder and full scale mock-ups in June and July of 1990. In one test, an explosion occurred in the breech. Additional over-ram tests produced four more powder explosions. In November 1990, the un-fired projectiles from Turret 2’s left and right guns were finally found, after they had been inexplicably lost during the first investigation. Tests on the missing shells revealed the same iron fibers and chemicals as were found on the center gun projectile, further negating the chemical igniter theory.

Iowa‘s Turret Two center gun (the same one which later exploded) is loaded to fire in 1986 during a drill. First, a 1,900-pound (860 kg) shell is moved from the shell hoist cradle into the spanning tray to be rammed into the gun breech.

On 3 July 1991, Miceli briefed the NAVSEA Technical Oversight Board, reaffirming the conclusion of the first Navy investigation that no “accidental” cause for the initial explosion could be found. This conclusion appeared to be reached based on very technical discussions that centered on the position of the ram in the center gun. The Sandia tests appeared to show that a high-speed over-ram of 24 inches could produce an explosion in some bags of powder, but the ram was found over-extended at 21 inches. There was no good explanation for how such an over-ram might have occurred (unless it too was deliberate).

There had been reports of rams in Turret 2 “taking off” (i.e., an uncontrolled ram event), which produced sparks, but Milligan’s previous investigation could find no record of such events in Iowa’s maintenance logs (although given the confirmed incompleteness of other Iowa documentation related to Turret 2, it is difficult to imagine that this would have been taken as definitive proof that such events had not occurred). Sandia submitted their final report to the Senate in August 1991. The GAO concluded that an over-ram–caused explosion was a “previously unrecognized safety problem.”

On 17 October 1991, Admiral Kelso held a press conference in the Pentagon. Kelso noted that the Navy had spent $25 million and almost two years on the two investigations. Kelso stated, “The initial investigation was an honest attempt to weigh impartially all the evidence as it existed at the time. And indeed, despite the Sandia theory and almost two years of subsequent testing, a substantial body of scientific and expert evidence continue to support the initial investigation that no plausible accidental cause can be established.” Kelso added that the Navy had also found no evidence the explosion had been caused intentionally. There was no “clear and convincing proof” that GMG2 Hartwig was to blame. Kelso offered “sincere regrets” to the family of Hartwig and apologies to those who died “that such a long period has passed, and despite all efforts no certain answer regarding the cause of this terrible tragedy can be found.”

Iowa’s Number 2 turret was sealed and not used for the duration of her service. She was decommissioned on 26 October 1990, as by then Secretary Lehman was gone, and the battleships had been deemed too expensive to man and operate, especially since the fall of the Soviet Union suggested a 600-ship Navy was no longer needed. Nevertheless, Wisconsin and Missouri deployed to the Arabian Gulf for Operation Desert Storm and, during January and February 1991, the two battleships fired 1,182 16-inch rounds at Iraqi targets without mishap. (Numerous procedural improvements resulting from the Iowa investigation had been incorporated before Desert Storm.) However, by the time of the CNO’s comments in October 1991, IowaNew Jersey, and Wisconsin were already decommissioned, and Missouri would be in several months.

Written by US Navy Admiral Sam Cox

Primary source for this H-gram is the official U.S. Navy Investigation and endorsements by SURFLANT, CINCLANTFLT, and CNO, which can be found here and here. (I find it intriguing that the official reports posted at redact the names of the CNO, CINCLANTFLT, COMSURFLANT, and the lead JAGMAN investigator—which are all a matter of public record—and many others, yet mentions the names of those sailors who were accused or questioned during the investigation.) Also consulted was the GAO Report to Congressional Requestors of January 1991, “Battleships: Issues Arising from the Explosion Aboard the U.S.S. Iowa.” Numerous contemporary news accounts were also consulted. Alternative non-official views that are highly critical of the U.S. Navy investigation include A Glimpse of Hell: The Explosion on the USS Iowa and its Cover-up by Charles C. Thompson (1999) and Fall From Glory: The Men Who Sank the U.S. Navy, by Greg Visteca (1997).

What caused the explosion on the USS Iowa?