Clarification: An earlier version of this story substituted the word “said” for the word “and” in a sentence naming the divers. This version has been updated.

An aerial view of the Aberdeen "super pond" which is deep enough to hold a 14-story building. (Courtesy of U.S. Army)

The Navy divers knew it was a risky operation. The Aberdeen “super pond” was deep enough to hold a 14-story building. Its water was black and cold. And the bottom was a tangle of muck and debris.

An Army diver had died there a month earlier. And now, with some crucial equipment broken, James E. Reyher and Ryan Harris had to make the dive with scuba gear, and little margin for error.

Even for a quick “bounce” dive, scuba tanks would give them only about 11 minutes of air to go down 150 feet and get back up. It was only a training evaluation, but no Navy scuba dive had gone below 130 feet in years.

The two men were asked if they wanted to make the dive. They could say no. But they thought that might affect their standing and their coming deployment. So Reyher and Harris entered the frigid water that day last winter and began their descent.

On Monday, a court-martial was to begin for a Navy supervisor in connection with the deaths of Reyher, 28, and Harris, 23, on Feb. 26 in the man-made pond at the Army’s test center, in Aberdeen, Md.

(The Washington Post)

The two divers, tethered to each other and to a surface line, apparently got caught on something below. By the time they could be hauled up by frantic comrades, they had run out of air and drowned, according to a Navy investigative report.

The incident unfolded in minutes, as colleagues on the surface realized the two might be stuck, then watched as the bubbles floating up increased dramatically and then stopped. Someone asked if this was part of the evaluation. It wasn’t.

“In hindsight the dive . . . should not have been undertaken,” Capt. Holiday Hanna, a Navy investigating officer, concluded. “The plan . . . did not allow the divers sufficient air or time in the event of unforeseen problems.”

But Navy divers are said to live by a “hooyah” code — a stubborn, can-do attitude in which nothing is deemed impossible.

“Navy divers can accomplish anything,” Cmdr. Michael Runkle, who headed the unit to which Reyher and Harris belonged, wrote in an essay 10 months before the accident.

“When handed a roll of duct tape and a snorkel and tasked to repair an aircraft and recover a downed plane, the Navy diver says ‘Hooyah’ and gets it done,” Runkle wrote. “Divers never say ‘can’t.’ ”

The defendant, Senior Chief Diver James C. Burger, who is charged with dereliction of duty, is accused of failing “to ensure established diving procedures and safety requirements were adhered to, as it was his duty to do so,” according to his charge sheet.

Burger denies the charge.

“This was a tragic accident, not a crime,” his lead defense counsel, Navy Lt. Cmdr. John F. Butler, wrote in an e-mail. “Senior Chief Burger steadfastly maintains his innocence and looks forward to clearing his good name.”

The court-martial of a second supervisor in the case is tentatively scheduled for next week, and several other senior divers who were at Aberdeen have received administrative punishments.

Military diving, by its nature, can be hazardous, and the smallest miscue can lead to disaster.

Reyher, a diver first class, from Caldwell, Ohio, and Harris, a diver second class, from Gladstone, Mo., were among five divers for the military who perished on duty over a 17-month period between January 2012 and last June.

One of them, former Marine George H. Lazzaro Jr., 41, was diving for the Army in the super pond when he died last Jan. 30.

“I’m losing air!” he yelled over a communication link. He surfaced too fast, passed out and sank to the bottom. It took rescue divers 21 / 2 hours to find his body.

Two other Navy divers died during that period.

Robert N. Dotzler, 24, died while free diving during an operation at the Navy base in Guam. He had apparently hyperventilated before the dive, lost consciousness underwater and drowned.

Petty Officer 2nd Class Taylor Gallant, 22, died Jan. 26, 2012, during another training operation while diving from a Canadian warship off the coast of North Carolina.

Reyher and Harris belonged to an underwater salvage unit. Gallant was an underwater bomb technician, the Navy said. Dotzler, a diver third class, was in the repair department of a submarine tender.

Such diving often is done in harsh conditions, in which divers are asked to find and work on things such as sunken ships and downed aircraft.

Perhaps the most famous such effort came in the salvage operations after the attack on Pearl Harbor during World War II. There, divers had to work in befouled waters, inside sunken battleships, amid dead bodies and unexploded bombs.

The Virginia Beach outfit that Reyher and Harris belonged to — Mobile Diving and Salvage Unit 2 (MDSU2) — in modern times has worked on the wreck of the space shuttle Challenger and has helped raise the massive turret of the sunken Civil War ironclad USS Monitor.

It used the super pond to train and evaluate its divers.

The unit’s commander, Runkle, was fired following the accident.

The Navy said that even before the tragedy it had been looking into the command climate at MDSU2, where it found poor morale, a lack of leadership and, later, safety issues.

In his essay, Runkle had been urging divers to be a little less can-do and a little more assertive in asking for more and better equipment.

The Army, for its part, closed the super pond indefinitely.

The body of water, which is 1,070 feet long and shaped like a frying pan, had been carved out of the east bank of Harford County’s Bush River in the early 1990s at the site of an old bomb-testing range.

Among many things, it was used to test the impact of underwater explosions on ship components.

The Army says the pond can handle a blast equal to 4,100 pounds of TNT — about the size of the truck bomb used to wreck the Oklahoma City federal building in 1995.

In December 2012, the pond was used to test a new device that was deployed from a helicopter to find and blow up underwater mines. The test had gone well. The tragedies came in the aftermath. The following account of the deaths comes from military reports.

A foot of visibility

The water temperature was a frigid 39 degrees with visibility less than a foot on Feb. 26 as Reyher and fellow diver Haamid Abdul-Mutakallim watched the scuba gear being set up.

The dive was supposed to have been done with Mark 16 re-breather units, which recycle air and allow more time underwater. But two of the four Mark 16s were broken, and three had to be working for a dive to be made.

The drill called for a dive to locate the carcass of an old helicopter. The water was pitch black at the bottom, where there was more than a foot of muck and a tangle of debris.

The divers would need flashlights and wire cutters.

Abdul-Mutakallim, who had never descended below 90 feet in scuba gear, testified later that he and Reyher realized the dangers of making the dive — hazardous conditions and not much air.

It was high risk for low reward, he said at a Navy investigative hearing convened before Hanna.

A dozen or so divers from the salvage unit had arrived at Aberdeen the day before, Feb. 25, to undergo final evaluation after several months of training.

If all went well, they could be deployed in April.

But the Army had closed the pond after the death of its diver the previous month. And Army officials did not know why the Navy divers had come to Aberdeen, according to Hanna’s investigate report.

After discussions, the Army granted permission for the evaluation to proceed the next day.

According to the Navy report, on Feb. 26, the Navy divers were briefed about Lazzaro’s death.

He had been one of four scuba divers who had descended in two-man teams to 127 feet to help retrieve a weight that had been used in the December anti-mine test, the Army said in a recent report on his death.

That dive was supposed to be brief, about 10 minutes, to prevent the need for a decompression stop on the way back up. The divers had a wireless communications link to the surface and to each other.

They had worked on the weight and were headed back when, at about 60 feet, Lazzaro shouted that he was losing air. Another diver told him to “blow and go,” meaning surface immediately, despite the risk of decompression sickness caused by rapid ascent.

Seconds later, Lazzaro popped to the surface and tore off his diving mask. Someone yelled, asking if he was okay. “No!” he replied, then sank again.

It was hours before they found his body in 53 feet of dark water and hauled it to the surface with a rope.

The Army report, which blacked out the cause of the accident for public release, said Lazzaro had fatal air bubbles in his lungs, heart, brain and blood vessels from his abrupt ascent. He was pronounced dead at a hospital.

No more bubbles

In February, the air and water were colder, the Navy dive was to be deeper, but the outcome would be the same.

At first, the idea of using scuba gear was rejected because, as the divers knew, it left little margin for error. Plus, the Navy’s normal scuba working limit was 130 feet.

“Not a good idea,” one diving supervisor said. “Do the math.”

A third option was to make the dive with air supplied from the surface through hoses.

But Runkle, the unit’s commander, had urged his men to “train like we fight,” be aggressive and make more deep scuba dives, the Navy report said.

One of the evaluators suggested that the divers reconsider scuba. The dive was short. There was a recompression chamber on hand. And the divers would be tethered to each other and to the surface.

It seemed like a safe exercise.

Although Navy rules said scuba dives below 130 feet could be conducted only in cases of “operational necessity,” none of the divers seem to have realized that did not include training, the report said.

The men were asked if they wanted to make the dive. Abdul-Mutakallim testified that he and Reyher knew of a diver who declined to make a dive during training and suffered unspecified “backlash.”

Plus, most of the divers thought they had to pass the super pond evaluation to be deployed.

Everybody said yes, they wanted to make the dive.

The first two divers to go down from the tending boat reached only 100 feet before the line linking them to the surface became “rats nested,” or tangled.

Their surface tender, Chief Navy Diver John O’Donnell, yanked the line four times to abort the dive, and the two men surfaced.

Reyher and Harris were next.

Their dive supervisor, Fernando Almazan, a 14-year Navy veteran and a diver first class, had calculated that the men would have 11 minutes of air, not enough time to survey the sunken helicopter.

But it should be enough to see if they could spot the wreck and come back.

Almazan instructed them to start back up four minutes after they submerged. Ascending would require five minutes. He told them to stay on schedule and not touch the bottom.

Reyher and Harris, each wearing a wet suit and a single air tank, began their descent.

At the 3:30 mark, O’Donnell gave them four pulls to abort the dive and got what appeared to be four pulls in reply. But he was confused. He told Almazan he wasn’t sure “what they just gave me.”

O’Donnell hauled in about 20 feet of the tending line. Bubbles rising to the surface suggested the divers were coming up.

Suddenly, the tending line went tight. The more O’Donnell pulled, the tighter it got. He realized that if the divers were snagged, pulling would make it worse. Or maybe they were swimming down to free themselves. So he fed out some line.

Almazan told him to stop. The bubbles coming to the surface began to increase alarmingly. Almazan asked an evaluator in the boat if this was part of the drill. The answer was no.

The Navy report suggested that the increased bubbles could have been air rushing from the scuba tank regulators malfunctioning in the cold water or the divers breathing heavily because they were running out of air.

Almazan directed Navy Diver Third Class Austin Noone, who was standing by with O’Donnell in the boat for emergencies, to go down and help.

Noone, who had never done a 150-foot dive in scuba gear, made it to 100 feet, but he, too, got tangled in the tending lines and was pulled up.

Reyher and Harris had now been underwater 12 to 15 minutes. No more bubbles were coming to the surface.

The Navy report is silent on the emotion of the moment, which must have been extreme among the tight-knit group of divers.

Almazan was in contact with Senior Chief Diver Burger, who was Reyher’s and Harris’s supervisor and was observing with alarm from shore. Burger, too, was being evaluated, according to someone with knowledge of the case.

Almazan said that there had been “an incident” and that he needed more rescue divers.

He told Burger to call 911. Burger rushed to the scene in a second boat, according to the person with knowledge of the case.

As the anguished seconds ticked by, two more divers were sent down. But they reached only 120 feet before they had breathing problems and ran out of allotted time.

Finally, by pulling the tending line in a different direction, Reyher and Harris were brought to the surface. Harris came up first. He had the tending line wrapped around one arm.

Fellow sailors got them out of their gear — Reyher’s was covered in mud — and started CPR. Both men were rushed to the recompression chamber. Harris was later taken by helicopter to a local hospital where he was pronounced dead.

Reyher was already deceased.

The super pond today

Last week, an Army spokeswoman said the super pond is still closed and may remain so until spring.

But early last month, four unarmed ordnance items were removed from the bottom as part of a cleanup. The Army did much of the work but needed the Navy’s help.

A diver was required to go down and see that some connections were sound, a Navy spokesman said.

The job fell to MDSU2.

An earlier version of this article substituted the word “said” for the word “and” in the reference to James E. Reyher and Ryan Harris in the second paragraph.