Shaped like a teardrop and carved out of the eastern bank of the Bush River, the UNDEX Test Facility at Aberdeen Proving Ground has earned the nickname "Super Pond" for its unusual properties.
Viewed from above, the man-made pond looks much darker than the nearby waters of the Chesapeake Bay. That's because it drops 150 feet to a flat bottom, where, out of view of the public, the military tests missiles, torpedoes, sonar and the effects of explosions on submarines and boats — all within walls that can withstand the equivalent of 4,100 pounds of TNT.
It's also where Navy divers practice salvage missions. When the military isn't blowing things up in the Super Pond, it offers a controlled and easy-to-monitor environment, away from the unpredictability of nature's choppy waves and ever-shifting conditions.
"Until recently," said Maj. Gen. Genaro J. Dellarocco, chief of the Army Test and Evaluation Command, "it was one of the safest facilities we had on the installation.
"We're investigating with the Navy to find out what changed."
On Tuesday afternoon, rescue workers pulled two members of the Navy's elite Mobile Diving and Salvage Unit 2 from the Super Pond.
Diver First Class James Reyher, 28, and Diver Second Class Ryan Harris, 23 — whose unit has been involved in high-profile missions such as the recovery of the space shuttle Challenger — had been participating in a training exercise at the facility. They were reportedly using air hoses supplied from the surface, and were tethered together.
One was dead at the scene; the other was pronounced dead at a nearby hospital. They were the second and third divers to die at the Super Pond in less than a month.
George H. Lazzaro Jr., a 41-year-old former Marine working as a civilian engineering technician in the Firepower Directorate of the Aberdeen Test Center, died Jan. 30 while performing routine maintenance in the facility.
Until Lazzaro's death, Army officials said, not one injury had ever been reported at the Super Pond, which was built in 1995.
Now the Army Test and Evaluation Command has closed the facility indefinitely, pending the findings of several investigations. Lazzaro's death is being probed by the Army Criminal Investigation Command, Army Combat and Readiness/Safety Center and the Occupational Safety and Health Administration. The Naval Criminal Investigative Service is looking into the deaths of Reyher and Harris.
While officials have said little about either incident, they have stressed that they are not related.
A spokeswoman for the Army Test and Evaluation Command said the Navy was briefed on Lazzaro's death before the training exercise this week. Spokeswoman Robin Boggs said naval instructors performed risk assessments and followed safety measures outlined in the U.S. Navy Diving Manual.
Aberdeen Proving Ground, the Army's oldest active test installation, has grown from its World War I-era beginnings into one of the military's most advanced research centers, with a mostly civilian workforce of 21,000 studying, developing and engineering weapons, armor, communications and electronics.
In 1990, as public concern was growing over the impact of naval shock and vibration testing on sea life in the Chesapeake and off Key West, the military chose the base for an isolated new Underwater Explosive (UNDEX) Test Facility.
"It's a controlled environment," Dellarocco said. "We can actually explode things underwater and keep it confined to it."
At 1,070 feet long and 920 feet wide, the Super Pond can accommodate both boats and submarines. Equipment can also be dropped to the bottom. The facility is cleaned periodically, Dellarocco said.
From Day One, he said, it has been used for dive training. As such, it is familiar to members of Mobile Diving and Salvage Unit 2.
Based at Joint Expeditionary Base Little Creek-Fort Story in Virginia Beach, the unit performs the dangerous jobs of searching for underwater explosives, underwater repair, salvage and demolition. Formed in 1966, it's one of two such units in the Navy.
"We dive the world over," Navy divers boast in their motto, with some justification. Members of MDSU2 cleared the waterways of Southeast Asia during the Vietnam War, worked on the recovery of the space shuttles Challenger and Columbia, TWA Flight 800 and the Civil War ironclad Monitor, and the disaster responses to Hurricane Katrina in 2005, the 2007 Minneapolis bridge collapse and the 2010 Haiti earthquake.