Argentina's Navy announced Thursday that an “unusual” sound detected during the search for the missing ARA San Juan submarine apparently came from an explosion — an ominous development that prompted relatives of the 44 crew members to burst into tears.
The noise – which took place on Wednesday, 15 November, at 10.31am, the day the submarine was last heard from – heard in the ocean near the last known position of the San Juan was "consistent with an explosion," Navy spokesman Captain Enrique Baldi said.
"An anomalous, singular, short, violent and non-nuclear event consistent with an explosion," occurred shortly after the last communication of the San Juan and its 44 crew, Baldi told a press conference in Buenos Aires.
Balbi said the search will continue until there is full certainty about the fate of the ARA San Juan, but expectations that the crew-members will be found alive now seem to be all but extinguished.
"According to this report, there was an explosion," Balbi told reporters. "We don't know what caused an explosion of these characteristics at this site on this date."
US and specialist agencies said the "hydro-acoustic anomaly" was produced just hours after the Navy lost contact with the submarine on November 15.
The information was passed on by Rafael Grossi, Argentina’s ambassador to Austria and representative to the International Atomic Energy Agency (IAEA).
“The ambassador is also a member of a nuclear test control organisation that has a network to detect nuclear tests,” Balbi confirmed at the press conference.
Speaking to Radio Mitre, Grossi seemed to indicate that the report had come from the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO), an organisation that detects nuclear testing.
“They made a report which I conveyed to Chancellor [Jorge] Faurie and [Defence Minister Oscar] Aguad in which it said that a phenomenon was detected three hours after the last communication [from the ship."
"The technical conclusion is that it was a singular event of high intensity and that it was not consistent with [normal] marine noises or earthquakes,” he added, saying it was similar to “other underwater explosions” that had been registered in the past.
The missing submarine was originally scheduled to arrive Monday at the Mar del Plata Navy Base, about 250 miles (400 kilometres) southeast of Buenos Aires.
Relatives of the crew who have gathered at the base to receive psychological counselling broke into tears and hugged each other after they received the news.
Some, however, lashed out in anger at the Navy and the government’s response.
"They sent a piece of crap to sail," said Itati Leguizamon, wife of submarine crew member German Suárez. "They inaugurated a submarine with a coat of paint and a flag in 2014, but without any equipment inside. The Navy is to blame for its 15 years of abandonment."
The German-built diesel-electric TR-1700 class submarine was commissioned in 1985 and was most recently refit in 2014.
During the US$12-million retrofitting, the vessel was cut in half and had its engines and batteries replaced. Experts say that refits can be difficult because they involve integrating systems produced by different manufacturers and even the smallest mistake during the cutting phase of the operation can put the safety of the ship and the crew at risk.
The Argentine Navy and outside experts have said that even if the ARA San Juan is intact, its crew might have only enough oxygen to be submerged seven to 10 days.
Balbi said Wednesday that Argentine Navy ships as well as a US P-8 Poseidon aircraft and a Brazilian Air Force plane would return to the area to check out the sound, which originated about 30 miles north of the submarine's last registered position.
US Navy Lt. Lily Hinz later said the unusual sound detected underwater could not be attributed to marine life or naturally occurring noise in the ocean.
"It was not a whale, and it is not a regularly occurring sound," Hinz said.
The San Juan went missing as it was sailing from the extreme southern port of Ushuaia to the city of Mar del Plata, about 250 miles (400 kilometres) southeast of Buenos Aires.
More than a dozen airplanes and ships are still participating in the multinational search despite stormy weather that has caused waves of more than 20 feet (six metres). Search teams are combing an area of some 185,000 square miles (480,000 square kilometres), which is roughly the size of Spain.
The US government has sent two P-8 Poseidons, a naval research ship, a submarine rescue chamber and sonar-equipped underwater vehicles. US Navy sailors from the San Diego-based Undersea Rescue Command are also helping with the search.
Britain's Ministry of Defence sent a special airplane with emergency life support pods to join the hunt that includes planes and ships from a dozen nations.