Tuesday marked the 80th anniversary of a deadly — and often forgotten — disaster in Hawaii that prompted major reforms in the U.S. military.

On May 21, 1944, sailors, Marines and soldiers were working on several vessels docked at West Loch loading weapons and supplies to support Operation Forager, the invasion of the Japanese-occupied Mariana Islands.

That day there were 34 Landing Ship Tank troop carriers in the waterway. The vessels were 327 feet long and about 50 feet wide. Jim Neuman, official historian for Navy Region Hawaii, said “each of these transports were combat loaded, they were floating ammunition dumps, floating gasoline storage tanks, floating vehicle garages, floating repair yards, and (also) overcrowded hotels.”

Troops loaded supplies onto the boats throughout the day, but at 3:08 p.m. something caused an explosion aboard LST-353 near its bow. The blast killed servicemen on board and rained burning debris on nearby vessels. The debris ignited fuel and munitions stored on their decks, setting off an explosive chain reaction.

By the time the smoke cleared, explosions and debris had destroyed six LSTs, killing at least 163 people and injuring 396 — though some historians suspect shoddy record-keeping by Army officials in a rush to keep Operation Forager on track could have as many as 100 more uncounted.

The military ordered a press blackout. Four days after the incident, officials released a notice acknowledging an explosion had occurred causing “some loss of life, a number of injuries and resulted in the destruction of several small vessels.”

Those who lived were ordered not to mention the incident in letters home or to even speak of it, and the event remained classified for years after. But eight decades later, sailors at Pearl Harbor and local veterans took a boat to West Loch to lay a wreath and drop lei to pay their respects to those who died.

“Like a lot of people, I had no knowledge of the disaster that occurred at West Loch 80 years ago today,” said Lt. Cmdr. Michelle Dugan, commanding officer of Navy Munitions Command Pacific’s East Asia Division Unit. “It wasn’t until I receive orders here that I knew that anything happened here.”

About a third of the casualties that day were Black members of the Army’s segregated 29th Chemical Decontamination Company.

During the war Black troops were often assigned menial tasks. But menial tasks could be dangerous. Though there’s no definitive explanation for what caused the explosion on LST-353, it’s generally believed that the explosion was caused by a mortar round as troops moved heavy explosive munitions onto the boats.

“We were expendable back in those days, and so that’s why a lot of times we’d get tasked with things where they wouldn’t risk white lives,” said Michael Myers, a Black Navy veteran and member of the American Veterans’ West Loch Post.

During the disaster some of the vessels managed to navigate their way to safety. Others were abandoned and allowed to drift in the channel, leaking oil. The oil spread across the water and caught fire as flaming debris rained down, igniting piers and the shoreline. There were three main explosions, and as Neuman described, the third explosion sent “showers (of) burning metal and debris over more than 1,000 yards, (creating) a massive mushroom cloud and dangers not only to the ships, but the ammunition depot itself.”

Miraculously, none of the munitions on land ignited, but the falling debris still killed service members on land. Neuman said that “even as they’re running on the shore, there are accounts of this shrapnel hitting them on the shore. You’ve actually got casualties from those who got off of their LST tried to get to safety, but they were actually killed by the shrapnel that’s hitting ashore.”

The fires raged for more than 24 hours before tugboats and salvage ships from Pearl Harbor managed to contain the spreading fires.

Two months after the West Loch disaster, another munitions explosion at Port Chicago in California killed 320 sailors and wounded 390, most of them Black. Survivors at Port Chicago mutinied a month later as they protested continued unsafe conditions.

The West Loch and Port Chicago disasters led the Navy to change the way it handled munitions, as well as played a key role in spurring desegregation of the military. But the West Loch disaster would remain secret until the military finally declassified all files on the incident in 1962.

The dead in West Loch who were too badly burned or mutilated to be identified and lacked dog tags were buried at 36 grave sites at the National Memorial Cemetery of the Pacific at Punchbowl. The headstones were originally marked simply “Unknown” but have since been updated with the inscription “Unknown, West Loch Disaster, May 21, 1944.”

Sailors at Pearl Harbor have marked the anniversary over the years by going to the site, but the COVID-19 pandemic led to a temporary suspension of the commemorations. But eight decades later, local veterans have insisted on ensuring the tragedy is remembered.

Theo Alexander, a Navy veteran and commander of the AMVETs West Loch Post, said that the fact the military covered it up for so long meant that many in Hawaii simply forgot. Local veterans groups and the Obama Hawaiian Africana Museum have been working to bring the disaster back into the public consciousness.

Alexander noted that one of the challenges to commemorating the disaster is that “we’re still on base, so the public didn’t have access. So next year we will try to do a little bit better.”