Overview:
After seven years of painstaking underwater work, Japan Mine Action Service has cleared more than 80 tons of decaying WWII depth charges from Palau’s Helmet Wreck — but lingering toxic residue and unexploded ordnance continue to pose serious risks beneath the sea, JMAS Palau Representative Shimada Masato warned.
By: Laurel Marewibuel
KOROR, Palau (Monday, Dec. 15, 2025) — Clearing the Helmet Wreck took JMAS -Japan Mine Action Service divers seven grueling years and hauled more than 80 tons of deteriorating World War II depth charges from Palau’s coastal waters — many already leaking toxic picric acid into the sea.
The JMAS Palau Representative Mr. Shimada Masato, speaking after the operation’s completion, described the hidden dangers that made the job treacherous. “It’s kind of difficult because it’s quite easy to remove the depth charge itself,” he said. “But we are always concerned about that toxic acid — picric acid. It’s quite heavy compared with seawater, so it always stays under the water on the seabed.”
Picric acid, a volatile explosive filler, clung stubbornly to the wreck in Malakal Harbor, complicating removal amid poor water flow. “It’s quite difficult to move the seawater around it,” he noted. While not as immediately explosive as the charges themselves, the residue poses long-term risks. “It’s much safer now than before … but there’s still picric acid residue, so people should be concerned about that.”
He advised caution for recreational divers: “If you think it’s very dangerous, then please don’t go into such a deep seabed. Just look around from above.”
With the wreck now safe for tourism, the JMAS representative turned to Palau’s broader UXO crisis. Melekeok Bay and surrounding waters — sites of fierce WWII naval battles — remain littered with unexploded ordnance from sunken Japanese ships bombed by Americans.
“It’s one of our challenges in the future,” he said. “There are so many UXO still remaining in the water, particularly in the Melekeok Bay area where Japanese navy ships were sunk. We’re searching every day. Sometimes we find them.”
The team commits to ongoing hunts “until there’s nothing left to find,” underscoring Japan’s enduring partnership with Palau to neutralize wartime scars threatening fishermen, boaters and divers across the Pacific.