The shell exploded as a bulldozer was leveling a 351-acre area near Nakagusuku Bay on the southern island of Okinawa, said Takaharu Shimada, an official of the Okinawa prefectural (state) police.
The worker, identified as Kenji Shiroma, 29, the bulldozer's driver, suffered injuries to his head from several pieces of the shell, but his life was not in danger, Shimada said.
Yoshiyuki Nakahara, an official with Japan's Self-Defense Forces, said explosives experts confirmed that the shell was a 2.36-inch rocket with a white phosphorous shell, used by U.S. troops in the battle of Okinawa in the closing days of the war in 1945.
Unexploded bombs or shells have occasionally been dug up in Tokyo and other cities that faced heavy U.S. air raids in the closing days of the war.
Okinawa, about 1,000 miles southwest of Tokyo, was the final land battle of the war. A quarter of a million people died, including at least 12,500 Americans and roughly one-third of the 450,000 civilians on the island.
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