From the fall of 1944 until early 1945, the Japanese began launching fire balloons from the island of Honshu. These balloons were made of Japanese paper filled with hydrogen and explosives, and were meant to go with the jet stream and fly to North America where they would detonate. The plan was very ineffective and only a few made it to North America, however 6 Americans were killed in 1945 in a single explosion of a fire balloon.
Months before the atomic bomb decimated Hiroshima, the United States and Japan were locked in the final stages of World War II. The United States had turned the tables and invaded Japan's outlying islands three years after Japan's invasion of Pearl Harbor. That probably didn't mean much to a Sunday school teacher, her minister husband, and five 13 and 14 year old students near Klamath Falls, Oregon. Reverend Archie Mitchell was driving the group along a mountainous road on the way to a Saturday afternoon picnic. Teacher, Elyse Mitchell, who was pregnant, became sick. Her husband pulled the car over and began speaking to a construction crew about the fishing conditions as his wife and the students momentarily walked away. They were about a hundred yards from the car when she shouted back, "Look what I found dear." One of the road crew workers later said, "There was a terrible explosion, twigs flew through the air, pine needles began to fall and dead branches and dust and logs went up in flames and smoke." The minister and the road crew ran to the scene. Jay Gifford, Edward Engen, Sherman Shoeman, Dick Patzke and their teacher (Mrs. Mitchell) were all dead, strewn around a one foot hole.
The six were victims of Japan's fire balloon campaign. Carried aloft by 19,000 cubic feet of hydrogen and born eastward by the jet stream, the balloons were designed to travel across the Pacific to North America, where they would drop incendiary devices or anti-personnel explosives. Made of rubberized silk or paper, each balloon was about 33 feet in diameter. Barometer operated valves released hydrogen if the balloon gained too much altitude, or dropped sandbags if it flew too low.
All in all the Japanese released an estimated 9,000 fire balloons. At least 342 reached the United States, some as far as Nebraska. Some were shot down; some caused minor damage when they landed but no injuries except the casualties in Oregon. One hit a power line and temporarily blacked out the nuclear weapons plant at Hanford Washington. But the only known casualties from the 9,000 balloons and the only combat deaths from any cause on the U.S. mainland were the five kids and their Sunday school teacher going on a picnic.