The Japanese air forces on Iwo Jima were losing the war of attrition brought on by the relentless 7th Air Force bombing campaign. Unable to consistently replace aircraft damaged from combat and bombing, the Japanese would resort to using air-to-air phosphorus bombs to break up the bomber formations and destroy more bombers.

Japanese aircraft, mostly Mitsubishi A6M5 Zeros, would position themselves above the B-24 formations and release their phosphorus bombs which would explode over the formations sending phosphorus bomblets in a 300 yard wide pattern down onto the path of the bombers. Each 32 kg bomb would hold 75 steel encased phosphorus bomblets.

While very unsettling for bomber crews, the phosphorus air to air bombs were largely ineffective. More 7th Air Force B-24s were lost to ordinary flak than to phosphorus bombs.