Complex sentence: Additionally, some members of the crews of the B29 Superfortress bombers sent to drop atomic bombs on Japan were issued with lethal pills, though all aircraft returned safely and none of the pills were used.
Split into simpler sentences: Additionally, some members of the crews of the B29 Superfortress bombers sent to drop atomic bombs on Japan were issued with lethal pills. In the event all aircraft returned safely and none of the pills were used.