Complex sentence: His promising career ended abruptly after a crash in the 1964 Indianapolis 500 in which he was one of two drivers killed in a fiery inferno that directly led to a change in fuel type from gasoline to methanol.
Split into simpler sentences: His promising career ended abruptly after a crash in the 1964 Indianapolis 500. He was one of two drivers killed in a fiery inferno that directly led to a change in fuel type from gasoline to methanol.