Original: Any chance to return was erased in 1958 when motor racing was banned by the Swiss government as an unsafe spectator sport following the death of 80 people at the 1955 24 Hours of Le Mans race.
Simplified: In 1958, motor racing was banned by the Swiss government as an unsafe spectator sport. The was in reaction following the death of 80 people at the 1955 24 Hours of Le Mans race.