While the circuit's natural setting created conditions for a sinuous, challenging race course, it also created safety concerns due to the dark, volcanic rocks which fell from the mountain onto both sides of the track. The rocks meant that tire punctures were a perennial hazard at the Charade Circuit, as was shown when 10 competitors suffered punctures during the 1972 French Grand Prix. Drivers who skirted the track edge would send rocks flying in the middle of the road and into the path of pursuing competitors. In the most serious incident at the 1972 French Grand Prix, a stone thrown from Emerson Fittipaldi's Lotus penetrated the helmet visor of Helmut Marko, blinding him in the left eye and ending his racing career. The mountainous topography also left no room to provide safe run-off areas in the event of competitors losing control of their vehicles and unintentionally leaving the race course.