Mass is perhaps best known for his blameless part in the death of Gilles Villeneuve. On 8 May 1982, with only 10 minutes left until the end of the qualifying session for the 1982 Belgian Grand Prix at Zolder, Villeneuve collided with Mass while attempting to overtake him. As Villeneuve came up behind Mass exiting a super-fast left turn, Mass moved to the right hand side of the track to let Villeneuve through. Villeneuve had already committed to the right hand side and the two cars touched wheels, launching the helpless Canadian skyward. Villeneuve's car hit the ground nose-first and was then torn apart in a series of violent cartwheels. His seat was dislodged and he was flung from his car, landing heavily among the catch fencing at the opposite side of the track. Mass stopped his car, jumped out and ran back to Villeneuve's wrecked car, but there was nothing he could have done. Villeneuve was flown to hospital and taken off life-support later that evening.