 Hassler died of injuries sustained as a result of a 13 car-pileup during the first qualifying race of the 1972 Daytona 500 at the age of 36 and at the peak of his career.It happened on lap 19 when the No.57 Dodge of David Ray Boggs blew his right rear tire.Hassler, caught in the pileup, spun his No.39 Chevy into the infield grass before careening back into the track and slammed into the outside wall head-on.