Starting in 1965, USAC Indy Car competitions, including the Indianapolis 500, encouraged and later mandated the use of methanol fuel. Why? Because in the 1964 Indianapolis 500, there was a seven-car crash on the second lap. Two drivers died when their gasoline-fueled cars exploded. This fire created a cloud of thick black smoke that completely blocked the view of any oncoming cars, making the collision even more dangerous.
Enter methanol fuel. Methanol fires are essentially invisible in daylight; the flames are colorless and the combustion is smokeless. This means it can make racing accidents safer. However, invisible fire can be extraordinarily dangerous.
In the 1981 Indy 500, Rick Mears pitted on lap 58. During refueling, methanol fuel gushed out of the refueling hose before it was connected to the car. Fuel sprayed the car, as well as Mears and his pit crew, and then ignited upon contacting the engine. Mears and his pit crew were burning alive, but the fire was invisible.
Mears and four of his mechanics went to the hospital. No one was seriously hurt, although Mears underwent plastic surgery on his face. In response, Indy car fuel nozzles were redesigned with the addition of a safety valve that would only open when the nozzle was connected to the car.