It may look like nothing’s happening, but that’s exactly why it’s so dangerous.

At the 1981 Indy 500, observers got a frightening science lesson when driver Rick Mears exited from his car in a panic.

See, during a pit stop, methanol, the fuel used by the vehicles, was accidentally sprayed across Mears’ car, the pit crew and the surrounding area. The flammable liquid ignited, with some of the flames reaching the cockpit and engulfing his helmet and suit.

However, methanol fire is invisible to the human eye, and so, for anyone who didn’t understand what was happening, it was a truly bizarre and scary sight. Thankfully, Mears was okay and had a long career afterwards, and safety regulations were adjusted to lower the likelihood of this happening again.