Flammable gas emitted by sausage While cooking a kielbasa in a toaster oven today, I noticed that periodically there would be flashes near the heating element. At one point there was a very large, bright flash of light and pop as though a flammable gas was being detonated. Some of the ignitions I was able to see in detail. Next to the heating element a small round flame would illuminate and waver then go out. It was obvious that some lighter than air gas was rising up and upon reaching a high enough concentration, igniting.

What gas would the kielbasa be emitting? My first guess would be methane, but why would a cooked kielbasa be giving off methane?
Cured meat should not be emitting methane- or any other flammable gas. That would be an indicator of advanced spoilage and you would notice the smell.

A more likely culprit, in my opinion, would be fat.

Fat burns well, of course, and sausage is full of it. Tiny splatters of fat can become aerosolized and travel a good distance where they would ignite on the burner.