Cooking kills. At least, it does if you use a leaky, inefficient stove or an open fire to cook your meal.
Cooking-related indoor air pollution kills more people than do cigarettes, according to this ITDG (the Intermediate Technology Development Group) report.
They're not glamorous tech, but better stoves are one of the most needed tools on the planet. Existing designs and existing programs for encouraging people to adopt new stoves both fall short. But we're learning how to build better programs.