Clip transcript:

Did you know that premium gasoline was once called "ethyl?" Who was Ethel, and why was a gasoline named after her? Well, ethyl was short for "tetraethyllead" a chemical that helped gasoline burn properly in high compression engines. But the lead also went out the engine's exhaust pipe, contaminating the air and ground. And contaminating catalytic converters designed to remove other exhaust pollutants. So lead, and Ethel, disappeared from our gasoline by 1996.