The question most pilots are asking, of course, is what will we pay to fill our tanks with approved unleaded aviation gasoline? The UAT ARC report authors admitted they don’t have an answer. Instead, they pose another question, which should be even more worrying to the GA community: There is currently only one supplier of the tetraethyl lead (TEL) used in avgas. What if that supplier, a company called Innospec, sees the handwriting on the wall and suddenly decides to exit the market? The report’s authors predict it would lead to hoarding of TEL and skyrocketing prices for 100LL.