A lot of folks use AV gas for chainsaws as its ethanol free and tends to be shelf stable. Its also the only option for some folks who do not access to ethanol free gas. After decades of on/off attempts, its looks like lead free Av gas is now going to be available with no lead. https://www.flyingmag.com/g100ul-avgas-replacement-set-to-soon-hit-pumps/