The decision marks the third consecutive year the administration has lengthened the period during which Americans can keep buying E15, a gasoline that uses a 15% ethanol blend. Sales are effectively blocked from June 1 to Sept.
Adding ethanol to gasoline is known to increase smog pollution in hot weather, but research has shown little difference between E15 and the more-widely available E10 blends.
Also this just happened: https://www.reuters.com/business/energy/us-epa-allows-temporary-expansion-higher-ethanol-gasoline-blend-this-summer-2024-04-19/