This legislation requires the Environmental Protection Agency (EPA) to finalize a specific proposed rule concerning E15 fuel dispenser labeling and underground storage tank (UST) compatibility within 90 days. The bill directs the EPA to adopt the first co-proposal for E15 labeling and establishes several key provisions for UST compatibility. It deems existing UST systems compliant with fuel blends up to 15 percent ethanol, even without documentation, and explicitly considers steel and fiberglass USTs manufactured after July 2005, along with all fiberglass piping, as compatible with E15. Owners can also demonstrate compatibility for individual components without replacing the entire system. To ensure future flexibility, the legislation mandates that any new or replaced components of UST systems storing motor fuel for on-road vehicles must be compatible with fuel blends containing up to 100 percent ethanol. This requirement applies regardless of the fuel currently stored in those systems. This proactive measure aims to prepare infrastructure for potential higher ethanol blends in the future.