The problem surfaced as oil companies switch from MTBE to ethanol as an anti-smog additive. Similar problems caused supply problems on the U.S. East Coast last week.
Because ethanol-based reformulated gasoline is easily contaminated by water, the gasoline and ethanol must be sent separately to distribution terminals (like the facility shown at right) and mixed at the terminal before being trucked to gas stations. MTBE-based gasoline was sent to the terminal via pipeline, ready for distribution. Getting the ethanol to the terminals has proven to be more of a challenge than expected.