Plaintiffs in a multi-state class action lawsuit allege that various gasoline and diesel fuel retailers, including Valero Marketing and Supply, BP Products North America, Inc., Shell Oil Products US, and ExxonMobil, sell fuel for a specified price per gallon without disclosing or adjusting for temperature expansion. As a liquid, gasoline expands and contracts depending on temperature. The volume of fuel is pegged to a 60-degree standard, at which the 231-cubic-inch American gallon puts out a certain amount of energy, but every degree over the 60-degree standard diminishes the energy output per gallon. According to the plaintiffs, a consumer who buys a gallon of fuel at a warmer temperature unknowingly receives less fuel (fewer molecules and less mass) than a consumer who purchases a gallon of that same fuel at a cooler temperature. The plaintiffs claim this allows the fuel retailers to pocket billions of dollars in excessive “temperature-inflated profits” each year. In 2012, the parties reached a settlement in which BP, ExxonMobil, and Shell agreed to pay $5 million and Valero agreed to pay $4 million.