LOS ANGELES -- A class-action lawsuit filed last week accuses 17 oil companies and gasoline-service stations of not compensating for changes in gasoline volumes when temperatures rise, The New York Times reports. Companies named in the suit include Chevron, 7-Eleven, Valero and Wal-Mart Stores.

The suit contends that customers are overcharged for gasoline during warm weather because gasoline expands when the temperature exceeds 60 degrees. The suit, brought by a small number of truck drivers and motorists in California, alleges that consumers receive less energy for each gallon purchased.

According to the Ralph Nader-founded group Public Citizen, the oil industry does not want to install equipment to adjust gasoline volumes delivered at the pump when temperatures change. Public Citizen claims that the temperature differential costs consumers more than $2 billion a year, the newspaper reports.

However, American Petroleum Institute spokesperson John Bisney told Reuters, “When you buy a gallon of gas, you buy a gallon of gas. Sometimes you get a little more, sometimes you get a little less.”

Bisney added that the cost of installing any equipment to cool the fuel would negate any benefits to consumers in terms of greater mileage, he told Reuters.

NACS and a number of other associations have stressed that mandating temperature compensation would be costly, confuse the market and most directly impact small-business owners that make up the overwhelming majority of petroleum retailers I nthe country.

The December 2006 issue of NACS Magazine provides more perspective on the issue of “hot gas.”