The debate over 'hot fuel' is being waged on the Internet, in newspapers, in Congress, and now its also making its way into the courtroom.

Hundreds of consumers, truck drivers and others in more than a dozen states are suing oil companies and fuel retailers, alleging they have been overcharging fuel buyers by billions of dollars.

The suits contend that higher temperatures of gasoline and diesel fuel cost consumers and commercial vehicle operators between 3 and 9 cents a gallon extra at the pump.

The litigation seeks to force the oil industry to install gas pumps that have temperature-compensation equipment.

The lawsuits are known to have been filed in California, Delaware, New Jersey, Kansas, Oklahoma, Missouri, Louisiana, New Mexico, Nevada, Florida, Kentucky, Tennessee and Georgia.

Dan Gilligan, president of the Petroleum Marketers Association of America, predicts the suits will fail because they allege fraud, which he says has not occurred.

He also disputes the billion-dollar estimates of costs to consumers.

'There is so much misinformation put out by people doing guesses,' he told one national publication. 'They have no idea what the temperature at the nozzle is. We need facts, not hype.'

The legal battle centers on century-old oil industry fuel pricing practices and competing scientific and mathematical testimony from experts on both sides. The price of gasoline has been based since the 1920s on a formula that measures a gallon of gas when it is 60 degrees, say several of the suits.

According to industry and government standards, a gallon of gas at 60 degrees measures 231 cubic inches. Consumers buy 231 cubic inches of gas per gallon, regardless of its temperature, so when gas expands in the heat, the amount of energy put out per gallon declines.

The industry routinely makes price adjustments for temperature fluctuations for wholesalers, but not consumers, according to the court filings.

Many of the suits were consolidated early this summer in federal court in Kansas and assigned to U.S. District Judge Kathryn Vratil, who will oversee preliminary hearings. More than 100 defendants are named in the lawsuits, ranging from oil industry giants such as ExxonMobil and Chevron, to retailers including Wal-Mart, QuikTrip and 7-Eleven.

The plaintiffs include hundreds of motorists, plus long-haul truckers and other commercial driver groups.

Gilligan says the cost of installing temperature-adjustment equipment would be prohibitive. NATSO, a trade group that represents truck stop operators, has estimated the cost of equipping each pump at between $1,500 and $3,800.

It's our view, generally speaking, that most Americans are made whole in the course of a year,' Gilligan says. 'They lose BTUs in the summer, but gain them back in the winter.'

However, the consumers' attorneys say that in Canada - where gas temperatures are generally colder, and the advantage shifts to the consumer - temperature-adjustment equipment already has been installed at the gas pump.

George Zelk, a Chicago attorney representing truck drivers in several states, says the oil industry wants it both ways.

'The industry has pushed for this temperature adjustment in Canada, where they lose money, where it's colder than 60 degrees, and opposed it in the United States where it's warmer than 60 degrees,' he says.