KANSAS CITY, Mo. -- Big box giant Costco has agreed to change pumps in the hottest regions in the U.S. to compensate for the fact that fuel at higher temperatures offers consumers less energy for their dollar.

The Kansas City Star reports that the "precedent-setting plan ... which still needs court approval, also would end what had been unanimous opposition by the oil industry and retailers to selling U.S. consumers temperature-adjusted fuel."

Truckers and industry groups have been watching the so-called "hot fuel" issue for some time.

Like most liquids at hotter temperatures, fuel expands, reducing the energy content in tanks hotter than the century-old standard of 60 degrees. The hotter the fuel -- whether by radiant heat from the sun or from the refinery process -- the more drivers pay for less btu energy (and thereby less miles to the gallon).

Over the past few years several class action lawsuits have been launched against oil companies and fuel retailers for overcharging at the pump.

At the urging of the Owner-Operator Independent Drivers Association (which has a web site, www.turndownhotfuel.com, addressing the issue), a U.S. sub-committee began investigating allegations that oil companies are squeezing extra dollars from drivers.

There are devices that can be installed on retail pumps to make up the difference in price, called automatic temperature compensation retrofit kits.

The Star reports that Costco will change its gas pumps to make the adjustment in the warmest states where it has stores, including California, Texas and Florida. The wholesale fuel that Costco buys in those states is temperature-adjusted.

In other states, Costco stores would not make changes to their pumps where the company doesn't buy temperature-adjusted fuel at wholesale, and therefore isn't pocketing any profit in the difference caused by the temperature differential.

While Costco sells gasoline, not commercial diesel fuel, this settlement could set a precedent and prompt other retailers to do the same.

OOIDA has been challenging the National Conference on Weights and Measures to require fuel retailers in all 50 states to install temperature-compensation devices as a solution to this problem.

Some states have already begun the legislative process to try to put an end to retailers' practice of selling fuel warmer than 60 degrees.