KANSAS CITY, Mo. (AP) – The heat is being turned up on big propane companies who last summer quietly reduced the amount of fuel in canisters that are attached to backyard grills without telling their customers, according to a pair of federal lawsuits.

The propane companies named in the suits said they cut the amount of fuel in each tank to avoid raising prices last summer when energy prices soared. Propane prices have since plunged, however, yet the practice of putting 15 pounds of gas in a 20-pound tank continues.

Attorneys, who are seeking class-action status in both suits, say the companies failed to give fair warning to customers.

“When you’re paying more for less it affects people in the long run and it affects their pocketbooks,” said Eric Gibbs, an attorney representing a California man in a case filed against FerrellGas on June 4 in the U.S. District of Kansas.

Gibbs’ client noticed there was less fuel when he lifted the tank at home, he said.

The second case, filed on June 9 in the U.S. District of Northern California, involves four plaintiffs who are suing FerrellGas and AmeriGas.

FerrellGas sells propane under the Blue Rhino brand.

That suit accuses the two companies of violating consumer protection laws in 36 states and the District of Columbia.

“The case is about customers being told they were receiving a full tank when they weren’t, and these companies’ nondisclosures that they were short-filling the tanks,” said attorney Dan Kurowski.

The industry has typically sold 20-pound tanks with 17 to 18 pounds worth of fuel, the shortage allowing the gas to safely expand when heated.

In a statement, Valley Forge, Penn.-based AmeriGas called the legal claims “misguided,” saying it changed the labels on its tanks to reflect the lower amount of fuel.

The company, however, said it was “very concerned to learn that some consumers may feel they were not adequately informed and we’re committed to taking additional steps if needed to protect their trust and confidence in us.”

When asked what those additional steps might be, company spokesman Bill Katz said the company hoped “to have something to announce in the next couple of weeks.”

Spokesmen for Overland Park, Kan.-based FerrellGas didn’t immediately return phone calls.