Kansas City, Mo. ? 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.

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, based in Overland Park, Kan., sells propane under the Blue Rhino brand.