WASHINGTON -- Contractors working on hurricane recovery have overbilled the government in a $63 billion operation that only will get more expensive, according to a House report Thursday.

Mileage claims were overstated to get more fees, debris was mixed improperly to inflate prices and companies sent bills twice for removing the same loads, Democrats on the GOP-controlled House Government Reform Committee found.

In a Thursday hearing on the government's contracting procedures after Hurricane Katrina, AshBritt Inc. of Pompano Beach was among several companies whose representatives explained how their government contracts worked.

Rep. Henry Waxman, D-Calif., who compiled the report, complained about layers of subcontractors that drove up costs.

A major contractor would take a large cut and pay smaller amounts to the subcontractors, down to the company with the truck hauling debris to the dump.

Randall Perkins, president of Ashbritt Inc. said his company received $23 a cubic yard in a debris removal contract but paid a subcontractor $10 to haul the material.

"It seems you get more than half," Waxman told Perkins. "We outsource to companies like yours, and they go out and subcontract. It's a higher overhead."

Perkins said some cleanup contractors hired many subcontractors, but he hired only a few. He said the prices he charged were determined partially by U.S. Army Corps of Engineers rules he had to follow.

The committee chairman, Rep. Tom Davis, R-Va., said Congress approved more than $63 billion for disaster relief and that recovery expenses may top $200 billion.

Davis said many contracts were awarded without competition.

Government officials at the hearing said these contracts were being replaced with competitive awards.

Davis said the sole-source contracts allowed an "unprecedented opportunity for fraud and mismanagement."