Washington ? While removing enough debris to cover Britain, contractors working on hurricane recovery have overbilled the government in a $63 billion operation that will only get more expensive, according to a House report Thursday.

Mileage claims were overstated to get extra 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.

Rep. Henry Waxman, D-Calif., who compiled the report for the hearing on Katrina contracting, also complained about layers of subcontractors that drove up costs.

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.