Oil lease mistake costs government billions — It never ends. Both Democrats and Republicans are at fault.

WASHINGTON — Interior Department staffers knew back in 2000 they had bungled offshore lease agreements signed with oil companies operating in the Gulf of Mexico but covered up their multibillion-dollar mistake for six years, an investigator said today.

In a statement prepared for his appearance today before a House panel, Interior Department Inspector General Earl Devaney warned lawmakers the department responsible for collecting oil royalty payments on behalf of the federal government is rife with “managerial irresponsibility and a lack of accountability”

“Simply stated, short of a crime, anything goes at the highest levels of the Department of Interior,” Devaney said in the statement describing the general culture of the department.