WASHINGTON (AP) -House Republicans attacked a Democratic offshore drilling plan Friday for including a 50-mile coastal buffer that they said would leave untouched most of the 18 billion barrels of oil in waters now off-limits to energy companies.

A Democratic drilling proposal expected to be taken up by the House next week would allow energy development access to waters 50 to 100 miles from shore along almost all of the country’s coastlines as long as a state agrees to drilling off its shore.

Waters off Florida’s Gulf coast and a nationwide 50-mile coastal buffer would remain out of bounds to energy companies.

But House Republican Leader John Boehner called the plan a “hoax on the American people,” arguing that nearly 90 percent of the oil believed to be in the restricted offshore waters still would not be available.

House Republicans have called for lifting the offshore drilling bans everywhere with no protected buffer.

“Keep in mind, we’re opening up millions of more acres (to drilling) at a time when the industry claims they don’t have the drills to explore the resources they have,” said Drew Hammill, a spokesman for House Speaker Nancy Pelosi.

While drilling between 50 to 100 miles from shore would require state approval, areas beyond 100 miles where drilling also is banned would be opened without such restrictions under the Democrats’ plan.

The Interior Department estimates that waters now under drilling bans off the Pacific and Atlantic coasts and in the eastern Gulf of Mexico contain nearly 18 billion barrels of recoverable crude oil with more than half that found off California.

Meanwhile, two reports released this week by the Government Accountability Office described shortcomings in the Interior Department’s collection of royalties from the oil and gas pumped from federal waters where drilling already is permitted.

One report cited a 2007 investigation that found the money the U.S. government receives in royalties from oil and gas taken under federal leases is much less percentage-wise than what most other countries collect from their oil and gas extraction.

Another report cited the department’s long-standing problems with how it audits the royalty collection program, saying at times the Interior Department doesn’t have an accurate accounting of how much oil and gas is being taken and how much money is due the government.

Most of these concerns have been raised before in various GAO and other reports. But they were given fresh exposure as lawmakers debated offshore drilling and a day after the release of a devastating Interior inspector general’s report described conflicts of interest, drug and alcohol abuse and promiscuity in a federal office involved in the royalty program.

The Democrats’ drilling proposal is part of a broader energy package – including taxes on oil companies and new tax breaks and other measures to spur development of renewable energy programs -that is scheduled to be taken up next week in the House.

The Senate next week will consider at least three proposals that call for an expansion of offshore drilling – one being developed by Democrats, another by Republicans and a third by a bipartisan group. All are expected to have some expansion of offshore drilling.