U.S. Interior Secretary Ken Salazar says he's scrapping leases on federal land for oil-shale development in Colorado, Utah and Wyoming.

Salazar's action on Wednesday marks the second time he has reversed an action by the Bush administration. He also halted the leasing of oil and gas drilling parcels near national parks in Utah three weeks ago.

Then as now, Salazar says he is reversing a "midnight decision" by the former administration.

Salazar is rescinding a low royalty rate along with a Jan. 14 lease offer on millions of acres in the three states. He says he'll consider making some of the land available later for new research projects.

The federal government already has leased land in Colorado and Utah -- but none in Wyoming -- for small-scale oil-shale works.