Gail Norton, Secretary of Interior, is resigning

Washington - Gale Norton is expected to announce her resignation today after serving more than five years as secretary of the Interior pursuing an expansively pro-development agenda in the West, sources said.

Norton's top spokespeople did not immediately return phone calls seeking comment.

The former Colorado attorney general would be leaving without achieving her highest-profile political goal, opening the Arctic National Wildlife Refuge in Alaska to drilling.

Norton, who was the first female Interior secretary, has served since the earliest days of the Bush administration. Her background working for logging and mining interests made her one of Bush's most controversial cabinet nominees.

Under her watch, the department stripped protection from areas previously managed as wilderness, opened up forests to increased logging, reopened Yellowstone to snowmobiles and pressed federal land managers to speed up drilling for gas on public lands.

While natural gas supplies increased, environmentalists charged that the environment suffered.

Norton, however, stressed that she was working toward "cooperative conservation," a way to achieve environmental results by partnering with landowners and developers rather than regulating them.

Norton's tenure was also marked by ethical controversies. Several people close to her have been caught up in the scandal surrounding disgraced lobbyist Jack Abramoff, who lobbied her department on Indian casinos.

In the National Journal Political Insider's Poll last year, she was voted the second-most underrated Bush cabinet secretary by Republican operatives who credited her with pursuing Bush's pro-development agenda with a minimum of bad publicity.