Some Alaska politicians said Friday they are outraged by the U.S. Army Corps of Engineers' decision to deny Conoco Phillips a permit that would have given it access to drilling in the National Petroleum Reserve-Alaska.

"That's a half a billion dollars of development lost," said Rep. Craig Johnson, R-Alaska, who chairs the House Resources Committee.

Conoco and Anadarko Petroleum had sought permission from the Corps to build a bridge over the Colville River to explore what would have been the first oil and gas lease in the reserve.

The Corps said Friday that the company's proposal did not comply with Clean Water Act rules that prevent filling in wetlands if there is another feasible way to do the project that creates less environmental harm.

Other alternatives for accessing the oil and gas include directional drilling, and that will require new permit applications, the Corps said.

Directional drilling would "minimize impacts to the Colville River Delta, which is the largest and most complex delta on the Arctic Coastal Plain and drains nearly 30 percent of the North Slope," the Corps said in a press release.

The Corps said the delta provides habitat for about 80 bird species, migrating caribou and nearly 70 percent of the overwintering fish on the Slope. The delta is also used for subsistence hunting and fishing by Nuiqsut residents.