CHEYENNE, Wyo. (AP) -- New rules against burning off excess natural gas from oil and gas wells on public land are taking effect after a federal judge refused to block them pending the outcome of a lawsuit.

U.S. District Judge Scott Skavdahl in Casper ruled Monday he can't immediately conclude the Interior Department oversteps its authority with the rules requiring gas to be captured rather than flared.

The rules seek to reduce air pollution and gas waste. They took effect Tuesday but Skavdahl points out certain provisions aren't effective for another year.

Montana, Wyoming, North Dakota and two petroleum-industry groups wanted the rules blocked immediately, saying in a lawsuit they exceed Interior's proper authority.

Environmentalists praised the decision while the Western Energy Alliance says it's confident the states and industry will prevail in court.