The U.S. Forest Service (search) will propose regulations to shorten the environmental reviews of small oil-drilling projects in national grasslands, an Agriculture Department official said Friday.

The proposal would affect grasslands covering about 4 million acres in a dozen states in the Great Plains and West.

Oil exploration is off limits in some areas of the national grasslands, but where drilling is allowed, a required environmental assessment takes a minimum of six months. North Dakota Gov. John Hoeven (search) complained some of the reviews were taking three times that long, delaying projects that could help the economy.

Mark Rey, a USDA undersecretary, outlined a proposal Friday to allow some small projects to undergo two-month reviews instead.

The projects eligible for the shorter reviews could not include more than three miles of pipeline or more than four drilling rigs, he said.

An advocate for the environment was wary of the proposed rules.

"I want to see the specifics, but this at first blush looks like another attempt to accelerate oil and gas development in the Badlands without taking the necessary steps to protect the environment," said Wayde Schafer, a Sierra Club (search) conservation organizer.

Hoeven argued that the process could be streamlined without harming the environment.

"This has been a big thing for industry, and it comes at the right time," the governor said. "It comes at a time where we recognize we need to increase domestic (oil) supply."

Besides North Dakota, states with national grasslands are California, Colorado, Idaho, Kansas, Nebraska, New Mexico, Oklahoma, Oregon, South Dakota, Texas and Wyoming.

The proposed regulations are to be published in the Federal Register (search) in a few weeks. That will mark the beginning of a 60-day period during which the Forest Service will take comments on the proposed rules.