The National Wildlife Federation and Colorado Wildlife Federation filed a challenge with the state's Bureau of Land Management over plans to offer 2,200 acres for auction May 9. Colorado Wildlife Federation Executive Director Suzanne O'Neill said BLM State Director Helen Hankins needs to take environmental concerns seriously.
Both groups said that withdrawing the leases would ensure that "any future development that occurs is the result of a thoughtful, collaborative plan that balances energy development with other multiples uses, including hunting and its significant economic contribution, and the needs of the community."
The groups said the lease area includes habitat for grouse and deer species. Plans for the lease are nearly 30 years old.
The U.S. Energy Department said Colorado has an estimated 386 million barrels of proven oil reserves. State oil production accounts for around 1 percent of overall U.S. production.
Shale development company Nighthawk last week reported that the oil reserve potential at the Smoky Hill project in the state could be as high as 14.5 million barrels.
There was no public comment from Colorado's BLM.