A Colorado activist group this week filed a lawsuit challenging a state law that allows oil and gas companies to drill a property owner’s minerals without consent of the owner.

The move is the latest effort by environmental activists to tighten drilling regulations in the fifth largest oil-producing state in the U.S.

The complaint, filed by Colorado Rising on behalf of mineral owners in a Denver suburb, challenges the state's forced pooling rule, a decades-old law that was intended to help efficiently develop mineral resources.

Defendants in the complaint include the State of Colorado and the Colorado Oil and Gas Conservation Commission, which regulates the state's oil industry.

Under the law, an operator seeking to develop minerals on contiguous tracts of land can apply through the state's oil and gas regulator to access minerals on properties where owners may not want to lease their mineral rights.

Across Colorado, oil and gas operators requested to pool some 30,000 non-consenting mineral owners last year.

"Forced pooling is a perfect example of Colorado’s antiquated oil and gas laws that must be updated in accordance with modern technology," Anne Lee Foster of Colorado Rising said in a statement. She pointed to horizontal drilling, which helped spur a boom in U.S. shale production, but also allows operators to drill longer distances underground, impacting more landowners.

The Colorado Oil and Gas Association on Jan. 23 said pooling was essential for horizontal drilling and that the latest move by Colorado Rising was "all about shutting down energy production."

A representative for the Colorado Oil and Gas Conservation Commission declined to comment. The office of Governor Jared Polis did not immediately respond to request for comment.

Last year, Colorado voters struck down a measure that would have required a greater distance between new oil and gas development and public spaces. Opponents said the move would have hurt the state's oil and gas industry and economy.

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