The US Court of Appeals for the Tenth Circuit remanded Colorado’s air quality plan back to the Environmental Protection Agency (EPA) Monday because it failed to account for emissions from drilling, fracking and well completion.

Colorado must submit permits that align with national air quality standards, which include regulations for stationary sources that emit pollutants. A stationary source in this context includes drilling, fracking and well completion.

The Tenth Circuit stated that the EPA incorrectly assumed the provision about stationary source was not substantive and therefore the EPA did not independently evaluate it. However, the Center for Biological Diversity contends that the new provision pertains to “pollutants emitted before a well starts producing,” which creates a new type of pollutants within Colorado’s air quality plan.

Colorado stated that “the revised definition hadn’t changed the method of calculating potential emissions.” However, the court still rejected this argument as the provision needed to be independently evaluated. The court found that the EPA acted “arbitrarily and capriciously” under the Administrative Procedure Act, and therefore the decision was rendered unlawful and needed to be remanded to the EPA.

The Tenth Circuit stated that the Center for Biological Diversity “generally supported” the updating of Colorado’s implementation plan, but that it was not taking any “position on the specific provisions.” The Center states that it did not waive any objections to the rule-making process that would allow for implementation of the policies on stationary sources. The Tenth Circuit further rejected Colorado’s position that a party who makes an error is barred from having it set aside on appeal because the “error must be clear from the record”. The Court stated that the error in this case was not clear from the record.

In March, the EPA announced significant deregulation to abide by President Donald Trump’s promise to “give power back to the states.” On April 24, the US Supreme Court heard oral arguments in a California fuel emissions case.