An environmental group is taking its battle against an oil refinery being developed near Theodore Roosevelt National Park to the North Dakota Supreme Court.

The National Parks Conservation Association argued in its Wednesday filing that an air quality permit issued by the state Health Department for the $800 million Davis Refinery and upheld by a state judge violates the federal Clean Air Act.

The Health Department after a two-year review determined the refinery will not be a major source of pollution that will negatively impact the park just 3 miles (5 kilometers) away. The permit the agency issued in June 2018 cleared the way for construction to begin. Meridian Energy Group began site work last summer and plans to resume construction this spring with a goal of having the refinery fully operational by mid-2021.

State District Judge Dann Greenwood ruled in January that the Health Department had effectively supported its position. Greenwood refused to declare the permit invalid and send the case back to the agency for a more rigorous review. The NPCA wants the Supreme Court to overrule him.

"Although the underlying permit contains a requirement for the Davis Refinery to keep monthly logs of its actual emissions ... the permit contains no requirement that the Davis Refinery install monitors to actually collect this data," association attorney Derrick Braaten said.

The group fears that pollution from the refinery will mar the park's scenery and erode air quality for wildlife and visitors. The park is North Dakota's top tourist attraction, drawing more than 700,000 people annually.

"With the decision to appeal, NPCA is fighting to protect the park that has inspired generations of conservationists," Stephanie Kodish, clean air program director for the association, said in a statement.

Roosevelt ranched in the region in the 1880s and is still revered by many for his advocacy of land and wildlife conservation.

Meridian maintains the facility will be "the cleanest refinery on the planet" thanks to modern technology and will be a model for future refineries. The company in a statement Wednesday said it does not comment on pending litigation.

State Air Quality Director Terry O'Clair said he had not had a chance to review the appeal but that "we're confident in the permit that was issued."

Meridian in late January obtained a needed state water permit . It still faces a separate state court battle related to the refinery's location. Two other environmental groups are challenging a decision by North Dakota regulators who concluded they were barred by state law from wading into the dispute over the site.