BISMARCK, N.D. (AP) — North Dakota regulators won’t order a company to stop work on an oil refinery near Theodore Roosevelt National Park so they can study the appropriateness of the site.

Meridian Energy Group last spring got state Health Department permission to construct the $800 million Davis Refinery 3 miles (5 kilometers) from the park. Ground work started in July.

Environmental groups who fear pollution in the park challenged the site with the Public Service Commission.

An administrative law judge recently said the PSC doesn’t have jurisdiction over the site because the refinery will be too small to warrant review under state law. The three-member commission voted Wednesday to dismiss the complaint.

Meridian still faces a legal challenge of its state air quality permit, and it still needs state water and wastewater permits.