ST. PAUL, Minn. (AP) — Minnesota utility regulators have decided pipelines that carry carbon dioxide are hazardous and therefore subject to state approval.

The decision by the Public Utilities Commission Thursday affects two multibillion-dollar CO2 pipelines proposed to cross Minnesota and carry waste from several ethanol plants in the Midwest.

Commissioners interpreted a 1998 state law on pipelines that carry hazardous materials includes those transporting carbon dioxide.

The decision initiates a rulemaking process that could take a year to complete. Actual approval of any CO2 pipeline could take months after that.

The companies seeking to build the pipelines disagree with the commission’s decision.