SOMERSET, Colo. (KKCO) – The Elk Creek Mine has been temporarily closed as investigators look into the cause of dangerously high carbon monoxide levels.

The poisonous gas was detected Tuesday night, according to Jim Cooper, the president of Oxbow Mining, LLC.

All workers evacuated Wednesday morning, and the Mine Safety and Health Administration (MSHA) arrived on scene to investigate the cause.

Cooper says the mining company drafted a plan Wednesday to ventilate the area and clear the threat, but that plan needs to be approved by MSHA officials before operations can restart.

He does not have an exact timeline for when the mine will be reopened.

KKCO 11 News will bring you more details as they become available.