Two miners were killed in Colorado early yesterday, and authorities say they died of carbon monoxide poisoning, the Denver Post reports. The incident at the Revenue-Virginius Mine, near the town of Ouray, was described as a "powder-smoke incident" and was not a cave-in or collapse, the Ouray Watch reports. Twenty other miners went to area hospitals, but they all made it out of the mine on their own and most have been treated and released, the AP reports.
Investigators are looking for the source of the carbon monoxide, including the possibility that a small explosion on Saturday is to blame. A rep for mine operator Star Mine says all miners are required to wear personal respirators; the two victims had respirators and "as far as we can tell it doesn't appear to be an equipment malfunction," he says. The mine is closed for the duration of the investigation.