Authorities are trying to determine exactly what sort of accident occurred in a mine in southwestern Colorado that left two miners dead of carbon monoxide poisoning and injured 20 others.
The Ouray County sheriff's office was called to the Revenue-Virginius mine at 7:20 a.m. Sunday.
Ouray County spokeswoman Marti Whitmore said the miners were underground and were confirmed dead Sunday afternoon. Authorities said at a late night news conference that the two died from carbon monoxide poisoning.
Local media were reporting that investigators are looking at whether a blast on Saturday played a role.
Two newspapers identified the dead as 34-year-old Nick Cappanno of Montrose, Colo., and 59-year-old Rick Williams of Durango, Colo.
The 20 injured were taken to three area hospitals, and most were treated and released.