Two people were killed due to carbon monoxide poisoning and twenty others were injured in a mine in Ouray, Colorado on Sunday.
The incident occurred early Sunday morning at about 7 a.m. a what officials confirmed as the Revenue-Virginius mine in Ouray, which mines silver, lead, zinc, copper and gold, reports NBC News.
All of the 20 injured were able to get out of the mine safely, but a rescue crew later found two bodies at about 3 p.m. local time.
The two miners who died were trapped about 8,000 feet below the surface in the mine and their fellow miners could not get to them in time, according to the Daily Sentinel.
The men who work in the mines are required to wear respirators. The miners who died Sunday were reported to have been wearing theirs at the time of the incident as they had all been alerted to a gas buildup.
An intentional blast was caused on Saturday, which is a technique frequently used in mines to reach mine ores, is believed to have been a possible cause for the gas buildup within the mine, reports the Sentinel.
The miners who were killed Sunday have been identified as 34-year-old Nick Cappano and 59-year-old Rick Williams.
"I knew both of these individuals personally," said Rory Williams, the manager of operations for Star Mine LLC, reports The Denver Post. "They were hard-working men. They were great men. They will be remembered indeed."
20 other miners were sent to various nearby hospitals following Sunday’s incident where four were admitted and reported to be in fair condition, while the other 16 were released sometime Sunday afternoon.
Williams said that accidents like this do not happen often.