A crude oil storage tank exploded as two teens were jumping on it, hurling the youths 150 yards to their deaths, deputies said Monday.
The tank exploded Saturday night during a party in Routt National Forest, about 135 miles west of Denver, Rio Blanco County Undersheriff Michael Joos said.
Vapor from the 160 barrels of crude oil in the tank may have been forced out through a relief valve by the pressure of the teens jumping on the top, Joos said.
He said deputies were trying to determine whether a campfire or a cigarette lighter ignited the vapor. Some of the 18 people at the party had lit a campfire, Joos said, but he was not sure how close it was to the tank.
A dog also was killed, but no other injuries were reported, Joos said.
The Colorado Bureau of Investigation was investigating.
The victims were identified as Samuel Hedemark, 17, of Phippsburg, and Christopher King Fuller, 19, of Yampa.
Coroner Randall Cochran said marijuana was found in both teens' bodies and each had a blood-alcohol level higher than the 0.08 percent legal limit for driving.