From US News:
CLARKSVILLE, Tenn. — Three men and two women at a biker festival to raise money for needy children died in a recreational vehicle when fumes from a generator leaked into the camper, an organizer for the event said.
Police were investigating the deaths but said no foul play was suspected. Two of the men worked security into the early morning hours Sunday during the festival's party, which featured motorcycle drag races, live music and bikini and tattoo contests. The charity's website said there was free beer.
Bill Langford, the director of the event Bikers Who Care, was puzzled over the deaths at the Clarksville Speedway.
"Most of them didn't get to bed until four o'clock in the morning, and most of those people didn't go in that trailer at the same time to go to bed," he said. "I just find that kind that of strange. Why didn't they notice?"
It appears a small storage hatch on the RV did not close properly, allowing fumes from the generator to leak inside the vehicle, Langford said.
The gases were so bad in the camper that the bikers who found the bodies were taken to a hospital after feeling dizzy and light-headed, Langford said. They all had high amounts of carbon monoxide in their systems, he said.
Langford said the bikers' group was like a family and he was close friends with the people who had died. He identified them as a married couple, another couple and one of the men's co-workers.