MANCHESTER, Tenn. (AP) — Four paramedics working at the Bonnaroo Music & Arts Festival have been hospitalized for possible carbon monoxide poisoning.

Coffee County Sheriff's Office spokesman Lucky Knott tells news outlets it appears the exhaust of a generator used to power the recreational vehicle they were staying in was blocked. One of the paramedics woke up Monday and was able to get help.

Three were airlifted to hospitals, while the fourth was taken to an area hospital. Their names and conditions haven't been released.

Knott says the paramedics are not employed by Coffee County's emergency medical services.

The sheriff's office says at least 37 Bonnaroo attendees had been hospitalized as of Monday morning. The festival recorded a fatality on its second day, when 32-year-old Michael Donivan Craddock Jr. was found dead in his car.