The Franklin County Sheriff's Office was investigating a death Wednesday that appeared to have been caused by carbon monoxide poisoning.

Kenneth Witten, 41, was found unresponsive Tuesday evening in an outbuilding where he had been staying, sheriff Pat Melton said. The building was behind a trailer in rural, northern Franklin County near the Henry County line.

Detectives found a propane heater inside. The gas valve had been turned on, but the flame was not lit.

Emergency medical technicians rushed Witten to Frankfort Regional Medical Center, but it was too late to save him, Melton said. He was pronounced dead at the hospital.

An official cause of death had not been determined Wednesday, but preliminary information pointed to carbon monoxide poisoning, Melton said.

If so, Witten's death will be the first carbon monoxide death that Melton has investigated "in many, many years of law enforcement," he said.

"You hear about it happening all the time, but it always happens somewhere else," he said.

Melton reminded residents to take precautions against carbon monoxide, a colorless, odorless, tasteless gas that can be emitted by gas-powered machines and by water heaters, stoves and cars.

"Obviously at this time of year, hunters are going out, people are turning on their heaters," he said. "Before you do that, you really need to check your carbon monoxide detectors and make sure the batteries are new and they are working properly."

Witten's death "is a very tragic reminder of that," he said.

Josh Kegley: (859) 231-3197. Twitter: @HLpublicsafety.