The death of Hickman High School math teacher Dennis Dallman has been ruled accidental following a preliminary investigation by the Boone County Sheriff’s Department.
An autopsy conducted Thursday found “classic examples of carbon monoxide poisoning during the examination,” said Sgt. Tom Reddin of the sheriff’s department. The investigation won’t be completed until toxicology and other laboratory analysis are completed in a few weeks, Reddin said.
Sheriff’s deputies found Dallman, 56, Wednesday morning on the living room floor of his house on Ridgewood Road. The television was on and Dallman’s car was parked in the garage with the engine running. Reddin said the investigators learned that it was normal for Dallman to watch TV while lying on the floor.
Deputies found nonperishable groceries in Dallman’s car, leading them to believe he came home, took in the perishable groceries, and he either decided to bring the rest in later or he forgot about them, Reddin said. Also found was a receipt from Gerbes groceries, with a time stamp of 7:30 p.m. Tuesday.
“We do so many things automatically every day, that there are times when, for whatever reason, we may think we have done it, because we always do,” Reddin said. “But we didn’t.”
Reddin said Dallman was hard of hearing, and probably wouldn’t have heard the car running in the garage. The fact that Dallman had to turn up the volume of the TV to hear it only compounded the problem.
“There was no indication anywhere in this investigation that foul play existed, that someone else had possibly caused harm to Mr. Dallman, or that he had harmed himself,” Reddin said.
Reddin said the evidence was “out of character” for a suicide because Dallman had not done anything to facilitate his death, such as staying in the car and sealing off the garage.
“None of that existed in this case,” he said.
This was the second fatal incident involving accidental carbon monoxide poisoning in Columbia in recent months. Two women and a 10-year-old girl were found dead March 10 in their Primrose Drive home after a car was left running in the garage underneath the house. Reddin said he didn’t believe this was indicative of a larger problem.
“Two incidents don’t mean a trend,” he said.