ENFIELD – Investigators were awaiting toxicology reports Friday to determine whether an 86-year-old man died of propane gas poisoning.

Relatives who went to check on Harold Tozier of 19 Old County Road North found him lying face down in his living room at about 3 p.m. Thursday, said Trooper Joshua D’Angelo, who is investigating.

A propane gas stove was leaking into the air but wasn’t lighted. The gas odor was strong. The relatives immediately called 911, D’Angelo said. Firefighters from the Howland Volunteer Fire Department arrived and immediately ventilated the room.

The stove was not turned on, D’Angelo said Friday. Howland firefighters didn’t have a multigas detector to determine whether enough propane gas had leaked from the stove to kill Tozier, Howland Fire Chief Phil Dawson said.

According to the Web site for the Centers for Disease Control and Prevention, an Atlanta-based health monitoring organization, propane is a heavier-than-air, colorless gas that can cause flash fires or explosions when ignited or frost burns when it touches human skin. An odorant is added to make it detectable.

Even if not ignited, the gas can be deadly because it displaces air, Dawson said.

“It can asphyxiate you,” he said.

Propane can be especially deadly even if not ignited. When it changes from liquid into a vapor, it expands in volume by about 270 times, so even a small leak of liquid propane can result in a surprisingly large quantity of propane vapor being released.

Still, police cannot assume the propane leak killed Tozier because of his age and his history of heart problems, D’Angelo said.

A doctor in Lincoln working for the state medical examiner’s office performed an autopsy on Thursday, but toxicology test results won’t be available for several weeks, said Sheila Thayer, an administrative aide at the office.

Information on the number of propane gas-related deaths reported statewide or nationally wasn’t immediately available Friday.