Shortly before 9 pm on Sunday, April 2, Sandy Hook volunteer firefighters were alerted by a person who was outdoors in the Riverside neighborhood that there was a strong odor of propane in the air there, near the intersection of Underhill Road and Waterview Drive, in the area that overlooks Lake Zoar.

Sandy Hook Volunteer Fire & Rescue Chief Bill Halstead said firefighters quickly responded to Riverside and traveled through that area, checking for concentrations of the colorless gas, which often is used as a domestic heating fuel.

Firefighters found a couple of places where there were propane concentrations, he said, adding that they then went from house to house in the neighborhood in seeking to find the place from which that bottled gas was escaping into the atmosphere.

When they arrived at a single-story house at 106 Underhill Road, firefighters found that the bottom end of two upright, outdoor propane storage tanks had frozen, signifying a possible problem, Chief Halstead said. That residence uses two 120-pound propane tanks to fuel a furnace and a fireplace, he said.

On checking with the two adults who were inside that house, firefighters learned that the occupants had not noticed the odor of propane inside the building, although the gas's distinctive smell inside the house was noticed by firefighters, Chief Halstead said. The smell of propane was obvious to anyone who was outdoors in that area, he added.

A gradual buildup of the gas within the house apparently had resulted in the two occupants simply not noticing the gas and not realizing that there was a problem, the fire chief said.

Chief Halstead said the propane gas leakage amounted to "a very dangerous situation," which fortunately was resolved without incident. Under certain conditions, accumulated propane, which is heavier than air, poses the risk for explosions and fires.

There was an accumulation of propane in the living quarters of the house and a "high concentration" of the hazardous gas in the basement, Chief Halstead said.

Firefighters used large fans to blow the gas out of the building. There were no injuries in the incident, in which no physical damage occurred.

The propane firm that supplies the residence was called in to resolve the propane system leakage problem, the fire chief said.