The explosion that ripped through the 5,600-square-foot home at 1470 Hilltop Lane in East Berne, N.Y., on Friday June 4, 2021, killed two people and reduced the structure to rubble.

An orange glow from fire and a plume of smoke could be seen from about five miles away from a house explosion in the town of Berne, N.Y. on Friday, June 4, 2021. This image was taken with the use of a drone.

The remains of the home at 1470 Hilltop Lane in East Berne, N.Y.  that exploded just before 8:30 p.m. Friday, June 4, 2021, killing two people.

The explosion that ripped through the 5,600-square-foot home at 1470 Hilltop Lane in East Berne, N.Y., on Friday June 4, 2021, killed two people and reduced the structure to rubble.

BERNE – When an explosion leveled a Hilltop Lane home and killed its owners last summer, investigators quickly settled on a propane leak and an appliance's spark as the likely cause of the blast.

A recently completed state investigation reached the same conclusion, finding "fugitive" propane vapors leaked from an uncapped supply line in the basement of 1470 Hilltop Lane in the hamlet of East Berne and were ignited by an electrical spark from an appliance.

The late-night explosion on June 4, 2021, killed Lois Porlier, 72, and her 83-year-old husband Victor. Both were well-known members of the community.

The state Office of Fire Prevention and Control investigation of the explosion concluded it was an accident.

Autopsy results revealed that the couple died from blunt force trauma caused by the powerful blast that blew apart their home and unsettled neighbors and friends in the surrounding Hilltowns community.

The 20-page OFPC report, obtained by the Times Union through a Freedom of Information Law request, indicates the sources of power and heat at the three-story, wood-frame, modern-style home included propane, electricity, geothermal heating, and photovoltaic panels.

“The fire investigation team was able to determine that the explosion and subsequent fire was a result of fugitive liquid propane gas vapors from an uncapped supply line within the structure’s basement having been ignited by an electrical arc produced during the normal operation of an appliance in that area,” the report found. Investigators were unable to pinpoint which appliance delivered the triggering spark. 

The term fugitive emission refers to the unintentional emission, leaking, or discharge of gases or vapors from pressure-containing equipment or facilities, and from components such as valves, piping flanges, pumps, storage tanks and compressors among other things, according to information online.  

Through interviews with neighbors and first responders, a team of state fire investigators determined that a propane company on the morning of the catastrophe had delivered two propane tanks to the house and that “there was information provided indicating the presence of smoke alarms and that the dwelling was in fairly good condition."

It was unclear in the report if those smoke alarms were working.  

One neighbor, Robert Alteri, told investigators that in July 2020 he helped Victor Porlier remove a propane refrigerator-freezer unit after they disconnected the propane supply line. Alteri said he offered to buy a cap and seal the end of the line but that Porlier said he would install the cap later. 

The findings include more than 200 digital photos along with relevant measurements illustrating the absolute devastation with debris and charred items strewn all around the property. It also features a diagram identifying the “known utilities,” such as two water heaters, distribution panels, a water softener system, generation and photovoltaic charge controller all inside the residence along with two propane tanks on the outside. 

Investigators also conducted a visual inspection of what was left of the home, valued at $435,000. They evaluated fuel packages and fire patterns, testing out several theories before concluding that “the most intense area of damage had occurred within the basement of the structure.”  

The intensity of the blast, the report states, caused the structure to shatter sending small pieces of debris flying. Some pieces landed  hundreds of feet away, in what investigators described as "high order structural damage."

In trying to pinpoint the cause of the blast, investigators systematically eliminated things such as the cooking equipment, heating systems, smoking materials (neither Porliers smoked), spontaneous heating and chemical agents, open flames and sparks and anything related to the vehicles. 

The potential causes of the deadly explosion and fire pointed to “electric sources” connected to arcing from a light switch, the operation of the water-well pump, a heat pump within a furnace or from the operation of a dehumidifier.

“The normal operation of these identified items or other pre-existing appliances not identified could not be eliminated as the ignition source of the fugitive liquid propane vapors,” OFPC lead investigator Kristi Geary wrote in the state report. 

She worked on the case with three other colleagues and a specially trained dog.            

The team's search for a fuel source capable of supporting an explosion led them to focus on information from a neighbor that in July 2020, a propane-fueled appliance had been disconnected from the end of quarter-inch section of brass tubing.

“No information of evidence was identified indicating that this supply line had been capped following the appliance removal,” the report states, adding that on the morning of the fatal explosion, a propane company filled two propane tanks “servicing the structure.” 

“An uncapped propane supply line within the basement could not be eliminated as a probable source of the fugitive liquid propane gas vapor source for the explosion,” the document indicates.  

Propane gas is naturally colorless and odorless. But propane manufacturers add a harmless chemical to give it a noticeable odor. A propane leak makes a hissing sound.

While simply smelling propane is often how propane leaks are discovered, users can also check propane tanks on a regular basis by applying soapy water or specialized leak detector solution to the tank’s cylinder gas supply valve or regular outlet connection. If bubbles form when you slowly open the cylinder valve, there’s a chance of a propane leak.

Albany County Sheriff Craig Apple said Tuesday that the OFPC findings about the cause and origin of the accidental explosion  only bolsters what his investigators suspected and now paves the way for the agency to close out its criminal probe.

It's just a very sad and tragic event," added Apple. "It probably gives the family some closure, and again  it's just a horrible accident, but I'm glad we can finally close it out."     

Paul Nelson covers cops and courts in Schenectady County as well as the suburban towns of Niskayuna and Rotterdam. Contact him at pnelson@timesunion.com or 518-454-5347.