On April 2, a team of specialists moved in on a burning tanker truck and blew up the remaining fuel cargo.
It ended an emergency highway closure that started with a crash and a fireball alongside Highway 16 on March 29 when an eastbound B-train carrying two tanks of propane lost control and exploded (the driver survived). An evacuation zone was set up around the site, about halfway between Prince George and McBride.
One tank erupted immediately in a blast that could be seen for about 10 kilometres, but the second tank streamed fire for days on end.
Experts calculated that there was at least one and perhaps two weeks of burning still ahead, at the rate of flame and the amount of fuel known to be on board. There was a strong worry that the tank's steel wouldn't hold for that long and an unpredictable blast might be the result.
LPG Emergency Response Corporation, a Calgary-based firm contracted with Transport Canada, was called in to defuse the incident, in concert with other authorities.
The LPG team was led by Scott Blaney who told The Citizen on Wednesday how rarely such incidences occur.
"I have been in this business for a little over 20 years, and a road tanker like this, this is the first incident I have seen of this nature," he said.
Blaney went on to explain the so-called "vent and burn" procedure that was used to end the incident.
"The 'vent and burn' is a procedure we like to call a last resort," said Blaney.
"One case out of a million, we will have to turn to this option. We have two or maybe three people go in and do that so there are fresh sets of eyes looking at all factors -- the damage to the tank, the damage to the valves, the shape and position of the tank -- and then we make decisions based on that assessment."
The team saw a small fire coming from one of the valves, the Spray Fill Line, and found they could not connect to any of the other valves to do a standard transfer or a standard flare.
"There really was no other way to extract the product form the tank, other than doing a 'vent and burn.' It was not a spur of the moment decision; it took a couple of days to come to that decision."
Blaney said the decision was made after much discussion among "all the players" in government and industry to call in an explosives specialist team - a two-person team that works with LPG Emergency Response Corporation.
"It was a very calm moment. We understood that we had to do what we had to do, to alleviate the risk to the public and the environment, and I believe we took the correct action."
Once called in, the explosives experts made their own assessment.
"They don't just take our word for it," said Blaney.
The team then set two charges - one for the vapor phase and one for the liquid phase, "hence the 'vent and burn' terminology," said Blaney.
The first small charge is detonated to vent and bring down the pressure on the tank.
"It creates a vent in the top of the tank and the vapor portion goes out that hole," said Blaney.
The second charge is for evacuation of the liquid portion. It creates a pool of product which is ignited and burns off.
"It is a very very quick process, actually. The whole procedure takes 15 to 20 minutes, depending on the amount of product in the tank."
In this case, it took 20 minutes or less.
It was an excellent real-life test case for the extensive training the company's employees undergo.
"The research and development used for our training turned out to be exactly applicable to this situation. It was textbook."
The cause of this crash is still under investigation by the RCMP.
