The story of a 2013 explosion in Saanich is at the forefront of a WorkSafeBC campaign about the dangers posed by repurposed shipping containers.
At the centre of the campaign is a promotional safety video based on the shipping container explosion that rocked the construction site at the corner of Cloverdale and Inverness. The well-documented explosion blasted the steel doors off the container hinges, injured one on-site crew member, and was heard from as far away as Oak Bay.
At the time, the construction crew for the development (the Midtown Park condos) was using large shipping containers as offices and storage units. In one of the containers, the valve of a barbecue propane tank was accidentally left on over night. The propane tank drained out and turned the sealed container into a time bomb. The next morning an electrical spark from a pop machine ignited the gas in a major eruption.
The power of the explosion blasted the 113-kilogram doors off the container. They flew 40 metres and landed in Rutledge Park. The problem was the heavier-than-air propane sank to the bottom of the container below the vents, which are up high and were unable to ventilate the container.
The only injury was sustained by a construction worker who was standing in a shipping container adjacent to the explosion. He was thrown violently but suffered non life-threatening injuries.
The trend of repurposing shipping containers, or sea cans, as offices or storage units has become a popular one. Resale companies such as seacan.com sell a variety of containers. A standard model – which are about 10 feet long, 8.5 feet high and eight feet wide – sell for $3,995.
“Shipping containers are being repurposed all over B.C.,” said Dan Strand, director of prevention field services with WorkSafeBC. “The containers are designed to be watertight, which means they are well sealed with little or no ventilation, ideal for shipping purposes but potentially dangerous for other uses.”
Vapours or gases from common flammable or combustible substances, when combined with an ignition source in a container with little or no ventilation, can produce a catastrophic incident. A leak of just one kilogram of propane, for example, can rupture a closed shipping container; the propane tank on an average home barbecue holds nine kilograms. A full tank can generate the same explosive force as 100 kilograms of TNT.
While the Midtown explosion went off without tragedy, a 2011 incident led to the death of a volunteer firefighter.
The volunteer firefighter was struck and killed by a door that blew off a shipping container while he was fighting a fire in the next building. Afterward, investigators found that the container was being used to house a collection of gas-powered tools. When the fuel vapour was exposed to extreme heat, the container exploded.
Other risks in shipping containers include floorboards which may have been treated with toxic chemicals, or residual chemicals which may have spilled in transit, both of which can overcome unsuspecting workers.