Explosion occurred during dinner rush at second-floor restaurant.
At roughly 8:30 p.m. on the night of December 16 the Sapporo Fire Department received a call that an explosion had occurred near Hiragishi subway station in the city’s Toyohira Ward. When they arrived n the scene, they found that a two-story building had gone up in flames.
https://www.youtube.com/watch?v=CXTmIUrdqWo#t=0m15s
Three tenants had been renting space in the building: a real estate agency and osteopathic clinic on the first floor and an izakaya (Japanese-style pub) on the second. While some initial reports assumed the explosion had originated in the izakaya, investigators initially thought there may have been a problem with the real estate agency’s extrernally installed propane gas tanks.
▼ The scene of the fire the following morning
Customers and staff of the second-floor restaurant having to evacuate by going out the windows, and 42 people suffered injuries related to the explosion. Glass and rubble were scattered far from the building’s foundation, and the falling building also destroyed an adjacent fishmonger’s shop and damaged a nearby building which houses a clinic and cram school.
▼ A before/after comparison of the location shows the building with its bright blue real estate agency sign in the left photo, and a charred void in the right.
Miraculously, despite the startling property damage, no one was killed in the explosion and ensuing fire, which flung debris far enough to shatter the window of a condominium some 50 meters (164 feet) away from the blast.
Update: Fire department and police investigators are still working to determine the exact cause of the gas tank fire, though they suspect it may have started due to flammable cleaning/deodorizing sprays present inside the real estate agency (an employee admits to placing nearly 100 canisters, with holes in them and meant for disposal, near the office’s water heater) which then ignited due to an electrical spark or static electricity form the occupants’ clothing.
Sources: NHK News Web, The Sankei News, Hokkaido Shimbun, Otakomu, Hachima Kiko, NHK News Web (2), Kyodo