The annex of a women-only spa facility in Tokyo’s Shibuya Ward that was destroyed Tuesday in an explosion, killing three women and injuring eight people, was probably not equipped with a gas detector, police said Wednesday.
Sources said equipment to separate and release into the atmosphere methane that rises with hot water when the water is piped from 1,500 meters underground probably had not been checked since the spa opened in January 2006.
Police focused their investigation Wednesday on whether the methane may have become trapped inside the Shiespa building, causing the blast.
Police also questioned Shiespa’s operator, Unimat Beauty and Spa Inc., to determine how the facility was managed and searched the firm’s premises. The company, however, claims the annex basement was equipped with a detector, and said a security alarm at the office of the main building would have gone off if there were any problems. The company said it found no problems before the accident.
But police said they have yet to find a detector at the site. They plan to question company officials about how the detector and alarm were installed and operated, they said.
The explosion, which destroyed the annex building, killed Mari Hizume, 51, Hiromi Fujikawa, 22, and Akina Senzai, 23. They were all Shiespa employees, police said.
Two of the eight injured — Naomi Kitamura, 35, and Kimie Ikeda, 32 — were also employees, while a third was a 28-year-old male passerby.
At the annex, natural gas that rises when hot water is piped from underground was supposed to go through a gas separator and then vented outside by fan. Police suspect that some fault in the exhaust system allowed natural gas to fill the annex building.
The Tokyo Metropolitan Government said it started checking the safety procedures at 144 spa facilities under its jurisdiction. It will try to determine if the facilities are properly ventilated to ensure there is no threat of trapped gas.