Japan ordered inspections of ageing highway tunnels yesterday after a fiery collapse that killed nine people, as suspicion over the cause of the accident centred on decaying ceiling supports.
The government pledged a thorough review and said “significant investment” would likely be required in the highway network, parts of which, including the accident site, were built during the economic boom of the 1960s and 1970s.
“As a major factor, we suspect ageing,” an official from highway operator NEXCO said, referring to the tragedy at the Sasago tunnel, which passes through hills near Mount Fuji, 80km west of Tokyo.
Footage from inside the tunnel showed concrete panels had collapsed in a “V” shape, possibly indicating some kind of weakness in the central supporting pillars suspended from the roof, experts said.
Engineers yesterday began inspections at three other tunnels in the region with the same design, as well as at Sasago.
The Ministry of Land, Infrastructure and Transport ordered emergency inspections of all 49 highway tunnels nationwide that have the same design.
NEXCO said safety inspections consist largely of visual surveys, with workers looking for cracks and other abnormalities, or listening to the acoustics of the concrete and metal parts by hitting them with hammers.
Officials admitted that during the five-yearly check of the ceiling in September there had been no acoustic survey of the metal parts on which the panels weighing up to 1.5 tonnes rest.
Emergency workers were still at the nearly 5km-long tunnel yesterday, but 24 hours after the cave-in, efforts shifted from rescue to recovery.
Three vehicles were buried on Sunday when concrete ceiling panels crashed down inside the tunnel. Witnesses spoke of terrifying scenes as at least one vehicle burst into flames.
Emergency workers had collected five charred bodies — three men and two women — from a vehicle by early yesterday. One report said the victims were all in their 20s.
They also recovered the body of a truck driver, identified as 50-year-old Tatsuya Nakagawa who reportedly telephoned a colleague immediately after the incident to ask for help.
Three other deaths have been confirmed, an elderly man and two elderly women, who were all in the same passenger vehicle, officials said.
“I offer my deepest condolences” to those affected, NEXCO Central president Takekazu Kaneko said. “First and foremost, the rescue operation is our priority. We are also inspecting our tunnels that use the same design.”
Japan’s extensive highway network criss-crosses the mountainous country, with more than 1,500 tunnels. Around a quarter of these are more than 30 years old, according to the Transport Ministry.
The country is also prone to earthquakes and despite a tightening of safety regulations over the last 20 years, older structures could be vulnerable to the regular movements, experts have warned.
Japanese Chief Cabinet Secretary Osamu Fujimura said the government had ordered immediate action to shore up the transport system.
“The prime minister ordered the transport ministry to do its utmost in the rescue operation, to find out the cause at an early stage, to take thoroughly preventive measures against similar accidents,” he said.
“We will have to make significant investment in public transportation systems and will need to ensure its durability. We need to review infrastructure as it ages,” Fujimura said.