Bomb disposal officers on Sunday finally defused a 450kg (1,000 lbs) wartime explosive buried deep below a construction site in Wan Chai, after 26 hours of road closures, mass evacuations and a delicate operation to render it safe. It was only the second time in Hong Kong history that such a large bomb had been discovered in the downtown area, and it brought parts of the district to a standstill. Police experts began the final process to disarm the unexploded second world war ordnance, buried 25 metres deep, at 1am and accomplished their mission 12 hours later. Using pressurised water and sanding, they cut holes in the cigar-shaped free-fall bomb to incinerate the explosive material inside before it could be safely removed from the site. No one was injured. “The whole process was quite complicated. It took a bit longer than we expected,” said senior police bomb disposal officer Tony Chow Shek-kin, standing next to the hollowed out American-made AN-M65, thought to have been dropped by US warplanes sometime between 1941 and 1945. “Once we cut the first hole, we realised it would be difficult to cut holes in other areas ... as some angles were harder to approach. Because the bomb was so big, we had to cut several holes to burn off the explosives inside. The space was tight and the bomb was also slanted at an angle.” 1,300 evacuated as Hong Kong police defuse unexploded 450kg American bomb at Wan Chai building site Had it gone off, the 225kg of explosives could have sent shrapnel flying up to 2km, Chow said. “The shock wave and impact of the bomb could easily have measured 200 to 300 metres. The windows of buildings in the area would have probably shattered and it’s possible those nearby would have collapsed,” he said. The device, 140cm long and 45cm in diameter, was discovered by construction workers at a building site for the Sha Tin-Central rail link on Harbour Road and Tonnochy Road on Saturday morning. Several busy thoroughfares across north Wan Chai, including most of Harbour Road and Convention Avenue, were partially shut to traffic as the bomb squad was called in. The nearby Harbour Road Sports Centre was also closed. More than 1,300 residents, hotel guests and office workers were evacuated from the area, a process Chow said took more time than expected. The area within a 400-metre radius was cleared while officers spent more than five hours on Saturday afternoon protecting the site using sandbags. At least half a dozen cross-harbour and Hong Kong Island bus routes were affected, while Star Ferry services between Tsim Sha Tsui and Wan Chai were suspended. By 4pm on Sunday, most of the main roads in the area, including Convention Avenue, Hung Hing Road between Wan Shing Street and Expo Drive, and Tonnochy Road between Gloucester Road and Convention Avenue, had reopened to traffic. Public transport gradually resumed normal services. The Star Ferry reopened at 4pm. The bomb squad initiated the process of burning off the explosive material inside the device at around 11am on Sunday. The operation was complete at 1pm and the empty bombshell was taken to the squad’s headquarters. Police dispatched more than 10 experts from the Explosive Ordnance Disposal Bureau to conduct the operation, including veteran Adam Roberts, who spent his birthday on Saturday defusing the device. Roberts was also part of the team that defused a 900kg AN-M65 unexploded American bomb found at a construction site in Happy Valley in 2014, in an operation that saw 2,000 people evacuated from the surrounding area.