According to the Van Yen District People's Committee, the bomb was found in the late afternoon of June 25 by a group of workers digging at a house construction site in Mau Dong Commune.
After being informed by the house owner, the local authorities immediately sent a team to investigate the site.
The bomb which was left from the American War, was 1.20 metres long and 0.45 metres in diameter, the committee said.
Mau Dong Communal Military Command has sealed the area while waiting for the bomb to be disarmed.
Large bombs have regularly been found in Yen Bai. In August 2018, a 350-kilo bomb was also found and successfully deactivated in Van Yen District. Another 340-kilo bomb was discovered and safely defused in Luc Yen District in February 2020.
Local authorities said the US-made bombs were dropped during the US bombing of northern Vietnam from 1968 through to the 1970s.
According to the National Steering Committee for Recovery of Postwar Bomb and Landmines, about 800,000 tonnes of unexploded ordnance (UXOs) were left scattered across 6.6 million hectares – or 20.12 percent of the country’s surface area after the war ended in 1975, mainly in the central region, putting people in danger every day.
By 2020, some 6.13 million hectares of land are polluted or suspected of being affected by UXOs, accounting for 18.82 percent of the country’s total area.
Since 1975, UXO incidents have killed more than 40,000 people and injured 60,000 others.