One person has been killed and at least four have been injured after the collapse of a former boiler house at Didcot A power station in Oxfordshire, UK.
A search-and-rescue (SAR) operation has been initiated to find three people, who are currently missing and unaccounted for.
The accident occurred on 23 February while the building was being prepared for demolition and an external demolition contractor was working in it.
Manager of the Didcot Power Station site, energy firm RWE npower, said in an online statement: "We are working with the emergency services who are currently on site to understand the cause of this collapse."
The coal and gas-fired power station was closed in 2013. In 2014, three cooling towers at the plant were demolished using explosives.
Rescuers are using sniffer dogs to find the missing people at the 300m-long and ten-storeyed building.
Two drone aircraft are being used in the search operation, according to the BBC.
A rubble pile up to 30ft high is being searched by the SAR teams from Buckinghamshire, Hampshire and the West Midlands.
Oxfordshire assistant chief fire officer Nathan Travis said: "The remainder of the building is very unsafe, which is hampering [the] search. This is a very difficult situation with a very unstable structure.
"The safety of emergency service personnel has to remain our priority, while recognising how hard this must be for families waiting for news of loved ones."
In addition, 50 people were treated for dust inhalation.