Authorities have described it as a "major incident" as six ambulances and two air ambulance rushed to the Didcot Power Station in south Oxfordshire. Thames Valley Police tweeted, "Officers are at Didcot Power Station at an incident with other emergency services. Further details will be released in due course".
The site is home to a combined coal and oil power plant, which has been closed and partly demolished. The disused coal-fired power station ceased generating in 2013 and three enormous cooling towers were demolished at the site in 2014.
South Central Ambulance Service said it was "describing it as a major incident". Witnesses described hearing a loud explosion before plumes of smoke and dust rose into the air.