One person is feared dead and a major incident has been declared following the collapse of a building at Didcot A Power Station.
South Central Ambulance Service said it has sent its hazardous areas response team to the site, as well as three ambulances and the air ambulance.
A spokesman said: “We are describing it as a major incident.”
Oxfordshire County Council deputy leader Rodney Rose said the fire service confirmed one person had died.
Thames Valley Police confirmed officers were at the scene but have not released further details.
Twitter users have described an “explosion” as well as “loads of dust”.
Thames Cryogenics tweeted: “Big collapse just happened at Didcot Power Station. Loads of dust. Not sure if it was planned.”
Adrian Redhead, who lives about a quarter of a mile away said he had just got home from work after 16:00 when he heard a “massive noise”.
He said: “It sounded like a train had come off the rails. Sirens were all over the place. I looked outside and saw all the dust. There were loads of emergency vehicles.
“There are two helicopters above now. A load of dust came over the house.
“I’ve heard there are people inside.”