A double-decker bus carrying 70 Hinkley Point C workers overturned in Somerset due to icy road conditions.
At around 06:00 GMT, police responded to a major incident on the A39 near Cannington, which also involved a motorcycle.
Avon and Somerset Police said there were 70 people on the bus and 54 people were treated at the scene, but there were no fatalities.
Bridgwater MP Ian Liddell-Grainger said three people were seriously injured.
Avon and Somerset Police said 26 of the 54 patients were “walking wounded” and were being treated at Bridgwater minor injury unit and Southmead Hospital in Bristol.
Soon after noon, the police confirmed that the crash was no longer being treated as a major incident.
The crash site is about eight miles from the nuclear power plant, which is currently under construction.
“Emergency services are on the scene, and travel to and from the site has been suspended,” said a Hinkley Point spokesman.
The power plant has not yet commented on the number of workers involved or the number of injuries.
Charis Ware, 45, who lives close to the scene of the crash, told BBC West she was woken by “banging, shouting and horns blowing and screaming”.
She said she counted at least 20 emergency vehicles on the scene.