A fire has broken out at Ferrybridge power station, near Castleford.
Huge plumes of black smoke could be seen coming from the facility, which is often referred to as "Ferrybridge C".
West Yorkshire Fire and Rescue Service dispatched about 50 firefighters and 10 pumps to the site at about 14:00 BST.
Yorkshire Ambulance Service said it had sent a hazardous area response team to the coal-powered fire station. No people are reported to be trapped at the site.
BBC Travel News said there was slow traffic on the M62 in both directions between Junction 32 at Pontefract and Junction 33 at Ferrybridge Services because of smoke blowing across the road.
The A1(M) is also affected between junction 42 for the A63 and junction 41 for the M62. The B6136 Stranglands Lane in Knottingley is closed.
Ferrybridge power station is situated on the River Aire and is the third coal-fired power station to be built on the site since 1924.
The power station first fed electricity into the national grid in February 1966.
It is operated by SSE, formerly Scottish and Southern Energy.
