Eight fire engines were called to the scene after thick smoke was seen billowing from the building.
A fire broke out in a turbine within the building. Power station owner E.on said there were no injuries and the fire had been contained within the building.
For safety reasons fire crews were not able to gain access to the building for two hours.
Fire fighters tackling the blaze were brought out of building shortly before 12pm. But they are expected to remain at the plant for most of the day while they damp down. Relief crews are expected to take over at 2pm and an investigation into the cause is still underway.
Firefighters from from Bridgnorth, Wellington, Telford, Shrewsbury, Tweedale, Much Wenlock and Prees were all sent to the station in Buildwas Road at around 6am.
They were joined by a high high volume pumping unit from Prees, a foam unit, command support unit and support pump from Tweedale and four operational officers.
A spokesman for Shropshire Fire and Rescue Service, said: "We had to wait for all the electrics to be made safe.
"That was confirmed at 7.53am and then we carried out a full risk assessment before starting to tackle the fire.
"While the assessments were being carried out we had crews ready with hose reel jets, main jets and breathing apparatus."
It was not clear if the station was producing any power today, although E.on said supplies to homes and businesses in the area would not be affected.
Employees turning up for work today were directed to another part of the site by security staff.
Buildwas Road was closed while emergency services attended the blaze with drivers diverted along the Warfage.
James Ashton, force duty inspector for West Mercia Police, said: "We were contacted by the fire service at around 6.30am this morning in relation to a fire at Ironbridge Fire Station.
"We were asked to attend for traffic control purposes. We have got officers on the scene and are currently working on assisting with road closures."
Mr Ashton added he did not believe the fire was dangerous for the public.
The site, which is famous for its pink cooling towers, is currently the only major generator of electricity in Shropshire.
The plant consumes about 1.2 million tons of coal and 20,000 tonnes of oil each year.
A man who has worked at the power station for 31 years who did not want to be named said: "The smoke is coming out of the turbine hall.
"There are two generators in there. The last time this happened, around 15 years ago, it took the roof off.
"But it does not look as bad this time. A power station is not a good place to have a fire. There is lots of spinning machinery, oil, gas and hydrogen.
"They will have a good fire plan in place. At that time of day there would have been between eight and 10 people working but in the day it's more like 100."
Power stations have occupied a site on the banks of the River Severn at Buildwas since 1932, but the present power station is sue to close in 2015. Under European Union directives, ageing plants like Ironbridge have been legally limited in the emissions they can produce.
Ironbridge's operating hours were restricted in 2008 and its forthcoming closure was later announced.
The area was chosen for the station due to its close proximity to the River Severn and several railway lines which provided excellent access to both cooling water and a source for the delivery of coal.
Work began on Ironbridge B Power Station in 1963 however, it did not begin feeding power into the National Grid until the June 1969.
The cooling towers were deliberately constructed using concrete to which a red pigment had been added, to blend with the colour of the local soil.
The station's single 673 ft high chimney is fifth tallest chimney in the UK. It is the tallest structure in Shropshire, as well as being taller than Blackpool Tower and London's BT Tower.
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