Shropshire Fire and Rescue Service along with RAF Cosford personnel and emergency services staff are currently taking part in a training exercise at the iconic Ironbridge power station site.
The exercise is based on the scenario of a fast jet and a military helicopter collision over the power station site.
The RAF have warned residents not to be alarmed and to expect large numbers of emergency vehicles in the area.
Later today, a small amount of non-toxic blue water dye will be placed in the River Severn to simulate an environmental spillage. The use of the dye has been approved by the Environment Agency and will have no adverse impact on local wildlife or water supplies.
Access is restricted and no activity is visible from outside the site.