Emergency services are responding to an incident at a Rolls-Royce factory in Derby.
Derbyshire Fire and Rescue Service said it was called to the site in Raynesway shortly after 16:00 GMT on Thursday.
Fire crews have been joined at the scene by police and ambulance colleagues, who have been seen outside the factory.
Firefighters have advised people in the Alvaston area of Derby to keep their windows and doors closed while emergency services deal with the incident.
A reporter at the scene has been advised by police to stay in her car for her safety, and an alarm has been heard coming from the building.
A number of roads have been closed around the factory, including Royal Scot Way, Pride Park Way, from Derby Audi to the London Road roundabout, Harrow Street, and London Road, from the junction of Harrow Steet to Meadow Lane.