Firefighters said the blaze broke at a maintenance building on the site of Winchester Ammunition plant in East Alton just before 3:30 a.m. Authorities said propane cylinders exploded, but those cylinders were isolated from more dangerous materials. The Winchester fire took place shortly after an abandoned building burned in another part of town. The cause of each fire is under investigation. As this fire broke out in a maintenance building and not a production area, we do not know at this time if ammunition production will be hampered. Weve contacted Winchester representatives, and will update this story as we know more about the fires impact (if any) on production.