Firefighters battled to contain a huge blaze at a Pennsylvania chemical warehouse which sent huge plumes of black smoke into the sky early Monday. A reporter from NBC station WGAL reported hearing explosions around the Miller Chemical warehouse in Conewago Township as he arrived at the scene near Hanover, Pennsylvania. Officials issued a shelter-in-place notice for residents within a mile radius of the warehouse, according to Adams County Emergency Dispatch. It said hazmat crews along with local and county emergency management teams were on the scene.