On the early morning of June 21st, 2019, an explosion occurred at Philadelphia Energy Solutions, an oil refining complex in the southwest part of the city. A large fireball filled the night sky. The fire continued to burn until daybreak. A deputy fire commissioner with the Philadelphia Fire Department discovered a fire stemming from a vat of butane, a colorless gas that is highly flammable. About 120 employees from the Philadelphia Fire Department responded to the explosion and worked with firefighters from the facility to put out the flame. By 7 a.m. the shelter-in-place order had been lifted, but commuters were still advised to avoid the area.