A massive fire at Philadelphia Energy Solutions Inc’s oil refinery on Friday damaged the largest U.S. East Coast plant to the point that it could remain shut for an extended period, according to Philadelphia city officials and company sources. Philadelphia fire officials said several explosions sent a huge fireball into the sky, engulfing the surrounding areas in smoke after 4 a.m. EDT (0800 GMT), following the ignition of a fire that started in a butane vat at the 335,000 barrel-per-day (bpd) refining complex, also the oldest in the Northeast. By mid-afternoon, the city’s fire department was working with PES in its response to the fire, though it was letting the flammable gases burn under control. PES said in a statement it believed the product that was burning was “mostly propane.” Four workers were injured, according to a company statement, and treated on-site, while city emergency workers […]