Guardian: Nearly three weeks after an oil rig explosion turned the Gulf of Mexico into an environmental disaster zone, BP today still casting about for a clear plan to shut off the gusher of crude that has cost the company $350m (£235m). BP crews were simultaneously exploring a number of different approaches to plugging the leak, known in industry slang as top hat, top kill, and junk shot. "We are pursuing multiple options in parallel and we are learning all the time," BP’s CEO, Tony …