BERUIT (AP) - At least 10 times over the past six years, authorities from Lebanon’s customs, military, security agencies and judiciary raised alarm that a massive stockpile of explosive chemicals was being kept with almost no safeguard at the port in the heart of Beirut, newly surfaced documents show.Yet in a circle of negligence, nothing was done — and on Tuesday, the 2,750 tons of ammonium nitrate blew up, obliterating the city’s main commercial hub and spreading death and wreckage for miles around.President Michel Aoun, in office since 2016, said Friday he was first told of the dangerous stockpile nearly three weeks ago and immediately ordered military and security agencies to do “what was needed.” But he suggested his responsibility.