On 11 September 2002, National Security Council (NSC) staff contacted the CIA to clear language for possible use by the President, Bush. The language cleared by the CIA said, "Iraq has made several attempts to buy high strength aluminum tubes used in centrifuges to enrich uranium for nuclear weapons. And we also know this: within the past few years, Iraq has resumed efforts to obtain large quantities of a type of uranium oxide known as yellowcake, which is an essential ingredient of this process."