Iraq is searching for "highly dangerous" radioactive material stolen last year, according to an environment ministry document and seven security, environmental and provincial officials who fear it could be used as a weapon if acquired by Islamic State. The material, stored in a protective case the size of a laptop computer, went missing in November from a storage facility near the southern city of Basra belonging to U.S. oilfield services company Weatherford (WFT.N), the document obtained by Reuters showed and officials confirmed.