U.N. Secretary General Kofi Annan has exonerated his former chief of staff who was charged with shredding documents related to the oil-for-food humanitarian programme in Iraq, a spokesman said Thursday. The aide, Iqbal Riza, who retired earlier this year, was charged by the Independent Inquiry Committee, headed by former U.S. Federal Reserve chairman Paul Volcker, with shredding documents that would have helped an investigation into the scandal-ridden programme. Riza said the shredded papers were copies of formal documents related to the aid plan and the shredding was done to gain space for new documents. The U.N. headquarters is known as a paper mill because of the tens of thousands of documents it issues every year. "While those actions were careless, I do not believe they can be construed as deliberate attempts to impede the work of the Independent Inquiry Committee," Annan said in a letter to Riza after the latter sent a letter to apologize for the shredding according to dpa. --More 2346 Local Time 2046 GMT