Amnesty International cites ` ` serious deficiencies and failures '' It supports Shell 's assertion that the vast majority of spills are caused by sabotage and theft . `` We seek to bring greater transparency and independent oversight to the issue of oil spills , and will continue to find ways to enhance this . Shell calls the report 's findings ` ` unsubstantiated '' and continues its analysis of individual cases .
Amnesty International cites ` ` serious deficiencies and failures '' It supports Shell 's assertion that the vast majority of spills are caused by sabotage and theft . Shell calls the report 's findings ` ` unsubstantiated '' and continues its analysis of individual cases .