 Milligan 's investigation , completed in July , concluded that the explosion was caused intentionally by a Turret Two crewman named Clayton Hartwig who Milligan believed was suicidal and homicidal . Milligan also found that , under Moosally , Iowa was operating with severe training and safety deficiencies . The finding that the explosion was intentionally caused by Hartwig was heavily criticized by the victims ' families , the media , and members of Congress . Most of Iowa 's crewmen also did not believe that Hartwig was responsible for the explosion . 
