Expert doubts dozens rocket could carry enough chlorine to kill one . United Nations affiliate reports results of blood and soil testing sent to CNN . Sources tell CNN that chlorine mixed with saline was used in attack . Rebels have said they have no access to chemical weapons .
Expert doubts one rocket could carry enough chlorine to kill dozens . CNN affiliate reports results of blood and soil testing sent to United Nations . Sources tell ITN that chlorine mixed with saline was used in attack . Rebels have said they have no access to chemical weapons .