Abstract: Sewage tanks have been widely used in petrochemical enterprises.Since the components of the sewage medium during production process are complex with flammable,explosive and corrosive medium containing sulfur and oil,these bring certain safety risks to production.This paper aims at the deflagration accident of acid water tank in Yangzi Petrochemical Co.,Ltd.on June 9,2014 and discusses the existing safety risks of the sewage tanks in petrochemical enterprises from the perspective of intrinsic safety.Then it puts forward the solutions.