A case study of a gasification plant in Harbin was performed using mathematical models,with the consideration of the water quality of waste gasification,conventional processes for removal of pollutants, wastewater discharge in emergency situations and other factors. Health risks caused by the volatile phenol pollution in the surface water environment were analyzed. The results show that the non-carcinogenic health risks caused by volatile phenol in the water are in the range of 1. 67 ×10-7 /a-9. 12 ×10-7 /a,which are less than the acceptable level of non-carcinogenic pollutants. But in the discharge state in an accident in the sewage treatment system,health risks caused by volatile phenol pollution are 5. 3 times of those under normal operating conditions. The health risks value of an accident is 88. 3%-91. 2% of the acceptable level,close to the limits of the acceptable level,and accidents have greatly increased the environmental health risks.