An oil pipeline blast in the city of Qingdao on November 22，2013 has revealed a startling fact：numerous Chinese cities are faced with high environmental risks caused by an improper distribution of chemical and petrochemical plants and facilities.A sharp increase in the number of sudden environmental incidents would be unavoidable if no effective risk countermeasures were taken.It is necessary to find solutions to the issue of cities besieged by chemicals，and to improve environmental impact assessment （EIA）on relevant development plans and even strategic environmental assessment （SEA）in a broader scope，although no remedy seems to be available for environmental legacy problems.