When a release of hazardous substances has occurred or threatens to occur, federal, state, local government or industrial personnel may have to assume responsibility for immediate and planned removal. This is the principal cleanup and treatment phase, which sometimes is followed by a remedial action phase. Remedial action is not addressed here. This paper describes a methodology to assist response personnel in selecting optimum countermeasures consisting of (1) assessment of the release site to identify hazardous substances or wastes, media impacted and site-specific parameters (such as topography, climate, and proximity to inhabited areas); (2) insertion of results of (1) into Tables 'A' which classify the known hazardous substances according to physical behavior and specific hazards on release to the known media; (3) insertion of results of (2) into Tables 'B' which indicate one or more technically feasible countermeasures, ie., on-site or off-site cleanup or treatment processes; and (4) making a final or optimum selection from these processes through use of Tables 'C' which apply criteria and constraints such as availability, cost speed or deployment and site-specific parameters. The paper concludes with a worked example of the application of the entire methodology to a real situation. Given a reasonable amount of knowledge about the release, a person with limited background can use the methodology to arrive at workable removal countermeasures.