Using existing data to make decisions about chemical countermeasure products

The use of chemical countermeasure products (CCPs) (i.e., dispersants, herding agents, emulsion-treating agents, solidifiers, elasticity modifiers, and shoreline-cleaning agents) in treating oil spills has been hindered in the United States by the perceived lack of data or apparent conflicting data claims concerning their effectiveness and toxicity. Recognizing that important data exist, such as in the technical bulletins for the National Contingency Plan Product Schedule, an expert workshop was convened to achieve consensus on (1) the adequacy of existing effectiveness and toxicity data and (2) how best to interpret and use those data to enhance oil spill planning and response. Through a deliberative process, consensus was reached in three topic areas: environmental effects, effectiveness, and decision making. Discussions emphasized dispersants because considerable information is available on them, but other CCPs were considered. The following conclusions were reached: (1) there is a dispersed oil concentration threshold below which no ecological effects are expected in open marine waters; (2) there is a low probability that meaningful monitoring data will be available within the response period; (3) multiple applications should be encouraged; and (4) a recommended outline for a reference document on implementing dispersant prespill planning should be developed. This paper summarizes the conclusions in each of the topic areas, including the rationale for the experts consensus and prespill planning needs.