The guidance assists regulators and policy makers on the selection of Action Lists and the development of Action Levels for dredged material proposed for disposal at sea. An Action List is a set of chemicals of concern, biological responses of concern, or other characteristics that can be used for screening dredged material for their potential effects on human health and on the marine environment. Action Levels establish thresholds that provide decision points that determine whether sediments can or cannot be disposed of at sea.