Conventional capping of contaminated sediments with sand or other inert materials may not be effective in areas where sediments contain nonaqueous phase liquids (NAPL) due to displacement or continued migration of NAPL. The NAPL may migrate as a result of the disturbance related to capping of the sediment, subsequently during consolidation or as a result of gas release. Organoclays can be an especially effective means of addressing migration of NAPL and mobile dissolved phase hydrophobic organic compounds. The use of organoclays in laboratory, field demonstration, and full-scale field applications is presented. The effectiveness of organoclays in these applications and approaches to effectively place the material in the field are described. This is an abstract of a paper presented at the AIChE Annual Meeting (Salt Lake City, UT 11/4-9/2007).