The EPA, recognizing the need to assess, modify, and evaluate procedures and equipment applicable to working in contaminated underwater environments, entered into an interagency agreement with NOAA. As part of this work, an 'Interim Protocol on Underwater Operations' was developed and is the subject of this paper. The Protocol was based upon preliminary field evaluations of diving equipment in controlled chemical underwater environments. Following a peer review of the document by the user community, the methods, procedures, equipment, and training will be applied at a number of sites or spills of opportunities. The resulting information will be utilized to prepare a 'Manual of Practice (MOP) on Underwater Operations in Contaminated Waters.' The final MOP is scheduled for publication in December 1984.