The terms of reference of the GESAMP EHS Working Group, as given by GESAMP at its 6th session in Geneva (1974) and amended at its 8th session in Rome (1976) are:
"To examine and evaluate data and to provide such other advice as may be requested, particularly by IMO, for evaluating the environmental hazards of harmful substances carried by ships, in accordance with the rationale approved by GESAMP for this purpose".
The "rationale" for hazard evaluation specified for the Working Group was initially laid down in GESAMP IV/19/ Supp. 1. This was replaced in 1982 by GESAMP Reports & Studies No. 17, which was in turn superseded by Reports & Studies No. 35 in 1989. As approved by GESAMP at its 28th session in 1998, the present procedure (R&S 64, 2001) replaces all previous versions. The terms of reference remain the same.