Following the Norwegian authorities' requirements in 1997 of "zero discharges to sea" within the end of 2005, the operating companies on the Norwegian shelf initiated the development of a modelling tool used for guidance of management decisions for reduction of potential harmful environmental effects associated with produced water discharges. This effort was embodied in the DREAM (Dose-related Risk and Effect Assessment Model) project (Johnsen et al, 2000), from which the Environmental Impact Factor for produced water (EIFPW) was developed. The EIFPW is a relative indicator of environmental risk whose purpose is to aid the industry in the development of a "zero harmful discharge" strategy and selection of cost-benefit-based solutions.
The development of the EIFPW was well received by the Norwegian authorities and is now in use by the operating companies on a regular basis, both on the Norwegian shelf as well as in other areas internationally. To develop the idea of a risk based management tool further, the ERMS (Environmental Risk Management System) joint industry program was established to further develop the DREAM model as a basis for calculation of a similar EIF for drilling discharges (EIFDD) .
Following the Norwegian authorities' requirements in 1997 of "zero discharges to sea" within the end of 2005, the operating companies on the Norwegian shelf initiated the development of a modelling tool used for guidance of management decisions for reduction of potential harmful environmental effects associated with produced water discharges. This effort was embodied in the DREAM (Dose-related Risk and Effect Assessment Model) project (Johnsen et al, 2000), from which the Environmental Impact Factor for produced water (EIFPW) was developed. The EIFPW is a relative indicator of environmental risk whose purpose is to aid the industry in the development of a "zero harmful discharge" strategy and selection of cost-benefit-based solutions. 
