The Norwegian pesticide risk indicator (NERI) was developed with a dual purpose, as a tool to assess the risk of pesticide use and as a method for taxation of pesticides (Stenrød et al., 2008). Like EIQ, NERI is a rating system. For human health, NERI classifies products into 4 risk classes (low, medium, high and very high risk) according to the risk phrases on the label. NERI also considers the risk of operator exposure when preparing the spray mixture and when applying the pesticide by multiplying the scores for human health with scores for formulation type and application method.

Environmental risk is assessed by adding up scores for effects on earthworms, bees, birds, aquatic organisms, mobility and leaching potential, persistence, bioaccumulation and a score for formulation type. Based on the accumulated score, NERI classifies products into three environmental risk classes. By combining the information on human health and environmental risk, classifications products are grouped into 7 pesticide tax classes.

A total environmental risk index is calculated for each active ingredient in each individual product. The total environmental risk index, for each individual active ingredient in each product is multiplied by the area on which the product is used a particular year, to give the relative environmental load from a specific pesticide. These indices are summed for the area and time period investigated to obtain a cumulative risk index.