The ratings include pesticide hazard for the farm field, each applied pesticide product, and each active ingredient in the pesticide products.
Hazard ratings are computed for leaching, solution runoff, and adsorbed runoff, both hazard to humans and to fish, therefore six ratings total for the farm field, each product, and active ingredients in the products.

To compute a hazard rating involves several steps:

• Soil mapunits intersected by farm field geometry, soil pesticide loss potentials computed for each mapunit soil component, and a weighted average loss potential calculated for the farm field;
• Loss potentials computed for each pesticide active ingredient applied to the farm field;
  
• Soil pesticide interaction loss potentials computed using output from steps 1 and 2; and finally
  
• Hazard ratings computed using output from step 3 and pesticide toxicity properties.