The division of earth and clay aggregates into the four classes is based on the Environmental Protection Agency's general guidelines for how land areas may be used depending on which classification the land in the area has. This entails the different levels:
- KM means sensitive land use. Aggregates up to this level are counted as completely pure. Land that has the quality KM has no restrictions regarding area of use. All people can reside permanently within the area over a lifetime without risk of impact, and land that meets the KM requirements can be used for purposes including housing, cultivation and groundwater extraction.
- MKM means less sensitive land use. Land that has the quality MKM has some limitations regarding how it can be used. It can be used by people who are in the area during their working life, and by children and elderly people who are in the area temporarily. Groundwater at a distance of about 200 metres from the area and surface water are to be protected. Land with MKM contamination levels can, for example, be used for offices, industries and roads.
- FA means hazardous waste and refers to the contaminated aggregates reaching concentration limits for hazardous waste (Avfall Sverige 2007).