In Washington state the registration cycle for fertilizers begins on July 1 of each year. The Waste in Fertilizer Database will be updated approximately weekly as registrations are reviewed at the beginning of each cycle and as needed throughout the remainder of the year. 

The use of wastes (both solid and hazardous) in the manufacturing of fertilizers is a common practice that can provide a beneficial reuse alternative for materials that would otherwise be discarded. The beneficial properties of animal manure, for instance, as a fertilizer have been known for a very long time. Even some hazardous wastes, such as mining wastes and cement kiln dust, can provide micronutrient elements that are essential for plant growth.

However, some wastes used in fertilizer production also contain substances that are non-nutritive to plants and may present hazards to the environment or even people.

Historically, federal and state regulations have exempted certain hazardous wastes from regulation when those wastes are used in the manufacturing of fertilizer products. One such exemption applies to a hazardous waste from the steel industry called steel mill flue dust. Because of the benefits to plant growth, zinc containing steel mill flue dust can be used as an unregulated raw ingredient by fertilizer manufacturers. However, along with the zinc the steel mill wastes also contribute non-nutritive heavy metals such as cadmium and lead to fertilizers. Because of this, the Washington State Department of Ecology (Ecology) adopted a regulatory amendment in May 2000 which removed this exemption from the Dangerous Waste Regulations.