Pesticides that can no longer be used for any purpose are dangerous toxic waste.
But it's not just pesticides that are dangerous.
Wherever pesticides are used, there are discarded pesticide containers. These old containers can be as dangerous as the pesticides themselves. In developing countries, they are often used to store food or water. FAO's Programme on the Prevention and Disposal of Obsolete Pesticides assists developing countries deal with these toxic containers.
Often stockpiles of old pesticides are poorly stored and toxic chemicals leak into the environment, turning potentially fertile soil into hazardous waste. The Programme also provides strategies for handling contaminated soil.