Combustion is also used to destroy (incinerate) waste, both nonhazardous and hazardous. Guidelines for the disposal of nonhazardous solid waste includes the banning of open dumping. Biomass is all solid, nonhazardous, cellulosic material taken from forested areas. Also, the lack of immediate human toxicity does not mean the substance is environmentally nonhazardous. Abietic acid is considered a "nonhazardous natural substance" in tall oil. The virgin soil method has the advantages of being relatively inexpensive, very effective and nonhazardous.