Decomposition, also called biodegradation, is the chemical breakdown of organic and other materials through the action of bacteria and other biological means. How long it takes for a material to decompose depends on the type of material and the method of degradation. The values given in the illustration above are only typical and may vary significantly depending on circumstances. There are extremely wide variations; for example, a paper towel may decompose in 2–4 weeks, and a plastic bag takes several thousand years to degrade and decompose completely.
Biodegradable products decompose easily with time and transform into natural substances without much effecting the environment. However, many products can take centuries or more to decompose completely, during which time they may pollute the environment with toxic elements.