Most plastics take up to 400 years to break down; however, even though thes whits wing bin bags are made from combinations of polypropylene and polyethylene, they are designed to include 1-3% metal salt additives, rendering them biodegradable.  When exposed to heat, light or landfill conditions, they break down completely into water, CO² and a small amount of biomass - a process which takes around 18 months. This process leaves no toxic residue, and emits no methane. Dimensions: 590mm x 760mm, with a capacity of 50 litres.  Sold in rolls of 15.

For more in-depth information, click on this link: http://www.degradable.net/controlledlife-plastic/why-degradable/