USDA

The certificate is given after an evaluation of product’s features and a final and definitive test is made to verify its biobased content. This test is called ASTM D6866 and calculates the level of biobased or renewable material contained in a product. It measures organic biobased carbon versus total carbon.
A percentage of biobased material equal to 69% says that, out of the total carbon in the product, 69% is biobased while 31% derives from petrol.