Renewable fuel producers using used cooking oils or animal wastes as feedstocks are required under 40 CFR 80.1454(d)(3) to obtain from their feedstock supplier, and maintain in their records, documents which certify that the feedstock meets the definition of renewable biomass, describe the feedstock, and identify the process that was used to generate the feedstock.

For example, a renewable fuel producer could maintain as a record a contract with a feedstock supplier that states that the supplier will provide the producer with a certain volume of chicken fat that meets the definition of renewable biomass because it is an animal waste or byproduct, and that it was produced as a by-product of the chicken rendering process.