In some instances, animals euthanized at shelters or animal control agencies have been sent to meat rendering facilities[20][21][22] to be processed for use in cosmetics, fertilizer, gelatin, poultry feed, pharmaceuticals and pet food.[23] It was proposed that the presence of pentobarbital in dog food may have caused dogs to become less responsive to the drug when being euthanized.[24] However, a 2002 FDA study found no dog or cat DNA in the foods they tested, so it was theorized that the drug found in dog food came from euthanized cattle and horses. Furthermore, the level of the drug found in pet food was safe.[25]