“One possible way (the drug got into the food) is through the use of contaminated ingredients,” Clean Label Project Executive Director Jaclyn Bowen explained in an email to the Miami Herald. “Rendering plants take slaughterhouse animal tissues and convert them into stable, usable materials like purified fats such as lard or tallow. This rendered material is then sourced by some pet food manufacturers and sold to consumers as wet and dry pet foods. It is possible that animals exposed to pentobarbital were included in the rendering process.”