The can linings that are used in Wysong canned pet foods are in compliance with the standards set by the FDA. The materials are approved for high temperature heat sterilization. The material films and adjuvants are either prior sanctioned, GRAS, subject to a FCN, or conform to FDA regulations. There have been tests conducted on certain BPA-free linings, particularly BADGE, but the results of these tests were inconclusive because a true scientific method was not employed. More information about BPA can be found on the FDA's and CMI (cancentral.com) Can Manufacture institute websites.
There are risks associated with any processed foods, and even unprocessed foods, if fed exclusively. If foods are given to animals on a rotational basis as part of an IV (intermittent and varied) diet with fresh fruits and vegetables and raw meats as we recommend, then any possible toxins from food ingredients or can linings won't have the chance to accumulate.
Please also see: Toxins: http://www.wysong.net/pet-health-and-nutrition/wysong-products-and-toxins.php.