How rawhide chews are made,
Producing rawhide begins with the splitting of an animal hide, usually from cattle. The top grain is generally tanned and made into leather products, while the inner portion, in its “raw” state, goes to the dogs. Removing the hair from hides often involves a highly toxic recipe: sodium sulphide liming. A standard practice is to procure rawhide in the “split lime state” as by-products from tanneries, facilities that top the list of U.S. Superfund sites. In the post-tannery stage, hides are washed and whitened using a solution of hydrogen peroxide. And that’s just one step.
Other poisonous residues that may show up in rawhide include arsenic and formaldehyde. Even dog skin is a possibility. An ongoing investigation of the fur trade by Humane Society International, an arm of the HSUS, resulted in
this information, as listed on their website: “In a particularly grisly twist, the skins of brutally slaughtered dogs in Thailand are mixed with other bits of skin to produce rawhide chew toys for pet dogs. Manufacturers told investigators that these chew toys are regularly exported to and sold in U.S. stores.”