The words “foreign substances” sound ominous. HSUS want you to associate those two words with “soring”. That is not true. A foreign substance can be anything. The rules say “nothing is allowed above the hoofs on a Tennessee Walking Horse. The USDA has taken that statement literally and anything, which includes particles as small as 1 PPM is deemed in violation of the rules. Some of the “stuff” found is related to fly spray, and other everyday substances used around a barn. They have even list cholesterol as a foreign substance, yet it is actually produced by the body and found in sweat. There has never been a case prosecuted on a finding of a caustic (soring) substance.
For an expanded document, click RELEASE – FS -Condensed 01 illustrated
In a video provided by Whatahorse TV you can see an illustration of the “one part per million” and the USDA and their lab explaining that there is no bottom threshold and that it is actually less than 1 part per million that they consider a positive finding of ANYTHING