Oklahoma Administrative Code
Title 325 - Oklahoma Horse Racing Commission
Chapter 45 - Prohibited Practices and Equine Testing
Section 325:45-1-29 - Environmental contaminants and substances of human use

(a) Environmental contaminants are either endogenous to the horse or can arise from plants traditionally grazed or harvested as equine feed or are present in equine feed because of contamination during the cultivation, processing, treatment, storage, or transportation phases.

(b) Substances of human use and addiction may be found in the horse due to its close association with humans.

(c) If the preponderance of evidence presented in the hearing shows that a positive test is the result of environmental contamination, including inadvertent exposure due to human drug use, or dietary intake, or is endogenous to the horse, those factors should be considered in mitigation of any disciplinary action taken against the affected trainer. Disciplinary action may only be taken if test sample results exceed the regulatory thresholds in version 4.0 of the ARCI Endogenous, Dietary, or Environmental Substances Schedule.