The Horseracing Integrity and Welfare Unit has withdrawn cases it had previously been pursuing against the trainers Keri Brion and R. McLane Hendriks for positives in horses they trained for a metabolite of cocaine, the organization announced on Friday. Both Brion and Hendriks had their provisional suspensions lifted in October after HIWU acknowledged that it would be reviewing their cases. Both trainers had argued that the positives stemmed from environmental contamination and denied that the horses had been deliberately administered cocaine, a popular but illegal recreational drug. :: Bet with the Best! Get FREE All-Access PPs and Weekly Cashback when you wager on DRF Bets. Brion, a former assistant to Jonathan Sheppard, and Hendriks, who is based at Parx, were both facing a two-year suspension. HIWU was treating the cases as “adverse analytical findings,” which requires the organization to investigate potential sources of environmental contamination. In a release, HIWU said that the review resulted in the organization adopting a new standard for testing levels of the metabolite, benzoylecgonine, in blood. Under those new standards, the concentrations of the metabolite was below the threshold that would result in a violation in both cases, HIWU said. :: Want to learn more about handicapping and wagering? Check out DRF's Handicapping 101 and Wagering 101 pages.