https://www.bbc.co.uk/sport/horse-racing/56521788 To save you reading it, a jockey has been banned for returning a positive test for cocaine 1000 times over the limit allowed. Surely in professional sport the limit is zero for all recreational drugs? Or am I missing something?
I believe there is a minute tolerance for certain drugs as they can show in tests when ingested inocennently, poppy seeds on a bread bun may return the tiniest showing on a test, but nowhere near the showing of someone who has taken opiates knowingly.