There’s an excellent article on the Contador doping situation on Sports Illustrated’s on-line site. Apparently there was more than just Clenbuterol found in Contador’s samples; they also detected “plasticizers” which are used to improve the suppleness of blood bags used in transfusions. Transfusions are every bit as illegal as EPO or any other banned drug, but there is not as yet a limit to how much “plastic” you’re allowed to have in your body (because they’re still working out standards and tests). What isn’t asked & answered in the article is whether such materials are used for the bags used to rehydrate cyclists (saline solution), which, as far as I know, is completely legal. [I've since learned that using IVs for rehydration was made illegal around 2007, with exceptions made only for those deemed medically required and must be done with a doctor present. It's also come out that the "plasticizers" would be found in bags used for saline IVs as well, not just blood bags. In the end, it means that finding plasticizers in any current doping sample is going to get someone in a lot of trouble.]
At this point, I’m no longer of the opinion that Contador is innocent simply because the amounts of Clenbuterol are so low, as another explanation is that he had a blood transfusion, using his own blood (that’s what you do so it’s not detected), and when that blood was drawn from him at an earlier time, he had been using Clenbuterol… and so contaminated himself. That’s just one possibility and doesn’t negate others. He may yet be an innocent victim, but hopefully not in the same manner as many other Spanish cyclists of the past, who have turned out to be part of a wide system of abuse that their government has looked the other way from (Operation Puerto).
Note: I had to disable comments on this piece because it’s attracting a zillion robotic spam zombies. Probably the references to drugs. Sigh.