http://www.ncbi.nlm.nih.gov/pubmed/18563865?dopt=AbstractPlus I knew this was a potential problem. But this seems worse than I would have expected it to be. 15% seems pretty high. I also wonder how much of the "cross-contamination" isn't actually contamination, but actually done on purpose. I wonder if athletes would test positive for steroids when using the contaminated supplements. Do you think the contamination is high enough to put someone over the levels they test for?