About a year ago Thomas Hauser (one of the better boxing reporters and the guy leading the boxing press' campaign against PED abuse) reported the story that Mayweather had failed three USDA drug tests but each one had been hushed up by an "inadvertent use exemption"; essentially USDA can quash any A sample positive drug tests and not require the B sample to also be tested by stating that they believe the failure came about due to inadvertent use. As the B sample has not been found positive they then can't publicise it and it doesn't go down a positive test. The entire thing is hushed up and few people know about it outside rumours. Gabriel Montoya was also informed of this from a separate source.
What gives the story slightly more weight is that during the Mayweather/Pacquaio lawsuit over PED use the Mayweather side went from snarling defiance to desperately settling as soon as Pacquiao's side started the discovery process; including asking for documents relating to the rumour. Mayweather's side originally tried to squash those discovery documents and when that was thrown out, basically gave up, knelt down and gave Pac's side whatever they wanted.
Unfortunately Golden Boy got the story buried through legal threats; a website like MaxBoxing wouldn't be able to fund a legal defence if they were sued and I doubt their insurer (legal expenses or otherwise) would be happy to carry the risk. What makes it even more unfortunate is that as well as the stuff about Mayweather there was some concrete things about the pretty ludicrous relationship between VADA, USDA, promoters and the state athletic commissions, specifically with how they all interacted and dealt with the farces around Peterson, Berto and Morales all testing positive.
