Nate Diaz could be in some hot water with USADA.

Diaz might be facing a UFC anti-doping policy potential violation for vaping cannabis at the UFC post-fight press conference Saturday night in Las Vegas, MMA Fighting has learned. Diaz was vaping on the dais and, when asked, said it was CBD, or cannibidiol oil.

"It's CBD," Diaz said after his majority decision loss to Conor McGregor. "It helps with the healing process and inflammation, stuff like that. So you want to get these for before and after the fights, training. It'll make your life a better place."

Cannibidiol is one of 113 active cannabinoids in cannabis. Cannabinoids are banned in-competition by the World Anti-Doping Agency (WADA) Code over a certain threshold and USADA uses WADA's prohibited substance list. In competition is considered the six hours before and the six hours after a fight. Diaz's appearance doing post-fight media was within that timeframe.

"I can confirm that USADA is aware of the situation and is currently gathering information in order to determine the next appropriate steps," USADA spokesperson Ryan Madden told MMA Fighting in a statement.

Cannabis is considered a "specified substance" by the UFC anti-doping policy. In other words, it's not an anabolic or hormonal agent, but it is still prohibited in certain cases, like in-competition. An athlete violating the policy for a specified substance can face a suspension of up to one year, according to Article 10.2.2.

USADA suspended Diego Brandao for nine months earlier this year for testing positive for marijuana metabolites in a fight-night drug test. Depending on circumstances, USADA can give cannabis users in-competition anywhere from a public-warning sanction to a one-year suspension, depending on the circumstances.

A drug test must have more than 150 ng/ml of marijuana metabolites to be considered positive. In this case, Diaz's fight-night drug tests have not returned yet, so no one knows if he tested positive or not. Diaz was tested before he got to the press conference.

USADA could consider him saying he was vaping CBD at the press conference as admitted use, which has the same sanction length as a positive test.

The Nevada Athletic Commission (NAC) also has jurisdiction on Diaz, because the situation happened in relation to his fight with McGregor at UFC 202 in Las Vegas. NAC executive director Bob Bennett did not respond to a request for comment.

A rep for Diaz could not be reached Monday afternoon.

Diaz has never failed a drug test in his MMA career. His brother Nick Diaz has three marijuana offenses in Nevada, including an 18-month suspension and $100,000 fine he was hit with last year. Nick Diaz is still currently under suspension by the NAC because he still owes $75,000 of that fine.

CBD has been used to treat epilepsy and schizophrenia. Studies have shown that it has fewer side effects than THC and does not cause any psychoactivity.

According to USADA, marijuana and its metabolites are prohibited in-competition because of potential performance-enhancing elements, a potential health risk to athletes and it violates the spirit of the sport.