Conor McGregor, left, beat Nate Diaz via majority decision at their second faceoff Aug. 20. (Steve Marcus/Getty Images)

UFC star Nate Diaz will not be sanctioned for ingesting a prohibited substance via a vape pen during his UFC 202 post-fight news conference in August. Instead, the U.S. Anti-Doping Agency, which oversees and administers UFC’s strict drug policy, issued a “public warning” to the 31-year-old Thursday.

At the Aug. 20 news conference, the Stockton, Calif., native identified the substance as cannibidiol, a non-psychoactive cannabinoid derived from marijuana that USADA prohibits the use of in-competition only. That’s defined as the window of time that begins six hours before the official weigh-in and ends six hours after the fight. Diaz, who explained the substance “helps with the healing process and inflammation,” claimed that when he ingested it that night, he had thought the in-competition window had ended, USADA explains in the release.

Additionally, USADA said Diaz’s in-competition urine and blood samples came back clean of all prohibited substances, including cannibidiol.

“Based on these circumstances, USADA determined that a public warning was an appropriate response to Diaz’s use of a specified substance during the in-competition period,” the agency said.

Diaz, who the USADA says “accepted” the warning, has not publicly commented on it.

The ruling follows that of the Nevada State Athletic Commission that oversaw UFC 202 in Las Vegas in August. In early September, NSAC also decided against penalizing Diaz for using the substance at the news conference.