The U.S. Air Force has begun looking into Elon Musk apparently smoking weed on a podcast, a source at the military branch told CNBC on Friday.
Musk's SpaceX provides services for the Air Force, with multiple high-value contracts. Marijuana use is prohibited for someone with a government security clearance, Fox Business reported, and is the central issue in the Air Force's inquiry.
SpaceX and the Air Force did not immediately respond to CNBC requests for comment.
Late Thursday, Musk smoked marijuana and sipped whiskey during an appearance on Joe Rogan's podcast — fueling concerns about his recreational drug use. He discussed a wide range of topics including his tweeting behavior, his Boring Co.'s flamethrowers, and "neuralink" devices that could connect brains to computers.
The weed could be the smoking gun showing Musk violated his company's policy. One could argue Musk was representing Tesla as its CEO during the interview. By imbibing alcohol and marijuana, he was "under the influence" while at work.
Some states like California, where Rogan's podcast is recorded, have legalized the plant for recreational use. However, marijuana is still illegal according to U.S. federal law. U.S. Attorney General Jeff Sessions rolled back President Barack Obama-era policies in January that previously dictated the Justice Department would not pursue cases against those who violated federal marijuana laws in states where pot had been legalized.
This isn't the first time there's been concern about Musk's drug use. Tesla board members have also raised concerns over Musk's consumption of recreational and prescription drugs, according to The New York Times. In particular, sources told the publication that Musk's use of sleeping aid Ambien may be having a negative effect, causing him to ramble on Twitter.
– CNBC's Michelle Castillo contributed to this report.