One time Marijuana Use While Holding Public Trust Position, Interested in Position Requiring Top Secret Clearance

I have been a federal employee with a public trust clearance for the past 5 years. 18 months ago I visited friends in Colorado for a wedding and consumed a brownie containing THC. This is the first and only time I have consumed an illegal drug. I don’t have any justification for this lapse in judgment. My friends offered me the brownie, I knew marijuana was legal in Colorado but remained illegal federally and in the spur of the moment decided to try it once out of curiosity. I have not had any illegal drugs since and have no intention to do any illegal drugs in the future.

A position is opening at my agency with a top secret clearance that my supervisor has encouraged me to apply for. I am wondering what my chances of obtaining a top secret clearance would be given that I took an illegal drug while holding a public trust security clearance approximately 16 months ago. Thank you for your help!

You’re going to have a hard time . . .