Failed FBI polygraph, now received a DOJ job

[guy]

Last summer I failed an FBI polygraph because I made a post-polygraph admission about putting a pot pipe to my mouth and my answers to the drug questions were not within prescribed limits. I am currently in law school and recently I received a summer internship in a US Attorney's Office. The DOJ background check is for non-sensitive positions and only requires that I have not used drugs in the past year. The event in question took place more than one year ago and I have not done anything since. Do you think DOJ will care about the failed FBI polygraph? I am trying to find any US Code about restrictions on disclosure of polygraph results. Might they use this against me because it can be characterized as dishonest? I plan on fully disclosing this situation in my security papers, but I still worry they will deny me a clearance because of this.