Do a search on reddit (lots of pot smokers over there) on how long pot takes to clear your system or if there is anything you can do to accelerate the process.

Do a search on reddit (lots of pot smokers over there) on how long pot takes to clear your system or if there is anything you can do to accelerate the process. You might already be safe. If you are still in the detectable time period accept the job but say you can't report till X date because you have some personal matters to tend to where X is long enough to test negative. If this is not feasible talk to your hiring manager (i.e. not HR) and explain that you don't normally smoke pot but had a few puffs (and didn't inhale just like a former President) during some recent graduation parties and that it is legal in your state and maybe the test can be delayed or you can retake it in a month if it comes up positive. If your manager has any company "juice" he can get you past this hurdle. Ideally you want to test negative so its not in your permanent record.