brokenleg I doubt they'll find any marijuana in your system, but its a possibility.

Any findings that do occur won't result in you losing your job though, in order to fail a test you need to have a THC metabolite level that meets or exceeds 50mg/dL which you probably, like 95% do not meet. I know that even if you have some in your system, they'll let it slide if its lower then that, since clearly it means you've only experimented and are not a chronic user and it won't affect your mood/performance and stuff.