
Quoting
flyingron
Hal, that was almost certainly a test done by your employer in their drugs in the workplace program. While this is a requirement to get federal contracts, it doesn't necessarily require testing, nor is it directly related to any particular employee's security clearance. Indeed, I've read the requirements and had a successful program established that didn't involve any routine testing.
Not saying companies don't drug test, but the Feds do not require it as a condition of getting a clearance. We didn't drug test and I guarantee that we had people with clearances you've never heard of. Many of the government entities that we contracted to don't even exist publicly.
The key is, that the drug testing isn't the issue. Even in the military, the drug testing is potentially excusable. The point is that intentionally lying on a security clearance application is a much bigger issue.
The Medical MJ card is going to raise eyes if detected so you should disclose. You can explain that you've found other ways to get around the condition than (federally) illegal drugs.