Define "recently."   

When I was in the military, there was no way in hell you would ever be granted a TS/SCI clearance if you admitted to smoking pot "recently" (last 7 years).   

In fact, as a DOD civilian holding a sensitive position that requires a TS/SCI clearance, I would think that you may be required to submit to random urinalysis testing.  Bottom line, if you ever pop positive on a random urinalysis in your new job, or admit to smoking dope last week with your friends, you can kiss that Top Secret clearance goodbye.  Actually, I believe you would be kissing your job adios also.

Anyone else out there know if I'm way off base?   

Kona

Vera,

When I had to go through the process of applying for a TS/SCI clearance, there was no polygraph, and no urinalysis.  I did have to fill out an SF-86 form (which is basically a personal history statement), and be interviewed by a Defense Investigative Service Agent.  The SF-86 is very long, and covers just about everything in your life (family, friends, foreign travel, foreign friends, finances, jobs, drug use, etc).  The process is long, and can take up to a year to complete.  My clearance took about 9 months to be granted.   

One thing the Defense Investigative Service (DIS) does that most police departments don't is to actually go out in the field and conduct face to face interviews with people in your past.  I was amazed to find out that they interviewed military friends, family members, next door neighbors from my childhood years, and people I hadn't talked to in years.  In my opinion, this type of background investigation beats the hell out of any worthless polygraph session.   

If you want the most current info on the entire process, you should talk to your security manager where you work.  You should be able to ask what type of events would be disqualifying for a TS/SCI clearance, and what will be required of you during the process.

Good luck.

Kona

Kona & Outraged -

Thank you for your replies.  I will talk to our security chief about requirements/procedures for this assignment.   
I'm aware that the TS/SCI takes about 6 months to complete and would prefer face-to-face investigations to polygraph.  This site has made me serously doubt the validity of polygraphs and I don't want my career path to be limited by one.
I'm strong enough to do the right thing but experienced enough to know that telling the absolute truth to strangers does not always serve the common good.
Consider me fully reformed.   

Thank you and good luck to all -
  Vera