I agree with my colleague, you need to discuss this with an experienced immigration attorney.
J Charles Ferrari Eng & Nishimura 213.622.2255 The statement above is general in nature and does not constitute legal advice, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship. Answers on Avvo can only be general ones, as specific answers would require knowledge of all the facts. As such, they may or may not apply to the question.
The issue of drug use and abuse is a very touchy topic. Some certified civil surgeon are more quick to find abuse, rather than recreational or single use. How long ago did this happen? Have you thought of taking a drug test to see whether you will still have anything in your system?
In general, second hand smoke may not do as much damage. It is unclear whether and for how long this exposure will be found during a drug test. This is why I agree that you should seek an appointment or teleconference with a competent and experienced immigration attorney, who is familiar with your situtaion.
This is general information, not legal advice, and does not create an attorney client relationship.