Could I be drug tested after I’ve already been hired and worked a day?

Title says it all. I stopped smoking because I was in search for a job. I got one, they hired me and I’ve already gone through training, filled out forms, and even worked a full day. They made no mention of drug testing. Should I be in the clear to smoke again now?

usa jobs
usa jobs resume
usa hotel jobs
usajobs
usa jobs federal government
usa job in ksa
usa jobs
usa jobs login
usa jobs gov
usajobs.gov
www.usajobs.gov
usajobs.com
usajobs
usajobs.gov official