I was the CFO for a construction company that had a little over a hundred employees. Our policy required pre-employment drug tests and random drug tests for those who worked in "safety sensitive" positions (which was pretty much everyone who worked on job sites).

Any job applicant who failed a pre-employment drug test would have their name and other information entered into the company database. Our HR department was required to check the database before contacting job applicants for an interview. The company did not share the database with any other companies or individuals.

For current employees who tested positive for the first time, they were required to attend a substance abuse counseling program (on company time) in order to maintain employment. They were then required to undergo weekly random screenings for 3 months. Any positive tests during that period would be cause for immediate dismissal.

When any other business contacted us to confirm a former employee's information, as a policy, we would only verify their period of employment and title. This applied to all employees - not just the ones who were fired because of drug abuse.