Hi Jimmy --
Drug testing is done for a lot of different types of reasons. Has your Company just now implemented a drug-free workplace policy? If the policy has always been in place, how was it administered before? Do you have a written policy on drug testing? When do you drug test? Upon hire? Reasonable suspicion? Accidents? Random? Some or all of those? Others?
Here is a blurb from http://www.uschamber.com/sb/business/P98/P98_05_1075_FL.asp
Florida's drug-testing law is contained within its workers' compensation law — a law covering employers of four or more, except in the construction industry where the law covers employers of one or more. Under the law employers may voluntarily implement drug-free workplace programs designed to lessen the frequency and severity of work-related injuries. If an employer implements a drug-free workplace program that includes notice, education and testing for drugs and alcohol following the rules for testing developed by the Workers' Compensation Division, the employer may require that an employee submit to a test for the presence of drugs or alcohol and, if a drug or alcohol is found to be present in the employee's system at (or above) a level prescribed by law, the employee may be terminated and forfeits eligibility for medical and indemnity benefits. In addition, the employer is eligible for reduced workers' compensation rates.
To qualify for reduced rates, an employer's policy must provide for testing of all job applicants, reasonable suspicion drug tests, and follow-up-tests for those participating in employee assistance programs unless the employee voluntarily entered the program. It may also provide for routine fitness-for-duty medical exams, including drug testing. A private employer may conduct random testing, or any other lawful testing, of employees for drugs.
As with many fairness oriented things, your feelings about a person's drug use is probably irrelevent. At the minimum, you must follow what your policy states. If you don't have a policy, you need to get one put together that complies with Florida law. Whatever is meant by "notification" and "education" would be critical points. You will also want to find out about what to do in the event of a person found to have a legal amount of a legally prescribed drug that may impair them and, because of their job duties, create a safety hazard.