Until the scope of employer rights and liabilities is more clearly delineated, the most conservative approach for an employer to take in dealing with employee substance abuse is to justify adverse employment decisions on the basis of job performance rather than on the violation of rules regarding drug or alcohol abuse. Those determined to pursue the latter course, however, should be aware of the legal obstructions. These include the possible requirement that any drug testing program be encompassed in a collective bargaining agreement; State common law causes of action protecting unorganized employees; a possible legal requirement to treat alcohol and drug addiction as handicaps, such that related employer decisions must comply with antidiscrimination laws; privacy or defamation claims; and other discrimination issues. Relevant cases are cited for each of the aforementioned legal concerns.