California state law allows the medical use of marijuana with a doctor's prescription. Marijuana use is still illegal under federal law. The California Supreme Court recently held that an employer acted lawfully when it fired an employee whose marijuana use was disclosed by a pre-employment drug test even though he was using the drug for medical reasons and under a doctor's supervision. Here's a link to the opinion, along with thoughts from some California-based employment law bloggers here, here, and here.
NJ has no medical use of marijuana law, so this development has no applicability to companies that confine their business to this state. Since many NJ-based companies now have operations in California, however, this decision will be important to them.