Most self-medication with marijuana remains illegal, and is grounds for discharge.

A federal court has ruled that a worker's self-administration of an illegal drug for pain relief was grounds for discharge under an employer's drug policy. The case highlights the problems employers will face as more workers receive the right to obtain medical marijuana to treat various disabling conditions.

Recent case: Michael worked as an engineer for PECO, the electric company that serves the Philadelphia region. The company has a zero-tolerance policy for illegal drug use and conducted...