(a) A court may not grant injunctive relief in a labor dispute: (1) if the plaintiff has failed to comply with each obligation imposed by law that is involved in the labor dispute; or (2) except as provided in subsection (b) of this section, if the plaintiff has failed to make every reasonable effort to settle the labor dispute: (i) by negotiation; or (ii) with the help of available dispute resolution mechanisms, governmental mediation, or voluntary arbitration. (b) If irreparable injury is threatened, a court may grant injunctive relief before another tribunal acts to settle the labor dispute.
Maryland Legal Code