What are some of the reason labor unions are formed?

The major importance of a labor union is to organize the workers in order to make available a organization to negotiate a collective bargaining agreement with the managment. This agreement would cover such things as a safe place to work, a decent wage agreed upon between management and labor, and that both sides uphold any bargaining agreement that has been approved. Depending upon the business and economic conditions, health insurance, vacations, retirement plans, and work breaks can also be negotiated into an agreement. There usually is means for either side to settle issues (grievances) that might arise.