DES MOINES, Iowa (AP) — Iowa’s largest teachers union has filed a lawsuit challenging a new law that eliminated most collective bargaining rights for public workers.

The announcement Tuesday by the Iowa State Education Association marks the second lawsuit by a union against the law, which took effect in February.

The association, which represents 34,000 school employees in the state, claims the law creates two classes of public sector employees, unfairly targets unions for collecting dues through payroll deductions and creates an unfair election system for unions.

The Davenport Education Association is a plaintiff in the lawsuit. The state of Iowa and members of the Iowa Public Employment Relations Board are listed as defendants.

The American Federation of State, County and Municipal Employees, Iowa Council 61, also filed a lawsuit in February challenging the law.