DES MOINES, Iowa (AP) — A judge has dismissed a lawsuit by one of Iowa's largest public workers unions that challenged the state's new collective bargaining law.

The ruling Monday by District Court Chief Arthur Gamble concludes the law's new classification for public safety workers is rational. The American Federation of State, County and Municipal Employees, Iowa Council 61 argued in its lawsuit that the classification — which allowed some workers to keep bargaining over working conditions taken away for others — violated the state constitution.

AFSCME Council 61 President Danny Homan says in a statement the union is considering its legal options, including an appeal.

The decision comes after a separate judge dismissed a similar lawsuit filed by the state's largest teachers union. Iowa State Education Association says it's considering an appeal.