AUGUSTA, Maine — Maine lawmakers have introduced two air quality testing bills.

One bill would require Maine's Department of Environmental Protection to notify municipalities of emissions violations.

The other would require that an independent, third party perform emissions testing.

The Portland Press Herald reports that the bills were introduced after South Portland officials were surprised to learn in March that a petroleum storage company there had been exceeding emissions limits for years.

The U.S. Environmental Protection agency had known since 2014.

States cannot require a federal agency to notify municipalities, but the bill applies to the Maine DEP.

DEP officials supported the notification bill at a legislative hearing Wednesday, but called the independent testing bill overly simplistic and unnecessary.

Union workers that conduct emissions testing said the bill insinuates their testing is unreliable.