Portage Mayor John Cannon said his police and fire departments want to close a city-managed lakefront pavilion that many people use to enter Indiana Dunes National Park.

The National Park Service says the controlled fires promote the park's unique ecosystems that include prairies, marshes and dune-lined beaches.

Since Indiana Dunes became a national park in February, its visitor center has seen more people than it has in any of the past eight years.

So far this year, the parks visitor center saw more people than it has in any of the past eight years and the year isnt over. June and July visitor numbers alone have doubled since last year.

The agency says three consecutive days of tests have been positive, including two days with no detection of cyanide.

The spill is still under investigation and the Indiana Department of Environmental Management will lead the effort.

About 15,000 acres of the Indiana Dunes were redesignated from a national lakeshore to a national park in February.

The ceremonial ribbon cutting for the Indiana Dunes National Park is set for Tuesday at the park's Miller Woods section on its western edge in Gary.

Indiana lawmakers have proposed making the lakeshore a National Park for years.