DENVER — A group wants to block the construction of trails and a visitor center at the Rocky Flats Wildlife Refuge, a former nuclear weapons facility.

The site is set to open to the public this summer when the U.S. Fish and Wildlife Service will open up internal trails for use. Phase two of the plan wouldn't happen until 2020, but it includes regional trail connections funded by a federal grant and a visitor center.

Opponents will take legal action and plan to file a complaint in court on Tuesday. They want to reverse that recent federal decision to build trails, a visitor center and ultimately open it up to the public.

This is not the first challenge Rocky Flats has faced. Several groups also filed suit last May in an attempt to block the site from opening to the public.

The groups involved in the legal action this time around include Rocky Mountain Peace & Justice Center, Candelas Glows, Rocky Flats Grows, Rocky Flats Right to Know, Rocky Flats Neighborhood Association, and Environmental Information Network.

Denver7 reached out to the U.S. Fish and Wildlife Service for comment on the pending legal action.