(PORT AUSTIN) -- The operator of a museum in Michigan's Thumb wants to keep a rare 19th century lighthouse lens. The federal government is suing Huron City Museums, saying it lacks approval to store and display an old lens that was used in the Pointe Aux Barques lighthouse on Lake Huron. The U.S. Coast Guard gave it to the city of Harbor Beach in 1970s under certain conditions. In 1987, Harbor Beach let Huron City Museums use it. The government says the lens is rarely available to the public and is stored in a building with no fire-suppression system, near Port Austin. In a recent court filing, the foundation that runs the museum asked a Bay City federal judge to dismiss the case.