Police in Florida have confirmed that a grenade launcher loaded with a live grenade was found among a collection of charitable donations left outside a Goodwill store.

The Bradenton Herald reports that shop workers in the city of Bradenton discovered the weapon in a shipment from a nearby store on Sunday (28 January). The donor is not known but an investigation was under way.

Manatee County Sheriff's Office said it had stored the grenade safely in a Hazmat (hazardous materials) locker and the launcher in the police property room.

Owning a grenade launcher is legal under federal US law, but it is illegal to use them to fire anything more explosive than a flare.

The launchers themselves are not considered by government agencies as destructive devices but the grenades and rockets used with them generally are.

News of the unusual find followed the discovery of dozens of grenades by a roadside in Maryland by someone collecting recyclables. Of the 38 found, nine were live. Nineteen had a fuse but no explosive filler and 10 were inert.

"The devices were determined to be hazardous and procedures were conducted immediately at the scene; in addition six devices were transported to a nearby County landfill where they were counter charged," the Maryland State Fire Marshal said.