On 6 September 1982, a Danish frigate, the HDMS Peder Skram, accidentally fired a Harpoon missile during maneuvers in the Kattegat. The missile traveled 34 kilometers at low level, severing several power lines before striking some trees after which it exploded. The fireball and subsequent shock wave destroyed four unoccupied summer cottages and damaged a further 130 buildings in the immediate vicinity. No human injury was reported.
Cause
A navy investigation into the matter concluded that a technical malfunction was the cause of the launch as it happened without the launch key being activated. The missile system had undergone maintenance and was in the process of being checked by an expert from the navy material command, who was later charged and convicted for negligence, though most charges were later dropped following a second investigation. McDonnell Douglas, the manufacturer of the missile later paid the Danish government a compensation, which covered all the damages made by the missile.