On 22 October 1966, north of Grundkallen (Sweden), the gas carrier Mundogas Oslo collided with the Finish vessel Sara. Following the collision, the Mundogas Oslo listed heavily and, 4 hours after the collision, was partially submerged, with its stern resting on the seafloor. That day, visibility was reduced to 300 metres due to heavy fog. The gas carrier, with 30 crew members onboard, was transporting 2,000 tonnes of liquid ammonia.
Adverse weather conditions (formation of ice, fog) made salvage attempts difficult.
After three and a half months, the bow sank in waters 64 metres deep in the Gulf of Bothnia.
The wreck is still sitting on the ocean floor. Studies have shown the presence of chronic leaks of ammonia from the tanks. According to certain estimations, 940 tonnes remain onboard. Since the accident, more than half of the cargo is believed to have been released into the sea.
To this day, this remains the only gas carrier to have sunk following a collision.
Name: Mundogas Oslo
Location: Gulf of Bothnia, Finland/Sweden
Accident area: north of Grundkallen
Cause of spill: collision
Product transported: ammonia
Quantity transported: 2,000 tonnes
Type of pollutant: ammonia
Quantity spilled: unknown
Ship type: gas tanker
Date built: 1963
Shipyard: Drammen Slip & Verk, Norway
Length: 91.2 m
Width: 14.66 m
Last update: May 2011