The tank vessel St. Peter departed Tumaco, Colombia on February 4, 1976 with 279,000 barrels of Orito crude.
On the evening of February 4, a fire broke out in the engine room
and the crew abandoned ship after unsuccessful attempts to extinguish the fire.
There were subsequent explosions on board the St. Peter
and the fire continued to burn until February 5 or February 6,
when the vessel sank in over 3,000 feet of water approximately 18 miles off Cabo Manglares, Colombia.
An Ecuadorian patrol boat returning to the site on February 6,
found only an oil slick approximately one square mile in area.
The sunken vessel released an initial burst of oil
and then continued to slowly leak oil for some time.
The vessel was known to be leaking oil nine months after the sinking.
The area affected by the spill covered a distance of over 200 miles,
from Buenaventura, Colombia in the north to Punta Galera, Ecuador in the south.
The predominant shorelines in the area were sandy beaches,
rocky shores, and estuarine areas with mangroves.
The heaviest oiling occurred in the area of Tumaco, Colombia
and portions of the shoreline to the south, near the border of Ecuador.
Orito crude is a light Columbian crude with an API of 35.5,
viscosity of 4.8 centistokes, and a pour point of 25 degrees F.
Oil released from the vessel moved in a northeasterly direction
and came ashore in Tumaco in Colombia, and Esmaraldas and Isla Gallo in Ecuador.