Very early on the morning of September 28, 1983,
the tanker Sivand grounded on a jetty at the Immingham oil terminal
in the Humber Estuary.
Cargo tanks ruptured on impact,
and Nigerian Forcados Crude oil spilled into the Humber River estuary.
Nigerian Forcados crude oil has as API gravity of 29.7, and a pour point of -4 degrees F.
Approximately 48,000 barrels of the crude oil spilled into the estuary.
Oil impacted the north and south shores of the estuary late on September 28,
including the docks at Immingham and Grimsby, and beaches at Cleethorpes.
Easterly winds on September 30 pushed the oil up the Humber River as far as the River Trent.
The mudflats of the Blacktoft Sands Nature Reserve,
and the salt marshes of the River Ouse were oiled on September 30.
Of the oil spilled, it was estimated that 12,000 barrels evaporated,
16,000 barrels were chemically dispersed,
and the rest dispersed naturally, was carried out to sea, or came ashore.