Bay of Plenty Regional Council is investigating a spill of tall oil in Tauranga Harbour after a hose split while a ship was loading crude tall oil at the weekend.

Tall oil, a liquid by-product of pine pulp manufacture, was being pumped on board the tanker Stolt Span when a hose connecting the vessel to the terminal split, spilling the tall oil over the ship's deck shortly before midnight Saturday.

An amount of tall oil spilled over a ship's decks into the harbour when a hose split at the weekend.

'Most of the spill ended up on the deck of the vessel but some discharged over the side and into the water,” says Regional Council Pollution Prevention Team Leader Stephen Mellor.

Loading was being monitored, so the pumps were stopped in seconds. Crew and bulk storage staff immediately started cleaning up the spill to prevent any further discharge into the harbour.

'Bulk storage estimate between 100 – 200 litres of the (tall oil) rosin was released, however most of this ended up on the vessel and was able to be contained,” says Stephen.

'The amount of rosin that reached the marine environment was minimal, and the effects on the environment were minor.”

The pipe that split is pressure tested every six months. It will be returned to the manufacturer for tests to try find out the cause of the split.

The tall oil rosin is readily bio-degradable but very toxic for fish. All materials used during the clean-up from the Mount Maunganui wharf were disposed of safely. Regional Council staff checked for any remains of the spill in the area at daylight, and none was found.

'We take these incidents seriously. These hoses should be virtually failsafe and we need to know what went wrong,” says Stephen.

The Stolt Span sailed for Auckland at 11.55am on Sunday.