City

The incident 

On 10th January 2016, the Russian cargo ship City ran aground on a breakwater outside the Japanese Port of Sakata (Yamagata Prefecture, Sea of Japan) with 17 crew members on board. The vessel was at anchor when the wind strengthened. It attempted to sail out to sea, before running aground. The ship sank quickly (on 18 January) and subsequently split in two then broke apart.
Approximately 120 tonnes of propulsion fuel oil (IFO 180 as well as diesel and lubricants) leaked from the ship. Under the influence of the waves and currents, the oil slick spread through the port waters, oiling many port structures, the banks of the Yutaka river – forming 30 cm-tall bands (2 to 4 mm thick) on each size of the river – and irrigation channels supplying water to adjacent rice paddies. At the time of the accident, while the rice paddies were left fallow and empty, some of the drainage channel gates had been left open. Oil carried via the drainage channels due to exceptionally high water levels stained the upper edges of the concrete channels bordering the rice paddies. In total, around 2 km of channels were affected.

Spill response

On-shore response was implemented with on-site assistance from the technical expert, ITOPF (International Tanker Owners Pollution Federation), appointed by the vessel’s P&I club, on site from 19 January. During the 8-week response, various techniques were implemented including:
- Recovery/scooping of the floating oil (viscous and relatively congealed) using nets;
- Manual recovery of stranded oil;
- Use of sorbents (pads, mats and snares), and
- Scraping of the thickest coatings on hard surfaces (port structures, concrete channel walls) followed by high pressure washing along 8 km of banks.

Following the incident, heavy and prolonged snowfall caused significant disruptions and delays in the progress of clean-up operations, as well as difficulties in accessing maps of the network of rice paddy irrigation channels (built in the 1950s, it took more than two weeks for responders to obtain detailed information).

It was crucial that clean-up operations be completed before the thaw, between the first and third week of March, to ensure that agricultural practices in the region were not affected by either the oil or the clean-up operations. This led to the use of more aggressive clean-up techniques than those usually implemented in rivers. Residual traces of oil along the riverbanks and the edges of the rice paddies were cleaned up using hot water and pressure washers, at the request of the authorities. In total, 8 km of concrete banks were cleaned up using this method. Despite the harsh weather conditions, clean-up operations were completed on schedule.
The vessel was subsequently demolished and removed by the salvage company.