Mitsui OSK Lines, charterer of a capesize bulker that grounded on a reef off Mauritius last week, has joined the ongoing response to the casualty amid growing fears a major pollution incident is developing.

As earlier reported, Japan's Nagashiki Shipping is working with local authorities and salvage company Smit to try to contain the growing spill on the east of the island. The company is owner and manager of the grounded 203,000-dwt Wakashio (built 2007).

Protection and indemnity insurer Japan P&I Club is also involved in the casualty response.

Nagashiki earlier said the ship’s bunker tanks had been breached after a period of heavy weather.

The vessel has an estimated 4,000 tonnes of low sulphur fuel oil and diesel aboard. The stranded vessel is close to a marine park, exposed beaches and reefs.

MOL has been operating the vessel commercially on the spot market since it recently finished its long-term freight commitment to a Japanese steel mill.

The Wakashio was heading to Brazil from the Far East in ballast when it inexplicably hit the island.

In a statement, MOL said it regretted the incident. “MOL is fully aware of the incident and the regretful harm to the beautiful nature in Mauritius,” the company said.

Chief executive Junichiro Ikeda will lead an emergency response team set up at the company’s Tokyo headquarters.

The company has also dispatched personnel to the site of the disaster and has said it will offer whatever support is required to the ship’s owner.

“MOL will cooperate with related parties based on the advice from the authorities of Mauritius and Japan,” the company said.

“We hope the situation is brought to a safe and timely conclusion.”