Oil slick stretching 200km seen near Chios Lion tanker after Houthi attack in Red Sea

Houthi militias have blockaded the Red Sea since November

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An oil slick more than 200km long has been spotted near an oil tanker struck by Houthi explosive drone boats in the Red Sea, satellite images revealed on Wednesday.

The Chios Lion, a Liberia-flagged tanker carrying a cargo of crude oil, was shown sustaining catastrophic damage as explosive drone boats rammed into its side in a video released by the group on Tuesday evening.

The attack was part of a swarm of strikes by the Houthis on the vessel and another ship sailing about 185km north-west of Yemen’s port city of Hodeidah. The Conflict and Environment Observatory, an environmental NGO, said the oil slick was 220km long.

Initial reports suggested the Chios Lion had weathered the initial attack with minimal damage.

“While originally headed south, following the attack the vessel turned around and back north out of the threat area to further assess damage and investigate potential oil spillage,” said the Joint Maritime Information Centre, a press office for the international coalition trying to safeguard the waterway and counter Houthi attacks.

It said the captain and crew were safe.

Wim Zwijnenburg, an expert on the environmental impact of conflict, said the spill will “likely cause the biggest impact from coastal pollution as the oil does not dilute easily, thus affecting the marine life on the shore”.

The Red Sea, a transit point for about 12 per cent of the world's maritime trade, is home to unique coral reefs.

“The area is facing frequent pollution from marine traffic passing through, including dumping of wastewater and attacks like these just add to an accumulation of pollutants in a fragile ecosystem,” Mr Zwijnenburg told The National.

“Usually ecosystems are pretty resilient, but these kind of mass pollution events are not helping."

While the spill stretches for many kilometres, it remains unclear exactly how much oil has leaked. Shipping data says the Chios Lion is 243 metres long, which places it in the Aframax category of oil tankers.

These vessels are much smaller than the largest oil tankers in the Ultra Large class, which can carry up to 3.7 million barrels of oil, but they can still hold between 500,000 and 700,000 barrels of crude.

Dean Mikkelsen, a security consultant focused on the region, said the vessel was probably double-hulled, based on information from when it was built, 14 years ago.

Double-hulled tankers were introduced in the early 1990s following a series of international treaties in the wake of the Exxon Valdez oil spill disaster, and have become an increasingly common feature on such carriers.

But they are designed to minimise the impact of tankers running aground, or colliding with other ships, rather than explosive attacks.

Houthi footage of the attack shows blazing oil spilling across the water.

An explosion on the Chios Lion oil tanker after it was attacked in the Red Sea off Yemen by Houthi rebels. EPA

The current Houthi campaign, focused on the Red Sea and Gulf of Aden, started in November and is taking a heavy toll on global commerce.

On Wednesday, a major international company said rebel group's attacks had disrupted its shipping via the Red Sea to its entire ocean network.

AP Moller-Maersk said in a statement: “The cascading impact of these disruptions extends beyond the primary affected routes, causing congestion at alternative routes and trans-shipment hubs essential for trade with Far East Asia, West Central Asia, and Europe.”

Maersk and other shipping companies have diverted vessels around Africa's Cape of Good Hope since December to avoid the Red Sea, with the longer voyage times pushing freight rates higher.

Asian exports are more affected by the situation than Asian imports, Maersk said, adding that this is primarily due to Asian countries being major global exporters.

Maersk said ocean cargo demand remains robust globally, with air freight, including a sea-air solution being used as an alternative where time-sensitive goods need to be moved quickly.