Cargo ship hit by Houthis sinks, spilling oil and fertilizer into Red Sea

Food, drinking water and marine life are at risk after a cargo ship attacked by Yemen’s Houthi rebels spilled oil and fertilizer into the Red Sea.

The U.S. military’s Central Command, which oversees the Middle East, said early Sunday the Rubymar, a Belize-flagged vessel carrying 21,000 metric tons of ammonium phosphate sulfate fertilizer, sank at 2:15 a.m. local time Saturday.

The ship was struck by a Houthi anti-ship ballistic missile on Feb. 18 in the Bab el-Mandeb Strait, a waterway linking the Red Sea and the Gulf of Aden, and had been drifting northward after taking on water. Before plunging, the vessel had already been leaking heavy fuel that triggered an oil slick through the waterway.

“It’s really devastating,” said David Rehkopf, associate professor of epidemiology and public health at Stanford University in California.

Rehkopf co-authored a study about a potential Red Sea oil spill in 2021, when the FSO Safer oil tanker carrying millions of barrels of oil was decaying and in danger of spilling. Researchers found a spill would have “catastrophic” public health ramifications for residents in Yemen, Saudi Arabia and Eritrea.

Rehkopf is concerned about potential harm to marine life, which many residents rely on for food, as well as drinking water, given Saudi Arabia relies on desalination plants that filter sea water.

Spill could have ‘implications for the health of millions’

“Worst-case scenario is that there could be implications for the health of millions of people from pollution, and food supply and water supply effects,” Rehkopf said.

“This would be bad anywhere. I mean, if this occurred off the coast of Florida, it would be bad. But it’s exponentially worse because of the difficulties that are already going on for folks there.”

The Rubymar could leak 7,000 barrels, which is only a fraction of the oil carried by the Safer until its cargo was successfully transferred to another vessel last year. But that is still significantly more oil than was spilled by the Wakashio, a Japanese ship that wrecked near Mauritius in 2020, causing millions of dollars in damages and harming the livelihood of thousands of fishermen.

Ahmed Awad Bin Mubarak, the prime minister of Yemen’s internationally recognized government, called the Rubymar’s sinking “an unprecedented environmental disaster.”

“It’s a new disaster for our country and our people,” he wrote on X, formerly Twitter. “Every day, we pay for the Houthi militia’s adventures, which were not stopped at plunging Yemen into the coup disaster and war.”

U.S. Central Command has warned in recent days of an “environmental disaster” in the making.

Fish could become ‘inedible,’ researcher says

The Houthi rebels have repeatedly targeted ships in the Red Sea, a critical waterway for energy shipments heading to Europe, since November in protest of Israel’s attacks on Gaza.

The Red Sea is a vital source of food, especially in Yemen, where fishing was the second-largest export after oil before the current civil war between the Houthis and Yemen’s Sunni government.

“The most direct effect is one of tainting or contamination, which means that the fish become inedible,” said Peter Hodson, an oil spill expert and professor emeritus with Queens University’s School of Environmental Studies in Kingston, Ont.

“The impacts are ultimately on a failure to reproduce, or a lower reproduction rate because fewer embryos and larvae survive.”

Drinking water safety is of particular concern for Saudi Arabia, which for decades has been building the world’s largest network of desalination plants. Cities like Jeddah rely on the facilities for almost all of their drinking water.

“If (oil) got into the intakes it would certainly start to affect the whole desalination process,” Hodson said. “You might end up having to either shut down the purification process, or risk heavy damage that would completely destroy the desalination plant.”

Fertilizer ‘could be the worst component’

It is difficult to gauge the risk from the fertilizer that the U.S. military’s Central Command and port authorities in Djibouti, adjacent to where the Rubymar sank, said the ship was transporting.

Fertilizer can fuel the proliferation of algae blooms, resulting in the loss of oxygen, asphyxiation of marine life and the creation of so-called “dead zones.”

Hodson said the effect will depend on how badly the ship has broken, which will determine how quickly the toxins spill out.

“The fertilizer could be the worst component of all this, but it really depends on how intact the ship is,” he said.

The Red Sea is home to some of the world’s most colourful and extensive coral reefs, which are also at risk. Several are major tourist draws and increasingly a subject of great scientific research, owing to their apparent resilience to warming seawater temperatures.

Concerns raised about future spills

Ian Ralby, founder of maritime security firm I.R. Consilium, told the Associated Press that the Red Sea’s unique circular water patterns aggravate these concerns. The patterns operate essentially as a giant lagoon, he said, with water moving north toward the Suez Canal during winter and outward to the Gulf of Aden in summer.

“What spills in the Red Sea, stays in the Red Sea,” he said.

Ralby said he worries that even if this spill is manageable, there could be bigger disasters to come.

He said most container ships stopped using the Red Sea shipping lanes since the Houthis began targeting ships in the area. What remains, he said, are poorly maintained vessels, oil tankers and bulk carriers that pose far greater environmental risks.

“With fewer and fewer container ships to target, the odds of another spill with massive environmental impact has increased enormously,” Ralby said.