Two oil slicks have appeared in Iranian waters as attacks on tankers and other vessels during the conflict involving Iran and the US raise concerns about environmental damage in the Gulf. Satellite imagery and video verified by Reuters show one slick off Qeshm Island, near the Strait of Hormuz, and another near Sirri Island in the Gulf.

The developments come as a separate and much larger oil spill continues to spread off the coast of Oman. That spill involves the Caroline Bezengi, a tanker carrying Russian crude which ran aground near Oman’s Hallaniyat Islands in June. It has not been linked to the conflict.

Oil Slick Reaches Qeshm Island

One of the slicks was detected off the southern tip of Qeshm Island, a large island near Iran’s coast. Satellite images from the Copernicus Sentinel-2 programme showed the slick on 10 August. Environmental open-source researcher Wim Zwijnenburg said the darker sections appeared consistent with heavy fuel oil, while a lighter, diluted slick extended for about 160km.

A video posted on 11 August and verified by Reuters showed dark, bubbling liquid washing ashore at Suza on Qeshm Island, contrasting with the surrounding turquoise water.

John Amos, chief executive of SkyTruth, which uses satellite imagery to monitor oil spills, described it as a “major incident”. “This is the biggest one that I’ve seen in recent months, really since the conflict between Iran and the US began,” he said.

Iran’s Foreign Ministry spokesperson Esmaeil Baghaei said preliminary evidence “indicates a foreign bulk carrier as the source”. The ministry said oil pollution had reached Qeshm Island and called for those responsible to compensate Iran.

Iranian environmental officials said clean-up operations had largely cleared the slick by Wednesday evening, although monitoring was continuing.

Baghaei said restoring the marine ecosystem of the Strait of Hormuz, the Persian Gulf and the Gulf of Oman should form part of any future arrangements governing the waterway. “Restoring the marine ecosystem of the Strait of Hormuz, the Persian Gulf and the Sea of Oman, and preventing further pollution, must be part of any future management arrangements for the Strait of Hormuz,” he said. “All parties that benefit from commercial shipping in this waterway have a legal and moral responsibility to address the environmental damage.”

Vessel Attacked Near Strait of Hormuz

The Qeshm Island slick may have originated from the Minoan Pioneer, a Liberia-flagged dry bulk carrier, according to Samir Madani, co-founder of the monitoring service TankerTrackers.com.

The vessel was hit by an unidentified projectile near Oman on 3 August while sailing through the Strait of Hormuz in what maritime security sources described as a suspected Iranian attack. One seafarer was reported missing.

A maritime security source told Reuters that the same leak was likely responsible for pollution reaching Qeshm Island.

A source involved in salvage operations said a tugboat sent to secure the Minoan Pioneer had been unable to approach the vessel because of difficulties obtaining permission from Iranian authorities.

Brian Barnes, a satellite oceanographer and research assistant professor at the University of South Florida, said the conflict had made it more difficult to assess and clean up oil spills. “The longer that the oil is leaking into an environment, the more it can spread out and cause damage to ecosystems, coastlines,” he said.

A second slick was detected near Sirri Island, about 100km south-west of Qeshm. The island is home to some Iranian offshore oil and gas production.

Satellite imagery of Sirri Island was captured on 13 August.

Much Larger Spill Off Oman

Meanwhile, a separate environmental crisis is developing about 500km south-east of Qeshm Island. The Caroline Bezengi, a Suezmax tanker carrying about one million barrels of Russian crude, has been leaking since running aground near the Hallaniyat Islands off Oman’s Dhofar coast in June.

The vessel had left Russia’s Black Sea port of Novorossiysk in April and was reportedly hit by an explosion off Yemen on 8 June. Its crew was evacuated without injury before the tanker grounded on rocks near Jazirat Al Qibliyyah.

The vessel has been sanctioned by the EU and UK for transporting Russian crude. Its registered owner and operator are both based in China.

The oil slick has expanded rapidly. Satellite analysis cited by Reuters estimated that it had grown from about 45 sq km on 26 July to more than 2,000 sq km by Wednesday.

Omani authorities estimated the slick at about 390 sq km on Monday.

Oil has reached beaches at Ras Madrakah on the Omani mainland, affecting up to 40km of coastline. The International Maritime Organization confirmed that the oil had reached the shore on Wednesday.

The Caroline Bezengi incident is separate from the oil pollution reported around Qeshm Island and has not been linked to the Iran-US conflict.