World
Tanker Attacks Near Strait of Hormuz Raise Fears of Major Oil Spill Disaster
Escalating military strikes between the United States and Iran are increasingly playing out at sea, with both nations targeting oil tankers and vessels navigating the Strait of Hormuz, raising alarm over the potential for a catastrophic oil spill in the Gulf.
On September 8, US forces struck five Iranian oil tankers, an action that prompted Iran to launch a retaliatory attack on Jordan's Al-Azraq airbase. Three days earlier, on September 5, the US had also struck three Iranian tankers. According to US Central Command, that strike followed Iran firing ballistic missiles at a US aircraft carrier and a navy destroyer near the Strait.
Iran has said it targeted three oil tankers travelling through what it described as an "unauthorised route" through the Strait, along with three additional vessels linked to the US elsewhere.
The exchange of attacks has transformed Hormuz into a potential environmental hazard zone. With tankers carrying millions of barrels of crude oil and petroleum products passing through or waiting near the waterway, any successful strike could cause fires, sinkings, or a significant oil spill.
According to MarineTraffic data from September 7, 42 tankers were waiting to pass through the Strait of Hormuz, with hundreds of additional vessels stalled or moving slowly through the broader Gulf of Oman and Gulf region. Eighteen of the waiting tankers were carrying oil. Although the exact quantities aboard each vessel are unknown, their combined estimated capacity is 1.76 million cubic metres of oil and petroleum products — cargo that remains at risk should attacks on commercial shipping persist.
That volume equals roughly 11.1 million barrels of oil, or about 11 percent of global daily oil demand — enough to fill approximately 714 Olympic-sized swimming pools. A major strike or sinking involving such cargo could release millions of litres of oil into the Gulf, threatening coastlines, fisheries, and fragile marine ecosystems. Unlike spills on land, oil in open water can spread across vast distances, driven by currents and wind far from its original source.
On September 5, CENTCOM confirmed that US forces struck three Iranian crude-oil tankers: one near Kharg Island, Iran's primary oil-export hub; another close to Jask; and a third, unladen vessel in the Gulf of Oman after its crew was instructed to abandon ship. This marked a further escalation in attacks on regional oil shipping.
Since the war began, at least 75 ships have come under attack, resulting in at least 21 seafarer deaths. Two incidents have caused minor oil spills, while six have resulted in fires.
One spill already affecting Oman's coast originates from the tanker Caroline Bezengi, which ran aground about 22 nautical miles (41 kilometres) off Oman following a suspected explosion reported by its crew in early June. Reuters estimated the vessel was carrying 800,000 barrels of oil. Oman's Environment Authority has warned the spill could impact roughly 40 kilometres (25 miles) of coastline near Ras Madraka and Masirah Island.
Separately, on August 3, the Liberian-flagged bulk carrier Minoan Pioneer was struck by an unidentified projectile off Oman and caught fire. Satellite images from August 10 revealed a large oil slick near Qeshm Island, along with another near Sirri Island. Experts believe the Qeshm slick likely originated from the Minoan Pioneer, though this has not been independently confirmed.
Past conflicts offer a warning of the potential damage. During the 1991 Gulf War, retreating Iraqi forces set Kuwaiti oil wells ablaze, causing fires that burned for months and released millions of gallons of oil into the northern Gulf. More than 770 kilometres of coastline, stretching from southern Kuwait to Abu Ali Island in Saudi Arabia, were coated in oil and tar, devastating local marine ecosystems for decades.
Thirty-five years later, the current US-Iran conflict again threatens the region's delicate marine environment. The Gulf hosts resilient coral reefs, mangrove forests, seagrass beds, mudflats and salt marshes that thrive despite extreme heat and salinity. These habitats serve as critical feeding and breeding grounds for fish, turtles, dugongs and migratory birds, while also sustaining local fisheries and protecting coastlines. Because the Gulf has limited water exchange with the wider Indian Ocean, pollution poses an outsized threat to its ecosystems.
A University of South Florida study published in June found that satellite imagery showed oil spills in the Gulf and Strait of Hormuz were four times greater in March compared with the previous year, with researchers noting frequent oil leaks from vessels stranded in and around the Strait.
Dr Hussein Samh al Masroori, an associate professor at Sultan Qaboos University, told Al Jazeera that oil and petroleum hydrocarbons can directly harm fish, corals, plankton and other marine organisms, with fish eggs and larvae especially vulnerable. He noted that sensitive habitats such as coral reefs, mangroves, seagrass beds and coastal sediments can retain pollutants for extended periods, and that changes in water quality and food-web productivity can indirectly affect fish distribution and spawning patterns. For coastal fishing communities, this can mean reduced catches, higher costs and lost income.
Oil can also settle into sediments and coat beach sand and mud, as occurred during the 1991 Gulf oil spill.
Gulf countries depend heavily on desalination for water supply, serving a population of nearly 65 million. Iran also operates several desalination plants along its southern coast, some of which have been struck by US forces; roughly 15 million people live along Iran's coastline. Al Masroori explained that oil contamination near seawater intakes can degrade raw water quality, disrupt treatment processes and, in severe cases, force temporary shutdowns of operations. He noted that the actual risk depends on the spill's location, ocean currents, distance and depth of the water intake, and the treatment technology used, but that modern monitoring and treatment systems can substantially reduce these risks if contamination is detected early.