Satellite images captured between 6 and 8 May have revealed a large oil slick in the Persian Gulf near Iran's Kharg Island, the country's principal oil export terminal located off the southwestern Iranian coast. The dark patch, visible in imagery from the European Copernicus satellite programme, initially spread across more than 50 square kilometres. Monitoring firm Orbital EOS estimated that over 3,000 barrels of crude oil may have been discharged into the Gulf, prompting serious environmental concern in the region.

The cause and origin of the slick remain unclear. Several explanations have been put forward: recent military strikes in the region could have damaged Iranian oil infrastructure; a US naval blockade around the Strait of Hormuz — the narrow waterway connecting the Persian Gulf to the Arabian Sea — may have saturated Iranian storage capacity, placing strain on ageing facilities; or the leak could have originated from an older Iranian vessel used to store crude oil offshore. Iranian authorities, however, have pushed back against the most alarming scenarios. A member of parliament representing the coastal city of Bushehr attributed the slick to discharges from a European tanker, while the head of parliament's energy committee stated there was "no official report" confirming that any Iranian oil installation had leaked due to storage overflow, adding that production across the country's oil fields was continuing "without the slightest problem."

Environmental monitoring organisation the Conflict and Environment Observatory (CEOBS), drawing on more recent Copernicus imagery, reported that the slick had "significantly reduced" in size since the first images were taken. Nevertheless, the organisation cautioned that the slick's cause could not be conclusively determined from satellite data alone. "Although offshore infrastructure in the area could be a potential source, we are not able to identify a definitive point of origin or attribute the spill to a specific cause at this stage," said Leon Moreland of CEOBS.

The incident matters for several reasons. Kharg Island handles the vast majority of Iran's oil exports, making it a critical node in global energy supply chains. The Persian Gulf is also one of the world's most ecologically sensitive maritime environments, and even a contained spill of this scale can cause lasting damage to marine ecosystems. With the region already under pressure from geopolitical tensions, establishing the true origin of the slick — and preventing further pollution — will be closely watched by both environmental groups and international observers.