Iran's environmental official said the spill near Kharg Island was caused by a non‑Iranian tanker dumping waste water, not a pipeline leak.
Satellite imagery from Copernicus Sentinel‑1,‑2,‑3 captured between May 6‑8 showed a grey‑white slick covering square kilometres west of the 8‑km long island.
Vice‑President Shina Ansari confirmed no pipeline leaks, saying monitoring showed the spill came from ballast water discharge of a foreign tanker.
Analyst Louis Goddard said the slick appears to be an oil spill since the U.S.–Israel war with Iran began 70 days ago.