Black rain fell on Iran's capital Tehran following US-Israeli strikes on oil facilities on 7 and 8 March. The strikes ignited fires that produced thick smoke, leading to health concerns among residents. Scientists warn of potential environmental and health risks from the polluted precipitation.
On the night of 7 March and into 8 March, US and Israeli forces targeted Iran's oil infrastructure for the first time since the conflict began over a week earlier. The attacks struck four oil storage facilities and an oil transfer centre in Tehran and the nearby Alborz province, sparking large fires. Thick black smoke filled the skies over northern Iran, blanketing the capital and depositing soot on streets, cars, and balconies.
Residents in Tehran, which had been enduring a prolonged drought, experienced thick black raindrops falling on roofs and streets. Local authorities issued warnings about acid rain, while people reported symptoms including aching throats and burning eyes.
The black rain likely resulted from precipitation passing through the smoke-laden air, washing down soot and other particles from the burning oil facilities. Anna Hansell, an expert at the University of Leicester in the UK, noted that the smoke's chemical makeup remains unclear but could include a mix of partially burnt carbon, polyaromatic hydrocarbons, and oxides of sulphur and nitrogen that form acids in the atmosphere. "It’s going to be quite a nasty toxic moisture," Hansell said.
The combustion of thicker, less refined oil produced incomplete burning, potentially releasing a variety of harmful particles, including fragments from concrete, glass, and plastics damaged in the strikes. Hansell added uncertainty about whether the dark color stems solely from greasy smoke or includes small oil droplets.
Health risks from the black rain include gastrointestinal issues if ingested, such as stomachaches or diarrhoea, and irritation to eyes and throats from acid components—symptoms already noted by locals. However, Hansell emphasized that the pervasive smoke poses a greater danger, as fine particles can penetrate deep into the lungs and enter the bloodstream, raising risks of cardiovascular disease, lung cancer, chronic lung conditions, and diabetes.
Environmental contamination could lead to toxins building up in water, fish, farm animals, and crops, affecting long-term health. While larger particles settle quickly, smaller ones may travel hundreds or thousands of kilometres on winds, potentially impacting other Middle Eastern countries, though concentrations would dilute farther afield.
Hansell recommended that people in Iran stay indoors, use face masks and goggles outdoors, and switch to bottled water if tap supplies show odd tastes or particles. She highlighted that such environmental damage transcends borders, affecting air and water systems regionally.
