WHO Issues Health Alert After Oil-Contaminated Black Rain Reported Across Iran

A rare environmental phenomenon known as “black rain” has been reported in parts of Iran, prompting a warning from the World Health Organization about potential health risks linked to polluted rainfall. The unusual precipitation, reportedly darkened by soot, oil residues, and toxic particles, emerged after fires and explosions at oil facilities released large amounts of pollutants into the atmosphere. As these contaminants mixed with moisture in the air, they were carried down to the ground through rainfall, creating the dark, oily rain observed in affected areas.

Health officials say the phenomenon could pose immediate and long-term risks to public health, particularly for people exposed to polluted air or contaminated rainwater. A spokesperson for the World Health Organization confirmed that the agency had received reports of oil-laden rainfall and warned that the conditions could worsen respiratory problems. Authorities in affected regions have advised residents to stay indoors and limit exposure to polluted air until conditions improve.

Scientists explain that black rain occurs when raindrops fall through air heavily polluted with soot, ash, or industrial chemicals. During this process—often referred to as “atmospheric scavenging”—raindrops absorb airborne particles and carry them to the ground. The phenomenon can occur during major environmental disasters such as large oil fires, industrial pollution incidents, volcanic eruptions, or widespread wildfires, all of which release heavy smoke and chemicals into the atmosphere.

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In the current situation, environmental experts believe that burning oil infrastructure released hydrocarbons, sulphur compounds, and other pollutants into the air. These particles, including black carbon and fine soot, can penetrate deep into the lungs when inhaled. Toxic substances such as polycyclic aromatic hydrocarbons and trace metals may also be present, potentially triggering respiratory issues, inflammation, or irritation of the skin and eyes.

Health specialists warn that prolonged exposure to these pollutants may carry serious long-term risks. In addition to respiratory illnesses such as asthma and bronchitis, contaminated rainfall may also affect soil quality, crops, and water sources. Some pollutants linked to black rain have been associated with increased risks of chronic diseases, including cancer, particularly when exposure occurs over extended periods.

Although rare, black rain has been documented during several major historical events. One of the most well-known examples occurred after the Atomic Bombing of Hiroshima, when ash, debris, and radioactive particles fell as dark rain across large areas. Similar conditions were reported during the Gulf War Oil Fires, when hundreds of burning oil wells filled the atmosphere with smoke and pollution, highlighting the severe environmental and health consequences that can follow large-scale industrial or wartime fires.

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