‘Black rain’ in Iran. What causes it and why it’s a concern

The sun over Tehran was blocked out this week as thick smoke billowed from oil depots bombed by US Israeli jets. Residents of the city reported “black rain”, which is rain with high levels of atmospheric pollutants in it, likely from the burning of heavy fuel, a low-quality byproduct of oil refining. This means this dark rain over Tehran likely contains hazardous cancercausing benzene, acetone and methylene chloride.

People are already feeling the effects. “The skin on my face is sore and raw. It burns,” Time magazine quoted a resident of Tehran as saying.

Unlike combustion inside car engines, which is total, the burning in the oil depots would’ve been less complete, releasing unburnt particles into the air. These particles can trigger a range of health conditions in people, including cardiovascular disease, lung cancer and even diabetes.

Then there’s acid rain. The oil in the depots also contains sulphur and nitrogen, which when burnt, form oxides that can react with moisture to trigger acidic precipitation. This rain can irritate the eyes and throat. And if it seeps into waterways, it can alter chemistry and harm aquatic life.

These hazards are a worricould stop the monsoon; in Bahrain, temperature dropped 10°C; Soviet devices began to detect soot in the air; and Turkey, Bulgaria, Pakistan all saw ‘black rain’.

Hardest hit was of course Kuwait where experts said environmental recovery would take at least 100 years. Nearly 90% of the soil that was contaminated by oozing oil is still exposed to the environment.

Firefighters sent to douse the wells suffered health issues. “The doctor said it was as if I was smoking three packs of cigarettes every day for three years,” a woman firefighter told The Guardian in 2021, 30 years after event.
Experts have warned the fresh outbreak of war risks a repeat of the disaster. For now, Iranians in the affected zones have been told to stay indoors. some repeat of what Iranians and millions more in nearby countries experienced in the early ’90s, when Saddam Hussein’s forces set off the “worst environmental disaster after Chernobyl and Bhopal”, as they blew up 700 Kuwaiti oil wells during the first Gulf war.

The fires burned for 10 months before they were extinguished; 90% of them with just seawater. But those infernos caused a catastrophe, effects of which were felt as far as the Himalayas where two inches of ‘black snow’ fell. In India, there was concern the smoke