What is the 'acid rain' after US strikes in Iran?
Mar 17th 2026
Reports of black, acidic rain after strikes on oil depots in Iran reflect rainout of toxic smoke and combustion products, bringing acids, fine particles and carcinogens that pose immediate and long-term health and environmental risks.
- Black rain likely contains oil residues, ultrafine particles (PM2.5), polycyclic aromatic hydrocarbons, acids formed from sulfur and nitrogen oxides, and possible heavy metals.
- The label acid rain understates the danger because the rain also brings hydrocarbons and toxic particles that settle on surfaces and into water.
- Short-term health effects include headaches and breathing problems, with higher risk for children, the elderly, pregnant people, and those with lung disease.
- Long-term exposure can increase risks of cancer, cardiovascular disease, and neurological harm linked to inhaled PM2.5 and carcinogens.
- Immediate precautions are to stay indoors, wear masks if exposed, close windows, and clean indoor hard surfaces when it is safe to do so.
Articles
- Why is black rain falling on Iran and how dangerous is it? www.newscientist.com
- What is the ‘acid rain’ in the wake of U.S. bombings in Iran? www.scientificamerican.com
- ‘Black rain’ in Tehran — what are the health effects? www.nature.com