The US and Israel mounted an attack on Iran’s Natanz uranium enrichment facility on Saturday, long regarded as Iran’s main enrichment site.“Following the criminal attacks by the United States and the usurping Zionist regime against our country, the … Natanz enrichment complex was targeted this morning,” the Tasnim news agency said, citing the Atomic Energy Organization of Iran, on Saturday.However, there was “no leakage of radioactive materials reported” at the Shahid Ahmadi Roshan enrichment facility in Natanz, about 220 km southeast of Tehran.The Times of Israel reported that Saturday’s attack on Natanz was carried out by the US using bunker buster bombs, citing the Kan public broadcaster.The International Atomic Energy Agency (IAEA) confirmed damage to the site, specifically to its entrance buildings and potential localised contamination. However, the agency reported no immediate increase in off-site radiation and called for restraint to avoid nuclear safety risks.The attack on Saturday marks the second attack by the US and Israel on the site since commencing its war against Tehran in February, and its third overall — Natanz was one of the three sites targeted by the US last June during the 12 Day War, alongside Fordow and Isfahan. The extent of damage from the latest attack is currently unknown.The Natanz Enrichment ComplexThe complex is home to two enrichment plants that were operational at the start of Israeli attacks in June 2025.Story continues below this adAlso in Explained | Desperate measures: Why Trump suspended sanctions on Iranian oil at seaOf these, the Fuel Enrichment Plant (FEP) was a vast underground facility designed to house 50,000 centrifuges, the uranium-enriching machines. It had 17,000 installed centrifuges, of which 13,500 were operational and enriching uranium up to 5% in June. However, the plant’s electricity infrastructure was destroyed in Israeli airstrikes, with the IAEA telling the BBC last June that all operational centrifuges were likely “severely damaged if not destroyed altogether”. A report by the Institute for Science and International Security (ISIS) in November 2025 confirmed that the site remained destroyed with no repairs or reconstruction for the damage from the bunker-busting GBU-57 bomb.The Pilot Fuel Enrichment Plant (PFEP) in Natanz is the smallest Iranian enrichment facility, and is located above ground. It was primarily a research and development (R&D) centre, with much of the R&D work since moved underground to the FEP. The PFEP had two interconnected full-size cascades (interconnected clusters of centrifuges) of up to 164 advanced centrifuges each, and enriched uranium to up to 60%. It also had up to 201 centrifuges enriching up to 2%. The PFEP was destroyed in the Israeli attack on June 13, and no reconstruction activity was noted in the ISIS report. The IAEA confirmed on March 3, 2026, that the facility had suffered significant damage in fresh bombings, with the facility’s entrances sustaining the most significant damage. High resolution imagery taken on March 2 shows the damaged personnel and vehicle entrancebuildings and ground photos of what they looked like before the attack. (Vantor via ISIS)Natanz was the first nuclear site to be targeted in the ongoing war by the US and Israel, with Iran claiming that the site had been struck twice that day.According to high-resolution satellite imagery analysed by ISIS, the strikes targeted the personnel entrances and the sole vehicle entrance to the underground enrichment plant. The two three-storey personnel entrance buildings sustained severe damage, as did the building covering the vehicle entrance ramp. The IAEA confirmed the damage on March 3.Story continues below this adIn a report dated March 3, the institute noted that the targeting of the entrances was likely motivated by Iranian activity detected in the days before the strike. Satellite imagery from February 28 showed that roadblocks previously placed in front of the vehicle entrance had been moved out of the way, and a vehicle was seen outside the tunnel entrance — indicating Iran may have been accessing the underground site. This, the ISIS believed, could have allowed Iran to recover centrifuge components and possibly enriched uranium cylinders from inside the facility.The Pickaxe Mountain, known locally as the Kūh-e Kolang Gaz Lā, located south of Natanz, was identified by Tehran as a site for a nuclear facility deep within the mountains. Iran’s stated goal was to fortify its nuclear facility against a possible last-ditch US weapon designed to destroy such sites. This site had not been targeted in June’s airstrikes.Expert Explains Iran War | Why the energy crisis calls for an early ceasefireAs of February, construction on the facility was nearing completion, with its security perimeter wall finished and tunnel entrances being hardened. It is claimed that the facility is being dug at an estimated depth of about 80 to 100 metres under hard granite rock in a bid to secure immunity against the American bunker-busting bomb.In November 2025, Iranian Foreign Minister Abbas Araghchi said that Iran had ceased all “undeclared nuclear enrichment” in the country, ever since the country’s nuclear facilities — and military facilities — were targeted in the 12-day military operation in June. “All of our facilities are under the safeguards and monitoring” of the International Atomic Energy Agency (IAEA), Araghchi then said. “There is no enrichment right now because our facilities, our enrichment facilities, have been attacked.”Story continues below this adHowever, the situation has since deteriorated significantly. The IAEA has been unable to access Iran’s nuclear facilities for more than eight months, and has stated it “cannot provide any information on the current size, composition or whereabouts of the stockpile of enriched uranium in Iran.” The whereabouts of Iran’s stockpile of uranium enriched to 60% — last confirmed by the IAEA as stored across Fordow, Natanz and Esfahan before the June 2025 strikes — remain unverified, with the IAEA having had no access to Iran’s nuclear facilities since June 13, 2025.Enrichment is the process by which the concentration of Uranium-235 (U235) is increased in a sample of natural uranium, which is primarily more than 99 per cent Uranium-238 (U238). U-235 has industrial applicability due to its fissile nature, meaning its nucleus can be broken down (or is fissionable) through a process that produces energy, and is capable of sustaining a chain reaction. A 3-5% enrichment level provides for electricity generation in nuclear power stations. However, highly-enriched uranium (HEU), with concentrations of 90% or more of U235, is required to generate nuclear weapons.Threat of a radiation leakAn attack on enrichment sites raises the risks of both chemical and radiological leaks. Nuclear facilities, by their very nature, store a lot of radioactive substances, particularly uranium in different forms, including in a gaseous state like uranium hexafluoride (UF6), and dust. Radioactive substances are unstable and release radiation over time. Some of these radiations, like gamma rays, are extremely harmful. They can penetrate the skin, damage cells and DNA, and cause cancer.These radioactive substances are stored and handled in carefully designed containers in any nuclear facility. These facilities are constructed to minimise the risk of a leak of radioactive substances in outer environment or sources of water or food.Story continues below this adAn attack on these facilities, like the one carried out by Israel or the US, can damage or disrupt the mechanisms that ensure safe storage and handling of these substances. Two of the biggest instances of radiological leaks are the accidents that happened in Chernobyl in 1986 and Fukushima in 2011. In both cases, large-scale radioactive substances escaped into the atmosphere as a result of accidents, posing a major threat to humans and others.Another recent threat was seen at the Zaporizhzhia nuclear power plant in Ukraine, which has been caught in the fight between Russian and Ukrainian forces. The Zaporizhzhia plant is the largest in Europe and has come under direct attack several times during the conflict. Thankfully, it continues to operate safely.