The head of the United Nations nuclear watchdog said Monday that Israel’s airstrikes on Iran’s Natanz uranium enrichment site may have caused contamination inside the facility.

IAEA Director General Rafael Mariano Grossi stated that radiation poses a serious risk if uranium is inhaled or ingested. However, he emphasized that the danger can be effectively controlled with proper safety measures, including the use of respiratory protection inside the facilities.

Grossi said radiation levels outside the Natanz facility remain within normal limits.

“The level of radioactivity outside the Natanz site has remained unchanged and at normal levels, indicating no external radiological impact to the population or the environment from this event,” Grossi said.

Grossi warned that military action near nuclear sites increases the chance of a radiation accident and hurts efforts to reach a diplomatic solution. “The danger is real if this continues,” he said.

Israel bombed the Natanz nuclear facility early Friday, launching the first wave of a major strike campaign targeting Iranian military and nuclear sites. Israeli officials described the operation as a necessary response to an imminent existential nuclear threat.

Grossi told BBC that it is very likely nearly all of the approximately 15,000 centrifuges at Iran’s largest uranium enrichment facility in Natanz were severely damaged or destroyed due to a power outage caused by the Israeli strike. 

He explained that these centrifuges rely on a stable and uninterrupted power supply to function safely, and a sudden loss of electricity can lead to malfunctions and mechanical failures.

At the Isfahan nuclear site, Grossi said four buildings were hit, including one used for converting uranium. There was no increase in radiation levels there either, according to Grossi.

Fordo, Iran’s third enrichment site, was not affected. The Bushehr nuclear power plant and the Tehran Research Reactor were also unharmed, according to Grossi. 

Grossi said the IAEA needs more data from Iran to understand the full impact. “Without access and information, we cannot assess the risks or provide help,” he said.