Iranian authorities are reporting no signs of off-site radiation or contamination in the wake of U.S. attacks on three of the country's nuclear sites.

That's according to a statement put out by the International Atomic Energy Agency on Sunday. Rafael Mariano Grossi, the agency's Director General, said that "as of this time, we don't expect that there will be any health consequences for people or the environment outside the targeted sites."

"We will continue to monitor and assess the situation in Iran and provide further updates as additional information becomes available," he added.

The three sites hit by U.S. bombs — Fordo, Isfahan, and Natanz — contained nuclear material in the form of uranium enriched to different levels, the agency said. At least, that's the most recent information it had verified "before the attacks on Iran began on 13 June."

The two major kinds of uranium isotopes found at this type of facility "are at the low end of hazard with regard to radioactive materials," says Edwin Lyman, director of nuclear power safety at the Union of Concerned Scientists in Washington, D.C.

"So there's not a significant, dire health threat if those materials got released to the environment," he told NPR before the U. S. strikes.

What's more, these facilities would have mostly been working with uranium in the form of a gas called uranium hexafluoride. The molecules of this gas are big and heavy. That means when a container that holds this gas gets ruptured, the gas doesn't travel far through the air, according to Emily Caffrey, a health physics expert at the University of Alabama at Birmingham.

Earlier this month, when an attack by Israel damaged the aboveground portion of the Natanz Fuel Enrichment Plant, the level of radioactivity outside the site "remained unchanged and at normal levels, indicating no external radiological impact to the population or the environment from this event," the IAEA reported.

Inside the site, however, there was "both radiological and chemical contamination."

In the past, the IAEA's Director General has voiced his opposition to military attacks on Iran's nuclear sites, saying that "though they have not so far led to a radiological release affecting the public, there is a danger this could occur."

Neighboring countries have been watching the situation closely, according to a statement put out by the government of Kuwait, which cited the Gulf Cooperation Council (GCC) as saying on Sunday that "no abnormal radiation levels have been detected in any of the member states."

"Monitoring of the situation and its developments will continue through established surveillance and early warning systems," the statement said, "and reports will be issued regularly."

Copyright 2025 NPR