The world could be on the brink of a nuclear catastrophe as the United Nations has begun planning for radiation leaks triggered by the conflict in the Middle East between Israel, the United States and Iran. It’s reported the World Health Organisation (WHO) is already monitoring potential fallout from US-Israeli airstrikes on Iranian atomic sites.

Iran and Russia both allege that a projectile struck the grounds of the Bushehr nuclear power plant in the Islamic Republic, raising the specter of a radiological incident as Tehran’s war with Israel and the United States rages. And though no release of nuclear material was reported following the incident on Tuesday evening, it again underlines a longtime worry of Iran’s neighbours — that the power plant on the shores of the Persian Gulf could be hit by either an attack or a natural disaster such as an earthquake.

WHO director Hanan Balkhy told POLITICO: “The worst-case scenario is a nuclear incident, and that’s something that worries us the most.”

She added: “As much as we prepare, there’s nothing that can prevent the harm that will come … the region’s way – and globally if this eventually happens – and the consequences are going to last for decades.”

The Atomic Energy Organization of Iran later issued a statement saying “no financial, technical, or human damage occurred and no part of the plant was harmed.” Iran blamed the incident on the US and Israel, Tass later reported.

But Rafael Mariano Grossi, head of the UN’s International Atomic Energy Agency (IAEA), told journalists in Washington “any attack on any nuclear facility should always be avoided”.

The IAEA has had its inspections of Iran restricted over years of tensions over Tehran’s program after Trump unilaterally withdrew America from the 2015 nuclear deal with world powers.

Bushehr, as a running, civilian nuclear power plant, was left untouched during the 12-day war between Israel and Iran in June last year.

During that war, the US bombed three Iranian nuclear enrichment sites, destroying centrifuges and likely trapping Tehran’s stockpile of highly enriched, 60% uranium underground. In the time since, Iran has blocked IAEA inspectors from visit those sites.

A possible strike on a nuclear power plant could see a leak of radiation into the environment. That’s been a major concern in the years after Russia launched its full-scale invasion of Ukraine in 2022. Nuclear plants in Ukraine, built when the country was part of the Soviet Union, have come under attack and found themselves on the front lines of that war.

A radiation leak into the Persian Gulf would be an existential crisis for the Gulf Arab states, which rely on desalination plants on the gulf for their water supplies.