We know all about Iran’s enriched uranium. But what about its nerve agents? And biological weapons?
US President Donald Trump assures us Tehran’s nuclear weapons program was “completely and totally obliterated” by joint Israeli-US air strikes in June last year – though its facilities have been repeatedly targeted again since the Iran war began.
But stealth fighters and bombers, cruise missiles and drones have been pounding thousands of other targets of opportunity, be they government, military, industrial or academic.
Any one of these could house another devastating threat. One Prime Ministers and Presidents have not been talking about.
“The deliberate use of biological weapons by Iran remains unlikely, but the risk has escalated significantly since US and Israeli strikes commenced,” warns biosecurity analyst Dr Cassidy Nelson.
If Iran doesn’t release them, US and Israeli bombs may.
“An accidental release from any one of these facilities – whether due to damage to infrastructure, a breakdown in protocols or simple abandonment – is a realistic possibility in the coming weeks and months,” Dr Nelson explains.
They could still be deliberately deployed. Even if the (surviving) Tehran leadership team doesn’t want them to be.
“When command structures fracture, when facilities are struck and personnel scatter, the custody of dangerous materials unravels,” argues biological threat analyst Dr Ashish Jha.
Anything can happen.
And likely will.
The Trump administration reportedly did not expect Iran to follow through with its threat to attack shipping in the Strait of Hormuz. We don’t know what Washington thinks of Iran’s biological warfare threat.
“The consequences of a release — deliberate or accidental — would be unlike anything disrupted oil markets can produce,” Dr Jha states.
“Covid-19 — which was not a weaponised pathogen and not optimised for lethality — erased tens of trillions of dollars from the global economy and reshaped daily life for years.”
The only certainty of war is uncertainty
Iran’s response to the US-Israeli bombing campaign has been full of surprises.
It has unexpectedly hit several vital radar installations.
A handful of its missiles have slipped past the best defences.
Its drones have damaged AI data centres, oil facilities and at least 11 US military installations. Its decapitated religious regime appears as strong as ever.
And it closed the Strait of Hormuz.
Then, last week, two long-range missiles streaked over the Indian Ocean towards the US-operated base on the British islands of Diego Garcia.
One failed in flight. The other was shot down.
But it demonstrated a military capability Washington DC did not believe Tehran had.
“The real surprise is that some senior leaders, both in the White House and on Capitol Hill, are acting surprised by Iran’s defiance and resilience,” argues retired US Lieutenant Colonel Jahara Matisek.
The US Naval War College analyst says Iran has been watching Israeli and US military operations for decades. Washington’s well-worn ‘shock and awe’ tactics were easy to anticipate.
“So, Tehran invested in decentralisation, dispersal, and redundancy,” Matisek argues.
“The point was not to stop the first punch, but to remain standing.”
And that means it can still fight back – in unexpected ways.
One option is to release chemicals that attack the nervous system. Or viruses tailored for maximum physical impact.
Iran itself suffered Iraqi biological weapon attacks in the late 1980s.
“The lesson Iranian leadership drew then was clear: never again would the country accept an asymmetry in unconventional capabilities,” Dr Nelson states.
“What followed, according to successive public intelligence assessments going back decades, was a sustained effort to develop biological agents under the cover of legitimate civilian research.”
Epic fury
“Iran may not be thriving, but it is surviving,” assesses Lieutenant Colonel Matisek.
“That distinction matters, because too much American strategic thinking is entrapped by the seductive belief that if the opening barrage is violent enough, the enemy’s coherence will unravel on schedule.
“Iran has spent decades developing the ability to deny that outcome.”
The fear is it may yet have a few tricks up its sleeve.
Writing for the Royal United Services Institution (RUSI), Dr Nelson says Iran’s deliberate tactic of hiding and dispersing its secret warfare capabilities has heightened that risk.
Especially for biological warfare.
“In December 2025, reports emerged that the Islamic Revolutionary Guard Corps (IRGC) was working to integrate biological and chemical payloads into long-range ballistic missiles as a ‘complementary deterrent’ to its conventional missile program,” she notes.
We now know Iranian missiles can reach half a world away.
And Israel has experienced the impact of another update – missiles carrying multiple warheads.
“Evidence of a warhead with a biological payload launched at foreign targets would invite catastrophic retaliation,” warns Dr Nelson.
“Domestic deployment to suppress an uprising or stage a false flag cannot be ruled out when decision-making shifts from strategic calculation to desperation.’
Then there’s the risk of accidental release.
“In plain English: The US may not know what it’s hit, what is now unguarded, or where it might go,” Dr Jha writes for the medical journal Stat.
“Unlike nuclear material, they don’t trigger radiation detectors at border crossings. Unlike chemical stockpiles, they can be small, portable, and capable of spreading on their own once released.
“A vial doesn’t need a missile to become a weapon.”
Risk mitigation
Threat-analysis think-tank the Stimson Centre warns that thorough plans to safeguard, intercept and seize nerve and biological agents need to be in place already.
“When the Soviet Union ended, a forward-looking group of US lawmakers and statesmen had been planning for months how to ensure that Soviet nuclear weapons were safe and secure amid any ensuing political turmoil,” it highlights in an assessment.
“It is less clear, however, that there has been any associated forethought given to securing the stockpiles not only of highly enriched uranium (HEU) and nuclear centrifuges, but of other dangerous nuclear, chemical, and biological materials and expertise …”
Iran is known to have at least 400kg of uranium enriched to a level of 60 per cent. At that state, only a few more hours in a centrifuge are needed to make it fully weapons-grade.
Nobody knows how much nerve or biological agent it has produced.
Only that it has.
Iran recruited the necessary scientists after the collapse of the Soviet Union in the 1990s. But these were dispersed among civilian medical and research institutions to continue their work.
Iran “maintains flexibility to use, upon leadership demand, legitimate research underway … to produce lethal biological weapons agents”, the US Office of the Director of National Intelligence assessed last year.
We don’t know what it is. We don’t know where it is. Or what condition it is in.
“Biological agents require safeguarding and careful maintenance. Without both, containment can fail,” warns Dr Nelson.
They can escape into the population. Or the wrong hands.
Once out, they’re almost impossible to track.
Which is why the risk of a nasty surprise – whether intentional or accidental – is disturbingly high.
“The most urgent question raised by this conflict is less about Iran than it is about us,” concludes Dr Jha.
“The war in Iran has exposed a gap in American preparedness that predates this conflict — and will outlast it.”
