Unexploded U.S. GBU-57 Bunker-Buster Bombs Inside Iran’s Nuclear Facilities Expose Dangerous Legacy of the 12-Day War
Abbas Araghchi’s disclosure that unexploded U.S. GBU-57 bunker-busting bombs may remain inside Iranian nuclear facilities highlights unresolved safety risks, inspection deadlock, and long-term military-technical consequences of the 12-day war
(DEFENCE SECURITY ASIA) — Iran’s Foreign Minister Abbas Araghchi delivered one of the most consequential post-conflict disclosures to date when he confirmed that unexploded U.S. munitions—believed to potentially include GBU-57 Massive Ordnance Penetrator bunker-busting bombs—remain embedded within multiple Iranian nuclear facilities targeted during the conflict.
“There are unexploded bombs in some Iranian facilities that were subjected to bombing during the 12-day war,” Araghchi stated, a remark that immediately reframed the episode from a concluded kinetic exchange into an ongoing latent security crisis involving buried penetrators, radiological exposure risks, and unresolved international oversight challenges.
Araghchi further warned that “we are now facing security threats and safety concerns, including possible radiation exposure and unexploded ordnance,” a statement that directly explains Iran’s refusal to allow International Atomic Energy Agency (IAEA) inspections under pre-war protocols and signals a recalibration of post-strike nuclear governance frameworks.
The disclosure injects a new dimension into global military-technical discourse, as unexploded U.S. bunker-busting systems—potentially GBU-57s designed for deep, hardened targets—alongside cruise missile components could offer Iran unprecedented access to advanced American weapons engineering with long-term implications for missile development, counter-penetration doctrine, and asymmetric deterrence.
From a strategic perspective, the presence of unexploded deep-penetration ordnance inside sensitive nuclear infrastructure represents a dual-use liability, simultaneously constraining inspection access while creating an intelligence windfall that could reshape Iran’s indigenous weapons trajectory.
Araghchi’s remarks should therefore be understood not merely as post-war commentary, but as a strategic signal to Washington, Tel Aviv, and international regulators that the consequences of Operation Midnight Hammer remain active, unresolved, and potentially counterproductive.
The situation also underscores how modern deep-strike campaigns against hardened nuclear targets carry long-tail escalation risks, where unexploded penetrators such as the GBU-57 can outlast political objectives and re-enter strategic competition through technological exploitation.
At its core, the disclosure reframes the 12-day war as an unfinished strategic contest, where buried ordnance, suspended inspections, and technology diffusion now define the post-conflict battlespace.
The confirmation that U.S. munitions—possibly including failed-to-detonate GBU-57 bunker busters—remain lodged within Iran’s most sensitive nuclear installations exposes a structural vulnerability in Western counter-proliferation doctrine, revealing how even precision-guided deep-strike campaigns can generate enduring strategic liabilities when destruction thresholds fall short of total neutralisation.
In practical military terms, such unexploded penetrators transform Iran’s damaged nuclear sites into contested technological spaces, where safety risks, intelligence exploitation, and political leverage intersect, complicating any future remediation, inspection, or de-escalation efforts under international supervision.
Strategically, this condition grants Tehran a rare form of post-conflict bargaining power, enabling it to frame inspection delays not as obstructionism but as unavoidable risk management, while simultaneously leveraging the situation to extract concessions in any renewed nuclear or sanctions-related negotiations.
Taken together, these dynamics demonstrate that the 12-day war did not merely pause Iran’s nuclear trajectory but reshaped it into a more opaque, technically resilient, and geopolitically entangled challenge, where the physical remnants of U.S. firepower—potentially including unexploded GBU-57s—now influence strategic calculations across the Middle East and beyond.
Last Year, The U.S. Urges Lebanon to Surrender Unexploded U.S-Made Precision Munition
The United States formally requested Lebanon in late 2024 to hand over an unexploded Israeli precision-guided munition following Israeli airstrikes against Hezbollah positions, after intelligence assessments determined that the weapon had failed to detonate and remained largely intact on Lebanese territory.
Washington’s request was driven by deep concern that sensitive U.S.-origin guidance and navigation technologies embedded within the munition could be recovered by Hezbollah and subsequently transferred to Iran for technical analysis and exploitation.
U.S. defence officials did not treat the incident as a routine battlefield malfunction but rather as a serious counter-intelligence risk, given Iran’s well-documented history of reverse-engineering unexploded Western weapons and incorporating their technologies into indigenous missile and unmanned aerial vehicle programmes.
The munition, believed to be a U.S.-supplied precision strike weapon integrated into Israel’s operational arsenal, reportedly contained advanced components including inertial navigation systems, satellite-aided guidance modules, and hardened electronics designed to withstand jamming and electronic spoofing.
From Washington’s strategic perspective, even partial access to such components could allow Iran to enhance its own precision-guided munitions, significantly improve the accuracy of Hezbollah’s rocket and missile arsenal, or develop more effective countermeasures against Israeli and U.S. air power.
This context helps explain why Abbas Araghchi’s later public statement regarding unexploded U.S. munitions inside Iranian nuclear facilities has reportedly generated unease in Israel, as it appears to confirm that Iran may already possess access to advanced Western strike technology.
Israeli defence planners fear that Araghchi’s disclosure signals not merely a post-war safety concern but a calculated strategic message indicating Iran’s ability to exploit unexploded precision weapons for intelligence gathering and long-term technological gain.
For Israel, the possibility that Iran could analyse bunker-busting bombs or precision-guided systems used by both the United States and Israel poses a direct challenge to long-standing qualitative military superiority, particularly in deep-strike operations against hardened and underground targets.
The Lebanese case illustrates how unexploded ordnance has evolved into a strategic liability in modern warfare, prompting urgent recovery efforts to prevent adversaries from transforming failed strikes into valuable technological windfalls.
Taken together, the U.S. request to Lebanon and Israel’s reaction to Araghchi’s remarks underscore a shared Western anxiety that contemporary precision warfare increasingly leaves behind exploitable remnants capable of reshaping future battlefields and shifting the balance of military power.
The 12-Day War and the Strategic Anatomy of Operation Midnight Hammer
The 12-day war that erupted on 13 June 2025 marked the most direct and technologically intensive confrontation between Iran, Israel, and the United States in modern Middle Eastern history, transforming decades of shadow warfare into an open, multi-domain kinetic exchange.
Israel’s initial pre-emptive strikes targeted Iranian military commanders, nuclear scientists, and enrichment infrastructure, triggering a rapid Iranian response involving ballistic missiles and long-range UAVs aimed at Israeli military, intelligence, and command facilities.
The United States entered the conflict on 22 June 2025, launching Operation Midnight Hammer, which Washington characterized as a “narrowly tailored” campaign designed to “destroy or severely degrade” Iran’s nuclear program and force Tehran back to negotiations.
More than 125 aircraft and 4,000 personnel were involved, with strike packages launched from U.S. strategic bases, including Whiteman Air Force Base, underscoring the scale of American power projection.
At the center of the operation was the employment of GBU-57A/B Massive Ordnance Penetrator (MOP) bunker-busting bombs and Tomahawk land-attack cruise missiles, selected specifically for their ability to neutralize deeply buried and hardened nuclear targets.
Fourteen GBU-57s, each weighing approximately 13,600 kg (30,000 lb), were reportedly dropped on Fordow and Natanz, while more than 30 Tomahawks struck surface and auxiliary infrastructure at Isfahan.
The conflict resulted in hundreds of casualties, including senior Iranian commanders and nuclear experts, while causing significant physical damage to nuclear facilities without conclusively eliminating Iran’s technological base.
This strategic ambiguity now defines the post-war environment, where destruction of infrastructure has not equated to eradication of capability.
Unexploded Ordnance and the Persistent Nuclear Safety Crisis
The presence of unexploded U.S. munitions inside Iranian nuclear facilities represents a persistent and compounding safety hazard, blending conventional explosive risk with potential radiological exposure in environments designed for sensitive nuclear processes.
As Araghchi warned, “Strikes on Iran’s nuclear facilities had created serious dangers, including possible radiation exposure,” a concern magnified by the fact that bunker-busting weapons are engineered to detonate deep underground, often adjacent to enrichment halls and reactor-related infrastructure.
Unexploded ordnance, particularly large-scale penetrators such as the GBU-57, can result from fuse malfunction, sub-optimal impact angle, or unexpected geological composition, leaving massive high-explosive devices buried beneath reinforced concrete and rock strata.
Such conditions render post-strike inspection, repair, and decontamination operations exceptionally dangerous, effectively denying access to both Iranian engineers and international inspectors.
Iran’s refusal to permit IAEA inspections without a revised framework must therefore be interpreted as a technical safety decision as much as a political stance, reflecting the real risks posed by unexploded penetrators in nuclear environments.
The situation also complicates emergency response planning, as detonation or degradation of buried explosives could release radioactive material, creating localized contamination zones with long-term environmental consequences.
This unresolved ordnance challenge underscores how kinetic counter-proliferation strikes can generate secondary nuclear risks, even when reactors are not directly targeted.
Reverse Engineering Risks and the Technological Irony of U.S. Strikes
Beyond safety concerns, unexploded U.S. munitions embedded within Iranian facilities present a strategic intelligence and technology-transfer risk that could reshape Iran’s military-industrial capabilities.
As Araghchi implied, “Unexploded munitions can be reverse engineered,” a statement that echoes longstanding defence-industry realities where captured or intact weapons systems provide invaluable insights into adversary technology.
The GBU-57’s hardened casing, delayed-fuse mechanisms, guidance architecture, and penetration physics represent some of the most advanced bunker-busting technologies ever deployed, making even partial recovery strategically significant.
Similarly, Tomahawk cruise missiles, with their terrain-following navigation, low-altitude penetration profiles, and mature guidance systems, could inform Iran’s indigenous cruise missile programs such as Soumar and Hoveyzeh.
Historically, reverse engineering has proven transformative, from the Soviet replication of the B-29 to Iran’s adaptation of captured RQ-170 Sentinel drone technologies.
In this context, unexploded U.S. weapons risk accelerating Iran’s deep-penetration warhead development, missile survivability, and counter-bunker doctrines, directly undermining the original strategic objectives of Operation Midnight Hammer.
The irony is stark: a campaign intended to suppress Iran’s technological trajectory may have inadvertently supplied the raw material for its advancement.
Nuclear Sovereignty, Enrichment Rights, and Diplomatic Deadlock
Araghchi has consistently framed Iran’s post-war posture as a defense of sovereign nuclear rights, stating unequivocally, “No one has the right to impose on us what we should do or own regarding the right to enrich uranium.”
He further emphasized that “uranium enrichment is essential for the country’s future needs in fuel, agriculture, and industry,” reinforcing Tehran’s long-standing position that its nuclear program remains peaceful despite international skepticism.
This stance comes amid the collapse of the JCPOA framework, following U.S. withdrawal in 2018 and Iran’s subsequent enrichment escalation to near-weapons-grade levels by 2025.
The IAEA’s declaration of Iranian non-compliance with NPT safeguards for the first time since 2005 provided the immediate pretext for Israel’s strikes and U.S. intervention.
Yet Araghchi has maintained that while “many of our equipment in these facilities have been destroyed, our technologies remain,” underscoring the resilience of Iran’s scientific base.
This technological persistence complicates diplomatic pathways, as physical damage has not translated into strategic capitulation.
Global and Asian Strategic Implications of the Unresolved Ordnance Crisis
The lingering presence of unexploded U.S. ordnance inside Iranian nuclear sites reverberates far beyond the Middle East, reshaping global non-proliferation norms and strategic calculations across Asia-Pacific defence communities.
China and Russia’s condemnation of the strikes and their joint declaration of the JCPOA’s effective termination highlight a fracturing international consensus on nuclear governance.
For Asia, the episode underscores how Middle Eastern conflicts can indirectly influence missile technology diffusion, asymmetric warfare doctrines, and regional deterrence balances, particularly in the Indo-Pacific.
The Strait of Hormuz, through which nearly 20 percent of global oil supply transits, remains vulnerable to escalation, with energy security implications for economies from Japan to Southeast Asia.
From a defence-industrial perspective, the potential reverse engineering of U.S. penetrator technology introduces new variables into global arms competition, affecting future bunker-hardening strategies worldwide.
Ultimately, the unexploded bombs beneath Iran’s nuclear facilities symbolize the unresolved nature of modern conflict, where weapons outlast wars and strategic consequences continue to unfold long after ceasefires are declared.
Abbas Araghchi’s disclosure that unexploded U.S. munitions remain inside Iranian nuclear facilities encapsulates the enduring strategic uncertainty of the 12-day war, revealing how kinetic intervention has produced latent risks, technological paradoxes, and diplomatic deadlock rather than definitive resolution.
“Our facilities have been damaged, seriously damaged, but our technologies are still there, and technology cannot be bombed,” Araghchi stated, a remark that may ultimately define the conflict’s legacy.
As negotiations in Muscat continue under a cloud of mistrust—“They tried everything and failed… We do not trust them”—the unexploded remnants of war remain buried beneath Iran’s nuclear heartland.
Whether these weapons become catalysts for renewed diplomacy or accelerants of future escalation will shape global security trajectories for years to come.
— DEFENCE SECURITY ASIA
