CENTCOM confirmed GBU-72 penetrators were used against Fordow. Whether the underground enrichment halls were destroyed has not been independently confirmed. The IAEA has no current inspector access.Source: CENTCOM

Can the GBU-57 destroy Fordow?

The GBU-57 Massive Ordnance Penetrator was the weapon designed to defeat Fordow. Defence analysts confirmed it was not used in the opening weeks of the 2026 campaign. The GBU-72 was confirmed used, but its effectiveness against Fordow's depth has not been independently verified.Source: The War Zone / Army Recognition

How deep underground is Fordow?

Fordow is built approximately 100 metres inside a mountain, making it resistant to conventional bunker-busting munitions. Only the GBU-57 Massive Ordnance Penetrator is considered capable of reaching its enrichment halls.Source: The War Zone / Army Recognition

Background

Fordow is Iran's most hardened nuclear facility, built 100 metres inside a mountain near Qom to survive conventional air strikes. Twelve GBU-57 Massive Ordnance Penetrators delivered by B-2 stealth bombers during Operation Midnight Hammer on 22 June 2025 sealed the facility's ventilation shafts. No enrichment activity has resumed; tunnel portals remain backfilled as of early 2026. Defence analysts confirmed in March 2026 that the GBU-31 2,000-lb munitions used in later strikes penetrate just 1-2 metres of reinforced concrete, FAR short of Fordow's depth, and a February 2026 operation (Roaring Lion / Epic Fury) did not retarget the site.

Fordow housed around 2,700 centrifuges and was Iran's primary site for enrichment to 60% U-235 before the June 2025 strikes. The IAEA has had no inspector access for over four months as of 23 June 2026, leaving the physical state of the centrifuge cascade halls unverifiable from the ground. Iran holds roughly 440.9 kg of 60%-enriched uranium across its facilities; the agency lost continuity of knowledge over that stockpile in February 2026 and cannot confirm where it is held. On 23 June, Trump claimed Iran had agreed to full IAEA inspections; Iran's foreign ministry denied any such arrangement within hours, and IAEA Director General Grossi said inspections would happen but named no date. Bombed sites including Fordow remain closed.

Fordow's survival matters beyond the physical. Iran's Foreign Minister Abbas Araghchi confirmed on 13 April 2026 that no Iranian facility can currently enrich uranium, making the nuclear programme's residual leverage rest entirely on the intact stockpile rather than production capacity. Fordow remains the centrepiece of Tehran's deterrent argument: that enrichment infrastructure buried this deep cannot be permanently destroyed by air power alone.

More questions

Is Fordow operational after the 2026 strikes?

Operational status is unknown. IAEA inspectors have no access. The IAEA Director General assessed that Iran's enrichment capacity and stockpile likely survive even if surface infrastructure was damaged.Source: IAEA

How does Fordow compare to Natanz?

Both are underground Iranian enrichment facilities. Fordow is built inside a mountain at 100m depth and is considerably harder to destroy than Natanz. Both were targeted in the 2026 campaign with deep-penetration munitions; Fordow requires heavier weapons to reach its enrichment halls.Source: Lowdown

Was Fordow actually destroyed in the 2026 strikes?

Fordow was sealed by twelve GBU-57 Massive Ordnance Penetrators during Operation Midnight Hammer in June 2025. Tunnel portals remain backfilled and no enrichment has resumed, but the IAEA cannot confirm the underground centrifuge halls were physically destroyed because inspectors have had no access since February 2026.Source: IAEA monitoring update via American Nuclear Society, April 2026

What is the Fordow nuclear facility and why is it so hard to bomb?

Fordow is an Iranian uranium enrichment plant built 100 metres inside a mountain near Qom. Its depth means standard bunker-buster munitions cannot reach the centrifuge halls; only the GBU-57 Massive Ordnance Penetrator, the largest bunker-buster in the US arsenal, was assessed as capable of penetrating it.Source: Defence analysis, The War Zone and Army Recognition, March 2026

Can the IAEA inspect Fordow after the ceasefire?

As of 23 June 2026, Fordow remains closed to IAEA inspectors. Trump claimed Iran had agreed to full nuclear inspections; Iran's foreign ministry denied any such deal existed. IAEA Director General Grossi said inspections would happen under the Islamabad MOU but named no date.Source: Lowdown reporting, 23 June 2026

How many nuclear weapons could Iran build with its enriched uranium?

Iran holds approximately 440.9 kg of 60%-enriched uranium. If further enriched to weapons-grade 90%, analysts estimate that is sufficient material for roughly seven nuclear devices. The IAEA lost continuity of knowledge over the stockpile in February 2026 and cannot verify its current location.Source: IAEA Board of Governors report, June 2026

When did the US strike Fordow?

The US struck Fordow on 22 June 2025 during Operation Midnight Hammer, using twelve GBU-57 Massive Ordnance Penetrators dropped by B-2 stealth bombers. A February 2026 campaign (Operation Roaring Lion / Epic Fury) did not retarget Fordow.Source: American Nuclear Society IAEA monitoring relay, April 2026

How the World Sees Them

IAEA

Inspectors have had no access to Fordow since February 2026. The agency cannot verify stockpile movements, whether centrifuges remain intact, or whether any reconstruction has begun.

Iran

Fordow is the proof that enrichment survives air power. Built specifically to resist attack, it anchors Tehran's claim that the nuclear programme cannot be permanently eliminated.

United States

Operation Midnight Hammer sealed Fordow's ventilation shafts in June 2025. Whether the underground centrifuge halls were physically destroyed remains unconfirmed, a gap that shapes every subsequent negotiation demand.