Common Questions

Was Fordow destroyed in the 2026 Iran strikes?: 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
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

Background

Fordow is Iran's most hardened nuclear facility and the one site US-Israeli strikes could not credibly destroy without the GBU-57 Massive Ordnance Penetrator. Built 100 metres inside a mountain near Qom, the facility was designed to survive conventional bunker-busters. Defence analysts confirmed that only GBU-31 2,000-lb munitions were used in the opening weeks of the 2026 campaign, weapons that penetrate just 1-2 metres of reinforced concrete, far short of Fordow's depth . CENTCOM later confirmed the GBU-72 Advanced 5K Penetrator was used against nuclear sites including Fordow .

Fordow houses around 2,700 centrifuges and was Iran's primary site for enrichment to 60% U-235 before inspectors were expelled. The IAEA has been denied access for over eight months. Iran holds 440.9 kg of 60%-enriched uranium across its facilities; if further enriched to weapons-grade 90%, that stockpile is sufficient for approximately seven nuclear devices. IAEA Director General Grossi assessed that military action cannot eliminate Iran's nuclear programme .

The IAEA disclosed in early March 2026 that Iran has a fourth enrichment site at Isfahan, whose operational status inspectors cannot determine . Fordow's survival matters beyond the physical: it is Iran's insurance against surface-level destruction elsewhere and the centrepiece of its deterrent posture.

How the World Sees Them

IAEA

Inspectors have had no access to Fordow for over eight months. The agency cannot verify stockpile movements or whether centrifuges remain operational.

Iran

Fordow is the proof that enrichment survives air power. Built specifically to resist attack, it anchors Tehran's claim that the nuclear programme is indestructible.

United States

CENTCOM used GBU-72 deep-penetration munitions against Fordow. Whether the underground enrichment halls were destroyed has not been independently verified.