Iran accumulated roughly 11 tons of enriched uranium over the past eight years since President Donald Trump withdrew the United States from the 2015 nuclear deal, but much of it is now unaccounted for after recent military strikes.

A New York Times investigation released on Friday uses quarterly reports from the International Atomic Energy Agency (IAEA) to track the scale of the stockpile, finding Tehran steadily expanded its nuclear capacity after Trump exited the landmark accord in 2018 and reimposed sanctions.

At that time, Iran had far less than a single bomb’s worth of enriched uranium under strict limits imposed by the deal.

The investigation found this changed rapidly and Tehran first breached caps on low-level enrichment, then escalated to 20% purity in 2021, a threshold widely seen as a critical step toward weapons-grade material. Enrichment climbed further to 60% in the following years, bringing Iran within reach of the 90% level typically required for nuclear arms.

Efforts by former President Joe Biden’s administration to revive the deal failed as Iran continued to expand both the size and purity of its stockpile. By 2025, according to the findings, growth had accelerated to its fastest pace since international monitoring began.

This changed again in June 2025, when Trump, by then re-elected, launched Operation Midnight Hammer, strikes on key nuclear facilities, including Natanz, Fordow and storage tunnels near Isfahant. Weeks later, Iran halted cooperation with the IAEA, cutting off on-the-ground inspections and leaving much of the stockpile’s status unverified.

Some material is believed to be buried under debris from the bombed facilities or stored in hardened underground sites, though this cannot be independently confirmed. While satellite surveillance continues, experts say it is difficult to determine the precise condition or accessibility of the uranium.

Officials in the Trump administration have argued that the remaining stockpile is of limited immediate use due to damage inflicted on Iran’s nuclear infrastructure.

However, according to the report, analysts warn that the possibility of undisclosed enrichment sites cannot be ruled out, particularly near Isfahan, where large portions of the uranium are thought to have been stored.

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