HR 4281
Bunker Buster Act of 2025
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Bill overview
The Bunker Buster Act of 2025 authorizes the President to take actions to prepare Israel for potential contingencies if Iran develops a nuclear weapon. This includes providing infrastructure for specialized ordnance, storing or transferring the Massive Ordnance Penetrator (MOP) weapon, training Israeli personnel, and conducting joint research and development with Israel. The bill reflects growing concerns about Iran’s nuclear program and its potential impact on regional stability, particularly considering recent IAEA reports and military actions.
Key provisions
- Authorizes the President to provide infrastructure in Israel for destroying underground nuclear facilities.
- Permits the storage of the Massive Ordnance Penetrator (MOP) in Israel.
- Allows for the transfer of the MOP to Israeli custody under specific conditions.
- Provides for training of Israeli personnel on the use of specialized ordnance.
- Facilitates joint research and development with Israel to enhance ordnance capabilities.
- Defines the NPT Safeguards Agreement for reference.
- Requires a dual key control system for deployment of the MOP.
- Sets conditions for exercising the President’s authority, including a determination of vital national security interests.
Who is affected
- United States
- Israel
- Iran
- International Atomic Energy Agency (IAEA)
- Palestinian Territories (through UNRWA)
Notable changes
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119th CONGRESS — 1st Session
H. R. 4281
IN THE HOUSE OF REPRESENTATIVES
A BILL
To authorize the President to take actions to ensure Israel is prepared for all contingencies if Iran seeks to develop a nuclear weapon, and for other purposes.
This Act may be cited as the Bunker Buster Act of 2025
.
Congress finds the following:
The United States Nuclear Regulatory Commission defines high-enriched uranium
as uranium enriched to at least 20 percent uranium-235.
Under the 2015 Joint Comprehensive Plan of Action, Iran agreed to refrain from producing enriched uranium containing more than 3.67 percent uranium-235 for 15 years.
On January 13, 2019, the head of the Atomic Energy Organization of Iran, Dr. Ali Akbar Salehi, told the Fars News Agency, If we want to come out of the nuclear deal and produce, within four days we could start our 20 percent.
.
On April 16, 2021, Dr. Salehi told the state television that Iran had begun enriching uranium to 60 percent.
On July 14, 2021, the former President of Iran, President Hassan Rouhani, said during a press conference that Iran has the knowledge and ability to enrich weapons-grade uranium at 90 percent.
According to an International Atomic Energy Agency (IAEA) report, as of May 11, 2024, Iran has 142.1 kilograms (313.2 pounds) of uranium enriched up to 60 percent, an increase of 20.6 kilograms (45.4 pounds) since the last report by the United Nations watchdog in February. Uranium enriched at 60 percent purity is just a short, technical step away from weapons-grade levels of 90 percent. Iran’s overall stockpile of enriched uranium stands at 6,201.3 kilograms (1,3671.5 pounds), which represents an increase of 675.8 kilograms (1,489.8 pounds) since the IAEA’s previous report.
The current stockpile is enough to make several nuclear bombs according to the criteria the IAEA uses to make such determinations.
Reports indicate the Iran may be constructing new facilities to help expand its nuclear program.
In June 2024, the IAEA elected to censure Iran for its violation of international responsibilities under its nuclear agreement and demanded its cooperation, including the readmittance of inspectors and the restoration of camera surveillance at nuclear sites.
In June the IAEA announced Iran is installing 1,400 new advanced centrifuges at its Fordow facility.
Since October 7, 2023, Israel has been at war with Hamas in the Gaza strip, which has used Iranian funding and direction to target the Jewish state.
Hamas continues to hide within civilian infrastructure, fire rockets at humanitarian crossings, and steal international aid and resources that are only further hurting the Palestinian civilians. Hamas has built tunnels under United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) buildings, including a large data center under UNRWA’s Gaza base, and stores weapons in UNRWA schools.
As of June 2024, Ansarullah, or otherwise known as the Houthis, have launched at least 60 attacks at ships. They have seized 1 vessel, killed 4 sailors, and sunk 2 ships since November 2023. The Houthis have also launched drones, missiles, and mortars toward Israel and at United States and its allies. The Houthis operate with Iranian funds.
Since October 7, 2023, Hezbollah has launched over 5,000 rockets, missiles, and drones at Israel. Iran has, provided Hezbollah with more than 100,000 missiles and rockets.
Iran is expanding its missile capacity and weaponization program to further assist their proxies across the region.
On June 12, 2025, 60 days had lapsed without an agreement in diplomatic negotiations to prevent Iran from attaining a nuclear weapon.
On June 12, 2025, IAEA board declared Iran in violation of its non-proliferation obligations.
On June 13, 2025, Israel launched a coordinated series of strikes against Iranian military and government targets in efforts to disrupt Iran’s development of a nuclear weapon based on Israeli intelligence assessment that Iran had taken steps putting them closer to achieving nuclear latency.
It is the sense of Congress that the United States should—
seek to extend the limitations on Iran’s enriched uranium, including through engagement in multilateral diplomatic initiatives;
ensure that Israel and other allies are prepared for all contingencies if Iran pursues development of a nuclear weapon;
send a clear signal to Iran that development of a nuclear weapon will never be tolerated; and
reaffirm the United States commitment to deter Iranian nuclear development with a credible military threat.
Subject to the preliminary conditions described in subsection (b), the President is authorized to take the actions described in subsection (c), upon the request of the Government of Israel, to ensure Israel is prepared for all contingencies if Iran seeks to develop a nuclear weapon.
The actions described in this subsection are the following:
To provide for the construction of infrastructure in Israel to accommodate large ordnance systems that are designed to destroy underground nuclear infrastructure, including—
construction of extended runways for aircraft that carry the Massive Ordnance Penetrator (MOP);
basing options for such aircraft; and
munition storage facilities.
To store in the territory of Israel the MOP or related munitions described in paragraph (1), to be used by the United States except as provided in subparagraph (B).
To transfer the MOP or related munitions described in paragraph (1) to Israeli custody if the President determines and certifies to Congress that—
Iran—
is in noncompliance with the NPT Safeguards Agreement;
has modified its implementation of the NPT Safeguards Agreement (including modified Code 3.1); or
as determined by the President, has reduced access of inspectors of the IAEA in such a manner so as to be prejudicial to the IAEA’s ability to provide confidence as to the non-diversion of declared nuclear material and absence of undeclared nuclear activities;
it is vital to the national security of the United States to do so;
Israel has no other means to achieve a mutual national security objective of destroying Iran’s underground nuclear infrastructure or facilities; and
a dual key control system is in place requiring approval by the President, acting through the Secretary of Defense (which may not be further delegated) for deployment of the MOP or related munitions described in paragraph (1) prior to Israeli deployment of such munitions.
To provide for training of Israeli personnel with respect to the MOP or related munitions described in paragraph (1).
To conduct joint research and development with Israel to—
enhance United States ordnance; and
develop Israeli capability for ordnance to destroy underground infrastructure, including Hezbollah rocket storage and manufacturing facilities and underground Iranian nuclear facilities.
In this section, the term NPT Safeguards Agreement
means the Agreement between Iran and the International Atomic Energy Agency for the Application of Safeguards in Connection with the Treaty on the Non-Proliferation of Nuclear Weapons, which entered into force on May 15, 1974.
Nothing in this Act may be construed to serve as an authorization for the use of military force against Iran.