The U.S. Strategic Petroleum Reserve fell to 298.7 million barrels in the week ending in early August, its lowest level since January 1983, according to Department of Energy data. Inventories declined by 6.1 million barrels during the week, continuing a drawdown that began in March amid disruptions to oil shipments through the Strait of Hormuz.
President Donald Trump authorized the release of up to 172 million barrels on March 11, 2026, in response to energy-market pressures linked to the Iran war and attacks affecting tanker traffic. The reserve held about 415.4 million barrels in mid-March, meaning stocks had dropped by roughly 116 million barrels by early August.
The latest withdrawals follow a larger decline that started in 2022, when the Biden administration authorized a 180 million-barrel release after Russia invaded Ukraine. SPR inventories fell from about 600 million barrels at the beginning of 2022 to 375 million by year-end. They later recovered, reaching 400 million in May 2025 and more than 415 million in February 2026.
Established in 1975 after the 1973-74 OPEC oil embargo, the SPR was designed to protect the country from major supply interruptions. Although initially envisioned to hold 1 billion barrels, its current authorized capacity is approximately 714 million. Its record inventory was 726.6 million barrels in December 2009.
The oil is stored in four underground salt-cavern sites, which offer cost, maintenance, environmental and security advantages over surface facilities. Natural geological pressure helps seal cracks, while temperature differences circulate the crude and preserve its quality. In May, the Government Accountability Office called for Congress and the Energy Department to create a coordinated long-term plan for maintenance and inventory management. Legislation enacted in July 2025 provided $171 million to purchase petroleum for the reserve and $218 million for maintenance as policymakers assess future national emergency energy needs.