Behind the news:
America’s emergency oil vault: A history of the Strategic Petroleum Reserve
Surface pipelines, processing towers and storage equipment at the Strategic Petroleum Reserve facility in West Hackberry, La., are shown in this file photo. The reserve, which stores crude oil in underground salt caverns along the Gulf Coast, fell below 300 million barrels on Aug. 10, 2026 — its lowest level since January 1983. Photo by: U.S. Department of Energy via AP
Wednesday, Aug. 12, 2026 | 2 a.m.
Editor’s note: “Behind the News” is the product of Sun staff assisted by the Sun’s AI lab, which includes a variety of tools such as Anthropic’s Claude and Google Gemini.
The underground chambers along the Gulf Coast hold no treasure in the conventional sense — no gold, no silver, nothing that gleams. What they hold is crude oil, hundreds of millions of barrels of it, salted away in massive salt caverns carved into the earth beneath Texas and Louisiana. Or at least they used to.
The U.S. Strategic Petroleum Reserve, the world’s largest government-owned emergency oil stockpile, fell below 300 million barrels Monday — a milestone that underscores just how dramatically America has drawn on its most critical energy insurance policy in recent years.[1] The reserve, which once held 726 million barrels at its 2009 peak, now sits at levels not seen since January 1983 — less than half full and aging under the strain of repeated, unprecedented drawdowns.[2]
The forces that drained it are a product of both crisis and politics — foreign wars, natural disasters, congressional budget maneuvers and, in the most recent case, the U.S.-Iran conflict and its stranglehold on one of the world’s most critical oil shipping lanes.
Born of embargo
The reserve’s origins trace to one of the most jarring economic shocks in modern American history: the Arab oil embargo of 1973-74. In October 1973, the Organization of Arab Petroleum Exporting Countries imposed a cutoff of oil to the United States in retaliation for American support of Israel during the Yom Kippur War. The price of imported crude oil shot from roughly $4 a barrel during the last quarter of 1973 to an average of $12.50 a barrel in 1974. Gas lines stretched for blocks across America. The U.S. economy lurched into recession.[3]
The idea of a strategic oil reserve was not new. Secretary of the Interior Harold Ickes had advocated it in 1944. President Harry Truman’s Minerals Policy Commission proposed one in 1952. President Dwight Eisenhower suggested it after the 1956 Suez Crisis. But the embargo made the argument impossible to ignore.[4]
President Gerald Ford signed the Energy Policy and Conservation Act on Dec. 22, 1975, directing the federal government to build an emergency crude oil stockpile.[5] Around the same time, the United States joined the International Energy Agency, a consortium with the mission to ensure a quick and effective response to energy supply disruptions.[2]
Congress authorized a capacity of up to 1 billion barrels — though in 1978 it set the physical storage target at 750 million barrels, and it never appropriated funds to reach the full 1 billion barrel level — and designated the Department of Energy to manage the reserve.[7]
How it was built
The government moved quickly. By April 1977, it had acquired its first salt caverns along the Gulf Coast. On July 21, 1977, the first oil — approximately 412,000 barrels of Saudi Arabian light crude — arrived at the West Hackberry storage site near Lake Charles, La., pumped into the earth at what would become one of the four storage complexes that make up the reserve.[4]
The other sites are Bryan Mound and Big Hill in Texas, and Bayou Choctaw in Louisiana. Together, they encompass 61 underground salt caverns that can hold a combined 714 million barrels.[9]
The choice of salt caverns was deliberate. Salt formations are naturally impermeable, making them ideal for long-term storage. The Gulf Coast location placed the reserve close to the nation’s largest concentration of oil refineries, interstate pipelines and marine terminals, allowing oil to reach the market within 13 days of a presidential decision.[9]
What goes into those caverns is crude oil — specifically, crude oil that meets DOE quality specifications, categorized as either “sweet” (sulfur content of no more than 0.5% by weight) or “sour” (sulfur content greater than 0.5% and less than 2.0%). The mix is intentional: roughly 40% sweet and 60% sour, calibrated to match the needs of American refineries that process both grades. The SPR stores crude oil rather than refined products such as gasoline or diesel — a deliberate policy judgment made in 1977, based on an assessment that U.S. refining capacity was robust enough to handle conversion needs.[9]
The average price paid by the U.S. — reflecting the early years of fill when oil was far cheaper — has been about $29.70 a barrel. The U.S. government has spent roughly $25.7 billion on the reserve in total, about $5 billion for facilities and $20.7 billion for crude oil.[9]
How it gets filled — and drained
Filling the SPR is a federal purchase process: DOE buys oil on the open market using appropriated funds or revenue from previous sales and injects it into the caverns by pumping seawater in to displace the oil upward and out. Running the process in reverse — pumping water into the bottom of the cavern — pushes the stored oil back to the surface and into distribution pipelines.[15]
DOE also manages “exchange agreements,” in which private companies borrow oil from the reserve in a supply emergency — a pipeline disruption, a hurricane — and are contractually required to return it, with interest in the form of additional barrels.[15]
When the president orders a drawdown, DOE auctions the crude to U.S. companies at competitive bid. The proceeds flow into the SPR Petroleum Account, designated for future oil purchases. When Congress mandates a sale for other purposes, the revenue typically goes to the general fund of the Treasury.[15]
Filling the reserve slowed and stopped several times over the decades, often at the direction of Congress. The reserve did not reach capacity until 2009, when a final shipment of 493,000 barrels of Saharan Blend crude was delivered to the Bryan Mound site. It was the culmination of more than 30 years of fitful, sometimes politically fraught accumulation.[9]
A history of drawdowns
Despite its name, the Strategic Petroleum Reserve has not always been used exclusively for strategic emergencies.
• The Gulf War, 1991: The first-ever emergency drawdown came in January 1991, when President George H.W. Bush ordered the release of SPR crude in coordination with IEA partners at the start of Operation Desert Storm. Iraq’s invasion of Kuwait had disrupted oil markets. The announcement alone helped stabilize prices. Energy Secretary James Watkins accepted only bids above 97.5% of benchmark prices, and in practice just 17.3 million of the 33.75 million barrels authorized were actually sold.[19]
In the aftermath, Watkins signaled an important lesson was learned through the situation, saying, "We have sent an important message to the American people that their $20 billion investment in an emergency supply of crude oil has produced a system that can respond rapidly and effectively to the threat of an energy disruption."[19]
• Hurricane Katrina, 2005: When Hurricane Katrina struck the Gulf Coast on Aug. 29, 2005, it crushed oil production facilities, distribution networks and refineries across Louisiana and Mississippi. President George W. Bush authorized the drawdown Sept. 2, 2005, and emergency releases totaling about 30 million barrels followed. Hurricane Rita, which struck weeks later, prompted additional loans.[20]
• Libya and the IEA, 2011: In June 2011, the United States and its IEA partners released a combined 60 million barrels in response to the disruption of Libyan crude exports during that country’s civil war. The U.S. contribution was approximately 30 million barrels. [21]
• The congressional piggy bank, 2015 onward: Beginning in 2015, Congress discovered that SPR sales could be a useful budget tool. Because oil sale proceeds are counted in the federal budget as “offsetting receipts” — essentially negative spending — lawmakers began mandating SPR drawdowns to help finance higher spending while making legislation appear deficit-neutral on paper.
Since 2015, Congress has enacted eight laws that together would have mandated the sale of 358.6 million barrels between fiscal 2017 and fiscal 2031. Sales were authorized under the Bipartisan Budget Act of 2015, the Fixing America’s Surface Transportation Act (2016), the 21st Century Cures Act (2016), the Tax Cuts and Jobs Act (2017) and the Bipartisan Budget Act of 2018, among others.[22]
Critics called it treating the reserve as a legislative ATM. In December 2022, as the reserve reached its lowest point in decades, Congress reversed course and canceled several planned future sales to prevent further drawdown.[23]
• Ukraine and Biden, 2022: A consequential drawdown before the present crisis came after Russia invaded Ukraine in February 2022. President Joe Biden authorized the release of 180 million barrels — the largest emergency sale in the reserve’s history at that time — at a rate of 1 million barrels per day for 180 days. Oil sold at an average of $96 a barrel, generating roughly $17.2 billion in proceeds for the SPR Petroleum Account. The release drew the reserve to levels not seen since the mid-1980s.[23]
The Biden administration began replenishing the reserve after oil prices fell, ultimately purchasing 59 million barrels and, in November 2024, finalizing a deal to secure nearly 200 million barrels through a combination of purchases and cancellation of congressionally directed future sales. But the administration never fully made up the deficit before leaving office.[2]
• The Iran crisis and a new low: The reserve’s current predicament stems from the ongoing Iran crisis. Following U.S. and Israeli military strikes against Iran, Tehran moved to choke off oil exports through the Strait of Hormuz — a waterway that carries roughly 25% of the world’s seaborne oil supply. The closure triggered the largest disruption of crude flows in history.[2]
On March 11, the Trump administration announced DOE would release 172 million barrels from the reserve over approximately 120 days — the U.S. share of a 400 million-barrel release coordinated across 32 International Energy Agency member nations. Structured as an exchange rather than an outright sale, the releases required companies borrowing oil to return between 18% and 28% more than they took.[27]
The releases helped blunt the market impact. Oil prices jumped significantly from the start of the conflict but did not reach the record highs that some energy analysts had predicted, as SPR oil, commercial inventories and reduced consumer demand collectively softened the blow.[2]
But as of last week, the reserve had fallen to 298.7 million barrels — below 300 million for the first time in more than four decades, and less than 43% of total capacity.[29]
Infrastructure under strain
The physical condition of the reserve adds an additional layer of concern. A May report from the Government Accountability Office found that more than a quarter of the SPR’s inventory was “not available for drawdown due to a combination of construction outages and cavern outages” as of December 2025. An analysis by Rapidan Energy estimated that at least 103 million barrels of the current inventory are inaccessible for use.[30]
The GAO warned that the reserve’s infrastructure is aging and at risk. Sandia National Laboratories, which serves as the geotechnical adviser to the SPR, found in 2024 that well deformations were outpacing DOE’s ability to address the risk of potential well failures. The GAO further noted that DOE and Congress lack a unified long-term plan for the reserve — no agreed target size, no defined investment roadmap.[31]
“The SPR’s drawdown, distribution and fill capabilities are currently limited and are at risk going forward due to longstanding issues with aging infrastructure compounded with ongoing major construction intended to address them,” the GAO stated.[32]
The Energy Department has set a minimum operating floor of roughly 70 million barrels — the point at which the reserve could no longer be safely operated — leaving a buffer that, while still substantial, is shrinking.[32]
Steve Hanke, a professor of applied economics at Johns Hopkins University, said: “At 311.4 million barrels, the lowest level since 1983, the SPR cannot sustain repeated drawdown cycles without approaching dangerously low levels.” [31]
What comes next
President Donald Trump said at his January 2025 inauguration that his administration intended to fill the reserve to capacity, and a February 2025 DOE secretarial order listed refilling the reserve as a department priority.[35] The current drawdown has complicated that goal considerably.
Refilling the reserve is a slow, expensive process. At current levels, reaching even 600 million barrels would require purchasing and injecting hundreds of millions of barrels of crude at today’s prices — prices that have risen substantially since the Iran conflict began.[35] And the physical infrastructure to receive and store that oil remains compromised by deferred maintenance and ongoing construction.
The reserve was created on the premise that the United States would always have time to rebuild before the next crisis arrived. The pace of recent events has challenged that assumption.
Since the reserve’s creation five decades ago, more than 500 million barrels have been released from it — with nearly 70% of those releases occurring between 2014 and 2025 alone.[37] What took 30 years to fill has been substantially emptied in roughly a decade, through a combination of emergencies, budget politics and geopolitical crises that the Energy Policy and Conservation Act of 1975 was never designed to anticipate.
The underground chambers along the Gulf Coast still hold crude oil. But not as much as they once did — and, by the government’s own accounting, not as much as the country may need.
Sources
[2] https://bipartisanpolicy.org/explainer/how-the-u-s-strategic-petroleum-reserve-works/
[3] https://www.congress.gov/crs_external_products/R/PDF/R42460/R42460.16.pdf
[4] https://www.energy.gov/hgeo/opr/spr-origins
[5] https://www.energy.gov/node/2631540
[7] https://www.energy.gov/hgeo/opr/filling-strategic-petroleum-reserve
[9] https://www.energy.gov/hgeo/opr/spr-quick-facts
[15] https://bipartisanpolicy.org/explainer/how-the-u-s-strategic-petroleum-reserve-works/
[19] https://www.energy.gov/hgeo/opr/history-spr-releases
[20] https://www.everycrsreport.com/reports/RL33124.html
[23] https://www.dallasfed.org/research/economics/2023/1003
[27] https://marketwise.com/investing/strategic-petroleum-reserve-43-year-low-refill-oil-prices/
[35] https://www.congress.gov/crs-product/IN12542
[37] https://mansfield.energy/2026/07/02/strategic-petroleum-reserve-falls-to-lowest-level-since-1983/