By Eric Buesing
Here is what the press releases did not mention. The SPR currently holds about 415 million barrels.⁶ After this drawdown it will hold roughly 243 million barrels, the lowest level since the reserve was first being filled in the late 1970s. And the physical infrastructure that holds this oil, 60 underground caverns carved into ancient salt formations beneath the Gulf Coast of Texas and Louisiana, was engineered from the beginning for approximately five full drawdown cycles per cavern.⁷
Some of those caverns are running out of cycles.
What You’re Actually Picturing Is Wrong
When most people imagine an oil reserve, they picture a tank. Maybe an enormous one, but still a tank, a steel container somewhere above ground. The SPR is nothing like that. The federal government stores its emergency crude inside the earth itself, in caverns it created by drilling down into salt domes and pumping in fresh water. The water dissolves the salt, and the resulting hollow space becomes a storage vessel, sealed by millions of tons of rock above it. The caverns are staggering in scale: a typical one holds 10 million barrels, measures roughly 200 feet in diameter, and runs 2,500 feet deep, large enough that the Willis Tower in Chicago could fit inside with room to spare.⁸
Getting the oil back out works on a beautiful, low-tech principle. Oil floats on water. To retrieve the crude, engineers pump fresh water into the bottom of the cavern. The water pushes the oil upward and out through a pipe at the top, where it travels to refineries across the Gulf Coast. Simple. Elegant. Almost free to operate once built.
Almost free is the key phrase.
Every time that fresh water is pumped in to retrieve the oil, it doesn’t just displace what’s stored. It keeps dissolving the salt walls. The cavern grows slightly larger. The walls thin slightly. The salt pillars separating one cavern from its neighbor lose a little more material. Do this enough times and the structural integrity of the whole system begins to degrade in ways that cannot be repaired.⁹
This is what a geologist would call “drawdown leaching,” and it is the central engineering constraint that has governed the SPR since the day it was built. It is also something that has been almost entirely absent from public discussion about how the reserve gets used, including yesterday’s announcement.
The Five-Drawdown Problem
When the government designed the SPR in the mid-1970s, engineers established a baseline: these caverns were built for approximately five full drawdown cycles. Not fifty. Not unlimited. Five.¹⁰
Some caverns have even fewer. Sandia National Laboratories, which monitors SPR cavern integrity for the Department of Energy on an ongoing basis, has confirmed in published reports that certain individual caverns should only be completely drawn down a single time. After that, further drawdowns risk compromising what engineers call the “pillar-to-diameter ratio,” essentially whether enough solid salt remains between caverns to keep the whole structure stable.¹¹
Think of it like the old mining towns of the American West, where coal was extracted from underground for decades until the ground above started to sink. Buildings would tilt. Sinkholes would open. The SPR caverns are deep enough and well-built enough that catastrophic collapse is not the immediate worry, but the concern is real enough that Sandia produces an annual report tracking exactly how many full drawdowns each of the 60 caverns has remaining.¹²
That report is not widely read outside of government circles.
There is already a historical warning baked into the SPR’s own record. One of its original sites, Weeks Island in Louisiana, was a conventional salt mine decommissioned in 1999 after a sinkhole formed on the surface, allowing fresh water to seep in. Because the whole facility was built in salt, that fresh water slowly eroded the ceiling. The government had to carefully extract the oil and fill the mine with brine to prevent collapse. Weeks Island held 72 million barrels of crude. It is gone now, permanently.¹³
A Bipartisan History of Spending the Principal
The degradation of the SPR is not the project of any one party or president. It is the accumulated result of decades of decisions by administrations of both parties, each with different justifications, most of them at least partly political.
The reserve was created in 1975, after the 1973 Arab oil embargo created gas lines around American city blocks and a genuine national sense of vulnerability. The idea was simple: store enough oil underground that if supplies were ever cut off again, the country could keep running for months while it figured out what to do. First oil was delivered in 1977. It took more than three decades to fill the caverns to their peak of 727 million barrels, reached in December 2009.¹⁴
Since then, the story has been largely one of depletion.
The George W. Bush administration used the SPR after Hurricane Katrina in 2005. Congress, across multiple administrations of both parties, repeatedly authorized mandated sales from the reserve as a budget mechanism, not because of any energy emergency, but because selling oil generated revenue that could be used to offset spending elsewhere. The Congressional Budget Office found that Congress raised $18.3 billion in such “offsets” through 2025 by simply writing SPR drawdowns into spending legislation. The oil was sold. The caverns were partially emptied. The money went to other things. No one appropriated funds to refill them.¹⁵
Then came the Biden administration’s 2022 release, the largest single drawdown in SPR history up to that point. In response to rising gas prices following Russia’s invasion of Ukraine, 180 million barrels were authorized in a single order. By the time all drawdowns across Biden’s term were tallied, roughly 300 million barrels had been removed between 2021 and 2024. The SPR fell to its lowest level since 1983.¹⁶
Now, less than two years after Trump took office having criticized Biden’s drawdown sharply,¹⁷ the Trump administration has authorized a comparable release of 172 million barrels. The justification this time is a genuine shooting war disrupting global oil supply, which is a more defensible trigger. But the caverns do not know the difference between a politically motivated release and a military one. The walls thin either way.
The Math Nobody Is Saying Out Loud
Before yesterday’s announcement, the SPR held approximately 415 million barrels. The planned release is 172 million barrels, to be delivered over approximately 120 days beginning next week.¹⁸ When that drawdown is complete, the reserve will hold roughly 243 million barrels. The authorized maximum capacity is 714 million barrels.¹⁹ We will be sitting at 34 percent of capacity.
The government has promised to replace the oil with 200 million barrels “within the next year, at no cost to the taxpayer.”²⁰ If that happens, the reserve climbs back to around 443 million barrels, still only 62 percent of capacity, and still carrying the structural wear of yet another full drawdown cycle across dozens of caverns.
That promised replenishment depends on oil prices falling to a level where buying back makes economic sense, on Congress appropriating the necessary funds, and on the physical infrastructure being in good enough shape to accept the oil. On that last point, Energy Secretary Wright acknowledged earlier this year that recent drawdowns have already caused structural damage to SPR facilities requiring $100 million in repairs.²¹ The Life Extension II modernization program, authorized by Congress in 2015 with $1.4 billion to extend the system’s operational lifespan by 15 to 25 years, has faced delays, cost overruns, and a documented funding gap of at least $500 million.²²
What It Would Cost to Replace This System
The salt caverns of the Gulf Coast are not replaceable in any practical sense, at least not quickly and not cheaply. What makes them so valuable is a specific combination of geography, geology, and infrastructure that took decades to develop. They sit directly adjacent to the largest concentration of oil refineries in the United States, connect to a web of interstate pipelines, and exist in the kind of salt dome geology that makes solution mining possible. They are also deep enough to benefit from what the Department of Energy describes as “self-healing” salt properties: extreme underground pressure causes any micro-cracks to close almost immediately on their own.²³
Once a cavern has been drawn down too many times and its walls have thinned past safe tolerances, it cannot be rebuilt. The salt that dissolved into brine and was piped offshore into the Gulf of America is gone. There is no way to put it back.
So what happens if the United States loses significant cavern capacity? The alternatives exist, but none of them are good.
Aboveground steel tank farms are the most obvious option, and the technology is proven. The problem is cost and vulnerability. Storing one barrel of crude oil in a surface tank costs roughly $15 to $18. In the salt caverns, the same barrel costs approximately $1.50, about ten times cheaper.²⁴ Replacing even a fraction of the SPR’s capacity with surface tanks would require tens of billions of dollars in construction and hundreds of millions per year in maintenance. And above-ground tanks are targets. They burn. They can be attacked. The whole strategic logic of hiding the reserve underground disappears entirely.
Depleted oil and gas fields are already used for large-scale natural gas storage across the country and represent a plausible option for crude. They account for 78 percent of total underground natural gas storage capacity in the United States.²⁵ The challenge is location: the best depleted fields are scattered across the interior of the country, far from the Gulf Coast refineries that need rapid access to crude in an emergency.
Hard rock cavern mining, used in some European countries, costs approximately $30 per barrel to develop, roughly 20 times more expensive than salt cavern storage.²⁶ It is not a realistic large-scale option for the United States.
New salt caverns could be solution-mined in additional Gulf Coast salt domes. This is probably the most logical long-term backup strategy. It works, it is proven, and the geology exists. But it takes years to develop a cavern to full size, and you cannot build one in a hurry during a crisis. Certainly not during one that is already underway.
The Number That Should Alarm People
When this drawdown is complete, the United States will hold roughly 243 million barrels of emergency crude. The country consumes approximately 20.25 million barrels of petroleum and petroleum products per day.²⁷ That is roughly 12 days of total consumption sitting underground.
The government will note, correctly, that “days of net import protection” is a more relevant measure, since the United States now produces approximately 13.5 million barrels per day domestically.²⁸ That calculation produces a more reassuring number. But what is happening in the Strait of Hormuz right now is a reminder that “net imports” is a peacetime metric. In a genuine supply disruption, whether a major conflict, a catastrophic hurricane season, or a serious attack on Gulf infrastructure, what matters is how long the country can run if the pipes stop flowing. On that measure, 12 days is not a comfortable margin for the world’s largest economy.
And that does not account for the structural degradation question at all. The annual Sandia reports tracking remaining drawdowns per cavern are not documents that make headlines. But they exist, they are updated every year, and the number of available cycles they document keeps declining.
What Happens Next
Energy Secretary Wright says the released oil will be replaced with 200 million barrels “within the next year, at no cost to the taxpayer.” The administration has not fully explained the mechanism for how this happens at no taxpayer cost while simultaneously prosecuting a war that has already sent oil prices past $100 per barrel.²⁹ Brent crude was trading above $91 on the day of the announcement and the EIA’s own March 2026 Short-Term Energy Outlook projects prices averaging $91 per barrel through the second quarter.³⁰ Replacing oil sold at crisis prices, by buying at crisis prices, is not obviously a good deal.
President Trump has said the administration will also refill the SPR to full capacity after the crisis passes.³¹ That ambition has been a stated priority since his inaugural address in January 2025. It would require approximately $20 billion in appropriations, cavern infrastructure capable of holding it, and an oil market calm enough to buy at a reasonable price.³² Right now, none of those three conditions are clearly in place.
The United States built something remarkable underneath the Gulf Coast. A geological battery, essentially, charged over decades with accumulated crude against the day the country might desperately need it. The engineering is remarkable. The salt formations that hold this oil are hundreds of millions of years old. Under the right conditions they can hold liquid cargo for decades without leaking a drop.
Those conditions require that you not empty and refill them too many times. They require maintenance funding that Congress has repeatedly treated as optional. They require long-term stewardship in a political system that runs on two-year election cycles managing a 50-year asset.
The war in Iran is a legitimate emergency. Using the SPR for it is exactly what the SPR is for. But the caverns that will begin emptying next week have already been through this before, multiple times, under multiple presidents, for reasons ranging from genuine national security to budget gimmicks to midterm election math. Each time, the promise was that the oil would be replaced. Each time, replacement happened slowly if at all. Each time, the structural wear on the caverns quietly accumulated.
The account is being opened again. The question that nobody in Washington seems particularly eager to answer out loud is how many times that is still possible.
Eric Buesing, MBA, is an independent researcher, historian, and author whose work delves into the hidden mechanisms of power, wealth, and control throughout human history.
With a keen focus on philosophy, consciousness, and the transformative potential of blockchain technology, particularly the concept of the “Internet of Value.” Eric challenges readers to uncover deep truths and resist manipulative forces shaping society. His forthcoming book, The Hidden Hand: Wealth, Power, and Control from Pharaohs to Corporations (set for publication June 2026), traces 5,000 years of elite strategies, from ancient coercion tactics to modern corporate and transhumanist influences in warning against the erosion of human potential. Eric is an avid blogger and advocate for individualized education, fostering critical inquiry and interdisciplinary dialogue. He shares his insights on ericbuesing.com, Substack at sleuthfox.substack.com and X (@sleuthfox), where he explores historical amnesia, and the intersection of technology and human freedom.
Notes
¹ U.S. Department of Energy, “United States to Release 172 Million Barrels of Oil from the Strategic Petroleum Reserve,” statement by Secretary Chris Wright, March 11, 2026, https://www.energy.gov/articles/united-states-release-172-million-barrels-oil-strategic-petroleum-reserve.
² International Energy Agency, “Strait of Hormuz: Oil Security and Emergency Response,” IEA, 2026, https://www.iea.org/about/oil-security-and-emergency-response/strait-of-hormuz. The IEA reports that an average of 20 million barrels per day of crude oil and oil products transited the Strait in 2025, representing approximately 25 percent of world seaborne oil trade. See also U.S. Energy Information Administration, “Amid Regional Conflict, the Strait of Hormuz Remains Critical Oil Chokepoint,” *Today in Energy*, June 2025, https://www.eia.gov/todayinenergy/detail.php?id=65504.
³ Patrick De Haan, quoted in CBS News, “Strait of Hormuz Ship Traffic Slows to a Crawl,” March 9, 2026, https://www.cbsnews.com/news/strait-of-hormuz-iran-oil-prices-us.
⁴ *The National News*, “US to Release 172 Million Barrels from Strategic Petroleum Reserve,” March 12, 2026, https://www.thenationalnews.com/news/us/2026/03/12/us-to-release-172-million-barrels-from-strategic-petroleum-reserve.
⁵ International Energy Agency, “The Middle East and Global Energy Markets,” IEA, March 2026, https://www.iea.org/topics/the-middle-east-and-global-energy-markets. The IEA confirms that on March 11, 2026, member countries unanimously agreed to carry out the Agency’s largest-ever release of emergency oil stocks.
⁶ U.S. Department of Energy, *SPR Quick Facts*, January 2026, https://www.energy.gov/hgeo/opr/spr-quick-facts. The DOE reports 411 million barrels at end of calendar year 2025; the figure of approximately 415 million barrels reflects subsequent minor acquisition deliveries as reported by the DOE and CNBC as of the announcement date.
⁷ National Maritime Foundation, “Crude-Oil Storage in an Era of Plenty, Part 2: Lessons from the USA’s Strategic Petroleum Reserve,” October 2020, https://maritimeindia.org/crude-oil-storage-in-an-era-of-plenty-part-2-lessons-from-the-usas-strategic-petroleum-reserve, citing John Shages, “The Strategic Petroleum Reserve,” 6.
⁸ U.S. Department of Energy, “SPR Storage Sites,” https://www.energy.gov/hgeo/opr/spr-storage-sites.
⁹ Sandia National Laboratories, *Analysis of Strategic Petroleum Reserve (SPR) Small-Scale Cavern Drawdowns*, OSTI ID 6412370, 1985, https://www.osti.gov/biblio/6412370. See also David B. Hart, Todd Zeitler, and Steven R. Sobolik, *2022 Annual Report of Available Drawdowns for Each Oil Storage Cavern in the Strategic Petroleum Reserve*, SAND2022-7276 (Albuquerque, NM: Sandia National Laboratories, 2022), https://www.osti.gov/biblio/1870557.
¹⁰ National Maritime Foundation, “Crude-Oil Storage in an Era of Plenty, Part 2,” citing John Shages, “The Strategic Petroleum Reserve,” 6; see also Hart, Zeitler, and Sobolik, *2022 Annual Report of Available Drawdowns*, which establishes five drawdowns as the engineering baseline.
¹¹ David B. Hart, *2023 Annual Report of Available Drawdowns for Each Oil Storage Cavern in the Strategic Petroleum Reserve*, SAND2023-00702 (Albuquerque, NM: Sandia National Laboratories, 2023), doi:10.2172/1973473, https://www.osti.gov/biblio/1973473.
¹² Ibid.
¹³ “Strategic Petroleum Reserve (United States),” *Wikipedia*, last modified January 6, 2026, https://en.wikipedia.org/wiki/Strategic_Petroleum_Reserve_(United_States). The Weeks Island decommissioning is documented in DOE records and summarized in this entry; the 72-million-barrel capacity and 1999 closure are consistent across DOE and Congressional Research Service sources cited herein.
¹⁴ U.S. Department of Energy, *SPR Quick Facts*.
¹⁵ Congressional Budget Office figures cited in National Taxpayers Union Foundation, “Politics Drained the Strategic Petroleum Reserve, Reforms Can Refill It Without Soaking Taxpayers,” October 2, 2025, https://www.ntu.org/foundation/detail/politics-drained-the-strategic-petroleum-reserve-reforms-can-refill-it-without-soaking-taxpayers.
¹⁶ National Taxpayers Union Foundation, “Politics Drained the Strategic Petroleum Reserve.” See also “Strategic Petroleum Reserve (United States),” *Wikipedia*.
¹⁷ Axios, “Trump to Release Strategic Petroleum Reserve to Counter Iran War Oil Shock,” March 11, 2026, https://www.axios.com/2026/03/11/trump-strategic-oil-reserve-gas-prices-iran-war. The piece notes that former President Biden sold more than 40 percent of the reserve in 2022, prompting Republican criticism that the drawdown left the U.S. vulnerable to supply disruptions.
¹⁸ U.S. Department of Energy, “United States to Release 172 Million Barrels.”
¹⁹ U.S. Department of Energy, “SPR Storage Sites.”
²⁰ U.S. Department of Energy, “United States to Release 172 Million Barrels.”
²¹ National Taxpayers Union Foundation, “Politics Drained the Strategic Petroleum Reserve,” citing Secretary Wright’s testimony before the House Energy and Commerce Subcommittee on Energy.
²² U.S. Department of Energy, *FY 2026 Congressional Budget Request, Volume 3: Strategic Petroleum Reserve*, June 2025, https://www.energy.gov/sites/default/files/2025-06/doe-fy-2026-vol-3-spr-v1.pdf. The document states that SPR-LE2 completion will extend key equipment and infrastructure capabilities for an additional 15 to 25 years; the $500 million funding gap reflects additional supplemental funding requests documented therein. See also Congressional Research Service, “Energy and Water Development: FY2025 Appropriations,” R48097, https://www.congress.gov/crs-product/R48097.
²³ U.S. Department of Energy, “SPR Storage Sites.”
²⁴ Scientific analysis of salt cavern storage costs cited in Yiteng Wang et al., “Oil Recovery and Cooling for Underground Salt Cavern Oil Storage,” *Journal of Energy Storage* (2024), https://www.sciencedirect.com/science/article/abs/pii/S2949891024008261. Storage cost figures of approximately $1.50 per barrel for salt caverns versus $15 to $18 for surface tanks are consistent across multiple engineering sources; see also U.S. Department of Energy, “SPR Storage Sites” (noting salt caverns are “up to ten times more cost effective” than aboveground storage).
²⁵ U.S. Energy Information Administration, “The Basics of Underground Natural Gas Storage,” https://www.eia.gov/naturalgas/storage/basics.
²⁶ Wang et al., “Oil Recovery and Cooling.”
²⁷ U.S. Energy Information Administration, “How Much Oil Is Consumed in the United States?,” *FAQs*, last updated October 2024, https://www.eia.gov/tools/faqs/faq.php?id=33&t=6. The EIA reports U.S. petroleum consumption averaged 20.25 million barrels per day in 2023; 2024 figures from Statista/EIA report 20.45 million barrels per day.
²⁸ U.S. Energy Information Administration, “EIA Forecasts U.S. Crude Oil Production Will Decrease Slightly in 2026,” *Today in Energy*, https://www.eia.gov/todayinenergy/detail.php?id=66844.
²⁹ *The National News*, “US to Release 172 Million Barrels.”
³⁰ U.S. Energy Information Administration, *Short-Term Energy Outlook*, March 2026, https://www.eia.gov/outlooks/steo/report/global_oil.php.
³¹ CNBC, “Iran War: Trump Will Release 172 Million Barrels of Oil from Strategic Petroleum Reserve,” March 11, 2026, https://www.cnbc.com/2026/03/11/iran-war-trump-oil-strategic-petroleum-reserve.html.
³² Congressional Research Service, “Strategic Petroleum Reserve: Inventory Outlook and Policy Considerations,” IN12542, updated 2025, https://www.everycrsreport.com/reports/IN12542.html.
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