America’s emergency oil stockpile has fallen below 300 million barrels for the first time since the Strategic Petroleum Reserve was filled in the early 1980s. Now, some energy experts are warning that the problem may go far beyond simply having less oil available during the next crisis.
The rapid drawdown could threaten the underground salt caverns that hold the crude, potentially reducing how quickly the United States can respond to another major supply disruption. The warnings come as the U.S. releases 172 million barrels from the Strategic Petroleum Reserve, or SPR, in response to supply disruptions caused by the Iran war. When the current drawdown is complete, the reserve is expected to contain only about 243 million barrels.
That would put the SPR below what some experts consider its practical operating floor and raise new questions about the long-term viability of one of the country’s most important energy-security assets.
The Reserve Is Heading Into Uncharted Territory
The Strategic Petroleum Reserve was created after the oil shocks of the 1970s to give the United States a massive emergency supply of crude that could be released when wars, natural disasters or other disruptions threaten energy supplies. At its peak, the reserve held more than 700 million barrels.
Its oil isn’t stored in conventional above-ground tanks. Instead, crude is held thousands of feet underground inside roughly 60 enormous salt caverns at four major sites along the Gulf Coast in Texas and Louisiana.
Those caverns are now becoming a growing source of concern as inventories fall to levels not seen in more than four decades. The Department of Energy has said at least 70 million barrels must remain in the reserve to safely manage the caverns, but several energy experts argue that number represents a physical minimum rather than a realistic level at which the system could continue operating normally.
Former Biden administration energy adviser Amos Hochstein has been particularly critical of the 70-million-barrel figure.
“Don’t believe the people out of the government that are saying the SPR can go to 70 million barrels. It’s nonsense,” Hochstein told CNBC. He argued that taking the reserve that low could deplete it to the point where fully restoring its capabilities becomes extraordinarily difficult.
Hochstein had already warned in June that dropping below 300 million barrels could put the storage system itself at greater risk. “I don’t know anyone who believes we can go below 300,” he said at an Atlantic Council event, adding that some experts believe approaching that level could physically damage the caverns where the oil is stored.
Energy Department Pushes Back
The Department of Energy strongly disputes claims that the storage caverns face collapse as oil is withdrawn.
Energy Department spokesman Ben Dietderich said the caverns remain full because water replaces the oil removed from them. “The caverns are always full. All that changes is the ratio of oil and water that is filling them,” Dietderich told CNBC, adding that the Trump administration is “responsibly managing the SPR as the critical national security asset it was designed to be.”
But the mechanics of replacing that oil are precisely what concern some engineers. Extracting crude from the SPR involves pumping water into the bottom of a cavern, which pushes the oil upward and allows it to travel through wells into pipelines.
The problem is that fresh water dissolves salt. During repeated and rapid drawdowns, that process can gradually alter the shape and dimensions of the underground caverns, potentially creating problems that accumulate over decades of use.
Why Repeated Drawdowns Matter
The Government Accountability Office warned in a May report that repeated partial drawdowns followed by refilling can repeatedly leach the same portions of a cavern, potentially creating “undesirable shapes.”
The GAO found that most SPR caverns remained in “very good condition” following the massive 2022 drawdown. However, the watchdog also highlighted a longer-term structural concern: every drawdown cycle expands cavern volume and reduces the spacing between neighboring caverns inside the salt dome, which ultimately reduces their long-term viability.
That matters because the SPR has been used far more frequently than originally envisioned. Siddharth Misra, a petroleum engineering professor at Texas A&M University, said the reserve was originally designed around approximately five full drawdowns but has instead experienced dozens of large and small releases during its roughly four decades of operation.
According to Misra, repeated injections of water and extractions of oil have contributed to cavern deformation and salt falls from cavern ceilings while weakening the aging storage system over time. Rapid withdrawals can be particularly problematic because large quantities of fresh water must be injected to push the crude toward the surface.
Misra warned that the process can create flatter, less stable cavern roofs while thinning the salt pillars separating neighboring caverns. In a worst-case scenario, those changes could increase the geological risk of structural problems.
The Critical 250 Million to 300 Million Barrel Range
Misra estimates that the practical operational floor for the SPR is somewhere between 250 million and 300 million barrels. At current inventory levels, he said cavern integrity and the reserve’s overall operational capabilities face elevated risks.
That makes the projected post-drawdown level especially significant. Once the current 172-million-barrel release is completed, the SPR is expected to contain approximately 243 million barrels, putting it below the lower end of Misra’s estimated practical operating range.
Other analysts believe the reserve has more room before reaching a critical threshold. Rapidan Energy has estimated that the SPR has a “soft-ish floor” of roughly 170 million barrels, below which cavern integrity and pumping infrastructure limitations would increasingly argue against further withdrawals.
The disagreement illustrates an important distinction. There may not be a single number at which the Strategic Petroleum Reserve suddenly becomes unusable. Instead, its ability to operate efficiently could gradually deteriorate as inventories fall.
Less Oil Could Mean Slower Emergency Releases
One of the SPR’s biggest advantages isn’t simply the amount of crude it contains. It is the ability to move huge quantities of oil into the market quickly when a major supply emergency occurs.
That capability may decline as inventories fall. Misra said that once the reserve drops below 300 million barrels, its ability to pump oil at the rapid speeds needed during an emergency can become constrained.
As the oil layer near the top of a cavern becomes thinner, sludge can move closer to extraction equipment. Pipes and pumps may face greater risk of damage, while operators could have less flexibility to move crude through the system at maximum capacity.
Seventy million barrels may therefore represent a strict physical minimum needed to keep extraction pipes safely submerged in oil rather than water. But that doesn’t mean the United States could efficiently release those remaining barrels at the speed required during a major crisis.
For an emergency reserve, that distinction is critical. Hundreds of millions of barrels underground provide much less protection if infrastructure limitations prevent them from reaching the market quickly enough.
Aging Infrastructure Is Already a Problem
The reserve’s infrastructure challenges aren’t entirely theoretical. Energy Department officials told the GAO that they were holding portions of the SPR infrastructure together with “Band-Aids” and that it was uncertain how long those fixes would last.
As of December 2025, more than one-quarter of the SPR inventory was unavailable for drawdown because of construction and cavern outages, according to the GAO. Those limitations could become increasingly important if another major supply crisis emerges while the reserve is still recovering from the Iran-related release.
The SPR stood at roughly 415 million barrels before the Iran war. The planned 172-million-barrel release will ultimately reduce it to approximately 243 million barrels, a dramatic decline from the more than 700 million barrels the reserve held near its historical peak.
The United States is therefore approaching potential future emergencies with a much smaller strategic cushion than it possessed during much of the SPR’s history, while simultaneously dealing with infrastructure that has undergone decades of drawdowns and refilling cycles.
Concerns Have Crossed Party Lines
Warnings about the physical condition of the SPR aren’t confined to one political party. Republican lawmakers raised similar concerns when the Biden administration released a record 180 million barrels in 2022 following Russia’s invasion of Ukraine and the resulting surge in global energy prices.
The SPR subsequently fell below 350 million barrels in 2023 before inventories were rebuilt to approximately 415 million barrels ahead of the Iran war. The latest crisis has now reversed much of that rebuilding effort and pushed the reserve below 300 million barrels.
That cycle illustrates the increasingly difficult balancing act facing Washington. Releasing oil from the SPR can soften the economic damage from a severe global supply disruption, helping stabilize crude supplies and potentially limiting increases in gasoline and other energy prices.
But repeatedly drawing down and refilling the caverns can impose physical costs on infrastructure that wasn’t designed for unlimited cycles. Policymakers must therefore balance the immediate economic benefits of releasing crude against preserving the reserve’s ability to function during future emergencies.
Hurricane Season Adds Another Risk
The timing creates an additional concern as the United States moves through Gulf Coast hurricane season. Major hurricanes can disrupt offshore oil production, refineries, pipelines and ports across Texas and Louisiana, precisely the region where much of America’s energy infrastructure and the SPR itself are concentrated.
Hochstein warned that a major hurricane striking Florida or Louisiana while inventories remain depressed could put the United States in a difficult position. “Below 300 million, which is where we are now, it is not that we can’t do it, but it slows the flow and puts us in danger,” he said.
A severe hurricane occurring alongside continued disruptions from the Iran war could force Washington to confront two energy emergencies simultaneously. With the reserve already heading toward roughly 243 million barrels, the government’s ability to respond as aggressively as it has in previous crises could become increasingly constrained.
America’s Emergency Cushion Is Getting Thinner
The United States still has hundreds of millions of barrels of emergency crude underground, and the Department of Energy maintains that the reserve can continue operating safely. The immediate question isn’t whether the SPR suddenly stops functioning when inventories cross an arbitrary threshold.
The bigger concern is whether continued depletion gradually reduces the reserve’s ability to do the job it was created to perform. With inventories at their lowest level since 1983, aging infrastructure already limiting access to portions of the stockpile and experts disagreeing over how much further the reserve can safely be drawn down, the margin for error is shrinking.
The current release is intended to help America weather today’s energy disruption. But if inventories ultimately fall to approximately 243 million barrels, Washington could face a much harder question the next time war, a hurricane or another major supply shock hits:
How much emergency oil can the United States afford to use today without weakening its ability to respond tomorrow?
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