GULF COAST — The reserve is stored in 60 underground salt caverns located at four sites in Texas and Louisiana. The total storage capacity of these caverns is 714 million barrels. Operators must pump fresh water into the facilities to keep the total fluid volume at that level and maintain pressure stability during drawdowns.

Pumping cool water into the naturally higher-temperature caverns can cause thermal shock, leading to salt pieces falling and potentially damaging extraction pipes. The caverns were constructed in the 1970s and 1980s with an initial design life of 25 years and engineered to handle five drawdowns and refills. The reserve has undergone dozens of releases since its construction.

Siddharth Misra, associate professor of petroleum engineering and geophysics at Texas A&M University, stated that repeated injection of water and extraction of oil have caused severe cavern deformation, accelerated the rate of massive salt falls from the ceilings, and weakened the overall structural integrity of the aging reserve.

He said that from an engineering and geomechanical standpoint, these concerns are highly valid. Salt is a highly dynamic rock type, and aggressively altering the fluids, pressure, and temperatures inside these deep caverns directly threatens their structural integrity.

Misra stated that repeated rapid drawdowns wash away salt walls, creating flatter, less stable roofs and severely thinning the critical salt pillars that separate adjacent caverns, which increases the geological risk of a structural cave-in. He also noted an increased risk of physical damage from an oil-water-impurity sludge layer rising near the ceiling intake of the extraction system, which can destroy surface pumps.

He said the reserve should be highly concerned about the integrity of the caverns anytime crude inventories drop below 300 million barrels. At these depleted levels, the reserve physically loses its ability to pump oil at the rapid emergency speeds it was built to achieve without risking severe structural damage. Misra noted that while 70 million barrels is the absolute threshold needed to keep intake pipes under oil rather than water, the practical operational floor for the crude inventory is between 250 million and 300 million barrels.

Amos Hochstein, senior energy advisor for former President Joe Biden, expressed similar concerns about the physical limits of the infrastructure. He said he doesn’t know anyone who believes the U.S. can go below 300 million barrels. Hochstein added that many believe the reserve cannot get near 300 million because physically, the caverns would be damaged.

A Government Accountability Office report released in June stated that most Strategic Petroleum Reserve caverns were in "very good condition" as of May. However, the agency warned that "every drawdown cycle expands cavern volume and reduces the spacing between caverns within the salt dome, which ultimately reduces their long-term viability." The Government Accountability Office reported that repeated partial drawdowns followed by refill can leach a single part of a cavern repeatedly, leading to undesirable shapes.

Timeline

The Strategic Petroleum Reserve fell below 350 million barrels in 2023. In January 2025, Energy Secretary Chris Wright testified that more than $100 million in repairs were needed for Strategic Petroleum Reserve facilities. Wright stated, "The immediate thing we need to do is finish the repairs on the Strategic Petroleum Reserve. It was drawn down so quickly, and that causes some damage to the infrastructure itself. Those repairs are ongoing, and it costs a nontrivial amount of money to repair the SPR."

What's New

Additional reporting indicates that Amos Hochstein said depleting the reserve to 70 million barrels would reach the point of never resurrecting it." He also said people should not believe government claims that the SPR can go to 70 million barrels, calling such statements nonsense. Records show the Strategic Petroleum Reserve fell below 350 million barrels in 2023."

Further details reveal that the Government Accountability Office found more than a quarter of the Strategic Petroleum Reserve inventory was not available for drawdown due to construction and cavern outages as of December 2025. Rapidan Energy analysts estimated the Strategic Petroleum Reserve has a "soft-ish floor" of around 170 million barrels, below which cavern integrity and pumping infrastructure limitations argue against further draws. The Strategic Petroleum Reserve was refilled to around 415 million barrels before the Iran war.

Siddharth he noted that while 70 million barrels is the absolute threshold needed to keep intake pipes under oil rather than water, the practical operational floor for the crude inventory is between 250 million and 300 million barrels. Energy Department officials told the Government Accountability Office that they are holding the Strategic Petroleum Reserve infrastructure together with temporary measures and are uncertain how long they will hold.

How Sources Differ

There is disagreement regarding strategic petroleum reserve barrels. Siddharth he stated that the Strategic Petroleum Reserve will hit its legal limit of 252 million barrels in about three months if extraction continues at a pace of 500,000 barrels per day. Department of Energy data shows the Strategic Petroleum Reserve fell below 300 million barrels for the first time since the 1980s.

The Department of Energy projection expects the reserve to decrease to 243 million barrels after the current release of 172 million barrels is completed. Department of Energy facility records state the total storage capacity of the Strategic Petroleum Reserve caverns is 714 million barrels. Department of Energy inventory records show the Strategic Petroleum Reserve fell below 350 million barrels in 2023. Rapidan Energy analysis estimates the Strategic Petroleum Reserve has a "soft-ish floor" of around 170 million barrels, below which cavern integrity and pumping infrastructure limitations argue against further draws. The Department of Energy announcement states the United States is releasing 172 million barrels from the Strategic Petroleum Reserve to manage supply disruptions and rising energy costs due to the Iran war.

Sources also differ on the stated strategic petroleum reserve status. Siddharth he stated that the Strategic Petroleum Reserve will hit its legal limit of 252 million barrels in about three months if extraction continues at a pace of 500,000 barrels per day. A Government Accountability Office report released in June stated that most Strategic Petroleum Reserve caverns were in "very good condition" as of May.

Why It Matters

The Strategic Petroleum Reserve serves as a critical national security asset designed to stabilize oil markets and protect against supply disruptions. With inventories falling below 300 million barrels for the first time since the 1980s, the physical integrity of the 60 underground salt caverns in Texas and Louisiana faces unprecedented stress. The reserve was engineered for only five drawdown and refill cycles, yet it has undergone dozens, raising questions about its long-term viability.

Independent oversight bodies and engineering experts warn that the infrastructure is being held together by temporary measures. The Government Accountability Office noted that every drawdown cycle reduces the spacing between caverns, while Energy Department officials admitted uncertainty about how long current repairs will hold. As the United States proceeds with a 172 million barrel release to address energy costs related to the Iran war, the gap between the Department of Energy's 70 million barrel operational minimum and expert warnings of structural damage below 300 million barrels shows a conflict in assessing the reserve's true operational floor.

Ben Dietderich stated, "The caverns are always full. All that"