Experts have raised concerns about potential damage to the U.S. strategic oil reserve caverns as inventories have fallen to a four-decade low. The Strategic Petroleum Reserve (SPR) has dropped below 300 million barrels for the first time since the early 1980s, according to data from the Department of Energy released on August 14, 2026. This decrease is attributed to the release of 172 million barrels in response to supply disruptions linked to the Iran war.
The Energy Department has indicated that at least 70 million barrels must remain in the reserve to manage the caverns safely. However, Amos Hochstein, a senior energy advisor to President Biden, disputed this figure, stating that depleting the reserve to 70 million barrels would compromise its integrity. He emphasized that going below 300 million barrels risks damaging the caverns that store the oil.
Ben Dietderich, a spokesman for the Energy Department, countered claims regarding the risk of cavern collapse, asserting that the caverns are always full, with only the ratio of oil to water changing. Concerns about the integrity of the caverns have been voiced by lawmakers from both political parties, especially following significant drawdowns in response to geopolitical events.
The Government Accountability Office (GAO) reported that repeated drawdowns could lead to structural issues within the caverns. While the majority of the SPR's caverns were found to be in good condition after the 2022 drawdown, the GAO noted that every drawdown cycle reduces the long-term viability of the caverns.
Experts suggest that the practical operational floor for crude inventory is between 250 million and 300 million barrels. At current levels, the integrity of the caverns and the operational capability of the SPR are at risk. If the inventory drops below 300 million barrels, the SPR may struggle to respond quickly to emergencies, and the infrastructure could be compromised.
Hochstein warned that a natural disaster could exacerbate the situation, stating that current levels slow response times and pose risks to energy security.