The reserve declined by 6.1 million barrels to 298.7 million barrels last week, according to data from the Department of Energy cited in the report. That would put the SPR at its lowest level since January 1983.
The sharp decline comes after the Trump administration ordered a massive release of oil in March following disruptions to crude exports through the Strait of Hormuz. The administration authorised the release of 172 million barrels in an effort to ease pressure on global oil supplies.
The scale of the drawdown has renewed debate over how much oil the United States can realistically deploy in another major energy emergency.
Questions grow over the SPR's remaining capacity
Despite the steep decline in stocks, energy experts say the reserve is not yet close to being completely depleted.
The minimum level of crude needed to safely operate the SPR is about 70 million barrels, according to an Energy Department spokesperson cited by CNBC in July.
David Goldwyn, who previously served as a State Department special envoy for international energy affairs under President Barack Obama, said the remaining stockpile would still provide the government with room to respond to another supply disruption.
“I’m not worried about the stability of the reserve or our ability to do another drawdown if we needed to,” Goldwyn told CNBC.
Before the U.S. and Israel attacked Iran on February 28, the SPR held roughly 415 million barrels. Once the full release ordered by Trump is completed, U.S. government stocks are expected to fall to around 243 million barrels.
The reserve has an authorised storage capacity of approximately 714 million barrels, meaning its current holdings are significantly below the level it was designed to accommodate.
Ageing infrastructure adds to the concern
The amount of oil stored in the SPR is only part of the issue. The government's ability to rapidly extract and distribute that oil is also facing challenges.
A May report by the Government Accountability Office warned that ageing infrastructure is putting the reserve's operational capability at risk.
According to the report, more than a quarter of the reserve's oil was “not available for drawdown due to a combination of construction outages and cavern outages” as of December 2025.
Rapidan Energy's July analysis estimated that at least 103 million barrels currently held in the SPR may therefore not be immediately deployable.
The GAO also warned that the reserve's ability to draw down, distribute and replenish crude is being constrained by longstanding infrastructure problems.
“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 said.
The concern is particularly significant because the SPR is intended to serve as an emergency buffer during major disruptions to the global oil market. Having large quantities of crude underground is of limited value if portions of the reserve cannot be accessed quickly when needed.
Repeated releases put pressure on the reserve
The United States has increasingly relied on the SPR during periods of severe energy market disruption.
In 2022, President Joe Biden ordered the release of 180 million barrels following Russia's invasion of Ukraine and the resulting volatility in global energy markets. It remains the largest single release in the reserve's history.
The GAO described that release as an “unplanned stress test” for the SPR.
Repeated withdrawals can also increase the strain on ageing infrastructure, particularly the wells and equipment used to move crude out of underground storage caverns.
“When you do a drawdown, then you accelerate kind of the degradation of the wells themselves and some of the equipment,” Goldwyn said. “It’s like anything else — you use it a lot, you have to maintain it.”
The latest decline therefore raises two separate questions for Washington: how much crude should remain in the emergency reserve, and how quickly can the government actually access what is left?
With the SPR already well below its authorised capacity and infrastructure upgrades still under way, rebuilding the stockpile could become an important energy-security priority once the current crisis eases.