According to a classified briefing to Congress, fully clearing Iranian mines from the Strait of Hormuz could take half a year — and the operation probably can’t even begin until the shooting stops. Here’s what that means for oil, the global economy, and anyone who pays a gas bill.

The Strait of Hormuz is 21 miles wide at its narrowest point. Through that 21-mile gap flows roughly one-fifth of the world’s seaborne oil supply — every single day, in peacetime. Right now it is not peacetime, and the Pentagon has quietly told Congress something that should probably be front-page news everywhere: even after a ceasefire, it could take up to six months to make that passage safe again.

The Washington Post first reported the assessment, citing officials familiar with a classified briefing given to House Armed Services Committee members. Pentagon spokesman Sean Parnell pushed back hard, calling the report based on “cherry-picked” information from a closed session and insisting the characterization was “false.” But he didn’t say six months was wrong. He said the framing was unfair. That’s a meaningful distinction — and a careful one.

“Asix-month closure of the Strait of Hormuz is an impossibility and completely unacceptable to the Secretary.”— PENTAGON SPOKESMAN SEAN PARNELL

The core problem is physical, not diplomatic. Iran’s Revolutionary Guards have warned shipping of a “danger zone” stretching across roughly 1,400 square kilometers — an area fourteen times the size of Paris — where mines may be present. And here’s the part that makes military planners lose sleep: according to one report, Iran itself has lost track of some of the mines it planted. That’s not spin. That’s a Navy nightmare. You can negotiate a ceasefire. You cannot negotiate with an untracked sea mine sitting 40 feet below the surface of a major shipping lane.

Mine clearance is slow, painstaking, dangerous work. It involves specialized vessels, underwater drones, sonar sweeps, and — when all else fails — controlled detonations. The US Navy began mine clearance operations in the strait in early April, but that effort was immediately disputed by Iran’s Revolutionary Guard, which threatened any military vessels attempting to enter. The operation has been contested from the start, and the Pentagon’s assessment apparently reflects what a realistic, uncontested clearance would actually require — not an optimistic scenario, but an honest one.

HOW WE GOT HERE — KEY TIMELINE

Mar 10US intelligence confirms Iran begins planting naval mines in the strait. First ship attacks reported.

Mar 19US military launches campaign to reopen the strait. Brent crude surges past $120/barrel.

Apr 8Temporary ceasefire agreed, including a promise to reopen the strait. Iran begins charging $1M+ tolls per ship instead.

Apr 13Trump announces full US naval blockade of Iranian ports after ceasefire talks collapse.

Apr 17Iran declares strait open to commercial traffic — but the US blockade remains and few ships transit.

Apr 22Pentagon briefs Congress: full mine clearance could take six months after hostilities end.

Apr 2330+ nations convene in London to plan multinational mine-clearance and navigation protection mission.

The economic consequences of all this are already staggering — and the six-month timeline makes them worse. The Federal Reserve Bank of Dallas estimated that the Hormuz closure is on track to push WTI oil prices to around $98 per barrel and shave nearly three percentage points off annualized global GDP growth in the second quarter alone. Bloomberg has reported that Wall Street analysts are quietly modeling $170 — and in a worst-case scenario, $200 — per barrel. The IEA has called this “the largest supply disruption in the history of the global oil market.” That phrase doesn’t get used lightly.

The ripple effects reach well beyond oil. Around 20% of the world’s liquefied natural gas passes through Hormuz — and unlike oil, there’s no pipeline workaround, no strategic reserve, no alternative route to reroute LNG at scale. Qatar, the world’s largest LNG exporter, declared force majeure on all exports when the closure began. European gas benchmarks have nearly doubled. Chemical manufacturers — who need petroleum as a feedstock for plastics, resins, and synthetic fibers — are passing surcharges of up to 30% down their supply chains. The electric vehicle industry is watching synthetic graphite prices closely; the petroleum coke it’s made from is suddenly a lot harder to come by.

“The world still hasn’t grasped the severity of the situation.”— OIL AND GAS TRADERS, BROKERS, AND EXECUTIVES, AS REPORTED BY BLOOMBERG

On the diplomatic front, there’s movement — but it’s slow. Talks between the US and Iran have seesawed between apparent progress and collapse for weeks. Iran’s parliament speaker has said flatly that the strait will not reopen as long as the US naval blockade of Iranian ports remains in place. The US maintains the blockade is a response to Iran charging illegal transit tolls and continuing to threaten shipping. Neither side is obviously wrong about their own position, and neither side appears close to giving the other what it needs to step back.

Meanwhile, in London on Wednesday, military planners from more than 30 nations began two days of talks on a UK and France-led multinational mission to protect navigation and conduct mine clearance once — or if — hostilities end. The operative word in that sentence is “once.” The coalition is planning for the aftermath of a war that isn’t over yet, and the six-month mine-clearance estimate is a reminder of exactly how long the aftermath could last even in a best-case scenario.

Marine veteran Alex Martin, speaking on Fox News Wednesday morning, framed the practical challenge clearly: you can escort a handful of commercial ships through the strait with destroyers providing air cover, but doing it sustainably for months requires resources — and willingness — that the current standoff makes difficult to guarantee. The strait may be technically “open” on paper. Open enough to reliably move 20 million barrels of oil a day through it is a different question entirely.

Six months is not a verdict. It’s an assessment, and the Pentagon says parts of it were misrepresented. But even if the actual timeline turns out to be three months, or four, the underlying point stands: the world’s most important oil chokepoint has been mined, the war isn’t over, and the clearance operation can’t start in earnest until it is. The global economy is running the clock on that — one barrel at a time.

 Iryna Olar