The crisis caused by the closure of the Strait of Hormuz is no longer affecting only oil prices. Record diesel prices, the widening refined-products-to-crude spread to around $100 a barrel, and the decline in US strategic reserves to below 300 million barrels show that the cost of the energy war has moved beyond the global oil market and reached Washington’s energy security balance.

To understand the true scale of the energy crisis caused by the Strait of Hormuz, it is not enough to look only at the crude oil price chart. Perhaps the most important sign of the pressure can be seen in the market where crude oil is turned into a usable product: the refined-products market.

In recent days, diesel and other refined petroleum products have seen a significant price surge, while the spread between refined products and crude oil has widened to around $100 a barrel. This development is economically significant because when refined products become more expensive faster than crude oil, the market is effectively signaling that the problem is not simply a shortage of oil. The problem has emerged across a chain connecting oil to refineries, refineries to refined products, and refined products to the end consumer.

Diesel is an important indicator in this regard. It is vital to road transportation, agriculture, industry and the supply chain for goods. A sharp increase in its price is therefore not merely an event in the energy market; it can increase the cost of transporting, producing and distributing goods and ultimately add to inflationary pressures.

This is where the significance of the diesel-to-crude spread becomes clear. If crude oil is the barrel priced at the source, diesel is a product that absorbs additional costs, from refining and refinery capacity to transportation, insurance, route risks and disruptions to regional supply.

Therefore, the wider this spread becomes, the clearer it is that a greater share of the cost of the crisis has been transferred to the lower levels of the energy supply chain.

At the center of this chain is the Strait of Hormuz.

Hormuz is not merely a route for crude oil. The strait is part of the vital artery of global energy trade, and any disruption affects not only oil supplies but also shipping routes, insurance costs, transit times, refineries’ access to feedstock, and the flow of refined petroleum products.

That is why a barrel of oil may still be available in the global market, while the cost of turning it into usable fuel and delivering it to its destination can rise sharply.

This is the point at which the crisis moves from the oil market into energy security.

The second sign of this shift, however, is the condition of America’s strategic reserves.

US Strategic Petroleum Reserve inventories have now fallen to about 298.7 million barrels, dropping below the 300-million-barrel threshold for the first time since the early 1980s. More than 6 million barrels were also drawn from the reserve in the latest reported week.

The SPR was essentially created for days like these: when global oil supplies face serious disruption and the US government needs to release oil to offset part of the market shock.

But this same tool can become a weakness if the crisis persists.

Every barrel released from the strategic reserve today reduces part of America’s capacity to respond to the next crisis. Washington therefore faces a difficult dilemma: if it uses the reserves, its future safety margin declines; if it does not, pressure from refined-product prices and energy inflation increases today.

This becomes even more important when we consider that pressure in the refined-products market is precisely where an energy shock is transmitted to the real economy.

Record diesel prices, the refined-products-to-crude spread, and the decline in the SPR are not three independent data points; they are three links in the same chain.

The first link is higher energy costs for consumers.

The second is the increased cost of disruption to the supply and refining chain.

The third is the consumption of part of the reserve that was intended to serve as an emergency backstop for the US economy.

From this perspective, the figure of 298.7 million barrels should not be interpreted as meaning that “America is running out of oil”. The US remains a major oil producer, and its commercial oil inventories are separate from the SPR. The main issue is the reduction in its strategic room for manoeuvre.

The US may have oil, but energy security does not depend solely on the number of barrels available. Energy security means the ability to deliver energy at an affordable price, at the right time and through routes that are not vulnerable to geopolitical shocks.

The Hormuz crisis is putting precisely this definition under pressure.

If the disruption is short-lived, Washington can absorb part of the pressure through the use of reserves, changes in trade routes, increased imports and higher domestic production. But if the crisis continues, every day of SPR withdrawals consumes part of its capacity to respond to the future, while higher refined-product prices simultaneously transfer the cost of the crisis to the US economy.

For this reason, the real significance of the decline in strategic reserves below 300 million barrels must be understood alongside record diesel prices and the widening refined-products-to-crude spread.

Hormuz first put pressure on oil prices; it then transferred that pressure to refined products, and now part of the cost is appearing in America’s energy security balance.

This may be one of the most important shifts in the energy-war equation.

As long as the crisis was visible only in the crude oil market, Washington could largely treat it as a pricing issue. But when diesel prices hit records, the refined-products-to-crude spread widens and the strategic reserve simultaneously falls to its lowest level in decades, the issue is no longer simply price. The issue is resilience.

Under these circumstances, the strategic question begins here: if the Hormuz crisis continues, how long can the US afford to draw down tomorrow’s energy security reserves to manage today’s costs?

In this equation, perhaps the most important impact of Hormuz is not the number of barrels removed from the market, but the reduction in the safety margin of countries forced to consume their strategic reserves to cope with an energy shock.

In this sense, the cost of Hormuz is no longer written only on the oil price board; part of it is now being recorded on America’s energy security balance sheet.