Strait of Hormuz

Assessing the threat to oil flows through the Strait

About the Strait

Over 90 percent of oil exports from the Persian Gulf pass through the Strait of Hormuz, a vital sea passage only 30 miles wide at its narrowest point. It is commonly believed that a tanker accident, a terrorist attack, or a military effort to close the Strait would send energy prices skyrocketing, threaten ing the global economy. Some scenarios might temporarily interrupt oil flows, while others, such as a major Iranian military attack, might have longer-term consequences.

This website is intended to help assess the threat to oil flows through the Strait. It provides background on the political, economic, business, technical, and military issues involved in potential disruptions. Oil producers, tanker and insurance companies, and regional and global military forces would all react to any attack on Persian Gulf shipping.

Historical and technical perspectives offered here should help readers attain careful, reasoned, responsible views of the severity of the dangers imposed by the world's dependence on the Strait of Hormuz.

Commercial Issues

Several different industries work together to satisfy global demand for oil, ranging from companies that explore and drill for oil to retailers that sell gas to motorists. Each would react in its own way to a disruption in the Strait of Hormuz. When business conditions change, firms don't surrender. They adapt.

Companies that pump oil out of the ground around the world (producers), transport oil in ships from producers to consumers (tanker owners), and indemnify the oil trade against in-transit losses (maritime insurers) would face the most immediate need to adapt to attacks on shipping in the Strait of Hormuz. To understand how a disruption would affect the global economy " and how big a disruption would need to be to threaten global prosperity " we need to understand how the market works in each of these industries.


Tankers carry over 40 million barrels of crude oil per day worldwide, or about two thirds of the world's oil trade.[i] Tankers are a flexible, cost-effective means of transporting oil to areas of highest demand. The largest of these vessels are over 1,000 feet long and can carry well over 2 million barrels of oil. Because of their enormous scale and the fact that so many travel through the narrow chokepoint of the Strait each day, these supertankers would certainly make attractive targets in any attempt to materially reduce the flow of oil to the global market.