Contents

• Introduction
• Control of the Strait
• Inbound and Outbound Ships
• Food and Animal Feed
• Steel and Construction Materials
• Automobiles
• Oil and Gas Byproducts
• Jones Act Waiver
• National Security Fleets

Introduction

Before U.S. and Israeli military operations began against Iran on February 28, 2026, the average number of ships from various countries transiting through the Strait of Hormuz (the Strait) was about 130 each day.¹ As of April 7, 2026, only a handful of ships have risked the transit each day since the start of the operations for fear of attack by Iranian forces, which are reportedly negotiating with and permitting selected ships to pass through the Strait. Before the conflict began, the Strait was open to ship navigation without constraint as per long-standing international law,² but since the conflict began, Iran has asserted control over the Strait. The U.K. Maritime Trade Operations center has recorded 17 attacks on vessels since March 1, 2026, with several crew members killed or seriously injured.³ An estimated 1,000 ships are in a holding pattern in the Persian Gulf region: 800 ships in the Persian Gulf inside the Strait waiting to transit eastbound and 200 ships outside the Strait waiting to transit westbound.⁴ The announcement of a two-week ceasefire on April 7, 2026, to allow these ships to pass through the Strait without being fired upon does not appear to require Iran to give up its control over the Strait.⁵

While much attention has focused on the decrease in non-Iranian oil and gas shipments, some other commodities and products are affected, and U.S. shippers and ports may face cascading effects.⁶ Passage through the Strait may be constrained and entail risks even if active military exchanges end.⁷ The situation has also affected five U.S.-flagged ships in the Persian Gulf and U.S.-flagged ships sailing between domestic ports with the Trump Administration's issuance of a Jones Act waiver, which allows foreign-flagged ships to carry certain products between U.S. ports.

At issue for Congress is Iran's attempt at controlling the Strait, the commodities in addition to oil that cannot be shipped to or from Persian Gulf ports, and the safety of U.S.-flag ships that may be in the region. This report first briefly describes the status of the Strait as of the publication date of this report, then identifies non-oil products that are significant to seaborne trade between the Persian Gulf and the United States, and lastly discusses the Iran conflict's effect on U.S.-flag shipowners.

Control of the Strait

An issue for Congress is a potential change in the status of the Strait from its norm, long established by international law,⁸ as an open waterway free to navigation and unencumbered by any coastal state to one in which Iran seeks to maintain its present control over transit passage through the waterway. Reportedly Iran, but more specifically the Islamic Revolutionary Guard Corps, is charging tolls for ships to pass through, although it is disputed whether shipowners are actually paying the tolls.⁹ Iran has moved the shipping lanes much closer to its coastline under an unsubstantiated premise that harbor mines¹⁰ have been placed in the normal designated shipping lanes.¹¹ These developments may inform congressional consideration of legislative and oversight options regarding the effects of the Iran conflict on U.S. shippers and non-oil shipments in the area.

Inbound and Outbound Ships

Jebel Ali in the United Arab Emirates (UAE) is the leading container port hub in the region, and the world's ninth largest port in terms of number of containers handled.¹² About 65% of the port's container volume is transshipped onto feeder vessels for other ports in the Persian Gulf. Re-routing by truck is severely constrained and expensive, and air freight is economical only for products with exceptionally high value-to-weight ratios, which generally do not include foods.¹³ Ocean containers carry the same wide variety of goods that trucks typically carry. In addition to food, they carry clothing and household goods as well as equipment and parts for manufacturing facilities. Thus, the blockage of the Strait has wide-ranging effects for the economies in the region, beyond those from not being able to export petroleum.

Food and Animal Feed

Persian Gulf nations are dependent on ships for bringing in much of their food and other necessities. This includes dry bulk ships carrying corn, rice, soybeans, and wheat in unpackaged, bulk form for processing at grain mills. According to one report shortly after the start of the conflict, there were 280 dry bulk ships held up inside the Strait.¹⁴ Brazil and Argentina are leading sources for some of these commodities but so too is the United States. For instance, the United States is the top supplier of soybeans to the region.¹⁵ New Orleans, Portland, San Francisco, Houston, and Norfolk are the leading U.S. ports exporting these products to the region.¹⁶ Other items carried in dry bulk ships include sugar from Brazil and salt from India. Recognizing the potential vulnerability of the Strait, some Persian Gulf nations have built large storage facilities at their ports to store food commodities in bulk.¹⁷

Persian Gulf nations are also highly dependent on container ships to bring in packaged food, such as frozen chicken, for which South America and the United States, through the Port of Savannah, are leading suppliers.¹⁸ Persian Gulf nations are the destination for roughly 10% of the frozen chicken exported through the Port of Savannah. Fruits and nuts, fresh and chilled vegetables, and dairy products are other food categories relying heavily on container ships for delivery. The United States is a top supplier of these products from the ports of San Francisco (Oakland) and Seattle.¹⁹ Nearly all the corn oil exported from the ports of New Orleans and Savannah is destined for either Kuwait, Saudi Arabia, or Qatar.²⁰ Persian Gulf countries account for nearly 20% of U.S. exports by ship of condiments and sauces, such as ketchup and mustard.²¹ The top U.S. ports loading these products to the region are New York, Savannah, Norfolk, and New Orleans. Also shipped in containers are forage products (hay, clover, vetches) for animal feed, for which the United States (via the Port of Los Angeles) is the top supplier.²²

Steel and Construction Materials

Aluminum and steel manufacturing are two industries that may be significantly affected by the blockage of the Strait. Persian Gulf aluminum plants rely on ship delivery of alumina (the raw material for manufacturing aluminum) from Guinea, India, and Australia, among other sources. The Persian Gulf produces about 8% of the world's aluminum, including about 40% of the United States' waterborne aluminum imports.²³ The region accounts for almost all of the aluminum the ports of New York and Houston import by ship and nearly half of the aluminum received at the Port of Baltimore. The region's steel products represent a small share of total U.S. steel imports. Nevertheless, the supply of flat-rolled steel and steel beams, which are the primary steel articles that the United States imports from the region, may be affected by the blockage of the Strait.²⁴

The UAE and Saudi Arabia export large amounts of cement. These two countries account for about 16% of the total amount of cement imported at the ports of Houston and Savannah.²⁵ The Persian Gulf also exports large amounts of gypsum and limestone, which are also often used in construction projects, but is not a significant supplier to the United States.

Automobiles

Car carriers are another type of ship normally transiting the Strait to make deliveries in the Persian Gulf region. The UAE, in particular, is a major importer of passenger cars and appears to be the region's import distribution hub. The leading U.S. ports exporting cars to the region are New York, Savannah, and Houston.²⁶ In 2025, measured by weight of vehicles, the Persian Gulf countries accounted for over 20% of the United States' waterborne exports of passenger cars and 15% of trucks.²⁷

Oil and Gas Byproducts

In addition to oil and gas, byproducts of their production are also critical to the rest of the world. Qatar accounts for about 30% of the world's helium production capacity, most of which is a byproduct of its natural gas processing.²⁸ Among other uses, helium is used in semiconductor manufacturing, magnetic resonance imaging machines, and a range of research applications. It is shipped in large quantities by container ships in specially designed insulated and pressurized containers that keep the helium in liquid form at minus 452 degrees Fahrenheit for up to 45 days. Other byproducts of the oil and gas refining process are ethylene, methanol, and naphtha—the building blocks of plastics. Charleston, SC, in particular is reliant on paraxylene, a chemical used to manufacture plastic containers. About half of its waterborne imports are from Saudi Arabia.²⁹

The Strait carries about one-third of the world's seaborne trade in fertilizer inputs.³⁰ Many of these commodities are related to the region's oil and gas development. Natural gas is the building block for producing nitrogen fertilizer in the form of ammonia. Thus, the Persian Gulf is one of the world's major sources for this kind of fertilizer. Ammonia is shipped in liquid form in liquefied petroleum gas tankers, but ammonia is also used to produce urea, a solid, granular form of fertilizer shipped in dry bulk ships. The Persian Gulf countries account for nearly 40% of U.S. waterborne imports of Urea, which is mostly handled at the ports of New Orleans, LA; Portland, OR; Houston, TX; and Wilmington, NC.³¹

The oil refining process produces sulfur as a byproduct. Sulfur is used as both a fertilizer and to produce sulfuric acid that Africa, in particular, relies upon to leach out critical minerals in its mining operations. Saudi Arabia is an important source of phosphate fertilizer.

Jones Act Waiver

On March 17, 2026, the Trump Administration waived the Jones Act for 60 days—through May 17, 2026—in an attempt to facilitate transportation of commodities normally exported through the Strait, such as petroleum and fertilizers, and possibly dampen the price effects on those products in the United States.³² The Jones Act (Section 27 of the Merchant Marine Act of 1920, P.L. 66-261) restricts vessels transporting cargo between U.S. ports to those that are U.S.-built, owned, and crewed. This restriction significantly affects the availability and price of domestic coastal shipping. Under the waiver, the much larger fleet of foreign-built and flagged vessels is available to carry products listed in the waiver between U.S. ports.

National Security Fleets

The U.S. Maritime Administration (MARAD), part of the U.S. Department of Transportation, administers several programs to establish and sustain a fleet of active ships that are privately owned, commercially viable, and militarily useful to meet national defense and other emergency sealift requirements. Carriers receive fixed annual retainer payments in return for agreeing to register ships under the U.S. flag and to make them available upon request by the Secretary of Defense³³ during times of war or national emergency.³⁴ Under the Maritime Security Program (MSP), first established in the Maritime Security Act of 1996, up to 60 cargo ships engaged in foreign commerce are eligible to receive annual stipends from MARAD.³⁵ Under the similar Tanker Security Program (TSP) established by the FY2021 National Defense Authorization Act, up to 20 U.S.-flagged tankers engaged in foreign commerce are eligible to participate, though Congress has not provided funding for more than 10 vessels in any given year.³⁶

As of January 5, 2026, 60 vessels were enrolled in the MSP, and 9 were enrolled in the TSP.³⁷ Five of these vessels—vehicle carrier Alliance Fairfax, container ships APL Eagle and Maersk Yorktown in the MSP fleet, and tankers CS Anthem and Stena Imperative in the TSP fleet—were located in the Persian Gulf in February 2026 and had not departed as of April 1.³⁸ A prolonged closure of the Strait to commercial traffic could reduce the effectiveness of the MSP and TSP if participating vessels are prevented from assisting the Department of Defense.³⁹ The TSP is not at full enrollment, which could indicate that finding vessels to replace the two unable to leave the Persian Gulf may prove difficult. One such vessel, the CS Anthem, recently joined the TSP to replace another tanker that was damaged in a collision with a container ship in 2025.⁴⁰

Footnotes