FACTBOX: The Strait of Hormuz, Iran and the risk

LONDON (Reuters) - Here are some facts about the Strait of Hormuz, the sea channel which flows along Iran's coastline at the entrance to the Gulf.

It is the world's most important waterway because of the huge volume of oil exported through it.

-- Oil flows through the Strait account for roughly 40 percent of all seaborne oil traded, according to the U.S. Energy Information Administration (EIA).

- The majority of oil exported from the Strait of Hormuz travels to Asia, the United States, and Western Europe. Some three-quarters of all Japan's oil needs pass through this Strait.

-- In July 2008, the International Energy Agency (IEA) estimated that more than 15 million barrels per day (bpd) of crude passed through the narrow channel on tankers.

-- An additional 2 million barrels of oil products, including fuel oil, are exported through the passage daily, as well as liquefied natural gas (LNG).

-- Exports from the world's largest LNG exporter Qatar also pass through the Strait en route to Asia and Europe, totaling some 31 million metric tons a year.

-- Ninety percent of oil exported from Gulf producers is carried on oil tankers through the Strait.

-- One of U.S. Central Command's (CENTCOM) key missions in the Gulf is to ensure the free flow of oil and energy supplies.

-- Between 1984 and 1987, a "Tanker War" took place between Iran and Iraq, where each nation fired on the other's oil tankers bound for their respective ports. Foreign-flagged vessels were caught in the crossfire.

-- Shipping in the Gulf dropped by 25 percent because of the exchange, forcing the intervention of the United States to secure the shipping lanes.

-- Iran has admitted to deploying anti-aircraft and anti-ship missiles on Abu Musa, an island strategically located near the Strait's shipping lanes.

-- The EIA predicts oil exports passing through the strait will double to between 30 million and 34 million bpd by 2020.

-- Merchant ships carrying grains, iron ore, sugar, perishables and containers full of finished goods also pass through the strategic sea corridor en route to Gulf countries and major ports like Dubai.

-- Heavy armor and military supplies for the U.S. armed forces in Iraq and other Gulf countries pass through the channel aboard U.S. Navy-owned, U.S.-flagged and foreign-flagged ships.

-- Geographic location: a narrow bend of water separating Oman and Iran connects biggest Gulf oil producers like Saudi Arabia with the Gulf of Oman and the Arabian Sea.

-- At its narrowest point, the Strait is only 34 miles (55 km) across.

-- The Strait consists of 2-mile (3.2-km) wide navigable channels for inbound and outbound tanker traffic as well as a 2-mile-wide buffer zone.

Sources: International Energy Agency (IEA), U.S. Energy Information Administration (EIA), United Nations Conference on Trade and Development (UNCTAD), GlobalSecurity.org, U.S. Navy's Military Sealift Command, Clarkson shipping consultancy.

(Reporting by Santosh Menon, editing by Anthony Barker)