FACTBOX - Gustav cuts U.S. oil and gas and threatens commods

(Reuters) - Gustav is first big threat to U.S. Gulf of Mexico energy and port infrastructure since Katrina and Rita in 2005.

The Gulf is the source of 25 percent of domestic oil and 15 percent of the natural gas. More than a third of U.S. refining capacity is on the U.S. Gulf Coast.

Near expected landfall is New Orleans, a big port handling raw material and foodstuff. The Port of South Louisiana is the largest U.S. port in tonnes handled.

On the western edge of the possible target zone is Houston, a major port, oil refining and crude oil and natural gas hub.

Katrina and Rita were Category 5 storms, the top of the hurricane intensity scale. Katrina hit New Orleans in August 2005. Rita hit near the Texas-Louisiana line that September.

Gustav was expected to come ashore as early as Monday on the Gulf Coast as at least a Category 3, though it was weaker Sunday than when it crossed Cuba Saturday.

---- GENERAL IMPACTS ----

- The U.S. Minerals Management Service said Sunday 1.25 million of 1.3 million barrels per day (bpd) of oil production (96.3 percent) and 6.1 billion of 7.4 billion cubic feet per day of gas (Bcfd) production (82.3) had been shut in anticipation of Gustav. Up from 76.8 percent of oil and 37.2 percent of gas Saturday.

- MMS said personnel evacuated from 518 of 717 manned production platforms (72.3 percent), up from 223, and 86 of 121 drilling rigs (71.1 percent) in the Gulf, up from 45.

- NYMEX crude oil surged more than $2 a barrel to more than $117 a barrel in early electronic trading Sunday. Products also rose.

---- FUEL RELIEF ----

- The U.S. Environmental Protection Agency waived summer blend requirements in Louisiana to ease gasoline supply as refineries shut down.

---- OIL IMPORTS THREATENED ----

- Louisiana Offshore Oil Port stopped unloading ships Saturday and shut flows from storage Sunday.

- Oil from the Strategic Petroleum Reserve will be tapped, if necessary, the U.S. Department of Energy said.

---- SPECIFIC CUTS OFFSHORE OIL, GAS OUTPUT ----