HOUSTON, Sept 9 (Reuters) - Chevron ( CVX ) on Monday

began evacuating all staff and shutting in oil and gas output at

two U.S. Gulf of Mexico offshore production platforms, a

spokesperson said.

The production halt affected its Anchor and Tahiti

platforms. Operations continue as normal at its other offshore

platforms and at onshore facilities, the spokesperson said.

Earlier, Chevron ( CVX ) said it was evacuating non-essential staff

at its Big Foot and Jack/St. Malo platforms ahead of Tropical

Storm Francine. The storm is expected to become a category 1

hurricane with winds of at least 74 miles per hour (119 kph) as

soon as Tuesday.