UPDATE 1-BP evacuates Texas refinery workers after threats

(Recasts, adds information from FBI)

HOUSTON, Feb 15 (Reuters) - BP Plc. (BP.L) evacuated workers from parts of its giant Texas refinery on Wednesday and Thursday after bomb threats were made, the company said on Thursday .

The bomb threats were written in notes left in portable toilets or on the walls of the portable toilets at the refinery, said FBI Special Agent Shauna Dunlap.

Production at the Texas City, Texas, refinery was not affected, but repair and maintenance work was halted temporarily in those areas, said BP's Neil Chapman.

"It affected work on the plant," Chapman said. "It disrupted the work."

The Texas City refinery has a rated crude processing capacity of 460,000 barrels per day, making it the third largest refinery in the United States. But it has been operating at no more than half that level while repairs are being made to equipment damaged in the shutdown of the plant as Hurricane Rita menaced Texas City in September 2005.

BP is offering a $10,000 reward for information leading to the arrest of those making the threats, Chapman said.

Chapman declined to discuss what security precautions were being taken at the refinery since the threats were made.

Dunlap said searches were made of areas at the refinery where the threats were found, but no suspicious packages were discovered.

The Texas City refinery was the site of a deadly March 23, 2005 blast that killed 15 workers and injured more than 170 other people.