(Corrects headline to indicate source was a local official, not Marathon)
May 28 (Reuters) - Marathon Petroleum's refinery in Garyville, Louisiana, was partially shut on Wednesday by power outages from a storm that knocked out electricity for more than 1,000 residents, according to a local official.
Marathon is still assessing damage at the refinery, according to Brandon Daniels, a Findlay, Ohio-based spokesman for the company. The plant has the ability to process about 490,000 barrels a day.
The area was issued a tornado warning at 5:30 a.m. CDT (1030 GMT) and experienced heavy winds, said Paige Falgoust, communications director at the St. James Parish Emergency Preparedness Office.
"Marathon Petroleum had a weather event, and they're assessing the damages at this time. There was wind damage during the time of the tornado warning," Falgoust said, adding that Marathon hadn't confirmed which units were impacted.
"They did have a power outage" and there was some flaring at the plant, she said.
If key units at the plant are shut, Marathon would consume less Light Louisiana Sweet crude, which could weaken the price of the grade, according to a broker in the market. (Reporting By Jessica Resnick-Ault; Editing by Meredith Mazzilli and Paul Simao)