(Adds no comment from Petrobras)
SAO PAULO, Aug 22 (Reuters) - Brazil's state-run oil company Petróleo Brasileiro SA may begin procedures to reopen its largest refinery, closed after an explosion and fire, in 48 hours, Gustavo Marsaioli, a spokesman for the oil workers' union, said on Wednesday.
Marsaioli said Petrobras intends to reopen the Paulinia refinery, known as Replan, at half-capacity given the fire early on Monday that affected part of the facility. The unaffected part may go back into production a week after procedures for reopening are completed, Marsaioli said.
Petrobras did not immediately respond to a request for comment.
Replan accounts for about 20 percent of Petrobras' refining capacity, processing the equivalent of 434,000 barrels of oil per day, according to the company's website.
A Petrobras executive said the incident was serious but that the company had enough stocks to cover Replan halting operations for 15 days. (Reporting by Roberto Samora; Writing by Tatiana Bautzer and Alexandra Alper; editing by Jonathan Oatis and Susan Thomas)