RIO DE JANEIRO, Jan 7 (Reuters) - Brazil's state-run oil company Petroleo Brasileiro SA sharply cut output from its 208,000-barrel-a-day REPAR refinery after a malfunction forced a two-week shutdown at its catalytic-cracking unit, union officials said on Wednesday.
The U-2200 cracking unit at REPAR, in Araucaria in Brazil's southern Parana state, was halted on Dec. 21 and restarted on Jan. 3, the union said.
The shutdown likely cut processing by as much as half and gasoline output by about a third, an industry source said, requesting anonymity because they were not authorized to speak to the press.
The unscheduled shutdown is the second serious operating problem to hit REPAR in a year. A fire at REPAR's atmospheric distillation unit closed the plant for nearly a month in late 2013.
The latest problem at REPAR, which provides about 10 percent of Brazil's fuel output, seriously threatened gasoline supplies to the northern part of the neighboring state of Santa Catarina, an industry official with direct knowledge of the country's fuel distribution system told Reuters.
REPAR is also known as the Getulio Vargas Refinery.
Union officials at REPAR said Petrobras refused to tell them the extent of the unit shutdown on crude processing capacity or fuel production.
Petrobras officials were not immediately available for comment.
The unit broke after a part came loose and fell into the boiler unit, the union said. After about 150 workers were detailed to the unit for repairs, U-2200 was restarted on Jan. 3, the union said. (Editing by Alan Crosby)