UPDATE 1-Small explosion hits Venezuela's Amuay oil refinery
(Adds union comment, PDVSA confirmation, flexicoker details, background)
PARAGUANA, Venezuela, July 3 (Reuters) - A small explosion and fire hit the flexicoker unit of Venezuela's 645,000 barrel per day Amuay refinery on Wednesday, but no one was hurt and firemen brought the blaze under control.
The oil workers union at the huge facility said the flexicoker unit had been stopped a day earlier due to a fault.
"A pipeline broke and caused an explosion and fire, which is now under control. The (flexicoker) plant was stopped yesterday because of a fault in its compressor," said Ivan Freites, president of the workers union at the refinery.
State oil company PDVSA confirmed the small explosion and said no one had been hurt.
Last week an internal report by PDVSA showed that Amuay, Venezuela's biggest refinery, had returned to operating at its normal level, 10 months after an explosion that killed more than 40 people.
The facility has had problems at various units since the blast, including at its flexicoker plant.
The internal report said 10 of Amuay's 51 plants were out of action, including its lubricants plant. The refinery's biggest distillation unit, no. 5, restarted in April after being badly damaged in August's deadly explosion.
(Additional reporting by Marianna Parraga in Caracas; Writing by Brian Ellsworth and Daniel Wallis; Editing by Toni Reinhold)