(Recasts with refinery now being operational, adds comments by refining center)
By Mircely Guanipa
PUNTO FIJO, Venezuela, March 5 (Reuters) - A small fire broke out at Venezuela's 310,000 barrel-per-day Cardon refinery on Saturday but it was quickly put out and the refinery is operational, Venezuelan state oil company PDVSA said.
"A small fire in the AV3 plant of Cardon was extinguished," the Paraguana Refining Center (CRP) said on Twitter.
"The refinery is continuing with its operations thanks to our firemen," the refining center added, without providing further details.
The fire started in a pumping room, according to union boss and fierce PDVSA critic Ivan Freites.
One distillation unit was halted as a precaution, Freites added, meaning Cardon's gasoline-making fluid catalytic cracker (FCC) had to be reduced to 50,000 bpd from its previous level of roughly 60,000 bpd.
A worker inside Cardon, who asked to remain anonymous because he was not authorized to speak to the media, said the fire had been brought under control and there were no injuries. (Writing by Alexandra Ulmer; Editing by Tom Brown and Matthew Lewis)