Production has partially resumed at a refinery in northwestern Venezuela where an explosion last Saturday triggered a huge fire, caused significant material damage and killed at least 42 people, state oil company Petroleos de Venezuela S.A. said.

The production units have started up "gradually," a PDVSA spokesperson told Efe Friday, adding that work to get some processes up and running had started the day before.

The blast, which investigators suspect was caused by a gas leak, hit the Amuay refinery in the wee hours of Aug. 25, leaving nine fuel tanks in flames, causing damage to more than 1,200 nearby homes and paralyzing work at the facility.

The latest official report indicates 42 people died, eight remain missing and more than 100 required some degree of medical assistance as a result of the accident.

The 645,000-barrel-per-day refinery is one of three in the Paraguana Refinery Complex, one of the world's largest with a total refining capacity of 1 million bpd.

Oil Minister Rafael Ramirez, who also heads PDVSA, had said in recent days that the refinery shutdown would not affect fuel supplies for Venezuela or foreign markets, noting that the country has inventories of more than 4 million barrels of gasoline and other fuels, equivalent to a 10-day supply.

The fire affected one of the storage areas but not the units where the different refinery processes occur.

Eighteen National Guard members died in the accident at the complex, which has a base and housing for guardsmen, Vice President Elias Jaua said last weekend.

The investigation being conducted by the Attorney General's Office, the CICPC criminal investigations agency, the Sebin police intelligence agency and PDVSA specialists will "take the time needed," Attorney General Luisa Ortega Diaz told state-run media this week.

Chavez said Friday that the opposition was trying to use the tragedy to its advantage in the lead-up to the Oct. 7 presidential election.

Even before "we began recovering our dead," the opposition "was saying it was Chavez's fault, it was Rafael Ramirez's fault, that Chavez should resign and of course Rafael Ramirez," the leftist head of state said.

"Because the reason was lack of maintenance or because there was a gas leak for several days and no one paid any attention," said Chavez, who has vehemently denied any neglect on PDVSA's part.

On Monday, opposition candidate Henrique Capriles said the Amuay explosion reflected "the inefficiency and political maneuvering" of Chavez's government.

"We're not talking about rains or a natural event, but an accident that is the consequence of something," Capriles said.

Last weekend, the general secretary of the Futpv petroleum workers union, Ivan Freites, accused the government of neglecting maintenance work in the oil industry in recent years. EFE