Venezuela's government has not ruled out any theory in the investigation into the Aug. 25 explosion at the Amuay refinery that killed 42 people, but "there's no way" that the proper maintenance was neglected, Energy and Mines Minister Rafael Ramirez said Sunday.

"We cannot rule out any hypothesis. We're working on the basis that we need to clarify ... the origin of this situation," Ramirez said in an interview with journalist and former Vice President Jose Vicente Rangel on the private Televen channel.

"However, there are things that can be ruled out," the minister said.

Among those is the version given by several residents in the area affected by the blast, which local media played up, about an alleged gas leak over several days prior to the explosion, Ramirez said.

"That is a complete lie. It's not possible for this to occur with all the detection mechanisms we have at the refinery," Ramirez, who is also CEO of state-owned Petroleos de Venezuela, or PDVSA, said.

Regarding the hypothesis that the blast occurred due to negligence, Ramirez said that "there's no way that we could (not perform) the maintenance at installations as complex as this."

Between 2007 and 2012, PDVSA invested $6 billion in the maintenance of its refineries and, just in July of this year, $4.3 billion was poured into the Paraguana Refinery Center, or CRP, in the northwestern part of the country where Amuay is located, the minister said.

"We don't want to avoid any responsibility but, without a doubt, we can't be naive and here we have to investigate everything," the minister said in response to a question from Rangel about possible sabotage.

The petroleum industry "is subject to threats and has been attacked on an ongoing basis," Ramirez said, referring to the fact that the sector was shut down from December 2002 to January 2003.

"It has become a target for the enemies ... of the country, a war objective," Ramirez said.

The Amuay refinery, one of the three in the Paraguana Refinery Complex, was rocked by an explosion on Saturday, Aug. 25, that killed 42 people and injured 132.

The blast damaged 500 nearby buildings and started a fire that burned for four days and affected nine fuel tanks at the facility.

Eighteen National Guard members died in the accident at the complex, which has a base and housing for guardsmen. EFE