Hugo Chávez, the Venezuelan president, has angrily denied claims that early warning systems at the country's main Amuay oil refinery failed as residents reported there had been a strong smell of gas before Saturday's deadly explosion but no action was taken.
Three refining tanks exploded at Venezuela's biggest refinery complex, killing 41 people and injuring more than 80 people in the Opec nation's worst ever oil accident.
Officials at the 645,000 barrel-per-day Amuay refinery were on Sunday trying to stop the fire still raging at two storage tanks from spreading to other nearby fuel storage facilities. That would delay Amuay's restart beyond the current estimate of two days.
More than 200 homes were reported damaged by the shockwave. Some were across the street from the refinery, which is on a peninsula in the Caribbean Sea in western Venezuela.
Puddles of petroleum mixed with water covered roads in the area. The victims from Saturday's blast included 18 national guard troops and 15 civilians; six remained unidentified. On Sunday two of the dozens of people wounded died in hospital, a national guard general told reporters.
Chávez, who visited the scene on Sunday, said there were still several people unaccounted for, as well as at least 35 people still in hospital, so the death toll could rise.
As fire continued to burn on Sunday the president angrily denied claims that a strong smell of gas experienced by residents in the days preceding the explosion could have indicated a possible failure of the complex's warning system.
"What you say you heard suggests something that is practically impossible in an installation of this kind, the largest refinery in the world. It is completely automatised and it has thousands of responsible workers here day and night, civilians and military," Chávez said. "There is no way that there could have been a gas leak during three or four days and that no one did anything."
People living close to the refinery have spoken of a dense fog-like cloud descending in the days before the huge explosion, which sent a shockwave tearing through the surrounding area, shattering shops and homes and littering the streets with debris
"The smell of gas could be normal close to a refinery, especially on a windless day like Friday, but [this] wasn't," said Mario Theis, who worked as operations manager in the Amuay complex for more than 30 years. "At the first hint of a gas leak sirens should go off and all access roads get closed. It didn't happen."
The cause of the blast has yet to be determined but with presidential elections only six weeks away political accusations are flying. Chávez has said that a gas leak that concentrated into a cloud led to the explosion, while the general manager of the Paraguana refining integrated complex comprised of the Amuay and Cardon plants, Jesus Luongo, denied any negligence of maintenance practices.
This accident and a large oil spill in the eastern state of Monagas have revived allegations from industry professionals that safety protocols and standard maintenance practices were neglected after a general strike by the company's employees in 2002 led to the firing of more than 20,000 people.
According to Gente del Petroleo, an organisation of retired oil executives, since 2003 there have been 79 accidents in the Paraguana refining complex, where 19 workers have died and 67 have been gravely injured.
The blast ranks as one of the deadliest oil industry accidents in recent history, approaching the toll of the 1997 fire at Hindustan Petroleum's Visakhapatnam refinery in India that killed 56, and topping the 2005 BP Texas City refinery blast that killed 15 workers.
The state-owned PDVSA oil company is not only the lifeline of the country's economy but in recent years has moved away from its core business to operate social and housing projects for the government on a massive scale.
"In my time there we knew what the objectives of the oil industry were. Now PDVSA diverts its resources into politicking" said Theis.
According to the blogger Miguel Octavio, citing PDVSA's official 2011 annual report, the Amuay refinery was scheduled to undergo nine maintenance shutdowns but only two were conducted because of lack of parts.
Chávez, who has called for an extensive investigation into the cause of the explosion, suggested the reporting of the event could be playing into the opposition's political agenda. "I recommend to all those who claim this [lack of maintenance] not to speculate. This all coincides with a line of opinion being generated," he said.
On Saturday morning the energy minister, Rafael Ramirez, assured Venezuelans there was enough fuel in store to satisfy domestic demands and that the Amuay refinery would be operating in a maximum of two days.
But as the flames rose up in the night sky skeptics worried that what was already deemed a tragedy could worsen.
"The situation is not under control. They are waiting for the fuel to extinguish itself but the neighbouring [storage] sphere could very well be heating up," said Alexis Acosta, who had to flee the area because of the damage done to his house by the blast. "The safety valves might not stand the pressure."