PUNTO FIJO, Venezuela (AP) -- After nightfall on Friday, as red lights began glowing atop the massive Amuay refinery in western Venezuela, the odor of sulfur made its way through the surrounding neighborhood of working-class homes and small shops.
Francisco Gonzalez, a stocky accountant with dark hair, noticed the smell after 7 p.m. as he climbed the stairs to his second-story apartment across the street from the refinery. He had smelled the fumes from gas leaks many times before, so he didn't think much about it as he shut the door.
Six hours later, disaster struck. A powerful explosion ripped through the neighborhood and engulfed part of the refinery in flames, killing at least 39 people and injuring more than 80 in Venezuela's deadliest refinery blast ever.
"The first thing I saw was that the apartment didn't have windows or doors or walls, just a floor and a roof," Gonzalez said. "I don't know how we survived."
In the dark, the 31-year-old man made his way downstairs to the street, where he, his brother and sister-in-law joined terrified neighbors. Some were wounded. Others were shouting.
When Gonzalez looked at the back of his right hand, it was bleeding from gashes.
At about 2 a.m., the halls of the hospital were filling up with wounded people. Doctors and nurses hurried to treat the most seriously hurt, while Gonzalez and others sat on the floor waiting their turn.
Back at the refinery, soldiers, firefighters and state oil company workers were diving into action. Bodies were pulled from the rubble and lifted onto pickup trucks.
Stella Lugo, the governor of Falcon state, went on state television to update the nation, setting the initial toll at seven people dead and 48 injured. The toll steadily rose in the next hours.
When she reached the refinery at dawn, Lugo posted a photo on Twitter showing balls of fire and black smoke billowing.
Other government officials went on television saying the gas leak had led to the blast and that the fire was being brought under control. President Hugo Chavez ordered an investigation and declared three days of mourning in the country.
A total of 209 homes and 11 businesses were damaged in the explosion, and a National Guard post next to the refinery was destroyed, Vice President Elias Jaua said on Saturday. He said 18 of the victims were National Guard soldiers.
On Saturday night, dozens of people who had fled their homes in the neighborhood of La Pastora returned to streets covered with rubble, twisted scraps of metal and puddles of spilled fuel.
Gabriela Nunez, a housewife, went back to her home to gather belongings, saying she was worried about looters who had stolen goods from nearby stores hours after the explosion.
"That forced us to come back, even though we're afraid, to save what can be saved and secure our houses," Nunez said.
More than a day after the blast, the flames were still raging on Sunday, sending up a column of dark smoke.
Some oil experts and government critics were also raising questions, saying they believe there hasn't been sufficient maintenance at refineries and that the situation could be making such incidents more likely.
Refinery manager Jesus Luongo denied that, as did Chavez, who spoke to journalists near the refinery on Sunday.
The president said investigators haven't determined what caused the disaster.
"Lack of maintenance? Who can, who can say that right now with any seriousness? Nobody," Chavez said. He said he had spoken personally with some of the military officers who were on duty at the time.
"They tell me that very night, in the rounds that were made a few hours earlier, no substantial leak was detected," said Chavez, who later visited the refinery complex and attended a Mass for the victims.
Amuay is among the world's largest refineries and is part of the Paraguana Refinery Complex, which also includes the adjacent Cardon refinery. Together, the refineries process about 900,000 barrels of crude per day and 200,000 barrels of gasoline.
Oil Minister Rafael Ramirez said the country has enough fuel in storage, "10 days of inventories," to keep the Venezuelan market fully supplied. He said fires were still burning in two fuel storage tanks but that other "process areas" of the refinery were otherwise unaffected.
Once the flames are completely extinguished, Ramirez said, "we have the ability to restart our refinery in two days."
Restarting will be a challenge for Gonzalez, who picked through what remained of his family's apartment, sweeping away debris with a broom. Broken glass littered the floor along with fragments of the shattered walls.
The shop on the first floor was also destroyed, but Gonzalez and his brother and sister-in-law all survived with only minor injuries.
"I'm happy to be here telling this story," Gonzalez said, his hand covered in a bandage and with stitches on his arms. "Material things, although they cost us a great deal to obtain, aren't worth much when you compare them with life."
Associated Press writers Ian James and Christopher Toothaker, in Caracas, contributed to this report.