Manila, Philippines - Salve Descallar wiped away her tears as she awaited the fate of her missing husband, a day after one of the Philippines' deadliest fires devoured a sandals factory in Manila, killing at least 72 people, and sparking angry calls for strict implementation of safety regulations in the country.

As Descallar and her son stood under the mid-afternoon sun, near the burned-out rubber sandals factory, ambulances carrying body bags with the charred remains of the victims slowly made their way through the police cordon. With no clear information from the local government, or the owners of the factory, it was hard for Descallar to know if her husband was one of those who had died, or rushed out for treatment.

"We have already gone to all the hospitals in this area, and we still couldn't find him. But who knows, maybe he was brought elsewhere," Descallar told Al Jazeera on Thursday, as she pleaded for help from authorities. Family members of other missing factory workers also gathered nearby with worried faces and many questions.

Cause of the fire

Descallar's husband, Jony, 52, was the manager at Kentex Manufacturing Corp., which makes high-end rubber sandals. Just before the fire broke out on Wednesday, Descallar recalled asking her husband on the phone, why someone was welding next to the factory's chemical storage room.

"He assured me that the work was under supervision, and that the welders knew what they were doing. And then this thing happened," Descallar said. Her account of events was consistent with what police investigators told the media, that the spark from the welding may have triggered the stored chemicals to explode and burst into fire.

Just seconds after the explosion, the fire started to spread throughout the 3,000 square-metre building, and the thick black smoke prevented those who were inside from escaping quickly, Zenaida Manibog, the operator of the company canteen, told Al Jazeera. She managed to escape with her son and seven-year-old grandson.

"We couldn't see anything. We just held on to each other as we made our way through the smoke. We could hardly breathe. I thought that was the end for us," she said, as she showed to Al Jazeera the lacerations in her grandson Neil Patrick’s feet.

Manibog's 26-year-old son, Sean, said the fire spread with such intensity it was almost impossible for the workers at the assembly section on the second floor to escape. The explosion that first hit the building entrance also blocked the staircase, the quickest escape route for the workers.

It took at least 15 more minutes for the first batch of fire fighters to arrive, Edgar Gonzales, a worker at a nearby car parts storage facility, told Al Jazeera.

"I could hear people screaming from inside. Then it fell silent. One worker managed to jump out from the burning platform near the entrance staircase," he said.

It took firefighters from all over the capital almost seven hours to extinguish the fire.

Several witnesses told Al Jazeera that some of the survivors had to climb up the three-metre high perimetre walls to escape. Most of them had bruises on their hands and legs, as the edges of the walls were encrusted with broken glasses, a common feature among many walled buildings in the Philippines, installed to ward off burglars.

Most of the workers, however, perished in the blaze.

Unrecognisable remains

Human remains inside one body bag were unrecognisable, and appeared only as lumps of burned charcoal.

According to the Philippine Interior Minister Manuel Roxas, fire investigators found 69 bodies gathered in just one corner of the building.

On Thursday, Roxas announced an investigation into the fire, saying that "it was not right" that 72 people had to die. He also sacked the local fire marshall.

"What I can do for the families of the victims is to find out what really happened and go after those who are responsible. We will make them accountable for this incident," Roxas said after touring the factory.

In a statement, the Philippine labour ministry said the company was "compliant with occupational safety requirements as of September 2014". Ulysses Aguilar, a top aide to the mayor of Valenzuela, where the fire broke out, also told Al Jazeera that the factory was in compliance with local regulations.

But for Dionisio Candido, 62, the assurances from the government were no consolation. He lost his 18-year-old daughter Rosalie, her partner and two other relatives, all workers at the factory.

"How can you escape from that building, when even the windows have fixed iron frames? A cat can't even make escape from there."

It was unclear if the building had fire exits. But at least two security personnel guarding the building told Al Jazeera that the factory had none. It was also unclear if the workers had undergone fire safety drills.

Fires in the Philippines are frequently blamed on the lax implementation of safety rules. In 1996, a fire hit a dance club in another Manila suburb, killing at least 160 people, and is considered the deadliest in the country.

Source: Al Jazeera