Tragedy struck on the night shift. With no emergency exits and hundreds of Pakistani workers crammed into a dilapidated factory, the building became an inferno in minutes, where 289 people suffocated or burnt to death.
The 1,200 registered employees at Ali Enterprises on the Hub River Road Karachi SITE (Sindh Industrial Trading Estate) made ready-to-wear clothing dispatched across the country and exported abroad, including to Britain.
But on Tuesday night profits turned to ashes with the worst ever industrial fire in the history of Pakistan adding to the litany of woes that face the nuclear-armed country on the frontline of the war on Al-Qaeda.
It remains unclear how the inferno began.
Desperate relatives ran to the scene, scuffling with police and watching as flames swallowed the building, forcing dozens to jump from the upper storeys into the street as others stood on the roof, sobbing to be rescued.
Behind the flames and smoke, a dead body was seen stuck to a window, as if the victim had been trying to jump from the second floor, but just didn't make it in time, said an AFP photographer.
"I just received a call from inside. They are still alive, please do something," one relative shouted at a rescue worker outside.
"They are dying. Oh, media people why are you silent, please, please do something," shouted another at the sea of photographers, cameramen and reporters covering the accident.
Many workers burnt to death, others suffocated or succumbed to the effects of the fire en route to hospital.
Police sought to prevent panicked relatives from running into the blazing factory.
"This building can collapse at any time, you can see the cracks," a rescue worker shouted in an effort to keep them back.
At the Civil Hospital hundreds of grieving relatives desperately searched for mothers, fathers, brothers, sisters, sons and daughters among the dozens of badly mutilated bodies, burnt beyond recognition.
Mohammad Yaqoob, who should have been working on Tuesday but called in sick, was unable to find his younger brother, Mehtab Ali, among those who perished.
"I have seen many bodies but could not identify any of them. They are badly charred. You need strong nerves to see all of them, which I don't have," he said, wiping tears from his eyes.
The 40-year-old had been going to a nearby clinic when he heard about the fire.
"I ran there. I was worried about all the workers but my prime concern was for my younger brother who was on duty on the evening shift," he said.
"Some of them came out safely through (use of) the ropes and others were rescued by firefighters. Some of my colleagues even jumped from the windows and broke their limbs. But my brother was not among them."
Emergency wards and morgues in the city's two other major hospitals were also crowded with the people, crying and beating their chests. Some of them had children with them -- some shocked, the rest weeping.
"I have come here to search for my sister," said Mohammad Ashraf.
"She is a mother of four. She earnt for her family to survive, but now we don't know where she is," he sobbed.
Relatives remained outside the factory until Wednesday evening, crying and praying, over what was described as the worst industrial accident in the history of Pakistan.
"I pray for my father. May Allah save him. I am waiting for a miracle, to see him come out smiling as he was when he left us while going to work last night," Azmat Ullah, 20, said.