The deadly factory fires in Karachi and Lahore are sadly not uncommon in Pakistan. Rarely does a month go by when some sort of preventable workplace accident not make the headlines.

But the Karachi blaze is different.

Close to 300 people lost their lives, making it one of the deadliest industrial accidents in Pakistan's history. The five-storey building, where 1,500 people reportedly worked, had only one exit and most of the windows were barred shut forcing many to find safety wherever they could.

Mohammad Ishaq, a witness, said: "I was watching the stranded people on the roof. The fire was raging and people started jumping from the top floor."

Local media showed the uncensored scenes of horror, scenes only matched by the dozens of charred bodies recovered from inside the factory.

So enormous was the blaze, it took 40 fire vehicles several hours to contain the flames.

Ehtishamuddin Siddiqui, Karachi's chief fire officer, said the factory could collapse at any time as it had been so damaged by the fire, and media footage showed huge cracks all over the building.

Dozens of ambulances were called in to ferry the dead and injured to local hospitals.

Health officials had to store remains in storage rooms after morgues reached capacity.

Keeping vigil

Grieving family members kept vigil outside waiting to hear whether their loved one had been identified or not.

Mohammad Hussain Syed, a Karachi city official, said: "Some bodies are completely burnt and cannot be recognised. It is only possible through DNA tests. It was a big garment factory where lots of people were working. That's why it will be difficult for us to assess how many have come out safely and how many were trapped."

The Karachi blaze erupted only hours after a similar fire at a shoe-making factory in Lahore in which 25 people were killed.

That factory was in a heavily built-up residential area and media reports suggest it was operating illegally.

Both tragedies raise familiar questions about why more isn't being done to prevent workplace accidents and why the government isn't enforcing its safety laws.

Raja Pervez Ashraf, prime minister, expressed his "shock and grief" over the deaths in both cities and has ordered an investigation.

But many labour rights activists say that isn't enough.

They want concrete measures put in place to protect workers and assurances tragedies like these never happen again.