Karachi: At least five people died in an industrial accident in the northern district of this city, when the boiler of an ice plant blew off the roof of the factory on Monday.

The roof of the factory caved in after the blast and the rescue workers said that about seven people got buried under concrete rubble. The five bodies were recovered from the ruins and shifted to the mortuary of a government hospital.

Witnesses said that the blast was so huge that not only it blew off the roof but badly shattered the walls of the factory, completely destroying the facility. The blast also smashed the glass panels of the windows of the houses in surrounding areas.

After the blast ammonia gas, which is used to make the ice, leaked all over the area, suffocating the residents and the passer-by. Several of the residents were taken to the hospitals because of asthmatic conditions.

Provincial home minister Anwer Sohail Sayal, ordered the police to reach the spot to help the rescue teams to take out the injured and clear the area. He also instructed the police to investigate the accident to see if an aspect of sabotage was found.

The media reported that the owner of the factory suffered a heart attack and was taken to the hospital.

Poor industrial laws and safety measures frequently cause fatal accidents in Karachi.

In past weeks, massive fire broke off at three different factories.

In 2012, a deadly fire at a garment factory took the lives of more than 260 people in the Baldia neighbourhood. Most of the deaths occurred as the workers could not get out of the factory, that was fortified from all over and had only one exit that was shut down by the security staff.