Four workers died after being exposed to toxic gas while cleaning a sewer line in the Faisalabad Industrial Estate Development and Management Company (FIEDMC) area,24NewsHD TV reported on Friday.
According to initial reports, the workers were carrying out routine sewer-cleaning operations when they were overcome by poisonous gases inside the drainage system.
The incident resulted in the deaths of all four labourers.
Rescue teams and local authorities responded to the scene and shifted the bodies to a mortuary unit for legal and medical procedures.
Officials said all four deceased workers belonged to the northwestern district of Lakki Marwat.
Authorities said the bodies would be transported to their hometown in Lakki Marwat for burial after the completion of post-mortem and other formalities.