Four coal miners died from suffocation due to the presence of poisonous gas inside a coal mine in Quetta's Sanjdi area on Friday morning.

Rescue officials said that two other miners fell unconscious when the Sanjdi coal mine in suburbs of Quetta was filled with poisonous gas.

Rescue workers retrieved the bodies of the coal miners and shifted the unconscious men to nearby hospital for medical treatment.

The miners were working thousands of feet deep inside the mine when suddenly the poisonous gas filled the space, rescue workers said.

All four victims belonged to the Ghorband area in Swat's Shangla district and are members of one family, locals in Shangla told Dawn, adding that their bodies would reach the area on Saturday.

"Working conditions for miners are very poor," Bakht Nawab, a labour leader said while speaking to DawnNews. "Neither are they compensated nor are they provided proper protective gear for working inside mines."

Officials of the Balochistan Mines and Mineral Department also reached the spot to look into the incident.

Such untoward incidents are known to occur in the coal mines of Balochistan. According to labour union members, the lack of safety arrangements always lead to deaths of poverty-hit miners. The death toll of coal miners hailing from Shangla from 2010 to 2017 is more than 200.

Most of the miners working in Balochistan hail from Khyber Pakhtunkhawa or are Afghan nationals.

With additional reporting by Umar Bacha.