Mohammed Suman Miah died in Qatar on April 29, 2020 at the age of 34.

His death certificate, issued by the Qatari Ministry of Public Health four days later, described the cause of death as "acute heart failure [from] natural causes".

It provided no information on the underlying cause of death.

The death of the Bangladeshi migrant worker along with five others -- two from Bangladesh and three from Nepal -- are featured in detail in Amnesty International's recent report "In the Prime of Their Lives".

The report documented how Qatar routinely issued death certificates for migrant workers without conducting adequate investigations, instead attributing these deaths to "natural causes" or vaguely defined cardiac failures, Amnesty said.

In the course of the research, Amnesty identified cases of 18 deceased migrant workers in Bangladesh and Nepal, spoke with their family members and collected documentary evidence relating to their deaths in Qatar, including the death certificates issued by the Qatari Ministry of Public Health, the report said.

In 13 cases, the cause of death was reported as "natural death", two cases related to cardiac diseases and three to other causes -- a road traffic accident, poisoning and cancer.

Qatar authorities have failed to investigate the deaths of thousands of migrant workers over the past decade, despite evidence of links between premature deaths and unsafe working conditions, Amnesty said in a news release on Wednesday, marking the report's unveiling.

The report said of the six migrant workers, four were aged 34 when they died.

Mohammad Kaochar Khan, 34, a plasterer on a construction site, was found dead in his bed by his co-workers on November 15, 2017.

Security guard Yam Bahadur Rana, whose job involved long hours sitting in the sun, died suddenly at work on February 22, 2020.

Construction worker Suman collapsed and died at the end of a long shift in temperatures that had reached 38°C.

Tul Bahadur Gharti died in his sleep on May 28, 2020 after working outdoors for around 10 hours in temperatures of up to 39°C.

Pipe fitter on a project in the desert, Sujan Miah, 32, was found unresponsive by workmates in bed on September 24, 2020.

Truck driver Manjur Kha Pathan, 40, had been working 12 to 13 hours a day. He collapsed in his accommodation on February 9, 2021 and died before the ambulance arrived.

The report said while the time elapsed means it may now be difficult to prove whether each death was a direct result of their working conditions, all of them were regularly exposed to dangerous temperatures at work, and in every case Qatar failed to investigate their deaths or provide an opportunity for their families to be compensated.

It said the deaths of the six migrant workers highlight the personal tragedies for them and their families back home in Bangladesh or Nepal, as well as Qatar's failures relating to their deaths.

"They also symbolise the tragedies of so many others who went to Qatar to provide a better future for their families but came back in a coffin, and whose deaths remain unexplained," said the report.

One of the most well-documented and foreseeable risks to workers' life and health in Qatar is exposure to extreme heat and humidity, the report said.

However, between 2007 and May 2021, Qatar's main measure in place to try and mitigate such risks was a directive prohibiting outdoor work between 11:00 and 13:00 in the summer months, between June 15 and August 31.

UNEXPLAINED DEATHS

The death certificates of 15 out of the 18 cases reviewed by Amnesty International provided no information about the underlying causes of death, attributing the cause of death to "acute cardio respiratory failure due to natural causes", "acute heart failure natural causes", "heart failure unspecified" and "acute respiratory failure due to natural causes", the report said.

Dr David Bailey, a leading pathologist and member of the World Health Organisation (WHO) Working Group on death certification, told Amnesty International, "These are phrases that should not be included on a death certificate without a further qualification explaining the underlying cause.

"Essentially, everyone dies of respiratory or cardiac failure in the end and the phrases are meaningless without an explanation of a reason why.

"'Natural causes' is not a sufficient explanation."