More than two-thirds of workers have been exposed to excessive heat while doing their jobs, according to a new U.N. report, but few countries have taken steps to protect them as climate change makes heatwaves more frequent and intense.

Nearly 19,000 people die every year due to workplace injuries attributed to excessive heat, and an estimated 26.2 million people are living with chronic kidney diseases linked to workplace heat stress, according to this month's report by the U.N.'s International Labour Organization (ILO)…

People working outside are among those most at risk from extreme heat - from farm labourers to construction workers and gig workers, who often lack regular breaks or access to drinking water while out delivering orders.

"Food delivery drivers have heart attacks when it's hot outside ... We need to think of that in the context of climate change," said Oğuz Alyanak, a researcher at Fairwork, a gig research project at Britain's Oxford Internet Institute.

Inadequate cooling in the workplace can also pose problems for indoor workers such as domestic workers, teachers or garment factory employees…

Migrant workers hired to work outdoors in hot countries are another high-risk group, especially when they are not given time to acclimatise, said Manal Azzi, an occupational safety and health safety expert at the ILO and the study's lead author…