This is up from the previous estimate of 666,000, and almost double the number of fatal workplace accidents.
The research was carried out by the International Labour Organization, ministries in Finland and Singapore, the Workplace Safety and Health Institute (WSHI) in Singapore, the Finnish Institute of Occupational Health, the International Commission on Occupational Health and the European Occupational Safety and Health Agency.
The updated figure is based on "better available data gathered and analysed by the research consortium", they said.
Their findings were revealed yesterday (4 September) at the World Congress on Safety and Health at Work in Singapore, where delegates heard that 2.78 million work-related deaths occur every year worldwide.
Around 380,000 of these are fatal accidents; the other 2.4 million are caused by occupational diseases, including cancer.
Dr Jukka Takala, senior consultant to Singapore's Ministry of Manpower, said: "There are many cost-effective ways that organisations can protect staff from exposure. Now it is time for action. People should be able to do their work without being out at risk."
IOSH president Graham Parker added: "The findings from this new research are truly shocking. It shows that 742,000 families have to come to terms with the loss of a loved one through cancer caused by something they were exposed to at work.
"We have been encouraged by the number of organisations which have supported or pledged to No Time to Lose, showing a real desire to protect their employees. But, clearly, more needs to be done."
Since its launch in November 2014, more than 100 organisations have made a pledge to IOSH's No Time to Lose drive, meaning they will look at reducing worker exposure to carcinogens. The campaign also has more than 200 supporting organisations.