A series of forklift incidents in the United States and Singapore in the last week left four people dead and 15 in hospital, according to local news reports.

In Craven County, North Carolina, an unnamed male employee at a Weyerhaeuser sawmill died after becoming trapped under the forklift he was working on, while in Woodford County, Kentucky, 40-year-old Lisa Hofmann of Pekin died after being struck by a forklift at a Case IH plant in Goodfield.

In Kinsman, Ohio, 37-year-old Jennifer Plant died after being pinned between a semi-trailer and a forklift while working at the McGill Septic Tank Company.

In Singapore, a migrant worker from Bangladesh died in hospital after being hit by a forklift at Beng Cheng Metal in the industrial suburb of Sungei Kadut, according to the Straits Times.

Biswas Sanjay Kumar, 37, died in the Ng Teng Fong General Hospital on April 22, six days after the accident.

On the morning of the accident, Kumar, who had only worked at the salvage yard for a month, was shouting instructions to a forklift driver who was lifting a bag of scrap metal when he suddenly went quiet, the news outlet said.

When the driver checked, he found Kumar on the ground with neck wounds.

All four forklift fatalities are being investigated by workplace safety authorities.

Meanwhile, in Goodyear, Arizona, more than a dozen people were hospitalised after being exposed to fumes from an overheated forklift battery.

According to a www.abc15.com report, the Goodyear Fire Department were called to a warehouse on 25 April after reports workers had been exposed to an unknown substance.

The report says 30 people were treated at the scene and 15 people were taken to a hospital, all in stable conditions.