Hong Kong authorities have stepped up measures to help protect outdoor workers at risk of heatstroke by providing subsidies to employers who want to purchase cooling equipment, as the city issued its fourth “very hot weather” warning in less than a week.

The announcement on Thursday followed the death of a 42-year-old worker who reportedly suffered heatstroke and fainted at a construction site the day before. He was pronounced dead at Prince of Wales Hospital in Sha Tin on Wednesday.

The worker’s distraught father cried as he told local media: “I still do not know … why I suddenly lost my son.”

The city has seen several steamy days since last Saturday, with the Hong Kong Observatory issuing four “very hot weather” warning signals within six days. Parts of the New Territories recorded temperatures of more than 33 degrees Celsius (91.4 Fahrenheit) on Wednesday, while some areas rose to 35 degrees on Thursday afternoon.

The Labour Department issued an amber heat stress warning from 1.30pm to 4.30pm on Thursday, alerting outdoor workers of different job types to rest for 15 to 45 minutes every hour.

Deputy Commissioner for Labour Vincent Fung Hao-yin said that heatstroke was preventable if employers took appropriate measures to help workers cool down.

“We endeavour to provide possible solutions to [the employers], for instance, the Occupational Safety and Health Council has provided a lot of services and discounts for heatstroke prevention supplies,” he said.

The department had partnered with the council to launch a “cooling products sponsorship scheme” to provide subsidies to firms that hired outdoor workers exposed to higher levels of heat stress.

The council’s executive director, Bonnie Yau Man, said employers could apply for the subsidy and buy cooling vests and solar fans at a discounted price of around 70 per cent off.

Yau encouraged employers to set up cooling kiosks at remote sites where it was difficult for workers to find shade or shelter.

She added that having equipment as simple as tubs of cold water for workers to soak their arms in could quite effectively bring down their body temperature.

There are about 130 kiosks in operation across the city, according to Fung.

The deputy commissioner said he was saddened by the death of the construction worker on Wednesday, adding the department had launched an investigation.

But he said that the employer in charge of the construction site had put in place necessary measures to prevent heatstroke and the affected employee had been working in the shade, according to preliminary checks.

Fung also addressed criticism over the accuracy of the Observatory’s calculation of heat levels based on two detectors – one in King’s Park Meteorological Station in Tsim Sha Tsui and another along the Beas River in Sheung Shui – saying the index should be taken as an “overall” reference.

“We do not object to the site managers conducting their own measurements in their own ways,” he said.

The department recorded about 30 industrial incidents related to heatstroke last year, according to official data.

Fung noted the city’s three-tier heat stress warning system – comprising amber, red and black signals – was improved last year and minimised the chances of repetitive warnings that caused public confusion.

He said he noticed that employers were largely aware when alerts were issued and gave breaks to their workers in accordance with guidelines.

The department issued 1,031 warnings to worksite managers during their inspections between May and October last year.

Fung said most of the employers who had been warned had taken action to ensure heat prevention measures at their sites met authorities’ requirements.