Explosive change for a woman at the top

Edith Sia Siu-ping used to dress for the office and spend her days managing external relations for her construction company in comfort and safety. Now she is handling explosives and drills beside the men working on Hong Kong's deepest tunnel-blasting project - the Harbour Area Treatment Scheme.

This is the deepest tunnel construction project in Hong Kong so far, with depths ranging from 70 metres to a maximum of 160 metres below sea level in North Point, where Sia is stationed.

Sia (pictured) was encouraged by a previous supervisor to attend a blasting-work training course for supervisors. With a bachelor's degree in civil engineering and a master's in construction management, she was keen to return to hands-on work.

'I was interested in how a construction site worked,' she said. 'It was a very rare opportunity for me to work on such a meaningful project.'

The scheme is intended to improve the water quality of Hong Kong's harbour by channelling and treating sewage rather than discharging it untreated.

Work on the scheme has entered its second and final phase.

Commissioned in 2009, the scheme involves blasting 21 kilometres of tunnels around the perimeter of the city and under Victoria Harbour. These tunnels will be used to collect sewage from the northern and southwestern areas of Hong Kong Island, then the waste will be transferred to a sewage treatment plant on Stonecutters Island. The project is due to be completed in 2014.

In the past, women were barred from working in the construction industry because it was traditionally seen as a purely male preserve. That, and a naturally harsh working environment, helped entrench the idea that construction and engineering was a male-only profession.

Yet as Hong Kong becomes progressively more liberal regarding sexual equality, opportunities for women to work in engineering - including blasting tunnels - have slowly increased.

'What a lot of men can do, women can do now as well,' said Sia.