A total of 13 workers were poisoned by carbon monoxide in a fire at a highway construction site close to the Three Gorge Dam in central China's Hubei Province Wednesday, the local government said.

A fire started at about 10 a.m. at a tunnel entrance being built as part of a expressway project adjacent to the Dam, according to the publicity department of Yichang City.

The 13 people working in the tunnel at the time of the accident were taken to hospital, where they are being treated for carbon monoxide poisoning and are in stable conditions.

An initial investigation found out that workers' errors triggered a fire in waterproof boards.

The project was temporarily called off for investigation.

Construction of the four-lane 58-km-long expressway, with a designed speed of 80 kilometers per hour, started in April last year and is expected to finish by the end of next year.

The project, involving 4 billion yuan (585.6 million U.S. dollars) in investment, is expected to ease the strain on cargo volumes through the Three Gorges Dam.

(Xinhua News Agency June 4, 2009)