TWO workers were killed and five others poisoned Tuesday by a gas leak at a construction site on a subway line in Guangzhou, according to the local safety work watchdog.

The accident occurred at around 6:15 p.m. between Donghu Station and Huanghuagang Station on Metro Line 6 when workers opened a shield machine for a routine check. An unidentified gas leaked out during the inspection.

A worker surnamed Bai said that the gas may have been acetylene, a substance that may cause dizziness, headache and nausea when inhaled.

A mixture of three to 82 percent of acetylene with air can explode on ignition.

One victim suffered more than 50 percent burns and three fractures, according to the doctor. Another man had a minor leg injury while one worker was injured in his right hand.

A total of 18 workers were working at the site when the accident happened in the capital of Guangdong Province.

The construction of Donghu Station, conducted by China Railway Tunnel Group Co., started June 8, 2006, and is expected to be completed Oct. 23 this year.

Construction was halted after the accident and an investigation is underway.

(SD-Agencies)