Local authorities say the pollution threat from the Vinylon chemical factory explosion has been contained

By Hepeng Jia/Beijing, China

The most serious chemical factory explosion to occur China for over a decade has not caused major damage to the environment, according to local authorities.

The 26 August blasts at a chemical plant in Hechi city in southern China’s Guangxi Zhuang Autonomous Region have killed 20 workers and seriously injured another 60. More than 15,000 workers, their families and nearby residents were evacuated.

Guangxi Vinylon Group, which owns the plant, was not available for comment. The state-owned firm mainly produces chemicals such as carbide, vinyl acetate and polyvinyl alcohol for adhesives and paints.

But the Hechi municipal government has posted regular updates on rescue efforts - which ended on 28 August - and the results of environmental tests on its website. Local rescue workers have safely removed tanks containing 900 tonnes of alcohols, two tonnes of liquid ammonia and three tonnes of liquid chlorine.

According to reports on the municipal government’s website, 14 tonnes of activated carbon were released during the incident but four dams erected by the authorities prevented polluted water from flowing into the local Longjiang river. 

Ge Xianmin, Guangxi’s toxic substances emergency centre director, told Xinhua, the official Chinese news agency, that chemicals manufactured in the plant included acetylene, ethylene, methanol, vinyl acetate and polyvinyl alcohol, which would mostly produce non-toxic carbon dioxide after combustion, and very small amounts of carbon monoxide. Ge also said that any chlorine released during the accident is likely to have been consumed during the blasts and subsequent fire.

In the past three days, the environmental monitoring station of Guangxi has reported normal levels of pH, COD (chemical oxygen demand), and the amounts of nitrogen and phosphorus and chlorine.

Sun Hongwen, deputy dean of Tianjin-based Nankai University’s College of Environmental Science and Engineering, says that China’s environmental agencies will now check for the presence of any other contaminants such as persistent organic pollutants (POPs). ’I have not heard of vinyl acetate and polyvinyl alcohol becoming POPs after burning,’ Sun told Chemistry World.

The Guangxi blast is one of several accidents to hit China’s chemical sector recently. On 7 June, a traffic accident in southwestern Yunnan Province caused 33.6 tonnes of hydroxybenzene to leak into the drinking water supply of 200,000 people in nearby Guangxi. On 12 June, a hydrogen sulfide leak at a fertiliser factory in Kunming, Yunnan Province, killed six people and injured another 12 people.