A burst gas well spewed toxic fumes killing nearly 230 people : In China one more disaster occure due to chemical gas. A burst gas well spewed toxic fumes killing 230 people, Nearly 10,000 people were taken to hospitals suffering from poisoning and burns following Tuesday's blast.
'Zone of death'
It was China's worst industrial accident - described by Chinese media as a "zone of death".
Engineers on Saturday pumped 480 cubic metres of concrete into the well to seal it. But they need to wait for the concrete to dry until they can be sure there are no more leaks.
The BBC's Francis Markus in Shanghai says the region's climate is very foggy and it could take some time for the sulphurous gas to dissipate.
The work to seal the well had been delayed on Friday as the rescue operation continued and because of safety concerns.
Emergency teams had set the well alight to burn off the poison gas as a stopgap measure.
"Go all out to rescue victims, prevent poisonous gas from spreading further and reduce casualties"-President Hu Jintao
Many of the confirmed dead are children or elderly people who were unable to flee after the explosion.
A local newspaper in Chongqing described peasants racing to get away after catching "a whiff of the smell of stinky duck eggs" - deadly sulphurated hydrogen.
Those who did not escape in time - including farm animals and fish - suffered burns to their skin and lungs from the gas.
China is notorious for dangerous working conditions at industrial plants.