Killer Lakes

When Mount Nyiragongo erupted in the Democratic Republic of Congo in January 2002 it seemed like a disaster. Molten lava plunged down the hillside and poured into nearby Lake Kivu. Many died, and much of the city of Goma was destroyed. In fact, the local people were lucky. Had the eruption spread to one of the many volcanic faults under Lake Kivu, it could have unleashed one of the most terrifying of all natural phenomena - lake overturn.


Death by suffocation

The phenomenon of lake overturn first struck in 1984 at Lake Monoun, in Cameroon. 37 people mysteriously died, suddenly and silently. A bizarre array of theories sprang up - secret testing of chemical weapons, a massacre by unknown terrorists; none really made sense. The scientists who looked into the disaster believed it had to be something to do with the lake itself, but they could not be absolutely sure.

In 1986, before research into the Monoun disaster was made public, it all happened again. The tragedy of Lake Nyos, also in Cameroon, made headlines around the world when almost 1,800 people sleeping in houses around the lake suffocated in their sleep. The team of scientists that went to investigate concluded that carbon dioxide, trapped at the bottom of the lake, had suddenly risen to the surface, killing everything within 25km. They called their theory lake overturn.
Releasing the pressure

Eventually the scientists came to realise that carbon dioxide(CO2) springs underground were pumping carbon dioxide into the lake and that the whole tragedy would be repeated if nothing was done. They installed an extraordinary fountain in the middle of the lake to help the gas disperse. Even so, the level of carbon dioxide in the waters remains a concern.

The Nyos disaster promoted a survey of deep lakes in Africa and Indonesia to see where else lake overturn could happen. All seem to be safe, except one - Lake Kivu, in Rwanda. Lake Kivu is one of the largest and deepest lakes in Africa and two million people live around its shore. It is also filling up with carbon dioxide, although it's not yet saturated with the deadly gas. The only thing that could trigger a gas release would be a massive geological event. Worryingly, Lake Kivu is sitting in an earthquake zone and surrounded by active volcanoes, including Mount Nyiragongo. If an eruption or an earthquake was to happen under the lake, then the effect could release millions of tons of asphyxiating gas into the surrounding areas. Until a solution is found, millions of lives could be at risk.

1985: Gas blast kills eight in Putney

10 January 1985 Eight people have been killed in an explosion in a prestigious block of flats in Putney, south-west London.
Dozens were also injured when the blast demolished Newnham House, a three-storey block of six flats on Manor Fields Estate in Putney Hill.

The blast has been compared to a 50lb bomb going off and has caused an estimated £250m worth of damage.

It is believed that the accident, which happened at 0715 GMT, was caused by a fractured cast iron main pipe below ground.

A number of residents smelt gas in their flats in the morning and contacted South East Gas Board.

In Context
Flats on the exclusive Manor Field estate were worth around £100,000 before the accident. Hours after the blast, police had to chase away looters who were trying to pick spoils from the ruins.
Police found a collection of plastic bags stuffed with £20 notes totalling thousands of pounds, among the debris.

In the immediate aftermath of the disaster, some residents claimed that it was linked to problems with a central heating system installed three years earlier. They complained that they had contacted the gas board on several occasions about possible gas leaks.

A government report concluded that the explosion was caused by gas leaking into the building from a crack in a cast-iron gas main.

An earlier government report had recommended that all cast iron pipes be replaced with PVC pipes. Before the blast, more than half of Britain's mains pipes, including those at Newnham, were still in cast iron.

Scotland Disaster

1988: Piper Alpha oil rig ablaze
A fire on a North Sea oil rig is feared to have claimed the lives of most of those on board.

The fire is believed to have started after explosions at about 2230 BST (2130 GMT) on the Piper Alpha drilling platform, 120 miles (193km) off the north-east coast of Scotland.

Helicopters and boats were immediately sent out to rescue the oil workers in an operation co-ordinated by the Aberdeen coastguard.

Pilots reported seeing an "inferno" up to 350ft (107m) high and a platform wrenched apart.

It is thought approximately 225 men were working on the rig owned by Occidental Oil.

Tragidy
A total of 167 people died in the Piper Alpha fire making it the world's worst offshore oil disaster.

Ukrainian mine disaster

Eighty die in Ukrainian mine disaster
Sunday, 12 March, 2000
In a coalmine in eastern Ukraine where eighty miners died in a methane gas(CH4) explosion.
It was the worst in a series of mine disasters in Ukraine since the country became independent when the Soviet Union broke up.

Belgium gas blast

Fifteen die in Belgium gas blast
A huge gas explosion in Belgium has killed 18 people and injured 120, many of them with serious burns.
The blast, at an industrial park about 30km (20 miles) south-west of Brussels, sent flames shooting into the air, and was felt over a wide area.
fire service spokesman at the scene near the town of Ath said the site of the explosion looked like a war zone.

Emergency services treated the blast as a major incident and troops helped with the disaster response.

A nearby motorway was closed and local residents were advised to stay indoors with their windows closed.

Fire at Australian gas plant

A series of explosions has severely damaged a gas processing plant in the Australian state of Victoria.
Two people were dead, and eight others were injured, one of them critically, according to officials.

About five blasts at the Esso plant at Sale, about 180km (110 miles) east of Melbourne, were followed by a large fire.

The plant, which supplies all gas and crude oil for Victoria, has been shut down.

"The air was filled completely with dense black smoke and flames,"
said Elizabeth McGuinness, who runs a glass and security door store a few kilometres away from the site.

Gas Disaster in China

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.