The reactor in one of the units lost its cooling water, heat built up, and radioactive gas burst out and spread all over Europe and parts of the USSR.

On the April 26, 1986, a nuclear power station at Chernobyl in the Ukraine, then part of the USSR, caused the world’s worst nuclear accident. The tragedy followed a routine maintenance operation when something terrible went wrong and radioactive gas drifted all over Europe. The disaster continued to claim more victims long after the accident disappeared from the public eye.

The Chernobyl nuclear power plant near Kiev in the Ukraine, formerly a state of the Soviet Union, was the pride of the country’s nuclear power program. It was the biggest installation of this kind with four generators, each producing one thousand megawatts of electricity, and two more of the same kind under construction. Construction of the first unit began in 1971 and by early in 1986, with four units operating, the Soviet government was about to launch a five-year program in which several new Chernobyl- style plants were to be built. The decision to go ahead was made in February of 1986 and the Communist Party Congress was to approve it in June of the same year. Between the two dates came the explosion of Chernobyl’s number four reactor.

The initial events were similar to accidents at other nuclear facilities. The reactor lost its cooling water and the nuclear fuel elements began to heat up. Action can be taken at this stage to bring in emergency supplies of water. Time is thus gained to locate the trouble and fix it. In the case of the Chernobyl accident, nothing was done to counter the buildup of heat and soon dangerous levels of radiation were being released into the atmosphere. The reactor did not have a protective building around it to prevent the escape of these radioactive gases. Finally, the heat level rose so high that graphite in the reactor core caught fire and a burst of radioactive material swept over the surrounding countryside devastating everything.

At the time of the accident the reactor was undergoing routine maintenance and that required a shutdown. The manager of the plant decided to conduct an experiment during this time, a test that could only be conducted during a shutdown. The manager wanted to know how he would deal with a reactor problem if power were unavailable from the main electrical grid. Even when a reactor is shut down it still requires power to maintain the cooling circuit. His experiment was to use diesel generators in such an emergency and he hoped that the fifty seconds or so that these engines required to come up to full speed would not jeopardize the operation.

No one knows exactly what went wrong with the experiment. We only know that the reactor heated up and then burst into flames. It happened in the middle of the night. A plume of radioactive material and radiation shot upward into the sky and then wind blew this cloud northwards across Poland and Scandinavia. A day later, Swedish technicians at a nuclear facility in that country picked up high levels of radioactivity. It was the remnants of a much thicker cloud that did most damage in the area immediately around the Chernobyl plant and second greatest damage as it passed over Belarus.

Nothing was said about the event at that time, nor was much revealed for days afterwards. Characteristic Soviet secrecy surrounded the event. Some reports were lost or destroyed. The Soviet Union was anxious to maintain a positive approach to nuclear sources of energy because there were plans to expand them. They did not want to arouse public fears. All this secrecy took place in the face of accurate information that was available to Soviet authorities telling them exactly how much radiation had reached any part of eastern or northern Europe. The Test Ban Treaty with the United States demanded that each side possessed the ability and the equipment to do this. In full knowledge of the terrible consequences of exposure to radiation, the Soviet Union refused to release what it knew until compelled by external evidence.

The staff at the plant attempted to assess the extent of the damage to unit four and to limit the spread of fire to the other reactor units. In doing so, many of these people averted what may have been a far greater catastrophe but also lost their lives as a result of lethal doses of radiation. Fire fighters risked their lives pouring water into the burning unit four reactor. Over a period of two weeks the Soviet Air Force dropped more than 10,000 tons of material into the reactor core to try and smother the fire. The pilots who flew on these missions died from the massive radiation doses they received and a dozen giant helicopters became so radioactive that they had to be dumped along with trucks, cars and other things around Chernobyl.

In a reactor core, when heat rises sufficiently high, hydrogen explosions occur. In unit four, explosions of this kind hurled burning lumps of graphite and reactor fuel into the air that then landed on neighboring buildings and set them on fire. Most of the buildings had tar roofs and this fueled the fires. Once the fires were extinguished there was the question of what to do with all the radioactive debris that had escaped from the reactor core. It was decided to gather as much as possible and push it back into the reactor. This dangerous task was at first undertaken by robots but these were soon found to be unable to cope with the terrain. They kept getting stuck so a fateful decision was made to use humans.

Choosing to use people for this task was tantamount to killing them. Everyone involved with nuclear installations knew by this time the deadly effects of radiation. The men, mostly from the army, were only able to work for a maximum of one minute even with heavy lead protective clothing on. Radiation levels were dangerously high. The one minute of work proved to be too much for some. They later succumbed to serious illness from their exposure to radiation. In total, almost one million men worked on the cleanup and the construction of a sarcophagus that would seal up unit four and stop the spread of radiation.

The sarcophagus consisted of a massive concrete container that would encircle the damaged reactor and form a roof on top. It took seven months to complete, was two hundred feet in height, and stretched for two hundred feet along each side of the reactor building. Construction was speedy and the quality of work correspondingly poor. Everyone wanted to minimize the workers’ exposure to radiation. The container was intended to last for thirty years but within a decade cracks and weaknesses appeared and repairs were needed. In addition, the concrete was gradually weakened by irradiation from within and tension from the huge temperature difference between inside and outside.

Scattered around the Chernobyl nuclear power plant were hundreds of dumps of radioactive waste. These usually consisted of open pits with linings of clay, containing anything from soil, timber, and vehicles to domestic items such as refrigerators and clothing. Some of the pits contained the remnants of the forest which surrounded the power station and absorbed so much radiation that the trees had to be destroyed and treated as radioactive waste. These pits became a big environmental hazard because they posed a threat to the main water table.

This water table is linked to the Dnieper River which supplied the water needs of thirty-five million people, including the residents of Kiev. Police and military personnel guarded the area around Chernobyl, ensuring that no one ventured close to lethal radiation. In spite of that, a few people, mostly the elderly, were allowed back into their old homes. They insisted that they could not see, taste, smell or touch the deadly radiation so it did not bother them. While they might not be concerned, future generations must. The long-term effects of radiation have yet to be understood. Such effects modify the genetic structures of animals, food, and humans.

The Chernobyl accident led to huge health problems in the Ukraine and elsewhere. Plant personnel, fire fighters, medical staff, and cleanup workers suffered the most. Reports from Belarus indicate a 50 percent drop in birth rates and a steady rise in miscarriages and birth defects. Other estimates claim that over three million Russians suffered radiation exposure with 370,000 likely to develop a radiation-linked illness. By 2001, estimates of total deaths from the Chernobyl accident totaled 15,000. On the wider scale of Europe other kinds of evidence mounted.

Researchers were able to counter the Soviet claim that no other country was affected by radiation from the accident. It was all propaganda, claimed the Soviets, when the countries of Western Europe refused to accept agricultural produce from Eastern Europe. Within a year, the evidence of widespread devastation was overwhelming and the USSR was forced to accept it. Scandinavia, Britain, West Germany, Italy, and all the countries in between had been hit with damaging radiation. A very large area had been contaminated.

Sweden was one of the hardest hit with much of the damage being carried in rain. An area of 4,040 square miles, 175 miles north of Stockholm, was so badly contaminated that all the grass had to be harvested and burned. Thousands of gallons of milk from this same area was poured away daily for some time. In the far north of Sweden, where the Lapp people live, levels of radiation was twelve times the permissible limit. These people were totally dependent on reindeer for almost everything they needed. The Swedish government helped pay the costs of destroying about 50,000 reindeer. To make matters worse, the vegetation of northern latitudes has a very slow rate of decay for radiation contamination. In 1987 it was estimated that much of the vegetation and soils of the Lapps will remain contaminated until the year 2030.

In December 2000, the last of Chernobyl’s four reactors was shut down permanently, the final act in a financial deal struck between western nations and the Ukraine. The nuclear power plant and an area extending outwards for nineteen miles in all directions became a wasteland as badly polluted as was Bikini (see Bikini Atoll, Marshall Islands, nuclear tests). Like Bikini it will remain a useless desert far beyond the lifetime of those who witnessed the original catastrophe.

The stone coffin erected around the plant at the time of the accident was still in disrepair in 2000. It had been built over the plant to prevent more radiation escaping and the work at that time was done at high speed and at enormous risk to all involved. To minimize the health hazard work shifts were limited to fifteen minute stints. Even fourteen years later, as the reactors were being closed down, repair men with special clothing to protect them from radiation could not stay on the roof longer than five minutes at a time. Radiation levels around cracks were seven times higher than the amounts regarded as unacceptably high.

Yellowstone is the oldest and perhaps most famous national park in the world. Established in 1872, it covers over two million acres of Wyoming and spreads into neighboring Idaho and Montana. Over the years it has gradually become valued not simply as a vast outdoor play area but also as a national treasure – it eventually gained the status of United Nations World Heritage Site in 1978.

Management of the park has long been a source of controversy. In recent times, locals were outraged to find that emissions from snowmobiles there were higher than in the traffic of downtown Los Angeles. Also the culling of more than 1,000 bison, mistakenly thought to be carrying livestock-threatening disease, was misguided to say the least.

However, nothing has stirred more debate than the management of naturally occurring fires in Yellowstone. Until the 1970s it had been the procedure of the Park Service to tackle and extinguish these spontaneous blazes. This interventionist policy enabled older trees to survive and dead ones to lie where they fell, storing up problems for the future. So much dead wood made the entire park a giant tinder box just waiting for the right conditions.

In 1988, the ideal forest fire conditions duly arrived. Spring had been relatively warm and dry and these conditions stretched into the summer. Multiple lightning strikes hit the park and, combined with the parched conditions and a strengthening wind, the park authorities found themselves dealing with huge wildfires that they could do little to control. Despite the best efforts of around firefighters who tackled the enormous conflagration from the air and on land, and the expenditure of nearly $120 million, the fires raged for months. On one August day alone, more than 600 sq km (232 sq mi) of Yellowstone were lost to fire, and cities downwind were covered in ash.

When: Summer of 1988

Where: Yellowstone National Park, USA

Death toll: There were two deaths outside the park attributed to the fires.

You should know: It is probable that the massive intervention by the authorities had little or no effect on the fires. In fact it may have harmed the area by introducing so much water which, combined with a subsequent wet spring, caused considerable soil erosion, while this level of wildfire occurs only about once in every 250 years, it is still part of the life cycle of the park. New vegetation has grown rapidly, seizing its chance to replace the old. In the decades following the fires the park has successfully regenerated.

Once a Chinese state enterprise, the Qinghe Special Steel Corporation had been transferred to the private sector before its plant in Tielng became the scene of a terrible accident in April 2007 – the worst to befall the modern Chinese steel industry. A large overhead ladle, that carried molten steel from a blast furnace, separated from its overhead track and fell. Instead of remaining upright, it hit a flatbed truck and tilted, spilling its deadly contents.

Some 25 tons of liquid steel at a temperature of 1,500°C (2,730°F) flowed out of the 2 m (6 ft) ladle, burst through the door of a meeting room where workers had assembled during an early-morning shift change and killed over 30 occupants. By some miracle, six workers who were out on the factory floor survived – they were able to turn and run, though all were badly burned and required prolonged hospitalization. Rescue services couldn’t gain access to the area until the intense heat cooled. The bodies they eventually recovered were too badly burned to be recognized and had to be identified through DNA testing.

There was public outrage when news of the tragedy broke. The authorities immediately sealed off the plant and launched a full investigation. The findings were not reassuring. It seemed that safety measures were poor, management was ineffective and the hoist that fell was not suitable for the job it was being asked to do. More significantly, the report concluded that this was not an isolated case of inefficiency, but indicative of a malaise that had spread throughout the Chinese steel industry. In a situation where steel making had to expand rapidly – perhaps too rapidly – to support the rapacious demands of a booming national economy, comers were being cut and a lax safety culture had become endemic.

When: April 18 2007

Where: Tieling, Liaoning Province, China

Death toll: 32 died

You should know: In the immediate aftermath of the Qinghe Special Steel Corporation disaster, the plant’s owner and three senior employees were arrested and charged with safety violations, while officials quickly offered generous compensation to bereaved families to ensure that public anger did not get out of hand.

Black gold has proved both a boon and a curse to the West African republic of Nigeria. The world’s eighth most populous country is a major oil producer, has membership of OPEC (Organization of the Petroleum Exporting Countries) and possesses huge proven reserves. However, constant agitation by the population of the oil-producing Niger Delta – concerned by pollution and central indifference to their needs – has meant that the government’s main source of income is constantly being disrupted by protest action.

Nor has this lucrative revenue stream transformed the lives of the country’s people, with many living in grinding poverty and shanty towns. To the inhabitants of Abule Egba in Lagos State, the overhead pipeline that carried petroleum products was a constant reminder of the valuable national resource that had somehow failed to transform their lives. Some resented it, and some decided to do something about it.

In 2006, around midnight on Christmas Day, thieves set out to give themselves a late present. They punctured the pipe and proceeded to help themselves to a large quantity of fuel before going on their way, possibly driving a full tanker, leaving behind a leaking pipeline. It may have been the small hours, but word spread quickly and soon hundreds of residents with assorted containers were trying to collect their share, amid pools of spilled fuel that formed beneath the breach.

At dawn, these were ignited and the pipeline exploded, causing a catastrophic fire. Numerous houses were destroyed, along with a church and mosque, and hundreds of people died. When the Nigerian Red Cross arrived to help, they were confronted with a scene of carnage. Charred corpses were scattered everywhere, though the team was able to find and help 65 seriously burned residents who survived the inferno.

When: December 26 2006

Where: Abule Egba, Lagos, Nigeria

Death toll: The number of casualties has never been officially established. After the event, an experienced Reuter’s news photographer did an approximate body count and came up with a figure of 500.

You should know: Abule Egba wasn’t the first pipeline disaster in Nigeria during 2006. Back in May a pressurized pipe at Atlas Creek Island was drilled by petrol thieves, the resultant explosion incinerating everyone within a 25 m (85 ft) radius and killing at least 150 people, many of whom were interred in a mass grave.

Silesia is Poland’s industrial heartland and the region’s coal mines – employing more people than any other sector and fueling 90 per cent of the country’s electricity generation – are vital to the national economy. But it’s a dangerous business, with miners operating in difficult conditions, often exacerbated by lack of investment following the collapse of the Communist regime in 1989. With its poor accident record the Halemba mine was no exception, though there had been nothing to compare with the tragedy that occurred on November 21 2006.

On that day, a kilometer below the surface, equipment was being recovered from Halemba’s 1,030 m (3,380 ft) level – closed the previous March after a dangerous concentration of methane gas was detected by a specialist, who was trapped there for five days after a minor explosion. But the equipment left behind was valuable and – despite the continuing presence of methane – that consisted of 23 miners ranging in age from 20 to 60, including inexperienced young hands supplied by private contractors.

It would prove to be a fatal assignment. A violent gas explosion ripped through the mine, almost certainly killing the unfortunate victims instantly. Six bodies were quickly recovered, but the remaining 17 were not found for two days, after rescue teams braved persistent methane to dig through collapsed tunnels.

Polish Prime Minister Jaroslaw Kaczynski declared a state of national mourning and arrived at the mine to commiserate with victims’ families in particular and the shocked mining community in general. In the manner of politicians everywhere after such happenings, he promised a thorough official enquiry but offered little hope that it would get to the root cause of the problem – poor safety standards in Poland’s mines – by suggesting that the likely culprit was that old scapegoat ‘natural forces’.

When: November 21 2006

Where: Ruda Siaska, Silesia, Poland

Death toll: 23 dead

You should know: Despite the Polish prime minister’s suggestion that the fatal explosion might be seen as an act of God, state prosecutors did not agree. After an exhaustive investigation, 27 individuals faced criminal charges in 2008, ranging from endangering the lives of miners resulting in death down to negligence and falsifying documents.

Anywhere in or around the Number 101 Petrochemical Plant in Jilin was definitely not the place to be on November 13 2005. For that was the day when explosions ripped through the state-owned China National Petroleum Corporation’s facility when a nitration unit malfunctioned. The sequence of powerful detonations lasted for an hour, shattering windows over a wide radius and starting fierce fires that would not be extinguished until the following morning. Six workers were killed with around 75 injured, many seriously.

The very real fear that there could be further blasts and possible chemical contamination caused the evacuation of 10,000 from the area around the plant. Suspicion that the disaster had caused severe pollution was eventually confirmed when it became apparent that a large quantity of carcinogenic benzene and nitrobenzene had leaked into the Songhua River. An 80 km (50 mi) toxic slick drifted down river, causing widespread disruption to drinking-water supplies as it went. Efforts were made to mitigate the disastrous leak – hydroelectric dams upriver opened their sluices in an attempt to dilute the dangerous level of benzene – but it was still more than 100 times greater than the national safety level.

China’s tenth-largest city was particularly hard hit. Harbin in adjacent Heilongjiang Province is located on the banks of the Songhua River downstream of Jilin, and public water supplies had to be cut off for more than three days as the pollution slick approached, causing great inconvenience to nearly four million inhabitants. With impressive efficiency, 100 new artesian wells were drilled to provide Harbin with uncontaminated ground water and ease the supply shortage, but the benzene continued to cause problems as it went on to enter the Amur River and passed through the Russian Far East en route for the Strait of Tartary and the Pacific Ocean.

When: November 13 2005

Where: Jilin City, Jilin Province, China

Death toll: Six

You should know: In typical knee-jerk fashion, the initial reaction of Jilin Petrochemicals’ management was to deny that pollutants had entered the Songhua River. Only when it became obvious that a serious benzene slick was heading for Harbin did they own up. The Chinese press was critical of the official response to the accident, forcing a senior government environmental minister to resign.