A big chemical accident at Seveso in Italy releases a cloud of poisonous gases (dioxins). No people are killed but the area becomes uninhabitable.

The ink jet printer is developed by IBM.

The last recorded case of smallpox occurring naturally in the wild is seen in Somalia.

In America the first company is set up to develop products through genetic engineering.

A baby mammoth which has been frozen in ice for 40 000 years is discovered in the Soviet Union.

In New York City two homosexual men are diagnosed with a rare cancer. They are probably the first victims of AIDS, although the disease is not officially recognised until 1981.

The Apple II personal computer is launched.

Alison Paul and D Southgate work out the amount of fibre in various foods, preparing the ground for a possible link between fibre and cancer of the colon.

CFCs are banned in America as a result of evidence showing that they damage the ozone layer.

Louise Brown, the first 'test-tube baby' is born. She is the result of in vitro fertilisation, where her parents gametes joined outside her mother's body. The developing embryo was then returned to her mother's uterus to develop normally.

In England, Walter Bodmer suggests a way of using DNA technology to find gene markers to show up specific genetic diseases and their carriers.

The nuclear reactor at Three Mile in America island loses its water coolant and suffers a partial meltdown, but no-one is injured.

Swiss physicist Heinrich Rohrer and his German colleague Gerd Binnig invent the scanning tunnelling microscope which is sensitive enough to provide images of individual atoms at a surface.

Louise Clarke and John Carbon clone a gene involved in cell division in yeast cells.

Several teams of physics researchers announce that the neutrino may have a mass.

Chinese scientists successfully clone a fish - a golden carp.

Aspartame, an artificial sweetener, is introduced in the United States.

AIDS - Acquired Immune Deficiency Syndrome - is recognised for the first time after it was first noticed in the homosexual communities of the USA.

IBM introduce a personal computer using DOS - Disk Operating System - which will become the standard for almost the whole computer industry.

Solar One, the world's largest solar-power generating station goes into operation generating up to 10 megawatts.

The first successful heart and lung transplant is carried out.

The USA space shuttle Colombia is launched as fully operational for the first time.

The Mary Rose, a Tudor warship, is lifted out of the water in Portsmouth, England. The ship turns out to be full of bits and pieces from ordinary Tudor life.

A gene for rat growth hormone is successfully transferred into mice, which grow up to twice their normal size because of the extra growth hormones they are producing.

The first human insulin made by bacteria as a result of genetic engineering is marketed.

Compact-disc (CD) players are introduced for the first time.

American physicist William Fowler and his Indian-born colleague Subrahmanyan Chandrasekhar win the Nobel prize for work on the ageing and ultimate collapse of stars.

The second flight of the space shuttle Challenger carries Sally Ride, the first American woman into space, as one of the crew. The third Challenger flight carries Guion Bluford Jr, the first black American in space.

In America, James F Gusella finds a genetic marker for Huntington's disease.

In America, Charles Sibley and Jon Ahlquist use DNA to show that humans and chimpanzees are more closely related to each other than either of them are to any of the other great apes.

J C Bhattacharyya and his team in Bangalore, India discover an extra two rings of Saturn.

West German scientists synthesise 3 atoms of element 108.

For the first time smoking is listed as a risk factor for strokes.

Apple computers brings the mouse and pull down menus into the home computer market.

Alec Jeffreys of Leicester University in England develops the technique of genetic fingerprinting which can be used to establish family relationships and to identify criminals.

Sheep embryos are successfully cloned.

GIFT (Gamete IntraFallopian Transfer) is developed, a simpler procedure than full in vitro fertilisation.

The first cross-species transplant is done. Baby Faye is born with a malformed heart which is replaced with the heart of a baboon. She lives for 20 days.

Scientists find a gene marker for cystic fibrosis on chromosome number 7.

Human growth hormone produced by genetically engineered bacteria is made available for treatment of children with growth problems.

In England Harry Kroto, Robert Curl and Richard Smalley discover a new form of carbon known as buckminsterfullerene or 'bucky balls'.

The AT&T Bell laboratories sends the equivalent of 300 000 telephone conversations (simultaneously) or 200 television channels at once over a single optical fibre.

On January 28 the space shuttle Challenger blows apart 73 seconds after lift off, killing all of the astronauts and the first civilian to be carried into space, a teacher called Christ McAuliffe. She was taking experiments designed by children into space.

The first monoclonal antibodies are used to help in organ transplants.

At 1:23am local time on April 26, a nuclear reactor at Chernobyl in the USSR explodes. This leads to a massive leak of radioactive material that kills many people, affects soil as far away as the UK and means all families within a 30km radius eventually have to be evacuated.

Genetically engineered plants are grown outside in field trials for the first time in the USA. The plants are genetically altered tobacco.

The supreme Court of America rejects the idea that the biblical creation story should be given equal teaching time to evolution in American schools.

A fossilised dinosaur egg is discovered which X-rays show contains the oldest known embryo - 150 million years old.

A team lead by Ching-Wu Chu at the University of Houston makes a material which is superconducting at the temperature of liquid nitrogen - minus 196°C.

Herbert Naarmann and N Theophilou from BASF in Germany develop a form of plastic polymer that is in some ways a better conductor of electricity than copper is.

A crime suspect is convicted on the evidence of genetic fingerprinting in the UK

Working with a team of American and Finnish scientists, David Page and his colleagues find a single gene on the Y chromosome which seems to control the sequence of events which leads to an embryo developing testes instead of ovaries - in other words, a gene for maleness.

The first successful transplant of a liver and small intestine is carried out.

Chemists estimate that there are 10 million known chemical compounds and that 400 000 more are synthesised or discovered each year.

British scientists report that the average wave height in the sea off Land's End in Cornwall has increased from 2.3m to 2.7 m since 1962, and speculate that this might be an effect of global warming and climate change.

A patent is granted to cover a genetically engineered mouse.

The first commercial supplier of dial-up access to the Internet comes on-line.

Wolfgang Krätschmer from Germany and Lowell Lamb from America together with their team of coworkers discover that buckminsterfullerene can be isolated from soot by dissolving it in benzene.

The Human Genome project is set up, a collaboration between scientists from around 16 countries to work out the whole of the human genetic code.

Human gene therapy is attempted successfully for the first time. A modified virus is used to carry the healthy gene for a particular enzyme into the cells of a woman with a very weak immune system. It gives her a normally functioning system, but only temporarily - the treatment has to be repeated regularly.

The World Wide Web (WWW) is invented by Tim Berners Lee working with Robert Cailliau at CERN in Switzerland.

Tracey, the first transgenic sheep, is born. She has human genes which enable her to produce human protein in her milk. This protein is extracted and can be used to help relieve the symptoms of people suffering from cystic fibrosis and emphysema.

In Japan Sumio Iijima of NEC Corporation discovers carbon nanotubes, related to buckminsterfullerene and known as "bucky tubes". They may replace the silicon chip in the future.

The risk of carbon dioxide buildup and global warming is recognised during the Earth Summit in Rio de Janeiro. Countries from all over the world meet up with the objective of stabilising green house gas concentrations at a level that will prevent interference with the world climate. It results in emissions limits being accepted - but with a very long time before these limits have to be met.

The first 'xenotransplant' from one type of animal to another involving genetically engineered tissue (liver) is carried out successfully.

Flat screen TV sets are demonstrated for the first time.

The bacterium Haemophilus influenzae is the first living organism in the world to have its entire genome sequenced.

Ian Wilmut clones several lambs from the cells of a 9 day old embryo lamb.

Dolly the sheep is born. She has been produced by Ian Wilmut and his team at the Roslin Institute near Edinburgh. To produce her, DNA from cells cloned from an udder cell of an adult sheep has been inserted into a sheep egg. This egg has then been implanted into the uterus of a completely different sheep.

Polly the sheep born later in the year is the first genetically engineered sheep to be cloned.

At the University of Hawaii, Teruhiko Wakayama and Ryuzo Yanagimachi use freeze dried mouse sperm, which is technically dead, to produce normal living mice offspring. The sperm is rehydrated before use. It will make the process of artificial insemination very much easier if the same process works for larger domestic animals.

Dolly the sheep gives birth to her own lamb, showing that she is capable of reproducing normally.

James Thomson at Wisconsin and John Gearhart in Baltimore both developed a technique for culturing embryonic stem cells which have enormous potential for forming new organs for transplants without problems of rejection.

The building of a new international space station to replace Mir is begun. It is a major cooperative venture between the USA and Russia, with 14 other countries including the UK contributing funds and expertise.

Healthy cloned goats are produced for the first time. Like the earlier sheep, they contain an engineered human gene so that they can make an anti-clotting factor in their milk.

A US firm buys the technology used to clone Dolly in a bid to clone cells from patients to produce new organs for transplanting.

World Wide Web estimated to cover 1 billion pages.

Cloned pigs are born for the first time in work done by Alan Coleman and his team at PPL Therapeutics in Scotland.