From Bangkok and Pattaya to holiday resorts across Europe, the gas-filled balloons have been the hottest thing on the party scene this summer, being openly sold in their millions and providing a new line in seasonal work for opportunist street vendors.

"Every few steps you take there's someone hassling you to buy one," says Rebecca, an 18-year-old trainee kindergarten teacher. "It costs €2 [HK$20] for a balloon, but the prices go up when you go into the busier areas.

"The main strip in Ayia Napa is full of sellers and most of … them are teenagers around our age who've come out here to work for the summer and get 40 cents for every balloon they sell. They sell them in the nightclubs, too, and some bars offer a cocktail, a shot and laughing gas all in for €5."

One of Rebecca's friends, Claire, 19, describes the sensation: "It only lasts for about 10 seconds but it makes you feel like you're in your own world. Sometimes I felt a bit out of my own control and like my whole body was shaking and I couldn't stand up properly, but it's such a good feeling."

In Ayia Napa and hundreds of resorts like it, the balloons are openly marketed because there is nothing illegal involved in the sale of laughing gas. Nitrous oxide, delivered in steel capsules, has for decades been widely used in the catering industry, for the production of whipped cream. Its sudden popularity has seen a surge in demand from the factory in Taiwan where most of the world's capsules - known as cream chargers or, in Australia, nangs - are produced.

The cream chargers are single-use, finger-length canisters containing eight grams of highly pressurised nitrous oxide. To turn them into the means for achieving a legal high, the canisters are emptied into balloons using a whipped cream dispenser or a small widget called a cracker.

Although laughing-gas balloons have been used as a recreational drug for decades, their popularity has exploded this summer - largely, it seems, because the canisters containing the gas and the pumps used to extract it and inflate the balloons have become cheaper and more widely available.

The craze for nitrous oxide, nicknamed "hippy crack", has grown to the extent that 470,000 people aged 16 to 59 have tried it in the past year in Britain alone, according to Home Office figures. That number includes 7.6 per cent of 16 to 24 year olds, compared with the 4.2 per cent who have tried cocaine and 3.9 per cent who have taken ecstasy.

The sight of burst balloons and spent nitrous oxide cartridges has become a nuisance in areas of east London, where the craze has been particularly virulent, and, observers say, the inhaling of laughing gas has become as widespread as glue sniffing was in the 1980s.

On one Saturday night in July alone, more than 1,200 discarded chargers were picked up outside pubs and clubs in Shoreditch, east London, by council workers.

Celebrity users are said to have included Britain's Prince Harry, who indulged at a fancy dress party in 2010, and American actress Demi Moore, who was reportedly hospitalised after a nitrous oxide binge in her Los Angeles home that followed her split from husband Ashton Kutcher, in 2012.

The spread of the craze has triggered health concerns. It has been blamed for 17 deaths in Britain between 2006 and 2012, according to coroners' court data, and the Local Government Association (LGA), which represents 400 councils across England and Wales, has issued a health warning about the dangers of inhaling the gas.

The notice says regular intake of nitrous oxide can lead to oxygen deprivation, which can result in loss of blood pressure, fainting and even heart attacks. Prolonged exposure can cause anaemia, bone marrow suppression and poisoning of the central nervous system, says the LGA, adding that it is particularly concerned at internet clips posted on social networking sites showing children inhaling the gas.

A court in France earlier this year ruled that a 21-year-old British chef who had been working in the country, Jordan Guise, died of asphyxiation after inhaling nitrous oxide. Two years ago, 17-year-old Joseph Benett died after inhaling butane and pentane gas from a canister he believed contained nitrous oxide.

However, deaths have been relatively few considering the scale of the craze and DrugScience, a British-based information service that sets out to debunk popular myths about drug use, describes it as "one of the least risky drugs".

Inhaling nitrous oxide using unsafe methods for extended periods of time can cause brain damage and death, DrugScience concedes, but, it concludes: "These risks are unlikely with the common balloon method."

In a strikingly graphic description of the gas' physical effect, DrugScience says, "When someone inhales nitrous oxide, the gas rapidly dissolves into the bloodstream, and hits the brain within seconds. Effects vary between people and are rarely quite the same twice, but a rush of dizziness and euphoria is normal, and people often burst out laughing. Sound is oddly distorted, voices and music often turning into a throbbing roar like a helicopter.

"Hallucinations are possible, from simple moving bright dots to complete detailed dreamscapes, although most users do not experience complex hallucinations." The experience, it says, "ends swiftly with the peak lasting a few seconds and the user back to normal within two minutes".

Thousands of miles from the epicentre of the debate over the craze for laughing gas, Hank Chen is bemused and mildly amused at what he considers an unnecessary fuss, as his factory, in Taiwan, struggles to keep pace with the demand.

Chen is a sales director at Mosa, the world's biggest producer of nitrous oxide cream chargers and the name that is most commonly seen on empty cartons littering the streets of London and Mediterranean party resorts.

Mosa, which also makes airbag inflators and canisters for soda syphons, has been manufacturing the chargers for 10 years and now produces some 500,000 nitrous oxide canisters a day for distribution worldwide.

Since 2007, production has taken place on a modern 180,000 square metre site in Yunlin county, in Taiwan's central agricultural belt, where the company employs 415 workers, including more than 100 Vietnamese migrants who live in dormitories on site and earn basic salaries equivalent to about HK$4,650 a month. Workers recruited from nearby farming villages travel by motorbike and bicycle to work at the factory and get basic monthly salaries equivalent to about HK$6,500 - good money for an area made up mostly of pig farms, rice paddies and wheat fields.

The canisters are produced in a 30,000 square metre unit where workers stand in rows at computerised stations that fill the chargers with nitrous oxide. Outside, 200 yards away, stand 30-feet high containers of nitrogen oxide and carbon dioxide, used for soda syphon canisters.

Chen - whose corporate customers include Starbucks - says, "I have heard of this craze overseas and I've heard of young people taking nitrous oxide in nightclubs, but I don't think it is a big issue. I don't think it will cause a serious problem in society. Up to now there is no evidence or research showing it does any harm."

About 10 years ago, he says, concerns were raised in the United States Congress about a similar trend in America of young people misusing his product for legal highs and a ban was considered.

"In the end, though, they decided it was not something that would damage young people, so they just left it," says Chen, who thinks the current craze will soon pass.

Despite the rising popularity of the gas in Britain, Chen says, Mosa does not know where its product ends up. "We just sell [the gas canisters] to our distributors. We don't sell directly to end users. We really don't know where it goes. If there is more demand, our distributors just order more."

However, Chen says, production is already at full capacity and he expects Mosa to double production by adding another 30,000 square metre plant to produce the cream chargers within five to 10 years.

Asked if he would discourage young people from inhaling the gas, Chen replies, "We cannot control this craze so it is very difficult for us to comment. But if it really was damaging - if it was causing nerve damage to people or something - we would take action. We have a responsibility to society."

As summer burns itself out on the beaches of the Mediterranean, young street vendors are continuing to do a brisk trade in balloons.

"It's so addictive," says 17-year-old Fiona, giggling uncontrollably as she comes down from yet another nitrous oxide high. "I've spent about €60 on the balloons tonight and I've loved it."

Her parents would probably be mortified but Fiona is clearly enjoying herself too much to care. Her peels of helpless laughter are an unofficial soundtrack to the summer of 2014 - and there is no sign of the bubble bursting on this craze any time soon.

Red Door News Hong Kong

Dead poets society

Youngsters getting high on laughing gas might think they're at the vanguard of a bold new trend but Samuel Taylor Coleridge and his literary friends beat them to it by more than two centuries.

The celebrated Romantic poet, author of The Rime of the Ancient Mariner, experimented with the gas at the end of the 18th century with a circle of friends led by the brilliant young chemist and inventor Humphry Davy.

Describing his first encounter with laughing gas, Coleridge wrote: "I felt a highly pleasurable sensation of warmth over my whole frame, resembling that which I remember once to have experienced after returning from a walk in the snow into a warm room. The only motion which I felt inclined to make was that of laughing at those who were looking at me."

Another in Coleridge's circle, Robert Southey, who went on to become a British poet laureate, described "a sensation perfectly new and delightful" after trying laughing gas, and declared, "The atmosphere of the highest of all possible heavens must be composed of this gas."

In the absence of cream chargers, the young poets used more primitive methods to dispense and inhale nitrous oxide, usually by sucking it in from a bag. Davy was so taken with the sensation he constructed an airtight breathing box that he sat in for hours inhaling huge quantities of the gas, enjoying prolonged hallucinations and almost killing himself on more than one occasion.

As for Coleridge, he survived his experiments with laughing gas but became addicted to opium, the "sweet poison" he credited with opening up his mind but which contributed to his death, aged 61, from a heart attack and a lung disorder.