Vera Lawrence was a popular figure in the south Florida town of Miramar. The grandmother sang in the gospel choir, was an active member of the church community and always had a smile and a wave for any neighbour or stranger who passed her window. Her sudden death at the age of 53 stunned her friends and family. They had always known her as a fit and lively woman. Although she was overweight she had never suffered any serious health problems.

The shock was compounded with the release of the coroner's report. The apparently clean-living woman died of a lung embolism caused by silicone leaking into her bloodstream. The post-mortem recorded six litres of liquid silicone in her body, damage to every major organ and 36 puncture marks in her hips and buttocks.

Lawrence, a secretary for a respected Miami firm, paid with her life for pursuing the American dream of everlasting youth and beauty. She died at a bizarre illegal gathering known as a 'pumping party', the victim of a shady underground network of unlicensed cosmetic surgeons who tour suburban America injecting willing participants with huge quantities of industrial-grade silicone.

Details of her death emerged last week in the trial of two people accused of her murder. The court heard how in recent years she led a secret life in which she attended many 'pumping parties' and received numerous injections of silicone in her quest to acquire more curves.

The trial, which heard that at the party Lawrence's buttocks had been injected with more than two litres of silicone intended for furniture manufacture, has focused attention on the seedy but lucrative industry in outlawed cosmetic enhancements, in which unlicensed 'doctors' can earn up to $1 million a year.

'There are daily silicone parties all over south Florida,' said Enrique Torres, chief criminal investigator with the state's Department of Health. 'People from all walks of life gather for food, drink - and to have all kinds of things injected into them. They're like Tupperware parties.

'I have a department of six investigators working flat out but we're barely scratching the surface of the problem. Since the end of 1998 we've made 211 arrests relating to the illegal cosmetic industry in Florida, 88 of them people practising without licences, injecting silicone and other unlicensed products. But the guys doing this are like cockroaches: when the light is on them they scatter and disappear, but when the light goes off again they always scuttle back.'

Donnie Hendrix is a transsexual known as Viva. Her bloated face is testimony to the many silicone injections she has received. She was found guilty of culpable negligence and practising medicine without a licence, and faces up to six years in prison. Her co-defendant and lover, Mark Hawkins, faces up to 20 years in jail after being convicted of Lawrence's third-degree murder. Another transsexual, Cory Williams, in whose apartment Lawrence died, told the Fort Lauderdale court last week that Hendrix and Hawkins flew in from their South Carolina home and charged $1,000 (£620) just for appearing at the 'pumping party'. People then paid the pair, whom they believed to be licensed doctors, hundreds of dollars each for various 'treatments'.

Hendrix and Hawkins have a long history of illegal cosmetic practice, according to investigators. However the couple claimed that silicone from previous injections which they did not administer killed Lawrence, not the silicone injected into her on the night of her death in March 2001.

While the amount of silicone injected into Lawrence is considered extreme, cosmetic surgeons acknowledge that any quantity of the compound can cause problems. Bleeding and bruising are a mild side effect. Allergies, inflammatory reactions, silicone poisoning and the formation of granulomas - small, hard tumour-like growths - have all been reported in patients who suffered after silicone injections. Some patients have had limbs amputated.

'It's not a pretty picture. Liquid silicone, when it's injected, doesn't disappear,' said Dr James Wells, president of the American Society of Plastic Surgeons. 'The issue is whether it will stay where you put it, and generally the answer is no. Eventually it will begin to migrate south. It's called gravity. It's difficult to quantify how much of a problem this is nationwide but we do know it's being done and it's something that all of a sudden has come up again.'

While Florida has emerged as the centre of America's silicone subculture, pumping parties are being staged in homes, backstreet garages and hair salons all over the US. The American Society of Plastic Surgeons says victims have come forward from almost every state but areas in which pumping is most prevalent include Texas, Michigan, New York, Washington state and California.

'Although what happened to Mrs Lawrence was extreme, this is not as unusual as people might think,' said Dr Patrick Hudson, a plastic surgeon from Albuquerque, New Mexico. 'It's happening in a lot of places.'

The low-cost treatments are particularly popular with transsexuals seeking injections in their hips, buttocks, breasts, calves, arms or lips to give them a more feminine form. They claim they are forced to go underground because approved treatment is rarely covered by medical insurance policies. But educated, affluent Americans are also hiring the services of the unlicensed 'doctors'. One woman arrested last year after hosting a pumping party at her upmarket waterfront condominium in Aventura, Florida, told a local TV station: 'It's like the Avon lady coming over. It was treated so casually and everybody was so excited. They were all staring at each other, saying "How do I look?" And there they are, all bleeding and bruised, and they think they look beautiful.'

Torres says Miami is the silicone hotspot. 'It's the sun and fun capital of the south-east United States and attracts all the young and beautiful people. People see these models with bodies to die for and everyone aspires to that. There are the transvestites and transsexuals, the 'gothics' into extreme body sculpting, and what I would consider normal men and women who just want to slightly enhance their appearance.

'People allow this to be done and just don't think it's a medical procedure. But it's a ticking time-bomb in their bodies waiting to go off. I wouldn't even go to a licensed plastic surgeon. If God didn't give it to me, I don't want it.'

Dr Mariano Busso, a Miami-based cosmetic dermatologist, says it is not exclusively a low-income problem. 'I've seen people of high incomes who wanted a permanent fix because they get frustrated with the temporary nature of collagen. But it still amazes me how people can even think of being injected by someone not licensed, without sterile equip ment, in somewhere like a garage. It's scary how far it can go.'

Torres believes the criminal justice system must change before there can be any significant progress in the battle against unlicensed cosmetic practitioners. 'If you get caught with one ounce of heroin that's 25 years to life in prison. Yet you can buy an 18kg vat of silicone for $250, sell it for injections at $100 to $200 per millilitre, make a million bucks profit and end up with probation. The lure is the money. The criminals who are in this don't care for the people. They're just searching for the dollar.'

In his closing speech at the trial in Florida, prosecutor Howard Scheinberg told jurors that Lawrence paid the ultimate price for the insecurities that drove her to seek backstreet cosmetic treatments and that the accused couple were in the 'illicit business of pumping chemicals into human beings for a quick buck'.

'They were doing this barbaric thing for a lot of money. Vera Lawrence was nothing more than a human ATM.'

But before the jury retired to consider its verdict, one of the defendant's attorneys, Eric Schwartzreich, offered a different view. He said the cause of death was not that final injection; it was the endless pursuit of the perfect body which led her to accumulate silicone over many years.

'Do you know who killed Vera Lawrence?' he asked jurors. 'Unfortunately, Vera Lawrence killed Vera Lawrence.'