Candy-Marie Ward was 29 when she suffered cardiac arrest and died on 31 December last year. She had been inhaling butane, the key ingredient of cigarette lighters, for several years and had become addicted to it.

Her postmortem report gave the cause of death as cardiorespiratory arrest induced by inhaling a volatile substance.

Ward's mother, Sharon Stevens, told local newspapers that her daughter, who lived in Wandsworth, south London, had been allowed to buy butane on credit from local shops. Ward had been at home with her partner and 14-year-old son when she inhaled two bottles of butane and collapsed.

Stevens has called for stricter controls to be introduced to limit the sales of lighter fluid.

The case of Ward was not an isolated one, however. Last week campaigners released a report revealing that butane was now the leading "legal high" killer in the UK and is claiming the lives of more than 40 people a year. These campaign groups are not only pressing for stricter laws to govern butane sales, they want the government to restore funding to the surveillance units that had been monitoring volatile substance abuse, but were recently forced to abandon their work due to cuts in their funding.

"We need to keep a very close eye on this problem, but we cannot do this if we cannot monitor fluctuations in yearly figures," said Stephen Ream, director of Re-Solv, the charity which produced the report and which was set up to help combat glue and aerosol abuse.

"New types of volatile substance could suddenly appear, for example, and without proper monitoring we would miss the impact they were having on young people – until it was far too late," said Ream.

This point was supported by analytical toxicologist John Ramsey, of St George's University, London. In the past, cases of volatile substances were under-reported, until his unit began monitoring the problem in the 1980s. "In the early 1990s, we showed deaths involving mostly youngsters had reached a peak of more than 150 a year," he said.

Following the release of these figures, the Department of Health launched campaigns to help parents to pinpoint adolescents at risk. Adverts were put in women's magazines and leaflets distributed in doctors' surgeries. The campaign worked well and deaths from volatile substance abuse fell to about 50 a few years later.

However, the numbers of deaths from volatile substance abuse – of which butane sniffing forms the vast majority – have remained static since then, Ramsey has found, although there has been a significant change in the pattern of deaths.

The problem now affects far fewer teenagers and has instead become an issue for young adults. In addition, there has been a change in the sex ratio of volatile substance abusers. When the problem was confined to adolescents, boys formed the vast majority of cases. But now there are a growing number of women who have become affected by the problem – an example being provided by the case of Ward.

"The problem with a substance like butane is that it gives you a quick hit that leaves you wiped out for a couple of minutes," said Ream.

"Then you recover in another 10 or 15 minutes. In addition, it is very, very cheap. It's just lighter fuel, after all. The trouble is that every so often it will simply kill you."

As a result, groups like Re-Solv are pressing supermarkets to limit sales of butane to single purchases. "The trouble is that it is very difficult to control sales at little corner stores," said Ream. "We really need better government controls – and the restoration of funds so we can keep monitoring this problem."