Video report by ITV News Reporter Rory Challands
Health officials in the US have told the public to stop vaping following the deaths of at least five people linked to the use of e-cigarettes.
The Centers for Disease Control and Prevention is investigating a "multi-state outbreak of severe pulmonary disease" associated with e-cigarette products.
It says five deaths have been confirmed in California, Illinois, Indiana, Minnesota, and Oregon.
And, on Saturday, public health officials in Los Angeles announced the first known death attributed to vaping.
Barbara Ferrer, Director of the LA County Department of Public Health, said: "Today we're issuing a warning to all residents about the use of these devices as potentially harmful to proper lung function.
"We join with the Centers for Disease Control to advise people to stop vaping now until further information about what is causing lung damage and death can be understood."
For millions of people around the world, vaping has been a way to stop smoking.
An electronic heating device creates a vapour from a nicotine solution but it's been considered a safer way of tackling nicotine addiction and far safer than smoking ordinary cigarettes, which are know to cause a host of cancers.
But now it's mired in its biggest health scare to date.
According to the Centers for Disease Control and Prevention, over 450 possible cases of lung illness associated with the use of e-cigarette products have been reported to CDC from 33 states and the US Virgin Islands.
It said: "While this investigation is ongoing, consider not using e-cigarette products.
"Regardless of the ongoing investigation, youth and young adults should not use e-cigarette products. Women who are pregnant should not use e-cigarette products.
"Adults who do not currently use tobacco products should not start using e-cigarette products."
One apparent victim was 18-year-old Piper Johnson from Chicago who survived her illness - but she's one of a rising number of vaping-linked incidents that required hospital treatment.
Ms Ferrer told a press conference: "Nationally, deaths and lung injuries related to the use of these devices are on the rise and this is the fourth known death reported in the United States within the last two weeks.
"To date there have been 12 reports of vaping associated pulmonary injury in Los Angeles County residents. The Los Angeles County Department of Public Health takes this threat seriously."
And, Dr Muntu Davis, LA County Health Officer, said patients were reporting some shortness of breath, coughing, sometimes a fever, which rapidly progresses to a severe lung disease.
"For all of these cases there is a history of vaping," he added.