For the past few years, there has been an increase in the popularity of vapes, especially among children and teenagers. Teenagers seem to think that choosing electric cigarettes is a healthier alternative. Scientists stress that this is not true, especially when we do not know exactly what we are smoking.

E-cigarettes were collected at Baxter College in Kidderminster as bbc.com reports. The decision was made to test them in a laboratory. It turned out that children who had smoked them may have inhaled twice the daily safe amount of lead and as much as nine times (!) the safe amount of nickel. Some of the electric cigarettes also contained chemicals.

It is worth noting that an elevated level of lead in child's organism can affect the central nervous system and brain development, the World Health Organisation warns.

The teachers, parents and laboratory researchers were terrified, when they learned that all vapes tested were illegal and had not undergone any testing before being sold in the UK.

David Lanson, co-founder of the Inter Scientific laboratory in Liverpool, said he had never seen such an amount of lead in the device he was testing.

"None of these should be on the market – they break all the rules on permitted levels of metal. They are the worst set of results I've ever seen," Lanson told BBC News.

In the vapes tested - designed in bright colours to look like highlighter pens - the amounts of metals found were:

• lead - 12 micrograms per gram - 2.4 times the established safe level of exposure,
• nickel - 9 micrograms (nine times exceeding the safe level),
• chromium - 6 micrograms (six times exceeding the safe level).

Laboratory tests also showed that the cigarettes contained compounds called carbonyls. These break down into chemicals such as formaldehyde and acetaldehyde, which were also detected in the smoke of the confiscated vapes.

The school head teacher Mat Carpenter was horrified by these findings. In order to reduce the possibility of vaping he installed sensors in the school toilets