Vaping damages the lungs in the same way as gas poisoning, tests have revealed.

Experts have warned of a “public health crisis” after close examination of tissue samples found “direct” injuries from noxious chemicals.

For the first time, scientists reviewed lung biopsies from a disparate group of patients who had fallen ill after smoking e-cigarettes, two of whom died.

The team at the Mayo Clinic had been expecting to find lung damage as a result of fatty deposits from the vaping liquids.

Instead, they found more serious “acute” injuries of the type commonly seen in victims of a gas attack.

Published in the New England Journal of Medicine, the study comes amid rising concern about the safety of e-cigarettes across the world, and a week after Britain’s first death linked to vaping came to light.

Last month Donald Trump announced plans to ban flavoured e-cigarettes, over fears of their impact on young people.

Dame Sally Davies, England’s now-former Chief Medical Officer, also described vaping as a “ticking time bomb”.

Of the 17 patients from whom the samples were taken in the new study, only eight had previously smoked.

However, all exhibited foamy accumulations in the lungs indicating acute fibrinous pneumonitis, a type of scarring.