The number of deaths in the United States caused by the use of e-cigarettes has risen to at least three.
A fourth death is being examined in this context, said Dana Miani Dillman of the US Health Authority (CDC).
"We are aware of three deaths and there is a case under investigation," Dillman said.


A total of 450 cases have been reported to health authorities to date, possibly caused by e-cigarettes, in more than 30 states.


The number of reports in the United States of vague lung diseases after smoking e-cigarettes has risen in recent weeks.
Symptoms ranged from shortness of breath to respiratory crises and chest pain to stomach and intestinal pain accompanied by vomiting and diarrhea.
Many of those infected were taking so-called liquid liquids that are vaporized with the cannabis-treated THC.
The Washington Post published a report Thursday on the effects of a substance that may be the cause of those diseases, and said it was found in different brands of drinks.
The article is available in vitamin E acetate, which experts found in many samples taken from cannabis products smoked by the infected.