US health investigators are casting a wide net to understand what is sickening hundreds of vapers across the country, after the sixth person has died.

They have not ruled out any product on the market, even as vaping industry officials highlight the potential role of illegal cannabis products.

Dr Dana Meaney-Delman is leading the US Centers for Disease Control and Prevention’s investigation into the culprit behind at least five confirmed deaths and 450 reported cases of lung illness linked with use of the devices.

The agency is recommending that people refrain from using any electronic cigarette or vaping device until there is more conclusive evidence of a cause, she said in an interview.