Manufacturers of electronic cigarettes have told ITV's Tonight their industry is not regulated and there can be varying quality of products.
Long Xiaobing, CEO of an E-Cig company in Shenzhen, Southern China makes ten million electronic cigarettes a year.
He told Tonight: "Currently, lots of products in this market are not regulated and products vary in quality."
Another E-cigarette maker, Hua Ou, said: "There is no standard available to regulate them. So the market is in a bit of chaos now. Currently many E-cigarettes are made quite similar, with low quality. These are very serious problems."
Both manufacturers insist their own products are good quality, yet they are well placed to make judgements on the wider market.
Watch The Rise of the E-Cigarette: Tonight at 7.30pm on Thursday on ITV
More top news
The Canadian rapper surprised Sofia with a visit while she was in hospital.
The EU’s rejection of the Chequers plan is on nearly all the front pages.
Her visit to the centre in Houston came during a stop on her campaign tour of Texas.