A new study reveals low awareness among some Taiwanese electronic cigarette users they are vaping nicotine.

The online study, which received 1,608 valid samples from people aged 15 to 49, found that 5.5% are active vapers. The survey found 44.6% of them do not realize many vaping cartridges contain nicotine, according to the Health Promotion Administration (HPA).

According to an inspection conducted by the Food and Drug Administration, up to 90% of vaping products on the market were found to contain nicotine. For the nicotine-free ones, many still have methanol, ethanol, or other toxic substances, HPA said.