Electronic cigarettes should be banned, recommend researchers,till the safety concerns are in place.
Electronic nicotine delivery systems or ENDS are not tobacco products, but are designed to look and feel like regular cigarettes.
They are aimed at smokers for use in places where cigarette smoking is not permitted, as they don't produce smoke.
The e-cigarettes were studied for accuracy and clarity of labelling; and the quality of instruction leaflets and associated printed material either supplied with the product or available on the manufacturer's website.
The basic design of all the products was similar, but the design features varied considerably, the evaluation showed.
Fluid containing nicotine readily leaked out of most cartridges, and it was difficult to put together or take apart the devices without getting nicotine over the user's hands.
Cartridge labelling was very poor, with most replacement packs lacking any indication of cartridge content, expiry date, or health warnings.
Cartridges claiming to have no nicotine content looked identical to those claiming to have high nicotine content and they were indistinguishable once removed from their packs and wrappers.
Safety features did not always work correctly and print and internet material often contained information or made claims for which there is currently no scientific evidence, said the authors.
"Our observations provide evidence that regulators should consider removing ENDS from the market until design features, quality control, labelling, disposal and safety issues have been adequately addressed," concluded the authors.
The findings were published in the Tobacco Control.