They may look like travel shampoo bottles and smell like bubblegum, but after a few hundred puffs, some disposable, electronic cigarettes and vape pods release higher amounts of toxic metals than older e-cigarettes and traditional cigarettes, according to a study from the University of California, Davis. For example, one of the disposable e-cigarettes studied released more lead during a day’s use than nearly 20 packs of traditional cigarettes.