OKLAHOMA CITY (AP) - A bill that would prevent youth access to electronic cigarettes has been approved in the Senate. The Senate voted 26-15 on Wednesday for the bill that also limits the taxes that can be levied on the so-called ``e-cigarettes.'' An alternative to traditional cigarettes, e-cigarettes are battery-powered devices that heat a liquid nicotine solution and create vapor that users inhale. Under current law, there is no age restriction on the purchase of these products. The bill would prohibit anyone under 18 from purchasing any vapor or tobacco-derived products. The measure also imposes a .05-cent tax on such products and limits the maximum tax to 10 percent of that imposed on a pack of cigarettes.