As the use of electronic cigarettes increases among youths, 40 attorneys generals are arguing that the devices should fall under the Tobacco Control Act, which restricts the marketing and sale of tobacco products.

The attorneys general issued a joint letter Tuesday to U.S. Food and Drug Administration Commissioner Margaret Hamburg, urging the federal agency to meet the FDA’s own Oct. 31 deadline for issuing proposed regulations of e-cigarettes.

“We ask the FDA to move quickly to ensure that all tobacco products are tested and regulated to ensure that companies do not continue to sell or advertise to our nation’s youth,” the letter said.

An FDA spokeswoman said the agency still aims to issue proposed regulations by October but may or not hit that deadline.

E-cigarettes are battery-operated devices that heat liquid nicotine into a vapor that the user inhales. E-cigarettes are marketed in prime time TV advertising spots, online and via cartoon characters and come in kid-appealing flavors such as gummy bear, bubble gum and chocolate.

There are no federal laws restricting the sale or marketing of e-cigarettes to minors and many states' laws don’t cover them, either.

The National Youth Tobacco Survey conducted by the Centers for Disease Control and Prevention show e-cigarette use among high school students doubled in 2012 over 2011. In all, 1.8 million high school and middle school students report having used an e-cigarette in the past year, the survey found.

The letter to the FDA was signed by attorneys generals in 37 states and three U.S. territories.