A proposal introduced on Tuesday by the Food and Drug Administration could result in warning labels and child-resistant packaging on bottles of liquid nicotine used in electronic cigarettes.

It is the first regulatory action on e-cigarettes the US agency has announced since proposing regulations in April 2014 that would allow it to assume oversight of the $3.5 billion industry. The FDA is expected to complete those rules within the next two months. As part of the rules, it is also expected to restrict sales of battery-powered devices to anyone under 18 years old and require manufacturers to submit their products for federal approval.

Federal and state lawmakers have urged the FDA this year to accelerate its push to regulate e-cigarettes. They have expressed alarm about nicotine poisonings and a report by the federal Centers for Disease Control and Prevention in April that e-cigarette use among teenagers tripled between 2013 and 2014.