Senate Democrats urged the Food and Drug Administration (FDA) to require stronger warning labels for e-cigarettes.

Sens. Barbara BoxerBarbara Levy BoxerThe ‘bang for the buck’ theory fueling Trump’s infrastructure plan Kamala Harris endorses Gavin Newsom for California governor Dems face hard choice for State of the Union response MORE (D-Calif.), Dick DurbinRichard (Dick) Joseph DurbinThis week: House GOP regroups after farm bill failure Overnight Health Care — Sponsored by PCMA — Trump hits federally funded clinics with new abortion restrictions Dem lawmaker spars with own party over prison reform MORE (D-Ill.), Richard Blumenthal (D-Conn.), Jack ReedJohn (Jack) Francis ReedDefense bill moves forward with lawmakers thinking about McCain Overnight Defense: Trump aide's comment mocking McCain sparks outrage | Haspel gets another 'no' vote | Pompeo floats North Korea aid for denuclearization Politicians, media explode over White House aide's comments MORE (D-R.I.), Sherrod Brown (D-Ohio) and Ed MarkeyEdward (Ed) John MarkeyHillicon Valley: Lawmakers target Chinese tech giants | Dems move to save top cyber post | Trump gets a new CIA chief | Ryan delays election security briefing | Twitter CEO meets lawmakers Twitter CEO meets with lawmakers to talk net neutrality, privacy Senate votes to save net neutrality rules MORE (D-Mass.) wrote to FDA Commissioner Margaret Hamburg Thursday asking her to finalize proposed rules to expand the agencies ability to regulate all nicotine products.

The senators wrote that because of a lack of federal regulations, e-cigarette companies are producing their own warning labels that fail to list all of the health threats. They said the pending FDA proposal warning also wouldn’t go far enough.

“In FDA's proposed 'deeming regulation,' the agency includes a warning label for e-cigarettes that does not adequately warn consumers on the known dangers of nicotine use. The proposed label reads 'WARNING: This product contains nicotine derived from tobacco. Nicotine is an addictive chemical,'” the letter stated. “We support requiring a label on nicotine's addictive properties, but we ask the FDA pursue requirements for more extensive warnings that address health risks that e-cigarettes pose.”

More lawmakers have grown concerned over e-cigarette use as nicotine poisoning incidents rise.

The Democratic senators have also introduced the Protecting Children from Electronic Cigarette Advertising Act, which would ban marketing e-cigarettes to minors.