WASHINGTON (Reuters) - A bipartisan group of U.S. senators on Friday urged federal regulators to immediately remove all pod and cartridge-based e-cigarettes from the market until it can be proven the products are safe.

In a letter to Ned Sharpless, acting commissioner of the U.S. Food and Drug Administration (FDA), Senators Dick Durbin, Lisa Murkowski, Jeff Merkley and Richard Blumenthal cited recent reports of 530 cases of vaping-related lung disease, as well as eight deaths, in asking for the ban.

The letter said cartridge or pod-based systems account for more than 70% of the overall e-cigarette market, and are favored by youth.

“Unfortunately, many cartridge-based systems are easily able to be opened and modified, exposing adolescents to the additional dangers associated with refillable, and modifiable, e-liquids,” the letter said.

Separately, Representative Raja Krishnamoorthi urged the FDA not to make an exemption for mint and menthol flavors in their pending guidelines that are expected to ban e-cigarette flavors.

“I say very strongly we are hearing that the vaping industry, the e-cigarette industry, is lobbying heavily for an exemption for mint- and menthol-flavored,” Krishnamoorthi, a Democrat, said in a conference call with journalists.

“Any such exception or exemption would be a tremendous mistake ... we respectfully request the FDA to resist,” he said.

Krishnamoorthi chairs the House of Representatives Oversight Subcommittee on Economic and Consumer Policy. He and Durbin this week formed a bipartisan caucus to combat the “epidemic” of youth vaping, along with Republican Representative Peter King and others.

The lawmakers have cited health experts who say flavors like mint from popular e-cigarette companies like Juul Labs

Inc have caused the surge in youth vaping.

Health and Human Services Secretary Alex Azar said last week that with President Donald Trump’s blessing, his department would move to ban all e-cigarette flavors other than tobacco in an effort to curb the use of e-cigarettes by youth.