Juul Labs Inc. has hired former Food and Drug Administration employees and is recruiting more researchers as it prepares for a crucial regulatory hurdle that will determine the future of the top U.S. e-cigarette maker.

The company and its peers must submit applications to the FDA by May 12 in order to continue selling their products. The deadline is a defining moment for the e-cigarette industry, which has been under fire following a surge in teen vaping and a lung-injury outbreak that sickened thousands and was later tied to THC.

For Juul, securing a swift clearance is critical. The company has seen its once-rich valuation drop since the broader vaping backlash began. Failing to win the FDA's blessing could shut it out of a market it has dominated.