Anti-smoking groups are not happy with the Food and Drug Administration (FDA) regarding a decision to delay the review of e-cigarettes, and the groups are suing the organization. 

Time reports that a lawsuit was filed on Tuesday, March 27. It argues that when pushing back the deadline for manufacturers of e-cigarettes to submit products for review, the FDA did not follow requirements. As a result, the groups say, children’s health is at risk. 

According to the lawsuit, the American Heart Association, the American Academy of Pediatrics, the Campaign for Tobacco-Free Kids and others claim “the FDA offered no meaningful justification for ripping a hole in the statutory framework.”

An FDA spokesperson declined Time’s request for comment. 

E-cigarettes have risen in popularity in recent years. The battery-powered alternative to traditional cigarettes works similarly to a fog machine, NBC reports: it heats a liquid, which becomes an inhalable vapor. 

From the beginning, health advocates have expressed concern over the devices. A study from the Bloomberg School of Public Health at Johns Hopkins University found that the vapor from e-cigarettes can release toxic metals.

Additionally, researchers from a Keck School of Medicine of USC study state that teenagers who use e-cigarettes are six times more likely to smoke later in life in comparison to teens who never use the devices. 

"It's slick, it's high tech, it looks like a thumb drive on a computer, which means you can hide it easily," Vince Willmore of the non-profit group Campaign for Tobacco-Free Kids told CBS News. "And it gives a very strong hit of nicotine. So, this is about an ideal tobacco product to get kids hooked."

Time reports that in 2016, the FDA “gained authority to regulate e-cigarettes.” With rules put in place by the Obama administration, e-cigarette companies were to submit their products to be reviewed by August that year. However, in 2017, FDA Commissioner Scott Gottlieb announced that deadline would be moved to 2022 because the FDA and the e-cigarette industry needed more time.

Earlier in March, Gottlieb told the Associated Press that the FDA planned to do something about "products that are being marketed in kid-appealing ways." However, he also stated he did not want to do away with devices that could potentially help adults quit smoking. 

“What we don’t want to do is snuff out the potential for that innovation before we really have the opportunity to properly evaluate it,” he told the Associated Press. 

Although there has been minimal research about their long-term effects, e-cigarettes have become a $4 billion industry.