Supreme Court justices questioned an FDA crackdown that involved rejections on sales of more than a million nicotine products created to taste like fruit and candy.

The Supreme Court on Monday pressed the Food and Drug Administration on whether it followed the law in its effort to keep flavored e-cigarettes off shelves, weighing a lawsuit from a multibillion-dollar industry that has come under scrutiny because its products are popular with school-aged children.

With e-cigarettes and flavored vapes booming in popularity, the U.S. Supreme Court on Monday will examine whether the Food and Drug Administration unlawfully blocked the marketing and sale of more than a million new sweet and candy-flavored nicotine products in recent years.