Walmart, the world’s largest retailer, will stop selling e-cigarettes amid “regulatory complexity” and “uncertainty” surrounding the industry, the company said in an internal memo Friday.”Given the growing federal, state and local regulatory complexity and uncertainty regarding e-cigarettes, we plan to discontinue the sale of electronic nicotine delivery products at all Walmart and Sam’s Club U.S. locations,” the company said. “We will complete our exit after selling through current inventory.”E-cigarettes are billed as a less harmful way for people to get their nicotine fix than traditional cigarettes. Yet a teen vaping “epidemic” and an outbreak of a deadly vaping-related illness has thrown the industry into turmoil. Health officials are investigating 530 cases of a mysterious lung disease that has killed eight people. Meantime, the Trump administration is readying a federal ban on flavored e-cigarettes, while cities and states are pursuing similar measures. Walmart raised the tobacco buying age to 21 earlier this year in response to what regulators are calling an “epidemic” of teen vaping. Preliminary federal survey data shows more than one-quarter of high school students say they use e-cigarettes. Lawmakers are blaming the surge in youth use of e-cigarettes on Juul, the market leader. Some are calling on the Food and Drug Administration to crack down on the largely unregulated industry. Impatient with the lack of action from the federal government, a number of retailers, states and cities have been taking their own steps to mitigate teen vaping.CBS, WarnerMedia and Viacom have all said they will stop running e-cigarette advertisements.