In a surprise move, the Food and Drug Administration announced today that it plans to begin lowering nicotine levels in cigarettes to levels considered non-addictive, as it pegged tobacco use as "the leading cause of preventable disease and death in the United States."

From FDA Commissioner Scott Gottlieb: "The overwhelming amount of death and disease attributable to tobacco is caused by addiction to cigarettes — the only legal consumer product that, when used as intended, will kill half of all long-term users."

Why it matters: It's a huge public health move — and one that could serve as the death knell to the tobacco industry. Per Bloomberg, stock for the Altria Group, Philip Morris' parent company, had dropped as much as 19% this morning while British American Tobacco had plunged 11%.