A fondness for microwave buttered popcorn may have led a 53-year-old Colorado man to develop a serious lung condition that until now has been found only in people working in popcorn plants. Lung specialists and even a top industry official say the case, the first of its kind, raises serious concerns about the safety of microwave butter-flavored popcorn. “We’ve all been working on the workplace safety side of this, but the potential for consumer exposure is very concerning,” said John B. Hallagan, general counsel for the Flavor and Extract Manufacturers Association of the United States, a trade association of companies...