With a big victory for a Missouri factory worker, an Iowa lawsuit may not be far behind. The National Institute of Occupational Safety and Health had already linked vapors from popcorn flavoring to lung problems in people who worked with the substance for years. The Joplin, Missouri, worker who won a 20-million-dollar suit this week says he needs a double lung transplant, the damage was so severe. Nearly two years ago, a worker at Sioux City’s American Pop Corn was diagnosed with a lung ailment linked to diacetyl, a chemical in the butter flavoring used in Jolly Time brand microwave popcorn packed at the plant. The attorney who brought the successful suit on behalf of the Missouri worker says he also has cases pending in Iowa and Illinois…not against the popcorn plants, but the makers of the flavoring blamed by a host of workers for their health problems.