A federal report says artificial flavoring used in microwave popcorn may cause serious health problems for employees in popcorn factories. Tom Elsen is vice president for marketing at American Popcorn Company in Sioux City. He says health concerns aren’t an issue, as the plant was designed to keep the mixing facilities seperate from the microwave packaging area.The C-D-C report found no risk to consumers who prepare or who eat microwave popcorn. Elsen says all plant workers are required to wear certain protective devices, some more than others, depending on where they work.He says federal inspectors were at the plant a few months ago and were impressed with the safety measures in place.The federal report was conducted after several popcorn factory workers in Jasper, Missouri, contracted similar lung diseases.