WASHINGTON - The Labor Department on Tuesday said it was increasing inspections to address potential health hazards to workers at plants that make microwave popcorn with butter flavorings that contain diacetyl.

The Occupational Safety and Health Administration's program will call for more inspections in places that make butter-flavored popcorn, a spokeswoman for the department said. Diacetyl is an artificial flavoring.

Last year, the National Institute for Occupational Safety and Health, or NIOSH, issued a report that found several employees at a microwave popcorn plant were diagnosed with a severe obstructive lung disease, the Labor Department said. NIOSH determined that inhaling the butter flavoring put workers at risk for the lung disease, the department said.

"We recognize that there are potential occupational health hazards associated with butter flavorings containing diacetyl. Under this program, OSHA will target inspection resources to those workplaces where we anticipate the highest employee exposures to these hazards," said Edwin Foulke Jr., the Labor Department's assistant secretary for occupational safety and health.