A major employer in deep southern Illinois is going to lay off 170 employees. Honeywell is idling a plant that converts uranium ore into uranium hexafluoride or UF6, a key ingredient in the enrichment of uranium that is used in nuclear power plants. The facility in Massac County is the only place in the United States where that work is done. Honeywell says a declining worldwide need for UF6 is causing the layoffs. According to a press release the plant will move to an idling phase and will be ready to restart if the UF6 market improves.