Sanofi has begun the process of laying off workers at its Kansas City manufacturing plant and expects to completely close the plant by August 2016, four years later than originally expected.

The company, formerly Sanofi-Aventis, plans to cut 112 employees by July 1 with the other layoffs scheduled for Dec. 31, 2012, June 30, 2013, and Dec. 31, 2014, before finally closing.

In all, 337 employees will lose their jobs.

The company in August 2009 announced plans for a phased closure of the plant, citing a decline in the volume of products manufactured there. The original timetable called for the plant at 10236 Marion Park Drive. to be closed by the middle of this year. Last week, it notified the state of Missouri and city officials about the new schedule.

The 36-year-old plant manufactures solid-dose oral medications, including Allegra. It was the last plant operated by Marion Laboratories, the company established by Ewing M. Kauffman. Sanofi has owned it since 2000.

Company spokesman Jack Cox said Monday that affected employees have been offered packages that include severance pay, health benefits and outplacement services.