Original sentence: In May 2006, Whirlpool announced plans to close the former Maytag headquarters office in Newton, as well as laundry manufacturing plants in Newton, Iowa, Herrin, Illinois and Searcy, Arkansas by 2007
Edited sentence: In May 2006, Whirlpool announced plans to close the former Maytag headquarters office in Newton, as well as laundry manufacturing plants in Newton, Iowa; Herrin, Illinois; and Searcy, Arkansas by 2007