SPRINGFIELD — Sterigenics announced Wednesday it will reopen its Willowbrook plant after it installed new equipment which will reduce emissions of ethylene oxide.The commercial sterilization company uses ethylene oxide, or EtO, to sterilize medical equipment and other products. According to the National Cancer Institute, the colorless gas can cause cancer if inhaled.Under an agreement filed in the DuPage County Circuit Court, which is subject to court approval, Sterigenics will install additional emission capture and …