While an estimated 99 percent or more of ethylene oxide was captured by pollution-control equipment at the plant, permits allowed some to be released directly into the air — an amount reported by the company to be more than 5,000 pounds in 2014. The emissions released through the “back vents” at the facility have been called “uncontrolled” by a federal agency because the emissions did not go through the pollution-control equipment. The company modified its plant in 2018 to route those emissions through its pollution control equipment.