Other chemical engineers are employed at refineries and industrial plants, where the engineer is expected to respond in case of an emergency at the plant, which could mean exceeding a 40-hour workweek. Some chemical engineers commonly work 45 to 50 hours a week in a plant or refinery environment. Some chemical engineering jobs call for extensive travel to and from worksites within the U.S and abroad, which can also push the total working hours above full time.