MAQUOKETA, Iowa (AP) – City officials plan to ask residents to enroll in a program to monitor vapor contamination from a carcinogenic chemical that’s spread from a factory site in the eastern Iowa city of Maquoketa. The Telegraph Herald reported that the contamination stems from the operations of Clinton Machine Co., which built small engines in Maquoketa from 1950 into the 1990s. The factory used trichloroethene, commonly known as TCE, as a degreasing agent. Federal authorities have since determined that TCE is carcinogenic. Shelly Nellesen with the Iowa Natural Resources Department says the TCE in groundwater also creates the potential for indoor contamination.