In May 2011 Tulsa, Oklahoma health officials investigated E. coli O157 illnesses in 4 children. Three of the children attended Boston Avenue Methodist Church Child Care Program. The fourth child was a sibling of one of the confirmed day care attendees. Health department investigators collected stool specimens from all students, teachers and staff. All were negative for E. coli O157. The day care kitchen was inspected and no errors were noted. There were dirty diaper changing pads in the a classroom used by two of the ill children. Investigators reached no conclusions as to the source of the outbreak.