Iceberg lettuce that had been prepared and served to patrons of the Wendy's Restaurant, in Ogden, Utah, and to attendees of a catered teachers' conference at a junior high school (CORE academy) was implicated in an outbreak of E. coli O121:H19 infections. This is a rare strain of E. coli. Three people developed kidney failure. Lettuce was the only food that all of the sickened people had eaten. The lettuce was not available for testing after the outbreak was recognized.