An E. coli outbreak linked to McDonald's Quarter Pounders has led to one death, hospitalizations and dozens of illnesses in 10 states, the Centers for Disease Control and Prevention announced Tuesday.

At least 49 people have been sickened as of Tuesday, Oct. 22, apparently after eating the quarter-pounders. A map provided by the CDC shows most of the cases are in Utah, Colorado, Wyoming and Nebraska. There have also been reports in Oregon, Montana, Kansas, Missouri, Iowa and Wisconsin. At least 26 people were sickened in Colorado alone.

McDonald’s said it was taking “swift and decisive action” to control the outbreak that has sickened dozens of people, mainly in Colorado and Nebraska.