DENVER (KDVR) — The Colorado Department of Public Health and Environment suspects all McDonald's locations in the state "received ingredients from the same suppliers," and that all locations may be affected by an E. coli outbreak that has killed one and sickened 49 nationwide. The agency has also confirmed that the 26 people in Colorado who are confirmed to have gotten sick from an E. coli outbreak linked to the McDonald's Quarter Pounder lived in 9 counties: Arapahoe, Chaffee, El Paso, Gunnison, Larimer, Mesa, Routt, Teller and Weld counties. According to CDPHE, the person who died was from Mesa County. They were in their 80s and had other medical conditions. The CDC had previously reported that they were an "older adult." The outbreak, which has resulted in one death, was first reported by the Centers for Disease Control on Tuesday. Across 10 states a total of 49 people have gotten sick, more than half of them in Colorado. The first reported illness happened on Sept. 29, with the last reported illness on Oct. 11, according to the CDC. However, the CDC said it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak, and the true number of sick people related to the outbreak "is likely much higher than the number reported." CDC: Colorado death linked to McDonald’s E. coli outbreak McDonald's has pulled the Quarter Pounder from stores statewide in Colorado and four other states, as well as parts of eight states. According to a statement from the company, McDonald's believes the outbreak was caused by slivered onions that are not used on any other menu item. The CDC has not determined an exact item responsible for the outbreak and is investigating the onions and the beef patties used on the Quarter Pounders. CDPHE said it expects the number of people affected to increase as more cases are identified.