The CDC is investigating an E. coli outbreak that has sickened 49 people in 10 states, including one person who has died.

A total of 49 people have been sickened in 10 states in the Midwest and Western U.S., resulting in one death and 10 hospitalizations, according to the CDC

The fast food chain has pulled some of the burger’s ingredients across multiple states as officials try to pin down what specific ingredient is contaminated.