Four people are dead after an outbreak of Legionnaires disease linked to a North Carolina state fair.

The outbreak is believed to be connected with the North Carolina Mountain State Fair that ran from Sept. 6 to Sept. 15. in Fletcher, North Carolina. It has specifically been linked to a hot tub display set up in the Davis Event Center during the second half of the fair.

Initial tests showed some of the hot tubs did not contain any sign of Legionella bacteria. However, state health officials noted samples tested were collected nearly three weeks after the fair.

“Finding Legionella in one water sample is an important piece of the puzzle, but it does not tell us how so many people were exposed at this event,” state epidemiologist Dr. Zack Moore said in a press release from the North Carolina Health Department.

As of Monday, 94 people have been hospitalized as a result of the outbreak. Over 130 fair attendees have been diagnosed with Legionnaires since the fair while four have died from it. Another eight attendees reportedly have a milder version of the illness called Pontiac fever.

According to the CDC, Legionnaires is a type of pneumonia, or lung infection, caused by Legionella bacteria. It typically occurs when people drink water or breathe mist that is laced with the bacteria. Symptoms include headache, muscle aches, fevers, coughing and chest pains.

Pontiac fever is a milder version of Legionnaires that causes fever, chills, headaches, and muscle aches. However, it does not attack the lungs the way Legionnaires does.

State health officials are encouraging anyone showing early symptoms of Legionnaires to visit their local doctor in an effort to keep it from spreading and treat it faster.