Out of 2,289 people who participated in a survey to assess the health impacts of jet fuel contamination in the Navy’s drinking water system last year, 87% reported symptoms, according to results released today by the Hawaii Department of Health and the U.S. Centers for Disease Control and Prevention’s Agency for Toxic Substances and Disease Registry (ATSDR).

Thirty-seven percent sought medical treatment and 17 people were hospitalized overnight.

Those surveyed reported a range of symptoms, such as burning in their eyes, nose and throat, nose bleeds, skin rashes and blisters, seizures, headaches, dizziness, coughing, wheezing, nausea, vomiting and diarrhea.

About 80% of those with symptoms reported improvement after switching to another source of water. However, 75% of participants who reported health effects said their symptoms lasted for 30 days or more.

The survey, conducted from Jan. 7 to Feb. 10, was voluntary and health officials say that it doesn’t capture the full scale of the health impacts from the jet fuel that contaminated the Navy’s drinking water system in November. About 93,000 residents in neighborhoods in and around Joint Base Pearl Harbor-Hickam are served by that system.

At least one household member from 1,389 of the 9,694 households that are estimated to have been affected participated in the survey, according to the results.

“This incident was unprecedented and impacted the lives and health of thousands of people,” said Kathleen Ho, DOH’s deputy director of environmental health, in a press release. “This survey helps to quantify their experiences. We are committed to continuing to work with ATSDR to search for answers on how the Navy’s contamination of its drinking water system impacts health and wellbeing.”

The drinking water contamination was a result of leaks at the Navy’s Red Hill fuel facility, which is now in the process of being shut down.