Two people died and several others were treated Wednesday after they were exposed to an unknown substance at a senior residential community in Syracuse, New York, authorities said.

Syracuse fire personnel responded to a 911 call about two people possibly dead at Brighton Towers at 10:30 a.m., Syracuse Mayor Ben Walsh said. First responders said two people were dead on arrival and another was taken to a local hospital with «altered mental status.»

The identities of the people who died have not been released. No other deaths were reported.

Brighton Towers Senior Living Apartments in Syracuse, NY, on Wednesday.WSTM-NBC3

Three responding police officers began to feel ill and were taken to SUNY Upstate Medical University for evaluation, Fire Department Capt. Matthew Craner said in a statement.

A firefighter who was part of the initial response was also taken to the hospital, he said.

All of the responders had symptoms ranging from nausea to elevated heart rates, Craner said.

Several hospital staff members also began feeling ill, and the emergency department closed for approximately 2 hours and 15 minutes to «manage patients and prevent further exposures,» the statement said.

Operations at the hospital have returned to normal and the nine patients who were treated there have been discharged, the hospital said in a statement.

A Haz-Mat Response Team vehicle on the scene at Brighton Towers Senior Living apartments on March 1, 2023.
A hazmat response team vehicle at Brighton Towers Senior Living Apartments on Wednesday afternoon.WSTM

People started feeling sick about 30 minutes after being exposed to the substance, Onondaga County Executive J. Ryan McMahon told reporters.

The fire department’s hazmat team returned to assess the building for possible substance exposure. The team evacuated 18 units on the sixth floor of the Brighton Towers building and firefighters monitored the air.

Residents on the sixth floor were able to return to their apartments by 6 p.m., Craner said in the statement.

“Firefighters were unable to definitively identify a specific hazard,” the statement said. «The investigation continues into what caused the deaths and the symptoms.»

Elizabeth Malina and joseph cradduck contributed.