Four people were taken to the hospital last month after feeling sick while in a laboratory at Yale Medical School in New Haven.
Three people started feeling light-headed while working in lab at 330 Cedar St. around 3:30 p.m. on Feb. 18, according to Connecticut Department of Energy and Environmental Protection.
DEEP officials said two people passed out, and all three were taken to Yale-New Haven Hospital.
A fourth person, who was in the lab earlier, had similar symptoms but went home.
"Nauseous, lightheaded and faint, but mostly weakness, they felt like they couldn't move, two ended up being on the floor when we made entry," said New Haven Fire Chief John Alston.
The lab was shut down after this happened, as an investigation was underway.
A week later, Yale officials said the individuals had all used the same single-serve coffee machine that day, before feeling sick.
That coffee pot, among other items inside the lab, was tested.
The test indicated a presence of sodium azide, which is commonly found in laboratories and used as a preservative.
The coffee machine was not connected to a water source, and the area was declared to be safe by Yale Environmental Health and Safety.
"At the same time, we are reviewing security and safety procedures with our public safety team. Out of an abundance of caution, we have let the Yale School of Medicine community know that the symptoms of exposure to sodium azide are dizziness, headache, nausea and vomiting, rapid breathing, and rapid heart rate," Officials said in a press release.
The Yale Police Department is continuing its investigation, in collaboration with local, state and federal police.
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