Authorities ordered an evacuation of the Holiday Inn in Carle Place on Thursday to investigate a "noxious odor" and found a guest had committed suicide by concocting a fatal mix of chemicals, Nassau police said.
Officers were called to the Old Country Road lodging about 3 p.m. and smelled fumes on the second floor, police said.
Scores of guests and employees were evacuated to the Chateau Briand catering hall next door as hazmat and emergency services units investigated.
Ambulances and Carle Place fire trucks stood by, a response that shut down westbound Old Country Road for hours.
In a second-floor room, hazmat units found an Elmont man, 21, unconscious, and he was pronounced dead at 8:48 p.m. in what police described as a "chemical-induced suicide."
Chemicals were collected, but exactly what they are won't be known until tests are done, police said.
Six Holiday Inn employees were examined as a precaution, but they refused medical treatment, police said.
About 100 Holiday Inn guests and workers streamed back to the hotel about 9:40 p.m., shortly after children and families were preparing to sleep on pillows of folded tablecloths at the catering hall.
Tom Wright, Chateau Briand's director, said his unexpected guests were given free dinners. He had taken them in about 4:30, after getting a call for help.
"We got a phone call from the operations manager over at Holiday Inn," Wright said early Thursday night. "Instead of having them all stand outside, we said we would accommodate them over here, so we set up a room upstairs with coffee, cheese, platters and all these different things to warm them up a little bit."
Many of the guests were on Long Island to take care of Sandy issues, including contractors and employees of the Federal Emergency Management Agency, Wright said. Others were families with children, he said.
Wright said he did not mind the extra duty on a night when he had three functions and 350 catering guests.
"We were just happy to be there in other people's time of need," he said.