Library staff closed the Baldwin Public Library Tuesday after a dozen employees in the branch complained of nausea and detected odors or fumes in the air, Nassau police and fire officials said.
Officials shut the library on Grand Avenue shortly after calling firefighters about 11 a.m., said 2nd Deputy Chief Robert Brancato of the Baldwin Fire Department, who added that the victims had elevated levels of carbon monoxide.
"They apparently were exposed to carbon monoxide at some point," he said.
Firefighters tested the air inside the building but could not detect the source of the problem after surveying the heating and ventilation system, Brancato said.
"There was nothing we found in the building," he said.
Officer Maureen Roach, a police spokeswoman, said police officers were dispatched to the scene as well after receiving a call at 11:06 a.m.
Of the 12 people who were stricken, seven were taken to Nassau University Medical Center in East Meadow and five declined to be treated. It was unclear if they remained hospitalized late Tuesday afternoon.
The library's website and a greeting on its phone informed people of a problem but provided no details about the cause of the shutdown.
A notice on the site read that the library was closed as of noon Tuesday, and instructed visitors to "Please call to find out when we will be reopening."
Similarly, a phone greeting said the library was closed because of an emergency as it urged people to call the library to check whether it was open before making a trip to the building.
The Baldwin school district issued an advisory saying the library was closed after staffers began feeling ill. The notice said fire officials checked for the presence of carbon monoxide and other irritants but that no contaminants were found.
It said the library would not likely be open for the rest of the day. It would normally remain open from 9 a.m. until 9 p.m. on a weekday, according to the library's website.
"The library will reopen when their testing is completed, most likely not today," read the schools notice.
With Carl Corry