Nassau police and fire departments received numerous calls Friday afternoon about a pungent odor on the South Shore, the source of which has not been pinpointed, officials said.
The smell does not appear to be natural gas, and may be caused by a garbage barge or sewage treatment plant, officials said.
The county's Office of Emergency Management said in a Facebook post that "when the odor is this widespread, it may be stemming from an offshore issue."
Fire departments that received calls about the smell between about 4 p.m. and 4:30 p.m. included, Long Beach, Point Lookout, Freeport, Merrick, North Merrick, Baldwin and Levittown.
By 5:30 p.m., county fire control said the smell seemed to have moved toward the north.