Residents of the West Harlem area may notice an odor Monday morning, as crews repair a natural gas pipeline.
Four people were treated after more than 100 people were evacuated from 330 West 42nd Street.
The temporary building on the north lawn of the complex was evacuated Tuesday, but staff and diplomats were allowed to return a few minutes later.
Children from grades 2, 3, and 4 were evacuated and taken to a nearby school.
The school will be closed, probably all week long, so the soil and water can be sampled and more air testing can be done.