BETHLEHEM, Pa. (AP) – A mysterious odor at a Pennsylvania business park has sickened workers for the second time this week, sending several to the hospital with nausea and headaches.

About 400 people were made to leave businesses in Hanover Township just north of Bethlehem on Thursday morning.

Township Manager John Finnigan says five people went to the hospital with complaints of nausea and headaches.

By afternoon workers were being allowed back into the building.

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The ordeal follows an odor complaint that caused evacuations and sent 31 people to hospitals for treatment of symptoms like vomiting and dizziness on Monday.

Finnigan says some complained of a gas smell when the heat turned on in the building Thursday.

Crews found no gas leak. Meters showed no signs of gases that could cause symptoms.

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