Officials in Chester County are still unsure what caused several employees at a store in the Coventry Mall to become sick just before closing Tuesday night.

Around 9:30 p.m., all five employees of the Verizon store in North Coventry Twp. reported chest pains and nausea.

Fire crews checked out the store's heating and ventilation, but found nothing wrong.

Nothing was found in nearby stores vents either.

There's no word on the condition of the employees.