An investigation continues to determine the source of the problem which led to the evacuation of a major office building in downtown Omaha last week.
Approximately 2,000 workers fled First National Tower last Thursday after many developed breathing problems.
Workers reported respiratory problems, burning eyes, dizziness, pain in their throats and chests, as well as nausea to emergency crews which arrived at 16th and Dodge Streets Thursday morning. Omaha police report at least seven people from the 8th floor reported symptoms, but workers on other floors sought medical help as well. In all, 16 people were hospitalized.
An inquiry into the cause has focused on a descaling solution on a humidifier. Medical officials question whether fumes from a product called Rydlyme might have caused the breathing problems reported. Omaha fire officials, though, have not officially determined a cause.
University of Nebraska Medical Center physicians speculate hydrogen chloride gas caused respiratory problems.
The evacuation of the building occurred Thursday morning. Workers were allowed to re-enter the building later in the day to gather belongings. It was closed overnight and re-opened Friday morning.