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HOUSTON (AP) — Authorities are trying to determine what sickened three lab workers at the M.D. Anderson Cancer Center complex.

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The incident happened Thursday morning at a two-story Houston research building that also houses University of Texas campus police.

Police spokesman Edward Cavazos says the building was evacuated for about 90 minutes after three workers reported feeling ill. Cavazos says none has life-threatening injuries.

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Cavazos says one person reported feeling overheated and in distress. He says two other lab workers then said they also felt uncomfortable.

He had no additional information on what caused the workers to become sick, but says the public was not in any danger.

Dozens of workers who evacuated the building, as a precaution, were allowed to return around 9:15 a.m.

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