An atopic (one with multiple environmental allergies) instructor reported asthma-like symptoms when working in his classroom. He complained of "toxic mold" in his classroom and formaldehyde off-gassing from furniture as the cause of his problems. Others in the building were also concerned. A comprehensive health evaluation was performed. A visual inspection revealed signs of an old water leak with no obvious evidence of mold amplification. The furniture was also inspected. There was on going renovation of this old building occurring in nearby offices. A pathway with enough air pressure differential was also found to be exposing this instructor to allergens probably carried on the construction dust/ debris. The occupants were so advised and the instructor was temporarily transferred to an existing trailer classroom for the duration of the renovation. Dust control modifications were recommended to the construction team to prevent widespread distribution. The instructor returned to his classroom after the renovation without a medical incident. Health-based management of the situation by trained health professionals identified the root cause of the problem and addressed the fears of the occupants through effective risk communication, mitigating potential problems.