The United States uses two to three million kilograms of cyclohexylamine (CHA) each year as a corrosion inhibitor in steam lines and boilers. Many existing boiler heating systems vent CHA treated steam into occupied space to humidify indoor air. As a result, CHA has been implicated in acute toxic events arising from steam humidification. A study was undertaken at the East Carolina University School of Medicine to accurately assess exposure to CHA, predict conditions or circumstances which could lead to a toxic event, and make recommendations based on findings. Within the study areas, CHA levels averaged 6.6 parts per billion (ppb), well below the present OSHA Permissible Exposure Level of 10 parts per million (ppm). A material balance helped identify the additive feed mechanism as the control point most likely to influence the occurrence of a toxic event arising from humidification with steam containing volatizing amine corrosion inhibitors. The automatic feed device should be carefully maintained and manual dosing of the boiler should never be permitted within the Medical School Complex.