A variety of symptoms including nausea, vomiting, dizziness and irritation of the eye, nose and throat occurred in 70 of 84 assemblers in a Cincinnati, Ohio electrical components manufacturing facility on December 5, 1988. The employees had shortly before noted an odor which coincided with the introduction of steam for humidification which was derived from the facility boiler. A NIOSH investigation found that in mid September, two corrosion inhibiting chemicals, diethylaminoethanol (100378) (DEAE) and cyclohexylamine (108918) (CHA) had been added to the boiler at four times normal strength. During the next 2.5 months the boiler was idle. NIOSH has investigated three other incidents of illness related to exposure to boiler steam that contained corrosion inhibiting chemicals. In light of these findings, the authors conclude that the use of amine corrosion inhibiting chemicals in boiler steam to humidify occupied buildings should be discontinued. At least one major supplier of corrosion inhibiting chemicals recognized the potential health hazards of DEAE and in 1983 warned all of its customers against such use.