Breathing zone and environmental samples were analyzed for total and respirable dust, crystalline silica (14808607), asbestos (1332214), hexavalent-chromium (18540299) (Cr+6), carbon-monoxide (630080), nitrogen oxides, and trace metals at a waste to energy conversion facility. The facility typically incinerated municipal trash at approximately 1400 degrees-F and produced steam in two 360 ton capacity boilers that was sold directly or converted to electricity by means of an on site turbine. The facility operated 24 hours a day and usually employed 50 persons. Workplace temperature and humidities were also measured. Total dust concentrations ranged from 1.2 to 11.5mg/m3. Breathing zone respirable dust concentrations were 0.3 to 0.7mg/m3. Significant concentrations of airborne aluminum (7429905), cadmium (7440439), chromium (7440473), copper (7440508), iron 7439896), nickel (7440020), and lead (7439921) were detected. Soluble Cr+6 was not detected. Insoluble Cr+6 was detected at concentrations on the order of 0.001mg/m3. Significant amounts of amosite (12172735) were detected in the breathing zone and environmental samples. Crystalline silica and nitrogen oxides were not detected. Except for one sample that yielded a concentration of 5 parts per million, carbon-monoxide was not detected. Workplace ambient temperatures ranged from 83 to 115 degrees and relative humidities from 18 to 50%. The author concludes that workers at the waste to energy facility are potentially exposed to high concentrations of total dust, metals, and asbestos and experience heat stress problems.