Carbon monoxide (CO) from the use of biomass solid fuels has caused several fatalities in the United Kingdom. This study was undertaken to evaluate the amount of CO from five species of wood sawdust, and charcoal with a case study of CO in a confined ISO container. Laboratory experiments were conducted at temperatures between 350 and 600 o C under flowing air. Results showed a strong dependence of CO emissions on temperature and airflow. Sawdust emitted CO levels as high as 298 mg/g while charcoal released 495 mg/g as highest. The CO emissions recorded in the ISO container were above the recommended exposure limits due to poor ventilation.