This paper presents a feasibility study of a wearable computing system to protect construction workers from carbon monoxide poisoning. A pulse oximetry sensor has been integrated into a typical construction helmet to allow continuous and non-invasive monitoring of workers' blood saturation levels. To show the feasibility of monitoring for carbon monoxide poisoning without subjecting users to dangerous conditions, a prototype for monitoring blood O2 was constructed and tested during a user study involving typical construction tasks to determine its reliability while undergoing motion. Because monitoring for blood O2 and CO involve the same principles and technologies, if monitoring O2 is feasible, then monitoring for CO will be feasible as well. The results of this initial study show that integrating an oximeter into a construction helmet will warn the user of impeding carbon monoxide poisoning with a probability greater than 99%.