Carbon Monoxide Concentrations and Carboxyhemoglobin Profiles from Portable Generators with a CO Safety Shutoff Operating in a Test House

The U.S. Consumer Product Safety Commission (CPSC) is focused on addressing the hazard of acute carbon monoxide (CO) poisoning of consumers from portable generators that can result in death or serious and/or lasting adverse health effects in exposed individuals. Under an interagency agreement with CPSC (CPSC-I-17-0023), the National Institute of Standards and Technology (NIST) conducted a series of tests to characterize the indoor CO concentrations and the associated calculated carboxyhemoglobin (COHb) profiles on simulated occupants resulting from portable generators operating in or near a test house. The tests are intended to provide information to enable CPSC staff to make comparisons of residential CO exposures reflecting operation of current designs of portable engine-driven electric generators, inside or near homes or in attached garages, versus operation of portable generators equipped with a CO safety shutoff device. This report presents measured CO data and calculated COHb levels based on that CO data from tests conducted with five different generators under various operational and environmental conditions. Those data were then used to evaluate how well the indoor air quality model CONTAM can predict CO levels in the garage and the house in support of a planned study that CPSC staff will use to evaluate the impact of CO mitigation requirements in two recently-published voluntary standards.