Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Measured CO Concentrations at NIST IAQ Test House from Operation of Portable Electric Generators in Attached Garage – Interim Report



Steven J. Emmerich, Liangzhu Wang


The U.S. Consumer Product Safety Commission (CPSC) is concerned about the hazard of acute residential CO exposures from portable gasoline powered generators that can result in death or serious and/or lasting adverse health effects in exposed individuals. Such exposures have increased in recent years. Based on CPSC data, the total yearly estimated non-fire related CO deaths for each of the years 1999 through 2002 are 109, 138, 130 and 188, respectively. Since 1999, the percentage of estimated CO poisoning deaths specifically associated with generators has been increasing annually. In 1999, generators were associated with 7 (6 %) of the total yearly estimated CO poisoning deaths for that year. In 2000, 2001 and 2002, they were associated with 19 (14 %), 22 (17 %) and 46 (24 %) deaths out of the total estimates for each of those years. Typically, these deaths occur when consumers use a generator in an enclosed or partially enclosed space or outdoors near an open door, window or vent. CPSC has measured the emissions from generators in a small test chamber but the operation of such generators in real buildings has not previously been studied. Additionally, CPSC has contracted with the University of Alabama to develop prototypes of generators modified to mitigate the emission of excessive amounts of CO when operated in enclosed spaces. In conjunction with these other efforts, NIST has conducted a series of tests of CO concentration in an actual building. This letter report presents data from a series of tests of both modified and unmodified generators operated in the attached garage at the NIST manufactured house. Further analysis of this data will be presented in future reports.


Indoor air quality, carbon monoxide, field study, combustion engine, portable generator, oxygen depletion


Emmerich, S. and Wang, L. (2011), Measured CO Concentrations at NIST IAQ Test House from Operation of Portable Electric Generators in Attached Garage – Interim Report, Other, National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed June 14, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created July 8, 2011, Updated February 19, 2017