An evaluation study of UN and US test procedures for solid chemical oxidizers (SCOs) was performed by the National Institute for Occupational Safety and Health (NIOSH) for the US Department of Transportation (DOT). Eighteen solid oxidizers were mixed with cellulose (UN test) and fourteen with sawdust (US test). Burning times were compared with those form reference mixtures. Twenty-nine percent of the UN published hazard classifications were confirmed using potassium bromate (KbrO3) with a particle size from 150 to 300 micrometers. For sizes of this carcinogen less than 150 micrometers, 71% were confirmed. In tests with the proposed noncarcinogenic potassium chlorate (KClO3) reference less than 300 micrometers in size, 76% of the classifications were confirmed. Classifications that were based on the US protocol, using three different reference chemicals specified were confirmed for 21% of the cases. The data provides a basis for adopting a modified version of the UN protocol featuring the replacement of the bromate standard with potassium chlorate. If it is decided to retain the US protocol, then similar changes are recommended. There would be then only minor differences between the US and UN protocols. Proposed future work is discussed, including modeling, information retrieval, particle size effect on burn time, and the reactivity of liquid oxidizers in open and semi-confined environments. Approximately 800 combustion tests were conducted.