The uncontrolled burning of household waste in barrels has recently been implicated as a major source of airborne emissions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). A detailed, systematic study to understand the variables affecting emissions of PCDD/Fs from burn barrels was performed. The waste composition, fullness of the barrel, and the combustion conditions within the barrel all contribute significantly to determining the emissions of PCDD/Fs from burn barrels. The study found no statistically significant effect on emissions from the Cl content of waste except at high levels, which are not representative of typical household waste. At these elevated Cl concentrations, the impact of Cl on PCDD/F emissions was found to be independent of the form of the Cl (inorganic or organic). For typical burn conditions, most of the PCDD/F emissions appear to be associated with the later stages of the burn when the waste is smoldering. Polychlorinated biphenyls (PCBs) were also measured for a subset of the tests. For the nominal waste composition, the average emissions were 76.8 ng toxic equivalency units (TEQ)_WHO98 /kg of waste com busted, which suggests that uncontrolled burning of household waste could be a major source of airborne PCDD/Fs in the United States.