Barrel Burning: Missing Dioxin Link

Dioxins emitted from daily open-barrel burning of just two households (a common practice in many rural areas) can equal emissions from a modern 200-ton-per-day municipal waste combustion facility, according to a recent EPA study. The disproportionately high emissions from barrel burning occur because of a combination of conditions considered “worst case” for dioxin formation: low combustion temperature; oxygen-starved conditions; poor gas-phase mixing; presence of chlorine sources; and high particulate matter (PM) loading. In an interesting twist, dioxin emissions for an “avid recycler” of household waste were much higher than for a “non-recycler.” A number of factors contributed to this difference, but most of it is probably due to the higher proportion of PVC in the recycler’s waste.

The barrel burning research may have solved a long-standing puzzle of the EPA 1994 Draft Dioxin Reassessment. The mass balance of the 1994 assessment showed considerably higher estimates of depositions than emissions. One explanation for this discrepancy would be a significant

unidentified source of emissions. The newly discovered magnitude of barrel burning emissions, coupled with its suspected prevalence across the country, makes it a great candidate as this unaccounted-for source. Backyard barrel burning of household waste is still quite common and legal in many parts of the country. For example, an Illinois study reports that 40 to 50% of its rural residents barrel burn at least some of their household waste.