Estimation of dioxin emission from fires in chemicals

The formation of the 17 toxic 2,3,7,8-substituted PCDDs and PCDFs during co mbustion of selected chemicals were measured by high-resolution GC/MS. The 16 chemicals studied were commonly used chlorinated pesticides, industrial chemicals, and PVC. In a series of experiments carried out in a DIN 53,436 furnace, 2.5 g of these compounds were burned at 500 degrees C and 900 degr ees C, respectively. The resultant yields ranged from 740 ng ITEQ/g for pen tachlorophenol, to below 0.01 ng ITEQ/g for PVC and dichlobenil. The result s show that some chemicals generate PCDD/F in very high possibly dangerous - amounts during burning, whereas others generate insignificant amounts. Th e influence of scale were studied for chlorobenzene and 4-chloro-3-nitro-be nzoic acid in additional experiments, carried out in a cone calorimeter bur ning 20 g substance, and in ISO 9705 room test burning about 50 kg. A good agreement between the results for large and small scale indicated that form ation of PCCD/F during a fire may be estimated from laboratory experiments. This suggest laboratory test may be used to screen for chemicals posing a hazard for release of PCDD/F during fires. (C) 1999 Elsevier Science Ltd. A ll rights reserved.