Document mqBr6RaDwGGmd8qOLjRJRqbjB

/W m1/ A COMPARATIVE REVIEW OF THE COMBUSTION TOXICITY OF POLYVINYL CHLORIDE Robert K. Hinderer The BF Goodrich Company Environmental Health Department 500 South Main Street Akron, Ohio 44318 (Received October 10, 1983) (Revised May 14, 1984) INTRODUCTION Over the past fifteen years considerable attention has been given to the combustion toxicity of materials. This concern has largely been the result of a recognition that most fire deaths result from the inhalation of toxic gases, particularly carbon monoxide (Harland and Wooley, 1979; Halpin and Berl, 1978; and Birky et al, 1979). Although the relative importance of toxicity in the overall fire hazard of a material is not known, it is recognized to be one of the many factors, (i.e. quantity, configuration, compartment volume and surface area, ven tilation, flammability and combustion properties, presence and type of ignition source, fire protection systems, building occupancy, and code enforcement) which influence fire hazard (likelihood or probability of in jury). One of the materials which has drawn particular attention over the years is polyvinyl chloride (PVC). Many early attempts to compare the ' combustion toxicity of PVC and other materials with natural products such as wood involved the analysis of combustion gases and their respective toxicities. While qualitative and quantitative differences were found, many materials released similar types, namely commonly known asphyxiants such as carbon monoxide (CO) and carbon dioxide (COj), irritants, and complex organic chemicals. In the case of PVC and wood, both materials produced CO and COi and complex organics. However the subject of real contention was the production of irritants-- Reprinted from Journal of FIRE SCIENCES, VOL. 2--JANUARY/FEBRUARY 1984 2644c013 Robert K. Hindered and Marcelo M. Hirschlez*1 The Toxicity of Hydrogen Chloride and of the, 1 Smoke Generated by Poly (Vinyl Chloride), Including Effects on Various Animal Species, and the Implications for Fire Safety ' REFERENCE: Hinderer, R. K_ and Hirscfaler, M. M^, "The Toxicity of Hydrogen Chloride * and of the Smoke Generated by Poly (Vinyl Chloride), Including Effects on Various Animal Spedes, and the Implications for Fire Safety," Characterization andTaxidt? ofSmoke, ASTM S171082r H. K. Hasegawa, Ed, American Society for Testing andMaterials, Philadelphia, 1990, pp. 1-22. > . . x- ABSTRACT: Toxicity ofsmoke is only oneofmany factors drtermining the hazard orthe risk resulting if a product were involved in a fixe in a specific socnarib. Other Actors include: amount of smoke (Lc^ concentration of combustion products in the atmosphere), rate and quantity ofheat release, mass loss rate, and flame spread rate, as wefl as such "eaviionmentaln factors as ignition source characteristics, fire detection and suppression devices, building occu pancy, and code enforcement. A factor almost specific to the smoke generated from burning poly (vinyl chloride) (PVC) is the decay ofhydrogen chloride (HQ) by reaction with building surfaces. The values of smoke toxic potency measured 'mil also be affected by a number of parameters, including combustion znode^.exposure mode, toxicological end point, and statis- tical analysis ofresults. . v '. A crucial factor, often overlooked, is the choice ofan animal modd appropriate as a surro- - gate for man, and its validation. Test.animaW are frequently chosen'on the basis of conve- nience, cost, or other characteristics (e^, sensitivity) rather than'bccausc of their similarity to man. This is particularly important in combustioa toxicology, where one test species may not ' be a good modd for all the mryorcombustion.products generated. Thus, comparisons ofmate rials producing different major combustion products must be approached with caution to ensure that any apparent differences encountered in tests are not simply an artifact of test species. Over recent years, increasing evidence has surfaced that some rodent species are poor models ; for the toxic response ofman to irritantgases or to smoke-containing irritants. Studies on HQ (as a pure gas) and on the smoke generated from the burning ofPVC have indicated that mice are much more sensitive than rats. More importantly, they are much more sensitive than pri mates. It has also been established that rats are a good model for primates in terms ofthe lethal effects of irritant products. Although primates have survived 15-min exposures to 10 000 ppm of HCI, 2500 ppm is lethal to mice. Moreover, under the same exposure conditions, mice will die at PVC smoke levels four to seven times lower and HQ levels seven to ten times lower than - those at which rats wilL In contrast, lethal doses ofasphyxiants such as carbon monoxide (CO) - are similar in rats and mice. These results indicate that the response of the mouse significantly overestimates the toxic potency of HQ and of PVC smoke to man. BFG51082KEY WORDS: PVC, HO, poly (vinyl chloride), hydrogen chloride, smoke toxicity, fire haz ard, animal models, toxic potency, smoke, fire ` Manager of Toxicology, BF Goodrich Corporate Environmental Health Department, Bath, OH 44313. 1 R&D Manager, Fire Sciences, BF Goodrich Geon Vinyl Division,.Technical Center, Avon Lake, OH 44012. f