United States Department of Transportation
i
Inhalation Toxicology: XII. Comparison of Toxicity Rankings of Six Polymers by Lethality and by Incapacitation in Rats
-
1991-12-01
[PDF-581.11 KB]
Details:
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Geographical Coverage:
-
Corporate Publisher:
-
Abstract:Polymeric aircraft cabin materials have the potential to produce toxic gases in fires. Lethality (LC50) in animal models is a standard index to rank polymers on the basis of their combustion product toxicity. However, the use of times-toincapacitation (tis) may be more realistic for predicting relative escape times from a fire environment. Therefore, LC50s and tis for six pure polymers of different chemical classes were determined and compared. The polymers were polyamide (I), polystyrene (II), Nylon 6/6 (III), polysulfone (IV), polyethylene (V) and chlorinated polyethylene (VI). In the study, male Sprague-Dawley rats (150-250 g), 12 animals per fuel loading, were exposed to the pyrolysis products from selected weights of each polymer for 30 min. in a 265-L combustion/exposure system, and LC50s were determined following a 14-day observation period.
For each polymer, tis were also measured at 16 g, that is, 60 mg/L, and at their respective LC50s using the inability of rats (n _ 12) to walk in rotating cages as a criterion for incapacitation. The LC50s (mg/L) of the polymers had the order of I (45.7) < II (56.6) _ III (58.1) < IV (63.2) < V (75.5) < VI (87.5), while their tis (min.) at 16 g (60 mg/L) had the order of III (6.6) _ I (7.3) < V (11.7) _ II (12.0) < VI (18.4) < IV (21.1). Based on the tis (min.) at LC50s, the polymers were grouped into III & V (10.5, 11.0); I, II & VI (14.1-15.0); and IV (19.5). The two toxicological end points, LC50 and ti, did not exhibit the same relative toxic hazard rankings for these polymers. Also, tis were not equal at the LC50 concentrations, a condition of equal lethality. These findings demonstrate the possible involvement of different mechanisms of action for the combustion products of these polymers at the selected end points.
-
Format:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type:
