In vivo and in vitro biological effects of the flame retardants tris(2,3-dibromopropyl) phosphate and tris(2-chlorethyl)orthophosphate.

Tris(2,3-dibromopropyl)phosphate (Tris-BP) and Tris(2-chloroethyl) orthophosphate (Genomoll P) were analyzed for mutagenic and carcinogenic activity in several in vitro and in vivo mammalian systems. In the in vitro tests both Tris-BP and Genomoll P increased sister chromatid exchanges in V79 cells with a dose-response relationship for Tris-BP. The mutation assays using the same cells (HGPRT locus) were negative. Both compounds showed positive results in the transformation of Syrian hamster embryo cells. A very low frequency of transformation in the C3H10T1/2 cells was obtained; we consider this result essentially negative. In the in vivo assays Tris-BP gave positive and Genomoll P questionable results in the micronucleus test performed on Chinese hamsters. Both gave negative results in short-term skin tests. In the long-term skin tests, Tris-BP showed an initiating activity which was not observed with Genomoll P. When they were used as promoters both chemicals increased the incidence of lung adenomas in mice. Comparatively, Genomoll P is far less hazardous than Tris-BP.