(E)-1,1,1,2,2,5,5,6,6,6-Decafluoro-3-hexene (HFO-153-10mczz-E).

(E)-1,1,1,2,2,5,5,6,6,6-Decafluoro-3-hexene (HFO-153-10mczz-E) (CASRN 1256353-26-0) is a volatile liquid proposed for use as a new low global-warming potential dielectric fluid in cooling applications. Workplace exposures are expected to be by inhalation exposure. The substance has low acute inhalation toxicity as indicated by a 4-h inhalation LC₅₀ value of approximately 8000 ppm. A suite of in vitro assays was negative for skin and eye irritation as well as for skin sensitization potential. The chemical did not induce cardiac sensitization up to 5000 ppm. Repeated inhalation exposure in rats for 4 or 13 weeks did not produce any effects attributable to the substance at 3000 ppm, the maximum tested concentration. No indications of developmental or reproductive toxicity were observed in studies in rats, also conducted with a maximum concentration of 3000 ppm. There was no indication of genotoxicity in the Ames assay, an assay with human TK cells, chromosome aberration in cultured human lymphocytes, or an in vivo rat micronucleus assay. The critical study for the development of the 8-hour TWA WEEL is the 13-week inhalation toxicity study with a NOAEC of 3000 ppm (32,400) mg/m³). This inhalation NOAEC was adjusted by application of appropriate uncertainty factors to account for interindividual variability, subchronic to chronic exposure extrapolation and other sources of uncertainty. A WEEL value of 200 ppm (2160 mg/m³) is expected to provide an acceptable margin of safety for potential adverse health effects in workers.