Toxicological evaluation of 6:2 fluorotelomer alcohol.

6:2 fluorotelomer alcohol (6:2 FTOH; CF3[CF2]5[CH2]2OH, CAS# 647-42-7) was evaluated for acute, genetic, and subchronic toxicity using in vitro and in vivo methods. In rats, 6:2 FTOH was considered to be slightly toxic by the oral (LD50=1,750 mg/kg), and dermal (LD50 > 5,000 mg/kg) routes. In rabbits, 6:2 FTOH was not a primary skin or eye irritant, and it did not produce a dermal sensitization response in mice. In a 90-day subchronic study, 6:2 FTOH was administered to rats by oral gavage (0, 5, 25, 125, 250 mg/kg/day). Mortality was observed at 125 and 250 mg/kg/day; deaths occurred after approximately three weeks of dosing and continued sporadically. The NOAEL in the subchronic study was 5mg/kg/day based on hematology and liver effects. 6:2 FTOH was not mutagenic in the bacterial reverse mutation test or in the mouse lymphoma assay and was not clastogenic in a chromosome aberration assay in human lymphocytes. The hazard classification for human health endpoints of 6:2 FTOH according to the United Nations Globally Harmonized System of Classification and Labeling of Chemicals (GHS) is Category 4 for acute oral toxicity based on an LD50 of 1,750 mg/kg. Other acute health endpoints including eye and skin irritation, skin sensitization, as well as genotoxicity, did not meet the criteria for hazard classification. Benchmark Dose Analysis was performed on the most sensitive endpoints from the 90-day oral gavage study and these levels were all above the study NOAEL of 5mg/kg/day. For risk assessment purposes, the recommended point of departure is the more conservative study NOAEL of 5mg/kg/day.