Exposure Risks of Trans-Perfluoro (4-Methyl-2-Pentene) Byproduct in C6F12O Fire Suppressants: Toxicological Mechanisms and Implications.

C₆F₁₂O fire agent is widely used in various fire extinguishing scenarios due to its excellent properties. The most abundant byproduct in C₆F₁₂O fire extinguishing agent is perfluoro (4-methyl-2-pentene) (C₆F₁₂). Currently, there is a lack of reports on the toxic mechanisms of trans-C₆F₁₂. This study investigated the acute oral toxicity of trans-C₆F₁₂ in rats, the damage mechanisms to major organs, and evaluated the inflammatory status of various organs. The experimental design comprised four treatment groups: a control group, a low-dose group (250 mg/kg), a medium-dose group (500 mg/kg), and a high-dose group (750 mg/kg), encompassing the range from sublethal to lethal concentrations. The median lethal dose (LD50) for trans-C₆F₁₂ revealed its mild acute toxicity, with male rats exhibiting significantly higher sensitivity. Clinical observations showed that trans-C₆F₁₂ oral exposure caused symptoms such as lethargy and reduced appetite. Pathological analysis revealed that trans-C₆F₁₂ primarily caused significant damage to the respiratory and urinary systems, particularly in lung and kidney tissues. Additionally, moderate damage was observed in the liver, heart, and spleen, whereas only mild pathological changes were detected in the classical hippocampus, and no effects were observed in ocular tissues. Further analysis of the inflammatory cytokine IL-1β levels showed that lung and kidney tissues were more sensitive to the toxicity of trans-C₆F₁₂, exhibiting significant inflammatory responses. In contrast, the inflammatory responses in other organs were relatively weak. This study revealed the toxicity of trans-C₆F₁₂ and its toxicological mechanisms, providing important references for the safe use of C₆F₁₂O fire extinguishing agent.