Evaluation of acute toxicity in liquid organic hydrogen carriers via experimental and computational approaches

Liquid organic hydrogen carriers (LOHCs) are promising hydrogen storage materials, yet their toxicological properties remain insufficiently characterized. This study evaluated the acute toxicity of selected LOHCs following OECD Test Guideline 423 to determine lethal dose 50 % (LD50) values in rodents. The toxicological properties of various LOHC candidates, including dibenzyltoluene, N-ethylcarbazole, and hydrogenated pyridine-based compounds, were assessed through experimental and computational approaches. The results indicate that toxicity varies with hydrogenation state, with some fully hydrogenated forms exhibiting increased toxicity. Among the tested compounds, dibenzyltoluene exhibited the lowest toxicity, whereas some pyridine-based LOHCs induced neurological effects of varying severity. A moderate correlation was observed between the predicted and experimental toxicity values, suggesting that computational models provide useful insights but require careful interpretation. These findings contribute to the systematic assessment of LOHC toxicity and provide insights into their safety for industrial hydrogen storage applications. • The acute toxicity of LOHCs was assessed via OECD Test Guideline 423. • The toxicity levels were comparable to those of conventional fuels such as diesel and gasoline. • Dibenzyltoluene exhibited the lowest toxicity, whereas hydrogenated pyridine-based LOHCs caused severe neurological effects. • QSAR-based aquatic toxicity predictions for LOHCs are less reliable because of high log K OW variability.