Comment on "Isocyanic acid (HNCO) and its fate in the atmosphere: a review" by M. D. Leslie, M. Ridoli, J. G. Murphy and N. Borduas-Dedekind, Environ. Sci.: Processes Impacts, 2019, 21, 793

Can 1 ppb of isocyanic acid in air cause 100 mu M in the blood stream? The impact of indoor and outdoor isocyanic acid (HNCO) levels may be of concern to human health. HNCO is well soluble in water but hydrolyzes rather slowly. Recently determined thermodynamic data and HNCO hydrolysis kinetics indicate that high blood levels might be reached. This data has been complemented with a brief assessment of kinetic information from the (bio)chemical and medical literature about carbamoylation reactions with proteins, indicating that other bodily elimination mechanisms cannot be ignored. Expected incremental blood levels corresponding to 1 ppbv HNCO in air are estimated to be in the low nM range. Acute toxic effects therefore seem unlikely, but chronic exposure to higher concentrations may still be of significance.