Benzoic acid (inhalable fraction): MAK Value Documentation, addendum - Translation of the German version from 2023

The German Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission) has re-evaluated the data for benzoic acid [65-85-0] to derive an occupational exposure limit value (maximum concentration at the workplace, MAK value) for the inhalable fraction. The critical effects are severe irritation in the eyes and lung toxicity. For this reason, irritation is assumed to occur also in the upper respiratory tract. Inhalation studies investigating the inhalable fraction of benzoic acid in humans or animals are not available. Therefore, data for similarly strong acids are used for the evaluation of the local effects on the respiratory tract. In analogy to the MAK value derived for phosphoric acid, a MAK value of 2 mg/m³ I (inhalable fraction) has been established. This represents the "worst case" for benzoic acid due to its weaker acidity. Peak Limitation Category I with an excursion factor of 2 has been set in analogy to the classification made for phosphoric acid. There are no valid prenatal developmental studies of benzoic acid available. Benzoates are classified in Pregnancy Risk Group C at the MAK value of 10 mg/m³. As the benzoate anion is responsible for the systemic effects of benzoic acid and the acid has a lower MAK value, Pregnancy Risk Group C is valid also for the inhalable fraction of benzoic acid at the MAK value of 2 mg/m³. Dermal uptake is expected to contribute to systemic toxicity and benzoic acid remains designated with "H" (for substances which can be absorbed through the skin in toxicologically relevant amounts).