A putative adverse outcome (AO) pathway (AOP) related to sulfuric acid mists carcinogenicity. Upper panel: An AOP framework that consists of a molecular initiating event (MIE) leading to an adverse outcome through the key events (KEs) at various biological levels (ranging from cells to organ systems) and these KE relationships. Lower panel: The MIE cause a low pH, which can result in acute or chronic abnormal biological states. Based on the putative AOP, a possible mechanism of genetic instability relates to low pH, which can induce tumorigenesis or carcinogenesis.