Atanu joins Rob Mitkus, a PhD toxicologist with 25 years’ experience across pesticides, industrial chemicals, vaccine components, medical devices, and consumer products, to discuss how toxicology underpins Safety Data Sheets (SDS) and HazCom/GHS compliance. Rob defines toxicity as harm under specific conditions and emphasizes SDS content and precautions should be evidence-driven and understandable to downstream users including workers, consumers, and first responders. They discuss reliance on animal “sentinel species,” the rise of new approach methodologies (in vitro, in silico, machine learning), and validation/acceptance via bodies such as OECD and ICCVAM, noting limits for complex endpoints like carcinogenicity and reproductive toxicity. Rob critiques GHS concepts like “intrinsic toxicity,” the definition of sensitization, and hazard-only/binary classifications, stressing dose-response and exposure. He highlights the psychology of threat perception from pictograms and calls for better training and toxicologist involvement in future standards.