Toxic exposures, especially gases, are important to understand in order to properly manage both commonplace exposures and mass casualty events. Irritant gases such as chlorine are common in our society, and recognition of the relationship between water solubility and the nature of symptoms is important for predicting symptoms and outcomes. Cyanide is a metabolic toxin with antidotal choices requiring understanding of their mechanisms of action to select appropriate, safe therapy. The effects of carbon monoxide, one of the more commonly encountered gas toxins, can be insidious; diagnosis and therapy are not always straightforward. Although exposure to blister/vesicant agents is rarely seen, the potential for serious harm to both the victim and the secondarily exposed caregiver is significant.