Toxic Industrial Chemicals (TICs) are chemical substances manufactured, stored, transported or used in large quantities for industrial, agricultural, medical and commercial purposes that can cause serious illness or death when released into the environment. Unlike chemical warfare agents, TICs are generally produced for legitimate civilian and industrial purposes, but their accidental release, deliberate misuse or transportation-related leakage can create a Chemical, Biological, Radiological and Nuclear (CBRN) emergency. Their effects depend on intrinsic toxicity, concentration, duration of exposure, route of entry and physical properties such as volatility and persistence. TICs may be broadly classified according to their toxicity into highly toxic, moderately toxic and relatively low-toxicity chemicals. This classification is primarily concerned with the ability of a chemical to produce harmful or fatal effects at comparatively low concentrations. There is no single universal toxicity boundary applicable to every TIC; occupational exposure limits, Immediately Dangerous to Life or Health (IDLH) values, lethal concentration data and clinical effects are considered when assessing their hazards. Highly toxic TICs are capable of producing severe physiological effects or death following exposure to relatively small concentrations, particularly through inhalation. They are therefore of major concern in CBRN incidents. Phosgene is an important example. It is a highly toxic industrial gas used in the manufacture of plastics, dyes, pesticides and other chemicals. It is heavier than air and can accumulate in low-lying or poorly ventilated areas. Phosgene is particularly dangerous because its initial symptoms may be mild or delayed. Affected individuals may experience irritation, coughing and chest discomfort followed by progressive pulmonary edema and respiratory failure. The latent period can make victims underestimate the seriousness of exposure. In a CBRN event involving phosgene, rapid recognition, removal from exposure, decontamination when appropriate and urgent medical observation are essential. Oxygen therapy and respiratory support may be required in severe cases. The possibility of delayed pulmonary injury means that apparently stable exposed persons may still require medical monitoring. Another important highly toxic TIC is hydrogen cyanide. It interferes with cellular oxygen utilization and can rapidly produce neurological and cardiovascular effects. Severe poisoning may result in seizures, loss of consciousness, cardiovascular collapse and death. Its rapid action makes early recognition and treatment particularly important. Specific antidotal therapy may be required according to established medical protocols, together with supportive management. Moderately toxic TICs generally require greater exposure concentrations or longer exposure periods than highly toxic chemicals to produce severe poisoning, although they can still cause substantial morbidity and mortality during major releases. Ammonia is a useful example. It is extensively used in fertilizer production, refrigeration and various industrial processes. Ammonia is highly irritating to the eyes, skin and respiratory tract. Exposure can cause burning, coughing, bronchospasm, breathing difficulty and, in severe cases, pulmonary edema and respiratory failure. A large ammonia release can therefore create a significant mass-casualty situation, particularly in enclosed or densely populated environments. The importance of moderately toxic