Chlorine gas hazard depends on exposure concentrations. Which statement is true?

• A. False—chlorine is TIH only at high pressure
• B. True
• C. False—chlorine never TIH
• D. Not enough data

Answer: (B)

Chlorine’s danger is driven by how concentrated the gas is in the air and how long someone is exposed. As concentration increases, the health effects become more severe—from eye and airway irritation at lower levels to potentially fatal lung injury at higher levels. Its status as a toxic inhalation hazard isn’t determined by pressure; it’s about dose and exposure duration. Chlorine also behaves as a dense gas, so it can accumulate in low-lying or poorly ventilated areas, raising exposure risk. Because of these concentration- and exposure-dependent effects, the statement that the hazard depends on exposure concentrations is true.