Which statement about entry into a space that has been sealed for a long time is TRUE?

Correct Answer: Option C — A tank that has been used to carry hazardous liquids should be tested for oxygen content, toxicity, and explosive gases.

Confined spaces, especially those previously containing hazardous liquids, pose severe risks of oxygen deficiency, toxicity, and flammability. Proper safety protocols require comprehensive atmospheric testing for all three conditions before entry. Relying on natural ventilation or visual inspection is insufficient to guarantee a safe environment for personnel entering a sealed space.