Question 135Safety & Environmental - QMED

The correct answer is B) Petroleum vapors are dangerous at all times due to their toxicity. Petroleum vapors are dangerous at all times because they are toxic, regardless of the oxygen concentration, the vapor source temperature, or the vapor concentration being within the explosive limits. Petroleum vapors can cause various health issues, including respiratory problems, dizziness, and even unconsciousness, even at low concentrations. Therefore, the correct answer is that petroleum vapors are dangerous at all times due to their toxicity, not just under specific conditions. The other answer choices are incorrect because they do not fully account for the hazardous nature of petroleum vapors. Oxygen concentration, flash point, and explosive limits are important factors, but they do not determine the overall danger posed by the toxicity of the vapors.