Question 36Safety & Environmental - Assistant Engineer

The correct answer is D) nearly calm, clear nights or early morning. Hydrogen sulfide (H2S) is a dense, toxic gas that can accumulate in low-lying, calm areas, especially during clear nights or early mornings when air temperatures are lower and there is minimal wind to disperse the gas. Under these nearly calm conditions, H2S is less likely to be dispersed and can reach dangerous concentrations. The other options are incorrect because gusty winds with rain (A), heavy rain (B), and full sun with high winds (C) would all tend to increase the dispersion and dilution of the H2S, making it less likely to accumulate to hazardous levels.