Question 65

The Correct Answer is A **Explanation for A (70°F):** Regulations governing the safe handling and transportation of hazardous chemicals, particularly gases like ethylene oxide (EO), specify maximum temperatures to prevent potentially dangerous pressure build-up or thermal instability. Ethylene oxide is a highly reactive and flammable chemical. Regulatory bodies, such as the US Coast Guard (under 46 CFR, specific codes for chemical tankers and bulk loading) or equivalent international standards (like the IMO IBC Code), typically require that ethylene oxide be loaded and maintained below 21°C (which is approximately $70^{\circ} \mathrm{F}$) during bulk marine transportation to minimize the risk of polymerization and maintain cargo stability. **Explanation for B (its flash point):** Ethylene oxide has an extremely low flash point (approximately $-4^{\circ} \mathrm{F}$ or $-20^{\circ} \mathrm{C}$). While keeping any flammable material below its flash point is a standard safety measure, the $70^{\circ} \mathrm{F}$ limit for EO is mandated specifically to control polymerization and pressure, which is a higher temperature constraint than merely staying below its flash point. **Explanation for C (51°F):** $51^{\circ} \mathrm{F}$ (or $10.6^{\circ} \mathrm{C}$) is significantly lower than the required maximum loading temperature of $70^{\circ} \mathrm{F}$. While loading below $51^{\circ} \mathrm{F}$ would certainly be safe, it is not the mandated regulatory maximum threshold. $51^{\circ} \mathrm{F}$ is sometimes relevant to other properties, but $70^{\circ} \mathrm{F}$ is the loading temperature limit specified in regulations. **Explanation for D (90°F):** $90^{\circ} \mathrm{F}$ is well above the regulatory limit of $70^{\circ} \mathrm{F}$. Loading ethylene oxide at $90^{\circ} \mathrm{F}$ would violate safety regulations and significantly increase the risk of thermal runaway, polymerization, and excessive pressure within the containment vessel.