Which tank carrier is designed to haul various chemicals whose pressures DO NOT exceed 40 PSI?

• A. MC 307/DOT 407
• B. MC 331/DOT 111
• C. MC 306/DOT 406
• D. MC 312/DOT 412

Answer: (A)

This tests understanding of tank-car pressure ratings. Low‑pressure, non‑pressurized cargo tanks are built to keep internal pressure at or below about 40 psi, making them suitable for many chemicals whose vapor pressure won’t push the vessel above that limit. The MC 307/DOT 407 design is specifically for these kinds of spills where pressure remains under 40 psi.

The other tank types are designed for higher pressures or for specialized contents—one is for high‑pressure gases, and the remaining designs are intended for different chemical services with pressures that exceed or differ from the 40‑psi limit. So the tank carrier intended for chemicals whose pressures do not exceed 40 psi is the MC 307/DOT 407 type.