Why is checking the special equipment such as vapor recovery kits, hoses, and connectors part of a tank vehicle inspection?

Tank vehicles carry equipment that ordinary trailers do not, and each piece is part of the pre-trip inspection: loading/unloading hoses (no cuts, bulges, or wear), connectors and couplings (tight, no damage), vapor recovery systems where fitted, the manhole covers and their gaskets, and pressure-relief vents. A failure in any of these can let product escape or allow air in that prevents proper draining. Because tank cargo is often hazardous or in large volume, the consequences of a missed defect are severe, so the manual stresses inspecting all tank-specific fittings in addition to the standard vehicle items.