Unloading Drums at a Farm Supply
You arrive at a farm supply store with a mixed load: 20 drums of UN1789 Hydrochloric acid, 8, PG II; 10 drums of UN1824 Sodium hydroxide solution, 8, PG II; and 15 bags of UN1479 Oxidizing solid, n.o.s., 5.1, PG III. The receiving dock is a gravel lot with a slight slope. The store's forklift is broken, so the clerk wants you to roll the drums down a ramp by hand and stack the acid drums next to the caustic drums against the back wall of the dock. It is 95 degrees and the drums have been in the sun. The clerk says the acid and caustic 'don't react, they just neutralize,' and that the oxidizer bags can go on top of the acid drums to save space.
1. Evaluate the proposed loading and unloading plan for segregation and compatibility problems.
Read the worked answer
The plan has multiple problems. First, hydrochloric acid (Class 8, PG II) and sodium hydroxide solution (Class 8, PG II) are both corrosive, and although they neutralize each other, the reaction is highly exothermic and can produce heat, spattering, and hazardous fumes; they should not be stored or stacked in contact where a leak could bring them together. Keep them separated and, if possible, in separate containment areas. Second, the oxidizer (Class 5.1) must be segregated from acids and from combustible materials. Placing oxidizer bags on top of acid drums is exactly backwards: a leak of acid onto the oxidizer, or a rupture of a drum under the bags, could create a violent reaction. Oxidizers should be kept away from acids, caustics, and organic materials. Third, the gravel lot with a slope is a poor unloading surface: rolling drums by hand down a ramp on gravel risks a drum tipping, rupturing, and releasing acid or caustic. Use a drum truck or pallet jack on a stable surface, or ask the consignee to provide mechanical means. Fourth, the heat matters: drums in direct sun can build pressure, and a corrosive under pressure can spray when opened. Let them cool, and vent or open only per the shipper's instructions. Fifth, the clerk's 'they just neutralize' reasoning is unsafe because neutralization is still a chemical reaction with heat and fumes. The correct approach is to refuse the stacking arrangement, separate the classes, use mechanical handling, and document the consignee's refusal to provide safe equipment.
2. What must you confirm before you leave the shipment, and what if the consignee refuses to accept the load?
Read the worked answer
Before leaving, confirm that the consignee has received the shipping paper, that the packages are marked and labeled correctly, and that the receiving area is safe for the material. Check that the acid and caustic are not stored together, that the oxidizer is segregated, and that the dock has containment or at least a way to keep spills out of drains. If the consignee refuses the load, you must not simply abandon it. You should notify your carrier and the shipper, keep the material secured on the vehicle or in a safe holding area, and follow the carrier's instructions for returning it or taking it to an approved facility. Do not leave hazardous materials unattended in an unsecured area. If the consignee will accept only part of the load, get the refusal in writing, note the condition of the packages, and make sure the shipping paper reflects what was actually delivered. If a drum is damaged, do not accept it back onto the truck without containment and proper packaging; treat it as a spill and follow the emergency response information on the paper.