Cyanide and Acid on the Same Flatbed
At a fertilizer and pool-chemical distributor near Macon, you are loading a 48-foot flatbed with 20 fiberboard boxes of UN1689, sodium cyanide, 6.1, PG I, each gross 50 lb, and 30 plastic drums of UN1789, hydrochloric acid, 8, PG II, each gross 60 lb. The shipper's load sheet says the acid drums can go on the front half and the cyanide boxes on the rear half because 'the trailer is long enough.' The total gross weight of the acid is 1,800 lb; the cyanide is 1,000 lb. Both shipments have proper labels and shipping papers. The weather is dry, and the trailer has no bulkheads or separate compartments. A loader tells you the last driver took the same combination without a problem.
1. What placards are required for this combination?
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Two different placarding triggers apply. Sodium cyanide, 6.1, PG I, is a Table 1 material, so a POISON placard is required for any quantity; 1,000 lb is more than enough. Hydrochloric acid, Class 8, is Table 2; 1,800 lb exceeds the 1,001-lb Table 2 threshold, so a CORROSIVE placard is also required. The cyanide does not count toward the Table 2 aggregate because it is Table 1, but the acid alone triggers the corrosive placard. Both packages also need the correct 6.1 and 8 labels. Placards do not make the load legal; the segregation prohibition still controls.
2. May you load the cyanide and acid in the same trailer if they are separated front to rear?
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Do not load them together in the same transport vehicle. The segregation rule specifically prohibits loading or storing cyanides or cyanide mixtures with acids. Putting the acid on the front half and cyanide on the rear half of a 48-foot flatbed does not cure the prohibition, because they are still in the same vehicle and a leak or spill could mix them. Acid contact with cyanide can generate hydrogen cyanide, a highly toxic gas. The correct action is to refuse that combination, notify the shipper and your dispatcher, and arrange separate vehicles or separate trips. The fact that a previous driver did it is not a defense; you are responsible for the load you accept.