A corrosive waste declared only as a flammable liquid
A tank-wagon arrives at a rail terminal loaded with liquid waste from a metal-treatment plant. The consignment note describes it as “UN 1993 FLAMMABLE LIQUID, N.O.S. (contains hydrochloric acid and organic solvent), 3, II, 24,000 L”. The safety data sheet gives a flash point of 18 °C, pH 1.2, severe skin burns and attacks of mild steel. The tank-wagon is mild steel, has only a Class 3 label, and its last internal inspection was four years ago. The consignor says the acid is “only an impurity” and that the flash point determines the class. The train is due to leave in two hours. The tank-wagon has no lining certificate on file. The terminal has no other suitable tank-wagon available today.
1. Evaluate the classification and proper shipping name. Is UN 1993 correct?
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UN 1993 is not correct. The flash point of 18 °C brings the liquid within Class 3, PG II, but classification is not decided by flash point alone. A pH of 1.2 and severe skin burns mean the substance also meets the Class 8 corrosive criteria. For a flammable liquid that is also corrosive, the proper shipping name is UN 2924 FLAMMABLE LIQUID, CORROSIVE, N.O.S., Class 3, subsidiary risk Class 8, PG II, with the technical name in brackets.
The consignor has selected a proper shipping name that recognises only the flammability hazard and has omitted the corrosive subsidiary risk. Describing the acid as an impurity does not remove the hazard: the mixture as offered meets the Class 8 criteria. The classification and the dangerous goods description must be corrected before carriage.
2. What labels, placards and tank-wagon properties are required, and can this tank-wagon be used?
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The packages or tank-wagon must display the Class 3 label or placard and the Class 8 subsidiary label or placard. The wagon must carry the required placards on both sides, and the documents must show UN 2924, the proper shipping name with technical name, Class 3, subsidiary Class 8, and PG II.
This tank-wagon should not be used. Hydrochloric acid attacks mild steel, so a mild-steel tank without a verified lining is not suitable for the load. The absence of a lining certificate means suitability cannot be demonstrated. The last internal inspection being four years ago is a separate concern: the tank must be within its inspection regime and the certificate must be available. The consignor’s argument that the acid is only an impurity does not make mild steel compatible. Reject the wagon and require a suitable lined or otherwise resistant tank-wagon with valid certification.
3. What action should the terminal and DGSA take before departure?
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The terminal should stop the movement, keep the wagon isolated and notify the consignor that the load is rejected pending reclassification and a suitable tank-wagon. The consignment note must be rewritten with UN 2924, the correct proper shipping name and subsidiary risk, and the tank-wagon must be replaced or verified as compatible and in date. Labels and placards must be corrected. Emergency information must match the corrected classification and be available to the train crew.
As DGSA, record the finding, the reason for rejection and the corrective action requested. Check whether the same consignor has other tank-wagons in the terminal. Report the matter to management as a compliance failure and follow up until the corrected documents and tank-wagon are verified. Do not allow the train to depart on the basis of a verbal assurance that the acid is “only an impurity”.