When a drum, IBC, or hazardous goods container is damaged, leaking, or compromised in transit or storage, the immediate priority is containment. In many situations, the safest and most legally compliant solution is to place the damaged packaging inside an overpack or salvage drum. These specialist containers are a fundamental part of hazardous materials management in the UK and are specifically addressed under both domestic and international transport regulations.
What is an Overpack?
An overpack is an outer enclosure used to consolidate one or more packages of dangerous goods for ease of handling and transport. The term is formally defined under the ADR (European Agreement Concerning the International Carriage of Dangerous Goods by Road), which is incorporated into UK law through the Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations 2009 (CDG Regulations).
Overpacks are used when the inner packaging remains intact but additional protection or consolidation is required. They are not a substitute for UN-approved packaging and must be clearly marked with the word "OVERPACK" if the UN marks on the inner packages are not visible from outside.
What is a Salvage Drum?
A salvage drum (also called a recovery drum or rescue drum) is a robust, UN-approved container specifically designed to receive damaged, leaking, or non-conforming hazardous goods packaging. Unlike standard drums, salvage drums are built to withstand internal pressure, resist corrosion from a broad range of substances, and provide a secondary seal in the event of further leakage from the inner container.
Salvage drums must themselves carry UN approval markings. Under ADR, the salvage packaging type code is identified by the letter "T" in the UN certification mark (e.g., 1A2T for a steel drum approved for salvage use).
Key Differences: Overpack vs Salvage Drum
| Feature | Overpack | Salvage Drum |
|---|---|---|
| Primary Purpose | Consolidation / outer enclosure for intact packages | Emergency containment for damaged/leaking packages |
| UN Approval Required? | No (inner packages must be UN approved) | Yes — must carry UN salvage drum certification |
| Typical Material | Cardboard, plastic, or steel outer | Heavy-gauge steel or HDPE with gasket lid |
| ADR Reference | ADR 1.2.1, 5.1.2 | ADR 6.1.5.1.11, Packing Instruction P650 |
| Marking Requirement | "OVERPACK" label if UN marks obscured | UN certification mark with "T" suffix |
| Typical Use Case | Air freight consolidation, multi-bottle shipments | Leaking drum in transit, corroded IBC, spill recovery |
When Should You Use a Salvage Drum?
Salvage drums should be deployed whenever a hazardous goods package is found to be:
- Leaking or seeping — even a minor drip requires action under CDG Regulations
- Structurally compromised — dents, corrosion, or damaged closures
- Contaminated externally — where the outer surface poses a direct hazard
- Non-compliant for transport — damaged labelling, missing UN marks, or out-of-date certification
The decision to use a salvage drum should be documented as part of your dangerous goods emergency response procedure. All staff handling ADR shipments should be trained to Vocational Training Certificate (VTC) standard where required by the regulations.
Practical Guidance for Use
When placing a leaking container into a salvage drum, always use appropriate PPE as specified by the substance's Safety Data Sheet. Do not overfill — the salvage drum must be able to be sealed completely. Add absorbent material (compatible with the substance) to the void space to immobilise residual leakage. Ensure the salvage drum is correctly labelled with the inner substance's hazard information before any onward transport.
At Spill Control Products UK, we stock a range of overpacks and salvage drums in UN-approved steel and HDPE construction, suitable for drums up to 210 litres. All products are supplied with relevant UN certification documentation.
Need expert advice? Call 01744 520 110