HP2: Oxidising
Waste which may, generally by providing oxygen, cause or contribute to the combustion of other materials.
What this usually means in practice
HP2 covers wastes that feed combustion rather than necessarily burning first themselves. Oxidising salts, peroxides and similar materials can intensify fires and make mixed wastes more dangerous.
Definition
Exact definition wording taken from WM3 Appendix C / Annex III for this hazardous property.
waste which may, generally by providing oxygen, cause or contribute to the combustion of other materials
What to check when assessing this property
Use the official definition, composition data and waste-process knowledge together. These points are meant to help frame the assessment, not replace WM3.
- Look for oxidising hazard classes or substances that release oxygen and accelerate burning (H270, H271, H272).
- Where a single oxidising substance sits below its GB CLP specific concentration limit (MCL) and no other oxidisers are present, WM3 allows the waste to be treated as not HP2.
- Otherwise use test methods (or the ISO 10156 calculation for oxidising gases) in line with the Guidance on the application of the CLP criteria.
How to use this page
Hazardous properties explain why a waste may be hazardous. They sit alongside EWC classification and they do not replace formal WM3 assessment or site acceptance checks.
1. Start with the waste
Identify the likely EWC entry, the process that produced the waste and whether it is part of a mirror-entry assessment.
2. Check the hazard evidence
Use composition data, SDSs, testing, pH, flash point and process knowledge as relevant to the property in question.
3. Confirm the final outcome
Confirm the conclusion against WM3 and any permit-specific or site-specific acceptance requirements before relying on it.
Wording is based on Annex III of the consolidated Waste Framework Directive opens in a new tab and should be used alongside Waste classification technical guidance (WM3, 3rd edition, 2021) — GOV.UK opens in a new tab.