HP4: Irritant — skin irritation and eye damage
Waste which on application can cause skin irritation or damage to the eye.
What this usually means in practice
HP4 deals with irritation and eye damage where the waste can inflame skin or harm eyes on contact. It often arises from acidic or alkaline mixtures that are harmful on contact but do not reach the corrosive threshold for HP8.
Definition
Exact definition wording taken from WM3 Appendix C / Annex III for this hazardous property.
waste which on application can cause skin irritation or damage to the eye
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.
- Sum the relevant H314, H315, H318 and H319 components using WM3 rules.
- Check whether the waste remains within irritant classification or crosses into corrosive classification under HP8.
- Use real composition data where possible, because generic descriptions can understate concentrated mixtures.
Supporting points
Additional points shown where the official definition or WM3 guidance breaks the hazard into categories or clarifications.
- H314 Skin Corr. 1A at a total concentration of 1% or more gives HP4, but once H314 substances reach 5% the waste is HP8 instead.
- H318 Eye Dam. 1 gives HP4 at a total concentration of 10% or more.
- The combined total of H315 Skin Irrit. 2 and H319 Eye Irrit. 2 gives HP4 at 20% or more.
Notes
Additional context added where the official wording or WM3 guidance needs a short plain-English explanation.
- Mechanical irritation alone, for example from some mineral wool, is not included within HP4.
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.