Hazardous property code
HP 4 Irritant
Waste that can cause skin irritation or damage to the eyes upon contact.
HP 4 covers waste that causes skin irritation or eye damage on contact. It is a contact hazard rather than a systemic one, which is what separates it from the toxicity properties it often appears alongside.
It is recorded as a hazard code on the consignment note, and it is assigned from the substances present in the load and their concentrations rather than from the waste's EWC entry.
- Code
- HP 4
- DEFRA code
- HP_4
Sourced from DEFRA’s digital waste tracking reference data, last checked 25 July 2026.
EWC codes that commonly carry this hazard property
15 of 44 entries from the UK List of Wastes.
These are EWC entries that typically carry this hazard property, not a determination that any particular load does. Under WM3, whether a hazard property applies depends on the substances actually present and their concentrations — the producer is responsible for assessing each consignment.
- 05 01 04acid alkyl sludgeshazardousAcid alkyl sludges — strongly acidic refinery residue; irritant, corrosive and ecotoxic.
- 05 01 07acid tarshazardousAcid tars — corrosive, irritant, carcinogenic (PAHs) and ecotoxic.
- 05 01 11wastes from cleaning of fuels with baseshazardousWastes from cleaning fuels with bases — corrosive caustic residue; irritant and ecotoxic.
- 05 06 01acid tarshazardousAcid tars (coal coking) — corrosive, irritant, carcinogenic (PAHs) and ecotoxic.
- 06 01 01sulphuric acid and sulphurous acidhazardousSulphuric / sulphurous acid — corrosive and irritant.
- 06 01 02hydrochloric acidhazardousHydrochloric acid — corrosive, irritant and STOT (respiratory tract from HCl mist).
- 06 01 03hydrofluoric acidhazardousHydrofluoric acid — acutely toxic (systemic fluoride), corrosive and irritant.
- 06 01 04phosphoric and phosphorous acidhazardousPhosphoric / phosphorous acid — corrosive and irritant.
- 06 01 05nitric acid and nitrous acidhazardousNitric / nitrous acid — oxidising, corrosive and irritant.
- 06 01 06other acidshazardousOther acids — corrosive and irritant by default.
- 06 02 01calcium hydroxidehazardousCalcium hydroxide — corrosive and irritant.
- 06 02 03ammonium hydroxidehazardousAmmonium hydroxide — corrosive, irritant, STOT (respiratory) and aquatic ecotoxic.
- 06 02 04sodium and potassium hydroxidehazardousSodium / potassium hydroxide — corrosive and irritant.
- 06 02 05other baseshazardousOther bases — corrosive and irritant by default.
- 06 07 04solutions and acids, for example contact acidhazardousContact / process acids (sulphuric acid manufacture) — corrosive and irritant.
Related
Recording HP 4 on real paperwork?
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