HP codes: hazardous properties (HP1–HP15)
HP codes are the 15 hazardous-property criteria used to decide whether a waste is legally hazardous in the UK. Here's what each one means and what it changes about how the waste must be handled.
HP codes (Hazardous Properties) come from Annex III of the Waste Framework Directive and are applied through the UK Hazardous Waste Regulations, in step with DEFRA's Digital Waste Tracking. They run from explosive and flammable through to ecotoxic and carcinogenic.
A waste only has to exhibit one HP property to be classed as hazardous. At that point it must move on a Hazardous Waste Consignment Note — not a standard Waste Transfer Note — and be carried by a licensed hazardous waste carrier. EWC codes ending in an asterisk (*) flag waste types where HP codes are likely to apply.
The codes carriers hit most often
- HP4Irritant — skin irritation / eye damage
- HP6Acute toxicity
- HP14Ecotoxic
All HP codes (HP1–HP15)
- HP1Explosive
Waste that can explode or undergo a dangerous chemical reaction — e.g. pyrotechnics or self-reactive material.
- HP2Oxidising
Waste that gives off oxygen and so can cause or intensify the combustion of other materials.
- HP3Flammable
Waste that ignites easily — flammable liquids (flash point below 60°C), gases, or solids that ignite through friction.
- HP4Irritant — skin irritation / eye damage
Waste that irritates the skin or damages the eyes on contact. One of the most commonly triggered properties.
- HP5Specific target organ / aspiration toxicity
Specific target organ toxicity or aspiration toxicity — waste that harms specific organs, or is toxic if inhaled or swallowed.
- HP6Acute toxicity
Acute toxicity — waste that can cause severe or fatal effects from a single exposure by ingestion, inhalation or skin contact.
- HP7Carcinogenic
Carcinogenic — waste that can cause cancer or increase its incidence.
- HP8Corrosive
Corrosive — waste that can cause severe skin corrosion or burns on contact.
- HP9Infectious
Infectious — waste containing viable micro-organisms or their toxins known to cause disease in humans or animals.
- HP10Toxic for reproduction
Toxic for reproduction — waste that can harm fertility or the development of an unborn child.
- HP11Mutagenic
Mutagenic — waste that can cause permanent changes (mutations) to genetic material.
- HP12Release of an acute toxic gas
Release of an acute toxic gas — waste that gives off a toxic gas in contact with water, air or an acid.
- HP13Sensitising
Sensitising — waste containing substances that can cause an allergic skin or respiratory reaction.
- HP14Ecotoxic
Ecotoxic — waste that presents a risk to the environment. Very commonly triggered by contaminated soils, solvents and industrial residues.
- HP15Capable of exhibiting a hazardous property not directly displayed
Waste capable of exhibiting a hazardous property (HP1–HP14) that the waste does not directly display itself.
POPs waste, and the code that only exists digitally
Waste holding persistent organic pollutants (POPs) above the limits in Annex IV of the POPs Regulation is hazardous in its own right, whatever the HP assessment says, and it has to be destroyed rather than landfilled or recycled.
- HP_POPContains POPs above the legal limits
Waste containing persistent organic pollutants above the concentration limits in Annex IV of the POPs Regulation, most often flame retardants in upholstered seating and insulating foam. It is hazardous in its own right and must be destroyed, not landfilled or recycled.
That case has its own hazard code in DEFRA's Digital Waste Tracking service. It comes from the POPs Regulation rather than the Waste Framework Directive, so it sits outside the Annex III set above and you won't find it on a paper consignment note. If you record the movement digitally, it's there in the list of properties to tick.
For the full classification method see the official gov.uk waste classification guidance (technical guidance WM3). Always confirm the classification before transferring waste.
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CarrierNote is on the GOV.UK software provider list, connected to DEFRA's Digital Waste Tracking service. Receiving sites are in scope from October 2026 and carriers from October 2027, and you can be recording to DEFRA's standard from your first load, whenever you start.