What Waste Code

Hazardous waste reference

Hazardous Properties (HP1 to HP15)

Hazardous properties explain why a waste may be hazardous. Use this page to understand what each HP code means, then confirm the final classification using current WM3 guidance and any permit-specific requirements.

Each property page includes the official wording, a plain-English interpretation and practical points to check during a waste assessment. That makes this section more useful for mirror-entry reviews, internal compliance checks and conversations with treatment sites.

Browse all hazardous properties

Use the full set below to move between HP1 and HP15. Each page includes the official definition, a plain-English explanation and practical assessment prompts.

HP1

Explosive

Waste which is capable by chemical reaction of producing gas at such a temperature and pressure and at such a speed as to cause damage to the surroundings.
HP2

Oxidising

Waste which may, generally by providing oxygen, cause or contribute to the combustion of other materials.
HP3

Flammable

Waste which is flammable, including the categories listed below.
HP4

Irritant — skin irritation and eye damage

Waste which on application can cause skin irritation or damage to the eye.
HP5

Specific target organ toxicity (STOT) / aspiration toxicity

Waste which can cause specific target organ toxicity either from a single or repeated exposure, or which causes acute toxic effects following aspiration.
HP6

Acute toxicity

Waste which can cause acute toxic effects following oral or dermal administration, or inhalation exposure.
HP7

Carcinogenic

Waste which induces cancer or increases its incidence.
HP8

Corrosive

Waste which on application can cause skin corrosion.
HP9

Infectious

Waste containing viable micro-organisms or their toxins which are known or reliably believed to cause disease in humans or other living organisms.
HP10

Toxic for reproduction

Waste which has adverse effects on sexual function and fertility in adult males and females, as well as developmental toxicity in the offspring.
HP11

Mutagenic

Waste which may cause a mutation, that is a permanent change in the amount or structure of the genetic material in a cell.
HP12

Release of an acute toxic gas

Waste which releases acute toxic gases (Acute Tox. 1, 2 or 3) in contact with water or an acid.
HP13

Sensitising

Waste which contains one or more substances known to cause sensitising effects to the skin or the respiratory organs.
HP14

Ecotoxic

Waste which presents or may present immediate or delayed risks for one or more sectors of the environment.
HP15

Waste capable of exhibiting a hazardous property not directly displayed by the original waste

Waste capable of exhibiting a hazardous property listed above not directly displayed by the original waste.

How these pages help

Wording is based on Annex III of the Waste Framework Directive and WM3 Technical Guidance (1st edition, v1.2.GB, October 2021). Use these pages as a quick reference only, and confirm classification against the latest UK guidance before relying on it.

What you will find

  • Official Annex III / WM3 wording for each hazardous property.
  • Plain-English context to make the property easier to interpret in day-to-day work.
  • Assessment focus points to help frame what evidence to check next.

What these pages do not do

  • They do not replace a full WM3 classification exercise.
  • They do not choose the final EWC code for you without supporting evidence.
  • They do not confirm whether a specific treatment site will accept the waste.

Principles for using hazardous properties

Keep these points in mind whenever you are mapping a waste stream to one or more HP codes.

Use HP codes to explain risk

Hazardous properties describe the characteristic that makes the waste hazardous. They do not replace the EWC catalogue entry.

Check evidence, not labels

Use SDSs, composition data, process knowledge and testing where relevant. Generic names alone are rarely enough to support a sound assessment.

Keep site acceptance separate

A hazardous-property outcome helps with classification, but it does not guarantee that a given site can accept the waste.