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.
What this usually means in practice
HP9 is the infection category and is different from the chemistry-based HP codes. It applies where viable micro-organisms or their toxins can cause disease and where special handling is needed to prevent infection.
Definition
Exact definition wording taken from WM3 Appendix C / Annex III for this hazardous property.
waste containing viable micro-organisms or their toxins which are known or reliably believed to cause disease in man or other living organisms.
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.
- Use sector-specific healthcare, veterinary or biosecurity guidance rather than Annex III concentration sums.
- Check whether the waste is subject to special collection, packaging or disposal controls because of infection risk.
- Separate infectious risk from unpleasant or putrescible waste, because contamination with pathogens is the key issue.
Supporting points
Additional points shown where the official definition or WM3 guidance breaks the hazard into categories or clarifications.
- HP9 is not assessed by chemical concentration limits; it depends on whether viable micro-organisms or their toxins can cause disease.
- WM3 says attribution of HP9 is assessed under reference documents or legislation in the relevant state rather than Annex III concentration tables.
- For healthcare waste, the key question is whether collection and disposal are subject to special requirements in order to prevent infection.
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.