WM3: classifying a load before you pick the code
WM3 is the technical guidance the UK environment agencies publish on classifying and assessing waste, and it is where a List of Waste code comes from. This page explains what it asks you to do, in the order a yard actually does it, before the code goes on a transfer note.
What WM3 waste classification means
WM3 is the technical guidance the UK environment agencies publish on classifying and assessing waste: it is the document that tells you how to reach a List of Waste code for a load and whether that waste counts as hazardous. Its full name is Waste Classification: Guidance on the Classification and Assessment of Waste, issued jointly for England, Wales, Scotland and Northern Ireland. Nobody in a yard calls it that. They call it WM3.
It matters to a skip yard because a code is not a label you pick from habit. WM3 works forward from the process that produced the waste, into the chapters of the List of Waste, and then to the type of entry you have landed on. An entry is either absolute hazardous, carrying an asterisk, absolute non-hazardous, or one of a mirror pair, where the same material can fall either side depending on what is actually in it.
A load off the weighbridge
A tipper brings in soil from a strip of ground behind an old vehicle workshop. Soil and stones sit on a mirror pair in the List of Waste: one entry for soil containing dangerous substances, one entry for the rest. Nothing on the weighbridge ticket settles it. The answer rests on what the producer knows about the ground, and where that is not enough, on testing what is in it.
Until that is settled the load does not have a code. A note written with the clean entry because it is the one you type most often is a record the yard cannot stand behind later, and it is the kind of record an officer asks about.
How a load gets to a code
- Start with the process, not the skip
WM3 begins with what produced the waste. A strip-out, a groundworks dig and a garage clear-out send you to different chapters of the List of Waste even when the skip looks similar from the top.
- Find the candidate entries
Work the chapter down to the entries that could describe the load. Most yards end up choosing between two or three, not inventing one.
- Read what kind of entry it is
An asterisked entry is hazardous whatever the load looks like. A plain entry is not. A mirror pair means the decision is still open and depends on the substances present.
- Assess a mirror entry properly
For a mirror pair you need enough knowledge of the waste to say which side it falls on, from the producer's knowledge of the process or from analysis. A guess is not an assessment.
- Write the code and the description together
The code and the words that describe the waste go on the transfer note as a pair. If the description says one thing and the code says another, the record contradicts itself.
Where receiving sites get caught
Four things go wrong often enough to be worth naming:
- The asterisk gets dropped. Typed as six digits off a ticket, an absolute hazardous entry can lose its star and read as ordinary waste on the note and in the quarter's figures.
- A mirror entry is treated as absolute. The clean side of the pair becomes the default because it is quicker, and no assessment is ever recorded.
- The description and the code disagree. The waste is written as one thing and coded as another, usually because the code was carried over from the last load.
- Classification is assumed to be somebody else's job. The producer has the duty to classify, but a site that accepts a load on a description that does not match what is in the skip has its own duty of care to answer for. Checking the code at the gate is cheaper than correcting it after the quarter closes.
Related terms
WM3 sits next to several things a yard deals with daily, and each has its own page here:
- EWC code, or List of Waste code. The six-digit code WM3 leads you to, and where it goes on the paperwork.
- The asterisk on an EWC code. What an absolute hazardous entry means and why the star must survive being typed.
- Hazardous waste consignment note. The separate record a hazardous movement needs, which a transfer note does not replace.
- Duty of care. What a receiving site is answerable for when it accepts a load.
- Waste transfer note. The record itself, and the fields it has to contain.
- Mixed construction and demolition waste, and soil and stones. Two code questions a skip yard meets every week, worked through in full.
- Correcting a code before the quarter closes. What to do when the wrong entry is already on a note.
Questions
Is WM3 the law?
No. WM3 is guidance from the environment agencies on how to apply the law. The duties themselves sit in the waste regulations, which is why a classification that departs from WM3 needs a reason you can explain rather than a preference.
Who is supposed to classify the waste, the producer or the receiving site?
Classification is the producer's duty. A receiving site still has its own duty of care, so taking a load on a description and a code that plainly do not match what is in the skip is the site's problem too.
What is a mirror entry?
A pair of List of Waste entries covering the same kind of material, one hazardous and one not, where which applies depends on the dangerous substances present. Soil and stones is the pair most skip yards meet. The decision needs knowledge of the waste, not a preference for the quicker code.
Do I need laboratory testing to classify a load?
Not always. Where the producer knows the process well enough to say what is in the waste, that knowledge can carry the assessment. Where it cannot, for example made ground of unknown history, analysis is how the mirror entry gets settled.
Does WM3 apply outside England?
WM3 is issued jointly by the environment agencies across the UK, so the classification approach is the same in England, Wales, Scotland and Northern Ireland. The permitting and reporting duties around it are administered by each regulator separately.
Where does the code end up once it is decided?
On the transfer note for the movement, and then in the figures for the period when the yard reports its waste. A wrong code therefore shows up twice, which is why most of the cost of getting it wrong lands weeks after the skip has gone.