Mirror entries in waste classification explained

By WasteSignal · England, Scotland and Wales

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Mirror entries are linked waste classification entries that require assessment to decide which entry applies. They include hazardous and non-hazardous alternatives. The choice depends on the waste and the assessment required by the entries, not on which code a nearby facility prefers to receive.

If you encounter a mirror entry during a supplier enquiry, gather information about the waste’s origin and composition and involve a competent assessor where needed. You can organise much of that information yourself, even when the technical classification decision needs specialist help.

The sites and waste types pillar guide explains the relationship between classification and destination research. For the broader starting point, read how to identify hazardous waste.

How do mirror entries work in the List of Wastes?

The regulators’ WM3 technical guidance explains entry types and the assessment process. Some waste entries are absolute hazardous or absolute non-hazardous; others are mirror entries. Read the full entry descriptions and relevant notes, since linked entries are not always a simple adjacent pair.

A hazardous waste code has an asterisk. That symbol alone does not tell you whether the entry is absolute hazardous or mirror hazardous. Identify the entry type in WM3 and consider the relevant linked entries before deciding what assessment is needed.

Mirror entries can refer generally to hazardous substances or specifically to a substance or property. That wording changes the assessment enquiry. A competent assessor should identify the applicable entry and explain the basis of the decision, including relevant hazardous properties and persistent organic pollutants where required.

For your own research record, keep the full description with the code. A six-digit number copied into a spreadsheet loses useful context if nobody can see the producing activity or entry wording. Our guide to using waste codes in research explains how to use the resulting classification when looking for an outlet.

Why does the waste’s source matter before choosing a code?

Describe the activity that produced the waste and what happened to it afterwards. A material name alone may leave several possible entries. “Sludge” gives an assessor less information than an explanation of the process, inputs and treatment that produced the sludge.

Gather the process information from people who know it. Ask the production team what raw materials entered the process, whether cleaning chemicals or additives were used and whether the waste has been mixed or stored with other material. Do not assume the purchasing description of the original product still describes the waste after use.

For a clearance, identify whether the material comes from one consistent source or several unrelated areas. A container assembled over time can include components with different histories. Tell the assessor what is known and what remains uncertain so that the scope of the enquiry reflects the actual material.

Keep boundaries clear. If an assessment covers one batch or one defined production stream, record that scope. A useful report should not become a general approval for every similar-looking material across your business. Ask whether another source or changed process needs separate consideration.

What information should you give a waste classification assessor?

Begin with a written account of the waste, its origin and the question you need resolved. Attach relevant process records, product information and previous analysis. Explain the proposed quantity and whether it is a one-off batch or a continuing stream. Label estimated and measured information separately.

A useful enquiry pack can include:

The producing activity and location, with a description of the material’s physical form.
Known ingredients, contamination and relevant changes during use or storage.
Current product or safety information where it genuinely describes the material.
Existing sampling plans and laboratory reports, including their dates and sample locations.
The boundaries of the waste being assessed and any variability within it.
The proposed movement date, so that the assessor understands when a decision is needed.

Ask the assessor to identify gaps before commissioning additional analysis. A laboratory needs a suitable testing request, and a generic package may not address every relevant substance or property. Our guide to waste testing and sampling explains how to organise that conversation.

Maintain an enquiry log when several people supply information. Record who confirmed the process history and which documents describe the current stream. If you discover a mistake, pass the correction to the assessor promptly. Preserve the earlier version with a clear explanation so that the final assessment is based on the right information.

Does every mirror entry require laboratory testing?

The evidence needed depends on the waste and what is already known. Ask the assessor whether reliable composition and process information can answer the relevant questions or whether sampling and analysis are necessary. Avoid treating a test request as an automatic requirement for every waste solely because a mirror entry is involved.

Equally, do not use an absence of testing as evidence of non-hazardous status. Ask what supports the classification. A report may rely on suitable information from a consistent process, while another waste needs investigation because its history or composition is uncertain.

If testing is required, define what the sample represents. Material from one corner of a stockpile may not answer a question about the whole pile. Ask the competent person planning the assessment how to address variability and whether separate batches should remain separate for assessment.

Keep the purpose of each analysis clear. A test requested by a particular outlet can answer an acceptance question without completing classification. Our guide to WAC testing and waste classification explains why landfill acceptance results and classification should not be used interchangeably.

Can a safety data sheet settle a mirror-entry assessment?

Provide relevant safety data sheets to the assessor, but explain how the product was used. A current sheet for an unused product may help describe its original composition. It may leave out changes caused by a process, contamination or mixing after use.

Match each sheet to the material in question. A brand can have several formulations, and a sheet for a replacement product may differ from the one originally used. Note the product identification and document date, and tell the assessor if the exact match cannot be established.

For residues from several products, describe how they arose and whether they were combined. Do not select the most convenient sheet and assume it covers the entire waste. If a supplier can provide additional technical information, ask for it through the assessor’s specific enquiry.

Keep a plain-language account of the assumptions. For example, a report might depend on a particular product being the only input to an unchanged process. Staff responsible for that process need to know that a substitute product could require reassessment. This is a practical way to keep a technically sound decision connected to day-to-day operations.

What if the composition is unknown?

Ask what investigation can establish it. Look for purchasing records, process information, previous occupier information or other relevant evidence before concluding that the composition cannot be determined. Tell the assessor about limits in the records and any reason to suspect additional constituents.

WM3 explains that where a mirror-entry waste’s composition is unknown and genuinely cannot be determined, the hazardous mirror entry must be used. A competent assessment should address that position; an unsupported non-hazardous description is unsuitable simply because the business wants an ordinary collection route.

Keep uncertain waste secure and avoid adding other material while the assessment is underway. Ask competent people about the storage and handling arrangements appropriate to the circumstances. Do not open unidentified containers or disturb potentially hazardous material merely to obtain a photograph for an enquiry.

If the decision remains unresolved near the planned collection date, tell the organiser what information is missing. Adjust the booking or obtain a checked route suitable for the properly assessed waste. Commercial urgency cannot supply the evidence needed to select the non-hazardous alternative.

Can a receiving facility choose the mirror code for you?

A facility can provide useful technical input and may offer a classification service. Ask who carries out the assessment, what information they need and what written outcome they will provide. The producer should understand and retain the basis of the description used for the transfer.

Separate technical assessment from the facility’s commercial acceptance decision. A statement that “we only take the non-hazardous code” describes a restriction on the outlet. It does not establish that your waste meets that entry. Use the completed classification to find a suitable facility.

Ask about any disagreement in writing. If your assessor and the facility propose different descriptions, give each the relevant evidence and request a reasoned explanation. A short conversation between competent people may identify a wrong assumption about the source, a different batch or a missing report.

Our guide to permitted waste codes and acceptance explains the next step. Even a correctly classified non-hazardous waste may be unsuitable for a particular facility because of its activity, conditions, composition or current acceptance arrangements.

How should you read a mirror-entry assessment report?

Check that the report identifies the actual waste and the material boundaries. Look for the source, relevant samples or information, entry considered and final code with its description. Ask for clarification if the conclusion appears to concern a different site, process or batch.

Read limitations and assumptions before using the result. A report based on a defined set of inputs may not cover a later change. A laboratory result showing a substance below its reporting limit still needs suitable interpretation within the assessment; avoid translating a table into a classification yourself.

Ask the assessor to explain what the outcome means for handling and destination enquiries. The person booking the collection needs an accurate description and relevant hazards, while the technical file can retain the detailed reasoning. Ensure the summary does not remove a condition that affects how the waste must be managed.

For a fictional example, a business commissions an assessment of residue from a named manufacturing process. The report describes the process inputs and the assessed batch. A later maintenance clearance adds unrelated residues to another container. The business asks whether the original assessment covers the new material before reusing its code on the next collection.

What changes should prompt you to review the assessment?

Choose review triggers around the assumptions in the report. A change in raw materials, process chemistry, storage history or contamination can affect whether the earlier assessment remains representative. Tell the assessor what changed and ask what further work is required.

For excavation or clearance work, a different area can have a different history even when the material looks similar. Keep the location and batch information with the assessment. Our guide to waste soil and stones destinations discusses the information needed for those enquiries.

If a receiving operator reports a discrepancy, investigate the actual difference. Ask whether it concerns classification, the physical condition of the load or another acceptance restriction. Update the description where evidence requires it and retain the reason for the correction.

Avoid presenting an internal annual review date as a statutory expiry for every classification report. What matters operationally is whether the assessment still describes the waste and meets applicable requirements. Set a process for notifying changes so that the people producing the waste can prompt a review before dispatch.

How do classification, POPs and national rules fit together?

Hazardous classification and restrictions on waste containing persistent organic pollutants need their relevant assessment. Ask the competent assessor about current POPs requirements where the material raises that question. Our guide to POPs waste and upholstered seating explains a common destination enquiry without treating POPs and hazardous status as interchangeable labels.

Use the current GB WM3 guidance and follow the movement rules for the jurisdiction involved. Scotland uses the term special waste in its regulatory arrangements. The Scottish duty of care code explains responsibilities for Scottish waste holders; cross-border movements need the applicable procedures checked.

Classification does not authorise a receiving activity. Identify the operator and current permission separately, using operator checks. For Scottish facilities, consult SEPA’s transition information when legacy records or descriptions need clarification.

In England and Wales, section 3.2 of the duty of care code requires withholding waste where you suspect an inappropriate permit or exemption, or a breach of its conditions, and advises reporting suspected illegal activity or breaches. Resolve such concerns before relying on a proposed destination.

What should you give the collection organiser?

Provide the assessed code and full waste description, the relevant hazards and preparation instructions, and the receiving site’s written acceptance conditions. Identify the assessment reference so that a technical question can reach the right person quickly. Do not expect a driver to reconstruct the assessment from raw laboratory tables.

Tell the organiser what would invalidate the current arrangement. That might include additional waste in the container, a different source batch or a proposed destination that has not assessed the material. Give them a named contact and a clear instruction to raise such changes before loading.

Keep technical evidence and movement records connected in the filing system. A future reviewer should be able to see which assessment supported a particular description and which acceptance decision related to it. Preserve corrections with their dates rather than overwriting the history.

After collection, review any feedback from the facility. A rejection or revised description may reveal a problem with the enquiry information or material segregation. Record the corrective action and tell the producing team what they need to do differently before the next batch arises.

What are mirror entries in waste classification?