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Recording a POPs or hazardous concentration you only know as a limit

7 November 2026 · CarrierNote

Sometimes the only thing you know about a chemical in a load is which side of a limit it sits. A test or the producer tells you the flame retardants in some sofa foam are "above 500mg/kg", and that's all you get. DEFRA (the Department for Environment, Food and Rural Affairs) has added a way to record that on Digital Waste Tracking. You give the limit as the figure and mark it as "above" or "below", so the record says what you know and no more.

The two kinds of waste work differently. A POPs chemical can be recorded as above or below a limit. A hazardous component can only be recorded as above one. Either way, you still give the figure, and DEFRA reads it as the limit. You can record a receipt this way now.

Who this applies to

Digital Waste Tracking is DEFRA's online service for recording waste movements. Since October 2026, receiving sites in England and Wales have recorded every load they take in on it. For each load the site makes a receipt, the record of what arrived. Our post on what changes for receiving sites covers the rest of it.

This post matters to you if your site takes in POPs waste or hazardous waste. POPs (persistent organic pollutants) are chemicals that don't break down in the environment, such as the flame retardants found in old upholstered seating. Hazardous waste is waste with properties that make it harmful, such as being toxic or flammable.

What a receipt asks for

GOV.UK's guidance for receiving sites sets out what goes on the receipt. If a load holds a chemical from the POPs list, you enter the chemical's name and its concentration. For hazardous waste you enter each chemical or biological component and its concentration. In both cases, if you can't give the information, you must state why.

A concentration is how much of the chemical is in the waste, usually given in mg/kg (milligrams of the chemical in every kilogram of waste). Our posts on POPs and hazardous waste consignment notes explain where those figures usually come from, and our POPs guide lists the code for each POPs chemical.

Why you might only have a limit

An exact figure needs a measurement, and plenty of loads arrive without one. The producer may know their waste is over a limit without knowing by how much. A test may tell you only that a result passed or failed.

Even a lab figure can be shaky. The Environment Agency warns that a lab test can badly underestimate the POPs in some materials, giving the flame retardants in plastic as its example. So "above 500mg/kg" can be the most honest thing you can say about a load.

The limits themselves are set in law. For the five flame retardants common in upholstered seating, counted together, the POPs limit is 500mg/kg. For many other POPs chemicals it's 50mg/kg. Waste at or above the limit is POPs waste, and its POPs have to be destroyed.

How a limit is recorded

DEFRA's published description of the service shows how it works. Each POPs chemical or hazardous component already carries a concentration. Beside it there's now an optional marker that turns the figure into a limit:

  • POPs can be marked "above" (written ">") or "below" (written "<").
  • Hazardous components can be marked "above" only.
  • With either marker, the figure is still required. It has to be a number above zero, and DEFRA reads it as the limit.

So a sofa load with flame retardants over the limit goes in as "> 500mg/kg". A test that showed them under it goes in as "< 500mg/kg".

The "above only" rule for hazardous waste is deliberate. DEFRA's code notes that regulators accept "above" or "below" for POPs but only "above" for hazardous waste.

The figure stays required because a marker on its own tells the regulator nothing. "Above" means nothing until you say above what.

Why you shouldn't write the limit as the figure

Before this marker existed, the only box was the concentration itself. The tempting shortcut was to type the limit, say 500, as if it were a measurement.

That record says the load held 500mg/kg, which nobody measured. You keep the record for years, and it's what the regulator reads if a load is ever questioned. If the true figure was 4,000mg/kg, the record understates it eightfold.

What to record, load by load

If you have a measured figure, record it as it stands, with no marker. If all you have is a limit, record the limit with "above" or "below", so the sofa load goes in as "> 500mg/kg". Either way, keep the evidence you were given, such as the lab report or the producer's note, with your own records.

If you have neither a figure nor a limit, GOV.UK's guidance still applies. Name the chemical, leave the concentration out, and state why, for example that no breakdown came with the waste.

CarrierNote records POPs and hazardous waste on the same receipt as the rest of the load. For each chemical you give its concentration, or choose "Above" (or, for POPs, "Below") and give the limit, and the note prints "> 500 mg/kg". The receipt CarrierNote sends to DEFRA carries the same limit. See how hazardous and POPs loads work at carriernote.co.uk/product.

Sources

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