What landfill waste types mean (inert vs special)

Every historic landfill record carries up to six waste-type flags, and they do more work than any other field: the difference between "inert" and "special" is the difference between buried builder's rubble and buried asbestos. These are the licensing-era legal categories, so the words don't always mean what modern usage suggests. Here's each one in plain English, with how often it appears across the 19,851 sites in the Environment Agency's dataset.

The six categories, from lowest to highest concern

Inert — 56% of recorded sites

Builder's rubble, subsoil, concrete, brick, glass. Chemically inactive: it doesn't decompose, produce gas, or leach anything meaningful. The most common category by far (11,118 sites) — a large share of England's historic "landfills" are filled pits and levelled ground rather than anything resembling a rubbish tip. If the only flag on a nearby site is inert, that is close to a non-event.

Commercial — 28%

Waste from shops, offices and trade premises: paper, packaging, food waste. Similar character to household waste, typically smaller volumes.

Household — 27%

Domestic refuse. The organic fraction decomposes and generates landfill gas (methane and CO2) for roughly 20–40 years after tipping stops — the practical questions are covered in our landfill gas guide. Most recorded household sites closed decades ago and are past their gassing peak.

Industrial — 33%

Factory and process waste — the widest category. A furniture maker's offcuts and a plating works' residues both counted as industrial. The operator name and era on the site record are the best free clues to which kind you're looking at; a formal environmental search is the paid answer.

Liquid / sludge — 9%

Liquids and sludges: sewage sludge, industrial effluent, drilling muds. Less common (1,693 sites), and mainly relevant where groundwater matters — private water supplies, or a site immediately upslope.

Special — 5%

The licensing-era term for what we now call hazardous waste: asbestos, chemicals, oils, solvents, clinical waste. Recorded at 980sites — about 1 in 20. A special flag near a property isn't a determination of harm (deposits were often small, contained, and are now capped), but it is the category where paying for a professional assessment is rational rather than anxious.

And the seventh state: not recorded

4,832 sites (24%) have no waste types recorded at all. That's a statement about 1970s paperwork, not about contents. Treat an unrecorded site like a household one unless the name, operator or local history suggests industry — and remember the dataset's bigger gap: tips that closed before 1974 may not be recorded anywhere.

Quick reference

Special:

the licensing-era term for hazardous waste — asbestos, chemicals, oils. The category that most warrants a closer look.

Liquid / sludge:

liquid wastes and sludges, such as sewage sludge or industrial effluent. Can be mobile in groundwater, so worth understanding.

Industrial:

factory and process waste. Contents vary widely — some benign, some not; the site's operator and era are the clues.

Household:

everyday domestic refuse. Decomposes and can generate landfill gas for a few decades after closure.

Commercial:

waste from shops and offices — paper, packaging, food. Similar profile to household waste, usually less of it.

Inert:

builder's rubble, subsoil, concrete, brick. Doesn't decompose or generate gas; the lowest-concern category.

How to use this

1. Search your postcode — every nearby site shows its waste-type chips with these glosses.
2. Rank your attention by the worst flag present, discounted by distance and age — the buying guide walks through exactly that triage.