EWC chapter 06: inorganic chemical processes waste codes explained

Acid plants, alkali manufacturers, fertiliser producers, chlor-alkali facilities and inorganic pigment works all generate waste under EWC chapter 06. Nearly two-thirds of its codes are hazardous — and every named acid and base code carries an asterisk. Here is the complete chapter 06 breakdown, the subcategory structure, and the records each waste type requires.

What is EWC chapter 06?

The chapter applies to any business that manufactures, formulates, supplies or uses inorganic chemicals. That includes acid and alkali producers, fertiliser and nitrogen chemistry plants, chlor-alkali facilities (chlorine and sodium hydroxide production), silicon chemical manufacturers, inorganic pigment works (including titanium dioxide producers), and operations that process asbestos-containing materials in a chemical context.

Chapter 06 covers inorganic chemistry. If your process manufactures or uses organic chemicals instead — plastics, pharmaceuticals, paints — use chapter 07 (organic chemical processes) or chapter 08 (coatings, adhesives and inks). Chapter 11 covers surface treatment and electroplating wastes, which share some chemical inputs but have their own dedicated codes.

How many codes are in EWC chapter 06?

Subcategory 06 01 — waste acids: are they all hazardous?

Subcategory 06 01 covers waste from the manufacture, formulation, supply and use of acids (MFSU of acids). Every named acid is classified as absolute hazardous — meaning the code is always hazardous regardless of concentration, with no paired non-hazardous mirror entry:

All 06 01 codes except 06 01 99 are absolute hazardous. That means sulphuric acid waste, hydrochloric acid waste and hydrofluoric acid waste each require a hazardous waste consignment note and an upper-tier registered carrier, regardless of the concentration at which they are generated.

Subcategory 06 02 — waste bases

Subcategory 06 02 covers the MFSU of bases. Its structure mirrors 06 01: a set of named absolute hazardous entries and one non-hazardous not-otherwise-specified catch-all (06 02 99). Note that there is no code 06 02 02 — the numbering jumps from 06 02 01 to 06 02 03.

Subcategory 06 03 — salts, solutions and metallic oxides: what is the cyanide rule?

The mirror structure in 06 03 means you must assess whether your salt or metallic oxide waste contains cyanides or heavy metals at levels that trigger the hazardous classification. Common salt process wastes that fall under 06 03 14 (non-hazardous) include sodium chloride solutions and calcium chloride by-products from processes that do not introduce cyanides or heavy metals.

Subcategory 06 07 — halogen process wastes: asbestos and activated carbon

The chlor-alkali industry — which produces chlorine and sodium hydroxide by electrolyzing brine — generates all four hazardous waste types. Older mercury-cell and diaphragm-cell plants are the main source of 06 07 01* (asbestos-containing waste from electrolysis) and 06 07 03* (mercury- contaminated barium sulphate sludge). Modern membrane-cell plants avoid these streams but still generate contact acid wastes (06 07 04*) and spent activated carbon (06 07 02*).

Subcategory 06 13 — catch-all: asbestos processing and biocides

Key 06 13 codes to know:

• →06 13 01* — inorganic plant protection products, wood-preserving agents and other biocides. Covers inorganic pesticides (e.g. copper-based fungicides, arsenic compounds historically used as wood preservatives) generated during manufacture or formulation.
• →06 13 02* — spent activated carbon from inorganic processes other than chlorine production. Use this for exhausted carbon from gas purification, water treatment within an inorganic chemical plant, or any non-chlorine inorganic process. Do not use it for spent carbon from chlorine production (that is 06 07 02*) or from organic chemical processes (which fall into chapter 07).
• →06 13 03 — carbon black. Non-hazardous. Covers the fine carbon particulate produced as a by-product in certain inorganic chemical and combustion processes. Note: carbon black used as a reinforcing agent in rubber manufacture generates waste under chapter 07, not 06.
• →06 13 04* — wastes from asbestos processing. The broader asbestos processing code, covering any inorganic chemical operation that handles, shapes or processes asbestos-containing materials, beyond the electrolysis-specific 06 07 01*.
• →06 13 05* — soot. Soot from industrial inorganic chemical processes, where the soot contains polycyclic aromatic hydrocarbons (PAHs) or other dangerous substances at hazardous concentrations.

Chapter 06 vs chapter 07: which applies to chemical manufacturing?

The chapter boundary follows whether the primary chemical being produced or processed is inorganic or organic. A fertiliser plant making ammonium nitrate (inorganic) uses chapter 06 for its process waste. A pesticide formulator making organic active ingredients uses chapter 07. An adhesives manufacturer uses chapter 08. If a process generates both organic and inorganic wastes, classify each stream under the chapter that matches its specific origin.

What records do chapter 06 wastes require?

Because 29 of the 48 chapter 06 codes are hazardous, most inorganic chemical process wastes will need a consignment note. The key compliance steps for hazardous chapter 06 waste are:

• →Confirm the EWC code using the classification order in the List of Wastes — start with the most specific subcategory before defaulting to the 99 catch-all.
• →Check whether the code carries an asterisk. Absolute hazardous codes (with no non-hazardous mirror) are always hazardous. Mirror entries require a classification assessment to determine whether your specific waste exceeds the hazardous thresholds.
• →Complete a pre-notification to the Environment Agency (or SEPA, NIEA, or NRW in Scotland, Northern Ireland and Wales) if the receiving site requires it for that waste type.
• →Use an upper-tier registered carrier. All chapter 06 hazardous wastes require an upper-tier registration; lower-tier registration is not sufficient.
• →Keep the consignment note for at least 3 years (versus 2 years for a non-hazardous WTN).

This guide is general information about EWC codes and waste classification, not legal advice. Classification decisions should be checked against the current UK List of Wastes and, where necessary, confirmed with your environmental regulator or a qualified waste classification specialist.