What Hazard Pictograms Leave Off a Chemical Label

A pictogram tells you a class of hazard is present. It stops there.

The Health and Safety Executive (HSE) sets out what each pictogram covers, and the health hazard silhouette appears for carcinogenicity, for germ cell mutagenicity, for reproductive toxicity, for respiratory sensitisation and for specific target organ toxicity. Five very different problems, one symbol, and the control decisions those problems demand have almost nothing in common.

That much is a compression the system openly admits to. What gets less attention is the second layer of compression sitting underneath it, where the rules actively remove pictograms that would otherwise appear. Reading a label carefully still leaves you working from an edited list.

Great Britain runs its own version of the classification system. HSE confirms that the EU CLP Regulation as amended is assimilated into GB law, so Great Britain continues to adopt the United Nations system independently. The pictogram rules described here come from that assimilated text, and how the hazard classes behind them are assigned is a separate question from what reaches the label.

Why a label rarely shows every hazard

Article 26 of the assimilated CLP Regulation sets out rules of precedence. Where a classification would produce more than one pictogram, those rules cut the number that has to be displayed.

The purpose is legibility. A container carrying six diamonds communicates less than one carrying two, because nothing stands out. The consequence is that the label shows a selection, chosen for what communicates fastest.

When the more severe symbol absorbs the milder one

The clearest case is the skull and crossbones. Where acute toxicity triggers GHS06, the exclamation mark GHS07 does not appear for the same hazard. A reader looking for the irritant symbol will not find it, and the irritant classification has not gone anywhere.

Corrosion behaves the same way. Where skin corrosion triggers GHS05, the exclamation mark is dropped for skin irritation, because the more serious classification already covers the ground.

When one physical hazard makes another optional

The exploding bomb carries a broader suppression. Where GHS01 applies, the flame GHS02 and the flame-over-circle GHS03 become optional.

Optional matters here. Two suppliers with identical classifications can produce labels that look different, both of them correct. A comparison between two products based on counting diamonds will mislead you.

The hazards that carry no diamond at all

Suppression is one thing. The other is that certain classified hazards never generate a pictogram in the first place.

Aquatic chronic category 3 is the cleanest example. A substance classified in that category carries the hazard statement and nothing else. No pictogram. No signal word. The classification exists, it appears in section 2 of the Safety Data Sheet, and the container gives no visual sign of it.

HSE makes the wider point plainly, noting that pictograms are only one aspect of a hazard label and that the hazard statements carry information the symbols do not.

For anyone building an inventory from what is visible on the shelf, that is the gap. A container with a single flame diamond can be classified for three or four separate hazards, two of which produce no symbol and one of which has been suppressed by precedence. The Safety Data Sheet holds the full picture. The label holds the summary.

Section 2 of the sheet carries the classification in full, including whatever precedence has removed from the label. Where the copy on file is out of date, current sheets are searchable by substance.

From pictogram to duty

The nine pictograms divide across the same three families the classification system uses, and the families route to different parts of UK law.

The physical hazard symbols cover explosivity, flammability, oxidising properties and gases under pressure. They route to DSEAR and its own assessment duty, which the COSHH file does not reach.

The health hazard symbols cover acute toxicity, corrosion, irritation and the serious long-term effects grouped under GHS08. They engage COSHH, where the hazard statement sets the control standard.

The environment symbol routes away from worker protection law entirely, into permitting and waste duties.

Knowing which family a symbol belongs to answers a more useful question than knowing what the symbol depicts.

The orange squares still in circulation

The red diamonds replaced an earlier set of orange square symbols used under the CHIP regulations. HSE records that CLP replaced CHIP on 1 June 2015, with substances having moved across earlier and older stock lingering on shelves through a sell-through period after that.

The symbols themselves are long gone from new labels. What persists is everything built around them. Laminated wall charts, induction packs, older COSHH Assessments quoting the previous symbol set, and workers who learned the orange squares and were never formally retrained on the diamonds.

That is a training record problem. A worker who confidently identifies an orange square and hesitates over the equivalent diamond has been taught a system that no longer exists on any container arriving on site.

Keeping the reading consistent across a site

One person reads a label and files an assessment. Another reads the same label two years later after a supplier revision and reaches a different conclusion, because the diamonds moved and nobody recorded why.

The pictogram is the shortest summary of a classification. The classification sits in the Safety Data Sheet. The duties sit in the assessment built on both. Three layers, and the risk is that each gets read independently.

Sevron built Safety365 around holding those layers together. COSHH Assessments built against each substance record stay tied to the Safety Data Sheets behind them, so a change in classification surfaces against the assessments it affects without depending on somebody spotting a different symbol on a drum. The Accelerated Compliance framework wraps that in training, which is where the orange square problem gets solved.

The diamonds are a summary written for a glance. The assessment has to be written from the whole thing.

Frequently Asked Questions

How many hazard pictograms are there?

Nine, coded GHS01 to GHS09. They cover physical, health and environmental hazards, and most products carry between one and four.

Do the GHS codes appear on the label?

No. The codes identify the pictograms in classification documents and Safety Data Sheets. The label carries the symbol itself.

Why do two similar products show different pictograms?

Precedence rules under Article 26 can make some pictograms optional where a more severe one already applies. Two suppliers with the same classification can produce labels that look different and are both correct.

Can a substance be classified as hazardous with no pictogram?

Yes. Aquatic chronic category 3 generates a hazard statement with no pictogram and no signal word, and other low-severity categories behave similarly.

What replaced the old orange hazard symbols?

The red diamond pictograms under the CLP Regulation. The orange squares came from the earlier CHIP regime and no longer appear on new labels.

Does a pictogram tell me which regulations apply?

It tells you the family. Physical hazard symbols point to fire and explosion duties, health hazard symbols to COSHH, and the environment symbol to permitting and waste duties.