The system of symbols and codes on chemical labels is not arbitrary. The Globally Harmonized System aims to express the same hazard with the same symbol and the same code in every country. In this way, the marking on a container remains readable even when it is sent to a country whose language is unknown.
The system uses three elements together: a pictogram showing the hazard, a signal word indicating its severity and standard statements describing the type of hazard. All three are derived automatically from the classification; they are not left to the free interpretation of the person preparing the label.
What does GHS06 mark?
GHS06 shows a skull and crossbones inside a red-bordered diamond. This pictogram indicates that the substance's acute toxicity has been assessed in the high categories: it means that a single short-term exposure can have severe consequences. The exclamation-mark pictogram, with which it is sometimes confused, marks less severe effects, that is, hazards of the irritant type; the difference from the skull is one of degree, and the two are not expected to be used side by side for the same product.
A signal word appears next to the pictogram. In the high categories this word is Danger, and in lower categories Warning. In the safety data sheet published for our facility's product, the pictogram is given as GHS06 and the signal word as Danger.
The design of the pictogram is also standard: a black symbol on a white background with a red border. The colour and border thickness are specified so that the label can be noticed even on small packages. Changing the symbol freely, or replacing it with a company-designed mark, is not an option.
How are H codes read?
The letter H is short for hazard statement. The first digit of the three-digit number shows the group to which the hazard belongs: those starting with 2 mark physical hazards, those starting with 3 health hazards and those starting with 4 environmental hazards. Acute toxicity statements therefore start with 3.
| Code | Meaning | Route of exposure |
|---|---|---|
| H300 | Fatal if swallowed | Oral |
| H310 | Fatal in contact with skin | Dermal |
| H330 | Fatal if inhaled | Inhalation |
The presence of all three statements together shows that each of the three exposure routes has been assessed separately. Our product's classification carries all three codes: Acute Tox. 2 (H300), Acute Tox. 2 (H310) and Acute Tox. 1 (H330).
The codes are also accompanied by a classification abbreviation. Acute Tox. stands for acute toxicity and the number next to it indicates the category; the H code in brackets repeats the same information as a sentence. This double notation lets the reader of the document see both the class and the statement at a glance.
The information on the label may be shortened according to the size of the package; reduced label layouts are defined for cases where not all statements fit on small containers. Even then, the pictogram, signal word and product identifier are retained.
What does the category number tell you?
The category number in the classification indicates the severity level of the hazard and is read in reverse: the smaller the number, the greater the hazard. Four categories are defined for acute toxicity; 1 is the most severe level and 4 the least. Category 1 for the inhalation route therefore means that this route is assessed as the product's most sensitive route of exposure. This is why particular attention is paid to preventing airborne particles when working with the powder form.
Categories are assigned according to accepted criteria and are reflected on the label by the statement derived from those criteria. When an institution enters the product into its own inventory, looking at the category sets the boundaries of the risk assessment to be carried out from the outset.
The classification decision is not a matter of the supplier's free choice. The available data on the substance are compared against accepted criteria, and the result falls into a category. The competence of the person carrying out this assessment is also required; the classification for our facility's product was prepared by a chemical assessment specialist certified under TÜRKAK accreditation.
P statements and the label as a whole
H statements define the hazard, while P statements describe the precautions to be taken. Precautionary statements are divided into four groups: prevention, response, storage and disposal. The label carries not all of them but a selected set suited to the product; the full list is found in section two of the safety data sheet. The section layout of the sheet is described in the article on the SDS.
A complete label carries the following together: product identifier, supplier details, pictogram, signal word, H and P statements, quantity and, where necessary, additional information. When a shipment is involved, transport marking is added to this label; classification on the transport side is covered in the article on UN 3462. The two marking systems cannot replace each other; one describes the material itself, the other the conditions of its transport.
The physical durability of the label should not be overlooked either. The marking is applied so that it remains legible under transport and storage conditions; a label that is rubbed off or torn away leaves the contents of the container uncertain. Where the official language of the destination country is concerned, the label and documents are also prepared in that language.
Another point is that the label and the document must match. The pictogram and statements on the container should be the same as the classification in the accompanying safety data sheet. If a discrepancy is noticed, the supplier is consulted before the material is put into use; the cause is often an outdated version of the sheet.
What difference does reading the label make?
In a laboratory working with a substance in a high category, the label is not a decorative element but an input to the workflow. Which protective equipment is needed, whether the work should be done in a fume hood and where the sample should be stored all follow from this information. The selection of equipment is described in the article on PPE.
Label information does not replace training; it is expected to be read during preparation and turned into a written working instruction. If exposure is suspected, there is only one step to take: call 112 without delay. Classification and document details are published on the documents page.
