What does H240 mean?

Categories and label elements

CLP abbreviation	Pictogram	Signal word
Self-react. A	GHS01Exploding bomb	Danger

Related precautionary statements (P codes)

The precautionary statements that CLP Annex IV assigns to this class. Not all of them go on the label: under CLP Article 28(3), no more than six precautionary statements appear on the label unless the nature and severity of the hazard require more; the selection depends on the product and its users.

Where is H240 written in the SDS?

In the SDS, H240 ("Heating may cause an explosion.") first enters Section 2.1 as a classification, written as "Self-react. A" together with the code. Section 2.2 then gives its full text as a label element. Components that have this class are listed row by row in the Section 3 table; in addition, it must agree with the physical and chemical properties in Section 9 and, if the product is subject to transport rules, it is read together with the ADR information in Section 14.

How does H240 appear on the label?

On the label H240 appears with the pictogram GHS01 (exploding bomb), and it is written with the signal word "Danger". In the Chemoris template Section 2.2 carries at most 8 H statements; if the limit is exceeded the least severe ones are dropped and a warning is shown. For the bottom of the label, 10 P statements are candidates for this class in CLP Annex IV; under CLP Article 28 at most 6 of them are selected.

Where does it appear in the safety data sheet?

• Section 2.1: classification; the class abbreviation and H240 are given together.
• Section 2.2: label elements; H240 with its full text, pictogram and signal word.
• Section 3: composition table; in the row of every component that has this class.
• Section 16: the full text of the H statements cited as codes in earlier sections.

Class criteria and thresholds for H240

The values below come from the Chemoris rule file (CLP Annex I). They show the condition under which H240 arises in a mixture. For physical hazards and other classes that depend on test data, the result comes from the mixture's own measurement, not from component percentages.

The class behind H240 depends on the mixture's own test data; the Chemoris rule file does not derive it from component percentages and warns the chemist when a component carries it (≥ 1 %) (CLP Annex I 2.x (for physical hazards 1.1.1.3 / Article 6(5) data requirement); 2.16.3 (metal-corrosive mixture)).

H240 compared with H241 and H242

The table below puts H240 next to its closest neighbouring statements; the values are read from the rule data.

H240 and H241 carry the same signal word (Danger). The pictogram differs: GHS01 for H240, GHS01, GHS02 for H241. H240 and H242 carry the same signal word (Danger). The pictogram differs: GHS01 for H240, GHS02 for H242.

H241 H242

In which SDS sections does H240 appear?

H240 does not stay only in the label section of an SDS; the class itself and the precautionary statements assigned to it shape the content of other sections too. The counts are calculated from the P statements that Annex IV assigns to this class.

Statements that appear on the label together with H240

H240 is never printed alone on a label; it sits next to the pictogram and the signal word. The Chemoris selection method (response, prevention, storage, disposal in that order; core statements first) gives these first 5 candidates for this class:

The GHS01 pictogram and “Danger” are printed together. This ranking applies because a label usually carries at most 6 statements; when a combined statement is selected, its parts are not printed again.

Official EU wording of H240 in other languages

When a product is exported to the EU, the SDS and label are expected in the official language of the Member State where it is placed on the market (REACH Article 31(5)). The table gives the official wording of H240 from the CLP Annex III/IV language versions published in the Official Journal of the European Union. Source: EUR-Lex CELEX 02008R1272-20260701.

Common mistakes with H240

• Deriving the class from percentages: H240 cannot be calculated from component percentages; the mixture's own test data is required (CLP Annex I 2.x (for physical hazards 1.1.1.3 / Article 6(5) data requirement); 2.16.3 (metal-corrosive mixture)).
• Pouring every P candidate onto the label: there are 10 candidates, but CLP Article 28(3) limits a label to 6 precautionary statements (up to 8 when needed).
• Writing unlimited H statements for a multi-class product: in the Chemoris template, Section 2.2 holds at most 8 H statements.

Next steps

To read a statement like H240 correctly on a label and in an SDS, see the guide How to read H and P codes; to pick the class and prepare the label automatically, use the free label tool.

Related hazard statements

Other H statements in the same hazard family as H240 (Self-react.). The difference between categories mostly comes from the degree of severity.

• H241Heating may cause a fire or explosion.
• H242Heating may cause a fire.

Frequently asked questions