What does H221 mean?

Categories and label elements

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 H221 written in the SDS?

In the prepared SDS the class "Flam. Gas 2" is matched with the code in Section 2.1, the text of H221 is written in Section 2.2 next to the pictogram and signal word, and the class of the component shows up in Section 3. Section 16 collects the full text of the H statements cited by code. For H221, 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 H221 appear on the label?

When you see H221 on a label it is accompanied by no pictogram, and it is written with the signal word "Warning". 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, 4 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 H221 are given together.
• Section 2.2: label elements; H221 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 H221

The values below come from the Chemoris rule file (CLP Annex I). They show the condition under which H221 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 H221 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)).

H221 compared with H220 and H222

The table below puts H221 next to its closest neighbouring statements; the values are read from the rule data.

The signal word differs: Warning for H221, Danger for H220. The pictogram differs: none for H221, GHS02 for H220. The signal word differs: Warning for H221, Danger for H222. The pictogram differs: none for H221, GHS02 for H222.

H220 H222

In which SDS sections does H221 appear?

H221 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 H221

H221 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 4 candidates for this class:

The none pictogram and “Warning” 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 H221 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 H221 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 H221

• Deriving the class from percentages: H221 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)).
• Mixing up signal words: if any class requires “Danger”, only “Danger” is printed and “Warning” drops out (CLP Article 20(3)).
• 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 H221 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 H221 (Flam. Gas). The difference between categories mostly comes from the degree of severity.

• H220Extremely flammable gas.

Frequently asked questions