What does P420 mean?

What kind of precautionary statement is P420?

Storage statements (P4xx) set the conditions for keeping the product safely: locked up, in a cool, well-ventilated place or in the original container, protected from sunlight. Warehouse layout and container choice follow from these statements.

Which hazards is it used for?

In the CLP Annex IV assignment table, P420 is assigned to the classes of these hazard statements:

• H240Heating may cause an explosion.
• H241Heating may cause a fire or explosion.
• H242Heating may cause a fire.
• H251Self-heating: may catch fire.
• H252Self-heating in large quantities; may catch fire.

How many hazard statements is P420 assigned to?

In the CLP Annex IV assignment table, P420 is provided for the classes of 5 H statements in total: 5 physical hazard statements. The lowest-numbered example is H240 and the highest-numbered is H252. Whether a mixture label carries this statement depends on those classes really applying to the mixture.

Neighbouring statements of the same kind

The statements closest in number to P420 in the storage group:

• P411Store at temperatures not exceeding … o C/… o F.
• P412Do not expose to temperatures exceeding 50 o C/122 o F.
• P413Store bulk masses greater than … kg/… lbs at temperatures not exceeding … o C/… o F.
• P422Store contents under …

How is P420 read?

The length of P420 is 2 words. The text is a single instruction without options and is written as it appears in Annex IV.

Where is P420 written in the SDS?

When you prepare an SDS, P420 goes into Section 2.2; options in the text (slashes or square brackets) are narrowed down to the product before it is written. The statement should also agree with the safe storage conditions in Section 7.2.

How does P420 appear on the label?

The classes and the use of the product decide whether it reaches the label; not all candidates are written, at most 6 statements remain. In the Chemoris selection method, storage statements are considered in position 3. If the core statements exceed 6, Article 28(3) allows up to 8; when a combined statement is chosen, its individual parts are not repeated on the label. As P420 is on the list of precautionary statements of Annex IV, it can be used in current labels and SDSs; Chemoris writes it into the document only when the relevant storage candidate is selected.

Which classes and which priority is P420 assigned to?

In the CLP Annex IV assignment table, P420 appears in 3 class/category entries (1 different H statements). Priority split: secondary (priority 2) in 3 entries. Of these entries, 0 carry the signal word “Danger”, 0 carry “Warning” and 3 need no signal word.

The class families it appears in most often: Self-react. * (1), Org. Perox. * (1) and Self-heat. * (1).

Classes that P420 is assigned to

The first 3 rows of 3 entries in the CLP Annex IV assignment table (by priority and hazard order):

Statements assigned together with P420

The precautionary statements that most often appear with P420 in the same class entries (with entry count):

• P280Wear protective gloves/protective clothing/eye protection/face protection. (3)
• P370+P378In case of fire: Use… to extinguish. (2)
• P370+P380+P375In case of fire: Evacuate area. Fight fire remotely due to the risk of explosion. (2)
• P210Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking. (2)
• P220Keep away from clothing and other combustible materials. (2)

Where does P420 stand in the storage group?

P420 is number 12 of the 19 statements in the P4xx group. The group holds 6 combined and 2 withdrawn statements and 12 single valid statements. Combined statements merge several situations on one line; withdrawn statements are replaced by their current equivalents.

Which SDS section does P420 feed?

Because of its number and its storage kind, P420 relates to Section 7 Handling and storage of the SDS; in Section 2.2 it is written with its code and text. Statements in the same number range feed the same section.

Checklist when writing P420

• P420 should agree with Section 7; in Section 2.2 it is written with its code and text.
• The text is 2 words long; if the label space is narrow, choosing a combined statement can save room.

Official EU wording of P420 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 P420 from the CLP Annex III/IV language versions published in the Official Journal of the European Union. Source: EUR-Lex CELEX 02008R1272-20260701.

Next steps

To read a statement like P420 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.

Where does it appear in the safety data sheet?

Precautionary statements are given with their code and full text in Section 2.2 (label elements) of the safety data sheet. Alternatives separated by a slash or in square brackets (e.g. gloves/protective clothing) are narrowed down to suit the product.

Frequently asked questions