P233 · Precautionary statementKeep container tightly closed.

Precautionary · PreventionHealthPhysical

P233 is the GHS precautionary statement “Keep container tightly closed”. UN GHS Annex 3 assigns it to 8 hazard classes. The English wording is the same as UN GHS Rev.11 in US OSHA, EU CLP and Canada. Canada’s official French text is “Maintenir le récipient fermé de manière étanche” and Mexico’s Spanish text is “Mantener el recipiente herméticamente cerrado”. In the UN GHS Rev.11 label matrix it is used with 8 hazard statements (UN only).

Maintained by Valenc. Data checked 2026-10-20.

Heading text: UN GHS Rev.11 Annex 3. Wording can differ by jurisdiction; see the table below.

Wording by jurisdiction

UN GHS Rev.11

Same as UN

GHS Rev.11 (2025), Annex 3

Keep container tightly closed.

UN GHS Rev.11, Annex 3, Table A3.2.2, PDF p. 316

US OSHA HCS

Same as UN

HCS 2024 · primarily GHS Rev.7, some Rev.8

Keep container tightly closed.

29 CFR 1910.1200 App. C, matched by wording

EU CLP

Same as UN

EU_CLP_2025 · consolidated 1 Jul 2026

Keep container tightly closed.

EU CLP, Annex IV, Part 2

Canada (EN)

Same as UN

WHMIS_2022 · GHS Rev.7 (Rev.8 for chemicals under pressure)

Keep container tightly closed.

GHS Rev.7 Annex 3 Table A3.2

Canada (FR)

Adopted

WHMIS_2022 · SGH Rév.7, texte officiel

Maintenir le récipient fermé de manière étanche.

GHS Rev.7 Annex 3 Table A3.2

Mexico (ES)

Adopted

NOM-018-STPS-2015 · GHS 5th revised edition

Mantener el recipiente herméticamente cerrado

NOM-018-STPS-2015, DOF 9 October 2015, Apéndice D, Tabla D.1, PDF p. 35

Hazard classes and categories

Flammable liquids (chapter 2.6) · Category 1, 2, 3
Pyrophoric liquids (chapter 2.9) · Category 1
Pyrophoric solids (chapter 2.10) · Category 1
Desensitized explosives (chapter 2.17) · Category 1, 2, 3, 4
Acute toxicity, inhalation (chapter 3.1) · Category 1, 2, 3
Respiratory sensitization (chapter 3.4) · Category 1, 1A, 1B
Specific target organ toxicity, single exposure; respiratory tract irritation (chapter 3.8) · Category 3
Specific target organ toxicity, single exposure; narcotic effects (chapter 3.8) · Category 3

UN GHS Rev.11 Annex 3, sections 1 and 2

H statements it is used with in the UN GHS Rev.11 label matrix only

UN GHS Rev.11 only. EU CLP, US OSHA, Canada (GHS Rev.7) and Mexico assign their own P statements; check the regulation for your market.

H206 H207 H208 H224 H225 H226 H250 H334

UN GHS Rev.11 Annex 3, section 3. Listed for at least one category that uses each H statement.

Conditions for use

if the liquid is volatile and may generate an explosive atmosphere.
if the chemical is volatile and may generate a hazardous atmosphere.
if the chemical is volatile and may generate a hazardous atmosphere.

Quoted as published in UN GHS Rev.11 Annex 3, section 2. List markers are shown as bullets.

Related codes

P403+P233

Change in UN GHS Rev.11

No change to the wording or the hazard classes in Annex 3 compared with Rev.10.

Sources

Each cell in the table names the official table and page for P233. Full citations, links and revision notes for UN GHS Rev.11, US OSHA, EU CLP, Canada and Mexico: Sources and revision notes.

These are regulatory phrases for labels and safety data sheets. Check them against the official source for your jurisdiction before use.