Chlorine

INS 925CAS 7782-50-5

Listed as a flour treatment agent by Canada and Codex.

Listed as flour treatment agents (CA, Codex) · preservatives (US) · acidity regulators (US) · oxidising and reducing agents (US)
Chemical structure of Chlorine, from PubChem compound 24526
Structure from PubChem CID 24526 (National Library of Medicine, public domain). A depiction of one compound: where a listing covers a family, or a substance has no single structure, this page shows none.

Chlorine is a flour treatment agent. Chlorinating soft flour is what makes American-style high-ratio cake possible: a cake carrying more sugar and liquid than flour, which untreated flour cannot hold.

Where it is and isn’t permitted

Status of Chlorine by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
Australia and New ZealandFood Standards Australia New ZealandNo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
CanadaHealth CanadaPermitted

no numerical limit (good manufacturing practice)

In: White flour; Whole wheat flour. Purpose: Flour treatment agent. Limit: Good Manufacturing Practice.

Health Canada, List of Permitted Flour Treatment Agents (List 2), item C.4retrieved 2026-10-17
European UnionEuropean Commission / EFSANo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
Great BritainFood Standards Agency / Food Standards ScotlandNo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
JapanConsumer Affairs AgencyNo listing matchedThis site imports only Japan’s list of designated additives (Appended Table 1 to the Regulations for Enforcement of the Food Sanitation Act), matched by English name. Existing additives, natural flavouring agents and ordinary foods used as additives are permitted outside that list and are not imported, so an empty row does not show that Japan does not permit the substance.
South KoreaMinistry of Food and Drug SafetyPermitted, with conditions
Designated food additive: Standards and Specifications for Food Additives, Part III, 1. …

Designated food additive: Standards and Specifications for Food Additives, Part III, 1. 일반식품첨가물 (general food additives), 염소 (“Chlorine”, the English the Code prints beside it). Main use (주용도) of 염소: 밀가루개량제. Standard for use (사용기준) of 염소: (1) [may be used only in the foods listed; sets a limit on the amount used] “염소는 아래의 식품에 한하여 사용하여야 한다. 염소의 사용량은 1. 밀가루류 : 2.5g/kg 이하” The Korean is the standard as published. There is no official English translation of the current Code (the English version on MFDS’s website is the 2020 edition and has no legal effect); the English in square brackets is this site’s description of what each sentence does, not a translation of the foods or the levels. Compositional specifications (Part IV) are not imported, nor are the general standards in Part II, which apply to every additive.

Standards and Specifications for Food Additives (식품첨가물의 기준 및 규격), MFDS Notification, Part III (Standards for use, by item)retrieved 2026-10-18
United StatesFood and Drug AdministrationNot listedDoes not appear on this jurisdiction’s permitted list. That is not the same as being prohibited.
Codex AlimentariusCodex Alimentarius Commission / JECFAPermitted, with conditions

1 food category

highest permitted level 2,500 mg/kg

Note 87 On the treatment level basis.

Note 471 In products conforming to the Standard for Wheat Flour (CXS 152-1985), only for use in flours for high ratio cakes.

CXS 192-1995 Table One, INS 925, food category 06.2.1retrieved 2026-09-07

How much is permitted

A listing usually limits the quantity as well as the food. Only one of the forms that takes is a figure: quantum satis and good manufacturing practice permit the amount the technological effect requires and no more, which is a limit rather than the absence of one. Figures below are the range across every food category this page is listed in, and categories differ between regulators — see how much is permitted.

Canada—1 GMP
South Korea—1 no quantity stated
Codex Alimentarius2,500 mg/kg1 numeric limit

What FDA’s inventory records

This page holds no listing for Chlorine in the parts of 21 CFR this site reads. FDA’s Substances Added to Food inventory does carry it, as CHLORINE, pointing at a standard of identity for a particular food: 21 CFR 137.105, 21 CFR 137.200.

Technical effects FDA records: antimicrobial agent, fumigant, oxidizing or reducing agent, ph control agent.

The inventory is an information resource: a row means FDA holds information about the substance’s use in food, not that the substance is listed for that use. It is shown apart from the permissions above and is not counted as a US permission anywhere on this site.

What it is made from

Produced by electrolysing brine. Applied as a gas to flour, where it oxidises the surface of the starch granules and the flour proteins.

  • Vegan
  • Vegetarian

Compare other additives on the dietary indexes.

CAS registry number
7782-50-5
InChIKey
KZBUYRJDOAKODT-UHFFFAOYSA-N
PubChem
CID 24526

How JECFA defines it

The international specification for identity and purity, prepared by the Joint FAO/WHO Expert Committee on Food Additives and published by FAO. It is a different document from any above, written by a different body and revised on its own cycle; it is advisory, and a country adopts it or does not.

INS 925 Chlorine

Synonyms: INS No. 925

Assay, identification and purity criteria

Description and assay

Specification history
Prepared at the 28th JECFA (1984), published in FNP 31/2 (1984) and in FNP 52 (1992) Metals and arsenic specifications revised at the 63rd JECFA (2004). A treatment level of 2.5g Chlorine /kg flour was established at the 29th JECFA (1985)
Chemical names
Chlorine
C.A.S. number
7782-50-5
Chemical formula
Cl 2
Formula weight
70.91
Assay
The content of the vapourized liquid shall be not less than 99.5% of Cl 2 (v/v)
DESCRIPTION
Liquid chlorine is a clear yellow liquid which on vapourizing yields a greenish yellow gas. It is gaseous at atmospheric temperatures and pressures but normally supplied under pressure in containers in which it is present in both liquid and gaseous phases. Such containers should meet appropriate requirements for the transportation and storage of hazardous gases. Caution: Chlorine gas is a respiratory irritant. Large amounts cause coughing, laboured breathing and irritation of the eyes. In extreme cases the difficulty in breathing may cause death due to suffocation. Liquid chlorine causes skin and eye burns on contact. Safety precautions to be observed in handling the material are available, e.g., in the Chlorine Manual obtainable from the Chlorine Institute, 342 Madison Avenue, New York, N.Y. 10017, USA.
FUNCTIONAL USES
Flour treatment agent, bleaching agent
METHOD OF ASSAY
Determine by ASTM Method E 412-70, "Assay of Liquid Chlorine (Zinc Amalgam Method)".

Identification

Solubility (Vol. 4)
Very soluble in water
Test for chlorine
Cautiously pass a few ml of chlorine gas through 10 ml of sodium hydroxide TS that has been previously chilled in an ice bath. The resulting solution gives positive tests for Chloride and it darkens starch iodide paper.

Purity criteria

Moisture
Not more than 150 mg/kg Determine by ASTM method E 410-70 "Moisture and Residue in Liquid Chlorine"
Residue on evaporation
Not more than 150 mg/kg Determine by ASTM method E 410-70 "Moisture and Residue in Liquid Chlorine"
Mercury (Vol. 4)
Not more than 1 mg/kg Dissolve the residue obtained in the Test for Residue on evaporation in 2.5 ml of freshly prepared aqua regia and dilute with water to a volume in ml equivalent to the weight in g of the initial chlorine sample, so that 1 ml of the final dilution is equivalent to 1 g of chlorine. Transfer 2.0 ml of the Sample Solution into a 50 ml beaker, add 10 ml of water, 1 ml of dilute sulfuric acid (1 in 5), and 1 ml of potassium permanganate solution (1 in 25), cover with a watch glass, boil for a few sec, and cool. Use the resulting solution as the Sample Preparation for the Limit Test.
Lead (Vol. 4)
Not more than 2 mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, “Instrumental Methods.”

FAO JECFA Monograph 1 (2006)

Every name it appears under

64 recorded names. A label may use any of them.

INS number

  • 925

CAS registry number

  • 7782-50-5
  • 81859-29-2

Other names

  • Bertholite
  • Bertholite /warfare gas/
  • Caswell No. 179
  • CCRIS 2280
  • Chloor
  • Chlor
  • Chlore
  • chloride content of cement raw meal
  • CHLORINE
  • Chlorine (Cl)
  • Chlorine - Cl @ 1.00 wt% in 75 cSt Mineral Oil
  • Chlorine - Cl @ 10 microg/g in 75 cSt Mineral Oil
  • Chlorine - Cl @ 100 microg/g in 75 cSt Mineral Oil
  • Chlorine - Cl @ 1000 microg/g in 75 cSt Mineral Oil
  • Chlorine - Cl @ 5 microg/g in 75 cSt Mineral Oil
  • Chlorine - Cl @ 5 microg/g in 75 cSt Oil
  • Chlorine - Cl @ 50 microg/g in 75 cSt Mineral Oil
  • Chlorine - Cl @ 5000 microg/g in 75 cSt Oil
  • Chlorine 35
  • Chlorine Blank (0 wt%) in 75 cSt Mineral Oil
  • Chlorine Blank - Cl @ 0 microg/g in 75 cSt Mineral Oil
  • Chlorine gas
  • Chlorine mol.
  • Chlorine Standard: Cl @ 10 microg/g (0.0010 wt%) in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 100 microg/g (0.0100 wt%) in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 1000 microg/g (0.100 wt%) in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 10000 microg/g (1.00 wt%) in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 20 microg/g in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 200 microg/g (0.0200 wt%) in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 2000 microg/g (0.200 wt%) in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 25 microg/g in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 250 microg/g (0.0250 wt%) in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 50 microg/g in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 500 microg/g (0.0500 wt%) in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 50000 microg/g (5.00 wt%) in 75 cSt Mineral Oil
  • Chlorine Standard: Cl @ 75 microg/g in 75 cSt Mineral Oil
  • Chlorine, >=99.5%
  • Chlorine, puriss., >=99.8%
  • Chlorine-35
  • Chlorine-elemental
  • Chlorinum
  • Chloroniumchlorid
  • chorine chloride
  • Cl
  • Cl2 Gas
  • Cloro
  • Coal - Chlorine (NIM-GBW11118)
  • dichlorane
  • dichlorine
  • Dietary Chlorine
  • Disinfectant(NaClO)
  • EPA Pesticide Chemical Code 020501
  • Gas, Chlorine
  • Gas, Cl2
  • HBA Disinfectant
  • HSDB 206
  • INS NO.925
  • INS-925
  • Molecular chlorine
  • Total Chlorine

Systematic names

  • Molecular chlorine

Hazard reference values

Values set by assessing bodies. A body that has not set a value is not listed here.
TypeValuePopulationAssessed byOpinion
TDI0.15 mg/kg bw/dayconsumersEFSA AFC2006

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated rather than machine-read, and none has been written for this substance yet.

Common questions

Assembled from what is above, in the words the questions are usually asked in. Each answer is the same statement the relevant section makes, with the same citations behind it.

What is INS 925?
INS 925 is Chlorine. Chlorine is a flour treatment agent. Chlorinating soft flour is what makes American-style high-ratio cake possible: a cake carrying more sugar and liquid than flour, which untreated flour cannot hold.
What is Chlorine used for in food?
It is listed as a flour treatment agent — the role Canada and Codex assign it. This page shows every function each regulator records, with the citation for each.
Where is Chlorine permitted?
Of the seven regulators this site reads, Canada, South Korea and the Codex standard permit it. Each permission is for named foods at named levels, not a blanket one; the table on this page gives them with citations.
Is Chlorine vegan?
Yes. Chlorine is not derived from animals, and is suitable for vegetarians. This page says what it is made from and how.

Sources for this page

  • ca retrieved 2026-10-17
  • kr retrieved 2026-10-18
  • gsfa retrieved 2026-09-07
  • jecfaspecs retrieved 2026-09-23

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable: a JSON record of this additive is given on request —how to ask for access.

Follow changes to Chlorine:Atom feed — regulatory events, and any change the weekly refresh detects in its provisions.