Iron Oxides



Synthetic Iron Oxide
Iron Oxides and Hydroxides

Iron Oxide Black
INS No. 172(i)
CAS No. 1317-61-9
CI No. 77499
CI Pigment Black 11

Iron Oxide Red
INS No. 172(ii)
CAS No. 1309-37-1
CI No. 77491
CI Pigment Red 101 and 102

Iron Oxide Yellow
INS No. 172(iii)
CAS No. 51274-00-1
CI No. 77492
CI Pigment Yellow 42 and 43

Physical Description

Iron Oxides are naturally occurring pigments, ranging from black, yellow, red and brown in color. However, commercial forms are produced by synthesis. They impart pastel shades as opposed to some of the brighter and clean shades imparted by other colors.

Common Uses

Typical applications include pet foods, confectionery, cosmetics, and pharmaceuticals.


EU Commission Regulation (EU) No 231/2012

Codex Provisions

Iron oxides are added to foods and beverages at concentrations up to a maximum permitted level (MPL) as established by the Codex Alimentarius Commission and published in the General Standard of Food Additives (GSFA).The provisions are defined at the additive group level, and thus apply to the total content of the additives participating in this group: Iron oxide, black (172(i)); Iron oxide, red (172(ii)); and Iron oxide, yellow (172 (iii)).

Regulatory Approvals

USA: Synthetic iron oxide is a color additive exempt from certification and permanently listed for food use in sausage casings for humans: ≤ 0.10% by wt. of finished food; Hard and soft candy, mints and chewing gum at GMP; Pb spec. ≤ 5 ppm; cat & dog food: ≤ 0.25% by wt of finished food (21 CFR 73.200), permanently listed for drug use in drugs generally; limit for ingested drugs nte 55% pigment (21 CFR 73.1200) and as iron oxides permanently listed for cosmetic use in in cosmetics generally, including those for eye area at GMP (21 CFR 73.2250).

JECFA: ADI of 0-0.5 mg/kg body weight (1980)

EC: No ADI allocated (EFSA, 2015). Maximum levels of iron oxides and hydroxides have been defined in Annex II to Regulation (EC) No 1333/2008 on food  additives,  as  amended.  Currently, iron oxides and hydroxides are authorized food additives in the EU and permitted to be used in foodstuffs at quantum satis (QS), except in entire fresh fruit and vegetables (at 6 mg/kg).

Safety Assessment

JECFA last evaluated iron oxides at its 23rd meeting, noting that studies on the bioavailability of iron from these compounds suggest that ferric oxide is less available as a source of biologically active iron than are other forms of iron. A few studies on dogs and cats indicate that levels of up to 10 g/kg of iron oxide in the diet do not result in adverse effects. It was also shown that rats consuming more than 50 mg/kg of body weight of iron oxide for 8 generations showed no effects on reproduction. An ADI of 0-0.5 mg/kg of body weight was established.

Safety Reviews

ANS Panel (EFSA Panel on Food Additives and Nutrient Sources added to Food), 2015. Scientific Opinion on the re-evaluation of iron oxides and hydroxides (E 172) as food additives. EFSA Journal 2015;13(12):4317, 57 pp. Available online

JECFA (1980). Toxicological evaluation of certain food additives. 23rd Report of the Joint FAO/WHO Expert Committee on Food Additives. WHO Food Additive Series No. 14. Available online