Hexavalent Chromium( Cr 6, Cr VI) compounds

Just as trivalent chromium compounds (3+, III) are non-toxic at appropriate doses and constitute an essential nutritional trace element, hexavalent chromium salts (6+, VI: see list of synonyms) have industrial uses (chrome plating, stainless steel), are oxidising, corrosive, irritating, and are classified as carcinogens 1A and mutagens 1B ^{(Wise 2025, Jiang 2025, Guo 2013, Panreac 2011, WHO-OMS 2012, ATSDR 2012, INSHT 2012, 2010 & 2004, Patlolla 2009, IARC 1990)}, can cause contact dermatitis and severe chronic and acute toxicity ^{(Hald 2009, Lin 2009, André 1998)}. Chromium 6+ is also found in tobacco smoke ^{(ATSDR 2012)}, cosmetics (Hepp 2014) and some osteoarticular prostheses. ^{(Oppermann 2015, Nelis 2013)}

Due to their hazardous nature, hexavalent chromium compounds currently have no medical uses.

 In terms of occupational risk for breastfeeding mothers ^{(INSHT 2024, EC Regulation 2008)}, there are only two risk phrases (formerly R phrases, now H phrases for Hazard) or precautionary phrases (P phrases) in a product's safety data sheet that are relevant to breastfeeding:

• H362 (formerly R64): ‘May cause harm to breastfed children’
• P263: ‘Avoid contact during pregnancy and breastfeeding’

Six other phrases that should be considered during breastfeeding are related to the carcinogenic, mutagenic or cumulative power of a product:

• H350 (formerly R45 and R49): ‘May cause cancer.’
• H351 (formerly R40): ‘Possible carcinogenic effects.’
• H370 (formerly R39): ‘Causes damage to organs.’
• H371 (formerly R68): ‘May cause damage to organs.’
• H372 (formerly R48): ‘Causes damage to organs through prolonged or repeated exposure.’
• • H373 (formerly R33): ‘May cause damage to organs through prolonged or repeated exposure.’

The Cr(VI) data sheet includes phrases H350 (R45) and H372 (R48) ^{(INSHT 2012, 2010 & 2004, Panreac 2011)}, which, based on current European regulations ^{(EC Regulation 2008)}, which states that when a product is carcinogenic and mutagenic, working breastfeeding mothers should not be exposed to mixtures, whether solid, liquid or gaseous, with concentration limits above 0.3%, we consider that breastfeeding mothers should not be exposed to hexavalent chromium compounds in the workplace.

There is no increase in chromium concentrations in milk or problems in infants breastfed by mothers with hip prostheses containing chromium in their composition. ^{(Oppermann 2015, Nelis 2013)}

See below the information of this related product:

• Trivalent Chromium (Cr 3, Cr III) compounds (Safe product and/or breastfeeding is the best option.)