Hexavalent chromium
Hexavalent chromium also called chromium VI or 6, is one form of chromium. the metallic, naturally occurring element found in rocks, animals, plants, soil, and volcanic dust and gases. It comes in different forms including trivalent chromium chromium (III), and Hexavalent chromium named as such because it is in the +6 oxidation state, which is is industrially produced.
Hexavalent chromium is listed as a known human carcinogen, causing nasal and sinus cancers, kidney and liver damage, nasal and skin irritation and ulceration, and eye irritation and damage. Exposure can occur through breathing it in, ingesting it in food or water, or direct contact with the skin. Industrial workers who use pigments, spray paints, coatings, plating baths; or weld and cut stainless steel can have higher exposure risks.
Hexavalent chromium, is widely used in electroplating or added to anti corrosion agents in coatings, paints and so on, it is used in the production of stainless steel, in leather tanning, in dyes for textile manufacture and some wood preservatives. It is also used in refrigerant solutions and steel parts that might be found in heat pumps.
Hexavalent chromium is covered by the EU and UK Restriction of Hazardous Substances in Electrical and Electronic Equipment (RoHS) directive and regulations, meaning its use is restricted to 0.1% in products through application and monitored, along with other substances that include lead, cadmium, mercury, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE), bis(2-ethylhexyl) phthalate (DEHP), butyl benzyl phthalate (BBP), dibutyl phthalate (DBP) and diisobutyl phthalate (DIBP).
In 2023 the EU however revised hexavalent chromium restrictions and published a new RoHS exemption (entry 9(a)-III in Annex III) for hexavalent chromium as an anticorrosion agent in gas absorption heat pumps. It concluded that it is currently scientifically and technically impracticable to replace its usage in these devices. A maximum concentration of 0.7 % hexavalent chromium by weight in the refrigerant solution is considered sufficient which is only valid for gas absorption heat pumps for space and water heating.
[edit] Related articles on Designing Buildings
- Electrical and electronic equipment
- End of life potential.
- Environmental impact assessment EIA.
- Environmental plan for building design and construction.
- Glossary of electrical terms.
- Hire, reclaim and reuse scheme combats construction waste.
- How to conduct a pre-demolition audit.
- Plastic and recycling.
- Primary non-rechargeable batteries.
- Rare earth metals.
- Restriction of Hazardous Substances in Electrical and Electronic Equipment RoHS
- Recycling explained.
- Secondary rechargeable batteries.
- Types of plastic in construction.
- Waste and Resources Action Programme WRAP.
- Waste hierarchy.
- Waste management plan for England.
Featured articles and news
Biodiversity net gain, tips and tools for small sites
How to deal with BNG when options become limited.
Registered building inspectors
Building types and conflicts of interest updates explained.
A brief run-down reminder of key points to note.
BSRIA's commitment to sustainability and net zero
Key documents that represent an early shift in thinking.
A resource for Cleaner Air, Better Tomorrow.
Awe-inspiring medieval great barns.
A history of timber construction in the UK
From a timber Stonehenge to half timber houses.
Engineering services still struggle with labour shortages
According to latest quarterly services survey of the sector.
Infrastructure that connect the physical and digital domains.
Harnessing robotics and AI in challenging environments
The key to nuclear decommissioning and fusion engineering.
BSRIA announces Lisa Ashworth as new CEO
Tasked with furthering BSRIA’s impressive growth ambitions.
Public buildings get half a million energy efficiency boost
£557 million to switch to cleaner heating and save on energy.
CIOB launches pre-election manifesto
Outlining potential future policies for the next government.
Grenfell Tower Inquiry announcement
Phase 2 hearings come to a close and the final report due in September.
Progress from Parts L, F and O: A whitepaper, one year on.
A replicated study to understand the opinion of practitioners.