20 December 2021
Hexavalent chromium, also known as chromium (VI), chromium 6, or Cr(VI), is chromium in any chemical compound where it is found in its +6 oxidation state.
Hexavalent chromium is used or generated in:
Hexavalent chromium is included in the REACH directive as it is a known human carcinogen. It is a SVHC (Substance of Very High Concern), and the waste produced from industrial processes involving it poses a serious threat to human health. For example, the waste from hexavalent chromium electroplating baths is hazardous. (HSE)
In UK REACH (as in EU REACH) the authorisation process aims to ensure that substances of very high concern (SVHCs) are progressively replaced by less dangerous substances or technologies where feasible alternatives exist. (HSE) Currently a number of industries using substances containing hexavalent chromium, including chromium trioxide, have been granted authorisations for continued use until 2024.
The Authorisation Decision REACH made on the 18th December 2020 now provides the legal boundaries for continued use after the sunset date until the 21st September 2024, for people who purchase the chemical from the EU to use in their own industrial activities. However, the user has to demonstrate the following in order to have the Authorisation Decision apply to them:
Hexavalent chromium forms many different compounds which are largely very unstable. The effects of chromium compounds on human health vary according to water solubility and other factors but it is hexavalent chromium compounds that are the most toxic. All chromates, di-chromates and polychromates fall into this category.
Some of the adverse short-term effects from hexavalent chromium exposures include nasal and sinus cancers, allergic reactions, inflammation of the lungs, kidney and liver damage, nasal and skin irritation, and ulceration. Even single exposures can cause eye irritation and damage and skin irritation upon contact (HSE.org.uk)
To assess the human health impact in the workplace the following can be conducted:
Under the COSHH Regulations exposures should be controlled to levels as low as reasonably practicable (ALARP) by means that are proportionate to the health risk.
Hexavalent chromium has toxic effects on not only humans but also animals, plants, and microorganisms. It can be harmful to the health and reproductive success of any wildlife that ingests it. It can be physically removed from the environment by excavating soil or pumping and treating groundwater to the less toxic form.
Whilst it can get into the environment naturally through processes such as soil erosion, industrial processes also can release Hexavalent Chromium into the environment. Even railway friction and wear can result in hexavalent chromium pollution.
Do you need support with monitoring hexavalent chromium emissions, or help complying with operations conditions like taking annual measurements?