Chromium (VI) has been included in the list of substances subject to authorisation by the European Union through the REACH Regulation (Registration, Evaluation and Authorisation of Chemicals) since 2013. It is suspected of causing serious health problems such as respiratory illnesses and skin irritation and is classified as carcinogenic. Chromium (VI) is formed by oxidation, in particular at high temperatures. The REACH Regulation prohibits and restricts substances, which means that it does not cover processes in which chromium (VI) is produced. However, this is precisely where considerable health risks arise in practice.

For example, millions of stainless-steel screws are used in combination with screw and assembly pastes for bolted connections that are exposed to high temperatures in order to reduce friction between the parts and to ensure that they can be loosened again later. The problem is that at temperatures above 350 degrees Celsius, chromium oxidises from the steel and, promoted by the assembly pastes currently available on the market, compounds such as chromium (VI) are formed.

This process can be recognised by the yellowish discolouration of the screw or assembly paste. Dust containing chromium (VI) may be released – at the latest when the bolted connections are dismantled – which may then be inhaled by fitters or come into contact with their skin or mucous membranes. Currently, the only way to avoid health risks is to carry out such assembly or maintenance work with full respiratory and personal protective equipment. However, this is not always the case in practice; ignorance means that many people are at risk of being exposed to chromium (VI) every day at work.

"This enormous hazard potential and the widespread use of assembly pastes in practically every industrial sector has prompted us to focus our technological expertise in sustainable lubricants on the development of an assembly paste that minimises the formation of chromium (VI). To achieve this, we had to develop new processes and test all the ingredients used so far in order to identify which ones are responsible for these chemical processes. The challenge was then to replace the critical ingredients with non-critical ones without changing the tribological properties," explains OKS Technical Director Joscha Klusmeier, describing the challenges that his research and development team had to solve.

With the new OKS 210 high-temperature paste, users can now benefit from a product that is specially designed to reduce the formation of chromium (VI) when used as an assembly paste. Another advantage is that the paste is NSF-certified and is thus suitable for use in food processing technology.

With this new development, OKS highlights its expertise in the field of user-safe and sustainable lubricants and continues to expand the number of products with enhanced application safety.