What is Chromium-6 (Cr VI, Cr-6)?

Chromium-6 in coatings, a problem?

Chromium is a metal that occurs in various forms, including chromium III and chromium VI. Naturally, chromium is almost exclusively found as chromium III. Chromium VI is a deliberately produced form with desirable properties such as good adhesion, rust resistance, and color fastness. While chromium III is an essential nutrient, chromium VI can be harmful to health.

During blasting, spraying, sanding, grinding, sawing, or heating paint containing chromium VI, dust can be released into the air containing chromium VI. Especially during blasting and spraying activities or paint removal, high concentrations of chromium VI can be released into the air. If no or insufficient protective measures are taken, chromium VI can enter the body through:

Inhalation

Eye contact

Skin contact

Ingestion (swallowing)

Hazard and legal regulations

The Health Council in the Netherlands concluded in its report of September 30, 2016, that all chromium (VI) compounds should be considered carcinogenic and that no distinction should be made in health risk calculations between soluble and insoluble compounds. It advises a target value of 0.01 microgram/m³ and a prohibition value of 1 microgram/m³. The legal limit values of 10 and 50 microgram/m³ for respectively soluble and poorly soluble compounds are above the prohibition value.

The Minister of Social Affairs and Employment considers this a socially undesirable situation. Pending a SER advisory, the Minister of Social Affairs and Employment decided to introduce a limit value for all chromium (VI) compounds at the level of the prohibition value, namely 1 microgram/m³ or 0.001 milligram/m³ (as TWA-8 hours). This abolishes the separate rules for specific chromium (VI) compounds, as well as the TWA-15min for some of those compounds.

The legal limit values in Germany are the same as in the Netherlands. In the United Kingdom and Belgium, these values are 0.05 milligram/m³.

Source

Bjond Approach

Because the legal exposure limits are so extremely low, the chance of exceeding them with any traditional form of coating repair is also extremely high. Therefore, there is an urgent need for more knowledge and innovative approaches.

As an independent and expert party, Bjond supports market parties when it comes to chromium-6 in a coating on steel or concrete. Our role is to work with our clients to find solutions for addressing chromium-6 issues in the coating/conservation world. Solutions that are effective and efficient, taking into account the strict legal framework. Together with market parties, we look for alternative removal methods and test them for feasibility.

We offer our knowledge on how the presence of chromium-6 in paint (coating) can be reliably determined. This knowledge is essential because the permitted exposure requirement is very quickly exceeded. With our knowledge of the pros and cons of alternative removal techniques, combined with an innovative perspective, looking beyond existing "walls," and a large network, we are a solid partner for you.

Experiences

We have already initiated interesting solutions together with various parties (Rijkswaterstaat), studied and tested them, and are convinced that more will follow.

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