Substances of Very High Concern - Zinc Borates

Statement on Substances of Very High Concern - Zinc Borates

This statement concerns the following U.S. Borax products:

  • Firebrake® 500: CAS #12767-90-7
  • Firebrake ZB: CAS #138265-88-0

Based on current and available information, the Substances of Very High Concern (SVHC) with the exception of boric acid, as identified on the candidate list as published on the ECHA website are not used in the production process to produce Firebrake ZB and Firebrake 500. Whilst we do not specifically test for their presence it is reasonable to assume they are absent from these products.

Since boric acid is used as an intermediate in the production of Firebrake ZB and Firebrake 500, we have evaluated our products and can confirm the absence of boric acid at a detection limit of 0.1% using X-Ray Diffraction (XRD).

Industry convention means that U.S. Borax’s products are often described in terms of the B2O3 content, but this should not be misinterpreted that the substance boric oxide, exists in the zinc borate products. It is important to distinguish between the convention of expressing the boron (B) content as a percentage B2O3 used to describe a composition and the substance boric oxide itself. Within the context of REACH, it is the substance boric oxide which has been identified as an SVHC and not the boron content (B) expressed as percentage B2O3. Our zinc borate products do not contain the substance boric oxide.


May 2020

U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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