PBT and vPvB

The combination is what makes them worrying. A persistent chemical stays in the environment, a bioaccumulative one concentrates in organisms, and a toxic one causes harm. Together these properties mean that damage can occur far from the source and long after release, and that cleanup is difficult or impossible once the chemical has spread.

The concept is defined in detail in the EU REACH regulation, which sets criteria for each property and even stricter ones for vPvB. Substances meeting the criteria can be identified as substances of very high concern, which brings extra duties for suppliers and may lead to authorization or restriction.

The assessment is made by the supplier or registrant, and the result appears in the SDS, where it may say the substance is PBT or vPvB, that it does not meet the criteria, or that an assessment was not required. Mixtures may state that they contain a PBT component above a stated threshold.

Handlers should follow release prevention measures strictly for these materials, because normal dilution and wastewater treatment do not protect the environment. They also appear in other chemical programs worldwide, though definitions and numerical criteria differ by jurisdiction.