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PBT and vPvB substances

What are they?


Toxic, persistent and bioaccumulative substances (TPB or PBT) are substances that simultaneously have three properties:


  1. Persistent (P): they degrade slowly and may remain in the environment for long periods.
  2. Bioaccumulative (B): they can accumulate in living organisms and increase in concentration in certain tissues.
  3. Toxic (T): they have toxic properties which, together with their persistence and bioaccumulation, result in a high level of concern for human health or the environment.


There is also a group of substances that are very persistent and very bioaccumulative (mPmB or vPvB). These substances have particularly high persistence and bioaccumulation potential, although they do not have to meet the toxicity criterion required for PBT substances.


Because of their intrinsic properties, PBT and vPvB substances can remain in the environment for long periods and accumulate in organisms, including human beings. They are therefore a group of substances of particular environmental concern.


The REACH Regulation considers PBT and vPvB substances to be substances of very high concern (SVHC) when they meet the criteria established in Article 57. The criteria for their identification are set out in Annex XIII of REACH.


Official sources:

  1. REACH Regulation (EC) No 1907/2006 – Annex XIII
  2. ECHA – PBT assessment list
  3. ECHA – Candidate List of substances of very high concern


How are they identified?


The REACH Regulation establishes specific criteria for determining whether a substance is PBT or vPvB.


For a substance to be considered PBT, it must meet the criteria for:

  1. Persistence (P).
  2. Bioaccumulation (B).
  3. Toxicity (T).


For a substance to be considered vPvB, it must meet the criteria for:

  1. Very high persistence (vP).
  2. Very high bioaccumulation (vB).


The CLP Regulation subsequently incorporated these properties as a specific hazard class, referred to as “persistent, bioaccumulative and toxic or very persistent and very bioaccumulative properties”.


Under CLP, a PBT substance is one that meets the criteria for persistence, bioaccumulation and toxicity, whereas a vPvB substance is one that meets the criteria for very high persistence and very high bioaccumulation.


  1. The classification criteria include, among other things, values relating to degradation half-lives in water, sediment and soil, as well as the bioconcentration factor. The assessment must take into account the available scientific information as a whole and apply a weight-of-evidence approach. Commission Delegated Regulation (EU) 2023/707 – amendment of the CLP Regulation


Classification under the CLP Regulation


The CLP Regulation incorporates PBT and vPvB properties as a specific hazard class.


For substances:

  1. Application of the new classification criteria began, at the latest, on 1 May 2025.
  2. Substances already placed on the market before 1 May 2025 have a transitional period until 1 November 2026 to comply with these new requirements.


For mixtures:

  1. Application of the criteria began, at the latest, on 1 May 2026.
  2. Mixtures placed on the market before 1 May 2026 may benefit from a transitional period until 1 May 2028.


When a substance or mixture meets the criteria for this hazard class, CLP establishes specific hazard communication elements, including the following hazard statements:

  1. EUH440: “Accumulates in the environment and living organisms, including in humans”, for PBT properties.
  2. EUH441: “Strongly accumulates in the environment and living organisms, including in humans”, for vPvB properties.

Official source:

  1. Commission Delegated Regulation (EU) 2023/707 – CLP


What should be done?


Persistence and bioaccumulation mean that PBT and vPvB substances can remain in the environment and accumulate in organisms for long periods. Prevention should therefore focus primarily on avoiding their use and minimising emissions and exposure.


In workplaces, preventive risk management must follow the principles established in occupational health and safety legislation and in the specific legislation on chemical agents.


Where PBT or vPvB substances are present or used:


  1. Their presence must be identified and it must be determined how they are used, generated or released in the work process.
  2. The corresponding risk assessment must be carried out.
  3. Elimination or substitution of the substance should be prioritised whenever technically possible.
  4. Where substitution is not possible, measures must be implemented to prevent or reduce exposure, giving priority to collective protective measures over individual protective measures.
  5. Unnecessary emissions, discharges and releases into the environment must be avoided.
  6. The risk assessment and preventive measures must be kept up to date when working conditions change or new relevant information becomes available.



Occupational health and safety legislation establishes the obligation to protect the safety and health of workers against risks arising from work and to apply the principles of preventive action.


Official sources:


  1. Law 31/1995 on Occupational Risk Prevention – BOE
  2. Royal Decree 374/2001 on chemical agents at work – BOE
  3. INSST Technical Guide for the assessment and prevention of risks related to chemical agents – 2022


PBT, vPvB and other substances of concern


PBT and vPvB properties are not the only properties that may determine a high level of environmental concern.

The CLP Regulation also currently establishes a specific hazard class for persistent, mobile and toxic (PMT) and very persistent and very mobile (vPvM) substances. These substances have different characteristics from PBT and vPvB substances and must therefore be distinguished from them.

  1. The incorporation of these new hazard classes improves the identification and communication of environmental risks associated with substances that may persist and move through the environment. Commission Delegated Regulation (EU) 2023/707 – new CLP hazard classes


OSPAR

OSPAR considers hazardous substances to include those that are persistent, liable to bioaccumulate and toxic (PBT), as well as substances giving rise to an equivalent level of concern.


OSPAR maintains a List of Chemicals for Priority Action and a List of Substances of Possible Concern. These lists are reviewed in the light of new scientific information and developments in European and international legislation.


OSPAR also develops measures aimed at reducing emissions and discharges of hazardous substances to the marine environment and promotes, among other measures, substitution, restrictions on use and best environmental practices.


Official sources:

  1. OSPAR – Hazardous Substances
  2. OSPAR – Chemicals Overview
  3. OSPAR – List of Substances of Possible Concern


Guidance


  1. Technical Guide for the assessment and prevention of risks related to chemical agents in the workplace. INSST, 2022

For information on PBT and vPvB substances, the official sources from ECHA, EUR-Lex and OSPAR indicated in this section should also be consulted.


Legislation


  1. Law 31/1995, of 8 November, on Occupational Risk Prevention – BOE
  2. Royal Decree 374/2001, of 6 April, on the protection of the health and safety of workers against risks related to chemical agents at work – BOE
  3. Regulation (EC) No 1907/2006 (REACH) – Annex XIII – EUR-Lex
  4. Regulation (EC) No 1272/2008 (CLP), as amended by Commission Delegated Regulation (EU) 2023/707 – EUR-Lex
  5. OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic
  6. OSPAR – hazardous substances and substances for priority action


References


  1. ECHA. PBT assessment list. Database for the assessment of PBT and vPvB properties. Information consulted in August 2026.
  2. ECHA / European Union. REACH Regulation, Annex XIII.
  3. European Union. Commission Delegated Regulation (EU) 2023/707, amending the CLP Regulation to introduce new hazard classes, including PBT and vPvB properties.
  4. OSPAR Commission. Hazardous Substances; Chemicals Overview; List of Substances of Possible Concern.
  5. INSST. Technical Guide for the assessment and prevention of risks related to chemical agents in the workplace. 2022.
  6. BOE. Law 31/1995 on Occupational Risk Prevention. Consolidated text, latest update published on 9 April 2026.
  7. BOE. Royal Decree 374/2001 on the protection of the health and safety of workers against risks related to chemical agents at work.



Last update August 2026