Key Summary: Substances of Very High Concern (SVHCs) are chemicals formally identified by ECHA under Article 57 of the REACH Regulation (EC 1907/2006) as posing the most serious risks to human health or the environment. The REACH Candidate List currently contains over 230 SVHCs and is updated twice per year. SVHCs include CMR substances (Category 1A/1B), PBT substances, vPvB substances, endocrine disruptors, and substances of equivalent concern. Once listed, suppliers must communicate safe-use information and notify ECHA if products contain SVHCs above 0.1% w/w. SVHCs may ultimately be placed on the Authorization List (Annex XIV), requiring explicit authorization for continued use. In the Netherlands, the RIVM maintains the broader ZZS list.
Substances of Very High Concern (SVHC) occupy a special position in European chemicals regulation. Identified under the REACH Regulation (EC 1907/2006), these substances pose the most serious risks to human health or the environment and are subject to increasingly restrictive regulatory measures — from notification obligations through to potential market bans. For occupational hygienists, understanding the SVHC framework is essential because these substances often overlap with workplace hazard priorities and trigger specific compliance requirements.
What Are SVHCs?
An SVHC is a substance that has been formally identified by ECHA (European Chemicals Agency) as meeting one or more of the criteria set out in Article 57 of the REACH Regulation. Once identified, SVHCs are placed on the Candidate List for authorization — a publicly available register that currently contains over 230 substances and is updated twice per year (typically in January and July).
The SVHC designation signals that the substance is under heightened regulatory scrutiny and may eventually be placed on the Authorization List (Annex XIV), which would require companies to obtain specific authorization before continuing to use or market the substance.
SVHC Categories
A substance can be identified as an SVHC if it meets any of the following criteria:
CMR Substances (Category 1A or 1B)
Substances classified as carcinogenic, mutagenic, or reprotoxic under Category 1A or 1B of the CLP Regulation. These are substances that are known or presumed to cause cancer, genetic defects, or reproductive harm. For a detailed discussion of CMR classifications and employer obligations, see our CMR substances guide.
PBT Substances
Substances that are simultaneously Persistent, Bioaccumulative, and Toxic. PBT substances do not break down readily in the environment, accumulate in living organisms, and are toxic. Because they persist and accumulate, even small releases can lead to increasing concentrations over time, making them difficult to manage once released.
vPvB Substances
Substances that are very Persistent and very Bioaccumulative. The criteria for vPvB are even more stringent than for PBT — the substance must be extremely resistant to degradation and accumulate strongly in organisms. vPvB substances are of concern because their long-term effects are inherently difficult to predict.
Endocrine Disruptors
Substances that interfere with the hormonal (endocrine) system and are likely to cause adverse effects in humans or wildlife. Endocrine disruptors can affect reproduction, development, and immune function at very low concentrations, making traditional dose-response approaches less applicable.
Equivalent Concern
Substances for which there is scientific evidence of probable serious effects to human health or the environment that are equivalent in concern to the categories above, but which do not fit neatly into the PBT, vPvB, or endocrine disruptor criteria. This catch-all category allows ECHA to address emerging hazards.
The Identification Process
The process for identifying a substance as an SVHC follows a defined procedure:
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Proposal: An EU Member State or ECHA (at the request of the European Commission) prepares an Annex XV dossier proposing the substance for SVHC identification.
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Public consultation: The proposal is published on ECHA’s website for a 45-day public consultation period, during which interested parties can submit comments.
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MSC agreement: The Member State Committee (MSC) discusses the proposal. If the MSC reaches unanimous agreement, the substance is identified as an SVHC.
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Candidate List inclusion: Once identified, the substance is added to the Candidate List for authorization.
From the Candidate List, substances may subsequently be recommended by ECHA for inclusion on the Authorization List (Annex XIV). Substances on the Authorization List require companies to apply for and obtain authorization to continue using them after a specified sunset date.
The Dutch ZZS List
In the Netherlands, Substances of Very High Concern are known as Zeer Zorgwekkende Stoffen (ZZS). The ZZS list is maintained by RIVM (Rijksinstituut voor Volksgezondheid en Milieu — National Institute for Public Health and the Environment) and goes beyond the ECHA Candidate List.
The ZZS list includes:
- All substances on the ECHA Candidate List (SVHCs)
- All substances on the REACH Authorization List (Annex XIV)
- Substances classified as CMR Category 1A or 1B under CLP that are not yet on the Candidate List
- Substances meeting PBT or vPvB criteria identified through other processes
- Substances identified as endocrine disruptors under the EU Biocidal Products Regulation or Plant Protection Products Regulation
Additionally, RIVM maintains a list of “potential ZZS” (pZZS) — substances that have indications of meeting ZZS criteria but have not yet been formally identified. This provides an early warning system for companies and regulators.
The ZZS concept is particularly relevant in environmental permitting in the Netherlands. Companies that emit ZZS substances must demonstrate that emissions are minimized and must work toward zero emissions. This creates a direct link between chemical regulation and occupational hygiene — substances that are ZZS often require enhanced workplace controls as well.
Implications for Workplaces
The SVHC/ZZS designation has several practical implications for workplace management:
Notification and Communication
Suppliers of articles containing SVHCs above 0.1% w/w must communicate this information down the supply chain. Recipients of such articles have the right to request SVHC information. For workplaces, this means that safety data sheets and workplace instructions may need to specifically address the SVHC status of materials in use.
Authorization Requirements
Once a substance moves from the Candidate List to the Authorization List, companies must obtain authorization to continue using it. The authorization application must demonstrate that risks are adequately controlled or that the socioeconomic benefits outweigh the risks. This can directly affect production processes and workplace practices.
Substitution Pressure
The entire SVHC/authorization framework is designed to drive substitution. Companies are encouraged — and increasingly required — to replace SVHCs with safer alternatives. For occupational hygienists, this creates opportunities to reduce workplace exposures but also requires vigilance to ensure that replacement substances do not introduce new hazards.
Link to Workplace Exposure Limits
Many SVHCs are also substances for which workplace exposure limits exist. The SVHC designation does not establish a new exposure limit, but it adds urgency to exposure management. Where both an SVHC designation and a DNEL or OEL exist, the occupational hygienist must consider both the compliance obligation (staying below the limit value) and the broader regulatory trajectory (potential restrictions or phase-out).
SVHC Data in DOHSBase
DOHSBase connects SVHC/ZZS information to the broader occupational health dataset:
- 5,300+ substances with REACH DNELs — many of these are substances also found on the Candidate List or that meet SVHC criteria
- Links to ECHA dossiers — direct access to the registration dossier information that underpins both DNEL values and SVHC identification
- GHS/CLP classification data — including the CMR classifications that form the largest category of SVHC identification, with H-statements and pictogram indicators
- Limit value hierarchy — showing where DNELs, OELs, and kick-off values sit for substances that are also SVHCs
This integrated approach means that when an occupational hygienist looks up a substance in DOHSBase, the complete regulatory picture is immediately visible — not just the exposure limit, but also the substance’s hazard classification, CMR status, and its position in the REACH regulatory framework.
For organizations managing chemical compliance across both workplace safety and environmental regulations, having SVHC/ZZS context alongside occupational exposure data in a single tool provides significant practical value.