CHCS  Chemical Hazards Communication Society  Promoting the awareness of chemical hazards & improvements in their identification & communication

CHemical hazards Questions Forum 

CHCS runs an email-based discussion group, known as the Forum, for the mutual support of CHCS members and others with an interest in Chemical Hazard Communication.

With around two-thirds of the Forum subscribers being located in the EU, and around 80% of those in the UK, the Forum has had a natural bias towards European and UK issues. But with the introduction of GHS, and the magnitude of international trade – especially in mixtures – there are many product stewards outside the UK who consider it worthwhile to subscribe. At the last count, nearly a third of the subscribers were located outside of the UK in thirty-two different countries.

The CHCS email Forum generates significant interest, and is known to have a number of readers working for various regulatory bodies.

Subscribers have often been able to find help and guidance in areas where the regulatory framework is silent or unclear.

The Forum is free, is simple to join, and is open to anyone anywhere in the world who has a professional involvement in the subject of Hazardous Chemicals (Dangerous Goods) Communication.

The Forum is not a bulletin board, but a 'push' email system. Forum Subscribers submit their contributions by email to the Forum Operator: Questions, Responses, and News items. The only restriction in scope is that submissions should be relevant to Chemical Hazard Communication (CHC) matters.

The Forum Operator (ForOp), who also acts on behalf of CHCS as the primary moderator, then emails the content to each person on the subscription list. The subscription list is securely retained, and the addresses of other subscribers are not present in the emails received by the subscribers.

Examples of recent Questions from the Forum

Examples of recent Questions from the Forum with the various answers that reply directly and also draw out the different points involved are as follows:


Would anyone be able to advise the threshold limit levels for disclosing 2-Methyl imidazole (CASRN 693-98-1) in Section 3 of the SDS?


[Summary of responses]

Based on the REACH Registration dossier, and the proposed harmonised classification, the classification for the substance includes Repr 1B and Carc 2,

Both of these hazard categories result in a threshold for listing in the SDS as 0.1%, according to ECHA’s ‘Guidance on the compilation of safety data sheets’, p 47

That requirement assumes that the overall mixture is classified as hazardous according to CLP.

If the overall mixture is not classified according to CLP for any endpoint, and assuming it is not a gaseous mixture, then there is a general disclosure limit of 1% for hazardous ingredients in section 3 of the SDS: unless the substance happens to be PBT, vPvB or is listed on the Candidate list under “equivalent concern” basis (in which case 0.1% does apply).

With the imminent harmonised classification (14th ATP) of category 1B reprotoxicity, the mixture must be classified at 0.3% of 2-Methylimidazole; but if a mixture has less than 0.3% of this chemical and the mixture is not classified for any reason then legally it would not need to be disclosed. Reference REACH Annex II, 3.2.2


Does any quantity of broken package / spill of UN transport classified material need to be notified in every EU country (I have been told that it does in Finland)?

If so, is there a list of the authorities that coordinate this?


The incident reporting requirements are clearly defined in ADR

Depending on transport category, the reporting is required for spills greater than 50kg/50L (for Cat 0 or Cat 1) up to 1000kg/1000L (for Cat 4).

For trans-border transport ADR applies. But for local transport, local legislation can be more stringent.


Can anyone please comment on why Texanol (R):

2,2,4-trimethyl-1,3–pentanediol monoisobutyrate

CAS RN 25265-77-4

- is classified as a Category 2 Reproductive Toxicant in the USA?

This material is not classified as a Reproductive Toxicant by the European Chemicals Agency (ECHA):


[Summary of responses]

Texanol(R) is a commercial product. The Manufacturer's SDS shows that it contains 0.8% of the di-isobutyrate ester (EC 229-934-9, CASRN 6846-50-0). The di-isobutyrate ester is classified (inter alia) as Repr Cat 2, H361d

In the US, different concentration limits are used for the classification of mixtures for reproductive toxicity, compared to the EU (and other jurisdictions). In North America, mixtures containing reproductive toxins of Cat 1A/1B/2 are classified for this effect at a concentration of 0.1%, compared to 0.3% for Cat 1A/1B and 3% for Cat 2 in the EU.

This difference arises from the GHS, where both sets of concentration limits are given with the option for jurisdictions to choose which to use.

In US (and Canada), they have chosen to implement the lower concentration limit as the classification threshold. In most other jurisdictions the higher concentration limits are used as the classification threshold, with a note added to the classification tables, requiring disclosure of the ingredient on the SDS where the substance is present at or above the lower concentration limit.

There are similar issues for sensitisers, carcinogens and STOTS.

Subscribing to the Questions Forum 

Anyone joining CHCS will be automatically subscribed to the Forum, and need take no further action. You can download the Forum's "Conditions" from this link: CHCS Email Forum Conditions.

A non-member of CHCS wishing to subscribe to the Forum should send an email with the Subject "Forum Join", to

Please do not include any questions or other Forum content in the message. It will be ignored.

In the message, please give your name as you usually write it. The forename(s) and surname which you give will be into our database and will be shown at the head of any contributions (questions, responses, news) from you that are published as Forum messages.

You will be sent a message requesting consent for CHCS to process your personal information. Without that consent we cannot send you the messages.

Once your consent has been recorded, you will be sent a confirmation message with details on how the Forum operates.

CHCS will record, store, and use for sending the Forum messages, the email address from which the “Forum Join” message was sent. Requests to subscribe a third party cannot be accepted.

Changes of your email address should be sent to and the same rules will apply. An address change request may be subjected to a confirmatory check. Only one address per subscriber may be active at a time. If any email address is reported as no longer valid, it may be automatically deleted. In that case you will need to subscribe again from your new address.

When you leave the Forum, please notify Your personal data will be deleted on receipt of that notification.

Please feel free to mention the Forum to others whom you feel may be interested. Membership of CHCS is a not a requirement for becoming a Forum subscriber.

We look forward to receiving your request to join our Forum.


  1. CHCS reserves the right to terminate the Forum at any time.

  2. Whilst CHCS in general and the operator of the Forum in particular will use their best endeavours to ensure the accuracy and legality of the information transmitted the Forum messages do not create any liability or responsibility in any way for CHCS and/or its officers and members.

  3. The name of the originating subscriber is shown at the start of each contribution. The name used will be that held in the Forum address book, which will be as set out in the request to join.

  4. The Forum is not a bulletin board. You can only see the messages if your email address is on the subscription list held by the Operator.

  5. The forum is run by a CHCS volunteer. No service guarantee can be assumed or is given.

For further information on CHCS or the Forum please contact the CHCS Office.

No Messages?

The Forum is not an automated bulletin-board, but is a manual email messaging system involving real human beings. Nonetheless the Forum does not take many breaks. Any break longer than around four days would usually be announced in advance. So if you have seen no messages for a week or more, a filter or other gatekeeper at your end may be blocking the messages.

If you are a Forum subscriber whose message flow has dried up, please email the Forum Operator at to check; but you will need to provide an alternative contact channel for the ForOp to use to respond. (Because otherwise the email reply to your enquiry will fall into the same pit as the Forum messages themselves!)


Webinar: Introduction to Chemical Regulation in Japan, Incorporating the Latest Updates to GHS
14 September 2022, 14:00 - 15:15
. This webinar will be of interest to organisations involved in supplying chemicals to Japan, to companies with affiliates or customers in Japan, and to anyone who is interested in the Japanese regulatory system. See CHCS Events page. 

CHCS announce the 11th Annual Lectures
28 September 2022, Windmill Village Hotel, Birmingham Road, Allesley, Coventry
, CV5 9AL. Registration is now open for our members. See CHCS Events page. 

CHCS' July 2022 Newsletter is now available, containing several important updates on the many recent changes to the regulation framework. See CHCS July 2022 Newsletter. 

UK REACH - Consultation on Extending Submission Deadlines for UK REACH Transitional Registrations
In December 2021 Defra committed to exploring alternative arrangements for transitional registrations in order to support chemical businesses, whilst upholding a high level of human and environmental health protection in line with our international commitments. CHCS members can read more on our News Briefings page. [Posted on 11 July 2022]

European Union Harmonised Classification and Labelling Proposals, Public Consultation Open
Consultations have opened on several substances subject to EU harmonised classification and labelling proposals (CLH). CHCS members can read more on our News Briefings page. [Posted on 7 July 2022]

UK Latest GB Mandatory Classification and Labelling Agency Opinions
The UK Agency for CLP, the Health & Safety Executive (HSE), published a further 59 Mandatory Classification and Labelling (MCL) Opinions last month, which are applicable in Great Britain (GB). CHCS members can read more on our News Briefings page. [Posted on 5 July 2022]

UK REACH - Updating the UK Authorisation List (Annex 14)
The Department for Environment, Food and Rural Affairs (Defra) has published a call for evidence in relation to the inclusion of substances in Annex 14 of UK REACH. CHCS members can read more on our News Briefings page. [Posted on 4 July 2022]

Annex VIII of GB CLP - Update
Despite the Government’s intention not to retain Annex VIII of the EU’s Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulations in UK law, we have been informed that Annex VIII has been inadvertently retained following the UK’s exit from the EU.  CHCS members can read more on our News Briefings page. [Posted on 23 June 2022]

ECHA Calls For Evidence On Skin Sensitisers In Consumer Mixtures
The European Chemical Agency (ECHA) are calling for evidence on skin sensitisers in consumer mixtures. The scope of the investigation comprises substances fulfilling the criteria for classification as skin sensitisers as defined by the CLP Regulation (Regulation (EC) 1272/2008) in mixtures marketed or available for consumers in the EU/EEA. CHCS members can read more on our News Briefings page. [Posted on 21 June 2022]

Revocation Of The Misuse Of Drugs (Amendment) (England, Wales And Scotland) Regulations 2021 In Relation To Gamma Butyrolactone And 1,4-Butanediol
The amendment to the Misuse of Drugs Act that was due to come into force on 15th June 2022 has been revoked. CHCS members can read more on our News Briefings page. [Posted on 26 May 2022]

The Department For Transport Has Issued A Call For Evidence
The Department for Transport has issued a Call for Evidence in relation to the Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations 2009 and the RID / ADR 2021 amendments. CHCS members can read more on our News Briefings page. [Posted on 13 May 2022]

Webinar: Poly- And Perfluoroalkylated Substances (PFAS): The Gathering Storm For Chemical Regulatory Professionals, And The Industry
The presentation and recording from our webinar held on 21 April 2022 are now available to members linked from the Past Events page of our website.[Posted on 22 April 2022]

The European Commission Has Issued A Call For Evidence
The European Commission has issued a Call for Evidence on an initiative to streamline EU-level scientific and technical work on chemicals. CHCS members can read more on our News Briefings page. [Posted on 4 April 2022]

Webinar: The Regulation Of Endocrine Disruptors In The European Union
The presentation and recording from our webinar held on 29 March 2022 are now available to members linked from the Past Events page of our website. [Posted on 31 March 2022]

Poison Centres Portal - Lichtenstein Connects
The poison centre for Lichtenstein has announced that they are now connected to the poison centre portal. CHCS members can read more on our News Briefings page. [Posted on 22 March 2022]

ECHA Is Developing A New Chesar Platform
A Questionnaire has been issued by ECHA for interested parties to join a stakeholder group. CHCS members can read more on our News Briefings page. [Posted on 3 March 2022]

Webinar: Food Contact Materials Regulation In China
The presentation and recording from our webinar held on 23 February 2022 are now available to members linked from the Past Events page of our website. [Posted on 24 February 2022]

The European Chemicals Agency Is Looking For Stakeholder Input On IUCLID Published Data
The European Chemicals Agency, ECHA has launched a survey on their new ‘Data Availability’ solution. CHCS members can read more on our News Briefings page. [Posted on 14 February 2022]

DEFRA Surveys On The Provisions Of Article 33, UK REACH
The Department for Environment, Food and Rural Affairs (DEFRA) is inviting GB-based suppliers and retailers of articles to contribute to a survey regarding Article 33 of UK REACH. CHCS members can read more on our News Briefings page. [Posted on 11 February 2022]

Changes To The Misuse Of Drugs Act: Gamma Butyrolactone And 1.4-Butanediol
Following the recommendations of the UK Advisory Council on the Misuse of Drugs, tighter controls are being placed on gamma butyrolactone (GBL) and 1,4-butanediol (1,4-BD). CHCS members can read more on our News Briefings page. [Posted on 11 February 2022]

Multilateral Agreement M345
The United Kingdom has countersigned Multilateral Special Agreement 345 concerning the transport of UN 2672 ammonia solution in IBCs with a vapour pressure of more than 110 kPa (1.1 bar) at 50oC or 130 kPa (1.3 bar) at 55oC. This is under ADR under paragraph 1.5.1 of ADR. CHCS members can read more on our News Briefings page. [Posted on 8 February 2022]

NPIS Announces That Annex VIII Of EU/GB CLP 1272/2008 Applies In The UK From Jan 1st 2021
The National Poisons Information Service (NPIS) the poison centre for GB and NI has announced that Annex VIII of EU/GB CLP 1272/2008 applies in the UK from Jan 1st 2021. CHCS members can read more on our News Briefings page. [Posted on 4 February 2022]

Endocrine Disruptors - 1st CHCS Video
We have produced our first video for members: "Endocrine Disruptors", which is available to members free-of-charge.

This introductory video explains the various components of the human endocrine system and how they interact, to help understand the mechanisms of endocrine disruptors on human systems.

The video is just over 10 minutes long.

To register for access to the video, please visit our video registration page: Endocrine Disruptors Video Registration.

[Posted on 1 July 2019]

CHCS News Summary
  • Poison Centres Portal - Belgium Connects
    (24 January 2022)

  • Revision Of The REACH Regulation
    (20 January 2022)

  • EAC Corrigendum Published
    (17 December 2021)

  • Alternative Arrangements For UK REACH Registration Being Considered By Defra
    (6 December 2021)

  • CLP Annex VI Correction Published
    (17 November 2021)

  • Model Regulations, 22nd Revised Edition
    (1 November 2021)

  • The Deadline To Submit A Downstream User Notification (DUIN)
    (26 October 2021)

  • The Carriage Of Dangerous Goods And Use Of Transportable Pressure Equipment Regulations Amendments Now Combined
    (21 October 2021)

  • The Carriage Of Dangerous Goods And Use Of Transportable Pressure Equipment Regulations 2009 Amended
    (21 October 2021)

  • ECHA - Safer Chemicals Recordings Available
    (20 October 2021)

  • GHS Revision 9
    (20 September 2021)

  • UK Cosmetics Regulation
    (1 September 2021)

  • MLA 340 And RID 06/2021 Counter-Signed By The United Kingdom
    (20 August 2021)

  • Publication Of The Draft 18th ATP To The CLP Regulation
    (17 August 2021)

  • Dangerous Emails Disguised As Coming From NPIS
    (29 July 2021)

  • SDS Will Be The Focus For Enforcement In 2023
    (20 July 2021)

  • Government Updates Their Guidance On Poison Centres
    (29 June 2021)

  • Inception Impact Assessments (Roadmaps) For REACH & CLP - deadline 23:00 GMT
    (31 May 2021)

  • Poison Centre Practical Guide updated
    (20 May 2021)

        CHCS Members can read these News items, and older posts, on the CHCS News Briefings page.

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