The UN published the 6th biannual revision of the Globally Harmonized System of Classification and Labeling (GHS) in June 2015. The amendments are given in a 32-page document, ST-SG-AC10-42a , and are summarized here.

The amendments to GHS primarily address “a new hazard class for desensitized explosives and a new hazard category for pyrophoric gases; miscellaneous provisions intended to clarify the criteria for some hazard classes (explosives, specific target organ toxicity following single exposure, aspiration hazard and hazardous to the aquatic environment); additional information to be included in the Safety Data Sheets (section 9); revised and further rationalized precautionary statements and a new example in Annex 7 addressing labelling of small packagings.”. 

Changes are discussed here in accordance with where each change is found in the GHS book, starting with the introduction section.

Introduction
A definition of desensitized explosives is added.

Clarification is made that in transport, GHS pictogram(s) not required by the UN Model Regulations on the Transport of Dangerous Goods, Model Regulations should only appear as part of a complete GHS label; they must not appear independently.

The content of Section 9 of the SDS in chapter 1.5 is replaced entirely. A note is added clarifying that the order may be followed but is not mandatory. Competent authorities may require an order that differs from the model regulation, or may leave it to the preparer of the SDS to order as they prefer.
 

Physical hazard classifications
Explosives:

• Explosives Division 1.6 are redefined as containing ‘predominantly’ instead of ‘only’ extremely insensitive substances or mixtures.
• Note 2 on the criteria for explosives clarifies types of desensitized explosives.
• Special provision 347 added to the decision logic in Figure 2.1.3: Procedure for assignment to a division in the class of explosives.
• In the guidance, the phrase ‘A substance or mixture is not classified as explosive if’ is updated to ‘The acceptance procedure for the hazard class “Explosives” need not be applied if’. This reflects the fact that a supplier cannot classify in the class explosives, but must propose this classification to competent authorities who authorize the transport and/or use of the explosive subject to specific conditions.
• The use of exothermic decomposition energy and exothermic decomposition temperature to exclude a material from the application of the acceptance procedure is clarified.

Flammable gases:

• The chapter title is returned to ‘Flammable gases,’ obsoleting the awkward class name ‘Flammable gases (including chemically unstable gases)’
• A new hazard category of ‘pyrophoric gas’ is inserted into the flammable gas chapter. A pyrophoric gas is ‘Flammable gas that ignite spontaneously in air at a temperature of 54 ºC or below.’ [Note: this differs from the definition of pyrophoric gas in the US OSHA and Canada GHS, which reads ‘a chemical in a gaseous state that will ignite spontaneously in air at a temperature of 130 degrees F (54.4 degrees C) or below.’
• Pyrophoric gas uses the flame pictogram and ‘Danger’ signal word and the H-statement ‘May ignite spontaneously if exposed to air’
• The Table 2.2.4 for label elements for flammable gases now adds pyrophoric gas besides ‘category A’ and ‘category B’ chemically unstable gases and links all three under a table cell indicating these are “additional sub-categories.”
• A note is added clarifying that classification and label elements for all applicable categories and sub-categories must be communicated.
• The logic for classification of pyrophoric gases is inserted and logic diagrams updated.
• The label elements for pyrophoric gases are:

The new P-statements corresponding to pyrophoric gas are:

• P222 - Do not allow contact with air
• P280 - Wear protective gloves/protective clothing/eye protection/face protection

Substances and mixtures which, in contact with water, emit flammable gas:

• The classification criteria for category 3 is changed from “equal to or greater than” to merely “greater than” 1 Liter. The decision logic is updated accordingly.

Desensitized explosives:

• An entire new chapter, 2.17, is added for the new hazard class “desensitized explosives.” This consists of 4 categories of “solid or liquid explosive substances or mixtures which are phlegmatized to suppress their explosive properties in such a manner that they do not mass explode and do not burn to rapidly and therefore may be exempted from the hazard class ‘explosives’.”
• The label elements for desensitized explosives are:

The new P-statements corresponding to desensitized explosives are:

• P210 - Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking
• P212 - Avoid heating under confinement or reduction of the desensitizing agent
• P230 - Keep wetted with .?
• P233 - Keep container tightly closed
• P280 - Wear protective gloves/protective clothing/eye protection/face protection
• [For categories 1 – 3:] P370 + P380 + P375 - In case of fire: Evacuate area. Fight fire remotely due to the risk of explosion
• [For category 4:] P371 + P380 + P375 - In case of major fire and large quantities: Evacuate area. Fight fire remotely due to the risk of explosion
• P401 - Store in accordance with:
• P501 - Dispose of contents/container to .?
   

Health hazard classifications
No new health hazards are added to GHS. No change to GHS mixture classification logic is required. Chapter 3 amendments address

• Addition of 460 (Fluorescein leakage (FL)) test method reference for eye corrosion/serious damage in chapter 3.3
• Deletion of reference to Mouse spot test (OECD 484) for germ cell mutagenicity in chapter 3.5
• Clarification by changing “ingredients” to “ingredient” in the table of cut-off values/concentration limits for classification of mixtures as reproductive toxicants and add a reference to OECD test number 443 in chapter 3.7
• A new paragraph 3.8.3.4.6 sets a relevance level of 1% for ingredients to be used in the additivity calculation for STOT SE 3 effects in chapter 3.8
• A relevance level of 1% is set for ingredients to be used in the additivity calculation for aspiration hazard in chapter 3.10. The text describing classification of mixtures is reworded for consistency but not substantively changed.

Environmental hazard classifications
No new environmental hazards are added to GHS. No change to GHS mixture classification logic is required. Chapter 4 amendments address

• In chapter 4.1 for aquatic hazards, a reference to OECD Test Guideline number 123 for bioaccumulation potential is added. Multiple clarifications are made that the ingredient concentration must be multiplied by the M-factor before any comparison with classification thresholds is performed.

Annex I
Annex I is updated with the insertion of the appropriate tables for pyrophoric gases and desensitized explosives.
 

Annex III
New or Revised P-statements
Annex III is updated with the insertion of the appropriate tables for pyrophoric gases and desensitized explosives.
New H-statements and P-statements created for the new pyrophoric gases and desensitized explosives hazard classes:

Annex IV

Section 9 of the SDS form and content guidance is entirely replaced in GHS Revision 6. The biggest impact for maintenance of SDS templates will certainly arise from the instructions that the competent authorities or supplier may choose to represent the data in section 9 in any order. Additional data is called for, when appropriate, and significantly more discussion about the quality and extent of data is given.
The guidance now groups the data into three tables:

• A4.3.9.1: Retains all the properties/characteristics that have been in section 9, as data that should be given if applicable and for which it should be stated when no information is available or the case is not applicable.
• A4.3.9.2: Lists properties/characteristics related to specific hazard classes that are not required data but may be useful to communicate
• A4.3.9.3: Lists further properties/characteristics that are not required but may be useful to communicate

A note emphasizes that “The properties in Tables A4.3.9.1, A4.3.9.2, and A4.3.9.3 may be presented with or without any division (that is, as a list). Also the order of the properties may be adjusted if deemed appropriate.”

Annex VII

A new example of labelling of small packaging is given. The example addresses tiny ampoules supplied with reduced label elements on the plastic sleeve around each individual ampoule and full labelling on the outer package.

Annex IX

The references test methods for determination of aquatic hazards are updated.