Hazard Warning Diamond Changes – Regulatory Deadline Approaches

Changes made to Hazard Warning Diamond labels in revised Edition of UN Model Regulations. All labels must be in compliance by 31st December 2016.

hazard warning diamond image

the Regulations

Packaged dangerous goods are transported across borders all over the world: hazardous chemicals shipped by sea in China may be re-loaded onto trains in Germany and transferred to trucks in France which are destined for the UK. For this reason, it was internationally agreed that safety standards must apply globally, and in order to uniform standards, reduce formalities, and facilitate transition from one mode of transport to another, a committee of experts was set up at the United Nations.

Their recommendations on the transport of dangerous goods were published in, what’s come to be known as, ‘The Orange Book’ and this consists of the ‘Model Regulations on the Transport of Dangerous Goods’ which covers many aspects including classification, transport documentation, marking, labelling and placarding.

Though not directly legally binding, these recommendations are addressed to governments and international organisations, such as IATA (Air), IMDG (Sea), ADR (Road) and RID (Rail) which are responsible for the regulations and legislation that ensure the safe transport of dangerous goods across different countries. The latest changes to warning diamonds stem from the amendments agreed in the 18th revised edition of the UN Model Regulations, and these were adopted and incorporated into the revisions of IATA, IMDG and ADR legislation.

Hazard warning diamond label SPECIFICATIONS

From 1st January 2015, every hazard warning diamond must conform to the following specifications:

  • Each label, whether printed on, or affixed to a package, must be durable and weather resistant. A label on a package must be able to withstand, without deterioration or a substantial change in color, a 30-day exposure to conditions that reasonably could be expected to be encountered by the labelled package

  • The label shall be in the form of a square, at an angle of 45° (diamond shape)

  • Minimum dimensions must be 100x100mm

  • The inner border line forming the diamond must now be at least 2mm thick 

  • The line inside the edge must be parallel and 5mm from the outside of that line to the edge of the label

  • The label should show a dotted outer boundary line (unless it is being applied on a background of contrasting colour)

  • If the size of the package so requires, the dimensions of the label and its features may be reduced provided the symbol and other elements of the label remain clearly visible. The solid line forming the inner border must remain 5mm from the outside edge of the label and the minimum width of the line must still be 2mm


The changes to hazard warning diamonds are minimal, but there is one significant modification to the inner border line which must now be a minimum width of at least 2mm.

Historically, most warning diamonds did not meet this new requirement.

The increase in the width of the border line was designed to help make the labels more pronounced and likely to attract attention, as illustrated below.

class 3 label with thin border imageclass 3 label with thick border image

For smaller packages, if a reduced size label is used, the border line must remain at least 2mm and also remain 5mm inside the outer edge of the label.

There is no specification for the inner border line width of 250mm placards, but it must be in approximate proportion to that shown in ADR (figure which would only give the inner border line a thickness of around 1.5mm. As the UN Model Regulations did not specify a minimum inner border line width for placards, neither has the IMDG Code, IATA or ADR.

There is also no specification for the thickness of the outer broken border line which is required when a label is placed on a non contrasting background.


Old labels, markings and placards can continue to be used until 31 December 2016.

Labels with a line thickness of less than 2mm are only acceptable until this date; after the deadline the new regulations will be mandatory.

From 1 January 2017, any package in transit must be labelled in accordance with latest regulations.


If you have pre-printed combination labels that contain a hazard warning diamond, you will need to check that these are in accordance with the latest regulations. Please contact us if you need further advice.

This article should not be used in substitute for checking the exact requirements in the applicable modal regulations. 

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