Hazardous Substances 101

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We understand that managing your hazardous substances can be a seriously daunting task. If you’re new to the role or have been given the role of improving this area of the workplace, then don’t stress – this article has been put together for you.

Using a combination of our own information, and resources from the WorkSafe website, this is a high level but important overview for those starting out in hazardous substance management.


Storing hazardous substances safely is an important part of protecting you and the environment that you work in. This includes storing only what you need, ensuring that incompatible substances are not stored together, and that decanted substances are stored in the correct type of container and labelled accordingly.

Where and how you store those hazardous substances is critical, and this will depend on both the class of substance and the quantity. Smaller amounts could be stored in approved storage cabinets, whereas larger amounts may need to be kept outdoors in dedicated outdoor bulk stores. In these instances, you may also need to keep them a certain distance from other premises, or public places.

Knowing your limits

Keep the amount of hazardous substances on site to a practical minimum. This will make it easier to manage what you have and will likely reduce your compliance costs. Keep containers closed whenever possible to keep vapours contained, and to limit the chance of a spill incident.

Signage and labelling

Depending on the types and amounts of hazardous substances at your workplace, you may need safety signage to warn employees, contractors, and visitors to your site that these substances are present. On the containers that hold these substances, the labels must be legible and accurately reflect the contents inside.

Visit these Worksafe links for further information specific to signage and labelling

Knowing how to store your substances

First, take a look at the safety data sheet for each substance, sometimes referred to the MSDS or SDS. These are mandatory for each hazardous substance that you use, store or handle at your workplace and are to be provided by the substance manufacturer or distributor. The SDS will outline the hazards specific to that substance, tell you how to store it safely and which other substances or materials it should be kept away from.

Smaller amounts of flammable or corrosive substances can be stored in an approved storage cabinet. Larger amounts may have to be stored in purpose-built rooms indoors, or dedicated dangerous goods (DG) stores outdoors (the latter will often be a more practical option).

Many substances will require secondary containment – sometimes referred to as ‘bunding’ – over a certain storage threshold. There are a number of secondary containment options available and we have a dedicated article here that gives more details as to when it is required. 

Some types of substances have special rules. Take flammable substances as a case in point, the vapours from these can cause a fire or explosion if accidentally ignited. For your workplace, you need to remove ignition sources such as flames, sparks and other heat sources where these substances are used and stored. You may also need to ensure adequate ventilation is provided to prevent a build-up of vapours. 

Is certification required? 

If you have flammable, oxidising, toxic or corrosive substances at your workplace above certain quantities, you may need a location compliance certificate to certify that these substances are stored safely and according to the rules. WorkSafe have an excellent hazardous substances calculator that will confirm if you are over those thresholds, and therefore need one of these certificates or not.

What is meant by incompatible substances?

Not all hazardous substances can be located together safely. Different types of substances can cause a fire, explosion, or chemical reaction if they come into contact with each other. The SDS for each substance should detail what other substances needs to be kept separate from it but our dedicated chart gives a broad overview of incompatibles, as well as a one dedicated to Class 8 Corrosive substances.

Transferring or decanting hazardous substances

Try and keep your hazardous substances in the containers or drums that they originally arrived in. These containers will be safe, suited to the product inside and labelled correctly. However, there will be times when you will need to decant these substances into smaller containers for ease of use, or to mix substances in process containers before using them. While these will seem like straight forward tasks, the associated risks need to be understood – which the relevant SDS will help determine.

Containers holding hazardous substances must be in sound condition and made of a material that is suitable for containing the substance for as long as it is required.

An important consideration is ensuring that containers normally (or previously) used for food or beverages, are not used for hazardous substance storage or transfer, so they are not mistaken as such.

Do I need to be a ‘certified handler’?

Some substances are so hazardous that they are restricted from use by anyone, other than a specially trained person that is designated as a ‘certified handler’. WorkSafe have a dedicated section related to certified handlers, and when you need one onsite.
However even substances that no longer have certified handler requirements still need to be kept away from people not trained to work with them. Only personnel permitted by the business or authorised authority will be allowed to access these.

For more information on hazardous substances, visit the WorkSafe website here.

Creating safer working environments

At Hazero our mission is zero hazards. Our extensive range of quality products will help you store, contain and control and clean-up dangerous goods and hazardous substances.

View our full range of Chemshed Cabinets here.

Need help creating a safer working environment? Contact our team today on 0800 688 844 or email us at info@hazero.co.nz. Our team are also available for on-site assessments across New Zealand, click here to request a site visit.

Content above falls under the Hazero Disclaimer, for more information click here.


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