WorkSafe New Zealand identifies three core duties: record all hazardous substances at the workplace, keep the inventory current, and make it available to emergency service workers. A good inventory helps a business understand what is on site, identify the controls that apply, and plan for spills, fires and exposure emergencies.
What is a hazardous substance inventory?
An inventory is a site-specific list of hazardous substances and hazardous waste used, handled, manufactured or stored at a workplace managed or controlled by a person conducting a business or undertaking (PCBU). It can also help workers, managers, compliance certifiers and health and safety inspectors understand the chemical risks present.
What information must it contain?
For every hazardous substance, WorkSafe says the inventory must include:
- the substance or product name and UN number, if one is available
- the maximum quantity likely to be held at the workplace
- where the substance is located
- any specific storage and segregation requirements
- a current safety data sheet (SDS), or a condensed version of its key information
- hazardous waste held at the workplace.
Use the maximum quantity likely to be present—not annual purchasing totals or only the amount found on the day of inspection. This figure helps determine whether controls such as signage, emergency planning, secondary containment or certification may be triggered.
Make it readily accessible
“Readily accessible” means the information can be obtained without difficulty, whether it is kept in hard copy, electronically or in another usable form. Emergency responders must be able to access it during an incident and after the workplace has been evacuated. A digital register is useful, but consider whether it will still be accessible during a power, internet or device failure.
Prepare a separate inventory for every site
A business operating from several workplaces needs an inventory for each site it manages or controls. The information should match the substances and maximum quantities at that particular location. Farms should consider fuel tanks, chemical sheds, dairy sheds, workshops and other storage areas; trades should include workshops, vehicles and controlled job-site stores where applicable.
When should the inventory be updated?
The inventory does not need to be a daily stocktake. Update it when a substance is introduced or removed, its location changes, or the maximum quantity likely to be held changes. Each update is also a prompt to check whether storage, segregation, emergency arrangements and other controls remain suitable.
Do small quantities still count?
Yes. WorkSafe states that any quantity of a hazardous substance generally creates an inventory requirement. A limited exception applies to consumer products used in quantities and ways consistent with normal household use. A product does not automatically qualify just because it can be purchased from a retail store; workplace scale and manner of use matter.
Other exceptions
WorkSafe identifies specific arrangements for transit depots and certain laboratories. Transit depots must instead keep prescribed information about the products and quantities at the depot or transfer zone. Laboratories using hazardous substances for research and development, analytical testing or teaching are exempt from the general inventory requirement, although records are still required for tracked or unapproved substances.
A practical five-step approach
- Walk the workplace: check stores, cupboards, tanks, workshops, vehicles, temporary areas and waste locations.
- Identify each product: confirm the label, supplier, UN number where applicable, and a current matching SDS.
- Record maximum quantities and locations: use realistic peak holdings for each site.
- Check the controls: review storage compatibility, segregation, containment, signage, emergency equipment and certification triggers.
- Assign ownership: nominate a person and create purchasing, relocation and disposal triggers so the inventory stays current.
Tools and support
WorkSafe points businesses to the free Hazardous Substances Calculator, which can be used to build an online inventory and identify key requirements. You can also read the full WorkSafe hazardous substance inventory guidance.
How ChemMatrix can help
ChemMatrix can walk your workplace, identify overlooked substances and waste, organise SDS records, build a location-based inventory, and turn storage and emergency-control gaps into a prioritised action plan. The result is a practical system your workers can use and your business can keep current.