Combustible liquids like diesel are not defined as ‘Dangerous Goods’ during transport, however, they are deemed to be ‘Dangerous Goods’ while they are being stored and handled. This means the Regulations apply, and set out how they must be stored and handled.

Polyethylene tanks currently available on the market may be used to store a variety of liquids such as diesel. Unlike steel alternatives, plastic tanks have limitations if subjected to fire. Polyethylene tanks have a relatively low melting point. In the event of a fire they are unlikely to be able to contain diesel stored. This can have a severe impact upon your property and the local landscape through soil and water contamination.

The risk and consequences of damage from a diesel spill increases with the volume being stored. An increasing number of large polyethylene tanks exceeding 10,000 L are known to have been manufactured and supplied for storing diesel on farms.

For farming purposes, polyethylene tanks are only acceptable for use on open land having an area greater than 2 ha. The maximum capacity of these tanks is 10,000 L. Refer to AS 1940 for further guidance.

To remain compliant with the Regulations and to minimise risk, follow these guidelines:

• Polyethylene tanks that have been manufactured to store diesel in quantities exceeding 10,000 L should not be used, even if you are storing less than 10,000 L. You need to prioritise the replacement of such tanks.
• Ensure diesel spills or leaks are able to be contained (e.g. bund) and cleaned up, refer to AS 1940 for further guidance.

Other things to consider when designing or reviewing your diesel storage area include:

• Locating the tanks outdoors and at least 15 m away from dwellings.
• Protecting them from the elements and impact (from vehicles on the farm).
• Securing tanks to prevent access by unauthorised people.

It’s worth noting that fuel distributors have a work health and safety duty to ensure people’s health and safety are not compromised. If you do have a polyethylene tank that exceeds 10,000 L, the fuel distributor may not refill that tank or may restrict the amount of fuel delivered.

Further guidance may be sought by emailing the Dangerous Goods Branch at dgsb@dmirs.wa.gov.au.