Categorisation of highly branched organic chemicals

Who should read this and when?

Importers and manufacturers of industrial chemicals (and products that are designed to release industrial chemicals) that are highly branched organic chemicals. This guidance will help you work out whether your introduction will be an exempted, reported or assessed introduction. This information should be read before the chemical is introduced in Australia. You must read this in conjunction with the categorisation guide.

What is a highly branched organic chemical?

Highly branched organic chemicals are industrial chemicals that are carbon based, are not polymers, and are branched at:

• more than one tertiary carbon, or
• more than one quaternary carbon, or
• a combination of tertiary and quaternary carbons.

Chemicals that are highly branched can be very resistant to biodegradation and can persist in the environment long after release.

Your introduction is a ‘specified class of introduction’ if it is a highly branched organic chemical.

We have an increased level of concern for specified classes of introductions, due to a greater potential for particular hazards or high levels of human or environmental exposure. For this reason, there may be additional or different requirements when working out your category of introduction as well as additional record keeping obligations.

Our increased level of concern for introduction of chemicals that are highly branched organic chemicals is because this class of chemicals are difficult to model and are often persistent in the environment. We outline the additional or different requirements arising from these concerns below.

Is your introduction exempted, reported or assessed?

You must work out if your your introduction meets the criteria for the exempted or reported categories by following steps 1-6 of the categorisation guide. If your introduction does not meet the criteria for the exempted or reported categories, it will be an assessed introduction (unless you meet the criteria for a commercial evaluation authorisation).

You can find the additional or different requirements to be aware of when working out your introduction category at:

• Step 5.4: Work out your environment hazard characteristics

When working out hazard characteristics for a highly branched organic chemical in environment hazard bands, you will need to demonstrate that your chemical does not have certain environment hazard characteristics. To demonstrate that a highly branched organic chemical does not have the environmental persistence hazard characteristic, you will need to have studies performed using the chemical itself and you cannot use in silico predictions or read across information.

If your chemical is a persistent, highly branched organic chemical, you will need to have in vivo chronic aquatic toxicity studies performed on your chemical (or suitable read across information). Acute aquatic toxicity data is not sufficient to categorise persistent highly branched chemicals.

Information you need to demonstrate that your chemical does not have environment hazard characteristics

Persistence

You’ll need additional or different information to show your highly branched chemical does not have the persistence part of the following environmental hazard characteristics:

• persistent, bioaccumulative and toxic - Environment hazard band D

• persistent and bioaccumulative - Environment hazard band C

• bioaccumulation potential – Environment hazard band A

• industrial chemical (other than a polymer) that does not meet the criteria for ready biodegradability - Environment hazard band A

You cannot use in silico predictions or read across information to demonstrate the absence of persistence for highly branched chemicals.

Persistent, bioaccumulative and toxic – Environment hazard band D

For the indicative environment risk of your introduction to be low, you need to show that your chemical doesn’t have this hazard characteristic. If your introduction is in environment exposure band 2 (and you want to demonstrate that it has very low indicative environment risk), or if the environment exposure band is 3 or 4, you might choose to demonstrate the absence of the persistent, bioaccumulative and toxic hazard characteristic by demonstrating the absence of the persistence hazard characteristic.

To do this, you’ll need:

• a test result from a study on the chemical, conducted following an acceptable test guideline for ready biodegradability, which meets at least one of the following degradation pass levels during the period specified in the test method:
  • tests based on dissolved organic carbon (DOC) – greater than or equal to 70% DOC removal, or
  • tests based on carbon dioxide generation – greater than or equal to 60% theoretical carbon dioxide, or 
  • tests based on oxygen depletion – greater than or equal to 60% theoretical oxygen demand,

or

• a test result from a study on the chemical, conducted following an acceptable test guideline for transformation in aquatic sediment systems, results in both:
  • a degradation half-life in water of less than 2 months, and
  • a degradation half-life in sediment of less than 6 months

Persistent and bioaccumulative – Environment hazard band C

You might choose to demonstrate the absence of the persistent and bioaccumulative hazard characteristic by demonstrating the absence of the persistence hazard characteristic.

To do this, you’ll need:

• a test result from a study on the chemical, conducted following an acceptable test guideline for ready biodegradability, which meets at least one of the following degradation pass levels during the period specified in the test method:
  • tests based on dissolved organic carbon (DOC) – greater than or equal to 70% DOC removal, or
  • tests based on carbon dioxide generation – greater than or equal to 60% theoretical carbon dioxide, or 
  • tests based on oxygen depletion – greater than or equal to 60% theoretical oxygen demand,  

or

• a test result from a study on the chemical, conducted following an acceptable test guideline for transformation in aquatic sediment systems, results in both:
  • a degradation half-life in water of less than 2 months, and 
  • a degradation half-life in sediment of less than 6 months

Bioaccumulation potential – Environment hazard band A

To demonstrate the absence of this hazard characteristic, you’ll need:

• a test result from a study on the chemical, conducted following an acceptable test guideline for ready biodegradability, which meets at least one of the following degradation pass levels during the period specified in the test method:
  • tests based on dissolved organic carbon (DOC) – greater than or equal to 70% DOC removal, or
  • tests based on carbon dioxide generation – greater than or equal to 60% theoretical carbon dioxide, or 
  • tests based on oxygen depletion – greater than or equal to 60% theoretical oxygen demand.

Industrial chemical (other than a polymer) that does not meet the criteria for ready biodegradability – Environment hazard band A

To demonstrate the absence of this hazard characteristic, you’ll need:

• a test result from a study on the chemical, conducted following an acceptable test guideline for ready biodegradability, which meets at least one of the following degradation pass levels during the period specified in the test method:
  • tests based on dissolved organic carbon (DOC) – greater than or equal to 70% DOC removal, or
  • tests based on carbon dioxide generation – greater than or equal to 60% theoretical carbon dioxide, or 
  • tests based on oxygen depletion – greater than or equal to 60% theoretical oxygen demand.  

Toxicity

If your highly branched organic chemical is persistent, you’ll need additional or different information to demonstrate that your chemical doesn’t have toxicity to any aquatic life as part of the following environment hazard characteristics:

• persistent, bioaccumulative and toxic - Environment hazard band D 

• very toxic to aquatic life - Environment hazard band C

• toxic to aquatic life - Environment hazard band B

• harmful to aquatic life - Environment hazard band A

You cannot use in silico predictions to demonstrate the absence of aquatic toxicity for persistent highly branched organic chemicals - only in vivo chronic toxicity studies conducted according to approved test methodology are acceptable. To see information you need for other environment hazard characteristics, follow step 5.4 of the categorisation guide.

Persistent, bioaccumulative and toxic - Environment hazard band D

For the indicative environment risk of your introduction to be low, you need to show that your chemical doesn’t have this hazard characteristic. If your introduction is in environment exposure band 2 (and you want to demonstrate that it has very low indicative environment risk), or if the environment exposure band is 3 or 4, you might choose to demonstrate the absence of the persistent, bioaccumulative and toxic hazard characteristic by demonstrating the absence of the aquatic toxicity hazard characteristic.

To do this, you’ll need test results for all 3 trophic levels (fish, invertebrates and algae) from in vivo studies on the chemical or from suitable read-across information, conducted following acceptable test guidelines for chronic aquatic toxicity with a NOEC or EC10 greater than 0.1mg/L for all 3 trophic levels.  

Very toxic to any aquatic life - Environment hazard band C

To demonstrate the absence of this hazard characteristic you’ll need test results for all 3 trophic levels (fish, invertebrates and algae) from in vivo studies on the chemical or from suitable read-across information, conducted following acceptable test guidelines for chronic aquatic toxicity with the following results for all 3 trophic levels:

• NOEC or EC10 greater than 0.1mg/L (for chemicals that are not readily biodegradable), or 
• NOEC or EC10 greater than 0.01mg/L (for chemicals that are readily biodegradable).

Toxic to any aquatic life - Environment hazard band B

To demonstrate the absence of this hazard characteristic, you’ll need test results for all 3 trophic levels (fish, invertebrates and algae) from in vivo studies on the chemical or from suitable read-across information, conducted following acceptable test guidelines for chronic aquatic toxicity with the following results for all 3 trophic levels: 

• NOEC or EC10 greater than 1mg/L (for chemicals that are not readily biodegradable), or 
• NOEC or EC10 greater than 0.1mg/L (for chemicals that are readily biodegradable).

Harmful to any aquatic life - Environment hazard band A

To demonstrate the absence of this hazard characteristic, you’ll need test results for all 3 trophic levels (fish, invertebrates and algae) from in vivo studies on the chemical or from suitable read-across information, conducted following acceptable test guidelines for chronic aquatic toxicity with the following results for all 3 trophic levels: 

• NOEC or EC10 greater than 1mg/L (for chemicals that are readily biodegradable).

Additional record keeping obligations 

There are no additional records that must be kept for this class of specified introduction. For record keeping requirements that apply to all chemical introductions see our guidance on compliance, reporting and record keeping obligations.  

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