 Commonwealth of Australia 2002

16.Recommendations

Limonene is classified as a hazardous substance by NOHSC, and listed under CAS number 138-86-3 and the names p-mentha-1,8(9)-diene and dipentene. The current EU classification, adopted in Commission Directive 98/73/EC, also classifies the chemical as a skin sensitiser, and this classification is due to be taken up in the next update of the NOHSC List of Designated Hazardous Substances. The classification also applies to CAS numbers 5989-27-5 and 5989-54-8 and to the names limonene, d-limonene and l-limonene, and has labelling note C. This assessment has not identified data contrary to the EU classification. Therefore it is recommended that the EU classification be adopted, including:

• 
  In addition to the current classification of X_i, R 38 (Irritating to skin) limonene also be classified as a skin sensitiser with the risk phrase
  
  R43 May cause sensitisation by skin contact

  This amendment should be taken up in the NOHSC List of Designated Hazardous Substances as soon as possible. Further information on classification and labelling is contained in Table 14.1. Limonene products containing ≥ 20% limonene are classified with risk phrases R38 and R43. Limonene products containing ≥ 1% & < 20% limonene are classified with risk phrase R43.

  
  
• 
  Recommended occupational safety phrases include:
  S2 – Keep out of reach of children
  S24 – Avoid contact with skin
  S37 – Wear suitable gloves
  S62 (only if classified as R65) – If swallowed, do not induce vomiting; seek medical advice immediately and show this container or label
  
• 
  Where limonene/dipentene or products containing it meets the criteria for aspiration hazard, the following risk phrase should be used:
  

  R65	Harmful: May cause lung damage if swallowed

• 
  Suppliers should ensure that commercially obtained natural extracts containing substantial amounts of limonene are classified to reflect this content. Examples of materials where the limonene content may not currently be acknowledged are “Terpenes and Terpenoids, orange-oil, CAS No 68647-72-3” and “Hydrocarbons, terpene processing by-product, CAS No 68956-56-9” (see Section 4).
  

It is recommended that NOHSC consider reviewing the general issue of classification of chemicals which may form hazardous products on storage, and if appropriate develop guidelines that will ensure consistent classification.

Recommendation 3: Prevention of formation of oxidation products

It is recommended that industry take steps to prevent as far as possible the formation of oxidation products in limonene/dipentene, throughout its life cycle. A combination of the following measures could be used towards this aim:

storage to minimise contact with air, light and heat;

correct choice of packaging;

addition of antioxidants;

precautions in handling;

monitoring of peroxide levels; and

use of expiry dates.

A model from one industry sector is the IFRA Guideline, which specifies that:

“d-, l-, and dl-limonene and natural products containing it should only be used when the level of peroxides is kept to the lowest practical level, for instance by adding antioxidants at the time of production. Such products should have a peroxide value of less than 20 millimoles peroxides per litre, determined according to the FMA method.” (see Appendix 5)

Recommendation 4: Workplace controls

It is recommended that workplaces manufacturing, handling or using limonene/dipentene, take note of the possibility of spontaneous flammability of used rags or other combustible material in contact with limonene, and of the explosive potential of limonene containing peroxides, when concentrated or distilled to dryness. Appropriate education and measures to control these hazards is recommended.

Engineering controls and safe work practices should be implemented to avoid dermal and inhalational exposure to limonene that may contain oxidation products, and to concentrations of limonene that may be irritating. NICNAS will prepare a Safety Information Sheet for limonene, for display in workplaces and highlighting appropriate control measures.

Recommendation 5: Hazard Communication

Suppliers of limonene/dipentene and products must comply with the NOHSC requirements for hazardous substances.

It is recommended that

Labels and MSDS be amended to incorporate the correct classification.

all manufacturers, suppliers and employers review their hazard communication, including MSDS compliance, paying particular attention to the following points:

• 
  correct identification of health hazards;
  
• 
  inclusion of all information relevant to the flammability hazards;
  
• 
  guidance to avoid spontaneous combustion of used rags or other combustible material;
  
• 
  guidance on the potential for explosion if peroxides are concentrated;
  
• 
  first aid advice, including the advice that vomiting should not be induced;
  
• 
  glove material suitable for the recommended uses; and
  
• 
  information on handling of spillages.
  

Although there are not sufficient data to classify limonene as an eye irritant under the NOHSC Approved Criteria for Classifying Hazardous Substances, it is recommended that MSDS include warnings on eye irritation, and guidance on eye protection, because eye irritation in rabbits has been reported.

Recommendation 6: ADG code

It is recommended that the Department of Transport and Regional Services (DOTARS) consider a submission to the UN to include d-limonene under the same UN code as dl-limonene, for consistency.

Recommendation 7: Initial Emergency Response Guide

It is recommended that Standards Australia consider whether UN2052 should be covered by the Initial Emergency Response Guide 15, rather than Guide 14 as currently listed, on the basis of limonene’s lower (Packing Group III) flammability.

Recommendation 8: Patch testing of hand eczema patients

It is recommended that medical practitioners carrying out patch testing for allergy diagnosis consider inclusion of oxidised limonene in the test series.

Recommendation 9: Public health regulatory controls

It is recommended that the final PEC report be forwarded to the National Drugs and Poisons Schedule Committee for their consideration, due to concerns about irritation or sensitisation in products containing higher concentrations of limonene.

The adoption of IFRA guidelines would remove the sensitisation hazard in those product covered by these guidelines.