2.2 Naphthalene

2. Joint meeting of the Advisory Committee on Chemicals and Medicines Scheduling (ACCS/ACMS #20)

2.2 Naphthalene

On this page: Delegate's interim decision | Materials considered | Scheduling proposal | Background information for naphthalene

Delegate's interim decision

Materials considered

In making this interim decision, I have considered the following material:

• The application to amend the current Poisons Standard with respect to naphthalene;
• The public submissions received before the first closing date;
• The advice received from the Joint Advisory Committees on Medicines and Chemicals Scheduling (Joint ACMS-ACCS #20);
• The Australian Health Ministers' Advisory Council's Scheduling Policy Framework (SPF 2018); and
• Section 52E of the Therapeutic Goods Act 1989, in particular (a) the risks and benefits of the use of a substance; (b) the purposes for which a substance is to be used and the extent of use of a substance; (c) the toxicity of a substance; (d) the dosage, formulation, labelling, packaging and presentation of a substance; (e) the potential for abuse of a substance; and (f) any other matters that the Secretary considers necessary to protect public health.

Scheduling proposal

The pre-meeting scheduling proposal for naphthalene was published on the TGA website 31 August 2018 at Consultation: Proposed amendments to the Poisons Standard - ACCS, ACMS and Joint ACCS/ACMS meetings, November 2018.

Background information for naphthalene

In this section: Delegate's referral to ACCS-ACMS | Applicant's scheduling proposal and reasons | Current scheduling status | Scheduling history | Australian regulations | International regulations | Substance summary | Pre-meeting public submissions | Joint ACMS-ACCS advice

Delegate's referral to ACCS-ACMS

The chemicals scheduling delegate sought advice from the Joint Advisory Committee on Chemical Scheduling (ACCS) and Advisory Committee on Medicine Scheduling (ACMS) on a proposal to reschedule naphthalene from Schedule 6 to Schedule 7 in the Standard for the Uniform Scheduling of Medicines and Poisons (SUSMP) - the Poisons Standard.

Applicant's scheduling proposal and reasons

A private applicant submitted a proposal to reschedule naphthalene from Schedule 6 to Schedule 7.

The applicant's proposed amendments to the Poison Standard are:

The applicant's reasons for the request are:

• The sale of naphthalene to the public in the form of mothballs is an unacceptable risk. Reports of poisonings in Australia continue and there are regular enquiries to state Poisons Information Centres regarding mothball exposure.
• Sale of naphthalene has been banned in the EU and New Zealand.
• Inhalation of naphthalene vapours can cause toxic reactions and containment in a device that prevents ingestion will not prevent this.
• There are safer alternatives to naphthalene including camphor and 1,4-dichlorobenzene.

Current scheduling status

Naphthalene is currently listed in the Poisons Standard as follows:

Naphthalene is also subject to additional labelling and container requirements as outlined in Part 2 of the Poisons Standard as follows:

Scheduling history

February 1987, Drugs and Poisons Schedule Committee (DPSC)

In February 1987 the DPSC reviewed the toxicity of naphthalene in the domestic setting following a discussion of camphor at the November 1986 DPSC meeting. The committee agreed that no action was necessary as naphthalene was appropriately packed and labelled.

August 1989, DPSC (#54)

In August 1989 the DPSC considered a proposal to review the child resistant packaging of naphthalene (and camphor) following an increasing number of reports of poisoning in children. The committee agreed that domestic packs for naphthalene and camphor should be enclosed in child resistant packaging. The following phrase was added to Part 3 of the Poisons Standard:

A person must not sell or supply camphor or naphthalene in ball, block, disc, pellet or flake form for domestic use unless the balls, blocks, discs, pellets or flakes are enclosed in a device which prevents removal or ingestion of its contents.

May 1993, DPSC (#69)

In May 1993 the DPSC considered a proposal to introduce label exemptions for naphthalene (and camphor) and to amend the Schedule 5 entry for naphthalene. The committee recommended that Part 2 of the Poisons Standard be amended as follows:

The committee recommended that further review of the Schedule 5 entry for naphthalene to deferred to a future meeting pending advice on the toxicity of naphthalene.

November 1993, DPSC (#91)

At the November 1993 meeting of the DPSC, the committee supported a Drafting Advisory Panel (DAP) proposal, specifying permanent markings (normally placed on a label) on the actual device (used for camphor or naphthalene) in situations where the device, because of its design, could not accept normal labels. The device, which prevents removal of the contents when used correctly, permits the above household chemicals to be classified in Schedule 5 rather than Schedule 6, because of the reduced poisoning potential. The committee recommended the following addition to the Part 2 exemptions for naphthalene and camphor:

April 1994, National Drugs and Poisons Schedule Committee (NDPSC #1)

In April 1994, the NDPSC considered and agreed with a proposal to exempt devices containing camphor and naphthalene from some labelling requirements and requiring them to have the name of the poison and the word "WARNING" embossed on the device. The committee, taking into account the toxicity of camphor and naphthalene, also recommended the following:

• The current Appendix F entries for camphor and camphor blocks be combined whilst leaving the entry for camphor for external use to remain unchanged.
• The current Appendix F entry for naphthalene include the warning "Can be fatal to children if sucked or swallowed."
• In the Appendix E entry for naphthalene, the first aid statement "a" to be replaced by statement "i", because of the need to get to a hospital quickly, following ingestion of naphthalene.
• That because 100 mg of naphthalene can be lethal in children and because camphor is also toxic a change in schedule (to S6) be foreshadowed and gazetted for comment and consultation.

August 1994, NDPSC (#2)

At the August 1994 meeting of the NDPSC, the committee considered recommendations on naphthalene and camphor foreshadowed at the April 1994 meeting and subsequently gazetted for public consultation. In relation to naphthalene the committee reaffirmed its support for a Schedule 6 classification but sought further details of products marketed, other than naphthalene as such. It was considered that lower strengths or child resistant packaging would be grounds for lower scheduling classification. It was agreed that following receipt of the above information, the matter would be dealt with out of session.

It was noted that with the foreshadowed recommendation to move this poison from Schedule 5 to Schedule 6, it would be necessary to also exempt the devices from the packaging provisions of Sections 7 and 10.The committee recommended the following amendments to the Poisons Standard:

November 1994, NDPSC (#3)

At the November 1994 meeting of the NDPSC, the committee reaffirmed the Schedule 6 recommendation for naphthalene made at the August 1994 meeting on the basis of acute toxicity of naphthalene in humans (oral lethal dose in a child of 100 mg/kg), in the absence of comments arising from the gazettal of the proposal. The committee recommended the following amendment:

August 1995, NDPSC (#6)

At the August 1995 NDPSC, the Drafting Advisory Panel was requested to revise the proposed Schedule 6 entry for naphthalene as the proposal would automatically include its derivatives and preparations, whereas the original Schedule 5 entry specifically excluded these derivatives. The Committee agreed that the intention of the proposal for Schedule 6 was to include preparations but exclude derivatives and recommended the revised wording be adopted. The committee recommend that the Schedule 6 entry for naphthalene include the phrase 'excluding derivatives)'.

February 2001, NDPSC (#30)

At the February 2001 meeting of the NDPSC, the old standard statements i, b, and d for naphthalene were replaced with new standard statements A, G1 and G3.

October 2003, NDPSC (#39)

At the October 2003 meeting of the NDPSC, the committee considered a proposal to vary the label of an existing registered product containing naphthalene for use as a moth repellent in wardrobes, clothes drawers and for the protection of books and other paper or cloth based material in storage. The committee agreed to defer with matter to the February 2004 meeting.

February 2004, NDPSC (#40)

In February 2004 the NDPSC considered naphthalene, including several case reports of naphthalene poisoning via differing exposure routes (mostly from overseas) and confirmed that the Schedule 6 entry was appropriate and that a new warning statement should be included in Appendix F, Part 1. This warning statement (105) was identical to the wording of the FAISD statement 44. The NDPSC concluded that this statement should be a requirement for naphthalene products to alert users to the potential hazard that naphthalene presents to young children.

June 2006, NDPSC (#47)

In 2006 the NDPSC again considered naphthalene in light of an Australian report of haemolytic anaemia in a child exposed to naphthalene. In this case, flakes had apparently been used in the storage of furniture, including the baby's cot. The NDPSC reconfirmed that the Schedule 6 entry was appropriate and that warning statement 105 should remain a requirement for naphthalene products to alert users to the potential hazard that naphthalene presents to young children.

ACCS Members recalled that Appendix F (Warning Statements and Safety Directions) no longer applied to agricultural and veterinary chemicals registered by the APVMA i.e. this was set entirely through the APVMA's product approach process, with the FAISD providing guidance on labelling for this process.

June 2011 Advisory Committee on Chemicals Scheduling (ACCS #2)

In June 2011, the ACCS considered a proposal to amend the Poisons Standard with respect to naphthalene. The applicant proposed to increase the restrictions on domestic use of naphthalene through scheduling, including (but not necessarily limited to) mothballs, blocks, discs, pellets or flakes. The ACCS recommended that the term "flake" be included in Poisons Standard Part 2 Labels and Containers paragraphs 17, 28 and 29. In addition to this, the ACCS recommended that the term "flake" be included in the Appendix F, Part 3 entries for camphor and naphthalene. The ACCS also recommended that the existing Schedule 6 naphthalene entry be amended to exclude liquid hydrocarbons when present as impurities. The delegate agreed with the committee's advice and made a final decision with respect to naphthalene with an implementation date of 1 January 2012.

Australian regulations

Insecticide use of naphthalene is regulated by the Australian Pesticides and Veterinary Medicines Authority (APVMA), and products must comply with the APVMA's requirements, including labelling. There are nine (9) products containing naphthalene on the APVMA's PubCRIS.

Naphthalene is listed in Safe Work Australia's Hazardous Substances Information Systems (HSIS) as a Category 3 carcinogen with a risk phrase: "R40 Limited evidence of a carcinogenic effect and as harmful by the oral route".

International regulations

Reviews by the United States Environmental Protection Authority (US EPA) (2008), the Canadian Pest Management Regulatory Agency (PMRA) (2010) and the European Chemicals Bureau (2003) have not supported the use of loose or flaked forms of naphthalene.

European Union

Loose mothballs and flakes of naphthalene have not been available in the EU since mid-2009 when approval was withdrawn following a lack of commercial interest by manufacturers in funding new studies to support the chemical in a European review of biocide products.

Naphthalene is listed in Annex II/1167 "List of substances prohibited in cosmetic products' of the EU Regulation (EC) No 1223/2009.

Naphthalene is also considered a Class 2 Carcinogenic Substance.

United States of America (USA)

The US EPA does not permit the marketing of loose mothballs, thus requiring the containerisation of flakes and loose mothballs to reduce the risk of ingestion by children.

Canada

The PMRA has restricted naphthalene presentation to packaging that reduces the possibility for ingestion thus requiring the containerization of flakes and loose mothballs.

Naphthalene is in Schedule 5 and Schedule 7, Part 2 of the Export and Import of Hazardous Waste and Hazardous Recyclable Material Regulations SOR/2005-149.

Naphthalene is also listed in the Ingredient Disclosure List SOR/88-64 of the Hazardous Products Act and must be included in the list of ingredients when present at concentrations greater than 1% w/w.

Substance summary

Naphthalene is a polycyclic aromatic hydrocarbon and white crystalline powder with a characteristic odour. It is used as a starting material for a variety of industrial chemicals, dyes, resins, solvents, lubricants and fuel components. Naphthalene is also a moth repellent and insecticide.

Naphthalene slowly sublimes under ambient conditions; the vapour repels moths but can also be inhaled by house occupants (characteristic mothball smell).

Table 1: Chemical information for naphthalene

Property	Naphthalene
CAS name	N/A
CAS number	91-20-3
Chemical structure
Molecular formula	C10H8
Molecular weight	128.2 g/mol
IUPAC and/or common and/or other names	Bicyclo[4.4.0]deca-1,3,5,7,9-pentaene

Naphthalene is most commonly encountered by the public as mothballs or toilet deodorant blocks, but the compound is also generated from burning wood or tobacco and as a component of the essential oils of some medicinal and culinary herbs.

When used as a pest control product, naphthalene is an insecticide in the form of mothballs or flakes for control of moth and larvae which are destructive to textiles made of natural fibres. The products are placed in wardrobes, drawers, bedding stores, and similar areas where the naphthalene vapours can build up to levels toxic to the adult or larvae forms of the moth.

Cases of naphthalene poisoning in members of the public are regularly reported. The taste of naphthalene is not offensive to all people as children have been known to eat mothballs and toilet deodorant blocks, and case reports are available of pregnant women sucking on mothballs.

Metabolism

Following absorption into the liver, naphthalene is oxidised microsomal mixed-function oxidases to a range of metabolites, one or more of which are toxic. Following an initial 1, 2 epoxidation, naphthalene is converted to monohydric phenols such as 1- and 2-naphthols, dihydric phenols such as 1, 2- dihydroxynaphthalene and dihydrodiols such as dihydronaphthalene 1, 2-diol. These are mostly excreted as glucuronides or ethereal sulfates. Naphthalene 1,2-epoxide also reacts with reduced glutathione to form S-(2-hydroxy-l,2-dihydroxynaphthyl) glutathione. This in turn is converted to S- (hydroxy-l,2 dihydronaphthyl) acetyl-L-cystenine, which is excreted as I-naphthylmercapturic acid.

Toxicity

Ingestion or inhalation of naphthalene can lead to haemolytic anaemia which can be fatal. Inhalation, rat: LC50 = >340 mg/m³/1H;

Oral, rat: LD50 = 490 mg/kg²

Pharmacology

Individuals with glucose-6-phosphate (G6P) deficiency are at increased risk when exposed to naphthalene.

G6P deficiency is reportedly present in about five per cent of Australians, mainly those of Asian, African, Middle Eastern or Mediterranean descent. This enzyme deficiency makes affected individuals liable to red cell haemolysis following naphthalene exposure. Haemolysis, whether due to chemical exposure or underlying pathological processes, leads to the production of bilirubin (as a breakdown product of haemoglobin from the lysed red cells) which causes jaundice. In adults and older children, jaundice is relatively harmless in itself. However, if this process occurs in the fetus or infant when the blood brain barrier is not fully formed, some of this bilirubin enters the brain and is deposited in cell bodies (grey matter), especially the basal ganglia, causing irreversible damage. Depending on the level of exposure, the effects range from clinically unnoticeable to severe brain damage and even death. In severe cases of haemolysis there can also be serious kidney and liver damage resulting from precipitated haemoglobin.

Human carcinogenicity

The International Agency for Research on Cancer^[18] concluded that "there is inadequate evidence in humans for the carcinogenicity of naphthalene. There is sufficient evidence in experimental animals for the carcinogenicity of naphthalene.

The overall evaluation is that naphthalene is possibly carcinogenic to humans (Group 2B). Whilst the evidence for carcinogenicity in rodents is convincing, the relevance to humans at likely domestic exposure levels is questionable as the available evidence points to a considerably lower susceptibility of humans than of rodents.

Tumours in rodents occurred in tissues especially prone to naphthalene injury (hyperplasia, inflammation and/or necrosis) when exposure was by either the inhalation or the intraperitoneal route.

Pre-meeting public submissions

Four public submissions were received before the first closing date in response to an invitation published on 31 August 2018 under regulation 42ZCZK of the Regulations; one in support of the proposal and three opposed.

The main points provided in opposition of the amendment were:

• Naphthalene toxicity is well established and severe toxicity can occur from relatively small oral or inhaled exposures. Those in the population with G6PD deficiency are at particular risk, and are usually not aware of this increased individual risk.
• The NSW Poisons Information Centre receives calls regarding exposures to naphthalene (92 calls since 2014, 32 requiring hospitalisation) as well as exposures to moth balls of an unknown content, potentially containing naphthalene (113 calls since 2014, 16 requiring hospitalisation). Many of these phone calls involve loose moth balls or parts of moth balls which had escaped the caged packaging designed to prevent exposures.
• With the ready availability of safer alternatives, the risk benefit analysis of naphthalene now favours a change to Schedule 7.

The main points provided in support of the amendment were:

• The proposal to limit public exposure of naphthalene only addresses the safety of mothballs in the domestic setting. Naphthalene is much more predominantly used in Australia, in industrial products and processes i.e. as a solvent, in dyes, heat transfer fluid, additives, coatings, textiles, binders, adhesives and surfactants. It is also an impurity in liquid hydrocarbons such as diesel (hence the current exemption).
• Naphthalene is found in naphtha and distillate fractions and can be present in reasonable quantities in aromatic solvents. With the proposed scheduling amendment, a number of automotive and agricultural products would become Schedule 7 Poisons.
• Adding all forms and uses of naphthalene to Schedule 7 as proposed would present significant issues for industry. It would mean that industrial products consisting of and/or containing naphthalene (other than liquid hydrocarbons where it is present as an impurity) would be inadvertently captured and required to comply with the Schedule 7 requirements, including licensing. It would become extremely difficult, if not impossible to continue marketing these products. This seems a disproportionate effect given that no public health concerns have been raised with these industrial uses of naphthalene and naphthalene containing products.
• There is lack of clarity as to whether or not naphthalene occurring naturally in petroleum crude oil would or would not be considered to be an impurity. Previous requests for clarification from the Scheduling Secretariat have produced advice that 'this would constitute a legal opinion and cannot be given.' With the Appendix G exclusion concentration of 1 mg per litre or kilogram it could cause undue concern and hardship to Industry.
• The current Schedule 6 exception on hydrocarbon liquids for naphthalene could be improved as the term 'impurity' causes confusion with the general cut-off limits (10 mg/kg) allocated for S6.
• Suggested changes to the proposed S7 entry (if warranted) and (two alternative) changes to S6;

  Schedule 6 NAPHTHALENE (excluding its derivatives) except:

  1. when present at less than 0.5% naphthalene in liquid hydrocarbons.
  2. when included in Schedule 7; or
  3. when in liquid hydrocarbons as an impurity; or
  4. when included in Schedule 7

  Schedule 7 - New Entry

  NAPHTHALENE in mothball use

Joint ACMS-ACCS advice

The committee recommended that a new schedule 10 Poisons Standard entry be created for naphthalene as follows:

In addition, the committee recommended an implementation date of 1 June 2019, since non-compliant products pose a serious risk to the public, and this is the earliest date possible.

Members agreed that the relevant matters under Section 52E(1) of the Therapeutic Goods Act 1989 included: (a) the risks and benefits of the use of a substance; (b) the purposes for which a substance is to be used and the extent of use of a substance; (c) the toxicity of a substance; (d) the dosage, formulation, labelling, packaging and presentation of a substance; (e) the potential for abuse of a substance; and (f) any other matters that the Secretary considers necessary to protect public health.

The reasons for the advice included:

1. the risks and benefits of the use of a substance:
   • The benefit of use of naphthalene rather than camphor mothballs is not clear, and there is increased risk. However, the risk is significantly mitigated if proper containment is used.
   • Known risk of toxicity in domestic environment due to inhalation and ingestion, notably in children.
   • Continued reports of toxicity indicate current scheduling, labelling and packaging restrictions may be ineffective.
   • Known benefits in industrial products and processes.
2. the purposes for which a substance is to be used and the extent of use of a substance:
   • Domestic use as moth repellent; safer alternatives available.
   • 5/9 of the APVMA registered products are moth ball products for home use, the others are insecticides.
   • Predominant use in industrial products and processes.
3. the toxicity of a substance:
   • Toxicity appears to meet the SPF for Schedule 6. However:
     • Dangerous poison; ingestion or inhalation can lead to haemolytic anaemia which can be fatal.
     • 100 mg can be fatal in a child; as little as one mothball (can contain 0.5-5 g naphthalene) can result in toxicity in children.
     • EPA has classified naphthalene as a Group C, possible human carcinogen.
4. the dosage, formulation, labelling, packaging and presentation of a substance:
   • Approved products are contained and therefore reduce risk. Loose naphthalene balls and flake for domestic use are not legal products, but may be singled out for special scheduling controls.
   • Packaging requirements - naphthalene in ball, block, disc, pellet or flake form for domestic use must be enclosed in a device which prevents removal or ingestion of its contents, is incapable of reacting with the poison, is sufficiently strong, has the word "POISON" and the name of the poison embossed or indelibly printed on it.
   • Evidence these requirements are not being complied with in all cases, availability in some retail outlets and online in loose form.
5. the potential for abuse of a substance:
   • Some reports of abuse via deliberate inhalation of mothballs.

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