2.5 Interim decision in relation to lambda-cyhalothrin

2. Interim decisions on proposed amendments referred to the Advisory Committee on Chemicals Scheduling (ACCS #26, November 2019)

2.5. Interim decision in relation to lambda-cyhalothrin

Interim decision

Pursuant to regulation 42ZCZN of the Regulations, a Delegate of the Secretary has, in relation to the proposed amendment, made an interim decision to amend the current Poisons Standard in relation to lambda-cyhalothrin as follows:

Proposed date of effect of the proposed amendment

1 June 2020

Reasons for the interim decision (including findings on material questions of fact)

In this section: Applicant's scheduling proposal and reasons for the proposal | Current scheduling status | Scheduling history | Australian regulations | International regulations | Summary of pre-meeting public submissions | Summary of ACCS advice/recommendations to the Delegate | Delegate's considerations | Reasons for interim decision

Applicant's scheduling proposal and reasons for the proposal

An application to amend the current Poisons Standard with respect to lambda-cyhalothrin was considered. The application proposed to amend the Schedule 5 cut-off for aqueous preparations containing microencapsulated lambda-cyhalothrin.

The Applicant's proposed amendments to the Poisons Standard were:

The Applicant's main points provided in support of the proposed amendment were as follows:

• Based on the product acute toxicity, and providing that adequate warnings and safety directions recommended in the present report are displayed on the product label, the product formulation containing lambda-cyhalothrin meets the Scheduling Policy Framework (2018) criteria for Schedule 5 of the Standard for Uniform Scheduling of Medicines and Poisons (SUSMP). There are no other concerns in relation to the potential health hazard when used according to the proposed draft label. The product is presented in a similar manner to a range of other commonly available insecticidal sprays. No specialised equipment is required for safe use.

Current scheduling status

Lambda-cyhalothrin is currently listed in the Poisons Standard as follows:

Scheduling history

In November 1987, the Drugs and Poisons Schedule Committee (DPSC) decided to include first aid and safety directions for lambda-cyhalothrin.

In August 1990, the DPSC decided to include preparations containing 1 per cent or less of lambda-cyhalothrin in Schedule 6 and all other preparations containing lambda-cyhalothrin in Schedule 7, based on the toxicity profile of lambda-cyhalothrin. Toxicity data discussed at this meeting included an oral dosing study in dogs, which revealed be short-lived and non-cumulative dose related neurotoxic effects. In addition, a study in human volunteers devoid of asthma revealed that aerosols of lambda-cyhalothrin elicited some mild reaction in more than 50 per cent of volunteers. A dose response relationship was established for the incidences of smarting and watering of the eyes, sneezing, blocked or runny noses and throat/lung irritation.

In November 1991, the DPSC decided to include aqueous preparations containing 1 per cent or less of lambda-cyhalothrin in Schedule 5. The reason for this decision was that the water-based product containing 1 per cent or less of lambda-cyhalothrin provided it was confined to use by pest control operators through a registration mechanism. The minutes' state that the oral LD50 for the product in rats was >2000 mg/kg.

In November 1994, the NDPSC considered toxicological data on a microencapsulated aqueous suspensions containing 10 per cent lambda-cyhalothrin. Members noted that technical lambda-cyhalothrin had been demonstrated to have slight skin and eye irritancy and may cause transitory facial numbness in humans. The Committee recommended that because of the potential for moderate skin irritation and temporary facial numbness, and the restriction of its use to professional pest operators that microencapsulated aqueous suspensions containing 2.5 per cent or less of lambda-cyhalothrin be included in Schedule 5.

In August 1999, the NDPSC decided to include microencapsulated preparations containing 25 per cent or less of lambda-cyhalothrin in Schedule 6.

In August 2014, the chemicals scheduling delegate decided to increase the allowed concentration in Schedule 6 from 1.5 to 1.6 per cent to ensure that the product formulation, when expressed in grams per 100 millilitre (as per Part I of the Poisons Standard), is covered by the amended entry.

In October 2017, the chemicals scheduling delegate decided to amend the Schedule 6 entry for lambda-cyhalothrin to include emulsifiable granule formulations containing 25 per cent or less of lambda-cyhalothrin.

In June 2019, the Advisory Committee on Chemicals Scheduling considered a proposal to amend the Schedule 5 entry for lambda-cyhalothrin, to allow up to four per cent or less in aqueous microencapsulated preparations. The 'up and down' method for deriving the acute oral LD₅₀ toxicity data was considered to be imprecise and the committee recommended that this was insufficient to justify a Schedule 5 entry. The chemicals scheduling delegate made an interim decision not to amend the Schedule 5 entry.

Australian regulations

• Lambda-cyhalothrin is not listed on the TGA Ingredient Database.
• There are no medicines currently active on the Australian Register of Therapeutic Goods (ARTG)^[194] that contain lambda-cyhalothrin as an active ingredient.
• Lambda-cyhalothrin is not listed in the Therapeutic Goods (Permissible Ingredients) Determination No. 4 of 2019,^[195] and is not an excipient or active in any products on the ARTG.
• The Database of Adverse Event Notifications (DAEN)^[196] contains no reports of adverse events for products containing lambda-cyhalothrin as an active ingredient.
• As of 31 July 2019, there are 52 products containing Lambda-cyhalothrin listed on the Public Chemical Registration Information System Search (PubCRIS).^[197] Of these, 14 are active constituent listings and 39 are end-use products.
• There is one adverse report relating to lambda-cyhalothrin in the APVMA's Adverse Experience Reporting Program annual reports^[198] from 1995-2015. The report cited in 2015 included 1 case of malaise, allergy and respiratory problems.

International regulations

USA

Lambda-cyhalothrin was registered with the US Environmental Protection Agency (US EPA) in 1989 and is registered as a biochemical/conventional chemical. It is a restricted use, broad spectrum insecticide used to control most major aphid, caterpillar and beetle pests on a wide variety of crops and for public health pests such as mosquitoes and cockroaches in non-agricultural settings.

Canada

Lambda-cyhalothrin is a registered pesticide with Health Canada. There are 22 registered products in Canada containing lambda-cyhalothrin.

Canada re-evaluated Decision PRVD2017-03 of lambda-cyhalothrin in June 2017. The page states 'Before making a final re-evaluation decision on lambda-cyhalothrin, the PMRA will consider all comments received from the public in response to PRVD2017-03, Lambda-cyhalothrin. The PMRA will then publish a Re-evaluation Decision that will include the decision, the reasons for it, a summary of comments received on the proposed decision and the PMRA's response to these comments'. However, it does not appear that Health Canada have published the Re-evaluation Decision.

UK

Lambda-cyhalothrin was first approved for use in the UK in 1988 (Advisory Committee on Pesticides, 1988).

EU

Lambda-cyhalothrin is currently a registered active ingredient with the European Chemicals Agency (ECHA). The ECHA hazard classification for lambda-cyhalothrin is 'Danger! According to the classification provided by companies to ECHA in CLP notifications this substance is fatal if inhaled, is very toxic to aquatic life with long lasting effects, is toxic if swallowed, is toxic in contact with skin and is very toxic to aquatic life.'

Lambda-cyhalothrin is listed in Annex III - substances predicted as likely to meet criteria for category 1A or 1B carcinogenicity, mutagenicity, or reproductive toxicity.

New Zealand (NZ)

Lambda-cyhalothrin is currently an approved chemical with the NZ EPA.

Summary of pre-meeting public submissions

No submissions were received response to the notice published under regulation 42ZCZK advising of the proposed amendment.

Summary of ACCS advice/recommendations to the Delegate

The Committee recommended amending the Schedule 5 entry for lambda-cyhalothrin in the Poisons Standard as follows:

The Committee also recommended an implementation date of 1 June 2020.

Members agreed that the relevant matters under Section 52E(1) of the Therapeutic Goods Act 1989 included (a) risks and benefits of the use of a substance; (b) the purpose for which a substance is to be used and the and extent of use; (c) the toxicity of a substance; and (d) the dosage, formulation, labelling, packaging and presentation of a substance.

The reasons for the advice included:

52E(1) Considerations	Reasons
a - the risks and benefits of the use of a substance	The risks relating to lambda-cyhalothrin are mitigated by formulation. However, it is essentially a low toxicity presentation as the microencapsulation of lambda-cyhalothrin is consistent with the Schedule 5 Scheduling Factors.
b - the purposes for which a substance is to be used and the extent of use of a substance	Lambda-cyhalothrin is an insecticide intended for professional use in commercial, industrial, public and domestic premises.
c - the toxicity of a substance	Lambda-cyhalothrin has low oral and dermal toxicity.
d - the dosage, formulation, labelling, packaging and presentation of a substance	Aqueous preparation of microencapsulated lambda-cyhalothrin is to be supplied as a concentrate in containers from 250 mL (bottle) or 50 ml (sachet). Lower package size may be used by a householder.
e - the potential for abuse of a substance	Nil.
f - any other matters that the Secretary considers necessary to protect public health	Nil

Delegate's considerations

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

• The application to amend the current Poisons Standard with respect to lambda-cyhalothrin;
• Advisory Committee on Chemicals Scheduling's advice;
• 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; and (d) the dosage, formulation, labelling, packaging and presentation of a substance.
• The Australian Health Ministers' Advisory Council's Scheduling Policy Framework (SPF 2018); and
• Scheduling Handbook (V 1.1, July 2019).

Reasons for interim decision

I agree with the Committee's finding that the relevant provisions of section 52E of the Therapeutic Goods Act 1989 are: (a) the risks and benefits of the use of a substance; (b) the purpose for which a substance is to be used and the and extent of use of a substance; (c) the toxicity of a substance; and (d) the dosage, formulation, labelling, packaging and presentation of a substance.

In my view, the relevant parts of the SPF 2018 are the Scheduling Factors for Schedules 5.

• I have taken into consideration the toxicological data on lambda-cyhalothrin provided by the Applicant and have made the decision to increase the increase the cut-off to Schedule 5 from 2.5 per cent to 10 per cent. I am satisfied that on balance, the benefits outweigh any potential public health risks. In making my decision, I have considered the Scheduling Factors for inclusion in Schedule 5. Microencapsulated lambda-cyhalothrin is an insecticide intended for professional use in commercial, industrial, public and domestic premises and has no established therapeutic value in humans. The acute toxicity data for microencapsulated lambda-cyhalothrin are consistent with the SPF Schedule 5 Scheduling Factors, including being a slight eye irritant. However, it is neither a skin irritant nor a skin sensitiser. In considering the toxicity data provided for a formulation containing 10 per cent microencapsulated lambda-cyhalothrin, I am satisfied that it supports a presentation of a low hazard from repeated use and is unlikely to produce irreversible toxicity.
• I have considered the advice from the APVMA regarding the lack of a risk assessment on neurotoxicity and agree with the Committee's recommendation that observed neurotoxic effects are transient and are expected to be equivalent to or no greater than that of the currently registered product which uses similar application rates. Furthermore, no other significant toxicities have been identified (e.g. respiratory sensitisation, mutagenicity, carcinogenicity, reproductive toxicity etc.) supporting that microencapsulated lambda-cyhalothrin at a concentration of 10 per cent or less presents a low potential for causing harm.

While there is a possibility that the smaller pack sizes may be sold to non-professionals for use in domestic settings, the risks associated with it being used contrary to the APVMA-approved directions are no greater than non-compliant professional use. Given that there is no legal mechanism to prevent sale of the smaller pack sizes into the home garden (domestic) market as it relates to the Poison Standard, I have given little weight to the potential availability to domestic users via hardware retailers and/or garden centres in making my decision.

• Taking into consideration that lambda-cyhalothrin is present in a number of registered agricultural products, the proposed use is similar to other commonly available insecticides and its toxicity profile has been well established, I am satisfied that the weight of evidence supports the increase to the Schedule 5 cut-off to 10 per cent. Further, the proposed APVMA labelling (including First Aid Instructions and Safety Direction) will mitigate any potential health risks associated with the use of the product.

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