Second generation anti-coagulant rodenticides—priority 2

Chemical class Anticoagulant rodenticides—group includes brodifacoum, bromadiolone, difenacoum, difethialone, and flocoumafen
Chemical Structure  
CAS Number Brodifacoum (56073-10-0), Bromadiolone (28772-56-7), Difenacoum (56073-07-5), Difethialone (104653-34-1), Flocoumafen (90035-08-8)
Mode of action Anticoagulant
Target pests Rodents
Hosts Agricultural, industrial and domestic premises
Formulations Bait, liquid concentrate, pellet, sachet, bait concentrate, block (inc stick) and wax block
Home garden use Yes
No of Australian Approvals and Registrations

Brodifacoum—10 active constituents, 60 products

Bromadiolone—8 active constituents, 25 products

Difenacoum—3 active constituents, 37 products

Difethialone—1 active constituent, 10 products

Flocoumafen—3 active constituents, 4 products

Poison schedule

Brodifacoum—Appendix J, Part 2.

Schedule 6

Brodifacoum in preparations containing 0.25 per cent or less of brodifacoum.

Schedule 7

Brodifacoum except when included in Schedule 6.

Bromadiolone—Schedule 6

Bromadiolone in preparations containing 0.25 per cent or less of bromadiolone.

Schedule 7

Bromadiolone except when included in Schedule 6.

Difenacoum—Appendix J, Part 2.

Schedule 6

Difenacoum in preparations containing 0.25 per cent or less of Difenacoum.

Schedule 7

Difenacoum except when included in Schedule 6.

Difethialone—Schedule 6

Difethialone in rodent baits containing 0.0025 per cent or less of difethialone.

Schedule 7

Difethialone except when included in Schedule 6.

Diphacinone—Schedule 6.

Flocoumafen—Schedule 6

Flocoumafen in preparations containing 0.005 per cent or less of flocoumafen.

Schedule 7

Flocoumafen except when included in Schedule 6.

Australian Health-based guidance values

Brodifacoum: ADI—0.0000005 mg/kg bw per day (1990)

Bromadiolone: ADI—0.000002 mg/kg bw per day (1994)

Difenacoum: No Australian ADI established

Difethialone: ADI—0.0000006 mg/kg bw per day (1993)

Flocoumafen: ADI—0.000001 mg/kg bw per day (1995)

Brodifacoum, bromadiolone, difenacoum and flocoumafen: No Australian ARfD established

Difethialone: ARfD—0.0005 mg/kg bw (2007)

Key issues

  • These chemicals persist in organs of poisoned rodents and present a risk to non-target animals that feed on poisoned animals or carcasses.
  • Use of products in domestic premises, animal production facilities and food production facilities is currently allowed. This presents potential risks to humans, pets and wildlife through accidental poisoning. Around 1400 human exposure incidents to rodent baits are reported to Poisons Information Centres annually.
  • Products are not intended for use in crops or the field, though some labels make it difficult to discern this.
  • Use of liquid formulations is a concern because they are not designed for use in bait stations. 

Stakeholder perspective

  • If the second generation anti-coagulant rodenticides were to be removed then less effective anti-coagulants are available.

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