Warfarin |
![]() Last updated: 18/08/2025 |
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(Also known as: coumafene; coumaphene; zoocoumarin; warfarine) |
SUMMARY |
Hazard alerts |
The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement. These hazard alerts do not take account of usage patterns or exposure, thus do not represent risk.
Environmental fate | Ecotoxicity | Human health |
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A rarely used anticoagulant rodenticide | |
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Rats; Mice; Grey squirrels; Gophers | |
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Rats; Mice; Grey squirrels; Gophers | |
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GB regulatory status |
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Not approved | ||
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Expired | ||
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No UK approval for use as a plant protection agent |
EC Regulation 1107/2009 (repealing 91/414) |
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Not approved | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Ireland | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Expired | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Not applicable | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Yes | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Additional information |
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Chemical structure |
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Warfarin is a chiral compound comprising an equal mixture of (R) and (S) enantiomers. (S)-Warfarin is considerably more potent and pharmacologically active than (R)-Warfarin. | |
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C₁₉H₁₆O₄ | |
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CC(=O)CC(C1=CC=CC=C1)C2=C(C3=CC=CC=C3OC2=O)O | |
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PJVWKTKQMONHTI-UHFFFAOYSA-N | |
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InChI=1S/C19H16O4/c1-12(20)11-15(13-7-3-2-4-8-13)17-18(21)14-9-5-6-10-16(14)23-19(17)22/h2-10,15,21H,11H2,1H3 | |
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Yes |
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Common Name | Relationship | Link |
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warfarin | Unstated isomer | ![]() |
sodium warfarin | Variant | ![]() |
General status |
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Rodenticide | |
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Coumarin rodenticide | |
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990 g kg⁻¹ | |
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EU dossier - None declared | |
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Synthetic | |
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1st generation anticoagulant | |
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81-81-2 | |
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201-377-6 | |
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70 | |
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086002 | |
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54678486 | |
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607-056-00-0 | |
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308.33 | |
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rac-4-hydroxy-3-[(1R)-3-oxo-1-phenylbutyl]-2H-1-benzopyran-2-one | |
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4-hydroxy-3-[(1RS)-3-oxo-1-phenylbutyl]coumarin | |
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4-hydroxy-3-(3-oxo-1-phenylbutyl)-2H-1-benzopyran-2-one | |
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Marine Pollutant; Chemical subject to PIC regulations | |
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Not applicable | |
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Not applicable | |
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Not applicable | |
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Not applicable | |
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Colourless to white crystalline powder | |
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Commercial |
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Current | |||
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circa 1944, introduced | |||
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Often supplied as ready-to-use baits, granules or bait concentrate | |||
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Warfarin is commercially produced through a multi-step organic synthesis that begins with two key starting materials: 4-hydroxycoumarin and benzylideneacetone. The first major reaction is an aldol condensation, where these compounds react in the presence of a base like sodium hydroxide to form an intermediate known as 3-(alpha-acetonylbenzyl)-4-hydroxycoumarin. This intermediate then undergoes a cyclisation reaction under acidic conditions, typically using hydrochloric acid, to form the core structure of warfarin. The crude product is usually impure and requires purification, often achieved through recrystallisation, where the compound is dissolved in a solvent and slowly crystallised to remove impurities. | |||
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There is no publicly available life cycle assessment (LCA) that provides a precise GHG emission figure specifically for the production of warfarin. However, insights from broader pharmaceutical sector analyses suggest that drug manufacturing is highly energy-intensive and contributes significantly to GHG emissions. While exact numbers vary, producing 1 kilogram of a typical small-molecule pharmaceutical like warfarin could generate between 5 to 25 kilograms of CO₂-equivalent emissions, depending on synthesis complexity, energy sources, and purification requirements. |
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267 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
Moderate | ||||||||
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54600 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Acetone5 = Verified data used for regulatory purposes |
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6.4 | A4 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) n-Heptane4 = Verified data |
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22200 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Methanol5 = Verified data used for regulatory purposes |
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16900 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Ethyl acetate5 = Verified data used for regulatory purposes |
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165 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
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5.01 X 1000 | Calculated | - | |||||||
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0.7 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
Low | ||||||||
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1.35 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
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5.19 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
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Weak acid | |||||||||||
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3.0 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
Low volatility. If applied directly to plants or soil, drift is a concern & mitigation is advisable | ||||||||
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3.50 X 10-03 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
Non-volatile | ||||||||
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Neutral solution: Maxima at 272, 282.5 & 306nm Basic solution: Maxima at 212.5, 293.5 and 311nm |
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
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Degradation |
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5 | K4 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here ) 4 = Verified data |
Non-persistent | |||||||
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5 | K4 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here ) 4 = Verified data |
Non-persistent | ||||||||
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Stable | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
Stable | |||||||
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Not a significant degradation route | ||||||||||
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Stable | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
Stable | |||||||
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Stable pH 5 to pH 9 | ||||||||||
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As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below. | ||||||||||
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Soil adsorption and mobility |
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14.15 | A4 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 4 = Verified data |
Moderately mobile | |||||||
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EU dossier Kf range 0.66-46.77 mL g⁻¹, Kfoc range 18-390 mL g⁻¹ | ||||||||||
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Adsorption increases with decreasing soil pH |
Fate indices |
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1.23 | Calculated | Low leachability | ||||||||||||||||||||||||||
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3.99 X 10-03 | Calculated | - | |||||||||||||||||||||||||
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Low | Calculated | - | ||||||||||||||||||||||||||
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Moderately mobile | Calculated | - | ||||||||||||||||||||||||||
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2.4 | A4 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Calculated using the Atkinson method4 = Verified data |
Below the level of concern for long-range air transport | ||||||||||||||||||||||||||
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Low risk | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Based on LogP < 35 = Verified data used for regulatory purposes |
Low risk | |||||||||||||||||||||||||
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Known soil metabolites |
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- | - | Aerobic | |||||
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- | - | Aerobic |
Known groundwater metabolites |
None
Other known metabolites |
None
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Terrestrial ecotoxicology |
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10.4 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Rat5 = Verified data used for regulatory purposes |
High | ||||||||
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> 2000 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Colinus virginianus5 = Verified data used for regulatory purposes |
Low | ||||||||
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4448 mg kg feed⁻¹ | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Colinus virginianus5 = Verified data used for regulatory purposes |
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> 10 | E3 E = Manufacturers safety data sheets Eisenia foetida3 = Unverified data of known source |
Moderate | ||||||||
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> 100 | E3 E = Manufacturers safety data sheets Non-toxic when used as rodent bait3 = Unverified data of known source |
Low | ||||||||
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Aquatic ecotoxicology |
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65.0 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Oncorhynchus mykiss5 = Verified data used for regulatory purposes |
Moderate | ||||||||
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2.0 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Oncorhynchus mykiss5 = Verified data used for regulatory purposes |
Moderate | ||||||||
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304.6 | F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment ) Danio rerio Embryo3 = Unverified data of known source |
Low | ||||||||
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> 105 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Daphnia magna5 = Verified data used for regulatory purposes |
Low | ||||||||
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> 8.5 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Raphidocelis subcapitata5 = Verified data used for regulatory purposes |
Moderate | ||||||||
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8.5 | Q2 Q = Miscellaneous data from online sources Unknown species2 = Unverified data of unknown source |
Low | ||||||||
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General |
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High (class III) | - | - | ||||||||
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10.4 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Rat5 = Verified data used for regulatory purposes |
High | ||||||||
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40 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Rat5 = Verified data used for regulatory purposes |
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> 0.005 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Rat 4 hr5 = Verified data used for regulatory purposes |
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None allocated | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
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None allocated | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
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0.0002 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Human therapeutic dose SF=1005 = Verified data used for regulatory purposes |
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Risk of exposure consider very low due to usage pattern | |||||||||
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May be absorbed through the skin | ||||||||||
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Health issues |
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Highly toxic Anticoagulant - causes internal hemorrhage May be absorbed through the skin and cause systemic poisoning |
Handling issues |
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Not explosive IMDG Transport Hazard Class 6.1 Not expected to auto-ignite; Not highly flammable |
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Health: H300, H310, H330, H372, H360D Environment: H411 |
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Ib (Highly hazardous) | |||
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UN3077 | |||
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Packaging Group I (great danger) | |||
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warfarin | ||
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warfarin | ||
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Warfarin | ||
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warfarin | ||
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warfarin | ||
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warfarina | ||
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warfarin | ||
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warfarin | ||
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warfarine | ||
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Record last updated: | 18/08/2025 |
Contact: | aeru@herts.ac.uk |
Please cite as: | Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242 |