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Piperonyl butoxide (Ref: ENT 14250)
Last updated: 03/08/2025
(Also known as: PBO; butacide; butoxide)

GENERAL INFORMATION
Description
An unclassified synergist used in a wide variety of insecticides to provide enhanced performance of the active ingredient
Examples of veterinary uses
Typically used in products for lice, flea and fliy infestations
Examples of species treated
Cats; Dogs; Horses; Pigeons; Caged birds
Approval status
VMR 2013/2033 approval status (GB/UK)
Approved
EU Regulatory approval status
Approved
Chemical structure
Isomerism
None
Chemical formula
C₁₉H₃₀O₅
Canonical SMILES
CCCCOCCOCCOCC1=CC2=C(C=C1CCC)OCO2
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
FIPWRIJSWJWJAI-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C19H30O5/c1-3-5-7-20-8-9-21-10-11-22-14-17-13-19-18(23-15-24-19)12-16(17)6-4-2/h12-13H,3-11,14-15H2,1-2H3
2D structure diagram/image available?
Yes
General status
Veterinary substance type
Product performance enhancer
Other bioactivity & uses
Synergist
Substance groups
Cyclic aromatic substance; Synergist
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Blocks pests natural detoxification system. Synergist. P450-dependent monooxygenase inhibitor.
Molecular targets
[Cytochrome P-450, Inhibitor]
CAS RN
51-03-6
EC number
200-076-7
CIPAC number
33
US EPA chemical code
067501
PubChem CID
-
Therapeutic Class
Sensory organs: Otological substances
ATCvet Code
QS02QA
Controlled Drug?
No
Regulation 37/2010 MRL Classification
Allowed substance (Table 1: Bovine, Ovine, Caprine, Equidae)
Molecular mass
338.44
PIN (Preferred Identification Name)
-
IUPAC name
5-[2-(2-butoxyethoxy)ethoxymethyl]-6-propyl-1,3-benzodioxole
CAS name
5-((2-(2-butoxyethoxy)ethoxy)methyl)-6-propyl-1,3-benzodioxole
Forever chemical
-
Other status information
Listed on USA Toxic Release Inventory; Some applications may be approved under GB Biocides Products Regulations
Relevant Environmental Water Quality Standards
-
Physical state
Colourless to yellow oily liquid
Related substances & organisms
Commercial
Property
Product
Manufacturer
Authorisation Route
Legal Class (GB/UK)
Availability status
Current
Introduction & key dates
circa 1950, introduced
Example products (past and present) using this active
Beaphar Cat Flea Spray Sinclair Animal & Household Care Ltd UK National authorisation Authorised veterinary medicine for general sale (AVM-GSL)
Beaphar Ear Drops Solution Sinclair Animal & Household Care Ltd UK National authorisation Authorised veterinary medicine for general sale (AVM-GSL)
Johnson's Anti Pest Insect Spray Johnsons Veterinary Products Ltd UK National authorisation Authorised veterinary medicine for general sale (AVM-GSL)
Pets with Wilko Insectidal Shampoo Sinclair Animal and Household Care Ltd UK National authorisation Authorised veterinary medicine for general sale (AVM-GSL)
Formulation and application details
Formulated for topical application such as cutaneous sprays, shampoos and powders
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
14.3
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Moderate
Solubility - In organic solvents at 20 °C (mg l⁻¹)
- - -
Melting point (°C)
Not applicable
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Boiling point (°C)
- - -
Degradation point (°C)
164
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
-
Flashpoint (°C)
179
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
-
Octanol-water partition coefficient at pH 7, 20 °C
P
5.62 X 1004 Calculated -
Log P
4.75
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
High
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.06
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Dissociation constant pKa) at 25 °C
- - -
-
Vapour pressure at 20 °C (mPa)
2.00 X 10-02
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
2.30 X 10-06
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Non-volatile
Volatilisation as max % of applied dose lost
From plant surface
- - -
From soil surface
- - -
Maximum UV-vis absorption L mol⁻¹ cm⁻¹
- - -
Surface tension (mN m⁻¹)
50.39
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
-
Refractive Index
1.497-1.507
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
-
Environmental release
-
Degradation
Property
Value
Source; quality score; and other information
Interpretation
Soil degradation (days) (aerobic)
DT₅₀ (typical)
13
K4 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here )
4 = Verified data
Non-persistent
DT₅₀ (lab at 20 °C)
- - -
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
Note
Best available data
Manure DT₅₀ (days)
- - -
Aqueous photolysis DT₅₀ (days) at pH 7
Value
- - -
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
250
H3 H = The US ARS pesticide properties database. Dataset is no longer available.
3 = Unverified data of known source
Persistent
Note
Stable pH 5 to pH 9 at 25 °C
Water-sediment DT₅₀ (days)
- - -
Water phase only DT₅₀ (days)
- - -
Sediment phase only DT₅₀ (days)
- - -
Air degradation
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.
Decay in stored produce DT₅₀
-
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd (mL g⁻¹)
-
W3 W = French database provided by ARVALIS-Institut du Végétal. Dataset no longer available.
3 = Unverified data of known source
Non-mobile
Koc (mL g⁻¹)
89125
Notes and range
Other data: Koc range 399-830 mL g⁻¹ (L3)
Freundlich
Kf (mL g⁻¹)
- - -
Kfoc (mL g⁻¹)
-
1/n
-
Notes and range
-
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
-1.06 Calculated Low leachability
Bio-concentration factor
BCF (l kg⁻¹)
260
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
Lepomis macrochinis
Threshold for concern
CT₅₀ (days)
Not available -
Known metabolites

None

ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 7220
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Low
Mammals - Short term dietary NOEL
(mg kg⁻¹)
30
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Rat 2 yr
High
(ppm diet)
- -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
> 2250
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Colinus virginianus
Low
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
- - -
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
- - -
Soil micro-organisms
- - -
Collembola
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
Non-target plants
Vegetative vigour ER₅₀ (g ha⁻¹)
- - -
Seedling emergence ER₅₀ (g ha⁻¹)
- - -
Honeybees (Apis spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
294
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
Apis mellifera
Low
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Chronic
- - -
Notes
[The residual time to 25% mortality (RT25) value for honeybees is 3 hrs - USEPA data]
Bumblebees (Bombus spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
-
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
-
Mason bees (Osmia spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Other bee species (1)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Other bee species (2)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Beneficial insects (Ladybirds) as Mortality LC₅₀ mg l⁻¹
> 1644
F4 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 )
4 = Verified data
Coccinella septempunctata Adult
-
Beneficial insects (Lacewings) as Mortality, Contact LD₅₀ g l⁻¹
> 1.71
F4 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 )
4 = Verified data
Chrysoperla carnea Larva
Moderate
Beneficial insects (Parasitic wasps)
- - -
Beneficial insects (Predatory mites)
- - -
Beneficial insects (Ground beetles)
- - -
Aquatic ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
5.3
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Cyprinidae spp.
Moderate
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
3.84
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 )
3 = Unverified data of known source
Danio rerio Embryo
Moderate
Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
0.51
J4 J = Pesticide Action Network database (click here )
4 = Verified data
Daphnia magna
Moderate
Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
0.12
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 )
3 = Unverified data of known source
Daphnia magna LOEC
Moderate
Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
- - -
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)
- - -
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)
- - -
Aquatic Plants (free-floating, fonds growth, fresh) - 7 day (mg l⁻¹)
- - -
Aquatic plants (rooted, growth rate, fresh) - 14 day (mg l⁻¹)
- - -
Algae - Acute (growth rate, fresh; mg l⁻¹) (EC₅₀)
0.24
K3 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here )
3 = Unverified data of known source
Unknown species
Moderate
Algae - Chronic (growth rate, fresh; mg l⁻¹)
- - -
Mesocosm study data
NOEAEC mg l⁻¹
- - -
NOEAEC mg l⁻¹
- - -
Marine bivalves
- - -
HUMAN HEALTH AND PROTECTION
General
Property
Value
Source; quality score; and other information
Interpretation
Threshold of Toxicological Concern (Cramer Class)
High (class III) - -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 7220
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Low
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
1880
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rabbit
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
> 5.9
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
-
Other Mammal toxicity endpoints
Intraperitoneal LDLo = 1000 mg kg⁻¹
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Mouse
-
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
0.2
F4 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 )
4 = Verified data
JMPR 1995
-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
None allocated
F5 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 )
5 = Verified data used for regulatory purposes
JMPR 2002
-
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)
- - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)
- - -
Dermal penetration studies (%)
- - -
Dangerous Substances Directive 76/464
- - -
Exposure Routes
Public
-
Occupational
-
Mammalian dose elimination route and rate
Majority of dose eliminated in faeces
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
-
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
?Possibly, status not identified
A3 A = Chromosome aberration (EFSA database)
3 = Negative
;
B0 B = DNA damage/repair (EFSA database)
0 = No data
;
C0 C = Gene mutation (EFSA database)
0 = No data
;
D0 D = Genome mutation (EFSA database)
0 = No data
;
E3 E = Unspecified genotoxicity type (miscellaneous data source)
3 = Negative
Yes, known to cause a problem
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
?Possibly, status not identified
XNo, known not to cause a problem
Yes, known to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
XNo, known not to cause a problem
XNo, known not to cause a problem
XNo, known not to cause a problem
Eye irritant Phototoxicant  
?Possibly, status not identified
No data found  
General human health issues
Possible liver toxicant
IARC Group 3 carcinogen - not classifiable; US EPA - possible human carcinogen; Some sources dispute carcinogenicity
Handling issues
Property
Value and interpretation
General
Not explosive
IMDG Transport Hazard Class 9
CLP classification 2013
Health: H330, H361
Environment: H400, H410
WHO Classification
U (Unlikely to present an acute hazard)
UN Number
UN3082
Waste disposal & packaging
Packaging Group III (minor danger)
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
piperonyl butoxide
French
pipéronyl butoxyde
German
Piperonylbutoxid
Danish
piperonylbutoxyd
Italian
piperonil butossido
Spanish
butoxido de piperonilo
Greek
-
Polish
piperonyl butoksydu
Swedish
piperonylbutoxid
Hungarian
-
Dutch
-
Norwegian
-

Record last updated: 03/08/2025
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