Clare Thorp, Ph.D.

Senior Director

Human Health Policy

CropLife America

FIFRA SAP May 21-23 2013:

EDSP Tier 1 Screening Assays and 

Battery Performance
• A not- for- profit national trade organization 

representing the nation’s developers, 

manufacturers, formulators and distributers of 

plant science solutions for agriculture and pest 

management in the U.S.

• Member companies produce, sell and distribute 

virtually all the crop technology products used 

by American farmers.

• Member companies have generated the data 

being assessed by this SAP

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CropLife America
Current Pesticide Testing and Regulation

A new pesticide product takes ~10 years to develop. 

Regulatory testing involves 110+ tests per compound to 

meet the data requirements necessary for registration.

Pesticide testing is as extensive than that conducted for 

pharmaceuticals

Every pesticide currently registered in the US undergoes 

review every 15 years.

EPA can require further testing when more data is required.

Tier 1 battery: 

$750k - $1m per compound 

2+ years to complete

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The data requirements cover:

•Product performance

•Biological efficacy

•Plant health

•Physical and chemical characteristics

•Wildlife and aquatic organisms (Ecotox)

•Non-target organisms

•Environmental fate

•Mammalian toxicology

•Residue chemistry

•Spray drift

•Re-entry Protection 4
Toxicological testing:

• Acute: 

 Single exposure, 

 High dose, 

 Short duration (lethal)

• Sub Chronic: 

 Repeated exposure, 

 Intermediate Dose, 

 Moderate Duration (sub lethal – toxic and non toxic doses)

• Chronic:

 Multiple exposures, 

 Low dose, 

 Long duration (multi generational)

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Mammalian Toxicology Data Requirements (global)

Acute Toxicity:

• Oral

• Dermal

• Inhalation

• Skin irritation

• Eye irritation

• Skin sensitization

Repeat Dose Toxicity:

• Rangefinders (rat, mouse, dog)

• 90-day oral rat

• 90-day oral mouse

• 90-day oral dog

• 28-day dermal

• 28/90-day inhalation

Long-term Toxicity:

• 2-year rat

• 18-month mouse

• 1-year dog

Reproduction & Development:

• 2 Generation reproduction

• Rat developmental toxicity

• Rabbit developmental toxicity

Acute :

• Oral

• Dermal

• Inhalation

• Skin irritation

• Eye irritation

• Skin sensitization Neurotoxicity:

• Acute neurotoxicity

• Subchronic neurotoxicity

• Developmental Neurotoxicity 

(conditional)

Immunotoxicity:

• Rat and/or mouse immunotoxicity

Metabolism:

• ADME single and multiple

Other:

• Additional studies as necessary to 

address specific findings (e.g., mode 

of action, relative sensitivity)
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Required for global pesticide registration: 

Avian Toxicity: • Acute oral (2 species)

• Acute dietary (2 species)

• Reproduction (2 species)

Toxicity to Aquatic Organisms:

• Acute freshwater fish (2 species)

• Acute marine fish

• Early Life stage freshwater fish

• Acute freshwater invertebrate

• Acute saltwater invertebrate

• Chronic freshwater invertebrate

• Acute mollusk(estuarine)

Toxicity to Bees:

• Honeybee acute contact toxicity

• Honeybee acute oral toxicity

• Honeybee brood toxicity

Toxicity to Non-Target Plants • Algae

• Aquatic macrophyte

• Terrestrial plants seedling emergence and vegetative vigor 

toxicity

Additional studies (conditionally 

required and/or required by 

other regulatory bodies: )

• Additional avian species

• Additional algal species

• Early Life stage saltwater fish

• Fish bioconcentration

• Fish full life cycle

• Aquatic insect

• Sediment dwelling species

• Toxicity to non-target insects (2-4 species)

• Acute and Chronic Toxicity to earthworms

Ecotoxicology Data Requirements
 Use all existing data to identify potential endocrine activity 

and to guide the selection of endocrine- specific tests

 Selective use of Tier 1 assays: Not all 11 assays may be 

necessary

 Staged testing for chemicals: To allow decisions to be made 

on specific assays that may not be required and therefore may 

be waived. Waivers may be assessed using OSRI.

 Select dose level carefully:

–confounding effects 

–overt toxicity 

–stress on the model system (in vitro or in vivo)

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Towards an integrated testing and evaluation program:

Not by rote, but by requirement 
 EPA not issue new Tier 1 screening orders for additional 

substances (List 2) before the Agency has evaluated the 

lessons learned from the initial List 1 substances

 EPA deliberately evaluate the Tier 1 screening results, 

alongside the Tier 1 assays, “functionally equivalent data,” 

and “other scientifically relevant information” to identify the 

most effective and efficient path forward

 Certain methods need to be upgraded and their 

corresponding test guidelines revised prior to issuing new 

test orders 

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Moving Forward: Suggestions
Additional Points : Communication

Global implications of the EDSP

 Continue communicating to the public on all stages 

of the EDSP

Ensure descriptors of “endocrine disrupters” are 

consistent across the agency and in line with the 

EDSP definition

March 2013 CLA/ECPA Meeting
Thank you for your attention

Clare Thorp, Ph.D.

Senior Director, Human Health Policy

cthorp@croplifeamerica.org