UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

PC Code: 129093 

DP Barcode: 423209 

Date: October 28, 2014 

MEMORANDUM 

SUBJECT: 

FROM: 

THROUGH: 

TO: 

Response to Public Comments on the Registration Review: Preliminary Ecological Risk 

Assessment and Endangered Species Effects-Determination for Chlorfenapyr 

Stephen Wente, Ph.D., Biologist _...r-~ ~ /0 /z g ;;~ Environmental Risk Branch I f /. 

Environmental Fate and Effects Division (7507P) 

Office of Pesticide Programs ~~ 

Sujatha 

Meghan 

Sankula, 

Radtke, Ph.D.

Ph.D.

, 

, 

Acting 

Branch 

RAPL 

Chief .1 l~~ ~~~ .. ~ 10 

Environmental Risk Branch I 

Environmental Fate and Effects Division (7507P) 

Office of Pesticide Programs 

Margaret Hathaway, Chemical Review Manager 

Tom Myers, Team Leader 

Kevin Costello, Branch Chief 

Risk Management and Implementation Branch 2 

Pesticide Re-Evaluation Division (7508P) 

Office of Pesticide Programs 

In response to the "Registration Review: Preliminary Ecological Risk Assessment and Endangered 

Species Effects Determination for Chlorfenapyr" (D 420682), the Agency received two comments from 

The Center for Biological Diversity and an anonymous commenter. The purpose of this memorandum is 

to address these comments. 

Comment from Tbe Center for Biological Diversity 

Comment: "The draft ecological risk assessment for Chlorfenapyr concluded that "Based on incomplete 

exposure pathways for all chlorfenapyr uses, the Agency makes a No Effects (NE) determination for all 

listed species as well as a No Habitat Modification determination for all designated critical habitats for the 

currently registered uses of chlorfenapyr." The Center for Biological Diversity supports this 

determination and agrees that consultations under Section 7 are not required for this pesticide." 

EPA response: The Agency appreciates the acknowledgement of concurrence. 
2 

Comment from the Anonymous Commenter 

Comment: “Chlorfenapyr is registered for application to multiple sites with direct and indirect pathways 

to sewage treatment plants. These sites include crack/crevice/spot treatment on indoor residential sites 

(including as a bed bug treatment), food/feed handling areas, indoor commercial sites (including sewers), 

and indoor medical sites. Direct discharge would occur from sewer treatment; indirect discharges would 

occur from cleaning treated surfaces. Sewage treatment plants discharge to the environment, both to 

surface waters and to biosolids use locations (e.g., agricultural fields). Sewage treatment plants are not 

designed to degrade pesticides, which are commonly found in both effluents and biosolids. 

Chlorfenapyr is registered for application outdoors, including crack/crevice/spot treatment on outdoor 

residential sites. Rainwater falling on these outdoor locations could potentially wash chlorfenapyr and/or 

its degradates directly to surface waters, without any treatment, through municipal storm drainage 

systems (which are often composed entirely of impervious surfaces and hard drain pipes). 

The existence of these pathways indicates that the "no environmental exposure" analysis is not 

appropriate for a chemical with the above use sites. 

I encourage OPP to update its exposure assessment methodologies to more accurately reflect urban 

environments.1

” 

EPA response: The comment addresses two different, but related issues. The first points out that many of 

the listed chlorfenapyr uses “sound like” outdoor uses that could result in exposure to ecological 

receptors. The Agency addressed this concern for several of the uses that had confusing use site 

descriptions on pages 4 and 5 of the Chlorfenapyr Problem Formulation2

. 

...these use group names may appear to result in outdoor exposures to ecological receptors: 

 Household/Domestic Dwellings Outdoor Premises (Outdoor Residential) and 

Nonagricultural Outdoor Buildings/Structures (Terrestrial Non-Food Crop) – refers to 

uses that form a zone or barrier in the soil surrounding a building or structure (under 

concrete slab flooring and adjacent to basement walls) during construction and crack 

and crevice treatments that are used on existing buildings and structures. Preconstruction uses of chlorfenapyr result in the pesticide sequestered by soils under the 

floor of, or adjacent to the basement walls of, a building. Post-construction and crack 

and crevice treatments are limited to a 9.4 × 10-5 lbs ai per 2 sq. feet every four weeks. 

Therefore, assuming 4 sides of a building are treated with sides 10' high by 100' long 

(4000 ft2

) would result in a maximum treatment of 0.18 lbs ai to the building. However, 

EFED believes such applications would be unlikely to create a significant exposure 

pathway to ecological receptors because: most structurally sound buildings have far 

fewer cracks and crevices than the maximum application rate allows; much of the 

applied pesticide would be retained inside the crevice or crack; and much of the pesticide 

that was dislodged from its application site would be retained in any soil and/or 

landscaping at the base of the treated wall. 

 

1 http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2010-0467-0022 2

 USEPA. Registration Review – Problem Formulation Revised Based on Public Comments for Ecological Risk, 

Environmental Fate, and Endangered Species Assessments for Chlorfenapyr (PC Code 129093; DP Barcode 

383511). Office of Pesticides Programs. 10/28/2010. 
3 

 Sewage Systems (Aquatic Non-Food Industrial) – is a crack and crevice treatment that is 

used in cracks in the concrete slab flooring around floor drains. The intent is not to 

discharge the chemical to the sewer system but, rather, to prevent ground-dwelling 

insects from entering a building through cracks in the flooring around the drain. The 

label specifies that the drain must lead to a sewage system (and thus presumably, would 

be greatly diluted if some of the pesticide went down the drain) to prevent the use of the 

chemical around drains that may discharge immediately outside of the building (where 

relatively little dilution might occur). 

 Zoos (Indoor Non-Food) – is also a crack and crevice use that is used on buildings 

enclosing zoo animals. 

The commenter’s second issue conflates the Agency’s use of the phrase “incomplete exposure pathway” 

with the idea of no (zero) exposure. The Agency uses the phrase “incomplete exposure pathway” to 

indicate that any potential exposure to an ecological receptor (non-target organism) through registered 

(legal) uses of a pesticide would be far below the level necessary to cause harm to that receptor. For 

example, use of chlorfenapyr in a crack and crevice treatment around floor drains likely results in small 

and infrequent releases of chlorfenapyr to wastewater treatment plants (WWTP) when the floor is 

washed. However, the exposure to aquatic life in the receiving water from a WWTP or to terrestrial 

organisms from land applied WWTP solids would most likely be far below that necessary to cause harm. 

Again as stated in the Chlorfenapyr Problem Formulation, based “on incomplete exposure pathways for 

all chlorfenapyr uses, the Agency makes a No Effects (NE) determination for all listed species as well as 

a No Habitat Modification determination for all designated critical habitats for the currently registered 

uses of chlorfenapyr.”