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composting of chlorfenapyr-treated material. Therefore, EFED no longer considers composting 

to be a viable exposure route for chlorfenapyr to ecological receptors. 

A second concern of EFED’s in the preliminary problem formulation dealt with chlorfenapyr being 

applied to soil underlying a concrete slab prior to the slab being poured (during construction) 

(EPA Reg. No. 000241-00392). In the event that a major rain event occurs after treatment and 

prior to pouring of the concrete slab, there is a potential for exposure to chlorfenapyr in adjacent 

areas via runoff from the use site. EFED concluded that such exposure is possible because the 

label does not specify that the amount of time between application of chlorfenapyr and the 

pouring of the concrete slab be minimized. As of the time of this document, the label language 

has not been modified. EFED continues to believe that such language should appear on the label. 

However, at this time, EFED does not believe this exposure route is sufficient to warrant the 

collection of additional fate and effects data or the development of an ecological risk assessment. 

BASF Comment: 

The currently registered uses for chlorfenapyr in the United States, being primarily indoor, are 

not expected to result in significant exposure to endangered species. Therefore, an endangered 

species assessment is not needed at this time. (Page 4). 

EFED Response: 

Because the composting language has been modified on label EPA Reg. No. 000241-00374, 

EFED concurs that an endangered species assessment is not needed at this time as part of this 

Registration Review. 

BASF Comment: 

Following discussions with the chemical review manager, BASF agreed to remove composting 

directions from chlorfenapyr labels and subsequently submitted revised labeling to the EPA OPP 

Registration Division on August 10, 2010 to remove the composting directions from the current 

label (Page 4). 

EFED Response: 

EFED has received a copy of the revised label restricting the composting of treated plant 

material. EFED will revise the Problem Formulation in light of the restriction on composting. 

BASF Comment: 

The currently registered uses for chlorfenapyr in the United States, being primarily indoor, are 

not expected to result in significant exposure to endangered species. Therefore, an endangered 

species assessment should not be needed (Page 5). 
3

EFED Response: 

EFED agrees that an endangered species assessment is not needed at this time as part of the 

chlorfenapyr Registration Review because chlorfenapyr is primarily registered for indoor, 

underground, or crack and crevice uses, which would not be expected to result in significant 

exposure to endangered species. 

BASF Comment: 

Per 40CFR 158.630, sediment testing is only required if the product is expected to enter the 

environment in significant concentrations, either by runoff or erosion, because of its expected 

use or mobility pattern. Based on its current uses in the United States and its mobility pattern, 

chlorfenapyr would not be expected to enter the environment in significant concentrations (Page 

5). 

EFED Response: 

Chlorfenapyr is primarily used indoors, underground or as a crack and crevice treatment and is 

not expected to enter the environment in significant concentration; therefore, sediment testing is 

not required at this time for this Registration Review. 

BASF Comment: 

Per 40CFR 158.630 acute toxicity estuarine and marine organism acute toxicity data is not 

required for indoor uses. Based on its current uses (primarily indoor and/or structural) in the 

United States and its mobility pattern, chlorfenapyr would not be expected to enter the 

environment in significant concentrations (Page 5). 

EFED Response:

Chlorfenapyr is primarily used indoors, underground or as a crack and crevice treatment and is 

not expected to enter aquatic environments in significant concentration; therefore, an acute 

toxicity estuarine and marine study is not required for this Registration Review. 

BASF Comment: 

Per 40CFR 158.630 Fish early-life stage (freshwater) data is not required for indoor use. Based 

on its current uses (primarily indoor and/or structural) in the United States and its mobility 

pattern, chlorfenapyr would not be expected to enter the environment in significant 

concentrations (Page 5). 
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EFED Response:

Chlorfenapyr is primarily used indoors, underground or as a crack and crevice treatment and is 

not expected to enter aquatic environments in significant concentration; therefore, a freshwater 

early-life stage study is not required for this Registration Review. 

BASF Comment: 

BASF has previously submitted multiple soil methods (MRID 43492850). In response to this 

summary document BASF submitted multiple additional methods for both soil and water to EPA 

on August 4, 2010 (Page 5). 

EFED Response:

Based on the new label use restriction on the composting of treated plant material the Agency is 

no longer requesting the Registrant submit soil and water methods. 

BASF Comment: 

Following discussions with the chemical review manager, BASF agreed to remove composting 

directions from chlorfenapyr labels and subsequently submitted revised labeling to the EPA OPP 

Registration Division on August 10, 2010 to remove the composting directions from the current 

label. Therefore, a study evaluating chlorfenapyr degradation in compost should not be needed 

(Page 5). 

EFED Response:

The label use restriction prohibiting the composting treated plant material removes the need to 

evaluate chlorfenapyr degradation in compost. 

BASF Comment

In EFED’s Preliminary Problem Formulation (PF) for Ecological Risk, Environmental Fate, and 

Endangered Species Assessments for Chlorfenapyr (PC Code 129093; DP Barcode 373109), the 

following potential exposure pathways from chlorfenapyr-treated compost was outlined. 
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Figure 1. Potential exposure pathways from chlorfenapyr-treated compost 

(EFED doc. May 11, 2010, pg. 7). 

BASF has submitted a revised label for chlorfenapyr which removes composting as an 

acceptable practice. Therefore BASF has modified the PF reflecting the removal of compost 

from the label. The modified PF can be found in Figure 2. 

Figure 2. Revised potential exposure pathways from chlorfenapyr based on the modified label 

submitted by BASF. 

EPA in its Preliminary Problem Formulation' (PF) for Ecological Risk, Environmental Fate, and 

Endangered Species Assessments for Chlorfenapyr (PC Code 129093; DP Barcode 373109) 

document, the Agency requested a series of studies to address concerns in their PF. The 

requested studies are as follows: 

1. Guideline 850.4100, 41500, 4400, 5400 - Aquatic and Terrestrial Plant Toxicity. 

2. Guideline 850.1735 and 850.1740 - Whole sediment: freshwater and marine invertebrates. 

Chlorfenapyr applied to plants 

grown in greenhouse 

Edible portion harvested 

from plants (Health Effects 

Division Assessment) 
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3. Guideline 850.1075 - Fish Acute LC50 RBT for degradate CL357806. 

4. Guideline 850.1025 - Estuarine/Marine Acute Invertebrate LC50 Oyster. 

5. Guideline 850.1400 - Fish ELS study. 

6. Special Study - Evaluation of chlorfenapyr in compost. 

BASF has revised the PF based on our newly revised label. Since the PF has been revised based 

on the new BASF label, we no longer see any basis for the studies requested. BASF provides the 

following rationale for the dismissal of the requested studies. 

1. Guideline 850.4100, 4150, 4400, 5400 - Aquatic and terrestrial Plant Toxicity. Based on the 

40 CFR code requirements found on Table 158.540, these studies are not required for 

greenhouse use. 

2. Guideline 850.1735 and 850.1740 - Whole sediment: freshwater and marine invertebrates. 

Based on the 40 CFR code requirements found on Table 158.490, these studies are not 

required for greenhouse use. 

3. Guideline 850.1075 - Fish Acute LC50 RBT for degradate CL357806. Based on the 40 CFR 

 code requirements found on Table 158.490, these studies are not required for greenhouse use. 

4. Guideline 850.1025 - Estuarine/Marine Acute Invertebrate LC50 Oyster. Based on the 40 CFR 

 code requirements found on Table 158.490, these studies are not required for greenhouse use. 

5. Guideline 850.1400 - Fish ELS study. Based on the 40 CFR code requirements found on Table 

 158.490, these studies are not required for greenhouse use. 

6. Special Study - Evaluation of chlorfenapyr in compost. Since the revised BASF label does not 

 have a labeled compost use, we no longer see any basis for this request. 

EFED Response: 

Based on the revised label use restriction prohibiting the composting of treated plant material the 

Agency is no longer requesting the studies listed immediately above. 

PCRM Comment:

We also wish to comment on the fish testing proposal "(850.1075) Acute Fish Toxicity 

Study" that the EPA submitted for Chlorfenapyr. We believe that the number of animals used 

can be reduced by following an acute threshold or "limit test" approach. This approach was first 

pioneered on the observation that fish are rarely more sensitive than algae and daphnia." The fish 
7

median lethal concentration (LC50) test is replaced with an acute threshold test in which fish 

testing would be performed at one concentration only (the lowest EC50 concentration obtained 

with previous algae and daphnia testing). A version of this approach has been adopted by the 

OECD as a guidance document and they will be publishing the final one shortly," 

While that approach will not satisfy the EPA's data needs, in previous comments EFED scientists 

have illuminated a potential way forward that may help to reduce fish testing in some cases: The 

definitive LC50 test for a formulated product could be waived if a limit test [is] performed. This 

strategy is based on the predicted environmental exposure. The limit test dose is set not 

arbitrarily but is unique to each case and is set in order to ensure that predicted exposure will not 

reach the Agency's Level of Concern. If fewer than 50% of fish die at the calculated single-dose 

"limit," the full LC50 test would produce an LC50 result that is higher than the LOC, ensuring 

that the environmental exposures will not be acutely harmful. If the limit test is unsuccessful--

that is, if more than 50% of fish die at that dose level, a full 96-hour LC50 test would be 

required. 

Clearly, this approach is not right for all chemicals, as following this approach for substances 

that are expected to be more acutely toxic than the LOC would in fact use more animals. Existing 

information and QSAR models can help determine whether this strategy would reduce the 

number of fish killed. We encourage the registrant to determine whether this strategy is 

appropriate for this situation. 

We also encourage the use of (Q)SAR data either in place of, or addition to, the fish 

experimental data. When correctly applied, (Q)SARs can feasibly replace in vivo data in some 

instances; requesting (Q)SAR data in addition to in vivo data would increase Agency and 

registrant comfort and confidence with the use and evaluation of data from such methods. 

EFED Comment:

Based on the revised label use restriction prohibiting the composting of treated plant material the 

Agency is no longer requesting these studies.