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UNITED 

### STATES ENVIRONMENTAL PROTECTION 

### AGENCY WASHINGTON 

### D.C.,20460

OFFICE OF CHEMICAL SAFETYAND POLLUTION PREVENTION

PC Code: 109709 DP Barcodes: 4t527 8, 4tgL7 5

Response 

### to Public Comments Received on 

### the Preliminary Ecological Risk Assessment and Endangered Species Effects Determination Conducted 

### for the Registration Review 

### of Metofluthrin May 

### L5,20L4

MEMORANDUM

SUBJECT:

FROM:

TO: Linda 

### Arrington, Branch Chief

Risk Management and 

### lmplementation Branch V Pesticide Re-evaluation Division (7508P)

The 

### Metofluthrin Preliminary Work Plan dated June 2L, 2013 and published in docket number EPA-HQOPP-2012-0105 summarized 

### the preliminary conclusions made in 

### the April 

### t6,2OL3 ecological risk assessment and endangered species effects 

### determination. The risk assessment noted 

### that for 

### the currently registered uses, 

### metofluthrin is released into 

### the air as a vapor 

### through passive dissipation, heat-driven or fan driven evaporation, and 

### that metofluthrin was expected 

### to dissipate rapidly through a combination 

### of degradation and 

### dilution by 

### the large volume of air into which 

### it is released.

Based on 

### the available data, 

### the currently registered use patterns, and conservative assumptions regarding exposure, none 

### of EPA's Levels of Concern were exceeded for fish, aquatic invertebrates, birds, or mammals. Given 

### the relatively limited area of effect around 

### the metofluthrin dispensing devices (up 

### to 5 meters), 

### the likely setting 

### of use (i.e., in backyards and 

### other areas around people), 

### the short half-life of 

### metofluthrin in air (ranging 

### from 1.7 

### to 1.9 hours), and the fact 

### that the non-target invertebrates 

### would be exposed 

### to the metofluthrin only by chance [unlike the target species (i.e., mosquitoes 

### that track humans)1, 

### the probability of impacting endangered invertebrates was low.
Further, 

### the risk assessment concluded 

### that due 

### to a combination 

### of low exposure and relative insensitivity 

### to the active ingredient (for many taxa), risks 

### to non-target organisms were not expected. Because direct adverse effects were not expected 

### for birds, reptiles, amphibians, mammals, fish, 

### or aquatic invertebrates, and there was no reasonable expectation of effects 

### to plants or 

### terrestrial invertebrates, a No Effects (NE) determination 

### for all Federally-listed threatened/endangered species
was made for 

### the currently registered uses 

### of metofluthrin. This determination was supported by 

### the Office 

### of Pesticide Programs' Science Policy Council/Risk Management Forum De Minimis Subgroup. 

### lt 

# 3;J;jffi:;,:lHlSHl,' rlrcf zDt/

Environmental Fate and Effects Division (75O7Pl

### 2

was also determined that for the currently registered uses, no Habit at Modification was likely for designated critical habitats.
The Preliminary Work Plan requested public comment on the ecological risk assessment / endangered species effects determination . C omments were received from the San Francisco Bay Regional Water Quality Control Board (8/26/2013), the Central Valley Regional Water Quality Control Board (8/26/2013), and the California Stor mwater Quality Association (8/23 /2013 ). Comments from all three organizations were similar and are summarized below. Over all, the commenters felt that the data and modeling required of other pyrethroids undergoing registration review shou ld also be required for metofluthrin , metofluthrin’s environmental risk assessment should include a quantitative assessment of the same lev el of rigor as the risk assessments for all other pyrethroids, and that all pyrethroids should be reviewed together as a group.
Summary of Comments

 Request that the de minimis environmental risk determination be rescinded and a full risk assessment be co nducted.

 Based on experience with other pesticides, the outdoor misters and indoor bedbug treatments are likely to cause and/or add to the pyrethroid toxicity in urban waterways.

 Metofluthrin should be considered cumulatively with the other pyrethroids be cause toxicity is additive within the class.

 The environmental risk assessment should consider that some fraction of the mist will deposit on outdoor surfaces where it can then be transported to storm drains or directly to water bodies.

 Environmentally sig nificant amounts of metofluthrin will be released to indoor drains during washing of linens that have covered treated mattresses and of clothes worn by people using the mister and the clip

- on vaporizer.

 Aquatic toxicity data for known sensitive species, i. e., Hyalella Azteca, Americamysis bahia, Chironomus dilutes, and Leptocheirus plumulosus should be required and incorporated into the risk assessment.

 Experimental photodegradation rates for air and surfaces are needed.

 An anaerobic sediment degradation rate is needed.

 Modeling of urban runoff from impervious surfaces and turf should be completed.

 Modeling down

- the

- drain pathways to wastewater treatment plants should be completed.

 Analytical methods for water and sediment matrices that detect metofluthrin at environmentally relevant concentrations should be required from the pesticide manufacturer.

 Water quality monitoring data should be required.
The Environmental Fate and Effects Division has carefully evaluated the comments received during the public co mment phase of the registration review process for metofluthrin and continues to believe that the toxicity and environmental fate data for the compound, taken together with the registered uses strongly support the de minimis finding and the no effect deter mination. Even considering highly conservative exposure scenarios, we did not find exceedences of EPA ’s levels of concern.

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While we agree with the commenters that it is appropriate to schedule the evaluation of all the pyrethroids together as a chemical class (which we are doing in Registration Review) , each chemical in this class has its own unique hazard and exposure profile, and thus risk. Therefore, consistent with EPA’s ecological risk assessment guidelines, it would not be appropriate to conduct t he exact same type and level of risk assessment for all of the pyrethroids, because of the differences between them.
Should the use pattern for metofluthrin change and/or expand , a n updated r isk assessment would be conducted, and the de minimis decision revisited

.