# Proposed Registration Decision for the New Active Ingredient Hexanoic Acid PC Code: 041201

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### S ummary This document announces that the Environmental Protect io n Age n cy (EPA) ha s completed it s eva lu a ti on o f the new bio c h e mical activ e in gredie nt , h exa n o ic ac id , and ha s conc lud ed that it mee t s th e reg ulatory and safety s tandard s und e r the Federal In sect i c ide , Fun g icide a nd R o d e nti cide Act (FIFRA). One product i s proposed for r eg istrati o n unde r Section 3(c)(5) of FIFRA: an end- u se product (EP), BG- Swee t s cent , conta inin g hexanoi c ac id for non-food u se. Hexanoic acid i s intend ed for fo rmul ation into end-u sc products that attr ac t a broad ran ge o f mo s quitoes ( b y mimickin g o d o rs e mitted from human sk in ) into traps where they die , when u sed in accordance w ith labe l directions. H exano ic ac id , a l so kn ow n as capro ic ac id , i s a member of a g roup of s hort- c h a in ed lin ear fatty acids 

### (i.e., h e ptanoic , octano ic ac id ). 

### It i s a fa tt y acid found naturally in m a n y pl a nt and animal fat s and i s s tructurally s imilar to octano ic acid, whic h ha s a lready been as sesse d b y the A ge n cy . As a result of it s natura l occu rr e nc e in va ri o u s plant and animal fats and o il s , includin g coconut and palm oil , vanilla , and cow and goat 's mi l k, in 1977, the Food a nd D rug Admi ni stration ( FD A) gave b road approval of fatty acid as an add iti ve in foods

. In c lud ed in that ap proval is the g roup of s tr aig ht chain m o n obas ic carbo xy li c ac id s that inc l udes he xano ic acid. Hexanoic acid is con s idered b y FDA to be GRAS as a synthe ti c flavoring food a dditive (2 1 CF R 1 72 .51 5) and h as been app r ove d for use in washing and p ee lin g of fruit s and vegetables (2 1 CF R 17 2.3 15). H exano i c acid is currently used as an additive in a wi de range of foods includin g , nuts, cocoa , dairy produc t s, savory vegetab le s , and m eats. Hexanoic acid has a lso been determined to be exe mpt from th e require m en t for a tol e ra n ce by the Age n cy when used as a fragrance age nt (40 CFR 1 80.940) with an upper limit f o r u se in pestic id e formul a ti o n s of l 00 ppm. As a bi opcs ti c id e, hexan o ic ac id i s classifi e d as an attractan t for mo s quitoes . The s mell of he xano ic ac id i s that of goat cheese or sweat but in combination with lactic acid a nd ammonium bicarbonate effec tively a ttracts m osqu it oes. Attractant s , as well as repellents, have spec ifi c st imul ato ry effec ts o n in sect recep tor n eurons a nd can be seen as modulators of mosquito odorant r ecep tor ac ti v ity (o lfactor y receptor neuro n s), s timulatin g olfac to r y and gustatory receptors o n in sec t a nte nn a. Th e proposed product , B G-Swee tsce nt , is enc lose d in a Tyvek®sac h et as a mi xture of ammonium bicarb onate and porous polyme r pe ll ets that are load e d w ith lactic and hexanoic acid. The

**Tyvek ~**  membrane protec t s the ammonium bicarbonate a nd polymer pellets from water and a ll ows th e vo latile compounds to dif fuse ou t. The porous polyme r pellets act as a controlled re lease m ec hanism for th e vo latil e compound s, lact ic and h exano ic acid , pro v idin g a non-liquid pre se nt a ti o n of the chem icals. Ammonium bic arbonate i s th e precursor f o r ammonia as it s low ly decomposes into ammonia , carbo n dio xide, a nd wate r at a mbi e nt te mperat ures. The lure is proposed to be used in va ri ous types of m osqu it o trap s an d i s replaced after 8 weeks o f use. Th e u se rs a re in s tructed to NOT o pen th e e n close d sac h e t s thu s preventing expo s ure to the p r oduct. R a the r, users are in s tructe d to in sert the sac het into a pest ic id e de v ice ( trap ) a nd th e refore , u se of the product do es n o t re s ult in direc t exposure to th e u se r. The Tyvek ® sac he t is designed to release the scent of hexanoic ac id slow ly ove r a pe r iod of 8

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### weeks as a lure for mosquitoes. This slow- release of hexanoic acid vapor w ill r es ult in very low conc e ntrations in the outdoo r air s urroundi n g the mosquito trap. 

### 2 .0 B ac kg ro und The Biochemical Classification Comm itt ee (BCC) classified hexanoic acid a s a biochemical pesticid e du e to its natural occurre nce. hi sto ry of exposure to humans and th e environment wit hout toxicity. and its nontoxic mode of action to the target ed pest. The use or hexanoic acid is s imilar to previously registered insect attractants in that it is use d as a se lective attractant to manage s pecific in sects (i.e

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### mosquitoes). It is delivered from a s tationary trap , as a slow relea se vo ltile compound that a ttracts the targeted in sec t into the trap where they naturall y die. On April 20, 2015, EPA r ece ived an application from Teclu10logy Sciences Group , Inc

. . on behalf of Bi oge nt s AG for the reg is trat ion of a non-food use mosquito attrac t ant containing the proposed ne w active ingredient , hexanoic acid. On August 25. 20 15. EPA announced r eceipt of an application to register a product containing the proposed new active ingredient. hexanoic acid ( 80 FR. umb er 164. pages 51560- 51561 ). No comments were recei ve d in response to the announcement (Document ID : EPA-HQ-OPP- 20 15-0547). 

### 3 . 0 E v a luati o n In eq1luating a pe s ticide rc g i tration application. the EPA

**ass~sscs** 

### a wide \arict y of pesticidespecific information in<.:ludin g " ·here and ho " the pesticide is used

. enYironmental fate (i.e

.. 

### " ·hat happens to the pesticide once it" s applied), and toxicity s tudies (i.e

.. 

### cllect s on humans and other non-target o rgani sms) to uctermine th e lik e lih ood or ath·e r sc effec ts (i.e

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### ri s k) from exposures assoc ia ted with the proposed use or the prouu<.:t. Ri s k assess ment s arc ucwlopeu to cn1luate the environmental fate of the compound as well as ht)\\ it might affcc..:t a \\'ide range of non - target orga ni s ms including humans and terre st rial and aquatic " ·ildlifc (p lants and animals). Based on th ese assessments. EPA eva lu a t es and appro\'es language (()reach pes ti cide label t o ensure that the directions for use and safe ty meas ures arc app rop riate t o miti gate potential risk. In this way . the pesticide' s label helps to communicate essential limit ations and mitigation!:> that arc nece ssary for public safety. I t is a riFRA , ·io lation to use a pestieiue in a way that is inconsistent " ·ith the label. The human health and environmental ri sk assessments ( in cluding an endangered s pecies assessment) s upporting this proposed decision as well as th e draft labeling can be found in the regulatory docket (Document ID: EPA- HQ-OPP-20 15-054 7). 3. 1 Assess m e n t o f Ri s k to Hum a n Hea lth 

### EPA require s a wide range of s tudie s in order t o assess a pe s ticide. The toxicological databa se is considered comp lete for cha r acte ri z in g hazard and assessi ng ri sk from hexanoic ac id for nonfood uses. The applicant ha s adequately addressed a ll data req uire me nt s for the proposed use or hexanoic acid w ith scientific rationales suppo rt ed by data/information from open literature.

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### 3.1.1 Toxicity The avai lable data/information indicate that techn ic a l- g rad e hexanoic ac id is acutely toxic (c lassified as Toxicity Category I

- signal word Danger) for primary eye irri tation and primary s kin irrit ation routes of exposure. ln terms of acute inhal ation exposure , the LC50 was > 1.368 mg/ L , which corresponds to an EPA Toxicity Category Ill for the inhalation route. For acute dermal exposure, the compound is classified as Toxicity Category IV

. In forn1ation submitted in support of hexanoic acid show that it is not a dermal sensi ti zer. Acute toxicity data requirements fo r the end use product we re addressed w i th rationales based on th e fact that there will be no exposure to the end use product. Eye contact is not anticipated when u s ing and/o r handling the product as directed on the proposed product label since the active ingred ient is packaged into granu les that are contained in a heat-sealed Tyvek sachet (designed to not rip or tear) a nd furthe r placed inside a trap. Likew ise, the toxicity category for eye irritation of the EP, wou ld not be expected to be higher than toxicity category I of the technical material because of the lower concentration of hexanoic ac id in the end-use product (8 .8 2 % w/ w) compared to that of hexanoic acid as its active ingredient (98 

### % w/w). Therefore , given th e lack of exposure that is expected, proposed precautionary labeling commensurate with Caution is app r opriate. Subchronic o ral toxicity data requirements were satisfied through information from the open sc ientific literature

. Two dietary feeding stud i es we r e assessed and found to collectively satisfy the subclu·onic ora l data r eq uirement. No adve rse effects were noted in either study as a result of exposure to hexanoic acid. In a prenatal developmental toxicity study on octanoic acid, a fatty acid closely related to hexanoic acid, the No Observed Adverse Effect L evel (NOAEL) for developmental toxicity is I , 125 mg/ kg/day , which is the maternal L owest Observed Adve rse Effect Level (LOAEL) for reduced body weight gain and respiratory effects that included rales and dyspnea. Fetotoxicity was observed at 1 , 500 mg/kg in the form of a reduced number of live pups on postnatal day 6 compared to the contro l s . Subchronic dermal and inhalation toxicity data requirements were waived based on lO\ V likelihood of ex posure via these routes. More detail on ant icip ated exposures to hexanoic acid re sulting from the proposed use pattern is provided below. 

### 3.1.2 Expo s ure and Risk The propo sed use of hexanoic acid is not likely to result in significant levels of oraL dermal or inhalation exposure due to a combination of th e product fonnulation and packaging. The hexanoic acid is infused into porous polymer pellets w hich are then enclosed in a TyvekOi: sac het. The Tyvekqy membran e protects the polymer pellets from wate r and a ll ows low levels of th e vo latile hexanoic acid to slow ly diffuse out over a period of 8 weeks

. These sachets are placed i nside a trap device further limiting the potential for human exposure. As mentioned earl ie r , hexano ic acid has been approved as a food addi ti ve, for use in food processing and can be found as a natural component in many animal and plant fats / oils. These exposures are co n s id ered safe by FDA. However, the use of hexanoic acid as a mosquito

Pag e 4 of7a ttrac t a nt is n o t co n s id e red a f oo d u s e and o ral ex p os ures to hexan o ic a cid as a r es ult o f r es idu es in f ood o r drinkin g wate r f ro m thi s p esticidal u se are n o t ex p ec te d. D e rm a l co ntact ·w ith th e p o ly m e r p e ll e t s is n o t a nti c ip a te d s ince th ey a r e e ncl ose d in T yve k k sac he t. In addition , th e ex t e nt o f contact w i th th e sac he ts is limited to th e pl ace m e nt of th e product in a trap and re moval of the spent sachet e ig ht w e eks l ater further limitin g th e neg l ig ibl e p o t e ntial for dem1 a l ex p os ure , T he s lo w-re lease o f h exan o ic acid vapor will res ult in ve ry lo w air con ce ntr a ti o n s in th e o utd oo r a ir imm e di a tel y s urro undin g th e trap . No s i g nifi ca nt re p eat inhal a ti o n ex p os ure to th e acti ve in g red ie nt as a g a s . va p o r o r ae ros ol i s anti c ip a te d g ive n th e lo w l eve l s bein g re leased from th e p o ly m e r pellet s and th e ra pid dilution o f th ese lo w leve ls in a mbi e nt o utd oo r a ir. Furth e r. to prov id e a dditi o n a l co ntex t , th e maximum a nti c ipa t e d leve l of h ex anoi c ac id in th e pro p ose d e ndu sc pro duct i s 34 ppm w hi c h is s ignificantly l ess th a n th e maximum all o w a b l e limit for it s u s c as a fr ag rance of 

### 100 ppm. C on s id e ring that the product is d e si g ned to relea se th e 34 ppm ov e r th e co urs e of 

### 56 day s th e A ge nc y b e lieves that expo s ures from this use pattern wou ld be s ub s t a nti a ll y low e r th a n a ppro ve d fragranc e e xp os ures . B ase d o n th e low p o t e nti a l f o r o ccupat ion a l , res i de nti a l h a ndler or b ys ta nd e r ex p os ure v ia th e o ra l. de m1 a l and inh a la ti o n p a thw ays, th e Age n cy h as d e t e rmin e d that a qu a ntit a ti v e ri s k assess m e nt i s n o t n ee d e d fo r h ex anoic acid and th a t ri s k s o f ad ve r se ef f ec t s to hum a n s are n o t a nti c ip a te d ba se d o n th e pro p osed use patt e rn. 

### 3. 2 Ec ol og i c al Ri s k Assess m e n t a nd Co nclu s io n s T he av ailabl e dat a i s ad e qu a t e to a s sess the e col og i ca l e ff e ct s of h e x anoi c ac id a nd to conduct an eco log ical ri s k assess m e nt. A ll n o n-targe t o rgani s m tox ico lo gy and e n v iro nm e nt a l f a te d a t a req uire m e nt s ( per 

### 4 0 CfR 

### 15 8. 2 0 60 ) ha ve b ee n sati s fi e d th ro ugh c it a ti o n o f d a t a/inf o rmati o n f ro m th e o pen sc i e ntifi c lite ra ture. In condu c tin g it s ri sk assess ment. th e s tru c tur a l s imil a rity o f h exa n o i c a cid to he pt a n o ic, oc t a noic and n o nan o i c ac id ser ved as th e b as i s f o r all ow in g th e Age n cy to u s c tox ico logy a nd e colo g ical data and assess m e nt s from th ese re late d co mp o und s as s urr og ate data ( U SE PA

. 

### 2 009). As p a rt of the A ge nc y's reg is trat ion review deci s i o n for octanoic acid in 

### 2 009, a reg i s te re d f a tt y ac id clo se ly rel a te d to hex anoic acid , th e A ge n cy c o nducted a rev i ew o f th e sc ie nti f ic dat a b ases a nd o th e r re leva nt inf o rmati o n and wa ived a ll ge n e ric e cotox ic ity a nd e n v iro nm e nt a l fa te data re quire m e nt s f o r thi s c hemic a l. F a t ty a c i ds n o rm a ll y are m e tab o li ze d

. fo rmin g s impl e co mp o und s th a t ser ve a s e nerg y so urces and s tru c tural c o mp o ne nt s u sed in a ll li v i n g ce ll s . T he Age nc y d e te rmin e d that an ecol og ica l ri s k assess ment w a s n o t nee d e d as part o f thi s d ec is io n (U SEPA. 

### 2 0 09). A r e view of the avail a bl e s cientific literature t o r he xanoic acid indicate d that hexano ic acid is prac ti c all y non-toxic to fi s h and aquatic in ve rt e bra t es . In ad diti o n to th e l ack o f tox ic ity to n o n-t ar ge t o rgani s m s . th e p o te ntial f o r eco log ica l ex p os ure is low s ince th e pro du c t i s in f u se d into a p o ly m e r pe ll e t w hi c h i s e ncl osed in T yve k 1i s ach e t w hi c h i s pl ace d in s ide a tra p d ev ic e furth e r limitin g th e p o tential ex p os ure. Th e re f o re, c o ntac t w ith a nd co nta min a ti o n of s urf a ce water , g ro und wa t e r o r so il i s hi g hl y unlik e l y fro m th e Page 5 o f7proposed pesticidal use of hexa n o ic acid. Further, fatty acids s uch as hexa no i c acid have been determi n ed to be biodegradable a nd are found exte n sive ly in the environment from natu ral sou rces making a ny unlikely in c r ementa l increase from th e pestic i dal use of no concern. T he Age ncy ha s also determined th at mo s t n o n-targe t insects , includin g h o n eybees, are not like ly to be exposed to hexa n oic acid at s ig nificant l e v e ls when u se d as a mo s qu ito lure s ince th ey are not likely to be a ttrac ted to the sce nt s targe ted at th e u ni qu e fe e din g pattern s of m osq uit oes . Bees in particu lar a re attrac t ed to fl o ral sce nt s while h exan o ic ac id h as a pun ge nt odor s imilar to swea t o r s tro n g cheese, which does not e nt ice bee s . Further, as described earlie r. incid enta l inh a la ti on exposures to n o n - target organi s m s are expected to be low g iven the low l eve ls being released from th e polymer pellets, th e ra pid dilution of these lo w l evels in ambien t outd oor a ir , a nd the ex ten s i ve presence of natura ll y occ urrin g h exano ic ac id in the env iro nm e nt. G ive n the lack of tox ic ity to non-ta rget organ is m s and the low pote ntia l for ex po s ure as a resu lt of the p ro po se d p es tic ida l u s es. the Agency doe s not anticipate ri s k of a dv e r se imp ac t s to non-target o rgani sms as a re s u lt of th e proposed u se patte rn. The Age nc y has evaluated th e potential r i sk of hexanoic acid ex p osure to endangered / threatened species and based on th e lac k of tox icit y to non-target organisms an d th e low potential for exposure described above, the use of BG- Sweet sce nt as a m osq uit o attractant trap w ill have "No E ff ec t " o n te rre s tri a l e nd a n ge r e d / t h r e ate n e d s p ec ies o r their de s ig n a ted c riti ca l habitats , as li sted b y th e U.S

. F is h a nd W il dlife Service (USF W S) and t h e National Oceanic and Atmospheric Admin is tration (NOAA). T h e u se pattern s (e n clo s ed trap) and re s ulti n g low potential ex p os ure to aq u a tic sys tem s a lso s how a finding of" No Eff e ct " t o e nd a n ge red/ thre atened a quati c s p ec ie s o r their designated critical habit a t s . In a dd it io n to l ow exposure potential res ult i ng fro m the proposed p es ti c id a l u se, the Agency a lso acknow l edges the natural occ urrence of hexanoic ac id in the env ironme nt a nd it s rapid decomposition. 

### 4.0 A lterna t iv es As w ith mo s t insect a ttr acta nt s, hexanoic acid i s ex pect e d to generally red u ce th e amount of conventiona l in sec t ic id es requi r ed fo r manag e m e nt and e rad icat io n of ta rge t ed insect popu la ti o n s s in ce no conventional p es tic ides are nece ssa ry to lure and trap the m osq uit oes. 

### 5 .0 Be n efit s Biopesticides are pesticides de ri ved f rom suc h n at ural materials as animals. plants. bacteria. and cer ta in min e ral s. Biochemicals, a class of biopes ti cides to w hich hexa n oic ac id b e lo n gs, ge n e ra ll y co mp a r e favorably to currently reg i s tere d conventio n a l a lte rn a ti ves f ro m a toxicity a nd e n viro nment a l s tandp o int b ecau se they arc natura ll y - occ urri n g substances (or s ub s tanc es s truc t urally- s imila r and fu n ctionall y ide nti cal to natura ll y - occu lT ing s ub s tanc es) with a h is tory of ex p os ure to hum a n s and th e e n v ironment d e m o n s tra t in g m inimal to xic ity a nd a nontox ic mod e of act ion to the target pest(s). B e n e fit s of biochemica l p es tic id es as compared to co n ven ti ona l pestic id es typically in c lud e lower toxicity profiles for humans and non-target organi sms, and fas ter degradation in th e e n vi ro nm ent. Add iti ona ll y . as o utlin e d above. hexanoic ac id has the potent ia l to reduce th e amou nt of more toxic co n ve nti ona l pe s ti c id e applications to manage or eradicate mosquitoes.

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### 5.0 Public Co mm e nts On August 25, 2015, EPA pub li shed a notic e of receipt of an ap plication in th e 

### Federal Regis ter to register an end us e product ( BG-Swee tscen t 9%) containing a proposed ne w active ingredient. Hex anoic Acid (80 FR. umber 164. pages 5 1 560

- 5161) and annou nced a pub Iic com m ent period of 30 days . o subs t a nti ve comment s ' e r e received. 

## 6.0 Proposed R eg ulatory Deci s ion The he xa n oic ac id database is co mpri sed o f s tudi es a nd inf o rm a ti o n that m ee t th e data requirement s for and s u pport the label ed use s of hexano ic acid. In cons ide rin g the assessed ri s k to hum an health and th e env ironme nt , th e EPA concludes that hexano ic ac id meets th e regulatory s tand ard under th e Federal In sec ticide, Fun gic ide. a nd R ode nti c id e Act (F IFRJ\ ). Th e refo r e . th e E PA i s proposing to grant the unconditional registration of th e he xa noic acid pes ti cide product s under F IFRA sec tion 3(c)(5). One end-use product. BG

- Sweet sce nt (8 .8 2% hexanoic ac id ). is being proposed l o r registration as a non-food use pesticide fo r use a s a lur e / a ttracta nt t arget in g m osq uito s . Th e product is formulated into p o rou s polymer pellet s which a re e ncl osed in Tyvek 19 sac he t s. The sac het s are placed in m os quito trap s whe r e the in sects a r e lur ed a nd di e . The human hea lth and eco log ic a l risk assessments su pp ort in g this d ecis ion as \veil as the draft labeling remain ava il ab le in th e r eg ulatory docket ( D ocket 10 E PA-HQ-OPP-20 1 5

- 0547).

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