UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHfNGTON , D .C
. 20460

OFFICE OF C HEMICAL SAFET Y AN D POLLUTIO N PREVE NT I ON MEMORANDUM DATE: May 21 , 2015 SUBJECT : Meto lach lor a nd S-Meto l ac hl o r . R es po n se to Co mment s on th e HED Human Hea lth Scop in g Doc um ent. PC Co de : I 08800 (S-Meto lac hl or); I 0880 I D P Barc o d e: 426906 (Me tolachlor)
De ci s ion No .: 50360 I R eg ist ration No s.: 100-815 , 11603-43 , 19713-539 , 17 Petit ion No .: NA Case No .: 0001 TXR N o.: NA MRID No .: NA

FROM:

THROUGH:

TO : Re g ulator y Acti o n : Reg is tration Rev iew R is k Assessment Type: NA CAS No.: 87392-12-9 , 512 18 -45-2 40 CFR: § 180.368

Jess i ca Kid we ll , Ri sk Assesso r

# ~**~** Th urs to n G. Morton , Chemis t

## ~Lfd"' 

# ----.. Ri s k Assess ment Branc h 4 H

ea lth E ffe ct s Divi s ion (7509 P)
C harl es S mith , Bran c h C hi ef 

# C-.**~** Risk Assess m e nt Branch 4 Health Effects Di visio n (7509 P)
S teve n S ny de rman , Chem ica l Review Mana ge r Ri s k Manageme nt and Impl em e ntati o n Bran ch 3 P

esti c id e R e-Eva luati o n Di v i s i on (7508P)


### Attached is HED 's R espo n se to Comment o n the human hea lth risk assessment sco ping document fo r m e tolachlor and S- metolachlor to s upport Re g i s tration Re v iew. 60063-



### The HED Meto lachlor an d S- metolachlor Ri s k Assess me nt t ea m ha s rec e i ve d co mments on the Re g i stratio n R eview Scoping Docume nt (E P A Docket ID: EPA -HQ- OPP-2014-0772-0003). Comments re levant to H E D ' s scopi n g document we r e provided by Synge nta. The co mm e nt s all fall within the che mi stry catego ry . Page 1 of 4

### Me to l ac hl o r a nd S -m e t o l ac h lo r . Hum a n H ea lth Sco p ing D oc um e nt in S u p p o rt of R eg i s t rati o n Rev i ew, Nov . 1 9, 201 4. PC Co d e 1088 0 0 (S- m e to lac hl or) ; 10880 1 (Meto l ac hl or) ; DP Ba rcode: 420468 (E P

A -H Q-OPP -20 14 -0772- 0003) 

### EPA S tateme n t Residue Chemistry, Pa ge 6 The label d irections for use are not all supported by res idue data. Di sc repa nc ie s were not e d fo r S- meto lachl o r on bulb vege tab les (s ho rt e r PHI than s upported by data) 

### Sy n ge nta Co mm e n t: S- meto lac hlor bulb vegetab le uses a re on l y o n Section 2 4 c labe l s registe red in multip le s tates. The approved direct ions fo r use allow for a s ingle maximum ap pli cation rate o f 1 .27 lb a i / A and a total maximum app li cation rate of 2
. 55 lb ai / A/c rop cycle wi th a pre-harvest i nt e r va l (PHI) of 60 days. These direct ion s fo r u se are s upport ed by MRID No. 46046503. In t hi s stud y, bu lb onions receive d two app lic ati ons of Du a l II MAGNUM (E P A Reg. No
. 100-818 ), the first applicati on ap pl ied at 590 g a i / A ( 1 .3 l b a i / A) as an early post app li cation followed by a second app l icatio n at 59 0 g a i / A ( 1. 3 lb ai/A) m ade 60 days prior t o th e harve st of dry on ion s. Based on this information , we believe that the re sidue data s upport s the label ed directio n s fo r use. 

### EPA Res p o n se : HED acknow ledges receipt of this infonnation and agree no add iti onal residue data are required fo r the registered bulb vegetab l e use.


### EPA Statement Res idu e Che mi s try, P age 6 Th e lab e l di r ections fo r u se ar e not all s upport e d b y r es idu e data. Discrepancies were noted for S- me tolachlor on ... cotton ( higher rat e) 

### Sy n ge nta Co mm e n t: S- me to lac hlor cotto n u ses are on multipl e product lab els, the directions for use of whic h are best repre se nted by the Dual Magnum (E PA R eg . No. l 00-816) Sect ion 3 lab e l. The approved directions fo r u se a ll ow fo r a s in g le m ax imum application r ate of 1. 6 lb ai/A and a t otal m ax imum application rate of2 .48 lb a i /A/year. Th e 1 .6 lb ai/A rate may o nl y be applied in the fa ll (Sept 1

- Dec l ), whic h is 5-6 month s prior to p lan tin g cotton. These directions for u se are s upporte d by MRID No. 491 86 50 

### I. In thi s study, cotton rec e ived two applications of Du al II MAGNUM ( 100 -818 ). Both applications we re applied at 1. 3 lb a i / A for a total ap pli cation rat e of 2 .6 lb a i / A. The firs t application was mad e at planting followed by e ither a broadcast s pray po s temergence over th e top ( 100 d ay PHI) o r post
- di rec ted sp ray at lay-by (80 day PHI ). This stud y s upp o rt s th e lab e led dir ect io n s for u se w ith the excep t ion of th e m ax imum fall use rate of 1.67 p t/A ( 1. 6 lb ai / A). This u se i s a fall u se and the lab el s tipulat es that ifsmetolachlor is used in the sp rin g, do not exceed the 2.6 pt/A (2.48 lb a i / A) maximum tota l use rate. We co ncur that the r es idu e s tud y do es not provide s p ecific data re presenting th e fa ll application at 1.6 lb ai/A. However , the l .33 lb a i /A preem e rge nc e app licatio n followed b y 1 .33 lb a i/ A posteme r gence ( in the s ame calen d ar year) i s a wo rst-case sce n ario compared to the 1.6 lb ai/A Fall app li cation (long PHI ) + 1. 00 lb a i / A preemergence or poste merge nc e (2.67 lb a i / A maximum). Therefore , we believe th at data from this stud y wo uld s upp ort this us e as the re s idue Page 2 of 4study r ep resents a wo r st case scenario
. The res idu e data does support the maximum total u se rat e of 2.48 lb ai / A/year. EPA Re s ponse : HED acknowledges receipt of this infom1ation and agree no additional residue data are required for the re giste red cotton use. EPA Statement Residu e C he mistry , Pag e 6 The label dir ec tion s for use are not all supported by re s idue data. Discrepancies were noted for S -metolachl or on ... soybeans (higher rate) Syngenta Co mment : S-metolachlor soybean uses are on multiple product labels , the directions for use of wh ich are best represented by th e Dual Magnum (EPA Reg. No. I 00-816) Section 3 label. Th e approved dir ect ions fo r use allow for a sing l e maximum application rat e of 1.9 lb ai / A and a total maximum application rate of 2.48 lb ai / A/year. These directions for use are supported by MRJD No. 47304702. In this stu d y soybeans received ei th er a s ingle soil surface spray at planting at 2.0 lb ailA , or two appl ication s consist ing of a preplant spray at 1 .2 lb ai/ A followed by a post-fo l iar broadcast spray at 1.3 lb a i / A for a total application rate of2.5 lb a i/ A. This study su pports both th e sing le maximum app li cation rat e of2.0 lb ai / A and the maximum total application rate of 2.48 lb ai/ A, w ith th e tota l app li cation rate o nl y being app li ed as a sp li t application. Data from another stu dy (MR I D No. 4392894 1) sup ports a 2.67 lb ai/ A sing le use rate of S-metolachlor as a p replant incorp o rated o r preemergence treatment on soils having an organ ic matter content between 6% and 20 %
. Based on this information , we believe that the two residue studies s upp ort the lab e led directions for use. EPA Re s pon se: HED acknow ledges receipt of this in formation and agree n o additio nal residu e data are required for the registered soybean use. EPA Statement Residue C h e mi stry , Pag e 6 T he label directions for use are not all su pported by residue data. Discrepanci es were noted for S-metolachlor on . .. tomato (h ig he r rate) Sy ngenta Co mment : S-metolachlor tomato uses are on multiple product lab e ls , th e directions for use of which are best represented by the Dual Magnum (E PA Reg. No. l 00

- 816) Section 3 label. The approved directions for use allow for a single m ax imum application rate of 1.9 lb a i / A. While the total maximum application rate is not specified, the lab e l implies a total maximum app li cation rate of 2.54 lb 

### ai lA/crop cycle. These directions for use are supported by MRID No. 44056 l 0 I. In this study, tomatoes were treated w ith metolachlor at a maximum rate of 3.0 lb ai / A with a 90 day pre-harvest interval ( PHI ). In a memorandum from EPA Dated Februar y 28 , 2002 (DP Barcode 8280 219) , the TRED co nclu sion stated that these data support the use of Smetolachlor on tomatoes at a maximum rate of I. 9 lb ai/ A , thus supporting the I. 9 lb ail A maximum s ingl e use rate. IR-4 Proj ec t PR 09668 (MR ID No
. 4804880 I ) further suppor t s th e use of S-metolachlor, wherein S-metolach lor was applied two times at a rate 1.3 7 lb ai/ A per appl ication , once at or around tran s plant followed by a banded/directed application to row middles 30 days prior to harvest. Page 3 of 4Th ese two st ud ies support two different use patte rns (different app li cation rates, m e thod s, and PHls) , which are expla in ed on the labe l. Ba sed on this information , we believe that the residue data supports the labeled directions for use. 

### EPA R es p on se: HED acknow ledges receipt of this information and agree no additional residue data are required for the registered tomato use.

Page 4 of 4