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



### Date: February 10, 2014 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

SUBJECT: 1,3-D. Response to Comments on the Human Health Assessment Scoping Document for Registration Review. PC Code: 029001 Decision No
. : 486078 Petition No.: NA Risk Assessment Type: NA TXRNo.:NA MRIDNo.:NA DP Barcode: D416853 Registration No.: NA Regulatory Action: Registration Review Case No.: NA CAS No .: 542-75-6 40 CFR: § 180.636
FROM: Ideliz Negron-Encarnacion, Ph.D., Chemist

# ~jft; L---**~atthew** Lloyd, CIH;

### lnd.ustriali~y~i**~ ~**  Lmda Taylor, Ph.D., Tmacolog1 p**·** 

# C Risk Assessment Branch V

### Nil ' ,-e:; Health Effects Division (7509P) Office of Pesticide Programs 

### T HROUGH : Michael Metzger, Branch Chief / 

# U._f)**~** Pete Savoia, Chemist 

# a_:J:':t_ ,/-'J

# ~~ Risk Assessment Branch V

### Nil Health Effects Division (7509P) Office of Pesticide Programs

. TO: Margaret Hathaway, Risk Manager Reviewer Kevin Coste ll o, Risk Manager Pesticide Re

- evaluation Division (7508P) Office of Pesticide Programs
Dow AgroScience (DAS) has submitted comments on the Health Effect's Division (HED) document titled 1 , 3-Dichloropropene
. Human Health Assessment Scoping Document in Support of Registration Review (09/05/13; D41 0 115). HED has presented DAS' s comments (from their submission dated 11/22/13, Dow AgroSciences' Comments to US. EPA's 1,3-Dichloropropene Registration Review Docket EP A-HQ

- OPP-20 1 3

- 0 1 54, Pages 34-41, along with the corresponding HED response.
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### Toxicity/Hazard Comment 1: D AS mentions an acute and subchronic neurotoxicity study waiver submitted to the agency. 

### Response: The information included in the waiver (MRID 49132401) was considered by the HASPOC in their deliberations
. Based on the weight-of-evidence approach and considering all the available hazard and exposure information the HASPOC concluded that the acute and subchronic neurotoxicity studies are not required for 1,3-D at thi s time. Comment 3: DAS disagrees with the classification of 1,3-D as a likely human carcinogen and the application of linear cancer risk analysis and believes that these should be re-evaluated as part of the registration rev iew process. 

### Response: In order for the cancer classification to be reassessed, the registrant would need to requ est a cancer reassessment. The submiss ion should include mode of action data for each tumor type and a weight-of-evidence assessment for consideration by the HED Cancer Assessment Review Committee. The corresponding PRIA action should be handl e d throu gh the Registration Division. 

### Use Pattern Comment 2: DAS clarifies information on the registered uses on ornamentals. 

### Response: DAS clarification that u ses on ornamental and/or shade trees, orname ntal herbaceous and non-flowering plants, and ornamental woody shrubs and vines are considered agricultural uses instead of non-agricultural uses is acknowledged. This comment will be considered in the re gistration review risk assessment. 

### Residue Chemistry I 

### Dietary Exposure Comment 5: DAS reiterates that a non-genotoxic mode of action, reduced cancer classification and risk assessment based on a threshold approach is supported by the available data. In addition, atten tio n is brought to the drinking water assessment of 1 ,3

- D. 

### Response: DAS comments on the cancer reclassification of 

### 1,3-D are addressed in the response to Comment 3. Evaluation of the drinkin g water exposure is to be addressed by the Environmental Fate and Effects Division (EFED). 

### Occupational and Residential Exposure Comment 6: DAS emphasizes that only inhalation exposure (to by

- standers) is applicable when considering residential exposure.

Page 2 of 3Response: HED concurs with the DAS comment. At this time, based on the curren t toxicity database and exposure potential for non-occupational exp osure , HED intends to evalua te the inh al ati on route of exposure for residential bystanders. Comment 9: • DAS states that air monitoring data generated by the Cal ifornia Air Resources B oard (CARB) was performed between 2000 and 200 1 and that Ca li fornia i s a high use area for 1 ,3-D
. • A recent ly conducted air monitoring study i s propo se d to cover the airshed monitoring data required for the so uthwest climate zon e. • DAS recommends that modeling of air concentrati o n s in so utheast , mid-atlantic, and pacific no rth-we st climatic zones by usin g the SOFEA air di spersion mode ling. Response: HED acknowled ges the 1 ,3- D air concentration data generated by CARB. HED reaffirms the need to fu lfill the data requirem ent. DAS c ites a recently conducted air monitoring study , "Moni to rin g of Cis

- and Trans-1 ,3 -Dichlorop ropene in A ir in 9 High 1,3

- Dichloropropene Use Towns hip s Merced County, California" in the submitted comments; HED encourages DAS to submit that study through official channels in order to determine whether the study can fill the data requirement for airsh e d monitoring data. HED encourages DAS to identify the similariti es between where the study was conducted and other location s i n the U.S. where si milar amb ient co nditions apply. Th e submi ssio n sh o uld includ e a forma l plan detai lin g the u se of SOFEA a s an air dispersion mode l , includ e proposed input parameters for SOFEA modeling , and di scu ss the quality of the data sources .

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