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., Tmacolog1p · C 

Risk Assessment Branch V Nil ' ,-e:; 

Health Effects Division (7509P) 

Office of Pesticide Programs 

THROUGH: Michael 

Pete Savoia, 

Metzger, 

Chemist 

Branch 

a_

Chief :J:':t_ / U._f) ,/-'J ~~ ~ Risk Assessment Branch V Nil 

Health Effects Division (7509P) 

Office of Pesticide Programs 

. TO: Margaret Hathaway, Risk Manager Reviewer 

Kevin Costello, 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 13-0154, Pages 34-41, along with the 

corresponding HED response. 

Page 1 of3 
Toxicity/Hazard 

Comment 1: DAS 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 this 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 review process. 

Response: In order for the cancer classification to be reassessed, the registrant would need to 

request a cancer reassessment. The submission 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 handled through the 

Registration Division. 

Use Pattern 

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

Response: DAS clarification that uses on ornamental and/or shade trees, ornamental 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 

registration 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, attention 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 drinking 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 3 
Response: HED concurs with the DAS comment. At this time, based on the current toxicity 

database and exposure potential for non-occupational exposure, HED intends to evaluate the 

inhalation route of exposure for residential bystanders. 

Comment 9: 

• DAS states that air monitoring data generated by the California Air Resources Board 

(CARB) was performed between 2000 and 2001 and that California is a high use area for 

1,3-D. 

• A recently conducted air monitoring study is proposed to cover the airshed monitoring 

data required for the southwest climate zone. 

• DAS recommends that modeling of air concentrations in southeast, mid-atlantic, and 

pacific north-west climatic zones by using the SOFEA air dispersion modeling. 

Response: HED acknowledges the 1 ,3-D air concentration data generated by CARB. HED 

reaffirms the need to fulfill the data requirement. DAS cites a recently conducted air monitoring 

study, "Monitoring of Cis- and Trans-1,3-Dichloropropene in Air in 9 High 1,3-Dichloropropene 

Use Townships 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 airshed monitoring data. HED encourages DAS to identify the similarities 

between where the study was conducted and other locations in the U.S. where similar ambient 

conditions apply. The submission should include a formal plan detailing the use of SOFEA as an 

air dispersion model, include proposed input parameters for SOFEA modeling, and discuss the 

quality of the data sources. 

Page 3 of 3