UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MEMORANDUM 

Date: January 31, 2013 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: Fenbuconazole. Occupational Exposw;e Assessment to Support Use of a New 

Formulation on Peppers. 

PC Code: 1290 II DP Barcode: 0404874 

Decision Nos.: 468478; 465307 Reg. Nos.: 62719-416; 62719-421 

Petition No.: 12F8304 Regulatory Action: Label Amendment 

Risk Assessment Type: ORE Case No.: 7012 

TXR No.: N/A CAS No.: 114369-43-6 

MRlD No.: N/A 40 CFR 180.480 

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Through: 

To: 

Michael Doherty, Ph.D., Senior Scientist 

Risk Assessment Branch II 

Health Effects Division (7509P) 

Erin Malone 

Fungicide Branch 

Registration Division (7505P) 

BACKGROUND: Dow AgroSciences LLC is proposing to bridge fenbuconazole residue data for 

peppers from a currently registered product to a new formulation. Residue data for Indar 75 

WSP (EPA Reg. No. 62719-421) were provided to bridge to the product Enable® 2F (EPA Reg. 

No. 62719-416). Indar® 75 WSP is a wettable powder formulation packed in water-soluble 

pouches containing 75.0% active ingredient (ai), while Enable 2F is a flowable concentrate 

containing 23.5% ai (2 lb ai/gal). Although the use pattern for peppers is the same on the 2 

labels, bridging residue data indicated that an increased tolerance for peppers would be needed. 

HED has taken into consideration the findings of the previous risk assessment for peppers and 

the differences in the 2 formulations, and has determined that a new occupational exposure and 

risk assessment is not needed to ensure adequate protection for occupational workers mixing, 

loading and applying the fungicide to peppers, or to those re-entering treated areas. 

COMPARISON OF USE PATTERN: lndar® 75 WSP is registered for use on pepper (including bell, 

chili, cooking, pimento, and sweet varieties) at single and seasonal maximum application rates of 

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0.188 and 0.75 lb ai/A, respectively. The label allows a maximum of 4 applications occurring 

at10-day intervals; however, the label prohibits more than 2 consecutive applications of 

fenbuconazole, in order to prevent development of resistance. The pre-harvest interval (PHI) is 7 

days after the last application. The registrant is proposing the same use pattern for Enable® 2F 

on pepper. 

The personal protective equipment (PPE) specified on the Indar® 75 WSP label includes baseline 

clothing (long sleeved shirt, long pants and shoes with socks), chemical resistant gloves, and 

chemical resistant head gear for overhead exposure. The same PPE recommendations are 

specified on the proposed label for Enable® 2F. Both labels have the same restricted-entry 

interval (REI) of 12 hours, which is based on the acute toxicity of the technical active ingredient. 

 

TOXICOLOGICAL DOSES AND ENDPOINTS USED FOR RISK ASSESSMENT: Details of toxicological 

doses and endpoints for fenbuconazole are available in the 2008 risk assessment (D. Dotson, 

D350321, 6/12/2008). Dermal risks were not assessed quantitatively due to the lack of systemic 

toxicity via the dermal route and the absence of developmental or reproductive effects that would 

not have been assessed in the dermal study. 

For inhalation assessment, HED previously selected the dose and endpoint from a chronic oral 

study, in the absence of a route-specific inhalation toxicity study. For the current action, a new 

occupational exposure assessment is not needed. In the 2008 assessment, the dose and endpoint 

(liver and thyroid effects) were selected from the chronic study in the rat; however, in the future 

HED will select the dose and endpoint from the 90-day rat study. Since the 90-day no-observedadverse-effects-level (NOAEL) and lowest-observed-adverse-effects-level (LOAEL) are higher 

than those seen in the chronic study, HED’s risk estimates for inhalation exposure will be lower 

than those estimated in the 2008 assessment. In conjunction with the risk assessment supporting 

the tolerance amendment for peppers, HED’s HASPOC determined that a subchronic inhalation 

toxicity study is not needed for fenbuconazole (TXR No. 0056540). 

In the absence of additional uncertainty factors to account for missing data, HED’s level of 

concern (LOC) for occupational risk assessment is a margin of exposure (MOE) of 100, based on 

10X interspecies and 10X intraspecies uncertainty factors. 

HED has classified fenbuconazole as “Group C Carcinogen” with a cancer potency factor (Q1

*

) 

of 3.59 x 10-3 (mg/kg/day)-1. 

RESIDENTIAL EXPOSURES: There are no registered residential uses for fenbuconazole including 

commercial/professional uses in residential areas. 

OCCUPATIONAL EXPOSURES: Long-term occupational exposure is not anticipated, either from 

dermal or inhalation routes. The conclusions regarding occupational handler and postapplication exposure and risk for Indar® 75 WSP and Enable® 2F are summarized below: 

Occupational Handler Assessments

Both product formulations were assessed for handler exposures, for similar scenarios. Indar® 75 

WSP was evaluated for use on pepper and other crops (S. Wang, D345898, 5/28/2008) and 
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Enable® 2F was assessed for use on cranberry, peanut, and other crops (M. Collantes, D28908, 

6/26/2006). Both assessments used the same single application rates (0.19 lb ai/A), equipment 

(ground and aerial foliar), timing (10 day interval), and number of applications (4) as are 

currently proposed for the label amendment for peppers. 

As stated previously, quantitative non-cancer dermal risk assessments were not needed due to the 

lack of toxicity via the dermal route. For Indar® 75 WSP on pepper, the estimated short-term 

non-cancer inhalation risk for handlers was an MOE greater than or equal to 9,100 assuming the 

use of baseline PPE; the MOEs were greater than 100 and are therefore not of concern. 

Combined dermal and inhalation cancer risk for occupational handlers was estimated to be at 

most 1.62 x 10-7. Given that the use patterns are similar, differences between risk estimates for 

the 2 formulations were driven by the unit exposures for the various handler scenarios. In 

previous assessments for Enable 2F, the non-cancer inhalation MOE for Enable® 2F was ≥ 2,600 

assuming baseline PPE, and the estimated combined dermal and inhalation cancer risk was at 

most 3.0 x 10-7. 

Occupational Post-Application Assessments

HED did not quantitatively assess non-cancer post-application dermal exposure and risk for 

Indar® 75 WSP or Enable® 2F due to the lack of systemic toxicity via the dermal route. Cancer 

risk for post-application exposure via the dermal route was estimated to be at most 9.9 x 10-8. 

Since the use pattern has not changed, and no new assessment is needed for the current action, 

HED did not conduct an updated post-application exposure assessment. A new assessment 

would address the following changes in the assumptions used: 1) increased body weight, from 

70 to 80 kg; 2) increased life expectancy, from 70 to 78 years; and 3) increased transfer 

coefficient, from 1,000 to 1,900 cm2/hour for high exposure activities. The use of these 

assumptions would increase estimated post-application cancer risk to approximately 1.4 x 10-7. 

OVERALL CONCLUSIONS: Both Indar® 75 WSP and Enable® 2F products were evaluated for 

similar occupational handler and post-application scenarios. Since the estimated handler MOEs 

for both formulations are greater than HED’s LOC of 100 (i.e., there are no risks of concern), a 

new occupational assessment is not needed in order to support the proposed amendment (i.e., 

adding pepper) to the Enable® 2F label. The cancer risk associated with post-application 

exposure increased to approximately 1.4 x 10-7

, with the increase being largely attributed to the 

increase in the transfer coefficient for high exposure activities.