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

Date: 3/5/13 

### MEMORANDUM OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### SUBJECT: Ancymidol. Regi st ration Review Preliminary Risk Assessment. 

### PC Code: 1 08601 

### DP Barcode: D408396 

### Decision No.: 474083 

### Registration No.: 10163 -277 

### Petition No.: NA 

### Regulatory Action: Registration Review 

### Risk Assessment Type: Single Chemical 

### Case No.: 3017-1 Aggregate 

### TXRNo
. : NA 

### CAS No.: 12771-68-5 

### MRIDNo.: NA 40 

### CFR: NA 

### FROM: DonnaS. Davis, Risk

# Assessor**CJ:;[Jtt~~l-(:)_** Health Effects Division (7509P) 

### THROUGH: Michael Metzger, Chief

# ~~ 

# /) (} f

# ~ Ri sk Assessment Branch VII

## ~ 

# !\ Health Effects Division (7509 

### TO: Christina Scheltema, Risk Manager T racy Perry, Team Leader Patricia Parrott, Chief Risk Management and Imp lementation Branch III Pesticide Re-E valuation Division (7508P)

Page 1 of2Ancymido l Registration Review Preliminary Risk Assessment Ancymidol is a plant growth re gulato r. Ancymidol is a Type liB gibberellic acid inhibitor and is used to prevent elongation, or "legginess" in ornamenta l plants. The Biological and Analysis Division (BEAD) has indicated that no more than 20 lbs total of ancymidol are u sed per year in the U.S
. (BEAD Chemical Profile for Registration Review, Rafael Prieto, 11/19/1 0). Ancymidol i s formulated as a so lubl e co ncentrate or liquid currently regist ered for uses in n urs eries, greenho uses , shadehouses and interiorscapes. Ancymido l appears to be predominantly applied to containerized bedding ornamental plant plugs in greenhouse propagation settings (i.e., indoors under glass). There are a lso some drench type applications in greenhouses an d small sc al e treatments of ornamental seeds. Th ere are no agricultural or reside nti al uses of this active ingredient. Given the use pattern, exposure is limited to workers applying ancymidol. Workers are expected to be exposed only throu gh the dermal and inhalation routes of exposure. A 21-day guideline dermal toxicity study conducted in the rabbit showed no dermal irritation or system ic toxicity after repeated exposure up to the limit dose of 1000 mg/kg/day. Therefore ; the Agency concludes that ancymido l does not pose a dermal risk. Expo sures via the inhalati on route are expected to b e acute in nature and exceptionally low given the registered application r ates and the lo w total poundage applied in the U.S. Ancymido l has low acute inhalation toxicity. In light of th e extremely low application rates, the Agency has consi dered the available hazard information and finds nothing in the database or in the literatur e that would suggest that this active ingredient is s ufficiently potent to rais e a concern at such low expos ure levels. Based on the limited use pattern, the minimal inhalation exposure , and the lack of evidence that ancymidol displays significant toxicity by the inhalation route; the Agency does not believe that this active ingredient poses an inhalation risk. No additional exposure or hazard information are required to support the registration review of ancymidol. Quantitative risk assessments are not required for this active ingredient and the Agency does not believe that the current re gistered uses of ancymidol pose a human health risk of concern.

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