UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### MEMORANDUM Date: May 15, 2014 SUBJECT: Imazaquin: Tier I Review of Human Incidents PC Code: 128848 Decision No.: 488888 Petition No.: NA Risk Assessment Type: NA TXRNo.: NA MRIDNo.:NA DP Barcode: 0420257 Registration No.: NA Regulatory Action: NA Case No.: NA CAS No.: 81335-37-7 40CFR: NA Ver
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### FROM: Elizabeth Evans, Environmental Protection Specialist · t"":' _;:, 

### Toxicology and Epidemiology Branch 

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# A**~** Health Effects Division (7509P) 

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. and Shanna Recore, Industrial Hygienist Toxicology and Epidemiology Branch Health Effect Division (7509P)
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# J A/t,_ A-5"JJ611VI'( THROUGH : David Miller, Acting Branch Chief

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### Toxicology and Epidemiology Branch Health Effects Division (7509P) TO : Danette Drew, Risk Assessor Risk Assessment Branch V Health Effects Division (7509P) and W. Livingsto n, Chemical Review Manager Risk Management & 

### Implementation Branch 4 Pesticide Re-evaluation Division (7508P) Summary and Conclusions There does not appear to be a concern at this time that would warrant further investigation , since there was a low frequency of incidents invo lving imazaquin reported to IDS and SENSORPage 1 

### of 4Pestic ides. The Agency will continue to monitor the incident information and if a concern is triggered, additional analys i s will be included in the risk assessment. Detailed Review 

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. ACTION REQUESTED This review is intended to fulfill our requirement to docket summaries of incident data that were reported to the Agency, as well as to ensure human incident data and the Agricultural Health Study (AHS) are part ofthe problem formulation phase of registration review
. Reports of adverse health effects allegedly due to a specific pesticide exposure (i.e., an " incident") are largely self-reported and therefore, generally speaking, neither exposure to a pesticide or reported symptom (or the connection between the two) i s validated or ot herwi se confirmed. Typically, causation cannot be determined based on incident data. However, incident information can be an important source of feedback to the Agency: incidents of severe outcome, or a suggested pattern or trend among less severe incidents, ca n signal the Agency to further investigate a particular chemical or product. Observational epidemiology studies relate the risk of disease, 

### e.g., cancer, and exposure to an agent such as a pesticide product in the general population or specific sub

-groups like pesticide applicators. 

### II. BACKGROUND Imazaquin is an imidazolinone herbicide which controls weeds by inhibiting the synthesis of specific amino acids (valine, leucine & isoleucine) necessary for plant growth. It is registered as a preplant, preemergence and early postemergence herbicide for use on soybeans, primarily across the central Midwest from Kentucky to Illinois and across the mid-South in Arkansas, Louisiana and M i ssissippi. It i s also reg i stered fo r pre- and postemergence weed control on ornamentals and warm season turfgrass in both residential and non-residential settings. The turf and ornamental uses are concentrated across the southern U.S. because of imazaquin's lack of selectivity on cool season grasses. For this evaluation, both the OPP Incident D ata System (ID S) and the Centers for Disease Control and Prevention/National Institute for Occupational Safety and He alth (CD C/NIO SH) Sentinel Event Notification System for Occupational Risk-Pesticides (SENSOR) databases were consulted for pesticide incident data on the active ingredient imazaquin (pc code : 128848). The purpose ofthe database search is to identify potential patterns in the frequency and severity of the health effects attributed to imazaquin exposure. Imazaquin is not included in the AH S, and therefore this s tu dy does not provide information for this report. 

### III. RESULTS/DISCUSSION
a. IDS (Incident Data System) OPP's IDS includes reports of alleged human health incidents from various sources, including mandatory Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) Section 6(a)(2) reports from registrants, other fede ral and state health and environmental agencies, and individual Page 2 of 4consumers. Since 1992, OPP has compiled these reports in IDS. IDS contains reports from across the U.S. and most incidents have all relevant product information recorded. Reports submitted to the IDS represent anecdotal reports or allegations only, unless otherwise stated in the report . IDS records incidents in one of two modules: Main IDS and Aggregate IDS:
o Main IDS contains incidents resulting in higher severity outcomes and provides more detail with regard to case specifics. This system stores incident data for death, major and moderate incidents, and it includes information about the location, date and nature ofthe incident. Main IDS incidents involving only one active ingredient (as opposed to pesticide products with multiple active ingredients) are considered to provide more certain information about the potential effects ofexposure from the pesticide.
o Aggregate IDS contains incidents resulting in less severe human incidents (minor, unknown, or no effects outcomes). These are reported by registrants only as counts in what are aggregate summaries. For the Main IDS , from January 1, 2009 to March 5, 2014, there were 0 incidents reported involving imazaquin in the database. In Aggregate IDS, from January 1, 2009 to March 5 , 2014, there was 1 incident reported involving imazaquin in the database. This incident was classified as minor severity. 

### b. SENSOR-Pest icides The SENSOR-Pesticides database covers 11 states from 1998-2010, although reporting varies from state to state. Cases of pesticide-related illnesses are ascertained from a variety of sources, including: reports from local Poison Control Centers, state Department of Labor workers' compensation claims when reported by physicians , reports from Sta te Departments of Agriculture, and physician reports to state Departments of Health. Although both occupational and non-occupational incidents are included in the database, SENSOR-Pesticides focuses on occupational pes ticide incidents, and is of particular value in providing that information. The state coordinator at each of the 11 respective state Departments of Health conducts case followup activities such as obtaining medical records to verify symptoms and severity. Using standardized protocol and case definitions derived from poison center reporting, the state SENSOR-Pesticide coordinator enters the incident information into the state-based system which is sent to NIOSH annually to be aggregated. A query of SENSOR-Pesticides 1998-2010 identifies 0 cases involving imazaquin (pc code: 128848).


### c . Agricultura l Health Study (AHS) The AHS is a high quality, prospective epidemiology study evaluating the link between pesticide use and various health outcomes including cancer. The AHS includes private and commercial pesticide applicators and their spouses. Ifthere are AHS findings relevant to a particular Page 3 of 4pesticide going through registration review, the Agency will ensure they are considered in the problem formulation/scoping phase of the process and, if appropriate, fully reviewed in the risk assessment phase of the process . The AHS includes information on use of 50 different pesticide active ingredients commonly used in agriculture. Imazaquin is not included in the AHS, and therefore this study does not provide inf ormation for this report. 

### IV. CONCLUSION There does not appear to be a concern at this time that would warrant further investigation, since there was a low frequency of incidents involving imazaquin reported to IDS and SENSORPesticides. The Agency will continue to monitor the incident information and if a concern is triggered, additional analysis will be included in the risk assessment.

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