UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

MEMORANDUM 

Date: February 6, 2014 

SUBJECT: Imazamox: Tier I Review of Human Incidents 

PC Code: 129171 DPBarcode: 0417802 

Decision No.: 486514 

Petition No.: NA 

Risk Assessment Type: NA 

TXRNo.: NA 

MRIDNo.: NA 

Registration No.: NA 

Regulatory Action: NA 

Case No.: NA 

CAS No.: 1143 11-32-9 

40CFR: NA 

FROM: Elizabeth Evans, Environmental Protection Specialist 

Toxicology and Epidemiology Branch 

Health Effects Division (7509P) 

VocAp~ 

~~ and 

Shanna Recore, Industrial Hygienist 

Toxicology and Epidemiology Branch 

THROUGH: 

Health 

Dav~d Miller, 

Effect Divi

Acti~g 

sion 

Br~nch 

(7509P) 

Chie~ 1&/J t:;;~ f1~l'/l ~ Toxtcology and Eptdem10logy Braneli 

Health Effects Division (7509P) 

TO: Lata V enkateshwara, Risk Assessor 

Risk Assessment Branch I 

Health Effects Division (7509P) 

and 

Kelly Ballard, Chemical Review Manager 

Risk Management & Implementation Branch 1 

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 one incident involving imazamox reported to SENSOR-Pesticides. 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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Detailed Review 

I. 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 of the 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) is validated or otherwise 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, can 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 

Imazamox is the common name ofthe active ingredient ammonium salt ofimazamox (2-[4,5-

dihydro-4-methyl-4-( 1-methylethyl)-5-oxo-1 H-imidazo 1-2-yl ]-5-( methoxymethl )-3-

pyridinecarboxylic acid, trade name "Raptor Herbicide". Imazamox is applied to soybeans via 

ground or aerial application and may be applied postemergence. 

1 

For this evaluation, both the OPP Incident Data System (IDS) and the Centers for Disease 

Control and Prevention/National Institute for Occupational Safety and Health (CDC/NIOSH) 

Sentinel Event Notification System for Occupational Risk-Pesticides (SENSOR) databases were 

consulted for pesticide incident data on the active ingredient imazamox (pc code: 129171). The 

purpose of the database search is to identify potential patterns in the frequency and severity of 

the health effects attributed to imazamox exposure. lmazamox is not included in the AHS, and 

therefore this study 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 federal and state health and environmental agencies, and individual 

consumers. 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. 

1 EPA factsheet found online at: http:l/www.epa.gov/oppOOOO I /chem _search/reg_ actions/registration/fs _PC129171_22-May-97.pdf 

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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 of the 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 of exposure 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 January 15,2014, there were 0 incidents reported 

involving imazamox in the database. 

In Aggregate IDS, from January 1, 2009 to January 15,2014, there were 0 reported incident 

involving imazamox in the database. 

b. SENSOR-Pesticides 

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 State 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 pesticide 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 one single ai case involving imazamox (pc 

code 129171); no multiple ai cases were identified. This case occurred in Washington in 2009, 

the description states, 

"A 36 year old.female was tending her horses in their pasture on the morning of July II, 

2009, when an air blast spray application occurred in the field beside her. Wind was 

reported to be blowing in her direction at about 10 mph, and she describes seeing a 

cloud of mist and dust coming from the tractor onto her. She felt moisture on her skin and 

smelled the product. She reports experiencing immediate onset of neurological and 

respiratory symptoms, and GI discomfort, which resided about a day later. Onset of an 

additional G.J. symptom occurred 3 days after exposure. About I2 hours after exposure, 

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she describes experiencing dermal symptoms, like a bad sunburn on exposed skin, which 

resolved. She sought health care 9 days after exposure, due to a continuing sensation of 

numbness in her extremities. With her permission, DOH reported this case to WSDA. " 

It should be noted that this case was low in severity. The product implicated was Raptor 

herbicide (EPA reg.# 00024100379) 

c. Agricultural 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. If there are AHS findings relevant to a particular 

pesticide going through registration review, the Agency will ensure they are considered in the 

problem formulationlscoping phase of the process and, if appropriate, fully reviewed in the risk 

assessment phase of the process. The AI-IS includes information on use of 50 different pesticide 

active ingredients commonly used in agriculture. Imazamox is not included in the AHS, and 

therefore this study does not provide information for this report. 

IV. CONCLUSION 

There does not appear to be a concern at this time that would warrant further investigation, since 

there were was one incident involving imazamox reported to SENSOR-Pesticides. 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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