UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

MEMORANDUM 

Date: January 22, 2013 

SUBJECT: Atrazine, Propazine and Simazine: Review of Human Incidents 

PC Code: 080803, 080808, 080807 

Decision No.: 472846 

Petition No.: NA 

Risk Assessment Type: NA 

TXRNo.:NA 

MRID No.: NA 

DP Barcode: 0407491 

Registration No.: NA 

Regulatory Action: NA 

Case No.: NA 

CAS No.: 1912-24-9, 139-40-2, 122-34-9 

40CFR: NA 

FROM: Shanna Recore, Industrial Hygienist 

Toxicology and Epidemiology Branch 

Health Effect Division (7509P) 

and 

Ver.Apr.08 

Elizabeth Evans, Environmental Protection Specialist -"'-) 

THROUGH: 

TO: 

Toxicology and Epidemiology Branch · · fJ ~~ 

Health Effect Division (7509P) 12 · r ~ ~~JYl David Miller, Acting Branch Chief r-j .iJh ~ Toxicology and Epidemiology Branch 

Health Effects Division (7509P) 

Seyed Tadayon, Risk Assessor 

Risk Assessment Branch V 

Health Effects Division (7509P) 

and 

Molly Clayton, Chemical Review Manager 

Risk Management & Implementation Branch III 

Pesticide Re-evaluation Division (7508P) 

Summary and Conclusions 

Based on the low frequency and severity of incident cases reported for atrazine, propazine and 

simazine in both the IDS and NIOSH SENSOR-Pesticides databases, there does not appear to be 

a concern at this time that would warrant further investigation. However, based on current AHS 

findings for atrazine, we intend to further evaluate follow-on studies from the AHS. In addition, 

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the Agency will continue to monitor the incident information and if a concern is triggered, 

additional analysis will be also be included at that time. 

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 

Atrazine, propazine and simazine are chlorinated triazine herbicides. Atrazine is currently 

registered for use against broadleaf and some grassy weeds. Atrazine is used on corn (field and 

sweet), guavas, macadamia nuts, sorghum, sugarcane, range grasses under USDA's 

Conservation Reserve Program (CRP), and wheat (where application is to wheat stubble on 

fallow land following wheat harvests; wheat is not the target crop). Atrazine is also used in 

conifer forests, on Christmas tree farms and on sod farms, golf courses and residential lawns. 

Propazine is a systemic herbicide that is usually applied to the soil, absorbed through leaves and 

roots, and acts by inhibiting photosynthesis within the targeted plant. It is used as a selective 

herbicide to control most annual grasses and broadleaf weeds before the weeds emerge or after 

removal of weed growth. Propazine is registered for use on container-grown ornamentals in 

greenhouses. Simazine is used pre-emergence for control of broad-leaved and grassy weeks on a 

variety of deep-rooted crops such as artichokes, asparagus, berry crops, broad beans, and citrus 

and on non-crop areas such as farm ponds and fish hatcheries. 

For this evaluation, both 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 ingredients atrazine, propazine and simazine 

(PC Codes 080803, 080808, and 080807). The purpose of the database search is to identify 

potential patterns in the frequency and severity of the health effects attributed to atrazine, 

propazine or simazine exposure. 

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The Agricultural Health Study (AHS) is a high quality, prospective epidemiology study 

evaluating the link between pesticide use and various health outcomes including cancer. 

Atrazine is included in the AHS and provides 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. 

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 specific. 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 

pesticide 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. 

The Main and Aggregate IDS findings for atrazine, propazine, and simazine are presented below:

Atrazine:

For the Main IDS, from January 1, 2007 to December 11, 2012, there were 18 incidents reported 

for single chemical only in the database. Two of these incidents were classified as major 

severity and are described further in Table 1. Sixteen incidents were classified as moderate 

severity. There were 23 additional incidents reported involving more than one chemical. 

Overall, there are few incidents involving atrazine reported to IDS. 

In Aggregate IDS, from January 1, 2007 to December 11, 2012, there were 102 reported

incidents involving atrazine. These incidents were classified as minor severity.

Propazine:

For the Main IDS, from January 1, 2007 to December 11, 2012, there were no incidents 

involving propazine in the database. 

In Aggregate IDS, from January 1, 2007 to December 11, 2012, there were no reported incidents

involving propazine in the database. 
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Simazine:

For the Main IDS, from January 1, 2007 to December 11, 2012, there were 3 incidents reported 

for single chemical only in the database. One of these incidents was classified as major severity 

and is described further in Table 1. Two incidents were classified as moderate severity. There 

was 1 additional incident reported involving more than one chemical. Overall, there are few 

incidents involving simazine reported to IDS. 

In Aggregate IDS, from January 1, 2007 to December 11, 2012, there were 3 reported incidents

involving simazine. These incidents were classified as minor severity.

b. NIOSH SENSOR

The NIOSH SENSOR database covers 11 states from 1998-2009, 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 focuses on occupational 

pesticide incidents, and is of particular value in providing that information. A state SENSOR 

contact specialist attempts to follow-up with cases and obtains medical records to verify 

symptoms, circumstances surrounding the exposure, severity, and outcome. Using standardized 

protocol and case definitions derived from poison center reporting, SENSOR coordinators at 

State Departments of Health enter the incident interview description provided by the case, 

medical report, physician and patient into the SENSOR data system. The SENSOR data system 

is accessible to participating states and EPA.

Atrazine:

In NIOSH SENSOR from 1999 to 2009 there are 115 cases for atrazine stemming from 61 

atropine exposure events. Atrazine was the single active ingredient implicated in 35 cases. Most

(101) cases were classified as low severity, 13 cases were classified as moderate severity and 1 

case was classified as high severity. Respiratory symptoms were the most frequently reported 

health effect (n=61) followed by symptoms related to the nervous system (n=57) (Table 2). 

Twenty four cases were exposed at their place of work. Seventy nine cases (69%) were exposed 

to pesticides via drift. 

Table 2. SENSOR-Pesticides 1998-

2009: Reported Health Effects for 

Atrazine Cases* 

Dermal 38

Ocular 46

Respiratory 61

Gastrointestinal 37

Renal 0

Nervous System 57

Cardiovascular 5

Misc. 15
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* Cases may report multiple health 

effects

Activity at the time of exposure

The activity at the time of exposure included both occupational and non-occupational activities 

which break down as follows:

44 cases were conducting routine nonoccupational outdoor living activities at the time of 

exposure; 4 of these were moderate in severity and 40 were low in severity. Of these 44 

cases, 36 were attributable to drift. 

30 cases were conducting routine nonoccupational indoor living activities; one of these 

cases was high in severity, four were moderate in severity and 25 were low in severity. 

Of these 30 cases, 26 were attributable to drift.

17 cases were exposed while applying the pesticide, six of these were occupational and 

the majority of the remaining cases involved residents making lawn applications. One 

case was moderate in severity and 16 were low in severity.

15 cases (all occupational) were conducting routine work, including field work; two of 

these 15 cases were moderate in severity and 13 were low in severity. This group 

included one event where 11 field workers were exposed to drift from an aerial 

application on an adjacent field; event details are provided below.

Multiple case events

There are several multiple case events involving atrazine. Events involving ten or more cases are 

summarized here. In Florida in 2004, 18 symptomatic cases were reported after a pest control 

operator applied multiple pesticides, including atrazine, at the wrong location. One of these 

cases was moderate in severity and 17 were low in severity. Another event which occurred in 

Louisiana in 2002, 10 symptomatic cases were reported after being exposed to aerial drift from a 

multiple pesticide herbicide application made to a sugarcane field adjacent to the residence. 

Cases reported a variety of symptoms including coughing, sneezing, nausea, vomiting, diarrhea, 

eye and skin irritation, difficulty breathing, and dizziness. All 10 cases were low in severity. 

Finally, in Washington State in 2005, 11 greenhouse workers were made ill after being exposed 

to drift from an herbicide application. One of these cases was moderate in severity and 10 were 

low in severity.

Propazine:

A query of SENSOR-Pesticides 1998-2009 finds no reported cases for propazine.

Simazine:

A query of SENSOR-Pesticides 1998-2009 finds 20 reported cases for simazine stemming from 

19 simazine exposure events. Five cases involved simazine as the single active ingredient. 

Seventeen cases were work-related. There was one case classified as high severity, four cases 

classified as moderate severity and 15 cases classified as low severity. Eight cases were exposed 

while applying a pesticide. The effects reported include respiratory, ocular, nervous system, 

gastrointestinal, cardiovascular, and dermal (Table 3).
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Table #3. SENSOR-Pesticides 1998-

2009: Reported Health Effects for 

Simazine Cases* 

Dermal 8

Ocular 10

Respiratory 8

Gastrointestinal 3

Renal 0

Nervous System 11

Cardiovascular 1

Misc. 2

* Cases may report multiple health 

effects

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 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.

Since the time of the last evaluation of epidemiological literature pertaining to atrazine (Sept. 

2010 non-cancer effects, and July 2011 cancer effects) there have been four new studies 

published in the peer review literature that merit further consideration in the registration 

review/risk assessment process. Each study extends work included in the previous evaluation by 

EPA, specifically adverse birth outcomes, and menstrual cycle characteristics in association with 

environmental exposure to atrazine. Craigin et al. (2011) performed a cross-sectional analysis of 

atrazine exposure and menstrual cycle characteristics among a cohort of women residing in 

Illinois (high atrazine use area) and Vermont (low atrazine use area). Authors measured atrazine 

exposure using three different metrics of individual-level exposure, requested participants 

compile a menstrual cycle diary, and measured urinary concentration of steroid hormone levels. 

Overall, this work supports and extends the previously published studies by Farr et al. (2004) 

using Agricultural Health Study data. Craigin et al. (2012) reported associations with menstrual 

cycle irregularities, but not cycle length, absence of cycle, or intermittent bleeding. Authors also 

showed a link with certain hormone levels and atrazine exposure including estradiol metabolites 

during the LH surge of the cycle. A full evaluation of this study will take place during the 

preparation of the risk assessment.

Additionally, two study groups evaluated aggregate level atrazine exposure (proximity of 

maternal residence to agricultural area and/or drinking water monitoring site) and pre-term birth 
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and an adverse birth outcome (choanal atresia and stenosis), respectively (Rinsky et al. 2012 and 

Agopian et al. 2012). Both study groups reported statistically significant positive association 

with measures of atrazine exposure, and the use of aggregate level exposure measures is noted. 

Chevrier et al. (2011) evaluated birth characteristics in association with atrazine exposure in a 

prospective birth cohort located in Brittany, France. Authors performed individual-level 

exposure assessment (urinary concentration of atrazine) taken mid-point in pregnancy. 

Researchers reported an approximate 50% increase in fetal growth restriction and small head 

circumference among the cohort participants, but no association with major birth defects was 

reported. 

EPA will evaluate these new additions to the observational data base regarding adverse health 

effects as a result of environmental exposure to atrazine, and integrate these findings with the 

other studies already reviewed and presented to the public at the FIFRA Science Advisory Panel 

in September 2010.

Propazine and simazine are not included in the AHS.

IV. CONCLUSION

Based on the low frequency and severity of incident cases reported for atrazine, propazine and 

simazine to both IDS and NIOSH SENSOR-Pesticides, there does not appear to be a concern at 

this time that would warrant further investigation. However, based on current AHS findings for 

atrazine we intend to further evaluate follow-on studies from the AHS. In addition, the Agency 

will continue to monitor the incident information and if a concern is triggered, additional 

analysis will be also be included at that time. 

Citations:

1: Agopian AJ, Cai Y, Langlois PH, Canfield MA, Lupo PJ. Maternal Residential

Atrazine Exposure and Risk for Choanal Atresia and Stenosis in Offspring. J

Pediatr. 2012 Oct 1. doi:pii: S0022-3476(12)00929-8. 10.1016/j.jpeds.2012.08.012.

[Epub ahead of print] PubMed PMID: 23036484.

2: Rinsky JL, Hopenhayn C, Golla V, Browning S, Bush HM. Atrazine exposure in

public drinking water and preterm birth. Public Health Rep. 2012

Jan-Feb;127(1):72-80. PubMed PMID: 22298924; PubMed Central PMCID: PMC3234399.

3: Cragin LA, Kesner JS, Bachand AM, Barr DB, Meadows JW, Krieg EF, Reif JS.

Menstrual cycle characteristics and reproductive hormone levels in women exposed 

to atrazine in drinking water. Environ Res. 2011 Nov;111(8):1293-301. doi:

10.1016/j.envres.2011.09.009. Epub 2011 Oct 13. PubMed PMID: 22000761.

4: Chevrier C, Limon G, Monfort C, Rouget F, Garlantézec R, Petit C, Durand G,

Cordier S. Urinary biomarkers of prenatal atrazine exposure and adverse birth

outcomes in the PELAGIE birth cohort. Environ Health Perspect. 2011

Jul;119(7):1034-41. doi: 10.1289/ehp.1002775. Epub 2011 Mar 2. PubMed PMID:
Page 8 of 9

21367690; PubMed Central PMCID: PMC3222984.
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Table 1. Main IDS Major Incidents 

Human Incident Chemical: Atrazine PC Code: 080803

Incident 

Package 

Report

Incident 

Date Location

Reg 

Number Product Name

Exposure 

Severity 

Codes Incident Description

018825 -

00038 7/3/2007 LA NA ATRAZINE HB

A 66 year old male applied the product on top of 

gasoline to treat his property. It caught on fire and he 

inhaled the fumes. He was takes to a local health care 

facility and treated for shortness of breath, shakiness, 

and headache. He also had an EKG and CT and treated 

with steroids which improved his breathing. He was 

transferred to a hospital and eventually an ICU.

019218 -

00015 1/1/2007 FL 000538-00229

SCOTTS BONUS 

S 

WINTERGUARD 

SOUTHERN 

WEED AND 

FEED 

FERTILIZER 

PLUS HERB

HB

An adult female reports that her husband and neighbor 

have used the product for years. She suspects that she 

and her husband are getting poisoned by the product 

because of a crack in her water line. She has been 

experiencing dry mouth, food not tasting right, and 

Paresthesia of the lips and hands. She has been to the 

ER multiple times over the last year with these ailments. 

Her husband has experienced mental sluggishness, 

kidney failure, and throat cancer. 

Human Incident Chemical: Simazine PC Code: 080807

019115 -

00001

10/30/2007 SILVER 

SPRINGS, 

TX

034704-

00687

SIMAZINE 4L 

FLOWABLE 

HERBICIDE

HB

An 8 year old male played soccer on a field that had 

been treated with the product a week prior. He 

experienced respiratory arrest and was hospitalized 

overnight. He had an appointment to follow-up with 

Children's Medical Center.

*HB-Human Major (if the person alleged or exhibited symptoms which may have been life-threatening, or resulted in adverse reproductive effects or in residual disability)