UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

MEMORANDUM 

Da te: August 6, 201 5 

SUBJECT: Diuron: Tier I (Scoping) Review of Human Incidents/Epidemiology 

PC Code: 03 5505 DP Barcoclc: 0 428534 

Decision No.: 496087 

Pet ition No.: NA 

Ris k Assessment Type: A 

TXR No.: J\ 

lRID No.: A 

Registration No.: NA 

Regulatory Action: NA 

Case No.: NA 

CAS No.: 330-54-1 

40 CFR: . A 

Ver.Apr.08 

FROM: Shanna Recore, Industrial Hygienist t _ _, /"\. ,,., 

Toxicolo

Health Eff

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Branch ~ ~ 

and 

Elizabeth Evans, Environmental Protection Specialist 

Toxicology and Epidemiology Branch 

Health Effects Division (7509P) a 

/ I l(l t;6 ~,;101S THROUGH: David Mill er, Acting Branch Chief v /j//J 

TO: 

Toxicology and Epidemiology Branch 

Health Effects Division (7509P) 

Karlyn Middl eton, Risk Assessor 

Risk Assessment Branch II 

Health Effects Division (7509P) 

and 

Katherine StCla ir, Chemical Review Manager 

Risk Management & Implementation Branch 2 

Pesticide Re-evaluation Division (7508P) 

Summary and Conclusio ns 

Based o n the low frequency and low severity of incident cases reported for diuron in IDS, 

SENSOR-Pesticides, and N PIC there does not appear to be a concern at this time that would 

warrant further investigation. The Agency will continue to monitor the incident informatio n and 

if a concern is triggered, additio nal 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 summari es 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 " incidenC) arc 

largely self-reported and therefore, generally speaking, neither exposure to a pesticide or 

repo11ed symptom (or the connection between the two) is validated or otherwise confirmed. 

Typica ll y, 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 speci fie sub-groups like pesticide applicators. 

II. BACKGROUND 

Diuron is a pre- and post-emergent herbicide that controls a wide variety of annual and perennial 

broad leafed and grassy weeds on both crop and non-crop sites. The mechanism of herbicidal 

action is the inhibition of photosynthesis. Products containing diuron are intended for both 

occupational and residential uses. Occupational uses include agricultural food and non-food 

crops; ornamental trees, flowers, and shrubs; paints and coatings; ornamental fish and catfish 

production; rights-of-way and industrial sites. Residential uses include ponds, aquariums, and 

paints. 

For this evaluation, both the OPP Incident Data System (IDS), 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), and the National 

Pesticide Information Center (NPIC) databases were consulted for pesticide incident data on the 

active ingredient diuron (pc code: 035505). The purpose of the database search is to identify 

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

exposure. Diuron is not included in the /\HS, and therefore this study does not provide 

information for this report. 

III. RES UL TS/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 

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 

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submitted to the IDS represent anecdotal reports or a llegatio ns only, unless otherw ise 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 speci fi cs. 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 informatio n 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. 

Por the Main IDS, from January 1, 2009 to August 12, 20 14, there were 3 incidents reported 

involving diuron. They were classified as moderate severity. 

In Aggregate IDS, from January 1, 2009 to August 12, 20 14, there were 49 incidents reported 

involving diuron. Thirty six of these incidents were classifi ed as minor severity. Thirteen 

incidents were classified having no or unknown effects. Overall, there are few incidents 

involving diuron reported to lDS . 

b. SENSOR-Pesticides 

The SENSOR-Pesticides database covers 11 states from 1998-20 10, a lthough 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 cla ims when reported by physicians, reports from State Departments of 

Agri culture, and physici an 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 N TOSH a1mually to be aggregated. 

A query of SENSOR-Pesticides from 1998-20 I 0 identifies 92 cases involving diuron (pc code 

035505) stemming from 49 events. Of these 92 cases, nine cases stemming from five events 

involve a single acti ve ingredient and were analyzed for this memo. All nine cases were low in 

severity. Two cases were occupational and seven cases were non-occupational. Five of the nonoccupational cases (all five cases resulted from one event) occurred after one Right-of-way 

application was made to a railroad track in Oregon in 2000. These five cases each individually 

crossed railroad tracks that had been treated with Dircx 80 OF, EPA reg # 181 2-362. Another 

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non-occupational case occurred when an individual swam in a pond that had been treated with 

diuron, which is an illegal use of the pesticide. No further information was provided regarding 

this case. The seventh non-occupational case involved a child near his fathe r when applying the 

pesticide and the dust got into the child's eye. The two occupational cases involved pesticide 

applications, one of which was a Right-of-Way applicator, the second occupational case did not 

include a case description. In sum, a total of six out of the nine single ai cases were exposed as a 

result of Right-of-way applications. The leading health system effected involved the nervous 

system; the chief symptom reported among cases headache. Table 2 presents a summary of 

health effects reported for the nine single active ingredient cases. 

Table 2. SENSOR-Pesticides 1998-2009: Reported 

Health Effects for Cases (N=9) 

Health Effect # of Times Reported 

Denna I 4 

Ocular 5 

Respiratory 4 

Gastrointestinal 6 

Renal 0 

Nervous System 7 

Cardiovascular 0 

"'Cases may report multiple health effects 

c. National Pesticide Information Center (NPIC) 

The National Pesti cide Information Center or NPIC is a cooperative effort between Oregon State 

Uni versity and EPA which is funded by EPA to serve as a source of objective, science-based 

pesticide information and respond to inquiries from the public and to incidents. NPIC functions 

nationally during weekday business hours through a toll-free telephone number in addition to the 

internet (www.npic.orst.edu) and email. Similar to Poison Control Centers, NPIC's primary 

purpose is not to collect incident data, but rather to provide information to inquirers on a wide 

range of pesticide topics, and direct callers for pesticide incident investigation and emergency 

treatment. Nevertheless NPIC does collect information about incidents (approximately 4000 

incidents per year) from inquirers and records that information in a database. NPIC is a source 

of national incident information but generally receives fewer reports than IDS. Regardless, if a 

high frequency is observed in ID S, NPIC provides an additional source of information to see 

whether there is evidence of consistency across national data sets or possibly duplication and 

additional infonn ation about the same incident(s). 

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From 2009 to June 30, 2014, 6 incidents were reported to NP.IC involving diuron. NPIC 

estimates a certainty index as to whether an incident (including reported symptoms) was either 

definitely, probably, possibly, or unlikely to have been caused by the reported exposure to a 

pesticide, or whether the incident was unrelated to pesticides or if the incident was unclassifiable. 

Of the 6 reported incidents, 3 were reported as symptomatic and classified as probably related to 

the diuron exposure, 2 cases were classified as unlikely and I case was unclassifiable. The three 

probable incidents were classifi ed as minor severity. 

d. Agricultural Health Study (AHS) 

The AHS is a high quality, prospective epidemiology study evaluating the link between pesticide 

use and vari ous health outcomes including cancer. The Al-IS 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 AI-IS includes information on use of 80 different pesticide 

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

therefore this study does not provide information for this report. 

IV. CONCLUSION 

Based on the low frequency and low severity of incident cases reported for diuron in IDS, 

SENSOR-Pesticides, and NPJC there does not appear to be a concern at this time that would 

warrant further investigation. 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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