UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

MEMORANDUM

Date: May 25, 2011

SUBJECT: Metsulfuron: Review of Human Incidents

PC Code: 122010

Decision No.: 448313

Petition No.: NA

Risk Assessment Type: NA

TXR No.: NA

MRID No.: NA

 

 

FROM: Khin Swe Oo, Environmental Health Scientist

Toxicology and Epidemiology

Health Effect Division (7509P)

THROUGH: David Miller, Acting 

Toxicology and Epidemiology

Health Effects Division (7509P)

TO: Charles W. Smith

Risk Assessment Branch

Health Effects Division 

and

Jill Bloom, Chemical Review Manager

Risk Management &

Pesticide Re-evaluation Division (7508P)

I. CONCLUSION

Based on the low frequency and severity of incident cases, there does not appear to be a concern 

at this time that would warrant further investigation. The Agency will 

incident information and if a concern is triggered, additional analysis will be included in the risk 

assessment.

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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND

POLLUTION PREVENTION

Review of Human Incidents

DP Barcode: D389637

Registration No.: NA

Regulatory Action: NA

Case No.: NA

CAS No.: 74223-64-6

40 CFR: NA

Khin Swe Oo, Environmental Health Scientist

Toxicology and Epidemiology Branch

Health Effect Division (7509P)

Acting Branch Chief

Toxicology and Epidemiology Branch

Health Effects Division (7509P)

Charles W. Smith, Risk Assessor

Risk Assessment Branch VI

Health Effects Division (7509P)

, Chemical Review Manager

Risk Management & Implementation Branch II

evaluation Division (7508P)

Based on the low frequency and severity of incident cases, 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 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF CHEMICAL SAFETY AND

OLLUTION PREVENTION

Ver.Apr.08

Based on the low frequency and severity of incident cases, there does not appear to be a concern 

continue to monitor the 

incident information and if a concern is triggered, additional analysis will be included in the risk 
Page 2 of 3

II. 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. 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. 

III. BACKGROUND

For this evaluation, the OPP Incident Data System (IDS) was utilized for pesticide incident data 

on the active ingredient metsulfuron (PC Code 122010). The purpose of the database search is to 

identify potential patterns on the frequency and severity of the health effects attributed to 

metsulfuron exposure. The 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 compiles these reports in IDS. IDS contain

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. 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.

IV. RESULTS/DISCUSSION

IDS records incidents resulting in higher severity outcomes in more detail, in a module called the 

Main IDS module. This system stores incident data for death, major and moderate incidents, and 

it includes more details 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. The less severe human incidents (minor, 

unknown, or no effects outcomes) are reported by registrants as counts called aggregate 

summaries and are recorded in a separate module called Aggregate IDS. 

In Aggregate IDS, from January 1, 2006 to March 31, 2011 there are 37 incidents involving 

metsulfuron. Because it falls within the categories reported as counts (which includes minor, 
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unknown or no effects), there is no unique report that provides details about the incident and 

single chemical incidents are not distinguished from multiple chemical incidents; however, a 

high frequency of incidents indicates there is a high potential for exposure and vice versa. For 

metsulfuron, there appears to be a low potential for exposure. 

For the Main IDS, from January 1, 2006 to March 23, 2011, there are 12 cases reported that 

involve the active ingredient metsulfuron. However, there is no incident reported for single 

chemical metsulfuron only in the database. 

Metsulfuron is not included in the AHS, and therefore does not provide information for this 

report.

Based on the low frequency and severity of incident cases, 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.