UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

MEMORANDUM 

Date: November 12, 2015 

SUBJECT: Metaldehyde: Tier I (Scoping) Review of Human Incidents and Epidemiology 

PC Code: 05300 I DP Barcode: 0430090 

Decision No.: 509276 

Petition No.: NA 

Risk Assessment Type: NA 

TXR No.: NA 

MRIDNo.: NA 

Registration No.: NA 

Regulatory Action: NA 

Case No.: NA 

CAS No.: I 08-62-3 

40 CFR: NA 

Ver.Apr.08 

Elizabeth Evans, Environmental Protection Specialist /' __.-> FROM: 

Toxicology 

Health Effects 

and 

Division 

Epidemiology 

(7509P

Branch 

) 

c.; 

v 

J.;..~ J ~ 

and 

Shanna Recore, Industrial Hygienist A A 

Toxicology and Epidemiology Branch ..@ 

Health Effect Division (7509P) · 

J

r ;///ft. /A-1111- 1.11 .S 

THROUGH: David Miller, Acting Branch Chief 

Toxicology and Epidemiology Branch 

Health Effects Division (7509P) 

TO: Ronnie Bever, Risk Assessor 

Risk Assessment Branch VI 

Health Effects Division (7509P) 

and 

Leigh Rimmer, Chemical Review Manager 

Risk Management & Implementation Branch 2 

Pesticide Re-evaluation Division (7508P) 

Summary and Conclusions 

Based on the severity of incident cases reported for metaldehyde in both IDS and SENSORPesticides, 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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Detailed Review 

I. ACTION REQUESTED 

This review is intended to fulfi ll 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 ~ub groups like pesticide applicators. 

II. BACKGROUND 

Metaladehyde is a molluscide used to kill snail and slug pests of various food, seed, and ornamental 

plants. 

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 metaldehyde (pc code: 053001). The purpose 

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

effects attributed to metaldehyde exposure. Metaldehyde is not included in the AHS, 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 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 specifics. This system stores incident data for 

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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, 2010 to September 24, 2015, there were 31 incidents reported 

for the single chemical metaldehyde only in the database. Thirty incidents were classified as 

moderate severity and one incident was classified as major severity. An adult male was 

spreading bait on a windy evening. He thought he inhaled the product dust. The next day he 

developed nausea, vomiting, sweating and drooling. He was admitted to the hospital but his 

health care provider did not think his symptoms were related to the product. There were 13 

additional metaldehyde incidents reported to Main IDS involving more than one active 

ingredient. 

In Aggregate IDS, from January 1, 2010 to September 24, 2015, there were 104 incidents 

reported involving metaldehyde. These incidents were classified as minor severity. 

b. SENSOR-Pesticides 

The SENSOR-Pesticides database covers 12 states from 1998-2011, 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 12 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 from 1998-2011 identifies a total of 58 cases involving 

metaldehyde, 47 of which involve a single ai. Of the single ai cases, five were classified as 

moderate in severity and 42 were classified as low in severity. Fifteen cases were work-related 

and 32 cases were not work-related. Most cases (90%) involved exposure to snail/slug bait 

granules. 

Location of Case Exposure 

• 57% occurred at private residences 

• 15% occurred at schools 

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o In Washington State in 2011, five students ages 12-14 were sent to clean up a school 

greenhouse. The product spilled during clean up and the students reported 

stomachaches and headaches to the school nurse. 

• 13% occurred at retail establishments 

Case Exposure Route Information• 

• 66% of cases (n=31) were exposed from inhalation of the product. 

o Twelve of these inhalation cases resulted from spill of the product, including seven 

inhalation cases involving spill or leak of product onto retail employees including 

cashiers and stockers. 

o Five inhalation cases occurred at the school greenhouse. 

o Fifteen inhalation cases occurred when the case was applying the product; eight of 

these cases specifically note that wind "picked up" or "changed direction" during the 

application. 

• 40% of cases (n=l 9) were exposed dermally. 

• 25% of cases (n=12) were exposed from ingestion of the product including 6 homeowner 

applicators who got product in their mouth from applying while windy. 

Case Activity at Time of Exposure 

• 40% of cases were applying the product 

• 11 % of cases were transporting the product 

• 17% of cases were at work not involved in application. All eight of these cases were 

retail establishment employees. See Table 3 for these case descriptions. 

Symptoms Reported 

Nausea (n=l 5), respiratory irritation (n= l 7), headache (n=l 4) were among the symptoms 

re po rt e d 

Table I. SENSOR-Pesticides 1998-

2011 

Symptoms reported for metaldehyde 

cases (n=42) 

Respiratory 23 

Gastrointestinal 23 

Nervous System 22 

Dermal 15 

Ocular 8 

Cardiovascular 2 

Renal 0 

*Cases may report multiple symptoms. 

'.faBle 2. SENSOR-Pesticide5 1998-2011 

Moderate Severity Cases involving metaldehyde (pc code 053001) 

Case ID Year Case Description 

OROl227 2005 Child was playing in grass and around plants where slug bait had been applied earlier 

' Cases may report multiple exposure routes. 

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A 61 y/o male reported that he got slug & snail product in his eyes. he experienced ocular 

WA02870 2008 symptoms. He phoned WPC two days after exposure and sought health care the next day. DOH 

was unable to reach the individual for an interview. but medical records indicate exposure 

could have contributed to ocular symptoms. 

A 63 y/o male developed an allergic reaction after applying loose meal bait for slugs in his 

WA02112 2006 home garden. He sought health care at the ER and later followed up with his private MD. 

There was no topical testing to confirm that metaldehyde was source of allergy. 

CA l 7020 2009 Bag of snail bait spilled open 

~ er 

Table 3. SENSOR-resticides 1998-2011 

Retail Worker Cases involving metaldehyde (pc code 053001) -

Case ID Year Case Description - ... -

A 30 year old pregnant female who had asthma was working as a cashier at a retail 

food center. She described picking up a container of the product and dust from it 

WA02230 2006 came up into her eyes. As she was wearing contacts. she took them out. washed her 

face. and went to a clinic for an exam. She continued 10 have dry eyes with them 

bothering her when she was awake. 

CAl4761 2007 Stocking shelves at Walmart pesticide spilled on him 

LA02706 2007 Cashier checked out bag of(snail and slug killer). bag leaking and inhaled cloud of 

dust 

TX03978 2004 Case works at Walmart and he was lifting a box. It broke open and spilled on case's 

body. He was reorganizing the department 

A 26 year old female garden shop employee for a retail store experienced an 

WA02117 2006 accidental facial exposure to dust from a slug control product. She sought medical 

care the same day for mild respiratory and neurological symptoms. Patient lost to 

follow-up. 

A 25 y/o female cashier at a retail store set down a box of slug bait and the dust. 

from an unobserved tear. puffed up on to her face and into her mouth. She 

WA02880 2008 experienced pain and irritation immediately and GI problems for two consecutive 

nights. She notified co-workers prior to washing off. She was seen at a clinic the 

following day. 

CA l2348 2003 Case was a 23 year old laborer/stocker who experienced an inhalation exposure at 

work that was classified as moderate in severity: no further details are provided. 

CA l4764 2007 Case was unloading an empty box that had some residue in it, inhaled some residue. 

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 formu lation/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 80 different pesticide 

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

therefore this study does not provide information for this report. 

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IV. CONCLUSION 

Based on the severity of incident cases reported for metaldehyde in both IDS and SENSORPesticides 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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