UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

MEMORANDUM 

Date: December 15, 2015 

SUBJECT: Metaldehyde: Review of Domestic Animal Incidents 

PC Code: 05300 I 

Decision No.: 51 11 80 

Petition No.: A 

Risk Assessment Type: NA 

TXR No.: NA 

MRID No.: A 

DP Barcode: 0430204 

Registration No.: NA 

Regulatory Action: A 

Case No.: NA 

CAS No.: 108-62-3 

40 CFR: NA 

Vcr.Apr.08 

FROM: Shanna Recore, Industrial Hygienist J\O. ll "· 1 11 P,... 1,1 n . 

Toxico

Health 

l

Effects 

ogy and 

Di

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vis

pidemiolog

ion (7509P) 

y Branch a .J::lf'W

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T HROUGH: 

TO: 

David J. Miller, Acting Branch Chief / <t• J 

Toxicology and Epidemiology Branch 

Health Effects Division (7509P) 

Ronnie Bever, Risk Assessor 

Risk Assessment Branch Vll 

Health Effects Division (7509P) 

); /c)<JCL-W5 

and 

Leigh Rimmer, Chemical Review Manager 

Risk Management & Implementation Branch I 

Pesticide Re-evaluation Division (7508P) 

and 

Melissa Panger, Ph. D., Senior Science Advisor 

Environmental Risk Branch 2 

Environmental Fate and Effects Division (7507P) 

Summary and Conclusions 

In the 2006 Registration Eligibility Decision (RED) for Metaldehyde 1

, the Agency found that 

risk to domestic animals were of concern because there were the number of poisoning incidents 

1 http://archive.epa.gov/pesticides/reregistration/web/pdf/metaldehyde_ red.pdf 

Page 1of6 
involving ingestion of metaldehyde products by domestic animals (primarily dogs) after 

application in residential settings, and incident info1mation also suggested that dogs also may 

ingest metaldehyde granules after opening product packaging. In the 2006 RED, the Agency 

implemented a number of label and formulation requirements to address the risk to domestic 

animals. The formulation mitigation required all residential use products containing metaldehyde 

to be formulated with a bittering agent approved by the Agency, at sufficient concentration to 

deter ingestion by domestic animals. 

A query of IDS for metaldehyde (PC code: 05300 I) domestic animal incidents from January 1, 

2010 to September 24, 2015, found 11 30 reported domestic animal incidents. These incidents 

included 125 deaths and 59 major severity incidents associated with metaldehyde reported to 

IDS. A query of NPIC for metaldehyde from 2010 to September 2015 found 102 reported 

animal incidents. These incidents included two deaths and three major severity incidents. A 

closer review of the NPlC incidents indicates that the animals are often being exposed by 

ingesting pellets that have been applied by the owners to their yard or garden. 

A trend of the IDS data, from 20 I 0 to 2014, shows an apparent decrease in incidents over time. 

In general the reduction in poisoning events over time after 2012, is likely due to the product 

cancellations that took place at the time of the metaldehyde RED. 

Additional analysis may be performed during registration review to determine if the mitigations 

implemented will continue to impact the frequency of incidents. 

Detailed Review 

I. ACTION REQUESTED 

TEB has been asked to review the domestic animal incidents in IDS associated with metaldehyde 

to support the metaldehyde scoping document. 

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 

confinned. Typically, causation cannot be detennined based on incident data and a certainty 

index is rarely assigned to incidents reported in the IDS. The symptoms or signs experienced by 

the animal may have been unrelated to pesticide treatment or may have been due to misuse of the 

product. 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. 

II. BACKGROUND 

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

ornamental plants. In the 2006 RED, the Agency found that risk to domestic animals were of 

concern because there were the number of poisoning incidents involving ingestion of 

Page 2of6 
metaldehyde products by domestic animals (primarily dogs) after application in residential 

settings, and incident information also suggested that dogs also may ingest metaldehyde granules 

after opening product packaging. In the 2006 RED, the Agency implemented some labeling and 

fonnulation requirements to address the risk to domestic animals. The formulation mitigation 

required all residential use products containing metaldehyde to be formulated with denatonium 

benzoatc, or another bittering agent approved by the Agency, at sufficient concentration to deter 

ingestion by domestic animals. 

For this evaluation, OPP Incident Data System (IDS) database was 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 to domestic animals. 

Ill. RESULTS/DISCUSSION 

a. Incident Data System (IDS) 

Incident Data System (IDS) is a database maintained by OPP and houses pesticide incidents 

reported to the Office. IDS is comprised mostly of pesticide incident data submitted by 

registrants in response to the Federal Insecticide Fungicide and Rodenticide Act (FIFRA) section 

6(a)(2). This is a part of FIFRA that mandates registrants report pesticide incidents of which they 

become aware to OPP. IDS also includes other pesticide incidents reported directly to EPA by 

citizens and other organizations and agencies. IDS includes infonnation on incidents involving 

humans, plants, and wild and domestic animals where there is a claim of an adverse effect, as 

well as detects of pesticides in water. 

IDS records incidents in one of two modules: Main IDS and Aggregate IDS, each described 

below: 

• Main IDS includes incidents that are reported in more detail, often with narrative 

information describing the circumstances of the incident: registrants are required to 

include more detailed information if the incident they are reporting involves humans and 

a higher severity outcome, although some incidents involving domestic animals are 

submitted as detailed reports and thus entered into Main IDS. For the Main IDS, from 

January I, 20 I 0 to September 24, 2015, there were two domestic animal incidents 

reported for metaldehyde in the database. One was a death and the other was a major 

severity. The reported death incident was involved a dog and was associated with 

Registration No. 71096-1 3. No furiher details were provided. The major severity 

incident involved a dog who ingested product pellets that were appli ed to a garden. 

• Aggregate IDS consists of counts of exposures and severity index associated with a 

particular product or active ingredient, and registrants nonnally submit no narrntive 

information with these counts.2 Because EPA 's reporting requirements allow registrants 

2 Note: Main IDS is organized by incident (and each incident has a unique report associated with it), whereas as 

Aggregate Summary IDS is organized by counts of exposures (each with a designated .. exposure severity type") 

associated with each pesticide product for a certain time period. 

Page 3of6 
to submit domestic animal incidents (DA, DB, DC, DD, and DE) as aggregate exposure 

counts and exposure severity and provide no narrative details, the majority of the 

domestic animal data are merely counts of exposure severity types, by year and entered 

into the Aggregate (and not Main) IDS Module. For the Aggregate IDS, from January l , 

20 I 0 to September 24, 2015, there were 1128 domestic animal incidents reported 

involving metaldehyde the database. 

Although they di ff er in level of detail, Main and Aggregate IDS collect both the severity of the 

exposure (called an "exposure severity type" in IDS) and the pesticide and/or pesticide product 

involved (when the information is provided by the person reporting the incident). The focus of 

this report is domestic animals/pet, and the IDS exposure severity types for domestic animals, as 

defined by 40 CFR § t 59.184, are as follows: 

• DA - Death - if the domestic animal died or was euthanized: 

• DB - Majo r - if the domestic animal exhibited or was alleged to have exhibited symptoms which may have 

been life-threatening or resulted in residual disability; 

• DC - Moderate - if the domestic animal exhibited or was alleged to have exhibited symptoms which are 

more pronounced , more prolonged or of a more systemic nature than minor symptoms and inc luded some 

treatment and return to pre-exposure state; 

• DD - Minor - if the domestic animal was alleged to have exhibited symptoms, but they were minimally 

bothersome and resolved rapidly; 

• DE - Unknown - if symptoms are unknown or not specified. 

A total of 124 deaths were reported to Aggregate IDS which means that the domestic animal died 

or was euthanizcd. There were 58 major incidents in which symptoms may have been lifethreatening or caused residual disability. The remaining incidents were less severe: 758 

incidents were classified moderate which means that treatment may have been required but the 

animal returned to its pre-exposure state of health with no residual disability; 175 incidents were 

classified minor which means that symptoms may have been minimally bothersome and resolved 

rapidly; l 0 incidents were unspecified and may have been either moderate, minor, or were 

unspecified and three incidents were classified as unknown severity. Breakdown of the incidents 

reported to both Main and Aggregate IDS by severity classification is found in Table 1. 

Table I. Metaldehyde Domestic Animal Incidents in IDS (Main and Aggregate) from J anuary 1, 2010 to 

September 24, 2015 

Code Severity Aggregate Summary 

Module 

DA Fatality 125 

DB Major 59 

DC Moderate 758 

DD Minor 175 

DE Unknown 3 

D-C, Mod, 10 

D, E Minor, 

Unspecified 

Total 1130 

Page 4of6 
A trend over time from 20 I 0 to 2014 was analyzed (Figure I). The number of reported incidents 

appears to peak in 2011 and then begins to decline slightly in 20 12 and continued to decline into 

2014. In 20 14, the number ofreported incidents {n=9 1) has decrease 70% from the number of 

incidents reported in 20 11 (n=309). As mentioned above, several label and fonnulation 

mitigations were implemented in the 2006 RED. These mitigations may be contributing the 

apparent decrease in incidents shown below. Although, these mitigations were implemented in 

the 2006 Meta ldehyde RED, most of the products did not adopt changes until 20 1112012 and 

some products may have entered the market a couple years after that. 

Figure I. Metaldehyde Domestic Animal incidents Reported to IDS from 20 10 to 2014 

350 

300 

~ 

~ 250 -0 

~ 200 ._ 

0 

~ 150 .0 

E 100 :::l 

z 

so 

0 

2010 2011 2012 

Year 

2013 

• death • major severity • moderates and minors 

2014 

Out of the 16 products associated with metaldehyde domestic animal incidents reported to IDS, 

the most implicated product is Con-y's Slug & Snail Pell ets (MP) (Registration No. 8 119-13), 

reportedly used in 48% {n=542) of the metaldehyde domestic animal incidents. This is followed 

by Co1Ty's Slug & Snail Pellets (3.25) (Registration No. 8 11 9-1 3), and OR-CAL Slug & Snail 

Bait (Registration No. 7 1096-00007), reportedl y used in 23% (n=263) and 12% (n= l3 1) of the 

metaldehyde domestic animal incidents, respecti vely. These products are pellets that contain 

3.25% of the active ingredient metaldehyde and are used around gardens to treat for snails and 

slugs. 

b. National Pesticide Information Center (NPIC) 

The National Pesticide Jnfonnation Center or NPIC is a cooperative effort between Oregon State 

University 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, NP IC's primary 

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

Page5of6 
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 callers and records that infonnation 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 IDS, NPIC provides an additional source of infonnation to see 

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

additional information about the same incident(s). 

One hundred and two animal incident involving metaldehyde were reported to NPIC from 20 I 0 

to September 20 15. Exposures to the following species were reported dogs (n=9 l ), cats (n=8), 

potbellied pig (n= 1 ), miniature horse (n= I) and bluebird (n= I). Of these incidents, 65 dogs, 1 

cat, and I potbellied pig were reported to have ingested the product. Of the ingestion incidents 

two animals died (both dogs). One dog was found dead in neighboring agricultural fields that 

had been treated with metaldehyde. The other dog chewed up a box of the product and was 

euthanized after experiencing panting and tremors. Three incidents were classified as major 

severity, I 0 incidents were classified as moderate severity, nine incidents were classified as 

minor severity, seven incidents were classified as having symptoms consistent with metaldehyde 

exposure, and 36 incidents were classified as asymptomatic. 

IV. CONCLUSION 

In the 2006 Registration Eligibility Decision (RED) for Metaldehyde3

, the Agency found that 

risk to domestic animals were of concern because there were the number of poisoning incidents 

involving ingestion of metaldehyde products by domestic animals (primarily dogs) after 

application in residential settings, and incident infonnation also suggested that dogs also may 

ingest metaldehyde granules by opening product packaging. In the 2006 RED, the Agency 

implemented a number of label and fonnu lation requirements to address the risk to domesti c 

animals. 

A query of IDS for metaldehyde (PC code: 05300 1) domestic animal incidents from January I, 

20 I 0 to September 24, 2015, found I 130 reported domestic animal incidents. These incidents 

included 125 deaths and 59 major severity incidents associated with metaldehyde reported to 

IDS. A query ofNPIC for metaldehyde from 20 10 to September 20 15 found 102 reported 

animal incidents. These incidents included two deaths and three major severity incidents. A 

closer review of the NPIC incidents indicates that the animals are getting exposure from 

ingesting pellets that have been applied by the owners to the yard. 

A trend of the IDS data, from 2010 to 2014, shows an apparent decrease in incidents over time. 

In general the reduction in poisoning events over time after 2012, is likely due to the product 

mitigations that were required in the 2006 metaldehyde RED and implemented in 2011 /2012. 

Additional analysis may be performed during registration review to determine if the mitigations 

implemented will continue to impact the frequency of incidents. 

3 http://archive.epa.gov/pesticideslreregistration/web/pdf/metaldehyde_red.pdf 

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