### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C . 20460 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### MEMORANDUM Date: August 29, 2013 SUBJECT: Metam Sodium, Metam Potassium, MITC : Review of Human Incidents PCCode:039003 , 039002 , 068193 Decision No.: 477549 Petition No.: NA Risk Assessment Type: NA TXRNo.:NA MRID No .: NA DP Barcode: 04 I4492 Registrat

. ion No.: NA Regulatory Action: NA Case No.: NA CAS No.: 6734-80-1 , 137-42-8 40CFR: NA Ver.Apr.08 

### FROM: Elizabeth Evans, Environmental Protection Specialist

### ~ Toxicology and Epidemiology Branch

### f~~ Health Effec t s Division (7509P)

- 

## 0-- and

## hanna Recore, Industrial Hygienist Toxicology and Epidemiology Branch Health Effects Divi sion (7509 P) THROUGHfbavid J. Miller, Acting Branch Chief Toxicology and Epidemiology Branch Health Effects Division (7509P) TO: Shalu Shelat, Risk Assessor Risk Assessment Branch VI Health Effects Division (7509P) and Jose Gayoso, Chemical Review Manager Risk Management & 

### Implementation Branch II Pesticide Reevaluation Division (7508P) Summary and Conclusions In the 2008 Reregistration Eligibility Decision (RED) for Methyldit hiocarbamate Salts (Metam sodium, Metam potassium) and Methyl Isothiocyanate (MITC), EPA identified acute inhalation as the main risk of concern for handlers (including persons involved in the application, and also

Page 1 of8persons involved in tarp perforation and removal activities), workers, and bystanders. 1 While there is a low frequency of incidents reported in IDS and SENSOR-Pesticides for Metam potassium and MITC, SENSOR-Pe sticides data does support the inhalation risk of concern id entified in the RED for metam sodium due to the frequency ofreported incidents ( n = 131) and number of reported respiratory effects (59% of cases). On December 1 , 2012 the final phase EPA-required new safety measures for soil fumigant pesticides (chloropicrin , dazomet, metam sodium , metam potassium , and methyl bromide) went into effect. These safety measures are required to increase protection for ag ricultural workers and bystanders. At the time of this report , there is insufficient information available to determine if the newly required safety measures have impacted the frequency of incidents occurring since implementati on. However, the Agency will continue to monitor the incident information and provide an updated review of incident, considering pre- and post-mitigation i ncidents separately, when the information becomes avail ab le. The Agency w ill continue to monitor the incident information and provide an updated review of incident, considering pre- and post-mitigation incidents separately , when the information becomes available. " The Agricultural Health Study (AHS) is also a potential sou rce of informati on associated with human health effects associated with certain pesticides. These chemicals are not included in the AHS, and therefore this study does provid e information for this report. Detailed Review 

### I. ACTION REQUESTED This re view 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 registrati on review. Reports of adverse health effects allegedly due to a specific pesticide exposure (i.e ., an "incident") are largely self-reported and therefore, generall y s p eaking , neither exposure to a pesticide or reported symptom (or the connection between the two) is validated o r otherwise confirmed. Typically, causation cannot be determined based on incident data. How ever , incident information can be an important source of feedback to the Agency: incid ents of severe outcome , or a suggested pattern or trend among less severe incidents, can signal the Agency to further investigate a particular chemical or pro duct. Observational epidemiology stud ies relate the risk of disease , 

### e.g. , cancer, and exposure to an age n t such as a pesticide product in the general population or specific sub-groups like pesticide applicators. 

### II. BACKGROUND Metam sodium and metam potassium are non-select ive so il fumigants with fungicidal , herbicidal, insecticidal , and nematicidal properties. MITC is highly volatile and is responsible for the fumigant properties of metam sodium and metam potassium. Metam sodium and metam potassium are used on a wide range of pe sts including fungi, plants , insects , a nd nematodes. As an a gricultural soil fumigant, it is currently labeled for use on all food , feed, and fiber crops . 

### It

1 http: // www.epa.gov/oppsr rd 1/reregistration / REDs/ metamsodium-red.pdf Page 2 of8

### also i s used pre-plant on turf grass, to control invading plant roots in drains and sewers , and for vegetation control along drained ponds and lake s (in California only)

. Metam sodium, metam potassium, and MITC are all registered as antimicrobial agents to control a number of microbiological pests , including bacteria and fung i. There are no residential uses. At the time of the RED, metam sodium had 39 registered uses whereas metam potassium had only 16 and MITC had one. Metam sodium is "one of the most widely us ed chemicals in agricultural in the United States

. .. " 2 

### For this evaluation, both the OPP Incident Data System (IDS) and the Centers for Di sease Control and Prevention/National Institute for Occupational Safety and Health (CDC/NIOSH) Sentinel Event No tification Sys tem for Occupational Risk-Pesticides (S ENS OR) databases were consulted for pesticide incident data on the active ingredient Methyldithiocarbamate salts and MITC (PC Code: 039003,039002, and 068193). The purpose ofthe database search is to identify potential patterns in the frequency and severity of the health effects attributed to Methyldithiocarbamate salts and MITC exposure. In addition, findings from the AHS were reviewed. The Agricultural Health Study (AHS) is a high quality, prospective epidemiology study evaluating the link between pesticide use and various health outcomes including cancer . T hese chemicals are not included in the AHS

.


### III. RESULTS/DISCUSSION a. IDS (Incident Data System) OPP's IDS includes reports of alleged human health incidents from various sources, includ ing mandatory Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) Section 6(a)(2) reports from registrants, other federa l 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 informat ion rec orded. Reports submitted to the IDS represent anecdotal reports or allegations only, unless otherwise stated in the report
. ID S records incidents in one of two modules: Main ID S and Aggre gate 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 death, major and moderate incidents, and it includes information about the location, date and nature of the incident. Mai n IDS incidents involving only one active ingredient (as opposed to pesticide products with multiple active ingredi ents) are considered to provide more certain information about the potential effects of exposure from the pesticide.

2 R£0 Fact Sheet: Methyl dithiocarbamate Salts

- Metam Sodium/Potassium and MITC: http: //www.epa.gov/oppOOOO 1 / chem search/reg actions/reregistration/fs G-56 l 0-Jul-08

.pdf 

### Page 

### 3 of8o Aggregate IDS contains incidents resulting in less severe human incidents (minor, unknown , or no effects outcomes). T h ese are reported by regi s trants only as counts in what are aggregate summaries. Metam Sodium: For the Main IDS , from January 1 , 2008 to February 19 , 2013, there were 5 incidents reported for single chemical only in the database. There was 1 additional incident reported involving more than one chemical. All ofthese incidents were classified as mode rate sever ity generally involving ocular, respi ratory , gastrointestinal , and dermal effects. Overall , there are few incidents involving metam sodium reported to IDS. In Aggregate ID S , from J anuary 1 , 2008 to February 19 ,2013, there were 8 reported incidents involving metam sodium. These incidents were c l assified as minor severity. Metam Potassium (039002): For the Main IDS , from January 1 , 2008 to Feb ru ary 19 , 2013 , there was 1 incident reported for metam potassium in the database. This incident was classified as moderate severity which cons isted of ocular sympto ms. Overall , there are few incidents involv ing metam potassium reported to ID S. In Aggregate IDS , from January 1, 2008 to February 19, 2013, there wa s 1 reported incident involving metam potass ium. This incident was classified as minor severity. MITC: For the Main IDS , from January 1, 2008 to February 19 , 2013 , there was one incident reported in the database involvin g M ITC. This incident was classified as moderate severity and consisted of re spirator y and neurological effects. In Aggregate IDS , from J anuary 1, 2008 to February 19 , 2013, there were 

### 3 reported incidents involving MITC. The se incidents were classified as minor severity. b. SENSOR-Pesticides The SENSOR-Pesticides database covers 11 states from 1998-2009 , although reporting varies from state to state. Cases ofpesticide-related illnesses are ascertained from a variety of sources , including: reports from local Poison Control Centers, state Department of Labor workers ' co mpensation claims when reported by physicians , reports from State Departments of Agriculture , and phy s ician reports to state D epartments 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 providin g that information. The s tate coordinator at eac h of the 11 respective s tate Departments of Health conducts case followup activitie s such as obtaining medical records to verify symptoms and severity

. Using s tandardized protoco l and case definitions deriv ed from poison center reporting , the state SENSOR-Pesticide coordinator enters the incident information into the s tate- based system which is sent to 

### NIOSH annually to be aggregated.

Page 4 of8

### Metam Sodium (039003) A query of SENSOR-Pe sticides 1998-2009 identifies 136 cases, s temming from 60 events, for metam sodium. One hundred thirty one cases involved a s ing le active ingred ient and 5 cases involved multiple active ingredients. Ofthe 131 single active ingredient cases: 2 were high in severity, 24 were moderate in severity and 105 were low in severit y. The high and moderate severity case descriptions are provided in Table 2. One hundr ed and four cases were workrelated. Ni nety three ofthe 131 cases were exposed via drift/volati li zation3

. 

### Reported health effects are summarized in Tab le 1.

Table 1

. SENSOR-Pesticides 1998-2009: Reported Health Effects for Metam Sodium Cases N = 1 3 1
Health Effect # of Occurrences Dermal 32 Ocular 80 Respiratory 77 Gastrointestinal 62 Renal 3 Nervous System 72 Cardiovascular 13 Misc. 14



### * Cases may report multiple health effects 

### Multiple case drift/volatilization events (Only events with 15 or more cases are described here.) 1. The first metam sodium drift/volatilization event reported to SENSOR occurred in Somerton, Arizona in 1999 and res ulted in 19 SENSOR case report s after an application of the soil fung icide Nemasol426 (EPA reg # 5481

-423

- 34794) was made to field via sprinkler chemigation in preparation for planting cilantro. Field laborers 1/3 of a mil e away from the app lication had inhalation exposure due to the application drift/volatilization. Workers experienced symptoms including burning and tearing ofthe eyes, upper respiratory pain and shortness of breath. Pesticide application violations were cited in this event but not specified further in the dataset. The event (AZ00053) is described in SENSOR as fo ll ows: On September 16, 1999, the Arizona Department of Agriculture (ADA) representative faxed a report of a pesticide exposure incident and the cluster of illnesses to the Office of Environmental Health (OEH). The gender and the age range for 32 of 35 crew members are: 17 males, 15 females and 20 through 52 years of age. On September 12, 1999 , the applying company had scheduled and applied the pesticide Nemaso/426, at 7:00p.m

. , by the sprinkler

3 The SENSOR-Pesticides program defines drift as "

.. .the movement of pes t icides away from the treatment site. The pesticide spray, mist, fumes , or odor are carried from the target site by air." There is no clear distinction between cases exposed from volatilization versus spray drift when analyzing the SENSOR-Pesticides data

. 

### Page 5 of8Case 10 AZ00097

AZ00 1 19

AZOO I 34 CA03433 CA03520 irrigation (ch emi gation ) method, to an agricultural field in preparati on for planting cilantro. The .field is lo ca ted in Somerton, Arizona

. The Nemaso/426 is a soil fungicide, but is consider ed a

fumigant that co ntains 42% sodium ethyldithiocarbamate, as the active ingredient. Nemasol 426 has a strong sulfur-like odor. Its vapors and aerosols can irritate eyes, nose and the respiratory passages. The Environmental Protection Agency (EPA) Registration Number for Nemaso/426 is 5481-423-34794, as provid ed on the pesticide label. 

### 2. Another drift/vo latilization event occurred in California in 2008 and resulted in 18 SENSOR case reports. Workers 

### in a lett uce field were exposed via drift/volatilization from a nearby application ofVapam HL soil fumigant to a spinach field. Workers experienced symptoms including burning eyes and upper respiratory pain. A pesticide application violation was c ited for this event but n ot further specified in SENSOR. The event (CA02555) was described as fo ll ows" Workers were in lettuce field while spinach field was treated- exposed via drift" 3. Another drift /vo latilization event occurred in Washington in 2008 involving a product named Metam CLR and resulted in 19 case reports; 16 of which were residential cases including several young children. Symptoms experienced inc lude eye burning/irritation , cough and upper respiratory pain. The event (WA02238) is described in SENSOR as fo ll ows: On Friday Oct 17, a strong odor consistent withfumigant vapors was reported in a residential area aqjacent to a treated field. DOH was able to collect informat ion on 16 of the 19 people who lived there. The 16people includedfive children aged 17 days to six years old, four children aged 12-18 years old, and seven individuals aged 19-65 years old. All 16 reported eye irritation. Tearing, headache, nausea , abdominal cramping, coughing , s hortn ess of breath, and burning in the nose and throat were also reported. Twelve of the 16 sought health carefor symptoms. In addition , two visitors and an emergency responder reported exposure and irritant symptoms but did not seek health care. This incident occurred during application of a soil fumigant, through the central pivot irrigation system, on a 150 acre crop circle across the road. It appeared that temperature inversion on the afternoon of the 17th contributed to the off-site movement of vapors into the nearby homes. Strong smell in the residential area ...


# I Year 

# I Severity 1999 M oderate Mod erate 1999
Moderate 1999 1998 Moderate !998 Moderate Table 2. SENSOR-Pesticides 1998-2009 High and Moderate Severity Metam Sodium Cases (039003) 

# I Case Narrative

Inhalation exposure from a drifted pe s ticide. Sprinkler c hemi gation was used in a field one-third of a mile away. Inhalation exposure from a drifted pesticide

. Sprink l er chemigation was used in a field one-third of a mile away.

Water with metam sod ium soa ked the truck driver's shoes. feet. pants and legs. Dermal exposure. No case detail provided No case detail provided 

### Page 6 of8Table 2. SENSOR-Pesticides 1998

- 2009 High and Moderate Severity Metam Sodium Cases (039003) Case ID 

## I Year 

## I Severity 

## I Case Narrative CA05474 1998 Moderate No case detail provided Moderate Delivering truck of metam sodium, stepped in dry white powder getting on his sock and boot chemically CA06367 1999 burning both feet CA06829 1999

. Moderate No case detail provided CA06887 1999 Moderate No case detail provided CA06895 1999 Modera.te No case detail provided CA07997 1999 Moderate No case detail provided CA07999 1999 Moderate No case detail provided CA08837 20 0 1 Moderate No case detail provided CA09020 2001 Moderate No case detail provided CAI0390 2002 Moderate No case detail provided CAI2060 2002 Moderate No case detail provided CAI3157 2003 Moderate No case detai l provided CAI3925 2004 Moderate He was hooking up sprinkler irrigation pipes when he entered a field that had been treated with vapam CA I4291 2005 High Exposed to pesticide drift when she entered a field in the morning after a nearby field was sprayed overnight Moderate He was applying pesticide by tractor next to a tield where another chemical was being applied by CAI4397 2005 sprinklers. FL02210 2007 Moderate 27 yr old got Vapam HL on his feet 2 days ago. He removed hi s soc ks and rinsed with water that day . FL03224 High Patient came into contact with Vapam. OR00215 1999 Moderate Was walking outside along road; saw huge cloud sitting over field. 50 ft from house; cloud came o ve rhead ; became symptomatic. Moder ate A 41 y / o male was exposed when transferring product. Product s pilled onto his boots and when he WA01287 2003 attempted to wash it off. Do Moderate On Friday Oct 17, a strong odor consistent with fumigant vapors was rep orted in a residential area WA02736 2008 adjacent to a treated field Moderate On Friday Oct 17, a strong odor consistent with fumigant vapors was reported in a residential area WA02742 2008 adjacent to a treated field *SENSOR-Pesticide s Severity Index Death Human Fatality High Life threatening, requires >5 days lo st work/time treatment Moderate I nvolves systemic effects 3-5 days lost work/time
Minor Symptoms typically resolve <3 days lost work/time without treatment 

### Metam Potassium (pc code 039002) A query of SENSOR-Pesticides 1998

- 2009 identifies 3 cases, stemmin g f rom 3 events, involving metam potassium; all 

### 3 were single ai cases. Two cases were lo w in severi ty and one was Page 

### 7 of8

### moderate in severity. The moderate severity case desc ri ption states "

... experienced ocular and dermal s ymptoms after walking th rough his property that was overflowed with runoff from a potato fi e ld chemigation application. He wore irrigation boot s and one boot had a hole in it. This res ulted in a chemical burn to his foot. WSDA samples tes ted pos itivefor residues from the adjacent chemigation application. " Methyl isothiocyanate (MITC); ( pc code 068103) A query of SENSOR-Pesticides 1998-2009 identifies 2 cases , s temming from 2 events, involving MITC. Both cases involved exposures to multiple active ingredients. One case was low in severity and one case was moderate in severity. No narrative was recorded for either case.

c. Agricultural Health Study (AHS) The AHS is a high quality, prospec ti ve epidemiology s tudy eva luating the link between pesticide use and various he alth outcomes including cancer. The AHS includes private and commercial pesticide app li cators and their spou ses . 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. Metam Sodium, Metam Potassium and MITC are not included in the AHS. IV. CONCLUSION A number o f cas es involving metam sodium, particularly cases of occupational drift/volatilization , have been reported to SENSOR-Pesticides, including 2 multiple case drift events in 2008. Although most of these cases were low in severity ; considering the frequency of reported incidents , this i s a chemical ofpotential concern for both agricultural workers and bystanders. The frequency of incidents is likely related to the widespread use of the product in agriculture. With consideration for the mitigation efforts (wh ich include both u se and entry restriction s, additional PPE for app li cators, expanded buffer zones) implemented; HED will continue to monitor the incident information as it becomes avail able and will provide an updated review of incidents during regi stration review. Based on the low frequency and severity of incident cases reported for Metam Potassium and MITC in both IDS and NIOSH SENSOR-Pe sticides , there doe s not appear to be a concern at this time that would warrant further investigation. The Agency will continue to monitor the incident informati on and if a concern is triggered , additional analysis will be included in the risk ass e ss ment.

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