United States Chemical Safety December 2012 

Environmental Protection and Pollution Prevention 

Agency (7510P) 

 

Nabam 

Registration Review: 

Final Work Plan 

December 2012 

 

Docket Number: EPA-HQ-OPP-2012-0339 

www.regulations.gov

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Nabam Registration Review Team

Human Health & Environmental Effects

Nathan Mottl 

William Hazel 

Jonathan Chen 

Steven Malish 

Srinivas Gowda 

James Breithaupt 

William Erickson 

Risk Management

Wanda Henson 

Lance Wormell 

Office of General Counsel

Philip Ross 

________________________________________ 

Supporting documents for the Nabam Case may be found in the registration review docket EPAHQ-OPP-2012-0339 located on the internet at www.regulations.gov. 
Docket Number: EPA-HQ-OPP-2012-0339 

www.regulations.gov

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Introduction

This is the Final Work Plan (FWP) of the Environmental Protection Agency (EPA or “the 

Agency”) for the registration review of Nabam (Case 0641). The work plan includes the 

expected registration review timeline. The work plan also addresses public comments received 

concerning the Preliminary Work Plan (PWP) in the Summary Document which was posted in 

the Nabam registration review docket, and any other comments concerning the initial docket 

postings. The Summary Document provided information on what EPA knows about the pesticide 

and what additional risk analyses and data or information the Agency believes are needed to 

make a registration review decision. 

The Agency is implementing the registration review program pursuant to Section 3(g) of the 

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and will review each registered 

pesticide every 15 years to determine whether it continues to meet the FIFRA standard for 

registration. Changes in science, public policy and pesticide use practices will occur over time. 

The registration review program is intended to make sure that, as the ability to assess risk 

evolves and as policies and practices change, all registered pesticides continue to meet that 

statutory standard. The public phase of registration review begins when the initial docket is 

opened for each case. Information on this program is provided at: 

http://www.epa.gov/oppsrrd1/registration_review/. 

The Nabam Preliminary Work Plan (PWP) (PC Code 014503) was published on July 6, 2012 and 

the 60-day comment period ended on September 10, 2012. The Preliminary Work Plan document 

is available on www.regulations.gov docket number EPA-HQ-OPP-2012-0339. 

The first product containing Disodium ethylene bisdithiocarbamate (Nabam or EBDC) (PC Code 

014503) as an active ingredient was registered in the United States in 1948. Currently, there are 

eight products containing EBDC as an active ingredient registered with EPA. Algicide, 

bactericide, fungicide, slimicide, and microbicide/microbistat in industrial process and water 

systems such as air washer water, cooling tower water, drilling fluids, evaporative condenser 

water, heat exchanger systems, flood water, flue gas desulferization thickeners, fracturing fluids, 

industrial recirculating water cooling tower, oil recovery drilling mud, oil recovery packer fluid, 

oilfield drilling muds, workover or completion fluids, oilfield water treatment and water floods, 

petroleum industries, secondary and tertiary petroleum recovery, secondary oil recovery injection 

water, pulp and paper mill fresh water, pulp and paper mill systems, sugar beet processing 

equipment, sugar beet processing water, sugarcane processing water, sugar industries, sugar beet 

juice, sugarcane juice, sugarcane mill systems, sugarcane processing equipment, beet sugar mills, 

and cane sugar mills. Nabam is also used as a preservative in hydrocarbon fuels, lubricants and 

hydraulic fluids. Nabam is a member of the Ethylene bisdithiocarbamate (EBDC) group of 

chemicals which are metabolized to ETU (ethylene thio urea) in the body and in the 

environment. 

There are no EPA established tolerances or exemptions from the requirement of tolerances for 

nabam. FDA has deemed the indirect food additive use of nabam safe when used as a slimicide 

in paper/paperboard production with no maximum treatment concentration specified (21 CFR 

176.300). FDA has also deemed the secondary direct food additive use of nabam safe when used 
Docket Number: EPA-HQ-OPP-2012-0339 

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as an antimicrobial in sugar production at 3 ppm expressed in terms of the raw sugar beets or 

sugarcane [21 CFR 173.320(b)(2) and –(3)]. 

The Agency completed a Reregistration Eligibility Decision (RED) for Nabam in 1995. 

Documents associated with the registration review of Nabam can be viewed at 

www.regulations.gov in docket EPA-HQ-OPP-2012-0339. Below is a summary of the issues 

relevant to this registration review case.

Comments Received on the Preliminary Work Plan

The Agency received no comments during the public comment period on the initial docket. In 

the PWP, the Agency solicited comments on specific topics: environmental justice, water body 

impairment, trade irritants, and structure activity relationships. No comments or information 

were received during the public comment period concerning these issues. 

Note that on June 27, 2012, EPA announced certain revisions in harmonized guideline series 850 

- Ecological Effects Tests - including removal of the Tier designation on 850.5400 (Algal 

Toxicity). For more information see "Final Test Guidelines; OCSPP 850 Series; Notice of 

Availability" 77 FR 38282, June 27, 2012. Based on these changes, the Algal Toxicity study 

(GLN 850.5400) anticipated as being required in the PWP has been replaced by the following 

harmonized guidelines: 

 850.4500: Algal Toxicity 

 850.4550: Cyanobacteria (Anabeana flos-aquae) Toxicity 

The work plan and timeline described in the PWP remain as they were presented initially. 

Further, this document makes final the work plan for the Nabam registration review process. 

Risk Assessments and Anticipated Data Needs

The Agency will conduct a comprehensive ecological risk assessment, including an endangered 

species risk assessment, for all uses of Nabam. The Agency will conduct a human health risk 

assessment. The Agency expects to require additional data for use in conducting the registration 

review for Nabam. 

Ecological Risk Assessment Status and Anticipated Data Needs 

 The most recent quantitative ecological risk assessment for nabam was completed in support 

of the 1996 RED. 

 The Agency has not conducted a risk assessment that supports a complete endangered 

species determination for Nabam. The ecological risk assessment planned during registration 

review will allow the Agency to determine whether Nabam’s use has 'no effect' or 'may 

affect' federally listed threatened or endangered species (listed species) or their designated 

critical habitats. When an assessment concludes that a pesticide’s use 'may affect' a listed 

species or its designated critical habitat, the Agency will consult with the U.S. Fish and 

Wildlife Service and/or National Marine Fisheries Services (the Services), as appropriate. 
Docket Number: EPA-HQ-OPP-2012-0339 

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 Paper and paperboard mills and sugar beet/cane processing facilities are associated with a 

major waste water discharge that have the potential to contaminate drinking water for 

consumption by humans and livestock. As a result, nabam and/or ethylene thiourea (ETU) – 

the most stable, toxic and mobile degradate of nabam – could potentially pass through waste 

water treatment plants (WWTPs). 

 The Agency anticipates the need to require the following additional ecological data for use in 

conducting the registration review of Nabam. 

 850.4500: Algal Toxicity1

850.4550: Cyanobacteria (Anabeana flos-aquae) Toxicity1 

850.1400 -- Fish early-life stage toxicity test (freshwater) 

850.1450 -- Fish early-life stage toxicity test (saltwater) 

 The Agency anticipates the need to require the following additional environmental fate data 

for use in conducting the registration review of Nabam. 

850.6800 -- Activated sludge, respiration inhibition test2 

835.3110 -- Ready Biodegradability2

835.3220 -- Porous Pot Test2

835.3280 -- Simulation Tests to Assess the Biodegradability of Chemicals Discharged 

to Wastewater2 

835.3240 -- Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units2

For more information, please refer to Product Chemistry, Environmental Fate, and Ecological 

Effects Scoping Document in Support of Registration Review of Nabam, located in the docket. 

Human Health Risk Assessment Status and Anticipated Data Needs 

 The most recent human health risk assessment for nabam was performed to support the 1996 

RED. 

 

1

 Results for studies conducted with nabam and ETU for (i) the freshwater green alga, Selenastrum capricornutum, 

(ii) the freshwater diatom, Navicula pelliculosa, (iii) the marine diatom, Skeletonema costatum, and (iv) the 

cyanobacteria species Anabaena flos-aquae, must be submitted to satisfy this requirement. Final 850 guidelines for 

the algal testing were posted in June 2012. The Public Draft OPPTS 850.5400 Algal Toxicity guideline was split 

into two separate guidelines and renumbered with the cyanobacteria species separated into OCSPP 850.4550 and the 

other three species under OCSPP 850.4500. 

2

 The results of the Activated Sludge Respiration Inhibition Test (ASRI) will determine which of these four 

biodegradation tests is/are required. If the ASRI test EC50 is less than or equal to 20 mg/L, then either the 

(i)Biodegradation in Activated Sludge Study or (ii) Simulation Test – Aerobic Sewage Treatment: A. Activated 

Sludge Units or (iii) the Porous Pot Test is required. If the ASRI test EC50 is greater than 20 mg/L, then the 

registrant must conduct either: (i) Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge or b) 

Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units or c) the Porous Pot Test. If the Ready 

Biodegradability study is conducted and passes, then no further testing is required. If, however, the antimicrobial 

fails the Ready Biodegradability study, then the a) Biodegradation in Activated Sludge or b) Simulation Test – 

Aerobic Sewage Treatment: A. Activated Sludge Units, or c) the Porous Pot study is required 
Docket Number: EPA-HQ-OPP-2012-0339 

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Dietary Assessment

 Registered nabam uses that could potentially result in residues in food are use as a slimicide 

in the pulp slurry of paper mills and in beet and cane sugar extraction water. Most labels state 

that treated paper and paperboard may be used for food packaging. FDA has deemed the 

indirect food additive use of nabam safe when used as a slimicide in paper/paperboard 

production with no maximum treatment concentration specified (21 CFR 176.300). FDA has 

also deemed the secondary direct food additive use of nabam safe when used as an 

antimicrobial in sugar production at 3 ppm expressed in terms of the raw sugar beets or 

sugarcane [21 CFR 173.320(b)(2) and –(3)]. 

Tolerances and International Harmonization

 There are no pesticide tolerances or exemptions from the requirement of tolerances for 

nabam under the jurisdiction of EPA. Nabam is, however, cleared by the Food and Drug 

Administration (FDA) as an indirect food additive and formulated due to its use in sugar mill 

grinding, crusher, and/or diffuser systems (21 CFR 173.320(b)(3) at levels less than or equal 

to 3.0 ppm on raw sugar cane or sugar beets. 

Occupational and Residential Assessment and Risk

 The Agency conducted an occupational and residential exposure assessment for the RED in 

1996 (D208114, D215335). The RED imposed mitigation requirements that stipulated that 

“all products must be loaded and transferred only using a metering-pump system or a closed 

loading/application system.” All the existing labels now have language that specifies 

metering pumps or closed loading systems and occupational handler and postapplication 

exposures are minimized. As a result, the Agency does not anticipate the need to develop 

occupational handler and/or postapplication assessments for registration review. 

 For nabam there is no potential exposure to residential handlers. Therefore, residential risk 

assessments are not required. Nabam registered products contain the label statement for 

"industrial use only" and are, therefore, intended for occupational use. None of the registered 

nabam uses are likely to involve direct applications at residential sites; therefore, the Agency 

will not need to develop nabam residential handler and/or residential postapplication 

assessments for registration review 

Aggregate and Cumulative Exposure and Risk

 In examining aggregate exposure, EPA takes into account the available and reliable 

information concerning exposures to pesticide residues in food and drinking water, and nonoccupational pesticide exposures. Dietary (food and drinking water) exposures of concern are 

anticipated for nabam and ETU. Residential exposures are not of concern. An aggregate risk 

assessment for nabam as well as ETU is needed to assess aggregate exposures from food and 

drinking water. 
Docket Number: EPA-HQ-OPP-2012-0339 

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 EPA does not have, at this time, available data to determine whether Nabam has a common 

mechanism of toxicity with other substances or how to include this pesticide in a cumulative 

risk assessment. 

 For the purposes of this Registration Review, EPA has assumed that Nabam does not have a 

common mechanism of toxicity with other substances when used as an antimicrobial as 

registered. 

Human Health Anticipated Data Needs

 The Agency anticipates the need to require the following additional human health data for 

use in conducting the registration review of Nabam. 

860.1520 -- Processed food/feed 

Special Study -- Migration Study3

Special Study -- Nature of Residue in Paper3

For more information, please refer to Nabam: Human Health Risk Assessment Scoping 

Document in Support of Registration Review, located in the docket. 

Product Chemistry Anticipated Data Needs

 The Agency does not anticipate the need to require additional product chemistry data for the 

registration review at this time. 

For more information, please refer to Product Chemistry, Environmental Fate, and Ecological 

Effects Scoping Document in Support of Registration Review of Nabam, located in the docket. 

Incidents:

Ecological: 

 No Nabam ecological incidents have been reported in the Agency's Ecological Incident 

Information System (EIIS). 

Human Health: 

 No Nabam human poisoning incidents have been reported in the Agency's Incident Data 

System (IDS). 

 

3

 The anticipated DCI will provide that a protocol must be submitted for review and approval by the Agency prior to 

initiating this study. 
Docket Number: EPA-HQ-OPP-2012-0339 

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Endangered Species 

The Agency has not conducted a risk assessment that supports a complete endangered species 

determination for Nabam. The ecological risk assessment planned during registration review will 

allow the Agency to determine whether Nabam’s use has 'no effect' or 'may affect' federally 

listed threatened or endangered species (listed species) or their designated critical habitats. When 

an assessment concludes that a pesticide’s use 'may affect' a listed species or its designated 

critical habitat, the Agency will consult with the U.S. Fish and Wildlife Service and/or National 

Marine Fisheries Services (the Services), as appropriate. 

Endocrine Disruptor Screening Program 

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse 

outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and 

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, 

reproductive, and general or systemic toxicity. These studies include endpoints which may be 

susceptible to endocrine influence, including effects on endocrine target organ histopathology, 

organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, 

and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and 

chronic studies that assess growth, developmental and reproductive effects in different 

taxonomic groups. As part of its 1996 reregistration eligibility decision for nabam, EPA 

reviewed these data and selected the most sensitive endpoints for relevant risk assessment 

scenarios from the existing hazard database. However, as required by FFDCA section 408(p), 

Nabam is subject to the endocrine screening part of the Endocrine Disruptor Screening Program 

(EDSP). 

EPA has developed the EDSP to determine whether certain substances (including pesticide 

active and other ingredients) may have an effect in humans or wildlife similar to an effect 

produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator 

may designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine-related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 

2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, 

which contains 58 pesticide active ingredients and 9 inert ingredients. Nabam is not among the 

group of 58 pesticide active ingredients on the initial list to be screened under the EDSP. 

Accordingly, as part of registration review, EPA will issue future EDSP orders/data call-ins, 

requiring the submission of EDSP screening assays for Nabam. For further information on the 

status of the EDSP, the policies and procedures, the list of 67 chemicals, future lists, the test 

guidelines and the Tier 1 screening battery, please visit our website: http://www.epa.gov/endo/. 
Docket Number: EPA-HQ-OPP-2012-0339 

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Timeline

EPA has created the following estimated timeline for the completion of the Nabam registration 

review: 

Anticipated Schedule

Activities Estimated Month/Year

Phase 1: Opening the docket 

Open Public Comment Period for Docket Completed 

July 2012

Close Public Comment Period for Docket Completed 

September 2012 

Phase 2: Case Development 

Develop Final Work Plan (FWP) Completed 

December 2012 

Issue DCI December 2013 

Data Submission December 2015 

Open Public Comment Period for Preliminary Risk Assessments June 2017 

Close Public Comment Period for Preliminary Risk Assessments July 2017 

Phase 3: Registration Review Decision 

Open Public Comment Period for Proposed Reg. Review Decision December 2017 

Close Public Comment Period for Proposed Reg. Review Decision February 2018 

Final Decision and Begin Post-Decision Follow-up June 2018 

Total (years) 6 

Next Steps

A DCI will be developed regarding the data needs listed under the “Risk Assessments and 

Anticipated Data Needs” section of this document. The Agency expects to issue the DCI in 

December 2013. Human health and environmental fate and ecological hazard assessments will 

be conducted for all uses. 

 
Docket Number: EPA-HQ-OPP-2012-0339 

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Summary of Anticipated Data Requirements – Nabam 

The table below summarizes anticipated data needs for the Nabam Case in this document (Final 

Work Plan), Product Chemistry, Environmental Fate, and Ecological Effects Scoping Document 

in Support of Registration Review of Nabam, and Nabam: Human Health Risk Assessment 

Scoping Document in Support of Registration Review. 

Guideline 

Number Anticipated Data Requirement Test Material 

Estimated Timeframe 

(Measured in months from DCI 

Receipt) 

 850.45004 Algal Toxicity TGAI and 

ETU 12 

 850.45504 Cyanobacteria (Anabeana flos-aquae) Toxicity TGAI and 

ETU 12 

 850.1400 Fish early-life stage toxicity test ETU 12 

 850.33005 Modified activated sludge, respiration 

inhibition test ETU 12 

 835.31105 Ready Biodegradability TGAI 12 

 835.32205 Porous Pot Test TGAI 12 

 835.32805

Simulation Tests to Assess the 

Biodegradability of Chemicals Discharged to 

Wastewater

TGAI 12 

 835.32405 Simulation Test – Aerobic Sewage Treatment: 

A. Activated Sludge Units TGAI 12 

 860.1520 Processed food/feed TGAI 24 

 Special Study6 Nature of Residue in Paper TGAI 24 

 Special Study6 Migration Study TGAI 24 

 

4

 Results for studies conducted with nabam and ETU for (i) the freshwater green alga, Selenastrum capricornutum, 

(ii) the freshwater diatom, Navicula pelliculosa, (iii) the marine diatom, Skeletonema costatum, and (iv) the 

cyanobacteria species Anabaena flos-aquae, must be submitted to satisfy this requirement. Final 850 guidelines for 

the algal testing were posted in June 2012. The Public Draft OPPTS 850.5400 Algal Toxicity guideline was split 

into two separate guidelines and renumbered with the cyanobacteria species separated into OCSPP 850.4550 and the 

other three species under OCSPP 850.4500. 

5

 The results of the Activated Sludge Respiration Inhibition Test (ASRI) expected to be required will determine 

which of these three biodegradation tests would be anticipated to be required. If the ASRI test EC50 is less than or 

equal to 20 mg/L, then either the Biodegradation in Activated Sludge Study or Simulation Test – Aerobic Sewage 

Treatment: A. Activated Sludge Units or the Porous Pot Test would be anticipated to be required. If the ASRI test 

EC50 is greater than 20 mg/L, then the DCI expected to be issued would provide that the registrant would choose to 

conduct either: (i) Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge or b) Simulation Test – 

Aerobic Sewage Treatment: A. Activated Sludge Units or c) the Porous Pot Test. If the Ready Biodegradability 

study is conducted and passes, then no further testing would be expected to be required. If, however, the 

antimicrobial fails the Ready Biodegradability study, then the Biodegradation in Activated Sludge or Simulation 

Test – Aerobic Sewage Treatment: A. Activated Sludge Units, or the Porous Pot study would be expected to be 

required. 

6

 The anticipated DCI will provide that a protocol must be submitted for review and approval by the Agency prior to 

initiating this study.