Docket Number; EPA–HQ–OPP–2009–0723 

www.regulations.gov 

 

United States Chemical Safety June 2010 

Environmental Protection and Pollution Prevention 

Agency (7510P)

Disodium Cyanodithioimidocarbonate 

(DCDIC) Final Work Plan 

Registration Review June 2010 

Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

3

TABLE OF CONTENTS

Disodium Cyanodithioimidocarbonate (DCDIC) Registration Review Team......................... 4

I. INTRODUCTION ..................................................................................................................... 5

II. COMMENTS RECEIVED ON THE PRELIMINARY WORK PLAN.............................. 5

III. RISK ASSESSMENT AND DATA NEEDS......................................................................... 6

IV. TIMELINE ............................................................................................................................ 13

V. GLOSSARY of TERMS & ABBREVIATIONS.................................................................. 14
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

4

Disodium Cyanodithioimidocarbonate (DCDIC) Registration Review Team

Human Health & Environmental Effects 

Nathan Mottl 

Srinivas Gowda 

Risk Management

Monisha Harris 

Lance Wormell 

Office of General Counsel

Philip Ross 
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

5

I. INTRODUCTION 

This is the Environmental Protection Agency’s (EPA or “the Agency”) Final 

Work Plan (FWP) for the registration review of Disodium Cyanodithioimidocarbonate 

(DCDIC). 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 DCDIC 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 DCDIC Preliminary Work Plan was published December 16, 2009. The 90-day 

comment period ended on March 16, 2010. The Preliminary Work Plan document is 

available on www.regulations.gov, docket number EPA-HQ-OPP-2009-0723. 

 

II. COMMENTS RECEIVED ON THE PRELIMINARY WORK PLAN 

 EPA received one comment during the public comment period on the initial 

docket, described below. In the PWP, EPA also solicited comments on three specific 

topics: environmental justice; water body impairment; and trade irritants. No comments 

or information were received during the public comment period concerning these issues. 

During the public comment period, EPA received one comment as described and 

discussed below. The comment received during the initial public comment period did not 

affect the data needs, work plan and timeline described in the PWP and they remain as 

they were presented initially in the PWP. Further, this document makes final the work 

plan for the DCDIC registration review process. 

Comment: The FIFRA Endangered Species Task Force (FESTF) submitted a 

comment requesting that any technical registrant for DCDIC who is not a member 

of the FESTF (or a company having met its data compensation obligations) be 

asked to provide a formal offer-to-pay to FESTF for reliance on their data. 
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

6

Response: The Agency thanks FESTF for its comment and will consider this 

information as it conducts the registration review and makes its registration 

review decisions. 

III. RISK ASSESSMENT AND DATA NEEDS 

A Reregistration Eligibility Decision was completed for DCDIC in September 

1994. However, to complete registration review, additional data are anticipated to be 

needed to conduct the human health and ecological risk assessments. 

Human Health Risk 

The hazard and exposure databases and the available risk assessments for DCDIC 

were examined to determine whether they reflect the current state of the science, 

changing use patterns, and current policies/regulations/statutory requirements. Based on 

its review, the Agency anticipates that additional toxicity and exposure studies will be 

needed for registration review. The EPA anticipates that there is potential occupational 

inhalation and dermal exposure through open-pour mixing/loading exposures. The 

Agency will need to select dermal and inhalation toxicity endpoints to conduct inhalation 

and dermal occupational handler risk assessments. The Agency believes that risk 

assessments are needed to ensure that the DCDIC registration review case meets the 

standards established by FIFRA and FFDCA, as amended by FQPA. 

The Agency anticipates needing to conduct a dietary assessment based on indirect 

dietary exposure. The need for drinking water assessment will be determined based on 

the environmental assessment. The 

 data, outlined in the anticipated environmental fate 

data needs, will be useful in determining whether discharged DCDIC resulting from the 

recirculating cooling tower use can pass through waste-water treatment facilities into 

drinking water or migrate into residential groundwater wells. 

The Agency has reached the following conclusions after reviewing the hazard and 

exposure databases. 

• The Agency believes the existing toxicological data triggers the need for an 

inhalation and dermal occupational risk assessment from exposure to open-pour 

mixing/loading systems. 

• An inhalation toxicity study is expected to be needed to assess inhalation 

occupational exposure. 

• Dermal and inhalation exposure studies are expected to be needed to assess 

occupational exposure. 

• The Agency will need to assess dietary exposures and risks for food use sites 

(e.g., cane and beet sugar mills) and an indirect food use (e.g., preserved food 

paperboard). 

• Based on the need to assess dietary exposure, EPA anticipates that there will be a 

need for additional toxicity studies in order to characterize the hazards and select 
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

7

an oral toxicological endpoint (e.g., reproduction and fertility toxicity study and a 

90-day oral toxicity study in rodents). 

• The Agency expects to require environmental fate data (e.g., ready 

biodegradability test, photodegradation, etc.) for use in determining if discharged 

DCDIC resulting from the re-circulating cooling tower use can pass through 

waste-water treatment facilities into drinking water or migrate into residential 

groundwater wells. Therefore, the need for a dietary drinking water assessment 

would be determined upon submission and review of the environmental fate data. 

Further information is available in the document titled, “Disodium 

Cyanodithioimidocarbonate. Human Health Effects Scoping Document for the 

Registration Review Decision,” dated December 7,2009.

Dietary and Drinking Water Assessment

Dietary Exposure 

A dietary exposure risk assessment has not been performed for DCDIC. Because 

current labels indicate that raw juice and wash water for cane and beet sugar mills could 

be treated with DCDIC to prevent juice from spoiling and because DCDIC is used in pulp 

and papermills as a slimicide making it possible for DCDIC to migrate into food exposed

to the treated paper, the Agency will need to conduct a dietary assessment. 

DCDIC has been cleared for use by the Food and Drug Administration (FDA) for 

the use in sugar beet and sugar cane mills under 21 CFR 173.320. FDA limits DCDIC as 

a chemical for controlling microorganism in cane-sugar and beet-sugar mills to a 

maximum level of 2.5 ppm in terms of the weight of the raw cane or raw beet. DCDIC 

has been cleared for use by the FDA for food contact with food grade paper, paperboard, 

(21 CFR 176.300), adhesives (21 CFR 175.105), animal glue (21 CFR 178.3120) and 

manufacture of paper and paperboard products used in food packaging (21 CFR 181.30). 

Drinking Water Exposure 

The need for a dietary drinking water assessment will be determined upon 

submission and review of the environmental fate data expected to be required. DCDIC is 

primarily used in indoor industrial use sites (e.g., industrial water purification systems, 

sugar and cane processing water, and recirculating water cooling towers). The current 

indoor uses of DCDIC are expected to result in minimal residues in drinking water 

supplied by residential wells or municipal sources because re-circulating water cooling 

towers are expected to have infrequent discharges and the discharges are regulated by 

NPDES permits. In addition, labels specify that the industrial water purification systems 

are not intended for use in potable water systems. 

However, the need for a dietary drinking water exposure assessment for DCDIC 

will be determined upon review of environmental fate data expected to be required. The 

environmental fate data would be useful in determining the likelihood of discharged 
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

8

DCDIC resulting from the re-circulating cooling tower use passing through waste-water 

treatment facilities into drinking water or migrating into residential groundwater wells. 

Although the oil well injection use is an outdoor industrial use, EPA expects that 

DCDIC would be contained within a well casing when it is used, and that ground water is not 

normally at risk of contamination under these conditions. Therefore, EPA will not conduct 

any drinking water assessments for this particular use. 

Tolerances

There are no tolerances or exemptions from tolerances for DCDIC. DCDIC is 

allowed as a secondary direct food additive at a maximum level of 2.5 ppm (expressed as 

weight of the raw cane or raw beet) for controlling microorganisms in cane-sugar and 

beet-sugar mills by the Food and Drug Administration (FDA) under 21 CFR 173.320. 

DCDIC is used as a slimicide in the manufacture of food grade paper and paperboard (21 

CFR 176.300), as a component of adhesives (21 CFR 175.105), in the production of 

animal glue (21 CFR 178.3120) and in manufacture of paper and paperboard products 

used in food packaging (21 CFR 181.30). 

It is noted that exemptions and regulations for food additives under Section 409 of 

the Federal Food, Drug, and Cosmetic Act (FFDCA) do not relieve the registrant of 

meeting the standard under Section 408 as amended by the Food Quality Protection Act 

(FQPA), when the active ingredient is subject to regulation as a food-use pesticide under 

the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Under Section 408, a 

determination of safety for residues of a pesticide that may be in food is required, and as 

defined in Section 408(b)(2)(ii), “that there is a reasonable certainty that no harm will 

result from aggregate exposure to the pesticide chemical residue, including all anticipated 

dietary exposures and all other exposures for which there is reliable information.” Use of 

DCDIC in food contact articles is interpreted as a food use. Therefore, a dietary risk 

assessment will be needed to determine if there are any potential dietary concerns from 

indirect food exposures to DCDIC. EPA will perform a risk assessment to determine if 

tolerances or exemptions from tolerances will be needed to support the existing registered 

uses of DCDIC. 

Aggregate and Cumulative Exposure

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

reliable information concerning exposures to pesticide residues in food and drinking 

water, as well as non-occupational pesticide exposures. An aggregate assessment is 

needed and expected to be comprised of human exposures to DCDIC derived from 

dietary exposure (food), depending on the outcome of the needed environmental fate and 

exposure studies. The aggregate assessment may include dietary exposure (drinking 

water) and/or residential exposure to be determined during the risk assessment stage of 

this Registration Review. 

Section 408(b)(2)(D)(v) of FFDCA requires that, when considering whether to 

establish, modify, or revoke a tolerance, the Agency consider "available information” 
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

9

concerning the cumulative effects of a particular pesticide's residues and "other 

substances that have a common mechanism of toxicity.” EPA has not yet determined 

whether DCDIC has a common mechanism with other compounds; consequently, a 

cumulative assessment will not be performed at this time. 

Occupational and Residential Assessment

An occupational and/or residential exposure assessment is required for an active 

ingredient if (1) certain toxicological criteria are triggered and (2) there is potential 

exposure to handlers (mixers, loaders, applicators, etc.) during use or to persons entering 

treated sites after application is complete. The Agency believes the existing toxicological 

data trigger the need for an inhalation and dermal occupational risk assessment based on 

potential exposure from open-pour mixing/loading systems. 

The additional occupational exposure guideline studies anticipated to be needed to 

conduct an inhalation and dermal occupational risk assessment from exposures from 

open-pour mixing/loading scenarios (pulp and paper, recirculation cooling towers, and 

petroleum secondary recovery operations), include: 

o (GLN 875.1200) Dermal Indoor Exposure; 

o (GLN 875.1400) Inhalation Indoor Exposure; 

o (GLN 875.1600) Data Reporting and Calculations; and, 

o (GLN 875.1700) Product Use Information 

Based on review of the current DCDIC end-use, the Agency anticipated that there 

will be no residential exposures; a residential handler assessment will not be needed. 

Because of low vapor pressure <9.16 x 10-6 torr at 25oC and dilution rates of end use 

products, occupational post-application and residential post-application exposures are 

expected to be negligible and these particular risk assessments are not needed. 

It should be noted that one active formulating product label cites a paint use. The 

Agency was not able to identify an application rate for this paint use on the formulating 

product label and was not able to determine how this product is to be used. Without an 

application rate, product use, or valid exposure studies, the Agency can not adequately 

assess the paint use. The registrant would need to submit data to support the paint uses, so 

the Agency could develop occupational and residential assessments to determine if the 

paint uses are a risk concern to occupational workers and residential homeowners. 

As a result the Agency would anticipate needing specific occupational and 

residential occupational handler studies to support the paint uses in registration review. 

The Agency anticipates that the data needed to support the paint use would include the 

following studies: 

o (GLN 875.1200) Dermal Indoor Exposure (airless painting and paint brush 

applicator exposure) 
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

10

o (GLN 875.1400) Inhalation Indoor Exposure (airless painting and paint brush 

applicator exposure) 

o (GLN 875.1600) Data Reporting and Calculations 

o (GLN 875.1700) Product Use Information 

Anticipated Human Health Data Needs 

The Agency anticipates needing the following toxicity and exposure studies to 

assess the DCDIC registration review case: 

Toxicity Data Needs 

o (GLN 870.3465) 90-day Inhalation Toxicity Study 

o (GLN 870.3100) 90-day Oral Toxicity- Rodent 

o (GLN 870.3800) Reproduction and Fertility Effects 

Occupational Handler Exposure Data Needs 

o (GLN 875.1200) Dermal Indoor Exposure 

o (GLN 875.1400) Inhalation Indoor Exposure 

o (GLN 875.1600) Data Reporting and Calculations 

o (GLN 875.1700) Product Use Information 

Further information is available in the document titled, “Disodium 

Cyanodithioimidocarbonate. Human Health Effects Scoping Document for the 

Registration Review Decision,” dated December 7, 2009. 

Environmental Fate and Ecological Risk Assessment Status and Data Needs

The Agency reviewed the environmental fate and ecological hazard databases for 

DCDIC. Based on its review, EPA believes risk assessments are needed to ensure that the 

DCDIC registration review case meets the FIFRA standards. The Agency will complete 

the environmental fate and ecological hazard risk assessments presented below. 

Further information is available in the document titled, “Summary of Product 

Chemistry, Environmental Fate, and Ecotoxicity Data for the Disodium 

Cyanodithioimidocarbonate Registration Review Decision Document,” dated December 

7, 2009. 

 Environmental fate and ecological risk assessments have not been conducted for 

DCDIC. The use of DCDIC as a materials preservative, and industrial slimicides used in 

recirculating water cooling towers and paper mills that potentially pass through waste 

water treatment plants (WWTPs) could potentially result in environmental exposure. 

Therefore, the Agency will conduct environmental fate and ecological risk assessments to 

assess environmental exposure. The Agency also anticipates that environmental fate and 

ecological data will be needed to conduct these assessments. 
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

11

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

endangered species determination for DCDIC. The ecological risk assessment planned 

during registration review will allow the Agency to determine whether use of DCDIC 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 

Service (the Services), as appropriate. 

Anticipated Environmental Fate and Ecological Data Needs 

The Agency has not conducted an environmental fate assessment for DCDIC. 

However, the Agency anticipates needing to conduct an environmental fate assessment 

for material preservatives, and industrial slimicides used in recirculating water cooling 

towers and paper mills that potentially pass through waste water treatment plants 

(WWTPs) and may be discharged into terrestrial and aquatic environments. 

The Agency anticipates needing the following data in order to conduct a complete 

environmental fate assessment: 

o (GLN 835.2120) 5-day hydrolysis study at 50oC in basic conditions; 

o (GLN 835.2240) photodegradation in water study; 

o (GLN 850.6800) modified activated sludge respiration inhibition; 

o (GLN 835.1110) activated sludge sorption isotherm; and 

o (GLN 835.3110) ready biodegradability. 

The Agency anticipates needing the following data in order to conduct a complete 

ecological risk assessment, including an endangered species assessment: 

o (GLN 850.5400) algal toxicity (Tier II) using freshwater green alga, 

Selenastrum capricornutum.

Anticipated Physical/Chemical Property Data Needs 

All product chemistry data requirements have been fulfilled; therefore, the 

Agency does not anticipate needing additional product chemistry data for DCIC.

Incidents 

One reported incident was identified in the OPP Incident database. An 

occupational worker developed a rash that required hospitalization after using a DCDIC 

product. The Agency notes that the product associated with the incident is no longer 

registered. 

Endocrine Disruptor Screening Program 
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

12

As required under FFDCA section 408(p), EPA has developed the Endocrine 

Disruptor Screening Program (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. 

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. This list of chemicals was selected based on the potential for human 

exposure through pathways such as food and water, residential activity, and certain postapplication agricultural scenarios. This list should not be construed as a list of known or 

likely endocrine disruptors. 

DCDIC is not among the group of 58 pesticide active ingredients on the initial list 

to be screened under the EDSP. Under FFDCA sec. 408(p) the Agency must screen all 

pesticide chemicals. Accordingly, EPA anticipates issuing future EDSP test orders/data 

call-ins for all pesticide active ingredients. 

For further information on the status of the EDSP, the policies and procedures, the 

list of 67 chemicals, the test guidelines and the Tier 1 screening battery, please visit our 

website: http://www.epa.gov/endo/. 
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

13

IV. TIMELINE 

The EPA has created the following estimated timeline for the completion of the 

DCDIC registration review case. The Agency anticipates requiring additional data and 

residential, occupational and ecological exposure assessments for this registration review 

case. 

Anticipated Schedule

Activities Estimated Month/Year 

Phase 1: Opening the docket 

Open Public Comment Period for DCDIC Docket Completed December 2009

Close Public Comment Period Completed March 2010 

Phase 2: Case Development 

Develop Final Work Plan (FWP) Completed June 2010 

Issue DCI June 2011 

Data Submission June 2013 

Open Public Comment Period for Preliminary Risk Assessments December 2014 

Close Public Comment Period March 2014 

Phase 3: Registration Review Decision 

Open Public Comment Period for Proposed Reg. Review Decision June 2015 

Close Public Comment Period September 2015 

Final Decision and Begin Post-Decision Follow-up 2015 

Total (years) 6 

Next Steps

The Agency plans to develop a Data Call-In for this pesticide and expects to issue 

it in June 2011. 
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

14

V. GLOSSARY of TERMS & ABBREVIATIONS

ai Active Ingredient 

AR Anticipated Residue 

ASTM American Society for Testing and Materials 

AWPA American Wood Preserver’s Association 

CBI Confidential Business Information 

CFR Code of Federal Regulations 

cPAD Chronic Population Adjusted Dose 

CSF Confidential Statement of Formula 

CSFII USDA Continuing Surveys for Food Intake by Individuals 

DCI Data Call-In 

DEEM Dietary Exposure Evaluation Model 

DFR Dislodgeable Foliar Residue 

DNT Developmental Neurotoxicity 

DWLOC Drinking Water Level of Comparison 

EC Emulsifiable Concentrate Formulation 

EDWC Estimated Drinking Water Concentration 

EEC Estimated Environmental Concentration 

EP End use Product 

EPA Environmental Protection Agency 

EUP End-Use Product 

FDA Food and Drug Administration 

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act 

FFDCA Federal Food, Drug, and Cosmetic Act 

FQPA Food Quality Protection Act 

FOB Functional Observation Battery 

GENEEC Tier I Surface Water Computer Model 

IR Index Reservoir 

LC50 Median Lethal Concentration. A statistically derived concentration of a 

substance that can be expected to cause death in 50% of test animals. It is 

usually expressed as the weight of substance per weight or volume of water, air 

or feed, e.g., mg/l, mg/kg or ppm. 

LD50 Median Lethal Dose. A statistically derived single dose that can be expected to 

cause death in 50% of the test animals when administered by the route indicated 

(oral, dermal, inhalation). It is expressed as a weight of substance per unit 

weight of animal, e.g., mg/kg. 

LOC Level of Concern 

LOAEL Lowest Observed Adverse Effect Level 

μg/g Micrograms Per Gram 

μg/L Micrograms Per Liter 

mg/kg/day Milligram Per Kilogram Per Day 

mg/L Milligrams Per Liter 

MOE Margin of Exposure 

MRID Master Record Identification (number). EPA's system of recording and tracking 

submitted studies. 

MUP Manufacturing-Use Product 

NA Not Applicable 

NAWQA USGS National Ambient Water Quality Assessment 

NPDES National Pollutant Discharge Elimination System 

NR Not Required 

NOAEL No Observed Adverse Effect Level 

OPP EPA Office of Pesticide Programs 

OPPTS EPA Office of Prevention, Pesticides and Toxic Substances 

PAD Population Adjusted Dose 
Docket Number; EPA-HQ-OPP-2009-0723 

www.regulations.gov 

15

PAIRA Pure Active Ingredient Radiolabelled 

PCA Percent Crop Area 

PDP USDA Pesticide Data Program 

PHED Pesticide Handler's Exposure Data 

PHI Preharvest Interval 

phr Pounds Per Hundred 

ppb Parts Per Billion 

PPE Personal Protective Equipment 

ppm Parts Per Million 

PRZM/EXAMS Tier II Surface Water Computer Model 

Q1* The Carcinogenic Potential of a Compound, Quantified by the EPA's Cancer 

Risk Model 

RAC Raw Agriculture Commodity 

RED Reregistration Eligibility Decision 

REI Restricted Entry Interval 

RfD Reference Dose 

RQ Risk Quotient 

RTU Ready to Use 

SCI-GROW Tier I Ground Water Computer Model 

SAP Science Advisory Panel 

SF Safety Factor 

SLN Special Local Need (Registrations Under Section 24©) of FIFRA) 

TGAI Technical Grade Active Ingredient 

TEP Typical End-Use Product 

USDA United States Department of Agriculture 

UF Uncertainty Factor 

WPS Worker Protection Standard