Docket Number EPA-HQ-OPP-2015-0348 

www.regulations.gov 

Pentachloronitrobenzene Preliminary Work Plan 

Registration Review: Initial Docket 

Case Number 0128 

Approved by: 

Date: 

March 2016 

Yu-Tin Guilaran, Director 

Pesticide Re-evaluation Division 
Pentachloronitrobenzene (PCNB) Preliminary Work Plan- Table of Contents 

OVERVIEW ................................................................................................................................... 4 

ANTICIPATED DATA NEEDS ................................... ................................................................. 5 

STATUTORY AND REGULATORY AUTHORITY .................................................................. . 7 

CHEMICAL FACTS ...................................................................................................................... 8 

USE AND USAGE INFORMATION ......................................................... ................................... 9 

RECENT ACTIONS ..................................................................................................................... 10 

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW .......... .................... 10 

TIME LINE .................................................................................................................................... 12 

NEXT STEPS ............................................................................................................................... 13 

Appendix - Additional Areas Considered in the PCNB Registration Review ......................... 14 

References: 

This Preliminary Work Plan summarizes the Environmental Protection Agency's current position 

based on the following documents: 

1. Registration Review: Preliminary Problem Formulation for Environmental Fate 

Ecological Risk, Endangered Species, and Human Health Drinking Water Exposure 

Assessments for Pentachloronitrobenzene (PCNB). Jim Carleton, Ph.D., and Thomas 

Steeger, Ph.D. March 6, 2016. 

2. Pentachloronitrobenzene (PCNB). Human Health Assessment Scoping Document in 

Support of Registration Review. Shalu Shelat, Julie L. Van Alstine, and Evisabel Craig. 

March 11 , 2016. 

3. Pentachloronitrobenzene (PCNB): Tier I (Scoping) Review of Human Incidents. 

Elizabeth Evans and Sharma Recore. March 2, 2016. 

2 
4. BEAD Chemical Profile (BCP) for Registration Review of PCNB 

(Pentachloronitrobenzene), Chemical Code 056502. Leonard Yourman, Rafael A. Prieto, 

and Andrew Lee. December 24,2015. 

5. PCNB (056502) Screening Level Usage Analysis (SLUA). June 26, 2015. 

6. Label Data Report Spreadsheet: PC Code: 056502. July 23, 2015. 

7. Health Effects Division Master Label Report Spreadsheet: PC Code 056502. July 23, 

2015. 

These and other supporting documents for the PCNB registration review case may be found in 

the docket EPA-HQ-OPP-2015-0348 at http://www.regulations.gov. 

3 
OVERVIEW 

The docket for pentachloronitrobenzene (PCNB) is now open, initiating the first public comment 

period for this registration review (docket number EPA-HQ-OPP-20 15-0348). 

Pentachlorobenzene (PCNB) is an organochlorine contact fungicide registered for the control of 

fungal diseases on agricultural crops such as beans, broccoli, Brussels sprouts, cabbage, 

cauliflower, collards, cotton, garlic, kale, mustard, peanuts, pepper, potato, and tomato. PCNB is 

also registered for non-agricultural uses such as golf courses, ornamental plants, bulbs, turf and 

professional and college athletic fields. In addition, over 80 metabolites/degradates of PCNB 

have been identified. Three are considered to be "major degradates"-- pentachloroanaline 

(PCA), pentachlorothioanisole (PCTA) and pentachlorobenzene (PCB). These compounds also 

are of potential concern from an ecotoxicological perspective. Of the three, PCA is of the 

greatest significance due to its stability and mobility, and its relatively high concentration in fate 

studies for PCNB (up to 86.6% of applied radioactivity). PCTA is less mobile, and PCP 

appeared in only one fate study. The Agency intends to require several fate and ecotoxicity 

studies on the PCA degradate only, to address its environmental fate characteristics and relative 

abundance in the fate studies. 

This Preliminary Work Plan (PWP) document explains what EPA's Office of Pesticide Programs 

knows about PCNB, highlighting anticipated data and assessment needs, identifying the types of 

information that would be especially useful to the Agency in conducting the review, and 

providing an anticipated timeline for completing the registration review for PCNB. 

The registration review process was designed to include a public participation component to 

solicit input from interested stakeholders. The Agency intends, by sharing this information in the 

docket, to inform the public of what it knows about PCNB and what types of new data or other 

information would be helpful for the Agency to receive as it moves toward a decision on PCNB. 

The Agency encourages all interested stakeholders to review the PWP and Appendix and to 

provide comments and additional information that will help the Agency's decision-making 

process for this chemical. In addition to general areas on which persons may wish to comment, 

there are some areas identified in the PWP and Appendix about which the Agency specifically 

seeks comments and information. Interested stakeholders could include: environmental nonprofit or interest groups; pesticide manufacturers; agricultural labor or commodity groups; 

commercial, institutional, residential, and other users of pesticides; or the public at large. 

The Preliminary Work Plan begins by listing the anticipated data needs for PCNB. Next, it 

discusses the statutory and regulatory authority for registration review. Then the document 

provides chemical facts, use and usage information, recent actions, the anticipated risk 

assessments, and a projected registration review timeline for PCNB. Finally, the Appendix to 

this document includes identification and discussion of some areas that are considered generally 

in registration review along with some additional chemical case-specific information. 

4 
ANTICIPATED DATA NEEDS 

Table 1 below summarizes anticipated data needs for PCNB. For additional discussion of the 

anticipated data needs, see the Registration Review: Preliminary Problem Formulation for 

Environmental Fate, Ecological Risk, Endangered Species, and Human Health Drinking Water 

Exposure Assessments for Pentachlorobenzene (PCNB) and Pentachloronitrobenzene (PCNB). 

Human Health Assessment Scoping Document in Support of Registration Review. 

Table 1: Anticipated Data Needs for the PCNB Registration Review 

Estimated 

Guideline Timeframe 

Number1 Study Title 

Test Material (Months from 

receipt of DCI) 

Anticipated Data Needs for the Parent PCNB 

835.2240 Photodegradation in Water TGAI 12 

835.2370 Photodegradation in Air TGAI 12 

835.4100 Aerobic Soil Metabolism TGAI 24 

835.4200 Anaerobic Soil Metabolism TGAI 24 

835.4300 Aerobic Aquatic Metabolism TGAI 24 

835.4400 Anaerobic Aquatic Metabolism TGAI 12 

850.1350 Aquatic invertebrate life cycle (saltwater) TGAI 12 

850. 1400 Fish early-life stage toxicity (saltwater) TGAI 12 

850.1500 Fish life cycle (freshwater)2 TGAI 24 

850.1500 Fish life cyc le (estuarine/marine) TGAI 24 

850.1735 Who le sediment: acute freshwater invertebrates TGAI 12 (3 benthic species) 

850.1740 Whole sediment: acute marine invertebrates (3 TGAI 12 benthic species) 

850.1850 Aquatic food chain transfer TGAI 12 

850.2100 Avian oral toxicity (passerine spec ies) TGAI 12 

850.3040 Field testing for pollinators (Tier Hl)

3 TEP 24 

850.4 100 Seedling emergence (Tier I/Tier II) TEP 12 

850.4150 Vegetative vigor (Tier 1/Tier II) TEP 12 

850.4550 Cyanobacteria (Anabaena flos-aquae) Toxicity TGAI 12 

850.4400 Aquatic plant growth (Lemna minor) Toxicity TGAI 12 

850.5400 Aquatic plant growth (Algal) Toxicity TGAI 12 

1 On June 27,2012, EPA announced certain revisions in harmonized guideline series 850 - Ecological Effects Tests 

-including renumbering and other designations or changes for some guideline studies. See "Final Test Guide lines; 

OCSPP 850 Series; Notice of Availability" 77 FR 38282, June 27, 2012. 

http://www.regulations.gov/#!documentDetaii;D=EPA-HQ-OPPT-2009-0 154-0028 2 The anticipated requirement may be waived if acceptable medaka extended one-generation data (OCSPP Guideline 

890.2200) are submitted. 3 For all Tier II and Tier III pollinator studies: the Agency anticipates requiring these studies pending the outcome 

of lower tier pollinator studies with larval and adult bees. 

5 
Table 1: Anticipated Data Needs for the PCNB Registration Review 

Estimated 

Guideline Study Title Timeframe 

Number1 Test Material (Months from 

receipt ofDCI) 

850.6100 Environmental chemistry methods & independent TGAI 12 laboratory validation (soil & sediment) 

850.6200 Environmental chemistry methods & independent TGAI 12 laboratory validation for water 

Non- Whole sed iment; chronic4 TGAI 12 

guideline 

Non- Acute oral toxicity test with adult honey bees TGAI 12 guideline (OECD 213)tTier I) 

Non- Acute honey bee larvae toxicity test (OECD 237) TGAI 12 guideline (Tier I) 

Non- 1 0-day adult honey bee chronic toxicity test (draft TGAI 12 guideline OECD test guideline) (Tier I) 

Non- 21-day larval honey bee chronic toxicity test TGAI 12 guideline (draft OECD guidance document) (Tier I) 

Non- Field trial of residues in pollen and necta~ (Tier TEP 12 guideline II) 

Non- Semi-field whole colony test (OECD 75)3 (Tier TEP 24 guideline II) 

860.1200 Directions for use5 TGAI 12 

860.13 00 Nature ofresidue-plants6

, livestock7 TGAI 24 

860.1340 Residue analytical methods-livestock TGAI 24 commodities8 

860.1 380 Storage stability data9 TEP 24 

860.1 480 Magnitude of the residue: meat/milk/poultry/eggs TGAI 24 

860.1 500 Magnitude of the residue: crop field trials 10 TEP 24 

4 A tiered testing strategy may be considered for the data recommended to be required for sediment toxicity. Under 

this strategy, I 0-day sediment toxicity testing is first conducted with Hyalella azteca, Chironomus dilutus, and 

Leptocheirus plumulosus under OSCPP Guidelines 850.1735 and 850.1740. After submission and review of data 

from these studies (including a comparison of estimated environmental concentrations in sediment and pore water 

with toxicity results from the I 0-day studies), the Agency will advise the registrant on the need for one or more 

chronic sediment toxicity studies. 

5 Labeling pertaining to rotational crops and feeding/grazing restrictions for some registrations is not supported with 

data; the Agency intends to require the relevant data (listed in this table). Alternatively, the registrant may elect to 

revise labels accordingly. Details on the labeling and supporting data may be found in Table A.8.1 in the scoping 

document. 

6 Potatoes or cabbage 7 Ruminant and poultry 8 Data are needed on levels of Total Radioactive Residue (TRR) for PCNB, PCA, and PCTA. 9 Data are needed to support Amvac's cottonseed, peanut, potato, and tomato processing studies. Storage stability 

data are also needed to support any new field trial and processing studies submitted for the registration review of 

PCNB. Details may be found in Table A.8.1 in the scoping document. 10 Potato, garlic, broccoli, beans, soybean (seed, forage and hay), peppers, tomatoes, cottonseed, and peanuts. 

6 
Table 1: Anticipated Data Needs for the PCNB Registration Review 

Estimated 

Guideline Study Title 

Timeframe 

Number1 Test Material (Months from 

receipt of DCI) 

860.1520 Magnitude of the residue: processed food/feed 11 TEP 24 

860.1900 Magnitude of the residue: field rotational crops TEP 24 

870.3465 90-day Inhalation - rat TGAI 24 

Non- Comparative thyroid assay TGAI guide line 12 

875.2 100 Dislodgeab1e foliar residue and turf transferab le 

TEP 24 

residues12 

No n- Foliar Dissipation13 (Guideline 835.6100 SS) TEP guide line 12 

Anticipated Data Needs for the Metabolite PCA 

835 .2240 Photodegradation in Water DEGR 12 

835.2370 Photodegradation in Air DEGR 12 

850.1 010 Acute toxicity fres hwater invertebrate DEGR 12 

850.1 025 

850.1 035 Acute toxicity estuarine and marine organisms DEGR 12 

850. 1045 (mysid) 

850.1 055 

850. 1075 Acute toxicity (saltwater fish) DEGR 12 

850. 1075 Acute toxicity freshwater fish bluegill sunfish DEGR 12 and rainbow trout 

850. 1300 Aquatic invertebrate life cycle (freshwater) DEGR 12 

850.1400 Fish early-life stage toxicity (freshwater) DEGR 12 

TGAI = techmcal grade active mgred1ent; TEP = typical end-use product; DEGR = degradate (PCA) 

STATUTORY AND REGULATORY AUTHORITY 

The Food Quality Protection Act (FQPA) of 1996 mandated a registration review program. All 

pesticides distributed or sold in the United States (U.S.) generally must be registered by the 

Environmental Protection Agency (EPA or the Agency), based on scientific data showing that 

they will not cause unreasonable risks to human health or the environment when used as directed 

on product labeling. 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 the statutory standard of no unreasonable adverse effects to human health or the 

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

11 A soybean processing study is needed. Alternatively, the registrant may elect to prohibit applications to soybean. 12 Dislodgeable foliar residue data only are anticipated to be required. 13 Foliar dissipation half-life data are needed to estimate residues on forage items for terrestrial wildlife. Residues 

and dissipation rates for the three major degradates (PCA, PCTA and PCB) and the minor degradates/contaminants 

(PCP and HCB) must be quantified. The Agency has used a default half-life value for foliar dissipation value for 

PCNB in its past assessments. The study should include relevant environmental chemistry methods (ECM) for soil, 

water, and sediment with independent laboratory validation (IL V). 

7 
Through the registration review program, the Agency periodically reevaluates pesticides to make 

sure that as change occurs, products in the marketplace can be used safely. Information on this 

program is provided on EPA's website. 14 

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. The regulations governing registration review begin at 40 CFR 15 5.40. The 

Agency will consider benefits information and data as required by FIFRA. The public phase of 

registration review begins when the initial docket is opened for each case. The docket is the 

Agency's opportunity to state what it knows about the pesticide and what additional risk analyses 

and data or information it believes are needed to make a registration review decision. After 

reviewing and responding to comments and data received in the docket during this initial 

comment period, the Agency will develop a Final Work Plan (FWP) and anticipated schedule for 

the registration review of PCNB. 

CHEMICAL FACTS 

Table 2 provides a summary of the chemical facts for PCNB. 

Table 2: Chemical Facts for PCNB. 

PC code 056502 

Case Number 0128 

CAS Number 82-68-8 

Year first registered June 30, 1964 

Pesticide Type Fungicide 

Chemical class Benzene; organochlorine 

Reregistration Eligibility RED was issued June 2006. 

Decision (RED) 

Tolerance Reassessment Not applicable. Tolerance reassessment was addressed in the 

Eligibility Decision RED. 

(TRED) 

Cumulative group Not applicable. PCNB has not been identified as a member of a 

cumulative group that shares a common mechanism of toxicity. 

40 CFR Citation Tolerances for PCNB are established in 40 CFR§180.291. 

Dual-use PCNB is registered for conventional pesticide uses only and has 

no registered antimicrobial or biopesticidal uses. 

Non-pesticidal uses There are no identified non-pesticidal uses of PCNB. 

Pesticide Re-evaluation Veronica Dutch, dutch.veronica@epa.gov, (703)-308-8585 

Division, Chemical 

Review Manager 

Registration Division, Hope Johnson, johnson.hope@epa.gov, (703)-305-5410 

Product Manager 

14http://www2.epa.gov/pesticide-reevaluation 

8 
USE AND USAGE INFORMATION 

Table 3 summarizes the use and usage information for PCNB. Please see the BEAD Chemical 

Profile (BCP) for Registration Review of PCNB (Pentachloronitrobenzene), Chemical Code 

056502 in the registration review docket for more details. 

Table 3: PCNB Use and Usage Information 

Summary of Use PCNB is a contact fungicide that is registered for preventative and 

residual protection against soil-borne fungal diseases on 

vegetables, field crops, turf, and ornamentals. PCNB' s mode of 

action has not been definitively characterized but is proposed to 

be through lipid peroxidation, causing cell damage 15

. PCNB has 

commonly been used in combination with insecticides and other 

fungicides. 

Use Sites Use sites for PCNB are beans, broccoli, Brussels sprouts, 

cabbage, cauliflower, collards, cotton, potato, garlic, kale, 

mustard, peanuts, pepper, and tomato, golf course turf grass such 

as tees, greens and fairways, and ornamental bulbs. 

Summary ofUsage Average agricultural usage (1998-2013) was approximately 

360,000 pounds of active ingredient applied annually on 

approximately 440,000 acres, for an overall average of 0.82 

pounds a.i./acre. Average usage for 2011 indicated that golf 

courses were the main non-agricultural use for PCNB at 250,000-

500,000 lbs/year. 

Formulation Type(s) PCNB is formulated as a granular, flowable concentrate, 

emulsifiable concentrate, and dry flowable. 

Application Method(s) Products can be applied as a foliar broadcast, soil band, soil 

drench, bulb dip, soil broadcast, in-furrow, and through 

chemigation. 

Technical Registrant(s) Amvac Chemical Company 

No. of Registrations 9 Section 3 products 16 

Restricted Use No 

Guidance for Commenters: Additional areas of use and usage related information 

requested for this registration review, and of particular interest to EPA, are described below. 

• If any label use parameters are missing, EPA expects to use conservative assumptions to 

approximate these parameters in order to conduct a quantitative risk 

assessment. However, the Agency will work with registrants to clarify information on 

PCNB product labels, especially the maximum annual application rates for nonagricultural uses including golf courses, turf, and ornamental lawns. 

• The Agency seeks information on seed treatment usage for PCNB. 

15 http://www.frac.info/home 16 Section 3 product labels can be obtained from the Pesticide Product Label System (PPLS) website 

(http:/ /oaspub.epa.gov/pestlabVppls.home ). 

9 
• The Agency seeks usage data for non-agricultural uses ofPCNB, including bulb dips and 

ornamental soil drenches. 

RECENT and PENDING ACTIONS 

A new end-use product containing PCNB was registered August 28, 2015, for use on golf course 

turf-greens, tees, and fairways only. 

Removal of conditions on technical AMV AC product Registration #5481-197 was approved on 

September 26, 2014. Amvac is no longer required to submit to the Agency documentation of the 

impurity profiles in each finished lot of the product; however, such documentation must be 

submitted to the Agency upon request. Amvac had been required to submit this information to 

resolve concerns about previously unreported toxic contaminants in the technical product, and 

had been doing so in accordance with the conditions of registration. The impurity profiles that 

were submitted have been consistent with prescribed limits for the impurities, and the Agency 

believes that information obtained on an as-needed basis will be sufficient in the future. 

Additionally, EPA is currently discussing with the registrants an issue regarding two PCNB 

products that do not conform to labeling on the technical product that prohibits the use of PCNB 

on residential lawns and related sites, and set limits for the use of PCNB on athletic fields. The 

registrants are expected to submit requests for label amendments consistent with the technical 

product labeling. When the amendments are approved and implemented, the use of any PCNB 

product will be prohibited on residential lawns and related sites, so an assessment of residential 

handler and post-application risks will not be needed. 

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW 

The most recent human health risk assessment in conjunction with the most recent aggregate risk 

assessment for PCNB was performed in 2005 for the RED. The most recent ecological and 

environmental fate risk assessment was completed 2005 for the same reason. Findings and 

conclusions from these risk assessments are summarized in Registration Review: Preliminary 

Problem Formulation for Environmental Fate, Ecological Risk, Endangered Species, and 

Human Health Drinking Water Exposure Assessments for Pentachloronitrobenzene (PCNB) and 

Pentachloronitrobenzene (PCNB) and Human Health Assessment Scoping Document in Support 

of Registration Review. 

Table 4 below summarizes the anticipated registration review risk assessments based on the 

EFED Problem Formulation and HED Scoping Document. 

10 
Table 4: Anticipated Risk Assessments for the PCNB Registration Review 

Comprehensive ecological 

(species to be assessed 

include terrestrial and aquatic 

organisms), including 

Food 

Drinking water 

Handlers (mixers, loaders, 

applicators) 

Post -application 

Post-application 

Bystanders 

Conduct? 

y 

y 

y 

y 

y 

N 

y 

The Agency will conduct a comprehensive ecological 

assessment, including an endangered species 

assessment. 

For a discussion of reported ecological incidents for 

29 of the Problem Formulation. 

Data anticipated to be required for the registration 

review of PCNB could result in changes to the point 

of departure (POD), necessitating a new dietary 

assessment. Likewise, if updated percent crop treated 

data, monitoring data, the most recent dietary 

exposure assessment model, and/or revised estimated 

drinking water concentrations result in significantly 

higher exposure and risk estimates, the Agency will 

revisit the assessment. 

An updated drinking water exposure assessment is 

anned for re · review. 

Updated occupational handler dermal and inhalation 

assessments may be conducted to reflect all currently 

registered uses and maximum application rates, 

current occupational and residential exposure 

assessment policies, and/or updated toxicological 

PODs, and data anticipated to be required for the 

re review ofPCNB. 

Occupational post-application dermal assessments 

may be conducted to reflect all currently registered 

uses and maximum application rates, current 

occupational residential exposure assessment (ORE) 

policies, and/or updated toxicological PODs, and data 

to be · for re ·strati on review. 

Pending amendment of non-conforming end-use 

product labels, residential handler and post-

. tions risk assessments will not be needed. 

The need for spray drift and volatilization risk 

assessment for PCNB will be examined during 

stration review. 

11 
Aggregate y A new aggregate risk assessment will be required due 

to updates to residential scenarios as well as potential 

updates to the dietary exposure assessment, 

toxicological endpoints, and/or the POD. 

Cumulative N The Agency has not made a common mechanism of 

toxicity finding for PCNB and other substances, and 

PCNB does not appear to produce a toxic metabolite 

produced by other substances. 

Tolerances y The Agency will revisit the tolerances during 

registration review. 

Incidents Will check for For a discussion of reported human incidents for 

updates PCNB, see page 11 of the Scoping Document and 

Pentachloronitrobenzene (PCNB): Tier 1 (Scoping 

Review of Human Incidents and Epidemiology. 

Guidance for Commenters: Additional ecological information requested for this registration 

review, and of particular interest to EPA, is described below. 

• Ecological and crop damage incidents not already reported to the Agency. 

Guidance for Commenters: Additional human health information requested for this 

registration review, and of particular interest to EPA, is described below. 

• Human health incidents not previously reported to the Agency. 

TIME LINE 

EPA has created the following estimated time line for the completion of the PCNB registration 

review in Table 5 below. 

12 
Table 5: Projected PCNB Registration Review Timeline 

Activities Estimated Date 

Opening the Docket 

Open Docket and 60-day Public Comment Period March-2016 

Close Public Comment May-2016 

Case Development 

Final Work Plan September 2016 

Issue DCI October-December 2016 

Data Submission October-December 20 18 

60-day Public Comment Period for Draft Risk April-June 2020 

Assessments 17 

Registration Review Decision 

60-day Public Comment Period for Proposed January-March 2021 

Registration Review Decision 

Registration Review Decision and Begin Post-Decision 2021 

Follow-up 

Total (years) 5 

NEXT STEPS 

After the 60-day public comment period closes, the Agency will review and respond to any 

comments received in a timely manner and then issue a Final Work Plan for the registration 

review of PCNB. 

17 The regulations governing Registration Review generally require the Agency to provide a public comment period 

of at least 30 calendar days for draft risk assessments; see 40 CFR Part 155.53(c). For conventional pesticides, the 

Agency plans to provide a 60 calendar day public comment period generally for draft risk assessments. 

13 
Appendix - Additional Areas Considered in the PCNB Registration Review 

PUBLIC COMMENTS AND FEEDBACK: 

Guidance for Commenters: The areas below highlight topics of special interest to the Agency 

where your comments, data submissions, or reference to sources of additional information could 

be of particular use. 

Trade Irritants: 

Through the registration review process, the Agency intends to solicit information on trade 

irritants and, to the extent feasible, take steps toward facilitating irritant resolution. The Agency 

will work to harmonize tolerances and international maximum residue limits (MRLs) and may 

modify tolerance levels to do so, when possible. Growers and other stakeholders are asked to 

comment on any trade irritant issues resulting from lack ofMRLs or disparities between U.S. 

tolerances and MRLs in key export markets, providing as much specificity as possible regarding 

the nature of the concern. 

Water Quality: 

PCNB is not identified as a cause of impairment for any water bodies listed as impaired under 

section 303(d) of the Clean Water Act. 18 In addition, no Total Maximum Daily Loads (TMDL) 

have been developed for PCNB. 19 More information on impaired water bodies and TMDLs can 

be found at the Agency's website. 20 The Agency invites submission of water quality data for 

this pesticide. To the extent possible, data should conform to the quality standards in Appendix 

A of the OPP Standard Operating Procedure: Inclusion of Impaired Water Body and Other 

Water Quality Data in OP P 's Registration Review Risk Assessment and Management Process21 

in order to ensure they can be used quantitatively or qualitatively in pesticide risk assessments. 

Environmental Justice: 

EPA seeks to achieve environmental justice, the fair treatment and meaningful involvement of all 

people, regardless of race, color, national origin, or income, in the development, implementation, 

and enforcement of environmental laws, regulations, and policies. To help address potential 

environmental justice issues, the Agency seeks information on any groups or segments of the 

population who, as a result of their location, cultural practices, or other factors, may have 

atypical, unusually high exposure to PCNB compared to the general population. Please 

comment if you are aware of any sub-populations that may have atypical, unusually high 

exposure compared to the general population. 

18 http://iaspub.epa.gov/tmdl waters I 0/attains nation cy.cause detail 303d?p cause group id=885 19http://iaspub.epa.gov/tmdl waters I 0/attains nation .tmdl pollutant detail?p pollutant group id=885&p pollutant 

group name=PESTICIDES 20 http://www.epa.gov/owow/tmdl/ 2 1 http://www2.epa.gov/pesticide-reevaluation/opp-guidance-submission-state-and-tribal-water-guality-monitoringdata 

14 
ENDANGERED SPECIES: 

A risk assessment that supports a complete endangered species determination has not been 

conducted for PCNB. The ecological risk assessment planned during registration review will 

allow the Agency to determine whether use of PCNB 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. 

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 reregistration decision for PCNB, 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 ), PCNB 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 withE, 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.22 A second list 

of chemicals identified for EDSP screening was published on June 14, 201323 and includes some 

pesticides scheduled for registration review and chemicals found in water. Neither of these lists 

should be construed as a list of known or likely endocrine disruptors. 

22 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2004-0109-0080 for the final initial list of 

chemicals. 

23 See http://www.regulations.gov/#! documentDetaii;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of 

chemicals. 

15 
PCNB, as "quintozene," was included in the first group of 67 chemicals issued an order to 

conduct Tier 1 EDSP testing, for which EPA has received all of the required Tier 1 assay data. 

The Agency has reviewed all of the assay data received for the List 1 chemicals and conclusions 

are available in the chemical-specific public dockets.24 The Agency has determined that there is 

no evidence of potential interaction of PCNB with the estrogen pathway in the mammals. 

However, PCNB may potentially interact with the estrogen pathway in wildlife based on the 

complementarity effects observed within the fish short-term reproduction assay and the results of 

the Tier 1 steroidogenesis assay. For the androgen pathway, there is no convincing evidence of 

potential interaction ofPCNB with mammals or wildlife. Additionally, there is no evidence of 

potential interaction of PCNB with the thyroid pathway in amphibians. There is evidence of 

potential interaction of PCNB with the thyroid pathway in mammals, although it is noted that the 

observed thyroid effects were consistently associated with alterations in the liver. In the EDSP 

Tier 1 assays and OSRI, there is evidence for potential interaction with the thyroid pathway in 

studies conducted with adult animals, but no such data exists for its effects in the young animals. 

For registration review, the Agency intends to require data to compare thyroid effects in adults 

and young. 

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

chemicals, future lists, the test guidelines, and the Tier 1 screening battery, please visit our 

website. 25 

HUMAN STUDIES: 

Past PCNB risk assessments rely in part on data from studies in which adult human subjects were 

intentionally exposed to a pesticide to determine their dermal and inhalation exposure. Many 

such studies, involving exposure to many different pesticides, comprise generic pesticide 

exposure databases such as the Pesticide Handlers Exposure Database (PHED), the Agricultural 

Reentry Task Force (ARTF) Database, and the Outdoor Residential Exposure Task Force 

(ORETF) Database. EPA has reviewed all the studies supporting these multi-pesticide generic 

exposure databases, and has found no clear and convincing evidence that the conduct of any of 

them was either fundamentally unethical or significantly deficient relative to the ethical 

standards prevailing at the time the research was conducted. All applicable requirements of 

EPA's Rule for the Protection ofHuman Subjects of Research (40 CFR Part 26) have been 

satisfied, and there is no regulatory barrier to continued reliance on these studies. 

24 http://www2.epa.gov/sites/production/files/20 15-06/documents/pcnb-056502 2015-06-29 txr0057138.pdf 25 http://www.epa.gov/endo/ 

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