UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MEMORANDUM 

Date: 03111 /2016 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

SUBJECT: Pentachloronitrobenzene (PCNB). Human Health Assessment Scoping 

Document in Support of Registration Review. 

PC Code: 056502 

Decision No.: 51041 1 

Petition No.: NIA 

DP Barcode: 0429798 

Registration No.: NIA 

Regulatory Action: Registration Review Scoping Document 

Risk Assessment Type: NIA Case No.: 0128 

TXR No.: NIA CAS No.: 82-68-8 

MRID No.: NIA 

FROM: 

40 CFR: § 180.291 

Shalu Shelat, Enviromnental Health Scientist 

Julie L. Van Alstine, Environmental Health Scientist 

Evisabel Craig, Ph.D., DABT, Toxicologist 

Risk Assessment Branch VT (RABVI) 

Health Effects Division (HED, 7509P) 

THROUGH: Donna S. Davis, Branch Chief 

RABVl/HED (7509P) 

TO: Veronica Dutch, Chemical Review Manager 

Jill Bloom, Team Lead 

Linda An-ington, Branch Chief 

Pesticide Re-Evaluation Division (PRO) (7508P) 

Attached is HED's human health risk assessment scoping document for pentachloronjtrobenzene 

(PCNB) to support Registration Review. 

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Table of Contents

Executive Summary........................................................................................................................ 3

1.0 Introduction ............................................................................................................................. 4

2.0 Hazard Characterization/Assessment....................................................................................... 5

3.0 Residue Chemistry................................................................................................................... 6

4.0 Dietary Exposure ..................................................................................................................... 7

5.0 Residential Exposure ............................................................................................................... 8

6.0 Non-occupational and Bystander Exposure.............................................................................. 8

7.0 Aggregate Risk Assessment..................................................................................................... 9

8.0 Occupational Exposure ............................................................................................................ 9

9.0 Public Health and Pesticide Epidemiology Data ................................................................... 10

10.0 Tolerance Assessment and International Harmonization .................................................... 11

11.0 Environmental Justice.......................................................................................................... 11

12.0 Cumulative........................................................................................................................... 11

13.0 Human Studies..................................................................................................................... 12

14.0 Risk Assessment Updates and Data Deficiencies................................................................ 12

15.0 References............................................................................................................................ 14

Attachment 1: Chemical Identity Tables. .................................................................................... 16

Attachment 2: PCNB Acute, Subchronic, and Chronic Toxicity Profile. ................................... 28

Attachment 3: Summary of Toxicological Doses and Endpoints for PCNB (from 2005 Risk 

Assessment). ................................................................................................................................. 32

Attachment 4: Summary of Residues of Concern for PCNB. ..................................................... 34

Attachment 5: PCNB International Residue Limit Status Sheet. ................................................ 35

Attachment 6: Summary of Registered Uses for PCNB.............................................................. 36

Attachment 7: PCNB DFR Waiver Criteria................................................................................. 46

Attachment 8. Residue Chemistry Data Needs for Registration Review of PCNB..................... 48
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Executive Summary

HED has prepared a scoping document to support Registration Review of the fungicide 

pentachloronitrobenzene (PCNB) (1,2,3,4,5-pentachloro-6-nitrobenzone). PCNB is an 

organochlorine contact fungicide for soil and limited foliar treatment around vegetables, field 

crops, turf (sod farms and golf courses), and ornamentals as well as residential turf. PCNB is 

formulated as liquid and granular formulations. 

The most recent human health risk assessment for PCNB was performed in 2005 entitled the 2nd

Revised HED Chapter of the Reregistration Eligibility Document (RED) (D. Locke, D312691, 

2/3/2005). In 2011, 2012, and 2013 HED performed three separate Occupational Exposure and 

Risk Assessments for only the impurities resulting from the PCNB manufacturing process (S. 

Shelat, D393194, 11/22/11; S. Shelat, D404118, 6/25/12; S. Shelat, D401422, 2/28/13). The 

impurity assessments resulted in risk mitigation, which has been implemented by the 

Registration Division on the current PCNB labels. 

HED has evaluated the status of the human health assessments for PCNB to determine whether 

sufficient data are available, and whether any updates are needed to support Registration Review. 

HED has considered all available data and human health risk assessments for PCNB with respect 

to its toxicity, exposure, and usage databases, and the most updated Agency science policy and 

risk assessment methodologies to determine the scope of work necessary to support Registration 

Review.

Based on the 2007 revised 40 CFR Toxicology Data Requirements, the toxicity database for 

PCNB is incomplete. The need for a subchronic inhalation study (guideline # 870.3465) for 

PCNB was recently confirmed by the HASPOC. Also, a special comparative thyroid assay 

(CTA) is required for PCNB because of the concern that points of departure (PODs) from adult 

animal studies may not be protective of potential thyroid toxicity in the young. As part of 

registration review, the endpoints, doses, and uncertainty/safety factors used in the most recent 

risk assessment will be re-evaluated according to current HED policy.

The residue chemistry database is not complete. The following studies are outstanding and 

should be submitted as part of Registration Review: an additional plant metabolism study on 

potatoes or cabbage (860.1300); new ruminant and poultry metabolism studies (860.1300); a 

livestock tolerance enforcement method (860.1340); storage stability data to support the 

cottonseed, peanut, potato, and tomato processing studies (860.1380); additional field trials on 

potatoes, garlic, broccoli, dry beans, lima beans, snap beans, soybeans, bell peppers, non-bell 

peppers, tomatoes, cottonseed, cotton gin byproducts, and peanuts (860.1500); livestock feeding 

studies (860.1480); and field accumulation studies on rotated crops (860.1900). There are no 

Codex or Canadian MRLs established for residues of PCNB and its metabolites; therefore, 

harmonization is not an issue at this time. The tolerance expressions in 40 CFR§180.291 have 

not been updated to reflect current HED policies and will need to be revised during Registration 

Review. 

The most recent chronic dietary (food and drinking water) risk estimates were below HED’s 

level of concern for the general U.S. population and all population subgroups examined. An 

acute assessment was not required. Additionally, for the purpose of risk characterization, it was 

recommended that the Reference Dose approach be used for quantification of human cancer 

risks. As part of Registration Review, an updated chronic dietary exposure and risk assessment 

may be required if updated percent crop treated (PCT) data, monitoring data, and/or estimated 
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drinking water concentrations (EDWCs) result in significantly higher exposure and risk 

estimates. This assessment should incorporate updated PCT data, monitoring data, updated 

EDWCs, the most recent dietary exposure assessment model, and any revised toxicological 

PODs. 

PCNB is currently registered for uses including golf courses and college and professional athletic 

fields. Although the technical registrant and most formulators have deleted residential turf uses 

for PCNB, two labels (EPA Reg. No. 10404-37 and 19713-312) currently exist which allow for 

use on residential turf, including lawns. For the residential turf uses, an adult residential handler 

dermal and inhalation assessment as well as adult dermal and children (1 to <2 years old) dermal 

and incidental oral assessments are anticipated during Registration Review. Based on the 

registration of PCNB on golf courses, this use also results in the potential for dermal postapplication exposure to adults and children (6 to < 11 years old and 11 to < 16 years old) who 

come into contact with treated golf course turf and will be considered during Registration 

Review. Updated residential handler dermal and inhalation assessments and post-application 

dermal and incidental oral assessments will be conducted to reflect all currently registered uses 

and maximum application rates, using current residential exposure policies and updated 

toxicological PODs. 

Based on the registered PCNB application methods, a spray drift assessment will be conducted 

during Registration Review. The need for a volatilization risk assessment for PCNB will be 

examined during Registration Review.

The occupational exposure database is not adequate to support the Registration Review process 

for PCNB. A chemical-specific DFR study will be needed to conduct the occupational postapplication foliar potato and magnolia tree assessment for PCNB. The risk estimates provided in 

the most recent 2005 PCNB occupational handler and post-application exposure assessments are 

not reflective of the mitigation established in the impurity assessment and current exposure 

policies. During Registration Review, updated occupational handler dermal and inhalation 

assessments and post-application dermal assessments may be conducted to reflect all currently 

registered uses and maximum application rates, using current occupational exposure policies and 

updated dermal and inhalation toxicological PODs, if needed. 

Additionally, as part of Registration Review, HED may also consider the impurities of PCNB in 

any dietary (food and water), residential, occupational, and/or aggregate exposure and risk 

assessments that are completed. 

1.0 Introduction

PCNB is an organochlorine fungicide that is effective in retarding germination and colony 

growth and suppressing sporulation. PCNB is formulated as a liquid formulation and granular 

formulation, and is currently registered for use on a variety of crops such as ornamentals; a 

variety of container grown crops; and agricultural crops including cole crops, beans, garlic, 

pepper, tomato, peanut, potato, and cotton, as well as sod farms, golf courses, college and 

professional athletic fields, and in residential turf settings. The most recent human health risk 

assessments were performed as part of the Reregistration Eligibility Decision document in 2005 

(D. Locke et al., D291281, 7/27/2004). Three subsequent occupational assessments were 

completed to address the exposure and risk estimates from the PCNB impurity only (S. Shelat, 

D393194, 11/22/11; S. Shelat, D404118, 6/25/12; S. Shelat, D401422, 2/28/13). The impurity 

assessments resulted in risk mitigation, which have been implemented by the Registration 
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Division on the current PCNB labels. 

2.0 Hazard Characterization/Assessment

The toxicology database for PCNB is incomplete. The current 40 CFR Part 158 Toxicology 

Data Requirements state that subchronic inhalation, immunotoxicity, metabolism, and 

neurotoxicity (acute and subchronic) studies are required for PCNB. The Hazard and Science 

Policy Council (HASPOC) recently confirmed the need for a subchronic inhalation study (TXR#

0057268, 2016). However, based on a weight-of-evidence (WOE) approach, the HASPOC 

determined that immunotoxicity, metabolism, and neurotoxicity (acute and subchronic) studies 

are not required at this time to support the registered uses of PCNB (TXR# 0057268, 2016). The 

HASPOC further concluded that, in agreement with the previous risk assessment, a comparative 

thyroid assay (CTA) is also required because of the concern that PODs from adult animal studies 

may not be protective of potential thyroid toxicity in the young (TXR# 0057268, 2016). The 

TOXLINE (National Library of Medicine) database literature search did not identify any new 

toxicological information not already considered. 

Subchronic and chronic studies in multiple species indicate that the thyroid and liver are target 

organs for PCNB. Effects include increases in thyroid weights, thyroid-stimulating hormone 

(TSH), aspartate transaminase (AST) and alanine aminotransferase (ALT) as well as hypertrophy 

of the thyroid and liver. No findings of significant toxicological concern were identified in the 

submitted developmental or reproductive toxicity data. No neurobehavioral alterations nor 

evidence of neuropathological effects were observed in the available data. There was no 

indication of increased susceptibility in these studies. 

PCNB is not mutagenic in bacteria or in cultured mammalian cells. There is suggestive in vitro 

evidence showing that PCNB is clastogenic in the absence of S9 activation and equivocal in the 

presence of S9 activation. However, in a more definitive erythrocyte mouse micronucleus assay, 

PCNB was not shown to be clastogenic. PCNB was also negative for the induction of sister 

chromatid exchanges (SCEs) in vitro. In 1992, the Cancer Peer Review Committee (CPRC) 

classified PCNB as a Group C- possible human carcinogen based on the presence of thyroid 

follicular cell adenomas and carcinomas in rats. CPRC recommended that for the purpose of risk 

characterization, the Reference Dose (RfD) approach should be used to quantify human risk.

Data from a series of limited single- and repeated-dose Rhesus monkey studies suggest that 

PCNB bioaccumulates in mammals. In this same series, it was noted that both the biliary-fecal 

and renal-urinary routes were utilized for the excretion of PCNB and its metabolites, with a 

slight preference for the fecal route. The limited data in rats, monkeys, and dogs suggest that the 

metabolites accumulated within tissues to a greater extent than parent PCNB. The available data 

in rats, monkeys, and dogs are considered sufficient for risk assessment purposes based on the 

profile of the chemical and the target organs.

Generally, PCNB has low acute toxicity via oral, dermal, or inhalation route (Toxicity Categories 

III or IV). It is a slight eye or skin irritant. Several studies indicate that PCNB is a sensitizer 

while others show negative results. The conflict in the outcome of these studies might be related 

to differences in impurities associated with variations in production batches and manufacturing 

sites, and/or differences in testing methodology.

There is no quantitative or qualitative evidence of increased susceptibility of rat or rabbit fetuses 

after in utero exposure (relative to structural abnormalities and developmental delays), or after 
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pre- or postnatal exposure to rats in multigeneration reproduction studies. Acceptable 

developmental toxicity studies in rats and rabbits, and reproductive toxicity studies are available 

and adequate for FQPA considerations. The previous risk assessment retained the FQPA safety 

factor of 10X because of the lack of a comparative thyroid and acceptable metabolism study. The 

HASPOC recently determined that a comparative thyroid study is required for PCNB. Therefore, 

upon the receipt of the required data, the need for the FQPA safety factor will be re-evaluated 

during Registration Review. PCNB is on List 1 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 appropriate List 

1 chemicals and the conclusions of those reviews are available in the chemical-specific public 

dockets (see Docket # OPP-2009-0634).

Conclusions for Hazard Identification/Toxicology

The toxicology database for PCNB is incomplete. A subchronic inhalation study and a CTA 

study are needed to support Registration Review. Upon receipt of these data, as part of 

Registration Review, the endpoints, doses, and uncertainty/safety factors used in the most recent 

risk assessment will be re-evaluated according to current HED policy.

3.0 Residue Chemistry

At the time of the RED, there were two technical registrants for PCNB, Uniroyal and Amvac. 

After examination of the toxicology and chemistry data submitted by Uniroyal and Amvac, the 

Hazard Identification Assessment Review Committee (HIARC, 1992) concluded that the PCNB 

technical materials from both of these registrants were so dissimilar they needed to be considered 

as separate and distinct chemicals based on differences in impurities and contaminants associated 

with the different manufacturing processes of the two registrants. As these registrants could not 

share information, separate data were required from both registrants to fulfill the residue 

chemistry data requirements. Currently, there is only one technical registrant for PCNB, Amvac. 

As such, only the Amvac residue chemistry database has been reviewed during the scoping 

process. 

A total of 84 polychlorinated phenyl metabolites of PCNB have been identified in livestock and 

plant metabolism and environmental degradate data. For identification and structures of each 

metabolite, see Table A.1.3 in Attachment 1. The limited data that are available suggest that 

generally, the metabolites of PCNB accumulate within plant and livestock tissues to a greater 

extent than the parent PCNB itself. The Metabolism Assessment Review Committee (MARC) 

concluded that the residues of concern for tolerance enforcement for plant and livestock 

commodities are PCNB and the metabolites pentachloraniline (PCA) and pentachlorothioisole 

(PCTA). Since all of the metabolites of PCNB are polychlorinated phenyl compounds and thus 

of toxicological concern, the MARC concluded that PCNB and all of its metabolites (including 

minor metabolites) are of concern in plant and livestock commodities for risk assessment. Due 

to the lack of monitoring and field trial data on every metabolite of PCNB in plants and 

livestock, for PCNB dietary risk assessments, the MARC recommended using plant and 

livestock metabolism studies to derive a ratio of all residues of concern to those residues in the 

tolerance expression (PCNB, PCA, PCTA), and using that ratio to estimate the concentration of 

residues of concern from field trial or monitoring data. A summary of the residues of concern 

for risk assessment and tolerance enforcement can be found in Attachment 4.

Several residue chemistry data deficiencies were previously identified for PCNB, and remain as 

deficiencies at this time. The available Amvac residue chemistry database is not complete and 

the following studies should be submitted as part of Registration Review: an additional plant 
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metabolism study on potatoes or cabbage; new ruminant and poultry metabolism studies; a 

livestock tolerance enforcement method; storage stability data to support the cottonseed, peanut, 

potato, and tomato processing studies; additional field trials on potatoes, garlic, broccoli, dry 

beans, lima beans, snap beans, soybeans, bell peppers, non-bell peppers, tomatoes, cottonseed, 

cotton gin byproducts, and peanuts; livestock feeding studies; and field accumulation studies on 

rotated crops. Additional details regarding the outstanding studies can be found in Attachment 8. 

A detailed discussion of the available Amvac PCNB residue chemistry database is available in 

the 2004 document (S. Kinard, D291280, 12/14/2004). The need for tolerances for residues in 

livestock will be examined during Registration Review. 

Conclusions: The Amvac residue chemistry database is not complete. The following studies are 

recommended to be required as part of Registration Review: an additional plant metabolism 

study; new ruminant and poultry metabolism studies; a livestock tolerance enforcement method; 

storage stability data to support the cottonseed, peanut, potato, and tomato processing studies; 

additional field trials on potatoes, garlic, broccoli, dry beans, lima beans, snap beans, soybeans, 

bell peppers, non-bell peppers, tomatoes, cottonseed, cotton gin byproducts, and peanuts; 

livestock feeding studies; and field accumulation studies on rotated crops. The need for 

livestock tolerances will be examined during Registration Review. Additionally, HED will 

review all impurities of PCNB as part of Registration Review. 

4.0 Dietary Exposure

The most recent chronic dietary assessment was conducted in 2005 to support HED’s RED (S. 

Kinard, D322231, 10/20/2005). The residues of concern for dietary risk assessment include 

PCNB and its 84 polychlorinated phenyl metabolites. An acute dietary assessment was not 

conducted for PCNB because an endpoint of concern attributable to a single dose was not 

identified. Additionally, HED’s Carcinogenicity Peer Review Committee (CARC) classified 

PCNB as a Group C - possible human carcinogen and recommended that for the purpose of risk 

characterization, the RfD approach should be used for quantification of the human cancer risk. 

The most recent chronic dietary (food and drinking water) assessment was refined and 

incorporated USDA Pesticide Data Program (PDP) monitoring data, anticipated residues, 

empirical processing data, and PCT data. The available monitoring data did not analyze all 

PCNB metabolites of concern; therefore, the assessment used total radioactive residue (TRR)

ratios based on the available metabolism studies to account for all metabolites of concern. 

EDWC values were provided by the Environmental Fate and Effects Division (EFED) and were 

directly incorporated into the assessments. The assessments were performed using Dietary 

Exposure Evaluation Model software with the Food Commodity Intake Database (DEEMFCID, Version 2.03), which uses food consumption data from the US Department of 

Agriculture’s (USDA’s) Continuing Surveys of Food Intakes by Individuals (CSFII) from 1994-

1996 and 1998. 

The chronic dietary (food and drinking water) risk estimates do not exceed HED’s level of 

concern (< 100% of the chronic population-adjusted dose (cPAD)). For registered commodities, 

the chronic dietary (food and drinking water) risk estimates were 32% of the cPAD for the 

general U.S. population and 77% of the cPAD for all infants less than 1 year old, the most 

highly-exposed population subgroup. 

Conclusions: The most recent chronic dietary (food and drinking water) risk estimates were 

below HED’s level of concern for the general U.S. population and all population subgroups 
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examined. An acute assessment was not required. Additionally, for the purpose of risk 

characterization, it was recommended that the RfD approach be used for quantification of human 

cancer risks. As part of Registration Review, an updated chronic dietary exposure and risk 

assessment may be required if updated PCT data, monitoring data, and/or EDWCs result in 

significantly higher exposure and risk estimates. This assessment should incorporate updated 

PCT data, monitoring data, updated EDWCs from EFED, the most recent dietary exposure 

assessment model, and any revised toxicological PODs. Additionally, as part of Registration 

Review, HED will consider the impurities of PCNB. 

5.0 Residential Exposure

In the 2005 risk assessment for PCNB, a residential handler assessment was conducted for use on 

residential lawns as well as post-application exposures to individuals entering treated lawns and 

golf courses. Some short-term risk estimates were of concern for residential handlers as well as 

post-application exposures on the day of treatment (i.e., Day 0) (i.e., dermal, incidental oral, and 

inhalation MOEs < 1000). In order to allow a safety finding under FQPA, Amvac requested the 

voluntary termination of lawn and related use sites from its PCNB registrations, as well as the

use of PCNB on golf course roughs. Most other registrants followed suit. Two labels (EPA Reg. 

No. 10404-37 and 19713-312) still allow for use on residential turf, including lawns. A 

chemical-specific turf transferable residue study (MRID 446871-01) is available for PCNB. 

For the residential turf uses, an adult residential handler dermal and inhalation assessment as 

well as adult dermal and children (1 to <2 years old) dermal and incidental oral assessments are 

anticipated during Registration Review. Based on the registration of PCNB on golf courses, this 

use also results in the potential for dermal post-application exposure to adults and children (6 to 

< 11 years old and 11 to < 16 years old) who come into contact with treated golf course turf, and 

these exposures will be considered during Registration Review.

Conclusions: The residential exposure database is adequate to support the Registration Review 

process for PCNB. The most recent residential handler and post-application exposure 

assessments are not reflective of current exposure patterns, policies and data. During Registration 

Review, updated residential dermal and inhalation handler assessments as well as dermal and 

incidental oral post-application assessments will be conducted to reflect all currently registered 

uses and maximum application rates, current ORE policies and/or updated toxicological PODs. 

6.0 Non-occupational and Bystander Exposure 

Residential bystander exposures resulting from off-site transport (e.g., spray drift or 

volatilization) may occur as a result of applications of PCNB. The potential for spray drift will 

be quantitatively evaluated for each pesticide during the Registration Review process that 

ensures that all uses for that pesticide will be considered concurrently. The approach is outlined 

in the revised (2012) Standard Operating Procedures for Residential Risk Assessment (SOPs) –

Residential Exposure Assessment Standard Operating Procedures Addenda 1: Consideration of 

Spray Drift. This document outlines the quantification of indirect non-occupational exposure to 

drift. 

In terms of volatilization, PCNB has been included as part of the Pesticide Action Network 

Pesticide Drift Monitoring in Minnesota report and these data will be assessed as part of 

Registration Review. In addition, the agency has developed a Volatilization Screening Tool and 

a subsequent Volatilization Screening Analysis 
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(http://www.regulations.gov/#!docketDetail;D=EPA-HQ-OPP-2014-0219). During Registration 

Review, the agency will utilize this analysis to determine if data (i.e., flux studies, route-specific 

inhalation toxicological studies) or further analyses are required for specific chemicals.

Conclusions: The need for spray drift and volatilization risk assessment for PCNB will be 

examined during Registration Review.

7.0 Aggregate Risk Assessment

The most recent aggregate risk assessment for PCNB was performed in conjunction with the 

2005 HED human health risk assessment (D. Locke, D312691, 2/3/2005). The Agency conducts 

aggregate exposure assessments by summing dietary (food and water) and residential exposures. 

An acute aggregate assessment was not conducted for PCNB because an endpoint of concern 

attributable to a single dose was not identified. The chronic aggregate risk assessment is equal to 

the chronic dietary estimates (food and water only). The short-term aggregate-risk assessment 

performed in 2005 included the short-term residential exposures and the chronic dietary 

exposures and resulted in risks of concern. 

Conclusions: A new aggregate risk assessment will be required due to updates to the residential 

scenarios as well as potential updates to the dietary exposure assessment. 

8.0 Occupational Exposure

PCNB is registered for use on a variety of crops, ornamentals, sod farms, and golf courses turf 

(tees, greens, and fairways). Attachment 6 provides a summary of the occupational use pattern. 

Based on the registered use patterns, there is a potential for dermal and inhalation exposure to 

PCNB in occupational scenarios from handling PCNB products during the application process 

(i.e., mixer/loaders, applicators, and mixer/loader/applicators). In addition, there is a potential 

for post-application worker exposure from entering into areas previously treated with PCNB. 

Occupational Handlers: In the 2005 risk assessment for PCNB, an occupational handler 

assessment was conducted for a variety of application methods and rates. There were non-cancer 

risk estimates of concern identified at that time. The assessment recommended either additional 

PPE or engineering controls be required for the affected scenarios. Based on the impurity 

assessments conducted in 2011, 2012, and 2013, the risk management division (RD) 

implemented additional mitigation for the PCNB labels. 

The 2005 risk assessment does not reflect the most up-to-date exposure data or inputs for 

occupational handlers, nor do they reflect the maximum application rates registered for this 

chemical. An updated occupational handler dermal and inhalation assessment may be conducted 

to reflect the maximum application rates and use parameters registered for PCNB using current 

ORE policies and updated toxicological PODs.

Occupational Post Application: In the 2005 risk assessment for PCNB, an occupational postapplication assessment was conducted only for the golf course and sod farm application 

scenarios. Since PCNB used on most other use sites is applied to soil directly and is soil 

incorporated before the plants mature, the assessment did not require a post-application 

assessment for the agricultural uses of PCNB. Short-term risk estimates were not of concern 

(i.e., MOEs ≥100) on the day of treatment (i.e., Day 0) for all post-application exposure activities 
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for the golf course and sod farm application scenarios. 

A turf transferable residue (TTR) study (MRID 446871-01) is available for PCNB. The study 

was used in the 2005 assessment as well as characterization in the 2011 golf course assessment 

and 2013 sod and athletic field assessment for the impurity. Although PCNB is applied to soil 

directly and is soil incorporated before the plants mature for most uses, current review of the 

labels have shown that there are two agricultural uses with the potential for foliar residue. The 

foliar chemigation use for potato and the registered use on magnolia trees both have the potential 

to result in dermal post-application exposure.

There is currently no chemical-specific dislodgeable foliar residue (DFR) study available for 

PCNB. Since the highest estimated occupational post-application exposure using default DFR 

values for PCNB is not minimal in comparison to the level of concern (i.e., the calculated MOE 

is not greater than 2 times higher than the level of concern, MOE = 17 compared to the LOC of 

100); EPA is requiring the 40CFR DFR data. Therefore, EPA is requiring the 40CFR DFR data 

requirement to facilitate any necessary exposure assessments refinements and to further EPA’s 

general understanding of the availability of dislodgeable foliar pesticide residues. See 

Attachment 7 for additional information regarding the DFR waiver criteria. 

The most recent occupational post-application exposure assessment is not reflective of current 

exposure policies and data, nor does it cover the highest application rate for some crops and the 

highest post-application activities. Therefore, a quantitative dermal post-application assessment 

may be required for PCNB during Registration Review.

Based on the Agency's current practices, a quantitative occupational post-application inhalation 

exposure assessment was not performed for PCNB at that time. If new policies or procedures are 

put into place, the Agency may revisit the need for a quantitative occupational post-application 

inhalation exposure assessment for PCNB.

Conclusions: The occupational exposure database is not adequate to support the Registration 

Review process for PCNB due to the lack of a chemical-specific DFR study. The most recent 

2005 occupational handler and post-application exposure assessments are not reflective of 

current exposure policies and data, and did identify risks of concern. During Registration 

Review, updated occupational handler dermal and inhalation assessments and post-application 

dermal assessments may be conducted to reflect all currently registered uses and maximum 

application rates, current ORE policies and/or updated toxicological PODs. 

9.0 Public Health and Pesticide Epidemiology Data

For this evaluation, both the OPP Incident Data System (IDS) and the Centers for Disease 

Control and Prevention/National Institute for Occupational Safety and Health (CDC/NIOSH) 

Sentinel Event Notification System for Occupational Risk-Pesticides (SENSOR) databases were 

consulted for pesticide incident data on the active ingredient PCNB. The purpose of the database 

search is to identify potential patterns in the frequency and severity of the health effects 

attributed to PCNB exposure. PCNB is not included in the Agricultural Health Study and 

therefore this study does not provide information for this report. 

For the Main IDS, from January 1, 2010 to September 22, 2015, there were no incidents reported 

for the single chemical PCNB only in the database. Aggregate IDS, from January 1, 2010 to 

September 22, 2015, there were two incidents reported involving PCNB. These incidents were 
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classified as minor severity. Overall, there are few incidents reported to IDS involving PCNB. A 

query of SENSOR-Pesticides from 1998-2011 identifies 18 cases involving PCNB; four of 

which involve a single ai. All four single ai cases are classified as low in severity and all four 

cases are work-related. Two cases, from two separate events, occurred at pesticide 

manufacturing facilities during the chemical manufacturing process. No further details were 

provided for these two cases. The remaining two cases occurred from the same event where one 

individual reported gastrointestinal symptoms and the other sought medical care. 

Based on the low frequency and severity of incident cases reported for PCNB in both IDS and 

SENSOR-Pesticides there does not appear to be a concern at this time that would warrant further 

investigation. The Agency will continue to monitor the incident information and if a concern is 

triggered, additional analysis will be included in the risk assessment.

10.0 Tolerance Assessment and International Harmonization

Tolerances for residues of PCNB and its metabolites PCA and PCTA are established for beans, 

Brassica head and stem subgroup 5A, cotton undelinted seed, garlic, peanut, potato, soybean 

(forage, hay, and seed), and fruiting vegetable crop group 8. Additionally, there are tolerances 

established based on regional registrations for collards, kale, and mustard greens. As part of 

Registration Review, the need for tolerances for residues in livestock commodities will be 

determined. There are no Codex or Canadian MRLs established for residues of PCNB and its 

metabolites; therefore, harmonization is not an issue at this time. The PCNB International 

Residue Limit Status Sheet is available in Attachment 5. The tolerance expressions in 40 

CFR§180.291 have not been updated to reflect current HED policies and will need to be revised 

during Registration Review.

11.0 Environmental Justice

Potential areas of environmental justice concerns, to the extent possible, were considered in the 

most recent PCNB human-health risk assessment, in accordance with U.S. Executive Order 

12898, “Federal Actions to Address Environmental Justice in Minority Populations and LowIncome Populationsa

.” The OPP typically considers the highest potential exposures from the 

legal use of a pesticide when conducting human health risk assessments, including, but not 

limited to, people who obtain drinking water from sources near agricultural areas, the variability 

of diets within the U.S., and people who may be exposed when harvesting crops. Should these 

highest exposures indicate potential risks of concern, OPP further refines the risk assessments to 

ensure that the risk estimates are based on the best available information.

12.0 Cumulative

Unlike other pesticides for which EPA has followed a cumulative risk approach based on a 

common mechanism of toxicity, EPA has not made a common mechanism of toxicity finding for 

PCNB and any other substances; and PCNB does not appear to produce a toxic metabolite 

produced by other substances. For the purposes of this tolerance action, therefore, EPA has 

assumed that PCNB does not have a common mechanism of toxicity with other substances. For 

information regarding EPA’s efforts to determine which chemicals have a common mechanism 

of toxicity and to evaluate the cumulative effects of such chemicals, see the policy statements 

released by EPA’s Office of Pesticide Programs concerning common mechanism determinations 

 

a http://www.epa.gov/compliance/environmentaljustice/resources/policy/exec_order_12898.pdf
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and procedures for cumulating effects from substances found to have a common mechanism on 

EPA’s website at http://www.epa.gov/pesticide-science-and-assessing-pesticiderisks/cumulative-assessment-risk-pesticides.

13.0 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 

Handler Exposure Task Force (AHETF) Database, and the Agricultural Reentry Task Force 

(ARTF) 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 of Human Subjects of Research (40 CFR Part 26) have been 

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

14.0 Risk Assessment Updates and Data Deficiencies

As part of Registration Review, HED will also review all impurities of PCNB. Amvac is 

encouraged to provide an analysis of the testing materials for any new studies submitted during 

Registration Review that addresses all impurities of concern. All new studies should be 

conducted with test material that has an impurity profile that is similar to the PCNB products that 

are currently in production. EPA notes the following risk assessment updates and data 

deficiencies will need to be completed and addressed during Registration Review:

o Toxicology: 

o A subchronic inhalation study is recommended to be required

o A CTA study is recommended to be required

o Residue Chemistry/Dietary Exposure: 

o Label changes are recommended for EPA Reg. Nos. 5481-8992, 5481-8988, and 100-

823. The recommended changes can be found in Attachment 8.

o The following studies are outstanding and are recommended to be required as part of 

Registration Review: an additional plant metabolism study on potatoes or cabbage

(860.1300); new ruminant and poultry metabolism studies (860.1300); a livestock 

tolerance enforcement method (860.1340); storage stability data to support the 

cottonseed, peanut, potato, and tomato processing studies (860.1380); livestock 

feeding studies (860.1480); and field accumulation studies on rotated crops 

(860.1900). Additional information about each data requirement can be found in 

Attachment 8.

o The following field trial data (860.1500) are recommended to be required as part of 

Registration Review. Additional information about each data requirement can be 

found in Attachment 8.

 Potatoes: An additional 35 field trials are required for potatoes using 10% 

G and 2 lb/gal EC formulations. Two sets of trials are required for each 

formulation, one set of pre-plant incorporated (PPI) field trials (9 trials per 

formulation) and one set of in-furrow application field trials (9 trials for 

the 10% G formulation and 8 trials for the 2 lb/gal EC formulation)
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 Garlic: Field trial data on garlic should be submitted by Amvac as part of 

Registration Review in accordance with 860.1500. 

 Broccoli: An additional 7 field trials are required for broccoli: 1) using a 

75% WP formulation at 30 lb ai/A as a broadcast PPI application (1 field 

trial) and as a banded application (1 field trial); 2) using a 75% WP 

formulation at 4.5 lb ai/100 gal. in soil drench application with a PHI > 72 

days (3 field trials); and 3) using a 10% G formulation at 30 lb ai/A in 

broadcast PPI application at transplant with a PHI > 72 days (1 field trial) 

and as a banded application with a PHI > 72 days (1 field trial). 

 Dry beans: An additional 8 field trials are required for dry beans with 2 

lb/gal EC (4 field trials) and 75% WP formulations (4 field trials) to match 

previously submitted data. 

 Lima beans: An additional 6 field trials are required for lima beans with 2 

lb/gal EC (3 field trials) and 75% WP formulations (3 field trials) to match 

previously submitted data. 

 Snap beans: An additional 12 field trials (6 per formulation; 75% WP and 

2 lb/gal EC) are required for snap beans. 

 HED notes that granular data are not available for dry, lima, and snap 

beans and should be submitted as part of Registration Review. 

Alternatively, EPA Reg. Nos. 100-823 and 5481-8988 could be revised to 

remove applications to beans. 

 Soybeans: Field trial data are required reflecting the use of PCNB on 

soybeans at the maximum application rate. Alternatively, the labels could 

be revised to prohibit the direct application of PCNB to soybeans, and 

field trials would not be required. 

 Bell peppers: An additional 6 bell pepper field trials (3 per application 

method) using each application type (in-furrow and soil drench) are 

needed. 

 Non-bell peppers: Two non-bell pepper field trials are needed for each 

application type (in-furrow and soil drench) for a total of 4 additional field 

trials.

 HED notes that granular data are not available for bell and non-bell 

peppers and should be submitted as part of Registration Review. 

Alternatively, EPA Reg. No. 5481-8988 can be revised to remove 

applications to peppers. 

 Tomatoes: An additional 14 tomato field trials are needed. 7 field trials 

should be completed using the soil drench application method and 7 field 

trials should be completed using the in-furrow application method. 

 HED notes that granular data are not available for tomatoes and should be 

submitted as part of Registration Review. Alternatively, EPA Reg. No. 

5481-8988 can be revised to remove applications to tomatoes. 

 Cottonseed: An additional 12 field trials (4 per formulation/application 

type) should be conducted with the following formulation and application 

types: 10% G in in-furrow application, 10% G in banded application, and 

EC formulation in in-furrow application.

 Cotton gin byproducts: At least 12 field trials (6 per formulation type) for 

cotton gin byproducts data are required. At least three field trials for each 

type of harvesting (stripper and picker) are needed, for a total of six field 

trials per application formulation/type. Current labels include flowable 

and granular formulations with in-furrow applications. 
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 Peanuts: A total of 30 additional field trials are needed for peanut. 9 field 

trials are needed with the 10% G formulation, 10 field trials are needed 

with the 75% WP formulation, and 11 field trials are needed with the 75% 

EC.

o The need for livestock tolerances will be examined during Registration Review. 

o An updated chronic dietary exposure and risk assessment may be completed that 

incorporates updated PCT data, monitoring data, updated EDWCs, the most recent 

version of DEEM-FCID, and any revised toxicological PODs.

o Updated tolerance expressions in 40 CFR§180.291 to reflect current HED policies.

o Occupational/Residential Exposure: 

o Updated residential and occupational handler and post-application assessments 

may be conducted to reflect all currently registered uses and maximum 

application rates, current ORE policies and/or updated inhalation toxicological 

PODs.

o The need for spray drift and volatilization risk assessments for PCNB will be 

examined during Registration Review.

o A Dislodgeable Foliar Residue study is recommended to be required for 

Registration Review. 

15.0 References

Memoranda Relevant to Registration Review.

Author Barcode Date Title

D. Locke et al. D312691 2/3/2005 PENTACHLORONITROBENZENE (PCNB): 2nd Revised 

HED Chapter of the Reregistration Eligibility Decision 

Document (RED). PC Code: 056502. Case#0128 List A. DP 

Barcode D312691.

S. Shelat et al. D393194 11/22/2011 Occupational Exposure and Risk Assessment for Dioxin 

from Tier I Uses of PCNB: Golf Courses (tees, greens, and 

fairways), Cole Crops, Cotton, Potato, and Ornamentals 

Bulb and Cut Flowers Soak

S. Shelat et al. D401418 6/25/12 Occupational Exposure and Risk Assessment for Dioxin 

from PCNB Foliar Use on Potatoes in the States of Idaho, 

Washington, Oregon, and Nevada

S. Shelat et al. D401422 2/28/13 Occupational Exposure and Risk Assessment for Dioxin 

from Various Tier II Uses of PCNB

M. Sahafeyan et 

al.

TXR

NO. 

0051921

5/27/2003

Pentachloronitrobenzene (PCNB). (List A, Case No.0128) 

The Outcome of the HED Metabolism Assessment Review 

Committee Held on April 16th, 2003 to discuss residues of 

concern in risk assessment and tolerance expression of 

Pentachloronitrobenzene (PCNB). Chemical 056502. 

M. Sahafeyan et 

al. D291353 4/8/2003

Pentachloronitrobenzene (PCNB). (List A, Case No.0128) 

Briefing Memorandum to Metabolism Assessment Review 

Committee to discuss PCNB residues of concern for 

inclusion in dietary risk assessment. Chemical 056502. DP 

Barcode: D291353.

S. Kinard D291280 12/14/2004

Pentachloronitrobenzene (PCNB). Revised Reregistration 

Eligibility Decision Document (RED): Product and Residue 

Chemistry Considerations. 

S. Kinard D322231 10/20/2005

Pentachloronitrobenzene (PCNB). Chronic Dietary 

Exposure Assessments for the Reregistration Eligibility 

Decision (RED).

S. Gallagher TXR No. 

0057268 3/10/2016 PCNB: Summary of Hazard and Science Policy Council (HASPOC) Meeting of October 15, 2015: Recommendation 
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Memoranda Relevant to Registration Review.

Author Barcode Date Title

on the Requirement for Acute Neurotoxicity, Subchronic 

Neurotoxicity, Immunotoxicity, Inhalation, Metabolism, and 

Comparative Thyroid studies.

E. Evans et al. D431876 3/2/2016 PCNB: Tier I (Scoping) Review of Human Incidents and 

Epidemiology

Attachments: 

Attachment 1: Chemical Identity Tables.

Attachment 2: PCNB Acute, Subchronic, and Chronic Toxicity Profile.

Attachment 3: Summary of Toxicological Doses and Endpoints for PCNB.

Attachment 4: Summary of Residues of Concern for PCNB.

Attachment 5: PCNB International Residue Limit Status Sheet.

Attachment 6: Summary of Registered Uses for PCNB.

Attachment 7: PCNB DFR Waiver Criteria.

Attachment 8: Residue Chemistry Data Needs for Registration Review of PCNB.
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Attachment 1: Chemical Identity Tables.

Table A.1.1. Test Compound Nomenclature.

Chemical structure

Common name Pentachloronitrobenzene, PCNB

Empirical formula C6Cl5NO2

IUPAC name pentachloronitrobenzene

CAS name 1,2,3,4,5-pentachloro-6-nitrobenzene

CAS number 82-68-8

PC Code 056502

End-use products (EP) Food/Feed Uses EPA Reg. Nos.: 5481-8992 (Flowable); 5481-8988 (Granular); 

100-823 (Granular)

Non-food Uses EPA Reg. Nos.: 5481-585 (Liquid); 19713-312 (Liquid); 9198-

183 (Granular); 9198-227 (Granular); 10404-37 (Granular); 34704-1087 

(Granular)

Table A.1.2. Physicochemical Properties of the Technical Grade Test Compound.

Parameter Value Reference

Molecular weight 295.3

Memo, D. Locke, 07-

JAN-2005; D311394

Specific gravity 1.718

Boiling point 328C

Melting point/melting range 142-145 C

Water solubility 440 ppb

Vapor pressure 1.13 x 10-4 mmHg

Table A.1.3 lists all the compounds that are associated with PCNB from its metabolism in plants, 

livestock, toxicity studies, and water Memo, M. Sahafeyan et al., April 8, 2003; D291353).

Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

#

Matrices (MRID in 

parentheses)

Chemical Name (other names in 

parenthesis) Structure

1

Potato (45307303)

peanut (45307302)

peanut roots (41562902)

whole potato, callus, and peel 

(41562903)

cabbage leaves (41562904)

chicken fat (41692801)

Rotational crops: lettuce, wheat 

forage, wheat straw (44577501)

pentachloronitrobenzene (PCNB)

NO2

Cl

Cl

Cl

Cl

Cl
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Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

2

Potato (45307303)

peanut (45307302)

whole potato and peel 

(41562903)

goat liver (41692805)

goat kidney (41692805)

goat omental fat (41692805)

goat renal fat (41692805)

goat milk (41692805)

chicken fat (41692801)

egg yolk (41692801)

Rotational crops: turnip top, 

turnip root, lettuce, wheat forage, 

wheat straw (44577501)

pentachloroaniline (PCA)

NH2

Cl

Cl

Cl

Cl

Cl

3

Potato (45307303)

whole potato and peel 

(41562903)

cabbage leaves (41562904)

chicken thigh (41692801)

egg yolk (41692801)

Rotational crops: turnip root, 

lettuce, wheat forage, wheat 

straw (44577501)

pentachlorothioanisole (PCTA)

or, 

(methyl pentachlorophenyl sulfide, 

MPCPS)

S

CH3

Cl

5

4

Potato (45307303)

peanut (45307302)

Rotational crops: lettuce 

(44577501)

S-(pentachlorophenyl) 

malonylcysteine (PCP-MalCys)

(C5MaCy)

SCH2CHCO2H

NHCCH2CO2H

O

Cl

5

5

Potato (45307303)

peanut (45307302)

Rotational crops: wheat forage, 

wheat straw (44577501)

aminotetrachlorobenzene sulfonic 

acid (AM TCB sulfonic acid)

(C4SANH)

(tetrachlorosulfanilic acid)

SO3H

Cl

4

NH2

6 Potato (45307303) pentachloroanisole (PCAN)

CH3

Cl

Cl

Cl

Cl

Cl

7

Potato (45307303)

egg yolks (41692801)

Rotational crops: lettuce, wheat 

forage, wheat straw (44577501)

pentachlorobenzene (PCB)

Cl

5
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Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

8

Potato (45307303)

peanut root (41562902)

whole potato, callus, and peel 

(41562903)

cabbage leaves (41562904)

goat liver (41692805)

goat urine (41692805)

chicken kidney (41692801)

N-hydroxypentachloroaniline 

(NOHPCA)

NHOH

Cl

Cl

Cl

Cl

Cl

9

Potato (45307303)

potato callus and peel 

(41562903)

S-(pentachlorophenyl)-γ-glutamyl 

cysteine

(PCP-GluCys)

SCH2CHCOOH

Cl

Cl

Cl

Cl

Cl

NHCOCH2CH2CHCOOH

NH2

10

Potato (45307303)

Rotational crops: wheat forage 

(44577501)

S-(pentachlorophenyl) glutathione 

(PCP-GSH)

SCH2CHCONHCH2COOH

Cl

Cl

Cl

Cl

Cl

NHCOCH2CH2CHCOOH

NH2

11

Potato (45307303)

peanut roots (41562902)

whole potato callus, and peel 

(41592903)

chicken excreta (41692801)

S-(pentachlorophenyl) 

malonylcysteine monomethyl ester 

(PCP-MalCys ester)

SCH2CHCOOH

Cl

Cl

Cl

Cl

Cl

NHCOCH2COCH3

O

12

Potato (45307303)

chicken fat (41692801)

goat kidney (41692805)

tetrachloroaniline methyl sulfoxide 

(TCA sulfoxide isomers)

NH2

Cl SOCH3 4

13 Potato (45307303) tetrachloro-methylthio-aniline 

sulfamate (TC-MET-A sulfamate)

NH-SO3H

Cl SCH3 4

14 Potato (45307303)

potato peel (41562903)

tetrachloronitrobenzene (TCNB 

isomers)

NO2

Cl

4

15 Potato (45307303) tetrachloronitrobenzene sulfonic acid 

(TCNB sulfonic acid isomers)

SO3H

Cl

4

NO2
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Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

16 Potato (45307303) tetrachloronitrothioanisole (TCNTA 

isomers)

NO2

Cl

4

SCH3

17 Potato (45307303) tetrachlorophenol methyl sulfoxide 

(TCP sulfoxide)

SOCH3

Cl

4

OH

18 Potato (45307303) tetrachlorothiophenol methyl 

sulfoxide (TCTP sulfoxide)

SOCH3

Cl

4

SH

19 Potato (45307303) tetrachlorothiophenol sulfonic acid 

(TCTP sulfonic acid)

SO3H

Cl

4

SH

20 Potato (45307303) aminotetrachloroaniline (AM TCA 

isomers)

NH2

Cl

4

NH2

21 Potato (45307303) aminotetrachloroaniline sulfamate 

(AM TCA sulfamate)

HN SO3H

Cl

4

NH2

22 Potato (45307303) hydroxytetrachloroaniline (OH TCA)

NH2

Cl

4

OH

23 Potato (45307303) N-hydroxyamino-tetrachloroaniline 

(NOHAM TCA)

NH2

Cl

4

NHOH

24 Potato (45307303) N-hydroxyamino-tetrachlorophenol 

(NOHAM TCP)

NHOH

Cl

4

OH

25 Potato (45307303) N-hydroxyaminotetrachlorothioanisole (NOHAM 

TCTA isomers)

NHOH

Cl

4

SCH3
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Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

26 Potato (45307303) S-(tetrachloro-methyl sulfoxyphenyl) glutathione (TC-MES-PGSH)

SCH2CHCONHCH2COOH

NHCOCH2CH2CHCOOH

NH2

Cl

4 SOCH3

27 Potato (45307303) S-(tetrachloro-methyl sulfoxyphenyl) malonylcysteine (TC-MESP-MalCys)

SCH2CHCOOH

NHCOCH2COOH

Cl

4 SOCH3

28 Potato (45307303)

peanut (45307302)

S-(tetrachloronitrophenyl) 

glutathione (TCNP-GSH)

SCH2CHCONHCH2COOH

NHCOCH2CH2CHCOOH

NH2

Cl

4 NO2

29

Potato (45307303)

Peanut (45307302) S-(tetrachloronitrophenyl) 

malonylcysteine (TCNP-MalCys)

SCH2CHCOOH

NHCOCH2COOH

Cl

4 NO2

30 Potato (45307303) S,Sʹ-(tetrachlorophenyl) diglutathione 

(TCP-diGSH)

Cl

4

SCH2CHCONHCH2COOH

NHCOCH2CH2CHCOOH

NH2

2

31 Potato (45307303) S,Sʹ-(tetrachlorophenyl) dithioacetate 

(TCP-dithioacetate)

Cl

4

SCH2COOH

2

32 Potato (45307303) S,Sʹ-(tetrachlorophenyl)-γ-glutamyl 

cysteine-cysteine (TCP-GluCys-Cys)

SCH2CHCOOH

Cl

4 SCH2

CHCOOH

NHCOCH2CH2CHCOOH

NH2

NH2

33 Potato (45307303) acetyl S,Sʹ-(tetrachlorophenyl) 

cysteine-cysteinyl α-hydroxyglutarate 

(AC TCP-Cys-CysHOG)

SCH2CHCOOH

Cl

4 SCH2

CHCOOH

NHCOCH2CH2CHCOOH

OH

NHCOCH3
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Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

34 Potato (45307303) trichloronitroaniline methyl sulfoxide 

(RCNA sulfoxide)

NH2

NO2

Cl SOCH3 3

35 Potato (45307303) N-hydroxy-trichloro-dimethylthioaniline (NOH RC-diMET-A)

NHOH

Cl

3

SCH3

2

36 Potato (45307303) N-hydroxyamino-trichloro-methoxyaniline (NOHAM RC-OME-A)

NHOH

OMe

Cl NH2 3

37 Potato (45307303) S,Sʹ-(trichloroanilino)-γglutamylcysteine-cysteine (RCAGluCys-Cys)

Cl

3

SCH2CHCOOH

NHCOCH2CH2CHCOOH

NH2

NH2

SCH2CHCOOH

NH2

38 peanut (45307302) N-malonyl-S-

(tetrachloroaminophenyl)-cysteine

SCH2CHCOOH

Cl

4

NH2

NHCOCH2COOH

39 Potato (45307303) S,Sʹ-(trichloronitrophenyl) malonyl cysteine-thioacetate (RCNP-MalCysthioacetate)

Cl

3

SCH2CHCOOH

NHCOCH2COOH

SCH2COOH

NO2

40 Potato (45307303) S,Sʹ-(trichlorothioanisole)-γ-glutamyl 

cysteine-cysteine (RCTA-GluCysCys)

Cl

3

SCH2CCOOH

NHCOCH2CH2CHCOOH

NH2

SCH2CHCOOH

SCH3

NH2

41 Potato (45307303) diacetyl S,Sʹ-(trichloro-anisole) 

glutathione-cysteine (diAC RCANGSH-Cys)

Cl

3

SCH2CHCONHCH2COOH

NHCOCH2CH2CHCOOH

NHCOCH3

SCH2CHCOOH

OMe

NHCOCH3
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Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

42 Potato (45307303) diacetyl S,Sʹ-(trichloro-thioanisole) 

diglutathione (diAC RCTAdiGluCys)

Cl

3

SCH3

SCH2CHCOOH

NHCOCH2CH2CHCOOH

NHCOCH3

2

43 Potato peel (41562903) Tetrachloronitrophenol (TCNP)

44 potato peel (41562903) Tetrachlorophenol (TCP)

45 peanut roots (41562902) Tetrachloroaniline (TCA)

46 goat urine (41692805) Pentachloroaniline sulfamate

47

Rotational crops: turnip top, 

turnip root, lettuce, wheat forage, 

wheat straw (44577501)

C5SA

pentachlorobenzenesulfonic acid

SO3H

Cl

5

48

goat liver (41692805)

goat kidney (41692805)

chicken excreta (41692801) 

chicken liver (41692801)

egg yolk (41692801)

Pentachlorothiophenol (PCTP)

49

cabbage leaves (41562904)

chicken liver (41692801)

Rotational crops: turnip top, 

turnip root, wheat forage, wheat 

straw (44577501)

Pentachlorothioanisole sulfoxide 

(PCTA sulfoxide) (PCTASO)

(C5MX)
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Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

50 goat kidney (41692805)

chicken fat (41692801) Tetrachlorothioanisole (TCTA)

51

cabbage leaves (41562904)

Rotational crops: wheat straw 

(44577501)

Tetrachlorophenyl methyl sulfoxide 

(TCPM sulfoxide)

(C4MX)

52

cabbage leaves (41562904)

chicken kidney (41692801)

chicken thigh (41692801)

Rotational Crops: turnip top, 

turnip root, lettuce (44577501)

Tetrachlorophenyl methyl sulfone 

(TCPM sulfone)

(TCTASOO)

(C4MS)

(TCP methyl sulfone)

53

cabbage (41562904)

Rotational crops: turnip top, 

turnip root, lettuce, wheat forage, 

wheat straw (44577501)

Trichlorophenyl methyl sulfone 

(RCPM sulfone)

(C3MS)

54 cabbage leaves (41562904) Trichlorophenol methyl sulfone 

(RCHM sulfone)

55

goat liver (41692805)

goat kidney (41692805)

goat urine (41692805)

Tetrachloro (methylthio) thiophenol

(TCTP S-Met)

56 goat liver (41692805) Pentachlorothiophenol dimer (PCTP 

dimer)

57

potato callus and peel 

(41562903)

goat urine (41692805)

Pentachlorothiophenyl conjugate 

(PCTP-X)
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Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

58

chicken excreta (41692801)

chicken kidney (41692801)

chicken liver (41692801)

chicken thigh (41692801)

S-(pentachlorophenyl) thioacetate

59 chicken excreta (41692801) S-(pentachlorophenyl) thiopyruvate

60

whole potato, callus, and peel 

(41562903)

chicken kidney (41692801)

S-(pentachlorophenyl) cysteine 

(PCP-Cys)

61 peanut roots (41562902) S-[(methylthio)tetrachlorophenyl]-2-

thioacetic acid (MTCP-TAA)

62 potato callus and peel 

(41562903)

Pentachlorothiophenyl glycoside 

(PCTP-Gly)

63 potato callus and peel 

(41562903)

Pentachlorophenol glycoside (PCPGly)

64 goat liver (41692805)

goat kidney (41692805)

N-(pentachloroaniline) glucuronide

(PCA-Gluc)
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Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

65

Rotational Crops: turnip top, 

turnip root (44577501)

Pentachlorophenol (PCP)

OH

Cl

5

66

Rotational crops: turnip top, 

turnip root, lettuce, wheat forage, 

wheat straw (44577501)

tetrachlorobenzenesulfonic acid

(C4SA)

SO3H

Cl

4

67

Rotational crops: turnip top, 

turnip root, wheat forage, wheat 

straw (44577501)

C3SA

trichlorobenzenesulfonic acid

SO3H

Cl

3

68

Rotational crops: turnip top, 

turnip root, wheat forage 

(44577501)

C2SA

dichlorobenzenesulfonic acid

SO3H

Cl

2

69 Rotational crops: wheat forage, 

wheat straw (44577501)

C4MXSA

tetrachlorosulfophenyl methyl 

sulfoxide

(tetrachlorothioanisole sulfoxide, 

sulfonic acid)

S

O CH3

SO3H

Cl

4

70 Rotational crops: wheat straw 

(44577501)

C3MXSA

trichlorosulfophenyl methyl sulfoxide 

(trichlorothioanisole sulfoxide, 

sulfonic acid)

S

O CH3

Cl

3

SO3H

71 Rotational crops: wheat straw 

(44577501)

C4MSSA

tetrachlorosulfophenyl methyl 

sulfone 

(tetrachlorothioanisole sulfone, 

sulfonic acid)

S

O CH3

O

Cl

4

SO3H
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Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

72

Rotational crops: turnip top, 

turnip root, wheat forage, wheat 

straw (44577501)

C3MSSA

trichlorosulfophenyl methyl sulfone 

(trichlorothioanisole sulfone, sulfonic 

acid)

S

O CH3

O

SO3H

Cl

3

73 Rotational crops: wheat straw 

(44577501)

C2MSSA

dichlorosulfophenyl methyl sulfone 

(dichlorothioanisole, sulfonic acid)

S

O CH3

O

CL2

SO3H

74 Rotational crops: wheat forage, 

wheat straw (44577501)

C3SANH

trichlorosulfanilic acid

SO3H

Cl

3

NH2

75 Rotational crops: wheat forage 

(44577501)

C3SAOH

hydroxy-trichlorobenzene sulfonic 

acid 

(trichloro-hydroxybenzene sulfonic 

acid)

SO3H

Cl

3

OH

76 Rotational crops: lettuce, wheat 

forage, wheat straw (44577501)

C4MeAcCy

N-{1-methyl-2[(tetrachlorophenyl)-

thio]ethyl}acetamide

(tetrachlorophenyl methyl cysteine)

SCH2CHCH3

Cl

4

HNCCH3

O

77 Rotational crops: lettuce, wheat 

forage (44577501)

C4MaCyFCy

S-(tetrachlorophenyl)-Nmalonylcysteine-S’-formylcysteine

SCH2CHCO2H

SCH2CHCO2H

Cl

4

NHCOH

NHCOCH2CO2H

78 Rotational crops: wheat forage 

(44577501)

C5SAHx b

pentachlorobenzenesulfonic acid 

hexose ester

SO3-hexose

Cl

5
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Table A.1.3. A compiled list of all metabolites of PCNB found in plant metabolism, animal metabolism, 

rotational crops, water, and rat (toxicity) studies.1

79 Rotational crops: wheat forage 

(44577501)

C4CyCy

S,S’-tetrachlorophenyl dicysteine

SCH2CHCO2H

SCH2CHCO2H

Cl

4

NH2

NH2

80 Rotational crops: lettuce 

(44577501)

C4CyFCy

S-(tetrachlorophenyl)-cysteine-S’-

formylcysteine

SCH2CHCO2H

SCH2CHCO2H

Cl

4

NHCOH

NH2

81 Rotational crops: turnip root, 

lettuce (44577501)

C3MSMaCy

N-malonyl-S-trichloro-

(methylsulfonophenyl)-L-cysteine

S-(trichlorophenyl methyl sulfone)-

malonyl cysteine

S

O

O

CH3

SCH2CHCO2H

Cl

3

NHCCH2CO2H

O

82

Rotational crops: turnip top, 

turnip root (44577501)

C2MSMaCy

N-malonyl-S-dichloro-

(methylsulfonophenyl)-L-cysteine

S-(dichlorophenyl methyl sulfone)-

malonyl cysteine

S

O

O

CH3

SCH2CHCO2H

Cl

2

NHCCH2CO2H

O

83 Goat liver (41692805) glucuronide of NOHPCA 

(NOHPCA-Gluc)

Cl

Cl

Cl

Cl

N

Cl

HO gluc

84 Water (minor degradate) pentachlorothioanisole sulfone 

(PCTASO2)

S

O

O

CH3

Cl

5

1 Memo, M. Sahafeyan et al., April 8, 2003; D291353.
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Attachment 2: PCNB Acute, Subchronic, and Chronic Toxicity Profile.

Table A. 2.1. Acute Toxicity for PCNB (Amvac)

Guideline No. Study Type MRIDs # Results

Toxicity 

Category

870.1100 Acute Oral 41443101 LD50 = >5050 mg/kg IV

870.1200 Acute Dermal 41443102 LD50 = >2020 mg/kg III

870.1300 Acute Inhalation 41443103 LC50 = > 6.49 mg/L III

870.2400 Primary Eye Irritation 41443104 Slight irritant III

870.2500 Primary Skin Irritation 41443105 Non irritant IV

870.2600 Dermal Sensitization 45236401

40734001

Sensitizer

Non-sensitizer

Table A.2.2 PCNB Subchronic, Chronic and Other Toxicity Profile

Guideline No./ Study 

Type

MRID No. (year)/ 

Classification 

/Doses

Results

870.3100

90-Day Oral Toxicity in 

Rats

42630801 (1993)

Supplementary

0, 20, 6000 ppm in diet

[equivalent to 0, 1, 333

mg/kg/d (males only)]

NOAEL = not determined

LOAEL = 1 mg/kg/day based on liver and thyroid 

hypertrophy.

870.3100

90-Day Oral Toxicity in 

Rats

42630801 (1992)

Acceptable/nonguideline

0, 5, 10, 100 or 1000 

mg/kg/d via gavage

NOAEL = 100 mg/kg/day

LOAEL = 1000 mg/kg/day based on increased relative 

liver weight and histopathological changes in the liver 

and thyroid.

870.3150

90-Day Oral Toxicity in 

mice

45609101 (1987)

Acceptable/guideline

1250ppm (males), 2500, 

5000 10000 and 20000 

ppm (males and females)

M: 225, 450, 900, 1800 

and 3600 mg/kg/day

F: 488, 975, 1950 and 

3900 mg/kg/day

NOAEL = 1250ppm (225 mg/kg/day) for males and 

2500 ppm (488 mg/kg/day) for females

LOAEL = 2500ppm (450 mg/kg/day) for males and 

5000ppm (975 mg/kg/day) for females based on 

increased absolute and relative liver weights

870.3200

21/28-Day Dermal 

Toxicity-rat

42416002 (1992)

Acceptable/nonguideline

0, 100, 300 and 1000 

mg/kg/day

NOAEL = 300 mg/kg/day

LOAEL = 1000 mg/kg/day based on the increased 

incidences of dilation of the thyroid follicles and 

hypertrophy of the thyroid follicular epithelium in 

males. No reported treatment-related effects in females.
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Table A.2.2 PCNB Subchronic, Chronic and Other Toxicity Profile

Guideline No./ Study 

Type

MRID No. (year)/ 

Classification 

/Doses

Results

870.3250

90-Day Dermal Toxicityrabbits

42413901 (1992)

Core minimum

0, 30, 300 and 1000 

mg/kg/day

NOAEL = 1000 mg/kg/day (HDT)

LOAEL = Not determined

870.3465

90-Day Inhalation Toxicity

Not available

870.3700a

Prenatal developmental in 

rats

40588601 (1988)

Guideline

0, 30, 600 and 1200 

mg/kg/day via gavage

Maternal NOAEL = 1200 mg/kg/day (HDT)

Maternal LOAEL = not determined

Developmental NOAEL = 1200 mg/kg/day (HDT)

Developmental LOAEL = not determined

870.3700b

Prenatal developmental in 

rabbits

40717102 (1988)

Core minimum

0, 6.25, 12.5, 125 and 

250 mg/kg/day via 

gavage

Maternal NOAEL = 12.5 mg/kg/day

Maternal LOAEL = 125 mg/kg/day based on decreased 

maternal body weight

Developmental NOAEL = 125 mg/kg/day

Developmental LOAEL = 250 mg/kg/day based on 

decreased fetal body weight

870.3700b

Prenatal developmental in 

rabbits

41361301 (1989)

Supplementary

0, 100, 300 and 900 

mg/kg/day via gavage

Maternal NOAEL = 300 mg/kg/day

Maternal LOAEL = 900 mg/kg/day based on clinical 

signs of toxicity, decreased food consumption, 

abortions and premature delivery

Developmental NOAEL = 900 mg/kg/day (HDT) 

Developmental LOAEL = not determined

870.3800

Reproduction and Fertility 

Effects- 2-generation rat

41918701 (1991)

Core minimum

0, 1.2, 169 and 344 

mg/kg/day in males and 

0, 1.5, 218 and 455 in 

females

Parental/Systemic NOAEL = 1.2 mg/kg/day

LOAEL = 169 mg/kg/day based on decreased body 

weight

Reproductive/Offspring NOAEL = 1.2 mg/kg/day

LOAEL = 169 mg/kg/day based on decreased mean 

pup weights

870.3800

Reproduction and Fertility 

Effects- 2-generation rat

43469301

43469302

43469303 (1994)

Acceptable

0, 10, 100 and 1000 

mg/kg/day

Parental/Systemic NOAEL = 10 mg/kg/day for males 

and 100 mg/kg/day for females

Parental/Systemic LOAEL = 100 mg/kg/day for males 

and 1000 mg/kg/day for females based on increases in 

hepatocellular hypertrophy and thyroid follicular cell 

hypertrophy/hyperplasia

Reproductive/Offspring NOAEL = 1000 mg/kg/day

Reproductive/Offspring LOAEL = not determined

870.4100a

Chronic Toxicity-2yr rat

See combined chronic toxicity/carcinogenicity study below

870.4100b

Chronic toxicity (1yr-dog)

41718600 and 41718601 

(1993)

Acceptable/guideline

0, 15, 150 and 1500 ppm 

(equivalent to 0, 0.375, 

3.75 and 37.5 

mg/kg/day)

NOAEL = 3.75 mg/kg/day

LOAEL = 37.5 mg/kg/day based on increased serum 

ALP and cholesterol, increased liver weight and 

hepatocellular hypertrophy.
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Table A.2.2 PCNB Subchronic, Chronic and Other Toxicity Profile

Guideline No./ Study 

Type

MRID No. (year)/ 

Classification 

/Doses

Results

870.4200a

Carcinogenicity-2yr rat

See combined chronic toxicity/carcinogenicity study below

870.4200b

Carcinogenicity (mouse)

45609101 (1987)

0, 400 and 1000 

mg/kg/day for males and 

0, 600 and 1400 

mg/kg/day for females

NOAEL = 1400 mg/kg/day

LOAEL = not determined

No evidence of carcinogenicity. Decreased survival 

due to infection was noted.

870.4300

Combined Chronic 

Toxicity/Carcinogenicity2yr rat

41987301 (1991)

Acceptable/Guideline

0, 1, 150, 300 mg/kg/day 

in the diet

NOAEL = 1 mg/kg/day

LOAEL = 150 mg/kg/day based on an increase in 

hepatocellular hypertrophy, hepatocellular hyperplasia, 

thyroid hypertrophy & hyperplasia, increase in thyroid 

follicular cell adenomas & carcinomas.

870.4300

Combined Chronic 

Toxicity/Carcinogenicity2yr rat

43015801 (1993)

Acceptable/Guideline

0, 3.6, 36, 357 and 714

mg/kg/day via gavage

NOAEL = 3.6 mg/kg/day for males and 36 mg/kg/day 

for females

LOAEL = 36 mg/kg/day for males and 357 mg/kg/day

for females based on hepatocellular hypertrophy & the 

thyroid follicular cell hypertrophy/hyperplasia. 

Negative for neoplasia.

870. 5265

Gene mutation-Ames assay

45609101 (1987)

Acceptable/guideline

0, 100, 333, 1000, 3333, 

6667 μg/plate (±S9)

Non-mutagenic when tested up to 6667 ug/plate, in 

presence and absence of activation, in S. typhimurium 

strains TA98, TA100, TA1535 and TA1537.

870.5300

Mammalian cell mutation 

assay

45609101 (1987)

Acceptable/guideline

0, 1.25, 2.50, 5.0, 7.5 

and 10.00 g/mL(±S9)

Non-mutagenic at the TK locus in L5178Y mouse 

lymphoma cells in presence and absence of S-9 

activation.

870.5375

Mammalian Cytogenetics 

Assay (CHO-K1 Cells)

45609101 (1987)

Acceptable/guideline

2.4, 7.5, 24 and 75

g/mL

Did not induce structural chromosome aberration in 

CHO-K1 cell cultures in the presence and absence of 

activation.

870.6200a

Acute Neurotoxicity 

Screening Battery

Not available.

870.6200b

Subchronic Neurotoxicity 

Screening Battery

Not available.

870.6300

Developmental 

Neurotoxicity

Not available.

870.7485

Metabolism and 

Pharmacokinetics-rats

248286 (1981)

Unacceptable

Single oral dose of 

5mg/kg

The majority of the dose was excreted in feces (81% 

feces and 5% urine after 3 days). Females excreted 

higher proportion of dose in urine than males. 

870.7485

Metabolism and 

Pharmacokinetics-monkeys

114233 (1979)

248286 

Unacceptable

Single oral dose of 2 

mg/kg to 6 males and 2 

females

Half-life was approximately 1.5 to 1.7 days. After 14 

days, 85% of dose was accounted for in urine and feces.
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Table A.2.2 PCNB Subchronic, Chronic and Other Toxicity Profile

Guideline No./ Study 

Type

MRID No. (year)/ 

Classification 

/Doses

Results

870.7600

Dermal penetration 

156046 (1986)

Unacceptable

Dermal pads were placed 

on workers (2-3 per 

scenario) using 

TERRACLOR for seed 

planting, vegetable 

transplanting or turf 

spraying.

Total exposure to workers wearing long sleeves and 

gloves was between 0.03 and 8.46 mg/kg/day

870.7800

Immunotoxicity

Not available.
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Attachment 3: Summary of Toxicological Doses and Endpoints for PCNB (from 2005 Risk 

Assessment).

Table A.3.1 Summary of Toxicological Doses and Endpoints for PCNB for Use in Dietary and Non-Occupational 

Human Health Risk Assessments

Exposure/ 

Scenario

Point of 

Departure

(mg/kg/day)

Uncertainty/

FQPA Safety 

Factors

RfD, PAD, Level of 

Concern for Risk 

Assessment

Study and Toxicological Effects

Acute Dietary No appropriate endpoint attributed to a single dose was identified. Therefore, an acute RfD was not 

established.

Chronic Dietary

NOAEL = 

1.0

UFA= 10x

UFH= 10x

FQPA SF= 10x

Chronic RfD = 0.01 

mg/kg/day

cPAD1= 0.001 

mg/kg/day

Combined chronic 

toxicity/carcinogenicity study in rats

MRID# 41987301

Systemic toxicity LOAEL = 150 

mg/kg/day, based on hepatocellular 

hypertrophy, hepatocellular 

hyperplasia (females) and thyroid 

hypertrophy and hyperplasia.

Incidental Oral, 

Short (1-30 days)- 

Term

NOAEL= 

1.0

UFA= 10x

UFH= 10x

FQPA SF= 10x

LOC for residential 

MOE = 1000

Nonguideline 90-day subchronic oral 

toxicity study in male rats

MRID# 42630801

Based on thyroid follicular epithelial 

hypertrophy observed at 333 

(LOAEL) after 14 & 30 days.

Incidental Oral, 

Intermediate (1-6 

months)-term

NOAEL= < 

1.0

UFA= 10x

UFH= 10x

FQPA SF= 10x

LOC for residential 

MOE = 1000

Nonguideline 90-day subchronic oral 

toxicity study in male rats

MRID# 42630801

LOAEL is 1.0 mg/kg/day based on 

liver & thyroid hypertrophy at 90 

days.

Dermal, Short (1-

30 days)- &

Intermediate (1-6 

months)-Term

NOAEL = 

300

UFA= 10x

UFH= 10x

FQPA SF= 10x

LOC for residential 

MOE = 1000

LOC for occupational 

MOE = 100

21-Day dermal toxicity study in male 

and female rats

MRID# 42416002

LOAEL is 1000 mg/kg/day based on 

hypertrophy of the thyroid follicular 

epithelium and dilation of the thyroid 

follicles in males only.

Dermal, LongTerm (6 months to 

life-time)

Absorption factor 

33% used for 

conversion from 

oral to dermal 

route

NOAEL = 

1.0

UFA= 10x

UFH= 10x

FQPA SF= 10x

LOC for residential 

MOE = 1000

LOC for occupational 

MOE = 100

Chronic toxicity/carcinogenicity 

study in rats

MRID# 41987301

Systemic toxicity LOAEL = 150 

mg/kg/day, based on hepatocellular 

hypertrophy, hepatocellular 

hyperplasia (females) and thyroid 

hypertrophy and hyperplasia.

Inhalation, Short 

(1-30 days)- Term

NOAEL= 

1.0

UFA= 10x

UFH= 10x

FQPA SF= 10x

LOC for residential 

MOE = 1000

LOC for occupational 

MOE = 100

Nonguideline 90-day subchronic oral 

toxicity study in male rats

MRID# 42630801
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Table A.3.1 Summary of Toxicological Doses and Endpoints for PCNB for Use in Dietary and Non-Occupational 

Human Health Risk Assessments

Exposure/ 

Scenario

Point of 

Departure

(mg/kg/day)

Uncertainty/

FQPA Safety 

Factors

RfD, PAD, Level of 

Concern for Risk 

Assessment

Study and Toxicological Effects

Based on thyroid follicular epithelial 

hypertrophy observed at 333 

(LOAEL) after 14 & 30 days.

Inhalation, 

Intermediate (1-6 

months)- Term

NOAEL= < 

1.0

UFA= 10x

UFH= 10x

FQPA SF= 10x

LOC for residential 

MOE = 1000

LOC for occupational 

MOE = 100

Nonguideline 90-day subchronic oral 

toxicity study in male rats

MRID# 42630801

LOAEL is 1.0 mg/kg/day based on 

liver & thyroid hypertrophy at 90 

days.

Inhalation, LongTerm (6 months to 

life-time)

NOAEL = 

1.0

UFA= 10x

UFH= 10x

FQPA SF= 10x

LOC for residential 

MOE = 1000

LOC for occupational 

MOE = 100

Chronic toxicity/carcinogenicity 

study in rats

MRID# 41987301

Systemic toxicity LOAEL = 150 

mg/kg/day, based on hepatocellular 

hypertrophy, hepatocellular 

hyperplasia (females) and thyroid 

hypertrophy and hyperplasia.

Cancer Group C - Possible human carcinogen. Combined incidence of thyroid follicular cell adenomas & 

carcinomas significantly increased in male but not female rats, with a significant trend in both sexes.

Q1* not calculated (not required)
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Attachment 4: Summary of Residues of Concern for PCNB. 

Table A.4. Summary of Residues of Concern for PCNB1

Chemical: PCNB (pentachloronitrobenzene)

Date: 16-April-2003

Residues of Concern2

Matrix For Risk Assessment For Tolerance Expression

Plants - Primary crops Parent plus all identified 

metabolites

Parent, PCA, PCTA

Plants - Rotational crops Parent plus all identified 

metabolites

Parent, PCA, PCTA

Livestock - Ruminant Parent plus all identified 

metabolites 

Parent, PCA, PCTA

Livestock- Poultry Parent plus all identified 

metabolites

Parent, PCA, PCTA

Water Parent, PCA, and PCP N/A

1 Table from Memo, M. Sahafeyan et al., May 27, 2003; TXR NO. 0051921.

2 PCA = pentachloraniline; PCTA = pentachlorothioisole or methyl pentachlorophenyl sulfide; PCP = 

pentachlorophenol.
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Attachment 5: PCNB International Residue Limit Status Sheet.

Pentachloronitrobenzene (PC Code 056502)

Summary of US and International Tolerances and Maximum Residue Limits. 

Residue Definition:

US Canada Mexico1 Codex

40 CFR §180. 291

(a) Primary Crops: the combined residues of the fungicide 

pentachloronitrobenzene (PCNB) and its metabolites 

pentachloroaniline (PCA), and pentachlorothioanisole 

(PCTA)

None None

Commodity Tolerance (ppm) /Maximum Residue Limit (mg/kg)

US Canada Mexico1 Codex

Bean 0.1 

Brassica, head and stem, subgroup 

5A

0.1

Cotton, undelinted seed 0.1

Garlic, bulb 0.1

Peanut 1

Potato 0.1

Soybean, forage 0.02

Soybean, hay 0.02

Soybean, seed 0.02

Vegetable, fruiting, group 8 0.1

Completed: M. Negussie; 01/19/16

1 Mexico adopts US tolerances and/or Codex MRLs for its export purposes.

(c) Tolerances with regional registrations. Tolerances with regional registrations, as defined in 

§180.1(l), are established for the combined residues of the fungicide pentachloronitrobenzene 

(PCNB) and its metabolites pentachloroaniline (PCA), and pentachlorothioanisole (PCTA), in or 

on the following food commodities:

Commodity Parts per million

Collards 0.2

Kale 0.2

Mustard, greens 0.2
Page 36 of 55

Attachment 6: Summary of Registered Uses for PCNB

TableA.6.1. Proposed Use Patterns and Formulations Assessed

Formulation Use Sites Application 

Equipment

PCNB Max 

Application Rates

(lbs ai/A)

Max rate per 

crop season 

(lb ai/A)

REI Application directions2

Flowable

5481-8992

Golf Courses groundboom 32.67 66 N/A

At first sign of disease (foliar application)

Do not mix/load more than 150 gallons of 

product per day

Athletic fields groundboom 32.67 66 N/A

Applications are limited to Fall and Winter 

months for pink and grey snow mold, no 

more than 3 applications per season (OctMar) with 14 day application intervals; 

treated area must be irrigated with 1⁄4 inch of 

water and left idle for at least 2 days after 

application. For all Non-Residential Turf use 

applications, Mixers and Loaders cannot 

handle more than 150 gallons product per 

day (equivalent to 600 lbs. A.I. /day).

Sod Farms groundboom 32.67 66 N/A

For Sod farm applications, applicators cannot 

handle more than 425 gallons of product per 

day (equivalent to 1,700 lbs. A.I. /day).

Woody plants

Groundboom, 

chemigation, manuallypressurized handwand, 

backpack sprayer, 

mechanicallypressurized handgun 

sprayer

40.8

(0.00375 lbs 

ai/gallon) N/S 12

Soil drench, bed, bench, container, and fieldgrown plants.

Use of any hand-held application equipment 

is prohibited except for greenhouse use.

Groundboom applicators cannot handle 

more than 425 gallons of product per day 

(equivalent to 1,700 lbs. A.I. /day).

Groundboom and chemigation 

applications: mixers/loaders cannot 

handle more than 190 gallons of product 

per day (equivalent to 760 lbs. A.I. /day).

Groundboom 114 Broadcast incorporated
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TableA.6.1. Proposed Use Patterns and Formulations Assessed

Formulation Use Sites Application 

Equipment

PCNB Max 

Application Rates

(lbs ai/A)

Max rate per 

crop season 

(lb ai/A)

REI Application directions2

Bulb soak 

(gladiolus, 

hyacinth, iris, 

narcissus, 

tulip)

Mixer/Loader Liquids 0.468

Lbs ai/gallon N/S 12

Soak bulbs for 5 minutes

Use of any hand-held application equipment 

is prohibited except for greenhouse use.

Bulb soak 

(lilies) Mixer/Loader Liquids 0.045Lbs ai/gallon N/S 12

Soak bulbs for 5 to 15 minutes

Use of any hand-held application equipment 

is prohibited except for greenhouse use.

Southern 

magnolia 

trees

Airblast, chemigation, 

manually-pressurized 

handwand, backpack 

sprayer, mechanicallypressurized handgun 

sprayer

32.67 N/S

12

Foliar spray application; Apply 4 sprays are 

2 week intervals

Airblast application may be used on 

Southern Magnolia Trees, applicators 

cannot handle more than 4.5 gallons of 

product per day (18 lbs. A.I. /day).

Groundboom applicators cannot handle 

more than 425 gallons of product per day 

(equivalent to 1,700 lbs. A.I. /day). 

Groundboom, airblast, and chemigation 

applications: mixers/loaders cannot 

handle more than 190 gallons of product 

per day (equivalent to 760 lbs. A.I. /day).

Soil drench mixer/loader/applicators 

cannot handle more than 0.42 gallons 

product per day (equivalent to 1.68 lbs.

A.I. /day).

Southern Pine 

seed or 

seedlings

Groundboom, 

chemigation

43.56 N/S

Broadcast prior to planting

Groundboom applicators cannot handle 

more than 425 gallons of product per day 

(equivalent to 1,700 lbs. A.I. /day). 

Groundboom, airblast, and chemigation 

applications: mixers/loaders cannot 

handle more than 190 gallons of product 

per day (equivalent to 760 lbs. A.I. /day).
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TableA.6.1. Proposed Use Patterns and Formulations Assessed

Formulation Use Sites Application 

Equipment

PCNB Max 

Application Rates

(lbs ai/A)

Max rate per 

crop season 

(lb ai/A)

REI Application directions2

Vegetable 

bedding 

plants 

Container 

grown (cole 

crops, 

peppers, 

tomatoes)

Groundboom, 

chemigation, manuallypressurized handwand, 

backpack sprayer, 

mechanicallypressurized handgun 

sprayer

20.4 20.4

12

Soil drench applications in the nursery or 

greenhouse to seedlings grown in containers 

or beds prior to transplanting into the field; 

do not exceed 22.5 lbs ai/A in any one season

Use of any hand-held application equipment 

is prohibited except for greenhouse use. For 

Groundboom applicators cannot handle 

more than 425 gallons of product per day 

(equivalent to 1,700 lbs. A.I. /day). 

Groundboom, airblast, and chemigation 

applications: mixers/loaders cannot 

handle more than 190 gallons of product 

per day (equivalent to 760 lbs. A.I. /day).

For Vegetable Bedding Plants, 

applicators cannot handle more than 1 

pint product per 1000 square feet 

(equivalent to 20.4 lbs. A.I. /Acre) per 

season.

Soil drench mixer/loader/applicators 

cannot handle more than 0.42 gallons 

product per day (equivalent to 1.68 lbs. 

A.I. /day).

Cole Crops

(Broccoli*, 

Brussels

Sprouts*, 

Cabbage*,

Chinese 

Broccoli*,

groundboom 22.5 22.5

Pre-plant, soil-directed

For Cole Crop applications, Mixers and 

Loaders cannot handle more than 150 gallons 

product per day (equivalent to 600 lbs. A.I. 

/day). Applicators cannot apply more than 

337 gallons of product per day (1,350 lbs. 

A.I. /day)
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TableA.6.1. Proposed Use Patterns and Formulations Assessed

Formulation Use Sites Application 

Equipment

PCNB Max 

Application Rates

(lbs ai/A)

Max rate per 

crop season 

(lb ai/A)

REI Application directions2

Cauliflower*, 

Chinese

Cabbage* 

(tightheaded

varieties

only), 

Collards*,

Kale*, 

Mustard

Greens*)

Groundboom, 

manually-pressurized 

handwand, backpack 

sprayer, mechanicallypressurized handgun 

sprayer

1.5

0.015 lbs ai./gallon

Transplant Solution: Use a maximum of 0.75 

pints of solution per plant; do not exceed 

22.5 lbs ai/A in any one season

Use of any hand-held application equipment 

is prohibited except for greenhouse use.

Beans (Dry, 

snap, or 

succulent)

Groundboom 1.5 10 Band row treatment; do not exceed 10 lbs 

ai/A in any one season

Beans (Dry or 

snap) Groundboom 2 10 Band row treatment; ; do not exceed 10 lbs ai/A in any one season

Garlic Groundboom 20 20

In furrow; ; do not exceed 20 lbs ai/A in any 

one season

For Garlic and Peanut applications, 

mixers/loaders cannot handle more than 190 

gallons of product per day (equivalent to 760 

lbs. A.I. /day).

Pepper/ 

Tomato

Groundboom; 

manually-pressurized 

handwand, backpack 

sprayer, mechanicallypressurized handgun 

sprayer

0.0375 lbs ai/gallon

7.5 12

Transplanting; do not exceed 7.5 lbs ai/A in 

any one season

For Peppers and Tomatoes, 

mixers/loaders/applicators cannot handle 

more than 0.42 gallons product per day 

(equivalent to 1.68 lbs. A.I. /day).

Groundboom 7.5 In-furrow; do not exceed 7.5 lbs ai/A in any 

one season
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TableA.6.1. Proposed Use Patterns and Formulations Assessed

Formulation Use Sites Application 

Equipment

PCNB Max 

Application Rates

(lbs ai/A)

Max rate per 

crop season 

(lb ai/A)

REI Application directions2

Peanut

Groundboom 2

10

Pre-plant soil mix; application can be made 

simultaneously with planting; do not exceed 

10 lbs ai/A in any one season

For Garlic and Peanut applications, 

mixers/loaders cannot handle more than 190 

gallons of product per day (equivalent to 760 

lbs. A.I. /day).

Groundboom 10 At pegging bands; do not exceed 10 lbs ai/A 

in any one season

Groundboom 3.25 At cultivation; do not exceed 20 lbs ai/A in 

any one season

Potato

Groundboom 5

5

Band application; do not exceed 5 lbs ai/A in 

any one season

Chemigation 2.5

Foliar use through chemigation; do not 

exceed 5 lbs ai/A per year.

For Chemigation applications to potatoes, 

Mixers and Loaders cannot handle more than 

150 gallons of product per day (equivalent to 

600 lbs. A.I. /day).

Cotton Groundboom 2 2

In-furrow; do not exceed 2 lbs ai/A in any 

one season

Liquid

(EPA Reg 

No. 5481-

585)

Golf Courses Groundboom 16.43 43.56 N/A

Mixers and Loaders cannot handle more than 

150 gallons of product per day (equivalent to 

601 lbs. AI of PCNB/day). Use of any handheld application equipment is prohibited.

Liquid

(EPA Reg 

No. 19713-

312)

Lawns and 

Ornamental 

Turf

Ground and handheld 

equipment 21.7

N/S N/A

Apply with sprinkler can, hand sprayer, or 

any other convenient method of obtaining 

even coverage. Then, lightly water the 

treated area to insure movement of the 

chemical through the grass to the soil level. 

Retreat the area 3 - 4 weeks later if it has 

been subjected to unusually heavy rainfall, or 

is flooded, or if the disease is severe or 

reappears.

Ornamentals 

(Azaleas and 

Camellias)

Soil Drench 217.7
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TableA.6.1. Proposed Use Patterns and Formulations Assessed

Formulation Use Sites Application 

Equipment

PCNB Max 

Application Rates

(lbs ai/A)

Max rate per 

crop season 

(lb ai/A)

REI Application directions2

GRANULAR

Granules 

(10% ai)

5481-8988

Sod Farms spreader 43.56 87.12

For Sod farm applications, Mixers/loaders 

cannot handle more than 23,000 Ibs. of 

product per day (equivalent to 2,300 Ibs. A.I. 

/day), Applicators cannot handle more than 

26,000 Ibs. of product per day (equivalent to 

2,600 Ibs. A.I. /day).

Golf Courses spreader 43.56 87.12

Apply on application in the spring or at sign 

of first disease; immediately irrigate with 1⁄4 

inch water

College and 

professional 

athletic fields

spreader 32.67 66

Make application prior to first snowfall or in 

the absence of snow cover; apply at 4 to 6 

week intervals; treated areas much be 

irrigated with 1⁄4 inch of water on day of 

application

Woody 

Ornamentals

Spreader

handheld equipment 

(only for growing 

media mix)

65.34

12 

hours

For Woody Ornamentals: Mixers/loaders 

cannot handle more than 23,000 Ibs. of 

product per day (equivalent to 2,300 Ibs. A.I. 

/day), Granular spreader applicators cannot 

handle more than 26,000 Ibs. of product per 

day (equivalent to 2,600 Ibs. A.I. /day), 

Backpack applicators cannot handle more 

than 1,300 Ibs. of product per day 

(equivalent to 130 Ibs. A.I. /day)

GROWING MEDIA MIX: Mix 1 to 1.5 Ibs. 

of product per cubic yard of media. To 

prevent agglomeration, ensure that 

ingredients are dry and free of large bumps. 

Blend thoroughly to ensure uniform 

distribution throughout the mixture. Use the 

lower rate for mixtures used at the time of 

seeding or transplanting of young seedlings 

or plugs. Use the higher rate for older plants 

or nursery stock. Do not mix more than 1 0 

cubic yards of media mix /day.

87.12

0.15 (lbs ai/cubic 

yard media) N/S
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TableA.6.1. Proposed Use Patterns and Formulations Assessed

Formulation Use Sites Application 

Equipment

PCNB Max 

Application Rates

(lbs ai/A)

Max rate per 

crop season 

(lb ai/A)

REI Application directions2

Vegetable 

bedding 

plants 

Container 

grown (beans. 

cole crops, 

peppers, 

tomatoes)

Spreader

0.15

(lbs ai/cubic yard 

media)

N/S

Mixers and Loaders cannot handle more than 

23,000 Ibs. of product/day (equivalent to 

2,300 Ibs. A.I. /day). Applicators using 

granular spreader equipment for broadcast 

and band applications cannot handle more 

than 26,000 Ibs. of product/day (equivalent 

to 2,600 Ibs. A.I. /day). Backpack applicators 

cannot handle more than 1,300 Ibs. of 

product per day (equivalent to 130 Ibs. A.I. 

/day)

GROWING MEDIA MIX: Mix 1 to 1.5 Ibs. 

of product per cubic yard of media. To 

prevent agglomeration, ensure that 

ingredients are dry and free of large bumps. 

Blend thoroughly to ensure uniform 

distribution throughout the mixture. Use the 

lower rate for mixtures used at the time of 

seeding or transplanting of young seedlings 

or plugs. Use the higher rate for older plants 

or nursery stock. Do not mix more than 1 0 

cubic yards of media mix /day.

Cole crops 

(cabbage, 

cauliflower, 

Brussels 

sprouts, 

broccoli, 

collards, kale, 

mustard)

Tractor drawn spreader

22.5

Pre-plant transplant row treatment; apply in a 

12-15 inch band

BROADCAST TREATMENT: Broadcast 

application to soil surface prior to planting; 

including Band Row Treatment for 

cauliflower

BAND TREATMENT: Apply in an 8-inch 

wide band centered on the row immediately 

before planting. Mix granules into soil before 

planting to a depth of 2 inches.

22.5

Peppers Tractor drawn spreader 4.4

In furrow application at time of planting; 

apply to the soil around the seed and to the 

covering soil as it fills the furrow
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TableA.6.1. Proposed Use Patterns and Formulations Assessed

Formulation Use Sites Application 

Equipment

PCNB Max 

Application Rates

(lbs ai/A)

Max rate per 

crop season 

(lb ai/A)

REI Application directions2

Potato Tractor drawn spreader 2.54

IN-FURROW BAND TREATMENT: Apply 

in a 8.5-inch band with 34" row spacing. 

Direct the product into the furrow over the 

seed and cover as part of the hilling operation 

during planting. It is best to apply when the 

soil is slightly moist. Do not harvest within 

45 days of application.

Beans (Bush 

beans) Tractor drawn spreader 4.36

APPLY AS AN IN-FURROW SOIL BAND 

TREATMENT. Apply in a 12 to 15-inch 

band. Apply over the seed at planting time in 

the furrow and immediately cover with soil 

utilizing appropriate application equipment. 

Do not feed treated vines to livestock.

Beans (Pole 

beans) Tractor drawn spreader 8.71

Peanuts Tractor drawn spreader

9.98

Do not 

exceed 10 Ibs. 

A.I. /A per 

season 

regardless of 

the 

application 

methods used.

IN-FURROW: Apply in a 12 to 15-inch 

band. Apply in furrow at planting using 

suitable equipment.

4.36

AS A SOIL MIX DURING CULTIVATION 

- Turfcide 10% Granular may be applied in 

two applications with the first application 

made at pegging (approximately 60 days 

after planting) and the second made 

approximately 30 days later. Apply at the 

rate of 14 Ibs. / 12,400 linear feet of row in a 

12-inch band. Do not apply more than 28 Ibs. 

of product per 12,400 feet of row in one year. 

Apply by attaching two delivery tubes per 

row (or bed if two rows per bed) and adjust 

so as to treat a total band of 12- inches wide 

centered on the row. Lightly incorporate to 

move the product into the soil. Do not pile 

untreated soil on crown of plant.
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TableA.6.1. Proposed Use Patterns and Formulations Assessed

Formulation Use Sites Application 

Equipment

PCNB Max 

Application Rates

(lbs ai/A)

Max rate per 

crop season 

(lb ai/A)

REI Application directions2

Cotton Tractor drawn spreader 2 N/S

IN-FURROW SOIL TREATMENT: Apply 

in a 12 to 15-inch band with 40" row 

spacing. Apply over the seed and 

immediately cover with soil at planting time. 

Do not allow livestock to graze or feed on 

cotton foliage in treated fields.

Granular

(EPA Reg 

No. 100-823)

Beans

Ground application

Aerial not prohibited

handheld not prohibted

3.3 N/S

48 

hours

Cotton 1 N/S

Peanuts 5 7.5

Do not apply more than 75 Ibs. of :Ridomil 

Gold PC GR per 14,520 linear ft. of row per 

season. (3) Do not apply within 75 days of 

harvest.

Granular

(EPA Reg 

No. 9198-

183)

Golf Course Tractor drawn 

equipment only 43.5 87 12 N/A

Apply one application in the spring or at first 

indication of disease If disease is severe or 

reappears retreat 3 to 4 weeks later After 

application immediately irrigate with' 1/4 

inch water Mowing may not occur in treated 

area until one day after application

Granular

(EPA Reg 

No. 9198-

227)

Golf Course Tractor drawn 

equipment only 21.8 87.12 N/A

Do not make more than one application at the 

HIGH rate (291 Ibs. product/acre) per season 

except for golf course greens and tees. 

Repeat applications at the HIGH rate on 

greens and tees must not be made sooner 

than 14 days. Repeat applications at the 

LOW rate (145 Ibs. product/acre) per season 

must not be made sooner than 7 days.

*Single applications must not exceed 43.56 

Ibs. ai/A, and total seasonal applications 

must not exceed 87.12 Ibs. ai/A.

Granular

(EPA Reg 

No. 10404-

37)

Turf

Ground application

Aerial not prohibited

handheld not prohibted

32.67 N/S N/A

NOT FOR USE on turf being grown for sale 

or other commercial use as sod, or for 

commercial seed production or for research 

purposes.

Chemigation prohibited
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TableA.6.1. Proposed Use Patterns and Formulations Assessed

Formulation Use Sites Application 

Equipment

PCNB Max 

Application Rates

(lbs ai/A)

Max rate per 

crop season 

(lb ai/A)

REI Application directions2

Granular

(EPA Reg 

No. 34704-

1087)

Golf courses Tractor drawn 

equipment only 43.5 87 12 N/A

Apply one application in the spring or at first 

indication of disease If disease is severe or 

reappears retreat 3 to 4 weeks later After 

application immediately irrigate with' 1/4 

inch water Mowing may not occur in treated 

area until one day after application
Page 46 of 55

Attachment 7: PCNB DFR Waiver Criteria

In accordance with 40CFR158, DFR data are required for all occupational (e.g., crop, nursery, 

greenhouse use sites) or residential (e.g., ornamental and vegetable gardens, pick your own 

farms, retail tree farms) uses that could result in post-application exposure to foliage. In the 

absence of chemical-specific DFR data, EPA uses default values. The 2012 Standard Operating 

Procedures for Residential Pesticide Exposure Assessment includes an analysis of a number of 

DFR studies, which resulted in the selection of a revised default values for the fraction of the 

application rate available for transfer after a foliar application (FAR). This value is based on an 

analysis of 19 DFR studies. Since that time, the Agricultural Re-entry Task Force has submitted 

information (MRID 49299201) that corrects an application rate error made in the original 

submission of “ARF039 – Determination of Dermal and Inhalation Exposure to Reentry Workers 

During Chrysanthemum Pinching in a Greenhouse” (EPA MRID 45344501). As a result of this 

submission, the default value of 25% was not changed as it still reflects a high-end, conservative 

value. However, it is important to note that the range of FAR values was revised from 2% - 89% 

to 2% - 47%. In the data, a large range of transferability is observed and this variability can 

potentially be attributable to many factors such as active ingredient; formulation; field conditions 

in the studies; weather conditions (e.g., humidity); or many other difficult to quantify factors. 

Although witnessed across multiple chemicals, this range in FAR values is not expected when 

considering DFR data for a single chemical. Because DFR data are not available for PCNB, 

EPA is using the default value of 25%. Although there may be a small degree of uncertainty in 

the use of the default DFR value for PCNB (i.e., there is a small chance that the FAR value may 

exceed the applicable default value), it is likely that the health-protective aspects of EPA’s 

occupational post-application assessment methodology will more than compensate for this 

potential uncertainty. For example, when assessing residential and occupational postapplication exposure to gardens and ornamentals, EPA assumes the following: exposures occur 

to zero-day (i.e., day of application ) residues every day of the assessed exposure duration (i.e., 

EPA assumes that no dissipation or degradation occurs, it doesn’t rain, etc); individuals perform 

the same post-application activities performed in the transfer coefficient study day after day (e.g., 

weeding, harvesting, pruning, etc.); and individuals engage in these post-application activities for 

a high-end amount of time every day (represented by data reflecting time spent gardening based 

on survey data).

Given the conservatisms discussed above and the potential compounding nature of these 

conservatisms, EPA is able to rely upon the calculated exposure estimates with confidence that 

exposure is not being underestimated. 

Since the highest estimated occupational post-application exposure using default DFR values for 

PCNB is not minimal in comparison to the level of concern (i.e., the calculated MOE is not 

greater than 2 times higher than the level of concern, MOE = 17 compared to the LOC of 100); 

HED recommends that the 40CFR DFR data be required. Submission of these data will facilitate
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any necessary exposure assessments refinements and further EPA’s general understanding of the 

availability of dislodgeable foliar pesticide residues.

Attachment Table 7.1 Post-application Exposure and Risk Estimates to Support the DFR Waiver Criteria

Crop

Application 

Rate

(lb ai/acre)

Activity

Transfer 

Coefficient 

(cm2/hr)

MOE

Nursery 

Crop/Ornamentals 32.67

Hand Harvesting, Hand 

Pruning, Scouting, Container 

moving, Hand Weeding, 

Transplanting, Grafting, 

Propagating, Pinching, 

Tying/Training

230 140

Irrigation (hand set) 1900 17

Potatoes 2.5

Hand Weeding 70 6100

Scouting 210 2000

Irrigation (hand set) 1900 230
Page 48 of 55

Attachment 8. Residue Chemistry Data Needs for Registration Review of PCNB

Table A.8.1 Residue Chemistry Data Needs for Registration Review of PCNB1.

GLN: Data 

Requirements

40 CFR 

Tolerance 

(ppm)

RED Data Requirements Scoping Data Requirements

Were 

Additional 

Data 

Requested in 

the RED?

References

MRID

Are 

Additional 

Data 

Needed?

Comments

860.1200: Directions for 

Use N/A Yes N/A Yes

EPA Reg. No. 100-823 includes an extensive list of crops that can be rotated 

within 12 months of field treatments. The label should be revised to indicate that 

only registered crops can be rotated. If the Registrant wishes to include additional 

crops for rotation on the label, these crops should be identified and the 

corresponding rotational field trial data will be needed.

EPA Reg. Nos. 5481-8992 and 5481-8988 include the following statement, “Do 

not plant root crops in PCNB treated fields within 12 months of the last 

application of PCNB unless PCNB is registered for use on those crops.” The 

planting of unregistered crops in treated fields within 12 months is not limited to 

root crops. The labels should be revised to indicate the following, “Do not plant 

crops in PCNB treated fields within 12 months of the last application of PCNB 

unless PCNB is registered for use on those crops.” 

EPA Reg. Nos. 5481-8992, 5481-8988, and 100-823 restrict the feeding or grazing 

of cotton foliage by livestock. This language is not enforceable and should be 

removed from the labels. Cotton gin byproduct field trial data are needed. 

HED notes that granular field trial data are not available for dry, lima, and snap 

beans and should be submitted as part of Registration Review. Alternatively, EPA 

Reg. Nos. 100-823 and 5481-8988 could be revised to remove applications to 

beans. 

HED notes that granular field trial data are not available for bell pepper, non-bell 

peppers, and tomatoes and should be submitted as part of Registration Review. 

Alternatively, EPA Reg. No. 5481-8988 can be revised to remove applications to 

peppers and tomatoes. 

HED notes that field trial data are not available for soybean. These data should be 

submitted as part of Registration Review. Alternatively, the labels could be 
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Table A.8.1 Residue Chemistry Data Needs for Registration Review of PCNB1.

GLN: Data 

Requirements

40 CFR 

Tolerance 

(ppm)

RED Data Requirements Scoping Data Requirements

Were 

Additional 

Data 

Requested in 

the RED?

References

MRID

Are 

Additional 

Data 

Needed?

Comments

revised to prohibit the direct application of PCNB to soybeans, and field trials 

would not be required. 

860.1300: Plant 

Metabolism N/A Yes

42222101 

42482701 

42482702

Yes

The nature of the residue in plants is not adequately understood. Additional data 

are required to upgrade Amvac’s existing plant metabolism studies on peanuts, 

cabbage, and potatoes. In considering all three of Amvacs’ previously submitted 

plant metabolism studies, the Agency (D184350 and D181195, J. Abbotts, 

4/16/96) noted that the early metabolites in peanut, potato, and cabbage are 

similar, and the HPLC profiles of polar metabolites are also similar for these 

crops. Provided a new acceptable metabolism study is completed on potato or 

cabbage, including identification of the Unknown metabolites D and H, the 

Agency would be willing to conclude that the nature of the residue in plants was 

adequately understood. These studies should be submitted as part of Registration 

Review.

860.1300: Livestock 

Metabolism N/A Yes

41303101 

41303301 

41823601 

41839701

Yes

The nature of the residues in livestock is not adequately understood. The Agency 

concluded that additional data and information are needed to upgrade the available 

ruminant and poultry metabolism studies submitted by Amvac. However, after 

considering the age of the samples from Amvac’s ruminant and poultry 

metabolism studies, HED (J. Abbotts, 4/16/96) recommended that Amvac should 

submit new livestock metabolism studies. Ruminant and poultry metabolism 

studies should be submitted as part of Registration Review.

860.1340: Residue 

Analytical Methods -

Plant commodities

N/A No 41870204 No

No additional data are needed at this time. Adequate analytical methods are 

available to determine residues of PCNB, PCA, PCTA, PCB, HCB, and TCNB in 

plant commodities. 

860.1340: Residue 

Analytical Methods -

Livestock commodities

N/A Yes -- Yes

As part of Registration Review, the need for tolerances for residues in livestock 

commodities will be considered. If tolerances are recommended, a tolerance 

enforcement method will be needed to analyze for the residues of concern in 

livestock commodities. It is the recommendation of the Agency that since all the 

identified metabolites of PCNB are of concern, a radiovalidated common moiety 

method should be developed by the registrant, if needed. The registrant should 

also make sure that any future submission clearly states the levels of Total 

Radioactive Residue (TRR) for PCNB, PCA, and PCTA. 

860.1360: Multiresidue 

Methods N/A No -- No No additional data are required at this time. The Agency has determined that PCNB, PCA, MPCPS, PCB, and HCB are completely recovered through PAM 
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Table A.8.1 Residue Chemistry Data Needs for Registration Review of PCNB1.

GLN: Data 

Requirements

40 CFR 

Tolerance 

(ppm)

RED Data Requirements Scoping Data Requirements

Were 

Additional 

Data 

Requested in 

the RED?

References

MRID

Are 

Additional 

Data 

Needed?

Comments

Vol. I, Methods 302, 303, and 304. No additional data are required (D. Edwards, 

8/1/86).

860.1650: Analytical 

Reference Standards NA Yes -- No

Analytical standards are currently available in EPA’s National Pesticide Standards 

Repository (NPSR) for PCNB (expires 4/30/2022), PCA (expires 9/1/2021), and 

PCTA (expires 4/30/2020) (email communication between G. Verdin and J. Van 

Alstine, 12/7/2015). 

860.1380: Storage 

Stability Data N/A Yes 41870204 Yes

Storage stability data should be submitted as part of Registration Review to 

support Amvac’s cottonseed, peanut, potato, and tomato processing studies. 

Additionally, any field trial or processing studies submitted as part of Registration 

Review should be supported by adequate storage stability data. 

860.1500: Crop Field Trials

Potato 0.1 Yes 41870208 Yes

An additional 35 field trials are required for potatoes and should be submitted as 

part of Registration Review. These trials should be conducted with 10% G and 2 

lb/gal EC formulations to match previously submitted data. Two sets of trials are 

required for each formulation, one set of pre-plant incorporated (PPI) field trials (9 

trials per formulation) and one set of in-furrow application field trials (9 trials for 

the 10% G formulation and 8 trials for the 2 lb/gal EC formulation). The field 

trials for each formulation and application method should be conducted in NAFTA 

Growing Zones 1 (1 field trial), 2 (1 field trial), 5 (2 field trials), 9 (1 field trials), 

and 11 (4* field trials). *For the in-furrow 2 lb/gal EC formulation, 3 trials are 

required in NAFTA Growing Zone 11. 

Garlic 0.1 Yes -- Yes

Amvac has not submitted field trial data on garlic. The original garlic data were 

submitted by the Olin Chemical Company. Field trial data on garlic should be 

submitted by Amvac as part of Registration Review in accordance with 860.1500. 

Broccoli 0.1 Yes16 41870201 Yes

An additional 7 field trials are required for broccoli and should be submitted as 

part of Registration Review. These trials should all be conducted in NAFTA 

Growing Zone 10, as follows: 1) using a 75% WP formulation at 30 lb ai/A as a

broadcast PPI application (1 field trial) and as a banded application (1 field trial); 

2) using a 75% WP formulation at 4.5 lb ai/100 gal. in soil drench application with 

a PHI > 72 days (3 field trials); and 3) using a 10% G formulation at 30 lb ai/A in 

broadcast PPI application at transplant with a PHI > 72 days (1 field trial) and as a 

banded application with a PHI > 72 days (1 field trial). 
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Table A.8.1 Residue Chemistry Data Needs for Registration Review of PCNB1.

GLN: Data 

Requirements

40 CFR 

Tolerance 

(ppm)

RED Data Requirements Scoping Data Requirements

Were 

Additional 

Data 

Requested in 

the RED?

References

MRID

Are 

Additional 

Data 

Needed?

Comments

Cabbage 0.1 No 41870202 No No additional data are required at this time. 

Collards 0.2 No 00158795 No No additional data are required at this time. 

Kale 0.2 No 00158795 No No additional data are required at this time. 

Mustard Greens 0.2 No 00158795 No No additional data are required at this time. 

Beans 0.1 Yes

41870204 

41870205 

41870209

Yes

Dry Beans: An additional 8 field trials are required for dry beans and should be 

submitted as part of Registration Review. These trials should be conducted with 2 

lb/gal EC (4 field trials) and 75% WP formulations (4 field trials) to match 

previously submitted data. The field trials for each formulation should be 

conducted in NAFTA Growing Zones 5 (2 field trials), 7 (1 field trial), and 8 (1 

field trial). 

Lima Beans: An additional 6 field trials are required for lima beans and should be 

submitted as part of Registration Review. These trials should be conducted with 2 

lb/gal EC (3 field trials) and 75% WP formulations (3 field trials) to match 

previously submitted data. The field trials for each formulation should be 

conducted in NAFTA Growing Zones 2 (2 field trials) and 11 (1 field trial). 

Snap Beans: An additional 12 field trials (6 per formulation; 75% WP and 2 lb/gal 

EC) are required for snap beans and should be submitted as part of Registration 

Review. The available Amvac snap bean field trial data are not adequate. No 

tests were conducted in EPA Region 5. In addition, different post-treatment 

intervals (7, 10, 14, or 20 days) were utilized at each test site, resulting in 

substantial differences in the residue values. The additional field trials should be 

conducted in the NAFTA growing regions specified in OSCPP 860.1500. 

HED notes that granular data are not available for dry, lima, and snap beans and 

should be submitted as part of Registration Review. Alternatively, EPA Reg. Nos. 

100-823 and 5481-8988 could be revised to remove applications to beans. 

Soybeans (seed, forage, 

and hay) 0.02 Yes None Yes

HED notes that the soybean commodity tolerances appear to be established based 

on seed treatment data. Seed treatment uses of PCNB are no longer registered. 

Field trial data are required reflecting the use of PCNB on soybeans at the 

maximum application rate. Alternatively, the labels could be revised to prohibit 
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Table A.8.1 Residue Chemistry Data Needs for Registration Review of PCNB1.

GLN: Data 

Requirements

40 CFR 

Tolerance 

(ppm)

RED Data Requirements Scoping Data Requirements

Were 

Additional 

Data 

Requested in 

the RED?

References

MRID

Are 

Additional 

Data 

Needed?

Comments

the direct application of PCNB to soybeans, and field trials would not be required. 

The need for this tolerance should be considered as part of Registration Review. 

Peppers 0.1 Yes 41870207 Yes

The Amvac pepper field trial data are not adequate based on the geographic 

representation of the field trials. An additional 6 bell pepper field trials (3 per 

application method) and 4 non-bell pepper field trials (2 per application method) 

should be submitted as part of Registration Review. The bell pepper field trials 

should be conducted in NAFTA Growing Zones 5 (1 trial) and 10 (2 trials) using 

each application type (in-furrow and soil drench) for a total of 6 field trials. 

Additionally, 2 field trials must also be conducted on non-bell peppers using each 

application type (in-furrow and soil drench) for a total of 4 additional field trials.

HED notes that granular data are not available for bell and non-bell peppers and 

should be submitted as part of Registration Review. Alternatively, EPA Reg. No. 

5481-8988 can be revised to remove applications to peppers. 

Tomatoes 0.1 Yes 41870210 Yes

The Amvac tomato field trial data are not adequate based on the number and 

geographic representation of the submitted field trials. An additional 14 tomato 

field trials are required and should be submitted as part of Registration Review. 7 

field trials should be completed using the soil drench application method and 7 

field trials should be completed using the in-furrow application method. The field 

trials for each application method should be conducted in NAFTA Growing Zones 

1 (1 field trial), 3 (1 field trial), and 10 (5 field trials). 

HED notes that granular data are not available for tomatoes and should be 

submitted as part of Registration Review. Alternatively, EPA Reg. No. 5481-8988 

can be revised to remove applications to tomatoes. 

Cottonseed 0.1 Yes 41870203 Yes

The Amvac cotton field trial data are not adequate based on the number of crop 

field trials and geographic representation. An additional 12 field trials (4 per 

formulation/application type) should be submitted as part of Registration Review. 

The field trials should be conducted in NAFTA Zones 2 (1 trial) and 8 (3 trials) 

with each formulation-application scenario (10% G in in-furrow application, 10% 

G in banded application, and EC formulation in in-furrow application).
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Table A.8.1 Residue Chemistry Data Needs for Registration Review of PCNB1.

GLN: Data 

Requirements

40 CFR 

Tolerance 

(ppm)

RED Data Requirements Scoping Data Requirements

Were 

Additional 

Data 

Requested in 

the RED?

References

MRID

Are 

Additional 

Data 

Needed?

Comments

Additionally, the feeding or grazing restriction for cotton foliage by livestock is 

not enforceable and should be removed from the labels. At least 12 field trials (6 

per formulation type) for cotton gin byproducts data are required and should be 

submitted as part of Registration Review. The cotton must be harvested by 

commercial equipment (stripper and mechanical picker) to provide an adequate 

representation of plant residue for the ginning process. At least three field trials for 

each type of harvesting (stripper and picker) are needed, for a total of six field 

trials per application formulation/type. Current labels include flowable and 

granular formulations with in-furrow applications. The submitted data should 

reflect the use pattern for each formulation type. 

Peanuts 1.0 Yes 418702062

42718601 Yes

Amvac’s peanut field trial data are not adequate based on the number of crop field 

trials and geographic representation. A total of 30 additional field trials are 

needed for Registration Review. An additional 9 field trials should be conducted 

with the 10% G formulation in NAFTA Zones 2 (7 field trials), 3 (1 field trial), 

and 8 (1 field trial). An additional 10 field trials should be conducted with the 

75% WP formulation in NAFTA Zones 2 (7 field trials), 3 (1 field trial), 6 (1 field 

trial), and 8 (1 field trial). An additional 11 field trials should be conducted with 

the 75% EC formulation in NAFTA Zones 2 (8 trials), 3 (1 field trial), 6 (1 field 

trial), and 8 (1 field trial).

Crops with Seed 

Treatment Uses None Yes 41758201 41871301 No

HED notes that the HED Revised RED Chemistry Chapter (Memo, S. Kinard, 

12/14/2004, D291280) indicated that data were required depicting residues of 

PCNB, PCA, MPCPS, PCB, and HCB in/on RACs of barley, corn, oats, peas, rice, 

safflower, sorghum, sugar beets, and wheat grown from seed treated with PCNB at 

the maximum labeled rate. Since seed treatment uses are no longer registered, 

these data are not needed at this time. 

Ginseng None Yes -- No

HED notes that the HED Revised RED Chemistry Chapter (Memo, S. Kinard, 

12/14/2004, D291280) indicated that PCNB residues were detected in samples of 

ginseng taken by FDA for monitoring purposes. The HED Revised RED 

Chemistry Chapter (Memo, S. Kinard, 12/14/2004, D291280) included a data 

requirement that residue data for ginseng should be generated in the representative 

countries and tolerance should be proposed. Currently there are no ginseng uses 

on the labels, so these data are not needed at this time.

860.1520: Processed Food/Feed
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Table A.8.1 Residue Chemistry Data Needs for Registration Review of PCNB1.

GLN: Data 

Requirements

40 CFR 

Tolerance 

(ppm)

RED Data Requirements Scoping Data Requirements

Were 

Additional 

Data 

Requested in 

the RED?

References

MRID

Are 

Additional 

Data 

Needed?

Comments

Beans, cannery waste None No 41975804 No Bean cannery waste is no longer a regulated commodity.

Cottonseed None Yes 41975801 Yes

To upgrade Amvac’s cottonseed processing study, data are needed depicting the 

frozen storage stability of residues (PCNB, PCA, MPCPS, PCB and HCB) in 

processed cottonseed fractions. Cottonseed processed fractions were stored frozen 

for 29-232 days prior to analysis. These data should be submitted as part of 

Registration Review. 

Peanut None Yes 41975802 Yes

To upgrade Amvac’s peanut processing study, data are needed depicting the 

frozen storage stability of residues (PCNB, PCA, MPCPS, PCB and HCB) in 

processed peanut fractions. Peanut processed fractions were stored frozen for 9-

204 days prior to analysis. These data should be submitted as part of Registration 

Review. 

Potato None Yes 41975803 Yes

To upgrade Amvac’s potato processing study, data are needed depicting the frozen 

storage stability of residues (PCNB, PCA, MPCPS, PCB and HCB) in processed 

potato fractions. Potato processed fractions were stored frozen for 8-218 days 

prior to analysis. These data should be submitted as part of Registration Review. 

Soybean None Yes -- Yes

A soybean processing study is needed. Alternatively, the registrant could prohibit 

direct applications to soybeans, in which case a soybean processing study would 

not be required. These data should be submitted as part of Registration Review if 

applications to soybeans are not prohibited. 

Tomato None Yes 41975805 Yes

To upgrade Amvac’s tomato processing study, data are needed depicting the 

frozen storage stability of residues (PCNB, PCA, MPCPS, PCB and HCB) in 

processed tomato fractions. Tomato processed fractions were stored frozen for 63-

227 days prior to analysis. These data should be submitted as part of Registration 

Review. 

860.1480: Meat, Milk, 

Poultry, and Eggs None Yes -- Yes

As part of Registration Review, the need for tolerances for residues in livestock 

commodities will be considered. Amvac has not submitted ruminant and poultry 

feeding studies and these data may be required as part of Registration Review. 

860.1400: Water, Fish, 

and Irrigated Crops NA NA -- NA NA

860.1460: Food 

Handling NA NA -- NA NA
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Table A.8.1 Residue Chemistry Data Needs for Registration Review of PCNB1.

GLN: Data 

Requirements

40 CFR 

Tolerance 

(ppm)

RED Data Requirements Scoping Data Requirements

Were 

Additional 

Data 

Requested in 

the RED?

References

MRID

Are 

Additional 

Data 

Needed?

Comments

860.1850: Confined 

Rotational Crops NA No 42599201 No

Amvac has not submitted adequate confined rotational crop data; however, the 

ChemSAC determined that based on all available data, PCNB-treated crops should 

only be rotated to labeled crops (6/18/03 Minutes). Additional confined rotational 

crop data are not required at this time.

860.1900: Field

Rotational Crops None Yes -- Yes

The ChemSAC determined that based on all available data, PCNB-treated crops 

should only be rotated to labeled crops (6/18/03 Minutes). Field accumulation 

studies on rotational crops are needed during Registration Review. 

1 Data requirements were initially identified in Table B2 of Memo, S. Kinard, 14-DEC-2004; D291280.

2 As all nutmeat samples from Amvac’s field trials reported in MRID 41870206 were ground with the shells before analysis, the residue data from these samples are considered 

invalid and were not reviewed.