2

Dichlobenil Preliminary Work Plan – Table of Contents

Overview 3

Anticipated Data Needs 4

Statutory and Regulatory Authority 5

Chemical Facts 5

Use and Usage Information 6

Recent Actions 7

Anticipated Risk Assessments for Registration Review 7

Timeline 9

Next Steps 10

Appendix – Additional Areas Considered in Dichlobenil’s Registration Review 11

References:

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

based on the following documents:

1. EFED Registration Review Problem Formulation for Dichlobenil, dated April 26, 2012.

2. Dichlobenil. Human Health Assessment Scoping Document in Support of Registration 

Review, dated May 16, 2012.

3. BEAD Chemical Profile for Registration Review: Dichlobenil, dated February 6, 2012.

4. Dichlobenil: Review of Human Incidents, dated February 14, 2012.

5. Dichlobenil. Recommendation for the residue of concern in drinking water, dated March 

14, 2012.

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

in the docket EPA-HQ-OPP-2012-0395 at http://www.regulations.gov.
3

OVERVIEW:

The docket for dichlobenil is now open, initiating the first public comment period for this 

registration review (docket number EPA-HQ-OPP-2012-0395). This case includes the following 

active ingredients: dichlobenil. Dichlobenil is a pre-emergent herbicide registered for use to 

control grasses and broadleaf weeds in a variety of agricultural and non-agricultural use sites. 

Dichlobenil acts by inhibiting cell wall synthesis. This Preliminary Work Plan (PWP) document 

explains what EPA's Office of Pesticide Programs knows about dichlobenil, highlighting 

anticipated data and assessment needs, identifying the types of information that would be 

especially useful to the Agency in conducting the review, and providing an anticipated timeline 

for completing dichlobenil’s review.

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

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

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

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

dichlobenil. The Agency encourages all interested stakeholders to review the PWP and 

Appendix and to provide comments and additional information that will help the Agency’s 

decision-making process for this chemical. In addition to general areas on which persons may 

wish to comment, there are some areas identified in the PWP and Appendix about which the 

Agency specifically seeks comments and information. Interested stakeholders could include: 

environmental non-profit or interest groups; pesticide manufacturers; agricultural labor or 

commodity groups; commercial, institutional, residential, and other users of pesticides; or the 

public at large.

The PWP begins by listing the anticipated data needs for dichlobenil. Next, it discusses the 

statutory and regulatory authority for Registration Review. Then the document provides 

dichlobenil’s chemical facts, use and usage information, recent actions, the anticipated risk 

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

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

Registration Review along with some additional chemical case-specific information.
4

ANTICIPATED DATA NEEDS:

The table below summarizes anticipated data needs for dichlobenil. For additional discussion of 

the anticipated data needs, see the EFED Registration Review Problem Formulation for 

Dichlobenil, dated April 26, 2012 and Dichlobenil. Human Health Assessment Scoping 

Document in Support of Registration Review, dated May 16, 2012.

Anticipated Data Needs for Dichlobenil’s Registration Review

Guideline 

Number Study Title Test Material

Estimated 

Timeframe

(Months from 

receipt of DCI)

835.1230 Leaching and Adsorption/Desorption1 BZZ2; BAM3 12 

835.4100 Aerobic Soil Metabolism TGAI 24

835.4300 Aerobic Aquatic Metabolism1 BAM 24

835.6200 Aquatic Field Dissipation4 TGAI; BAM 12

850.1075 Fish Acute Toxicity Test (Freshwater) BZZ 12

850.1350 Mysid Chronic Toxicity Test TGAI 12

850.1400 Fish Early Life-Stage Toxicity Test (Freshwater) TGAI 12

850.2100 Avian Acute Oral Toxicity Test (Passerine) TGAI 12

850.2300 Avian Reproduction Test TGAI 24

850.4150 Terrestrial Plant Toxicity: Tier II Vegetative 

Vigor TGAI 12

850.4400 Aquatic Plant Growth: Tier II Vascular Plants BZZ 12

860.1340

Independent Laboratory Validation for the 

Analytical Method for enforcement of tolerances 

(ruminant commodities)

TGAI; BAM 12

Special 

Study Evaluation of Olfactory Toxicity TGAI; BAM 24

870.7800 Immunotoxicity TGAI 12

The study listed below was previously required through a generic data call-in (GDCI-027401-16334), 

issued in March 1987, and is still outstanding. This study is listed in this document as background; it

will NOT be included in the anticipated Registration Review DCI as it is already required through the 

earlier DCI.

860.1520 Processing Study for Grape TEP; BAM Past Due

TGAI = technical grade active ingredient; TEP = typical end-use product

 1 A study for BAM has been submitted and is undergoing review. A new study may be needed depending on the 

outcome of the review.

2 A dichlobenil aquatic degradate 4-chloro-2(3H) benzoxazolone (BZZ). 3 The common metabolite/degradate of dichlobenil and the fungicide fluopicolide, 2,6-dichlorobenzamide (BAM). 4 Only the analytical detection method is needed. An acceptable method (MRID 45321801) has been received and 

reviewed by the Agency. However, an independent laboratory validation of the method is expected to be needed 

before this requirement can be considered satisfied.
5

STATUTORY AND REGULATORY AUTHORITY:

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

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

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

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

on product labeling. The registration review program is intended to make sure that, as the ability 

to assess risk evolves and as policies and practices change, all registered pesticides continue to 

meet the statutory standard of no unreasonable adverse effects to human health or the 

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

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

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

program is provided on EPA’s website5

.

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

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

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

registration. The regulations governing registration review begin at 40 CFR 155.40. The 

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

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

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

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

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

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

the registration review of dichlobenil.

DICHLOBENIL CHEMICAL FACTS:

PC code 027401

Case Number 0263

CAS Number 1194-65-6

Year first registered 1964

Pesticide Type Herbicide

Chemical class Benzonitrile

Reregistration Eligibility 

Decision (RED)

October 1998

Cumulative group None

40 CFR Citation Tolerances for dichlobenil are established in 40 CFR § 180.231.

Dual-use Conventional pesticidal uses only.

Pesticide Re-evaluation 

Division, Chemical 

Review Manager

Eric Miederhoff; miederhoff.eric@epa.gov; (703) 347-8028

Registration Division, 

Product Manager

Kable Davis; davis.kable@epa.gov; (703) 306-0415

 5 http://www.epa.gov/oppsrrd1/registration_review/
6

USE AND USAGE INFORMATION:

Please see the BEAD Chemical Profile for Registration Review: Dichlobenil, dated February 6, 

2012 in the registration review docket for more details.

Summary of Use Dichlobenil is a pre-emergent herbicide registered to control 

grasses and broadleaf weeds in a variety of agricultural and nonagricultural use sites. Dichlobenil acts by inhibiting cell wall 

synthesis. 

Use Sites Agricultural use sites include: apples, grapes, cherries, caneberries, 

blueberries, pears, plant nurseries, shelterbelts, nut trees, and other 

crops such as filberts, huckleberries, laurel, rhubarb, and 

strawberries.

Non-agricultural use sites include: In and around ornamental 

plantings, drain lines, drains, irrigation supply systems, sewage 

system, waste water systems, sewer lines, cesspools, storm sewers, 

non-crop areas, military installations, buildings, roadways, rightsof-way, roadsides, rail yards, industrial sites, asphalt paving, 

parking lots, walks, driveways, parking areas, pre-paving treatment, 

sidewalks, paved areas, fencerows, and vinyl swimming pool liners.

Summary of Usage Limited data are available for dichlobenil’s use on specific crops. 

The Agency estimates that annual agricultural usage averaged 5,000 

pounds of active ingredient (A.I.) treating an average of 2,000 acres 

for the years 2001-2010.

Non-agricultural usage of dichlobenil appears to be greater than 

agricultural usage. Major non-agricultural uses include turf (2006 

national use data; 9,881 pounds), rights of way (data for CA only;

9,500 pounds), sewage systems (2008-2010 data for CA only; 8,400 

pounds), and nurseries/greenhouses (2006 national use data; 4,024 

pounds). 

Formulation Type(s) Dichlobenil is formulated as microencapsulated, wettable powder, 

granular, water soluble packages, and soluble concentrate.

Application Method(s) Products can be applied by aerosol cans, handheld sprayers, 

foggers, and mechanical sprayers.

Technical Registrant(s) Chemtura Corporation and PBI Gordon Corporation

No. of Registrations 19 Section 3 products6 and 1 Section 24(c) product

Restricted Use No

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

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

 6 Section 3 product labels can be obtained from the Pesticide Product Label System (PPLS) website 

(http://oaspub.epa.gov/pestlabl/ppls.home).
7

• Certain dichlobenil labels are unclear with respect to the parameters for residential 

applications to recreational areas: In the absence of clear label information, EPA expects 

to approximate these parameters in order to conduct a quantitative residential risk 

assessment for dichlobenil. The Agency will work with registrants to clarify the

dichlobenil product labels.

• Dichlobenil labels are required to have language restricting dichlobenil use in confined or 

enclosed areas. Certain dichlobenil labels need to be amended to include these 

restrictions. The Agency will work with registrants to amend the relevant dichlobenil 

product labels appropriately.

• Confirmation of the following label information: sites of application; formulations;

application methods and equipment; maximum application rates; frequency of 

application, application intervals, and maximum number of applications per season; 

geographic limitations on use.

• Use distribution (e.g., acreage and geographical distribution of relevant use sites).

• Median and 90th percentile reported use rates (lbs ai/1000 sq ft) from usage data –

national, state, and county.

• Application timing (date of first application and application intervals) – national, state, 

and county.

• Usage/use information for non-agricultural uses.

• Typical application interval (days).

• State or local use restrictions.

• Foreign technical registrants not listed above who supply technical dichlobenil to the U.S.

market.

RECENT ACTIONS:

There are no recent actions for dichlobenil.

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW:

The most recent comprehensive human health risk assessment for dichlobenil was completed in 

2008 for an amendment to registration to add new uses. The most recent ecological and 

environmental fate risk assessment was completed in 2008 for the same purpose. Findings and 

conclusions from these risk assessments are summarized in the EFED Registration Review 

Problem Formulation for Dichlobenil, dated April 26, 2012 and Dichlobenil. Human Health 

Assessment Scoping Document in Support of Registration Review, dated May 16, 2012.

During registration review, the Agency anticipates the need to conduct a comprehensive

ecological risk assessment, including an endangered species assessment, for all uses of

dichlobenil. The Agency has limited data on the dichlobenil aquatic degradate 4-chloro-2(3H) 

benzoxazolone (BZZ) and expects to require ecotoxicity and environmental fate studies to 

determine the toxicity of BZZ to aquatic organisms. If BZZ is found to have equal or greater 

toxicity to these organisms than dichlobenil, it will be considered explicitly in the ecological risk 

assessment. 
8

Additionally, the Agency is expects to require data on the ecotoxicity and environmental fate 

properties of the common metabolite/degradate of dichlobenil and the fungicide fluopicolide, 

2,6-dichlorobenzamide (BAM). These data will be used in assessing BAM in the anticipated 

ecological risk assessment. The registration review docket for fluopicolide is scheduled to open 

in early 2013.

For human health, EPA anticipates the need to conduct revised dietary, residential, and 

occupational risk assessments during registration review. BZZ has been identified as a major 

degradate of dichlobenil in water and should be considered as a residue of concern in drinking 

water. Therefore, the Agency plans to conduct an updated drinking water assessment to account 

for the combined exposure from parent dichlobenil and BZZ (using a total toxic residue 

approach). Further, the major metabolite of dichlobenil, BAM, will also be considered, but will 

be evaluated separately because: (1) its toxicity profile is unlike dichlobenil’s, and (2) to 

consider residues resulting from uses of both dichlobenil and fluopicolide. Updated aggregate 

dietary assessments for dichlobenil and BAM may be needed if the updated drinking water 

assessments result in higher estimated drinking water concentrations (EDWCs). 

If toxicological endpoints, points of departure and/or FQPA safety factors are revised (for 

dichlobenil and/or BAM) based on the data that are anticipated to be required for registration 

review, they will be considered in the new assessments. In addition, any significant changes to 

the standard operating procedures or default exposure assumptions will be considered.

The table below summarizes the anticipated registration review risk assessments based on the 

EFED Problem Formulation, HED Scoping Document and the Dichlobenil. Recommendation for 

the Residue of Concern in Drinking Water, dated March 14, 2012.

Anticipated Risk Assessments for Dichlobenil’s Registration Review

Type of Risk Assessment Include? Notes

Ecological and Environmental Fate

Comprehensive ecological 

(species to be assessed include 

terrestrial and aquatic 

organisms), including 

endangered species 

Yes 

Human Health

Dietary

Food Yes

Drinking water Yes

Occupational

Handlers (mixers, loaders, 

applicators)

Yes

Post-application Yes
9

Anticipated Risk Assessments for Dichlobenil’s Registration Review

Type of Risk Assessment Include? Notes

Residential

Handlers Yes

Post-application No Residential post-application exposure to dichlobenil is 

not anticipated. However, label clarification of 

dichlobenil use in recreational areas is needed.

Incidental oral No Residential post-application exposure to dichlobenil is 

not anticipated. However, label clarification of 

dichlobenil use in recreational areas is needed.

Companion animal No Not registered for pet uses.

Recreational No Residential post-application exposure to dichlobenil is 

not anticipated. However, label clarification of 

dichlobenil use in recreational areas is needed.

Other

Aggregate Yes Evaluates the combined risk from dietary and 

residential exposures.

Cumulative No Dichlobenil, BZZ, and BAM are not assumed to have a 

common mechanism of toxicity with other substances.

Tolerances Yes The tolerances for dichlobenil will be modified during 

registration review.

Guidance for Commenters: Additional ecological information requested for this 

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

• Ecological incidents (non-target plant damage and avian, fish, reptilian, amphibian and 

mammalian mortalities) not already reported to the Agency.

• Water quality monitoring data (see Appendix for further details).

TIMELINE:

EPA has created the following estimated timeline for the completion of dichlobenil’s registration

review.

Registration Review for Dichlobenil – Projected Registration Review Timeline

Activities Estimated Date

Opening the Docket

Open Docket and Public Comment Period 2012 – June

Close Public Comment 2012 – August

Case Development

Final Work Plan 2012 – November

Issue DCI 2013 – July – Sept.

Data Submission 2015 – July – Sept.
10

Registration Review for Dichlobenil – Projected Registration Review Timeline

Activities Estimated Date

Open Public Comment Period for Draft Risk Assessments 2017 – Jan. – March

Close Public Comment Period 2017 – April – June

Registration Review Decision

Open Public Comment Period for Proposed Registration Review 

Decision

2017 – July – Sept.

Close Public Comment Period 2017 – Oct. – Dec.

Registration Review Decision and Begin Post-Decision Follow-up 2018

Total (years) 6

NEXT STEPS:

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

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

review of dichlobenil.
11

Appendix – Additional Areas Considered in Dichlobenil’s Registration 

Review

PUBLIC COMMENTS AND FEEDBACK:

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

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

be of particular use.

Trade Irritants:

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

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

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

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

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

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

the nature of the concern. 

Water Quality:

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

under section 303(d) of the Clean Water Act7

. In addition, no Total Maximum Daily Loads 

(TMDL) have been developed for dichlobenil8

. More information on impaired water bodies and 

TMDLs can be found at the Agency’s website9

. The Agency invites submission of water 

quality data for this pesticide. To the extent possible, data should conform to the quality 

standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired 

Water Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and 

Management Process10 in order to ensure they can be used quantitatively or qualitatively in 

pesticide risk assessments.

Standard Operating Procedure: Inclusion of Impaired Water Body and Other Water Quality 

Data in OPP’s Registration Review Risk Assessment and Management Process

11 in order to 

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

Environmental Justice:

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

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

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

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

 7 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

8

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_

group_name=PESTICIDES

9 http://www.epa.gov/owow/tmdl/

10 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm 11 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm
12

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

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

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

exposure compared to the general population.

ENDANGERED SPECIES:

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

conducted for dichlobenil. The ecological risk assessment planned during registration review 

will allow the Agency to determine whether dichlobenil’s use has “no effect” or “may affect” 

federally listed threatened or endangered species (listed species) or their designated critical 

habitats. When an assessment concludes that a pesticide’s use “may affect” a listed species or its 

designated critical habitat, the Agency will consult with the U.S. Fish and Wildlife Service 

and/or National Marine Fisheries Service (the Services), as appropriate.

On January 19, 2011, the Center for Biological Diversity and the Pesticide Action Network 

North America filed a lawsuit in the United States District Court for the Northern District of 

California, against the Environmental Protection Agency (EPA) for allegedly failing to undergo 

consultation with the United States Fish and Wildlife Service and the National Marine Fisheries 

Service regarding the effects of over 350 pesticides, including dichlobenil, on over 200 

endangered and threatened species throughout the United States (Center for Biological Diversity, 

et al. v. EPA, et al., No. C 11-00293 (N.D.Cal.).

ENDOCRINE DISRUPTOR SCREENING PROGRAM:

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

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

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

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

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

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

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

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

taxonomic groups. As part of its most recent registration decision for dichlobenil, EPA reviewed 

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

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

subject to the endocrine screening part of the Endocrine Disruptor Screening Program (EDSP). 

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

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

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

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

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

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

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

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

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 
13

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

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

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

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

which contains 58 pesticide active ingredients and 9 inert ingredients. Dichlobenil was included 

on that list and has been issued an order to conduct the Tier 1 testing. Once all required Tier 1 

and Tier 2 data have been received and reviewed, the endpoints and safety factors used for risk 

assessment purposes will be examined and a new risk assessment performed if necessary. For 

further information on the status of the EDSP, the policies and procedures, the list of 67 

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

website12.

HUMAN STUDIES:

Occupational and Residential

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

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

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

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

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

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

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

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

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

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

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

 12 http://www.epa.gov/endo/