Docket Number; EPA–HQ–OPP–2010-0455

www.regulations.gov

United States Chemical Safety March 2011

Environmental Protection and Pollution Prevention

Agency (7510P)

Naphthenate Salts

(Copper Naphthenate and Zinc Naphthenate) 

Final Work Plan Registration Review 

March 2011
Docket Number; EPA-HQ-OPP-201 0-0455 

www.regulations.gov 

Docket Number: EPA-HQ-OPP-2010-0455 

N aphthenate Salts Final Work Plan 

Registration Review 

Case # 3099 

Approved By: 

Harrigan-Farrelly 

irector, Antimicrobials Division 

Date: 

7 I 

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TABLE OF CONTENTS

Naphthenate Salts (Copper Naphethenate and Zinc Naphethenate) Registration Review Team ......... 4

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

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

IV. TIMELINE............................................................................................................................................12

V. GLOSSARY of TERMS & ABBREVIATIONS ..................................................................................13
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Naphthenate Salts Registration Review Team

Human Health & Environmental Effects 

Nathan Mottl

Srinivas Gowda

Risk Management

Rebecca von dem Hagen

Lance Wormell

Office of General Counsel

Philip Ross
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I. INTRODUCTION

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

Work Plan (FWP) for the registration review of naphthenate salts (copper naphthenate 

and zinc naphthenate). The work plan includes the expected registration review timeline. 

The work plan also addresses public comments received concerning the Preliminary 

Work Plan (PWP) in the Summary Document which was posted in the naphthenate salts

(copper naphthenate and zinc naphthenate) registration review docket, and any other 

comments concerning the initial docket postings. The Summary Document provided 

information on what EPA knows about the pesticide and what additional risk analyses 

and data or information the Agency believes are needed to make a registration review 

decision. 

The Agency is implementing the registration review program pursuant to Section 

3(g) of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and will review 

each registered pesticide every 15 years to determine whether it continues to meet the 

FIFRA standard for registration. Changes in science, public policy and pesticide use 

practices will occur over time. The registration review program is intended to make sure 

that, as the ability to assess risk evolves and as policies and practices change, all 

registered pesticides continue to meet that statutory standard. The public phase of 

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

on this program is provided at: http://www.epa.gov/oppsrrd1/registration_review/.

There are two active ingredients in the naphthenate salts case 3099: copper 

naphthenate (PC Code 023102) and zinc naphthenate (PC Code 088301). Although the 

case name groups these chemicals using the term "naphthenate salts," throughout this 

document and the supporting documents for this case the compounds will be named 

individually as "copper naphthenate" and "zinc naphthenate" to avoid potential confusion. 

The naphthenate salts (copper naphthenate and zinc naphthenate) Preliminary Work Plan 

was published September 29, 2010. The 60-day comment period ended on November 29, 

2010. The Preliminary Work Plan document is available on www.regulations.gov, 

docket number EPA-HQ-OPP-2010-0455.

II. COMMENTS RECEIVED ON THE PRELIMINARY WORK PLAN

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

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

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

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

The comment received during the initial public comment period is described 

below and specifically concerned the confirmatory data required via the post-RED Data 

Call-In Notice (DCI) issued in June 2010. The comment did not affect the data needs, 

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

initially in the PWP. Further, this document makes final the work plan for the 

naphthenate salts (copper naphthenate and zinc naphthenate) registration review process.
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Comment: The commenter expressed concern that the data requirements for 

copper naphthenate will all but eliminate the use of copper naphthenate as a wood 

preservative from the US market. The commenter believes that the economic cost 

of these tests will force the manufacturers to cancel their registrations, leaving a 

void in the wood preservative market that will have a devastating economic effect 

on small producers, contractors, homeowners, ranchers and electric utilities. The 

commenter recommends label language forbidding the use of the product indoors 

and on or around a residence be used to mitigate the need for additional data.

Response: The data about which the commenter is concerned were called in by 

the Agency through the June 2010 post-RED DCI. The Agency does not at this 

time anticipate the need to require any additional data for this registration review 

process. 

III. RISK ASSESSMENT AND DATA NEEDS

Copper naphthenate was first registered with the Agency in 1951. There are 30

registered copper naphthenate products. These are registered for use as a material 

preservative (rope textiles, burlap, canvas products including, nets (excluding fish nets), 

seines, tents, awnings, particle board, insulation board, and other wood base fiber and 

particle materials tarpaulins) and as a wood preservative (lumber, timbers, posts, poles, 

and other wooden members, all exterior wood exposed to moisture or weather, wooden 

boat hulls, piers).

Zinc naphthenate was first registered with the Agency in 1975. There are 10

registered zinc naphthenate products. Zinc naphthenate products are registered for use as 

a wood preservative (foundations, boats, construction posts, docks & piers, door frames, 

doors, fence posts, fences, fencing, end cuts, foundation timbers greenhouse wood and 

stakes, house siding, landscape logs lawn furniture, millwork, planking, planter boxes, 

plywood, poles, porches, posts, pressure treated wood end cut protection, roofs, shakes, 

shingles, sidings, sills, stairs, structural logs, structural lumber; structural timber, 

subflooring, windows and frames) and a material preservative (non-apparel fabrics, 

ropes, fishnets, twine, canvas, burlap and other non-apparel fabric material).

A Reregistration Eligibility Decision (RED) for copper and zinc naphthenate salts 

was issued by EPA in September 2007. As part of the Reregistration process, Data CallIn Notices (DCI) for copper naphthenate and zinc naphthenate were issued in June 2010. 

The naphthenate salts RED can be located at 

http://www.epa.gov/pesticides/reregistration/status.htm.

Human Health Risk Assessment Status and Anticipated Data Needs

The Agency has reviewed all the available information on toxicology and human 

exposure regarding copper and zinc naphthenate and does not anticipate that additional 

data will be needed for this registration review case. 
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Further human health information is available in the document titled “Human 

Health Effects Data for the Copper and Zinc Naphthenate Registration Review 

Decision,” dated July 19, 2010.

Dietary and Drinking Water Assessment

Dietary Exposure

EPA does not anticipate conducting dietary (food) risk assessments because there 

are no registered food use tolerances for the active ingredients, no registered food uses, 

and no indirect food uses. However, a drinking water assessment will be conducted .

Drinking Water Exposure

Copper and zinc naphthenate products are registered for use for treating wood that 

may come in contact with surface water (e.g., docks and piers) and therefore, could 

potentially result in drinking water exposure. The Agency will conduct a drinking water 

assessment during the registration review risk assessment process by modeling

environmental concentrations of copper and zinc naphthenate in surface water as a result 

of the wood preservative uses.

Tolerances

There are no tolerances or exemptions from tolerances for the copper and zinc 

naphthenate active ingredients and no registered food uses. There are inert exemptions 

from tolerances for copper naphthenate. However, inert exemptions from tolerances are 

not addressed in this registration review. 

Aggregate and Cumulative Exposure

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

reliable information concerning exposures to pesticide residues in food and drinking 

water, as well as non-occupational pesticide exposures. Food exposures of concern are 

not anticipated based on the fact that neither copper nor zinc naphthenate are expected to 

be introduced into food, there are no food use tolerances for the active ingredient, no 

registered food uses, and no indirect food uses. The Agency will conduct surface water 

modeling and a drinking water assessment. The Agency expects to conduct a residential 

assessment to examine hand-to-mouth and dermal exposures to children from playsets 

and decks. The Agency will conduct an aggregate assessment that includes both 

residential and drinking water exposure. 

Section 40(b)(2)(D)(v) of FFDCA requires that, when considering whether to 

establish, modify, or revoke a tolerance, the Agency considers “available information” 

concerning the cumulative effects of a particular pesticide’s residues and “other 

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

whether copper and zinc naphthenate has a common mechanism with other compounds; 

consequently a cumulative assessment will not be performed at this time.
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Occupational and Residential Assessment

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

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

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

treated sites after application is complete. Based on the available use information, the 

Agency believes there is potential exposure for occupational handlers (i.e., from 

applications of wood preservatives and textiles) and residential handlers (e.g., 

homeowner wood treatment applications). In addition, the Agency expects there also will 

be exposure from occupational post-application exposures (i.e., workers exposed to wood 

treatment facilities) and residential post-application exposure concerns for children (i.e., 

contact with treated wood playsets and decks). Depending on the outcome of the review 

of the data being called-in through the June 2010 post-RED DCI for copper and zinc 

naphthenate, the Agency anticipates the need to conduct new handler and postapplication assessments for registration review. The EPA also anticipates that 

occupational, residential, and aggregate assessments will be needed to ensure that the 

copper and zinc naphthenate registration review case meets the safety standards 

established by FIFRA and FFDCA, as amended by FQPA.

Hander Exposure

Occupational Handlers

The Agency identified potential occupational handler exposures for copper and 

zinc naphthenate in the 2007 RED. No new uses in addition to those included in the RED 

have been identified during the registration review process. The potential occupational 

handler risk assessments (both short-term (1-30 days) and intermediate-term (>30 days)) 

by scenario that the Agency expects to conduct during registration review include:

• Incorporation into Textiles During Industrial Manufacturing;

• Handler Exposure to Workers at Non-pressure Treatment Facilities (i.e., diptank 

operator, blender/spray operator, and chemical operator);

• Handler Exposure to Workers at Pressure Treatment Facilities (i.e., treatment 

operator and treatment assistant); 

• Handler Exposure to Workers at Commercial Wood/Lumber Facilities; and

• Application to In-service Utility Poles, Pilings, Posts, and Other Standing 

Timbers.

The methods of direct application include liquid pour and liquid pump, low 

pressure spray, brush/roller, non-pressure treatment, pressure treatment, brush, trowel or 

grease gun, and pre-manufactured bandage. 
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Residential Handlers

Residential handler exposure can occur through the application of copper and zinc 

naphthenate preservative coatings via paintbrush or sprayer application. The Agency 

expects to conduct residential handler risk assessments for these scenarios and the 

Agency is likely to conduct a risk assessment only of short-term duration. The short term 

duration was chosen to be assessed because the different scenarios (i.e. methods of 

application) are assumed to be episodic, not daily over the course of a year and would not 

typically exceed 30 days per year.

Postapplication Exposure

Occupational

The Agency identified potential occupational postapplication exposures for 

copper and zinc naphthenate previously in the RED. No new uses in addition to those 

included in the RED have been identified during the registration review process. The 

potential occupational scenarios include:

• Post-application Exposure to Workers at Sawmills/Planer Mills (e.g., grader, trim 

saw operator, millwright, and clean-up); and, 

• Post-application Exposure to Workers at Pressure Treatment Facilities (e.g., tram 

setter, stacker operator, loader operator, supervisor, test borer, and tallyman).

Residential

 The Agency expects that it will need to conduct a residential assessment to 

examine hand-to-mouth and dermal exposures to children from playsets and decks.

Product Chemistry Status and Anticipated Data Needs 

All product chemistry data requirements have been fulfilled for the active 

ingredient naphthenate salts. Therefore, it is anticipated that no additional product 

chemistry data will be needed for copper and zinc naphthenate salts.

For further information please refer to the Summary of Product Chemistry, 

Environmental Fate, and Ecotoxicity Data for the Copper Naphthenate and Zinc 

Naphthenate Salts Registration Review Decision Document, dated July 26, 2010.

Environmental Fate and Ecological Risk Assessment Status and Anticipated Data 

Needs

The Agency does not expect to require additional data through the registration 

review process. The ecological effects data required as a result of the September 2007 

RED for naphthenate salts (copper naphthenate and zinc naphthenate) through the June 

2010 post-RED DCI will be evaluated and used to support the registration review risk 

assessments.
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For further information please refer to the Summary of Product Chemistry, 

Environmental Fate, and Ecotoxicity Data for the Copper Naphthenate and Zinc 

Naphthenate Salts Registration Review Decision Document, dated July 26, 2010.

Endangered Species

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

endangered species determination for naphthenate salts (copper naphthenate and zinc 

naphthenate). The ecological risk assessment planned during registration review will 

allow the Agency to determine whether use of naphthenate salts 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 copper naphthenate and zinc naphthenate, 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 2007 naphthenate salts reregistration eligibility decision, 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), copper 

naphthenate and zinc naphthenate are 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 
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the Administrator may designate.” The EDSP employs a two-tiered approach to making 

the statutorily required determinations. Tier 1 consists of a battery of 11 screening assays 

to identify the potential of a chemical substance to interact with the estrogen, androgen, 

or thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening 

and are found to have the potential to interact with E, A, or T hormonal systems will 

proceed to the next stage of the EDSP where EPA will determine which, if any, of the 

Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to 

identify any adverse endocrine-related effects caused by the substance, and establish a 

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

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

Between October 2009 and February 2010, EPA issued test orders/data call-ins for the 

first group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert 

ingredients. Copper naphthenate and zinc naphthenate are not among the group of 58 

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

Accordingly, as part of registration review, EPA will issue future EDSP orders/data callins, requiring the submission of EDSP screening assays for copper naphthenate and zinc 

naphthenate. For further information on the status of the EDSP, the policies and 

procedures, the list of 67 chemicals, future lists, the test guidelines and the Tier 1 

screening battery, please visit our website: http://www.epa.gov/endo/.
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IV. TIMELINE

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

naphthenate salts (copper naphthenate and zinc naphthenate) registration review case. 

The Agency does not anticipate requiring additional data for this registration review case.

Anticipated Schedule

Activities Estimated Month/Year

Phase 1: Opening the docket

Open Public Comment Period for Naphthenate Salts Docket September 2010-

complete

Close Public Comment Period November 2010-

complete

Phase 2: Case Development

Develop Final Work Plan (FWP) March 2011- complete

Open Public Comment Period for Preliminary Risk Assessments June 2013

Close Public Comment Period August 2013

Phase 3: Registration Review Decision

Open Public Comment Period for Proposed Reg. Review Decision October 2014

Close Public Comment Period January 2015

Final Decision and Begin Post-Decision Follow-up 2015

Total (years) 5

Next Steps

The data being called in as a result of the June 2010 Reregistration DCI will be 

evaluated and used to support the registration review risk assessments for the naphthenate 

salts case.
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V. GLOSSARY of TERMS & ABBREVIATIONS

ai Active Ingredient

AR Anticipated Residue

ASTM American Society for Testing and Materials

AWPA American Wood Preserver’s Association

CBI Confidential Business Information

CFR Code of Federal Regulations

cPAD Chronic Population Adjusted Dose

CSF Confidential Statement of Formula

CSFII USDA Continuing Surveys for Food Intake by Individuals

DCI Data Call-In

DEEM Dietary Exposure Evaluation Model

DFR Dislodgeable Foliar Residue

DNT Developmental Neurotoxicity

DWLOC Drinking Water Level of Comparison

EC Emulsifiable Concentrate Formulation

EDWC Estimated Drinking Water Concentration

EEC Estimated Environmental Concentration

EP End use Product

EPA Environmental Protection Agency

EUP End-Use Product

FDA Food and Drug Administration

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act

FFDCA Federal Food, Drug, and Cosmetic Act

FQPA Food Quality Protection Act

FOB Functional Observation Battery

GENEEC Tier I Surface Water Computer Model

IR Index Reservoir

LC50 Median Lethal Concentration. A statistically derived concentration of a 

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

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

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

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

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

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

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

LOC Level of Concern

LOAEL Lowest Observed Adverse Effect Level

μg/g Micrograms Per Gram

μg/L Micrograms Per Liter

mg/kg/day Milligram Per Kilogram Per Day

mg/L Milligrams Per Liter

MOE Margin of Exposure 

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

submitted studies.

MUP Manufacturing-Use Product

NA Not Applicable

NAWQA USGS National Ambient Water Quality Assessment

NPDES National Pollutant Discharge Elimination System

NR Not Required

NOAEL No Observed Adverse Effect Level

OPP EPA Office of Pesticide Programs

OPPTS EPA Office of Prevention, Pesticides and Toxic Substances

PAD Population Adjusted Dose
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PAIRA Pure Active Ingredient Radiolabelled

PCA Percent Crop Area

PDP USDA Pesticide Data Program

PHED Pesticide Handler's Exposure Data 

PHI Preharvest Interval

phr Pounds Per Hundred

ppb Parts Per Billion

PPE Personal Protective Equipment

ppm Parts Per Million

PRZM/EXAMS Tier II Surface Water Computer Model 

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

Risk Model

RAC Raw Agriculture Commodity

RED Reregistration Eligibility Decision

REI Restricted Entry Interval

RfD Reference Dose

RQ Risk Quotient

RTU Ready to Use

SCI-GROW Tier I Ground Water Computer Model

SAP Science Advisory Panel

SF Safety Factor

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

TGAI Technical Grade Active Ingredient

TEP Typical End-Use Product

USDA United States Department of Agriculture

UF Uncertainty Factor

WPS Worker Protection Standard