Docket Number; EPA–HQ–OPP–2010-0243

www.regulations.gov

United States Chemical Safety October 2010

Environmental Protection and Pollution Prevention

Agency (7510P)

Dichromic Acid

Final Work Plan Registration Review 

October 2010

Docket Number; EPA-HQ-OPP-2010-0243

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TABLE OF CONTENTS

Dichromic Acid Registration Review Team............................................................................................... 4

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

II. COMMENTS RECEIVED ON THE PRELIMINARY WORK PLAN............................................. 6

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

IV. TIMELINE............................................................................................................................................. 9

V. GLOSSARY of TERMS & ABBREVIATIONS ..................................................................................11
Docket Number; EPA-HQ-OPP-2010-0243

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Dichromic Acid Registration Review Team

Human Health & Environmental Effects 

Nathan Mottl

A. Najm Shamim

Risk Management

Rebecca von dem Hagen

Lance Wormell

Office of General Counsel

Philip Ross
Docket Number; EPA-HQ-OPP-2010-0243

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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 dichromic acid. 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 dichromic acid registration review docket, and any other comments 

concerning the initial docket postings. The Summary Document provided information on 

what EPA knows about the pesticide and what additional risk analyses and data or 

information the Agency believes are needed to make a registration review decision. 

The Agency is implementing the registration review program pursuant to Section 

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

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

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

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

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

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

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

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

The dichromic acid Preliminary Work Plan (PWP) (PC Code 068306) was published 

June 23, 2010. The 90-day comment period ended on August 23, 2010. The Preliminary 

Work Plan document is available on www.regulations.gov, docket number EPA-HQOPP-2010-0243.

A pesticide product containing dichromic acid was first registered in 1994. 

Because dichromic acid was registered after November 1984, this ingredient was not 

considered under EPA’s reregistration program. However, a Reregistration Eligibility 

Decision (RED) for chromated arsenicals was completed in 2008. The 2008 RED 

addressed potential exposure and risk from chromium (VI) oxide (also known as

“chromic acid”). Chromic acid and dichromic acid are both created through the same 

chemical processes and composed of chromium in the hexavalent form (Cr(VI)), with 

dichromic acid being a relatively unstable form of chromic acid. Because chromic acid 

and dichromic acid are composed of the same chemical of toxicological significance 

(hexavalent chromium), the Agency intends to incorporate data received in response to 

the chromic acid RED DCI into the risk assessments to be performed for the registration 

review of dichromic acid. The Agency anticipates issuing the chromic acid RED DCI in 

FY2011 and anticipates reviewing any data received in response to the RED DCI prior to 

conducting the registration review risk assessments for dichromic acid. Also, the Agency 

notes that this registration review will be based on updated labels received in response to 

the 2008 chromated arsenicals RED and approved by the Agency in May 2010 for the 

two active registrations. The updated labels reflect mitigation measures outlined in the 

2008 RED.
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II. COMMENTS RECEIVED ON THE PRELIMINARY WORK PLAN

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

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

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

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

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

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

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

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

plan for the dichromic acid registration review process.

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

comment requesting that the lead technical registrant for dichromic acid who is 

not a member of the FESTF (or a company having met its data compensation 

obligations) provide a formal offer-to-pay to FESTF for reliance on their data or 

be required to develop substantially similar data on their own. 

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

information as it conducts the registration review and makes its registration 

review decisions.

III. RISK ASSESSMENT AND DATA NEEDS

Human Health Risk Assessment Status and Anticipated Data Needs

The Agency reviewed the hazard and exposure databases for dichromic acid. As 

a result of this review, EPA confirmed that the data to be required for dichromic acid as a 

result of the September 2008 chromated arsenicals RED are still needed. The studies that 

will be required upon issuance of the RED Data Call-In (DCI) can be found in the 

Agency’s chromated arsenicals RED at http://www.regulations.gov in docket number 

EPA-HQ-OPP-2003-0250. The Agency does not anticipate the need to require any other 

human health data for dichromic acid through the registration review program.

Dietary Assessment

Acute and chronic dietary assessments are not necessary for dichromic acid 

because there are no uses of dichromic acid attributable to the dietary route of exposure.

Because wood preservative use is not expected to result in drinking water 

exposure, a drinking water assessment is not anticipated to be needed. According to the 

RED, “studies of sorption into soils from utility poles, have shown that the release of 

metals into soils/sediments from the base of treated wood, decks or utility poles or from 

the pressure treatment facilities, do not show a high degree of migration, either to 
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groundwater or to the surface. In most cases, after migration of the metals a few meters 

down into soil, these metals attain the background level concentration of soil.”

Tolerances

There are currently no tolerances or exemptions for the requirement of a tolerance 

for dichromic acid.

Occupational and Residential Assessment and Risk

The Agency reviewed all available data associated with dichromic acid and has 

determined that the currently registered uses of dichromic acid may result in occupational 

exposure. An occupational risk assessment for inhalation exposure to Cr(VI) was 

performed in 2008 for the chromated arsenicals RED. The Agency reviewed the 2008 

risk assessment and determined that the data to be called in upon the issuance of the 

chromated arsenicals RED DCI are still needed and does not anticipate the need to 

require any other human health data for dichromic acid through the registration review 

program. Contingent upon the receipt of the data for chromic acid to be required through 

the reregistration process from chromated arsenicals, the Agency may develop new 

occupational inhalation risk assessments for the dichromic acid registration review.

CCA is no longer registered for use on wood intended to be used for decks or play 

sets and the remaining two residential uses (shakes/shingles and permanent wood 

foundations) are not expected to result in significant exposure to dichromic acid. 

Therefore, a residential assessment is not required for these uses.

Aggregate and Cumulative Exposure and Risk

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

reliable information concerning exposures to pesticide residues in food and drinking 

water, and non-occupational pesticide exposures. As previously stated, acute and chronic 

dietary assessments will not be conducted for dichromic acid because there are no uses of 

dichromic acid which would be attributable to the dietary route of exposure. The 

remaining residential uses of dichromic acid are not expected to result in significant

residential exposure. Therefore, no need is anticipated for an aggregate exposure 

assessment. 

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

establish, modify, or revoke a tolerance, the Agency consider "available information” 

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 dichromic acid has a common mechanism with other compounds, consequently a 

cumulative assessment will not be performed at this time.

Anticipated Human Health Data Needs
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EPA confirmed that the data to be required for dichromic acid as a result of the 

September 2008 chromated arsenicals RED are still needed and the Agency does not 

anticipate the need to require any other human health data for dichromic acid through the 

registration review program.

For further information see the document titled, “Summary of Human Health 

Effects Data for the Dichromic Acid Registration Review Decision Document,” dated 

May 27, 2010.

Anticipated Physical/Chemical Property Data Needs

All product chemistry data requirements have been fulfilled for dichromic acid.

Therefore, it is anticipated that additional product chemistry data will not be needed for 

dichromic acid.

For further information see the document titled, Dichromic Acid: Product 

Chemistry/Environmental Fate and Eco-Effects Scoping Document dated May 6, 2010.

Environmental Fate and Ecological Risk Assessment Status and Anticipated Data 

Needs

The Agency reviewed the environmental fate and ecological hazard databases for 

dichromic acid. As a result of this review, EPA confirmed that the data to be required for 

dichromic acid as a result of the chromated arsenicals RED are still needed. The studies 

that will be called in for reregistration can be found in the Agency’s chromated arsenicals 

RED at http://www.regulations.gov in docket number EPA-HQ-OPP-2003-0250. The 

Agency does not anticipate the need to require any additional environmental fate data for 

dichromic acid through the registration review program. 

For further information see the document titled, “Dichromic Acid: Product 

Chemistry/Environmental Fate and Eco-Effects Scoping Document” dated May 6, 2010.

Endangered Species

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

endangered species determination for dichromic acid. The ecological risk assessment 

planned during registration review will allow the Agency to determine whether 

chromium (VI), the chemical of toxicological concern found in pesticide products 

containing dichromic acid (Case 5012) and chromic acid (Case 0132), has “no effect” or 

“may affect” federally listed threatened or endangered species (listed species) or their 

designated critical habitats. Because the chemical of toxicological concern and use 

patterns are the same for chromic acid and dichromic acid, the Agency intends to perform 

a comprehensive endangered species assessment for chromium (VI). When an assessment 

concludes that a pesticide’s use “may affect” a listed species or its designated critical 
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habitat, the Agency will consult with the U.S. Fish and Wildlife Service and/or National 

Marine Fisheries Services (the Services), as appropriate.

Incidents:

In the chromated arsenicals RED only limited incident reports are associated with 

exposure to end-use products containing chromated arsenicals. In contrast, a large body 

of literature exists on the health effects (acute and chronic) in humans of exposure to the 

components of chromated arsenicals, particularly arsenic and, to a lesser degree, 

chromium and copper. Itching, burning rashes, neurological symptoms, and breathing 

problems associated with handling unmarked CCA-treated wood have been reported. Sap 

draining from CCA treated wood stairs has been reported as a potential source of dermal 

and inhalation exposure leading to dermatitis and development of film on the teeth. At 

least one individual reported “ruined” nerves in feet and legs which he attributed to 

exposure to saw dust and fumes from cutting and routing CCA-treated lumber. No new 

incidents have been reported for dichromic acid since the chromated arsenicals RED has 

been completed.

IV. TIMELINE

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

dichromic acid 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 Dichromic Acid Docket June 2010 - complete

Close Public Comment Period August 2010 - complete

Phase 2: Case Development

Develop Final Work Plan (FWP) October 2010

Issue DCI N/A1

Open Public Comment Period for Preliminary Risk Assessments June 2016

Close Public Comment Period September 2016

Phase 3: Registration Review Decision

Open Public Comment Period for Proposed Reg. Review Decision December 2016

Close Public Comment Period March 2017

Final Decision and Begin Post-Decision Follow-up 2017

Total (years) 7 1 As previously discussed in this document, the Agency does not anticipate issuing a DCI for dichromic 

acid through the registration review program; however, additional studies are expected to be submitted as a 

result of the reregistration eligibility decision for chromated arsenicals (Case 0132) and the risk 

assessments for dichromic acid will be conducted once those studies are received.
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Next Steps

The Agency intends to complete a preliminary risk assessment for dichromic acid 

once the studies that will be called-in through the chromated arsenicals post-RED DCI

are received. The Agency anticipates issuing the chromic acid post-RED DCI in 

FY2011.
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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