Federal Register / Vol. 76, No. 105 / Wednesday, June 1, 2011 / Rules and Regulations 31485 

* * * * * 

[FR Doc. 2011–13587 Filed 5–31–11; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 180 

[EPA–HQ–OPP–2010–0268; FRL–8873–9] 

Bromoxynil; Pesticide Tolerances 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: This regulation revises 

established tolerances for residues of 

bromoxynil in or on multiple 

commodities which are identified and 

discussed later in this document. Bayer 

CropScience LLC requested these 

tolerances under the Federal Food, 

Drug, and Cosmetic Act (FFDCA). 

DATES: This regulation is effective June 

1, 2011. Objections and requests for 

hearings must be received on or before 

August 1, 2011, and must be filed in 

accordance with the instructions 

provided in 40 CFR part 178 (see also 

Unit I.C. of the SUPPLEMENTARY

INFORMATION). 

ADDRESSES: EPA has established a 

docket for this action under docket 

identification (ID) number EPA–HQ– 

OPP–2010–0268. All documents in the 

docket are listed in the docket index 

available at http://www.regulations.gov. 

Although listed in the index, some 

information is not publicly available, 

e.g., Confidential Business Information 

(CBI) or other information whose 

disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, is not placed on 

the Internet and will be publicly 

available only in hard copy form. 

Publicly available docket materials are 

available in the electronic docket at 

http://www.regulations.gov, or, if only 

available in hard copy, at the OPP 

Regulatory Public Docket in Rm. S– 

4400, One Potomac Yard (South Bldg.), 

2777 S. Crystal Dr., Arlington, VA. The 

Docket Facility is open from 8:30 a.m. 

to 4 p.m., Monday through Friday, 

excluding legal holidays. The Docket 

Facility telephone number is (703) 305– 

5805. 

FOR FURTHER INFORMATION CONTACT: 

Susan Stanton, Registration Division 

(7505P), Office of Pesticide Programs, 

Environmental Protection Agency, 1200 

Pennsylvania Ave., NW., Washington, 

DC 20460–0001; telephone number: 

(703) 305–5218; e-mail address: 

stanton.susan@epa.gov. 

SUPPLEMENTARY INFORMATION: 

I. General Information 

A. Does this action apply to me? 

You may be potentially affected by 

this action if you are an agricultural 

producer, food manufacturer, or 

pesticide manufacturer. Potentially 

affected entities may include, but are 

not limited to those engaged in the 

following activities: 

• Crop production (NAICS code 111). 

• Animal production (NAICS code 

112). 

• Food manufacturing (NAICS code 

311). 

• Pesticide manufacturing (NAICS 

code 32532). 

This listing is not intended to be 

exhaustive, but rather to provide a guide 

for readers regarding entities likely to be 

affected by this action. Other types of 

entities not listed in this unit could also 

be affected. The North American 

Industrial Classification System 

(NAICS) codes have been provided to 

assist you and others in determining 

whether this action might apply to 

certain entities. If you have any 

questions regarding the applicability of 

this action to a particular entity, consult 

the person listed under FOR FURTHER

INFORMATION CONTACT. 

B. How can I get electronic access to 

other related information? 

You may access a frequently updated 

electronic version of EPA’s tolerance 

regulations at 40 CFR part 180 through 

the Government Printing Office’s e-CFR 

site at http://www.gpoaccess.gov/ecfr. 

To access the harmonized test 

guidelines referenced in this document 

electronically, please go to http:// 

www.epa.gov/ocspp and select ‘‘Test 

Methods and Guidelines.’’ 

C. How can I file an objection or hearing 

request? 

Under FFDCA section 408(g), 21 

U.S.C. 346a, any person may file an 

objection to any aspect of this regulation 

and may also request a hearing on those 

objections. You must file your objection 

or request a hearing on this regulation 

in accordance with the instructions 

provided in 40 CFR part 178. To ensure 

proper receipt by EPA, you must 

identify docket ID number EPA–HQ– 

OPP–2010–0268 in the subject line on 

the first page of your submission. All 

objections and requests for a hearing 

must be in writing, and must be 

received by the Hearing Clerk on or 

before August 1, 2011. Addresses for 

mail and hand delivery of objections 

and hearing requests are provided in 40 

CFR 178.25(b). 

In addition to filing an objection or 

hearing request with the Hearing Clerk 

as described in 40 CFR part 178, please 

submit a copy of the filing that does not 

contain any CBI for inclusion in the 

public docket. Information not marked 

confidential pursuant to 40 CFR part 2 

may be disclosed publicly by EPA 

without prior notice. Submit a copy of 

your non-CBI objection or hearing 

request, identified by docket ID number 

EPA–HQ–OPP–2010–0268, by one of 

the following methods: 

• Federal eRulemaking Portal: http:// 

www.regulations.gov. Follow the on-line 

instructions for submitting comments. 

• Mail: Office of Pesticide Programs 

(OPP) Regulatory Public Docket (7502P), 

Environmental Protection Agency, 1200 

Pennsylvania Ave., NW., Washington, 

DC 20460–0001. 

• Delivery: OPP Regulatory Public 

Docket (7502P), Environmental 

Protection Agency, Rm. S–4400, One 

Potomac Yard (South Bldg.), 2777 S. 

Crystal Dr., Arlington, VA. Deliveries 

are only accepted during the Docket 

Facility’s normal hours of operation 

(8:30 a.m. to 4 p.m., Monday through 

Friday, excluding legal holidays). 

Special arrangements should be made 

for deliveries of boxed information. The 

Docket Facility telephone number is 

(703) 305–5805. 

II. Summary of Petitioned-For 

Tolerance 

In the Federal Register of June 23, 

2010 (75 FR 35801) (FRL–8831–3), EPA 

issued a notice pursuant to section 

408(d)(3) of FFDCA, 21 U.S.C. 

346a(d)(3), announcing the filing of a 

pesticide petition (PP 9F7678) by Bayer 

CropScience LLC, 2 T. W. Alexander 

Drive, Research Triangle Park, NC 

27709. The petition requested that 40 

CFR 180.324 be amended by increasing 

existing tolerances for residues of the 

herbicide bromoxynil, 3,5-dibromo-4- 

hydroxybenzonitrile, in or on sorghum, 

grain, grain from 0.05 parts per million 

(ppm) to 0.2 ppm; grass, hay from 3.0 

ppm to 5.0 ppm; and grass, forage from 

3.0 ppm to 18 ppm. That notice 

referenced a summary of the petition 

prepared by Bayer CropScience LLC, the 

registrant, which is available in the 

docket, http://www.regulations.gov. 

There were no comments received in 

response to the notice of filing. 

Based upon review of the data 

supporting the petition, EPA has 

determined that the existing tolerances 

for aspirated grain fractions, milk, and 

grain sorghum forage must also be 

increased as a result of the proposed 

changes to the use patterns for sorghum 

and grasses. The reasons for these 

changes are explained in Unit IV.C. 


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III. Aggregate Risk Assessment and 

Determination of Safety 

Section 408(b)(2)(A)(i) of FFDCA 

allows EPA to establish a tolerance (the 

legal limit for a pesticide chemical 

residue in or on a food) only if EPA 

determines that the tolerance is ‘‘safe.’’ 

Section 408(b)(2)(A)(ii) of FFDCA 

defines ‘‘safe’’ to mean that ‘‘there is a 

reasonable certainty that no harm will 

result from aggregate exposure to the 

pesticide chemical residue, including 

all anticipated dietary exposures and all 

other exposures for which there is 

reliable information.’’ This includes 

exposure through drinking water and in 

residential settings, but does not include 

occupational exposure. Section 

408(b)(2)(C) of FFDCA requires EPA to 

give special consideration to exposure 

of infants and children to the pesticide 

chemical residue in establishing a 

tolerance and to ‘‘ensure that there is a 

reasonable certainty that no harm will 

result to infants and children from 

aggregate exposure to the pesticide 

chemical residue * * *.’’ 

Consistent with section 408(b)(2)(D) 

of FFDCA, and the factors specified in 

section 408(b)(2)(D) of FFDCA, EPA has 

reviewed the available scientific data 

and other relevant information in 

support of this action. EPA has 

sufficient data to assess the hazards of 

and to make a determination on 

aggregate exposure for bromoxynil 

including exposure resulting from the 

tolerances established by this action. 

EPA’s assessment of exposures and risks 

associated with bromoxynil follows. 

A. Toxicological Profile 

EPA has evaluated the available 

toxicity data and considered its validity, 

completeness, and reliability as well as 

the relationship of the results of the 

studies to human risk. EPA has also 

considered available information 

concerning the variability of the 

sensitivities of major identifiable 

subgroups of consumers, including 

infants and children. 

Bromoxynil phenol has moderate 

acute toxicity via the oral and inhalation 

routes of exposure and low acute 

toxicity via the dermal route. 

Bromoxynil octanoate has moderate 

acute toxicity via the oral and dermal 

routes and low acute toxicity via the 

inhalation route. Due to rapid 

conversion of the ester forms of the 

chemical (heptanoate and octanoate) to 

the phenol, toxicity testing was 

conducted with both phenol and 

octanoate material, but the risk 

assessment is based on exposure to the 

phenol. 

In the repeated dose studies of the 

mammalian toxicology database, the 

liver was the primary target organ of 

bromoxynil toxicity. Across species, 

duration and gender, changes in weight, 

clinical chemistry and pathology 

indicated treatment-related 

perturbations in and adverse effects on 

liver function. Treatment-related effects 

were also observed on body weight and 

body weight gain in rats, mice, dogs, 

and rabbits. Subchronic and chronic 

studies in dogs showed that bromoxynil 

elevated body temperature, manifested 

by increased panting at lower dose 

levels, and hyperthermia and death as 

dose levels increased. 

Developmental toxicity was 

manifested in rats, mice and rabbits via 

the oral and dermal routes by increased 

incidence of supernumerary (13th and/ 

or 14th) ribs at dose levels as low as 5 

milligrams/kilogram/day (mg/kg/day) in 

rats. At higher dose levels, 

malformations such as hydrocephalus, 

enophthalmia, micropththalmia, fused 

ribs, scoliosis, misshapen thoracic 

centrum and incomplete ossification of 

sternebrae were observed in rabbits. In 

reproduction studies, delayed 

development manifested as decreased 

body weight and body weight gain, and 

delayed eye opening. 

Bromoxynil is classified as a ‘‘possible 

human carcinogen’’ based on the 

presence of hepatocellular tumors in 

male and female mice. There is no 

concern for mutagenicity. The method 

of quantification of cancer risk is linear, 

using the cancer slope factor (Q*) of 

0.103 (mg/kg/day)¥1 in human 

equivalents. 

Specific information on the studies 

received and the nature of the adverse 

effects caused by bromoxynil as well as 

the no-observed-adverse-effect-level 

(NOAEL) and the lowest-observedadverse-effect-level (LOAEL) from the 

toxicity studies can be found at http:// 

www.regulations.gov in document 

‘‘Bromoxynil: Human Health Risk 

Assessment for Amended Uses on Grass 

Grown for Seed, Conservation Reserve 

Program Areas, and Grain Sorghum,’’ p. 

50 in docket ID number EPA–HQ–OPP– 

2010–0268. 

B. Toxicological Points of Departure/ 

Levels of Concern 

Once a pesticide’s toxicological 

profile is determined, EPA identifies 

toxicological points of departure (POD) 

and levels of concern (LOC) to use in 

evaluating the risk posed by human 

exposure to the pesticide. For hazards 

that have a threshold below which there 

is no appreciable risk, the toxicological 

POD is used as the basis for derivation 

of reference values for risk assessment. 

PODs are developed based on a careful 

analysis of the doses in each 

toxicological study to determine the 

dose at which the NOAEL and the 

lowest dose at which adverse effects of 

concern are identified (the LOAEL). 

Uncertainty/safety factors are used in 

conjunction with the POD to calculate a 

safe exposure level—generally referred 

to as a population-adjusted dose (PAD) 

(a = acute and c = chronic) or a reference 

dose (RfD)—and a safe margin of 

exposure (MOE). For non-threshold 

risks, the Agency assumes that any 

amount of exposure will lead to some 

degree of risk. Thus, the Agency 

estimates risk in terms of the probability 

of an occurrence of the adverse effect 

expected in a lifetime. For more 

information on the general principles 

EPA uses in risk characterization and a 

complete description of the risk 

assessment process, see http:// 

www.epa.gov/pesticides/factsheets/ 

riskassess.htm. 

A summary of the toxicological 

endpoints for bromoxynil used for 

human risk assessment is shown in the 

following table. 

TABLE—SUMMARY OF TOXICOLOGICAL DOSES AND ENDPOINTS FOR BROMOXYNIL FOR USE IN HUMAN HEALTH RISK

ASSESSMENT

Exposure/scenario Point of departure and 

uncertainty/safety factors RfD, PAD, LOC for risk assessment Study and toxicological effects 

Acute dietary ....................

(Females 13–50 years of 

age).

NOAEL = 4 mg/kg/day ....

UFA = 10x 

UFH = 10x 

FQPA SF = 1x 

Acute RfD = 0.04 mg/kg/day ......................

aPAD = 0.04 mg/kg/day 

Developmental Studies in Rats. 

LOAEL = 5 mg/kg/day based on an increase of supernumerary ribs. The 

NOAEL is derived from a co-critical rat 

developmental study. 


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Federal Register / Vol. 76, No. 105 / Wednesday, June 1, 2011 / Rules and Regulations 31487 

TABLE—SUMMARY OF TOXICOLOGICAL DOSES AND ENDPOINTS FOR BROMOXYNIL FOR USE IN HUMAN HEALTH RISK

ASSESSMENT—Continued 

Exposure/scenario Point of departure and 

uncertainty/safety factors RfD, PAD, LOC for risk assessment Study and toxicological effects 

Acute dietary ....................

(General population including infants and children).

NOAEL = 8 mg/kg/day ....

UFA = 10x 

UFH = 10x 

FQPA SF = 1x 

Acute RfD = 0.08 mg/kg/day ......................

aPAD = 0.08 mg/kg/day 

Subchronic Study in Dogs. 

LOAEL = 12 mg/kg/day based on panting. 

In addition to panting, elevated rectal 

temperatures occurred at 16 mg/kg and 

above, and death occurred at 30 mg/kg 

and above after a single dose on day 1. 

Chronic dietary .................

(All populations) ...............

NOAEL= 1.5 mg/kg/day ..

UFA = 10x 

UFH = 10x 

FQPA SF = 1x 

Chronic RfD = 0.015 mg/kg/day .................

cPAD = 0.015 mg/kg/day 

Chronic (1 year) Study in dogs. 

LOAEL = 7.5 mg/kg/day based on increased incidences of salivation, panting, liquid feces and pale gums; statistically significant decreased body weight 

gain over entire duration of study, but 

particularly during first 8 weeks of study; 

statistically significant decreased 

erythrocytes (RBC), hemoglobin (Hb) 

and packed cell volume (PCV); statistically significant increased urea nitrogen; increased absolute liver weights 

and liver/body weight ratios. 

Cancer (Oral, dermal, inhalation).Bromoxynil phenol has been classified by EPA as a Group C, possible human carcinogen, based on male mouse 

hepatocellular tumors. The Agency has determined that a linear low dose extrapolation model (Q1*) should be applied to the experimental animal tumor data for quantification of human risk. Q1* = 0.103 (mg/kg/day)¥1

UFA = extrapolation from animal to human (interspecies). UFH = potential variation in sensitivity among members of the human population 

(intraspecies). FQPA SF = Food Quality Protection Act Safety Factor. Pad = population adjusted dose (a = acute, c = chronic), LOC = level of 

concern, RfD = Reference dose. 

C. Exposure Assessment 

1. Dietary exposure from food and 

feed uses. In evaluating dietary 

exposure to bromoxynil, EPA 

considered exposure under the 

petitioned-for tolerances as well as all 

existing bromoxynil tolerances in 40 

CFR 180.324. EPA assessed dietary 

exposures from bromoxynil in food as 

follows: 

i. Acute exposure. Quantitative acute 

dietary exposure and risk assessments 

are performed for a food-use pesticide, 

if a toxicological study has indicated the 

possibility of an effect of concern 

occurring as a result of a 1–day or single 

exposure. Such effects were identified 

for bromoxynil. As shown in the table 

in this unit, EPA identified different 

PODs for assessing acute dietary 

exposure for the general population 

(including infants and children) and 

women of childbearing age (13 to 50 

years). 

In estimating acute dietary exposure, 

EPA used food consumption 

information from the U. S. Department 

of Agriculture (USDA) 1994–1996 and 

1998 Nationwide Continuing Surveys of 

Food Intake by Individuals (CSFII). As 

to residues in food, EPA assumed either 

tolerance level or anticipated residues. 

Tolerance levels were assumed for 

cotton, garlic, onion, peppermint, and 

spearmint. For all grains, average field 

trial values were used, since grains are 

considered to be blended commodities. 

Livestock anticipated residues were 

estimated using results from the crop 

field trials in conjunction with animal 

feeding studies. Additionally, maximum 

percent crop treated (PCT) estimates 

were used for all crop commodities. 

Default processing factors were used to 

estimate residues in processed 

commodities. 

ii. Chronic exposure. In conducting 

the chronic dietary exposure assessment 

EPA used the food consumption data 

from the USDA 1994–1996 and 1998 

CSFII. As to residue levels in food, EPA 

used average field trial residues for all 

commodities except spearmint and 

peppermint, for which tolerance values 

were assumed. Livestock anticipated 

residues were estimated using average 

percent crop treated data, average field 

trial residue values, and results from the 

animal feeding studies. Additionally, 

average PCT estimates were used for all 

crop commodities. Default processing 

factors were used to estimate residues in 

processed commodities. 

iii. Cancer. EPA determines whether 

quantitative cancer exposure and risk 

assessments are appropriate for a fooduse pesticide based on the weight-ofthe-evidence from cancer studies and 

other relevant data. If quantitative 

cancer risk assessment is appropriate, 

cancer risk may be quantified using a 

linear or nonlinear approach. If 

sufficient information on the 

carcinogenic mode of action is available, 

a threshold or non-linear approach is 

used and a cancer RfD is calculated 

based on an earlier noncancer key event. 

If carcinogenic mode of action data are 

not available, or if the mode of action 

data determines a mutagenic mode of 

action, a default linear cancer slope 

factor approach is utilized. Based on the 

data summarized in Unit III.A., EPA has 

concluded that bromoxynil should be 

classified as a ‘‘Possible Human 

Carcinogen,’’ and a linear approach has 

been used to quantify cancer risk. 

Cancer risk was quantified using the 

same exposure estimates as discussed in 

Unit III.C.1.ii.—chronic exposure. 

iv. Anticipated residue and percent 

crop treated (PCT) information. Section 

408(b)(2)(E) of FFDCA authorizes EPA 

to use available data and information on 

the anticipated residue levels of 

pesticide residues in food and the actual 

levels of pesticide residues that have 

been measured in food. If EPA relies on 

such information, EPA must require 

pursuant to FFDCA section 408(f)(1) 

that data be provided 5 years after the 

tolerance is established, modified, or 

left in effect, demonstrating that the 

levels in food are not above the levels 

anticipated. For the present action, EPA 

will issue such data call-ins as are 

required by FFDCA section 408(b)(2)(E) 

and authorized under FFDCA section 

408(f)(1). Data will be required to be 

submitted no later than 5 years from the 

date of issuance of these tolerances. 


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Section 408(b)(2)(F) of FFDCA states 

that the Agency may use data on the 

actual percent of food treated for 

assessing chronic dietary risk only if: 

• Condition a: The data used are 

reliable and provide a valid basis to 

show what percentage of the food 

derived from such crop is likely to 

contain the pesticide residue. 

• Condition b: The exposure estimate 

does not underestimate exposure for any 

significant subpopulation group. 

• Condition c: Data are available on 

pesticide use and food consumption in 

a particular area, the exposure estimate 

does not understate exposure for the 

population in such area. 

In addition, the Agency must provide 

for periodic evaluation of any estimates 

used. To provide for the periodic 

evaluation of the estimate of PCT as 

required by FFDCA section 408(b)(2)(F), 

EPA may require registrants to submit 

data on PCT. 

The Agency estimated the maximum 

PCT for existing uses in the acute 

dietary exposure assessment as follows: 

Alfalfa 2.5%; barley 35%; corn 5%; 

cotton 5%; flax 35%; garlic 70%; mint 

25%; oats 5%; onion 70%; rye 1%; 

sorghum 2.5%; and wheat 35%. 

The Agency estimated the average 

PCT for existing uses in the chronic and 

cancer dietary exposure assessments as 

follows: Alfalfa 1%; barley 20%; corn 

2.5%; cotton 2.5%; flax 35%; garlic 

50%; mint 25%; oats 5%; onion 55%; 

rye 1%; sorghum 2.5%; and wheat 15%. 

The sorghum PCT values used in the 

acute and chronic assessments were 

based on existing uses. Because there is 

a proposed change in the sorghum use 

pattern (i.e., shorter pre-harvest 

interval), there is a potential for a 

change in the PCT value. However, 

grain sorghum is a small contributor to 

the overall livestock dietary burden 

estimate. If the PCT value for sorghum 

was assumed to be 100%, the overall 

impact to dietary exposure and risk 

assessment would be negligible. 

In most cases, EPA uses available data 

from U. S. Department of Agriculture/ 

National Agricultural Statistics Service 

(USDA/NASS), proprietary market 

surveys, and the National Pesticide Use 

Database for the chemical/crop 

combination for the most recent 6–7 

years. EPA uses an average PCT for 

chronic dietary risk analysis. The 

average PCT figure for each existing use 

is derived by combining available 

public and private market survey data 

for that use, averaging across all 

observations, and rounding to the 

nearest 5%, except for those situations 

in which the average PCT is less than 

one. In those cases, 1% is used as the 

average PCT and 2.5% is used as the 

maximum PCT. EPA uses a maximum 

PCT for acute dietary risk analysis. The 

maximum PCT figure is the highest 

observed maximum value reported 

within the recent 6 years of available 

public and private market survey data 

for the existing use and rounded up to 

the nearest multiple of 5%. 

The Agency believes that the three 

conditions discussed in Unit III.C.1.iv. 

have been met. With respect to 

Condition a, PCT estimates are derived 

from Federal and private market survey 

data, which are reliable and have a valid 

basis. The Agency is reasonably certain 

that the percentage of the food treated 

is not likely to be an underestimation. 

As to Conditions b and c, regional 

consumption information and 

consumption information for significant 

subpopulations are taken into account 

through EPA’s computer-based model 

for evaluating the exposure of 

significant subpopulations including 

several regional groups. Use of this 

consumption information in EPA’s risk 

assessment process ensures that EPA’s 

exposure estimate does not understate 

exposure for any significant 

subpopulation group and allows the 

Agency to be reasonably certain that no 

regional population is exposed to 

residue levels higher than those 

estimated by the Agency. Other than the 

data available through national food 

consumption surveys, EPA does not 

have available reliable information on 

the regional consumption of food to 

which bromoxynil may be applied in a 

particular area. 

2. Dietary exposure from drinking 

water. The Agency used screening level 

water exposure models in the dietary 

exposure analysis and risk assessment 

for bromoxynil in drinking water. These 

simulation models take into account 

data on the physical, chemical, and fate/ 

transport characteristics of bromoxynil. 

Further information regarding EPA 

drinking water models used in pesticide 

exposure assessment can be found at 

http://www.epa.gov/oppefed1/models/ 

water/index.htm. 

Based on the FQPA Index Reservoir 

Screening Tool (FIRST) and Screening 

Concentration in Ground Water (SCI– 

GROW) models, the estimated drinking 

water concentrations (EDWCs) of 

bromoxynil for acute exposures are 

estimated to be 11.5 parts per billion 

(ppb) for surface water and 3.26 parts 

per trillion (ppt) for ground water. 

EDWCs for chronic exposures for noncancer assessments and cancer 

assessments are estimated to be 0.19 

ppb for surface water and 3.26 ppt for 

ground water. 

Modeled estimates of drinking water 

concentrations were directly entered 

into the dietary exposure model. For 

acute dietary risk assessment, the water 

concentration value of 11.5 ppb was 

used to assess the contribution to 

drinking water. For chronic and cancer 

dietary risk assessment, the water 

concentration value of 0.19 ppb was 

used to assess the contribution to 

drinking water. 

3. From non-dietary exposure. The 

term ‘‘residential exposure’’ is used in 

this document to refer to nonoccupational, non-dietary exposure 

(e.g., for lawn and garden pest control, 

indoor pest control, termiticides, and 

flea and tick control on pets). 

Bromoxynil is not registered for any 

specific use patterns that would result 

in residential exposure. 

4. Cumulative effects from substances 

with a common mechanism of toxicity. 

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 found bromoxynil to 

share a common mechanism of toxicity 

with any other substances, and 

bromoxynil does not appear to produce 

a toxic metabolite produced by other 

substances. For the purposes of this 

tolerance action, therefore, EPA has 

assumed that bromoxynil 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 EPA’s Web site at http:// 

www.epa.gov/pesticides/cumulative. 

D. Safety Factor for Infants and 

Children 

1. In general. Section 408(b)(2)(C) of 

FFDCA provides that EPA shall apply 

an additional tenfold (10X) margin of 

safety for infants and children in the 

case of threshold effects to account for 

prenatal and postnatal toxicity and the 

completeness of the database on toxicity 

and exposure unless EPA determines 

based on reliable data that a different 

margin of safety will be safe for infants 

and children. This additional margin of 

safety is commonly referred to as the 

FQPA SF. In applying this provision, 

EPA either retains the default value of 

10X, or uses a different additional safety 

factor when reliable data available to 

EPA support the choice of a different 

factor. 


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2. Prenatal and postnatal sensitivity. 

The prenatal and postnatal toxicity 

database for bromoxynil includes five 

developmental toxicity studies in rats, 

two developmental toxicity studies in 

rabbits, a developmental study in mice, 

and 2- and 3-generation reproduction 

toxicity studies in rats. The available 

data indicate that bromoxynil produces 

developmental effects (supernumerary 

ribs) in rats and rabbits at or below the 

maternal NOAELs in both oral and 

dermal studies, and that bromoxynil 

octanoate produces supernumerary ribs 

at the maternal NOAEL in a dermal 

study. Supernumerary ribs were 

observed in rats, mice and rabbits after 

oral and/or dermal administration. 

Therefore, there is evidence of 

quantitative susceptibility in the 

database. However, clear NOAELs exist 

for the developmental effects, and 

basing the point of departure on these 

effects addresses Agency concerns for 

quantitative susceptibility. 

In EPA’s previous risk assessment for 

bromoxynil (1998), the FQPA SF was 

retained at 10X for the acute dietary 

endpoint for females, 13 to 50 years old, 

despite the POD being an adverse effect 

(supernumerary ribs) in the fetus. The 

primary reason for the retention was an 

apparent steepness of the dose-response 

curve (NOAEL = 4 mg/kg/day, LOAEL = 

5 mg/kg/day) derived by combining the 

results of two co-critical studies. 

However, since the previous risk 

assessment for bromoxynil was 

conducted, a more refined data 

evaluation tool, benchmark dose (BMD) 

analysis, has become available and EPA 

has used it in this risk assessment to 

better characterize the dose-response 

relationship for supernumerary ribs. 

The analysis was conducted using the 

fetal and/or litter data available from the 

two rat developmental studies, plus a 

third developmental study which 

demonstrated similar results at similar 

dose levels. EPA also re-examined the 

underlying data for each study. EPA 

concluded that it was no longer 

appropriate to combine the rat 

developmental study with a NOAEL of 

4 mg/kg/day with other studies in 

characterizing the dose-response 

relationship and that none of the studies 

indicate a steep dose-response curve. 

EPA further found that the results of the 

BMD analysis as to the study used to 

derive the POD (the rat developmental 

study with a NOAEL of 4 mg/kg/day) 

suggest a POD substantially higher than 

the NOAEL of 4 mg/kg/day, which 

supports the position that the NOAEL of 

4 mg/kg/day is adequately protective of 

the adverse effect of supernumerary ribs 

in rat fetuses without an additional 

safety factor. Accordingly, EPA has 

determined, after re-examining all three 

studies, that the data on developmental 

effects do not raise any residual 

concerns. 

3. Conclusion. EPA has determined 

that reliable data show the safety of 

infants and children would be 

adequately protected if the FQPA SF 

were reduced to 1X. That decision is 

based on the following findings: 

i. The toxicity database for 

bromoxynil is complete, except for an 

immunotoxicity study (OPPTS 

Guideline 870.7800), and acute and 

subchronic neurotoxicity studies 

(OPPTS Guideline 870.6200a and 

870.6200b), now required under 40 CFR 

158.500 for pesticide registration. In the 

absence of specific immunotoxicity and 

acute and subchronic neurotoxicity 

studies, EPA has evaluated the available 

bromoxynil toxicity database to 

determine whether an additional 

database UF is needed to account for 

potential immunotoxicity or 

neurotoxicity. 

With the exception of a marginal 

increase in the severity, but not the 

incidence, of thymic lymphocyte 

necrosis at otherwise toxic dose levels 

in a subchronic rat study, there is no 

evidence of immunotoxicity in the 

toxicology database for bromoxynil. 

Similarly, there is no evidence of 

neurotoxicity in the database. 

Consequently, EPA believes the existing 

data are sufficient for endpoint selection 

for exposure/risk assessment scenarios 

and for evaluation of the requirements 

under FQPA, and an additional database 

UF is not needed to account for the lack 

of these studies. 

ii. Although there is evidence that 

bromoxynil results in increased 

quantitative susceptibility in in utero 

rats and rabbits in the prenatal 

developmental studies, EPA did not 

identify any residual uncertainties after 

establishing toxicity endpoints and 

traditional UFs to be used in the risk 

assessment of bromoxynil. 

iii. There are no residual uncertainties 

identified in the exposure databases. 

Although the dietary assessments were 

refined, they were based on reliable and 

acceptable field trial and feeding studies 

and valid estimates of PCT. EPA made 

conservative (protective) assumptions in 

the ground water and surface water 

modeling used to assess exposure to 

bromoxynil in drinking water. These 

assessments will not under estimate the 

exposure and risks posed by 

bromoxynil. 

E. Aggregate Risks and Determination of 

Safety 

EPA determines whether acute and 

chronic dietary pesticide exposures are 

safe by comparing aggregate exposure 

estimates to the aPAD and cPAD. For 

linear cancer risks, EPA calculates the 

lifetime probability of acquiring cancer 

given the estimated aggregate exposure. 

Short-, intermediate-, and chronic-term 

risks are evaluated by comparing the 

estimated aggregate food, water, and 

residential exposure to the appropriate 

PODs to ensure that an adequate MOE 

exists. 

1. Acute risk. Using the exposure 

assumptions discussed in this unit for 

acute exposure, the acute dietary 

exposure to bromoxynil from food and 

water will occupy 7.4% of the aPAD for 

infants less than 1 year old, the 

population group receiving the greatest 

exposure. The acute dietary exposure to 

bromoxynil from food and water will 

occupy 4.4% of the aPAD for females 13 

to 50 years old. 

2. Chronic risk. Using the exposure 

assumptions described in this unit for 

chronic exposure, EPA has concluded 

that chronic exposure to bromoxynil 

from food and water will utilize <1% of 

the cPAD for all population groups, 

including infants and children. There 

are no residential uses for bromoxynil. 

3. Short- and intermediate-term risk. 

Short- and intermediate-term aggregate 

exposure take into account short- or 

intermediate-term residential exposure 

plus chronic exposure from food and 

water (considered to be a background 

exposure level). Short- and 

intermediate-term adverse effects were 

identified; however, bromoxynil is not 

registered for any use patterns that 

would result in short- or intermediateterm residential exposure. Short- and 

intermediate-term risks are assessed 

based on short- or intermediate-term 

residential exposure plus chronic 

dietary exposure. Because there is no 

short- or intermediate-term residential 

exposure and chronic dietary exposure 

has already been assessed under the 

appropriately protective cPAD (which is 

at least as protective as the POD used to 

assess short- and intermediate-term 

risk), no further assessment of short- or 

intermediate-term risk is necessary, and 

EPA relies on the chronic dietary risk 

assessment for evaluating short- and 

intermediate-term risk for bromoxynil. 

4. Aggregate cancer risk for U.S. 

population. Using the exposure 

assumptions described in this unit for 

the cancer risk assessment, EPA has 

concluded that exposure to bromoxynil 

from food and water will result in a 

lifetime cancer risk of 1.5 × 10¥6 for the 


jlentini on DSK4TPTVN1PROD with RULES
31490 Federal Register / Vol. 76, No. 105 / Wednesday, June 1, 2011 / Rules and Regulations 

general U.S. population. EPA generally 

considers cancer risks in the range of 

one in one million (1 × 10¥6) or less to 

be negligible. The precision which can 

be assumed for cancer risk estimates is 

best described by rounding to the 

nearest integral order of magnitude on 

the log scale; for example, risks falling 

between 3 × 10¥7 and 3 × 10¥6 are 

expressed as risks in the range of 10¥6. 

Considering the precision with which 

cancer hazard can be estimated, the 

conservativeness of low-dose linear 

extrapolation, and the rounding 

procedure described above, cancer risk 

should generally not be assumed to 

exceed the benchmark level of concern 

of the range of 10¥6 until the calculated 

risk exceeds approximately 3 × 10¥6. 

This is particularly the case where some 

conservatism is maintained in the 

exposure assessment. Although the 

bromoxynil exposure risk assessment is 

refined, it retains some conservatism 

due, among other things, to the use of 

field trial data and screening level PCT 

information to estimate residues in food. 

Accordingly, EPA has concluded the 

cancer risk for all existing bromoxynil 

uses and the uses associated with the 

tolerances established in this action falls 

within the range of 1 × 10¥6 and is thus 

negligible. 

5. Determination of safety. Based on 

these risk assessments, EPA concludes 

that there is a reasonable certainty that 

no harm will result to the general 

population, or to infants and children 

from aggregate exposure to bromoxynil 

residues. 

IV. Other Considerations 

A. Analytical Enforcement Methodology 

Adequate enforcement methodology 

is available to enforce the tolerance 

expression for residues of bromoxynil in 

grass and grain sorghum commodities. 

Method I in the Pesticide Analytical 

Manual (PAM), Vol. II, is a gas liquid 

chromatography/microcoulometric 

detection (GLC/MCD) method that has 

undergone a successful EPA method 

validation on wheat grain. Method Ia is 

the same method except that it uses gas 

chromatography/electron capture 

detection (GC/ECD) for determination of 

methylated bromoxynil. 

Adequate residue analytical 

methodology is available for tolerance 

enforcement for bromoxynil in livestock 

commodities. Method A is a GC/MCD or 

GC/ECD method for the analysis of 

bromoxynil residues in livestock tissues 

and is essentially the same as Method I. 

Method B is a GC/ECD method that is 

also similar to Method I, with 

modifications to the cleanup 

procedures. The methods may be 

requested from: Chief, Analytical 

Chemistry Branch, Environmental 

Science Center, 701 Mapes Rd., Ft. 

Meade, MD 20755–5350; telephone 

number: (410) 305–2905; e-mail address: 

residuemethods@epa.gov. 

B. International Residue Limits 

In making its tolerance decisions, EPA 

seeks to harmonize U.S. tolerances with 

international standards whenever 

possible, consistent with U.S. food 

safety standards and agricultural 

practices. EPA considers the 

international maximum residue limits 

(MRLs) established by the Codex 

Alimentarius Commission (Codex), as 

required by FFDCA section 408(b)(4). 

The Codex Alimentarius is a joint U.N. 

Food and Agriculture Organization/ 

World Health Organization food 

standards program, and it is recognized 

as an international food safety 

standards-setting organization in trade 

agreements to which the United States 

is a party. EPA may establish a tolerance 

that is different from a Codex MRL; 

however, FFDCA section 408(b)(4) 

requires that EPA explain the reasons 

for departing from the Codex level. 

The Codex has not established a MRL 

for bromoxynil on the commodities in 

this rule. 

C. Revisions to Petitioned-For 

Tolerances 

The proposed increases in the 

tolerance levels for ‘‘grass, forage;’’ 

‘‘grass, hay;’’ and ‘‘sorghum, grain’’ were 

determined to be appropriate for these 

commodities. However, EPA 

determined that the existing tolerance 

for ‘‘sorghum, grain, forage’’ must also be 

increased from 0.5 ppm to 0.8 ppm, 

based on analysis of the field trial data 

using the Agency’s tolerance/MRL 

calculator in accordance with the 

Agency’s Guidance for Setting Pesticide 

Tolerances Based on Field Trial Data. In 

addition, because the tolerance on the 

grain of grain sorghum is being 

increased from 0.05 ppm to 0.2 ppm, 

higher residues may occur in aspirated 

grain fractions; and EPA has determined 

that the existing tolerance should be 

increased from 0.3 ppm to 1.2 ppm. 

Finally, based on calculated livestock 

dietary burdens in light of the new 

tolerances and data from a cattle feeding 

study, EPA has determined that the 

established tolerance for milk must be 

increased from 0.1 ppm to 0.4 ppm. 

EPA is also revising the tolerance 

expression for existing tolerances and 

the new tolerances to clarify the 

chemical moieties that are covered by 

the tolerances and specify how 

compliance with the tolerances is to be 

determined. Tolerances for most plant 

commodities are currently expressed in 

terms of ‘‘bromoxynil (3,5-dibromo-4- 

hydroxybenzonitrile) resulting from 

application of its octanoic and/or 

heptanoic acid ester.’’ Livestock 

tolerances and tolerances for cotton 

commodities are currently expressed in 

terms of ‘‘bromoxynil (3,5-dibromo-4- 

hydroxybenzonitrile) and its metabolite 

3,5-dibromo-4-hydroxybenzoic acid 

(DBHA) resulting from application of its 

octanoic and/or heptanoic acid ester.’’ 

The tolerance expression for plants, 

except cotton, is being revised to make 

clear that the tolerances cover residues 

of bromoxynil, including its metabolites 

and degradates, but that compliance 

with the tolerances is to be determined 

by measuring only bromoxynil. 

Similarly, the tolerance expression for 

livestock commodities and cotton is 

being revised to clarify that the 

tolerances cover residues of bromoxynil, 

including its metabolites and 

degradates, but that compliance with 

the tolerance levels will be determined 

by measuring only bromoxynil and its 

metabolite DBHA. EPA has determined 

that it is reasonable to make these 

changes final without prior proposal 

and opportunity for comment, because 

public comment is not necessary, in that 

the changes have no substantive effect 

on the tolerances, but rather are merely 

intended to clarify the existing tolerance 

expressions. 

V. Conclusion 

Therefore, previously established 

tolerances are amended for residues of 

bromoxynil, including its metabolites 

and degradates, as set forth in the 

regulatory text. 

VI. Statutory and Executive Order 

Reviews 

This final rule establishes tolerances 

under section 408(d) of FFDCA in 

response to a petition submitted to the 

Agency. The Office of Management and 

Budget (OMB) has exempted these types 

of actions from review under Executive 

Order 12866, entitled Regulatory 

Planning and Review (58 FR 51735, 

October 4, 1993). Because this final rule 

has been exempted from review under 

Executive Order 12866, this final rule is 

not subject to Executive Order 13211, 

entitled Actions Concerning Regulations 

That Significantly Affect Energy Supply, 

Distribution, or Use (66 FR 28355, May 

22, 2001) or Executive Order 13045, 

entitled Protection of Children from 

Environmental Health Risks and Safety 

Risks (62 FR 19885, April 23, 1997). 

This final rule does not contain any 

information collections subject to OMB 

approval under the Paperwork 

Reduction Act, 44 U.S.C. 3501 et seq., 


jlentini on DSK4TPTVN1PROD with RULES
Federal Register / Vol. 76, No. 105 / Wednesday, June 1, 2011 / Rules and Regulations 31491 

nor does it require any special 

considerations under Executive Order 

12898, entitled Federal Actions to 

Address Environmental Justice in 

Minority Populations and Low-Income 

Populations (59 FR 7629, February 16, 

1994). 

Since tolerances and exemptions that 

are established on the basis of a petition 

under section 408(d) of FFDCA, such as 

the tolerances in this final rule, do not 

require the issuance of a proposed rule, 

the requirements of the Regulatory 

Flexibility Act (5 U.S.C. 601 et seq.) do 

not apply. 

This final rule directly regulates 

growers, food processors, food handlers, 

and food retailers, not States or tribes, 

nor does this action alter the 

relationships or distribution of power 

and responsibilities established by 

Congress in the preemption provisions 

of section 408(n)(4) of FFDCA. As such, 

the Agency has determined that this 

action will not have a substantial direct 

effect on States or tribal governments, 

on the relationship between the national 

government and the States or tribal 

governments, or on the distribution of 

power and responsibilities among the 

various levels of government or between 

the Federal Government and Indian 

tribes. Thus, the Agency has determined 

that Executive Order 13132, entitled 

Federalism (64 FR 43255, August 10, 

1999) and Executive Order 13175, 

entitled Consultation and Coordination 

with Indian Tribal Governments (65 FR 

67249, November 9, 2000) do not apply 

to this final rule. In addition, this final 

rule does not impose any enforceable 

duty or contain any unfunded mandate 

as described under Title II of the 

Unfunded Mandates Reform Act of 1995 

(Pub. L. 104–4). 

This action does not involve any 

technical standards that would require 

Agency consideration of voluntary 

consensus standards pursuant to section 

12(d) of the National Technology 

Transfer and Advancement Act of 1995, 

Public Law 104–113, section 12(d) (15 

U.S.C. 272 note). 

VII. Congressional Review Act 

The Congressional Review Act, 5 

U.S.C. 801 et seq., generally provides 

that before a rule may take effect, the 

agency promulgating the rule must 

submit a rule report to each House of 

the Congress and to the Comptroller 

General of the United States. EPA will 

submit a report containing this rule and 

other required information to the U.S. 

Senate, the U.S. House of 

Representatives, and the Comptroller 

General of the United States prior to 

publication of this final rule in the 

Federal Register. This final rule is not 

a ‘‘major rule’’ as defined by 5 U.S.C. 

804(2). 

List of Subjects in 40 CFR Part 180 

Environmental protection, 

Administrative practice and procedure, 

Agricultural commodities, Pesticides 

and pests, Reporting and recordkeeping 

requirements. 

Dated: May 18, 2011. 

Lois Rossi, 

Director, Registration Division, Office of 

Pesticide Programs. 

Therefore, 40 CFR chapter I is amended as 

follows: 

PART 180—[AMENDED] 

■ 1. The authority citation for part 180 

continues to read as follows: 

Authority: 21 U.S.C. 321(q), 346a and 371. 

■ 2. Section 180.324 is amended as 

follows: 

■ i. Revise the introductory text in 

paragraph (a)(1), and the entries for 

grain, aspirated fractions; grass, forage; 

grass, hay; sorghum, grain, forage; and 

sorghum, grain, grain in the table to 

paragraph (a)(1). 

■ ii. Revise the introductory text in 

paragraph (a)(2), and the entry for 

‘‘milk’’ in the table to paragraph (a)(2). 

The revisions read as follows: 

§ 180.324 Bromoxynil; tolerances for 

residues. 

(a) General. (1) Tolerances are 

established for residues of the herbicide 

bromoxynil, including its metabolites 

and degradates, in or on the 

commodities in the table below. 

Compliance with the tolerance levels is 

to be determined by measuring only 

bromoxynil, 3,5-dibromo-4- 

hydroxybenzonitrile, resulting from 

application of its octanoic and/or 

heptanoic acid ester, in or on the 

commodities. 

Commodity Parts per 

million 

* * * * * 

Grain, aspirated fractions ......... 1 .2 

Grass, forage ............................ 18 

Grass, hay ................................ 5 .0 

* * * * * 

Sorghum, grain, forage ............. 0 .8 

Sorghum, grain, grain ............... 0 .2 

* * * * * 

(2) Tolerances are established for 

residues of the herbicide bromoxynil, 

3,5-dibromo-4-hydroxybenzonitrile, 

including its metabolites and 

degradates, in or on the commodities in 

the table below. Compliance with the 

tolerance levels is to be determined by 

measuring only bromoxynil and its 

metabolite, 3,5-dibromo-4- 

hydroxybenzoic acid (DBHA), resulting 

from application of its octanoic and/or 

heptanoic acid ester, in or on the 

commodities. 

Commodity Parts per 

million 

* * * * * 

Milk ........................................... 0.4 

* * * * * 

* * * * * 

[FR Doc. 2011–13565 Filed 5–31–11; 8:45 am] 

BILLING CODE 6560–50–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

50 CFR Part 648 

[Docket No. 110502274–1275–01] 

RIN 0648–BB05 

Fisheries of the Northeastern United 

States; Atlantic Sea Scallop Fishery; 

Closure of the Nantucket Lightship 

Access Area 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Temporary rule; emergency 

action. 

SUMMARY: NMFS issues this temporary 

rule pursuant to its authority to 

implement emergency measures under 

the Magnuson-Stevens Fishery 

Conservation and Management Act 

(Magnuson-Stevens Act). This 

emergency rule closes the Nantucket 

Lightship Access Area (NLS) prior to its 

scheduled opening on June 15, 2011, 

and is consistent with Framework 

Adjustment 22 to the Atlantic Sea 

Scallop Fishery Management Plan 

(FMP) (Framework 22), which is 

currently being proposed and subject to 

public comments, and which would 

close the NLS in FY 2011 as well. This 

closure prevents potentially high levels 

of scallop and yellowtail flounder 

(yellowtail) catch that could result from 

opening the area prior to the approval 

and implementation of Framework 22, 

which could be detrimental to the longterm management and health of the 

scallop fishery. 


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