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bromoxynil (Brominal, Buctril) Pesticide Tolerance 5/98

 

[Federal Register: May 13, 1998 (Volume 63, Number 92)]
[Rules and Regulations]               
[Page 26473-26481]
>From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr13my98-38]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300661; FRL-5790-8]
RIN 2070-AB78

 
Bromoxynil; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes tolerances for bromoxynil and DBHA 
in or on cotton. In addition, this regulation establishes tolerances 
for bromoxynil and DBHA in or on meat, meat by products, and fat of 
cattle, hogs, horses, goats, and sheep. Further, this regulation 
establishes tolerances for bromoxynil and DBHA in milk, eggs, and 
poultry meat, meat by-products, and fat. Rhone-Poulenc Ag Company 
requested the tolerances for cotton under the Federal Food, Drug, and 
Cosmetic Act, as amended by the Food Quality Protection Act of 1996 
(Pub. L. 104-170).

DATES: This regulation is effective May 13, 1998. Objections and 
requests for hearings must be received by EPA on or before July 13, 
1998.

ADDRESSES: Written objections and hearing requests, identified by the 
docket control number, [OPP-300661], must be submitted to: Hearing 
Clerk (1900), Environmental Protection Agency, Rm. M3708, 401 M St., 
SW., Washington, DC 20460. Fees accompanying objections and hearing 
requests shall be labeled ``Tolerance Petition Fees'' and forwarded to: 
EPA Headquarters Accounting Operations Branch, OPP (Tolerance Fees), 
P.O. Box 360277M, Pittsburgh, PA 15251. A copy of any objections and 
hearing requests filed with the Hearing Clerk identified by the docket 
control number, [OPP-300661], must also be submitted to: Public 
Information and Records Integrity Branch, Information Resources and 
Services Division (7502C), Office of Pesticide Programs, Environmental 
Protection Agency, 401 M St., SW., Washington, DC 20460. In person, 
bring a copy of objections and hearing requests to Rm. 119, CM #2, 1921 
Jefferson Davis Hwy., Arlington, VA.
    A copy of objections and hearing requests filed with the Hearing 
Clerk may also be submitted electronically by sending electronic mail 
(e-mail) to: opp-docket@epamail.epa.gov. Copies of objections and 
hearing requests must be submitted as an ASCII file avoiding the use of 
special characters and any form of encryption. Copies of objections and 
hearing requests will also be accepted on disks in WordPerfect 5.1/6.1 
file format or ASCII file format. All copies of objections and hearing 
requests in electronic form must be identified by the docket control 
number [OPP-300661]. No Confidential Business Information (CBI) should 
be submitted through e-mail. Electronic copies of objections and 
hearing requests on this rule may be filed online at many Federal 
Depository Libraries.

FOR FURTHER INFORMATION CONTACT: By mail: Jim Tompkins, Registration 
Division (7505C), Office of Pesticide Programs, Environmental 
Protection Agency, 401 M St., SW., Washington, DC 20460. Office 
location, telephone number, and e-mail address: Crystal Mall #2, 1921 
Jefferson Davis Hwy., Arlington, VA, 703-305-5697, e-mail: 
tompkins.jim@epamail.epa.gov.

SUPPLEMENTARY INFORMATION: In the Federal Register of November 26, 1997 
(62 FR 63170) (FRL-5755-6), EPA, issued a notice pursuant to section 
408 of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 
346a(e) announcing the filing of a pesticide petition (PP) 3F4233 for 
tolerance by Rhone-Poulenc Ag Company. This notice included a summary 
of the petition prepared by Rhone-Poulenc Ag Company, the registrant. 
Comments in response to the notice of filing were received from public 
interest groups, individual concerned citizens, agricultural extension 
agents, representatives of State agencies, individual growers, and 
industry groups. The issues raised were the same issues raised in 
response to the proposed rule (May 2, 1997, 62 FR 24065) (FRL-5617-5) 
for the bromoxynil tolerance that expired on January 1, 1998. Many of 
the comments are addressed in this document. Responses to other 
significant comments are presented in Unit III. of the final rule for 
last year's tolerance (June 18, 1997, 62 FR 33019) (FRL-5724-9) or in a 
Response to Comments document that has been included in the docket for 
that action.
    The petition requested that 40 CFR 180.324 be amended by 
establishing tolerances for residues of the herbicide bromoxynil plus 
its metabolite DBHA (3,5-dibromo-4-hydroxybenzoic acid) resulting from 
the application of octanoic and heptanoic acid esters of bromoxynil to 
cotton: undelinted cottonseed at 7 parts per million (ppm), cotton gin 
byproducts at 50 ppm, and cotton hulls at 21 ppm. (Active ingredient 
codes are 35302 for the octanoic acid ester, and 128920 for the 
heptanoic acid ester. CAS Reg. Nos. are

[[Page 26474]]

1689-99-2 for the octanoic acid ester, and 56634-95-8 for the heptanoic 
acid ester.) The tolerances established in this final rule differ from 
these tolerances proposed by the registrant as the result of the review 
of residue data for bromoxynil and DBHA in cotton commodities submitted 
by the registrant after the petition was filed. In addition, the 
petition requested that the maximum allowable cotton acreage that can 
be treated annually with bromoxynil be increased from 400,000 acres to 
1.3 million acres.
    In the Federal Register of May 24, 1995 (60 FR 27414) (FRL-4953-9), 
EPA established a time-limited tolerance under section 408 of the 
FFDCA, 21 U.S.C. 346a, for residues of the herbicide bromoxynil, (3,5-
dibromo-4- hydroxybenzonitrile) on cottonseed. This tolerance expired 
on April 1, 1997. The tolerance was established in response to a 
petition filed by the Rhone-Poulenc AG Company, P.O. Box 12014, 2 T.W. 
Alexander Drive, Research Triangle Park, NC 27709.
    In the Federal Register of May 2, 1997 (62 FR 24065), EPA issued a 
proposed rule for establishment of tolerances on cotton commodities and 
poultry, eggs, and milk, and revision of tolerances on other livestock. 
In the Federal Register of June 18, 1997 (62 FR 33019), EPA issued a 
final rule for establishment of tolerances on cotton commodities and 
poultry, eggs, and milk, and revision of tolerances on other livestock. 
The tolerances for the cotton commodities expired on January 1, 1998.

I. Risk Assessment and Statutory Findings

    New section 408(b)(2)(A)(i) of the 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) 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) 
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. . . .''
    EPA performs a number of analyses to determine the risks from 
aggregate exposure to pesticide residues. First, EPA determines the 
toxicity of pesticides based primarily on toxicological studies using 
laboratory animals. These studies address many adverse health effects, 
including (but not limited to) reproductive effects, developmental 
toxicity, toxicity to the nervous system, and carcinogenicity. Second, 
EPA examines exposure to the pesticide through the diet (e.g., food and 
drinking water) and through exposures that occur as a result of 
pesticide use in residential settings.

A. Toxicity

    1. Threshold and non-threshold effects. For many animal studies, a 
dose response relationship can be determined, which provides a dose 
that causes adverse effects (threshold effects) and doses causing no 
observed effects (the ``no-observed effect level'' or ``NOEL'').
    Once a study has been evaluated and the observed effects have been 
determined to be threshold effects, EPA generally divides the NOEL from 
the study with the lowest NOEL by an uncertainty factor (usually 100 or 
more) to determine the Reference Dose (RfD). The RfD is a level at or 
below which daily aggregate exposure over a lifetime will not pose 
appreciable risks to human health. An uncertainty factor (sometimes 
called a ``safety factor'') of 100 is commonly used since it is assumed 
that people may be up to 10 times more sensitive to pesticides than the 
test animals, and that one person or subgroup of the population (such 
as infants and children) could be up to 10 times more sensitive to a 
pesticide than another. In addition, EPA assesses the potential risks 
to infants and children based on the weight of the evidence of the 
toxicology studies and determines whether an additional uncertainty 
factor is warranted. Thus, an aggregate daily exposure to a pesticide 
residue at or below the RfD (expressed as 100% or less of the RfD) is 
generally considered acceptable by EPA. EPA generally uses the RfD to 
evaluate the chronic risks posed by pesticide exposure. For shorter 
term risks, EPA calculates a margin of exposure (MOE) by dividing the 
estimated human exposure into the NOEL from the appropriate animal 
study. Commonly, EPA finds MOEs lower than 100 to be unacceptable. This 
100-fold MOE is based on the same rationale as the 100-fold uncertainty 
factor.
    Lifetime feeding studies in two species of laboratory animals are 
conducted to screen pesticides for cancer effects. When evidence of 
increased cancer is noted in these studies, the Agency conducts a 
weight of the evidence review of all relevant toxicological data 
including short-term and mutagenicity studies and structure activity 
relationship. Once a pesticide has been classified as a potential human 
carcinogen, different types of risk assessments (e.g., linear low dose 
extrapolations or MOE calculation based on the appropriate NOEL) will 
be carried out based on the nature of the carcinogenic response and the 
Agency's knowledge of its mode of action.
    2. Differences in toxic effect due to exposure duration. The 
toxicological effects of a pesticide can vary with different exposure 
durations. EPA considers the entire toxicity data base, and based on 
the effects seen for different durations and routes of exposure, 
determines which risk assessments should be done to assure that the 
public is adequately protected from any pesticide exposure scenario. 
Both short and long durations of exposure are always considered. 
Typically, risk assessments include ``acute,'' ``short-term,'' 
``intermediate term,'' and ``chronic'' risks. These assessments are 
defined by the Agency as follows.
    Acute risk, by the Agency's definition, results from 1-day 
consumption of food and water, and reflects toxicity which could be 
expressed following a single oral exposure to the pesticide residues. 
High end exposure to the pesticide residues from treated food and 
contaminated drinking water is typically assumed.
    Short-term risk results from exposure to the pesticide for a period 
of 1-7 days, and therefore overlaps with the acute risk assessment. 
Historically, this risk assessment was intended to address primarily 
dermal and inhalation exposure which could result, for example, from 
residential pesticide applications. However, since enaction of the Food 
Quality Protection Act of 1996 (FQPA), this assessment has been 
expanded to include both dietary and non-dietary sources of exposure, 
and will typically consider exposure from food, water, and residential 
uses when reliable data are available. In this assessment, risks from 
average food and water exposure, and high-end residential exposure, are 
aggregated. High-end exposures from all three sources are not typically 
added because of the very low probability of this occurring in most 
cases, and because the other conservative assumptions built into the 
assessment assure adequate protection of public health. However, for 
cases in which high-end exposure

[[Page 26475]]

can reasonably be expected from multiple sources (e.g. frequent and 
widespread homeowner use in a specific geographical area), multiple 
high-end risks will be aggregated and presented as part of the 
comprehensive risk assessment/characterization. Since the toxicological 
endpoint considered in this assessment reflects exposure over a period 
of at least 7 days, an additional degree of conservatism is built into 
the assessment; i.e., the risk assessment nominally covers 1-7 days 
exposure, and the toxicological endpoint/NOEL is selected to be 
adequate for at least 7 days of exposure. (Toxicity results at lower 
levels when the dosing duration is increased.)
    Intermediate-term risk results from exposure for 7 days to several 
months. This assessment is handled in a manner similar to the short-
term risk assessment.
    Chronic risk assessment describes risk which could result from 
several months to a lifetime of exposure. For this assessment, risks 
are aggregated considering average exposure from all sources for 
representative population subgroups including infants and children.

B. Aggregate Exposure

    In examining aggregate exposure, FFDCA section 408 requires that 
EPA take into account available and reliable information concerning 
exposure from the pesticide residue in the food in question, residues 
in other foods for which there are tolerances, residues in groundwater 
or surface water that is consumed as drinking water, and other non-
occupational exposures through pesticide use in gardens, lawns, or 
buildings (residential and other indoor uses). Dietary exposure to 
residues of a pesticide in a food commodity are estimated by 
multiplying the average daily consumption of the food forms of that 
commodity by the tolerance level or the anticipated pesticide residue 
level. The Theoretical Maximum Residue Contribution (TMRC) is an 
estimate of the level of residues consumed daily if each food item 
contained pesticide residues equal to the tolerance. In evaluating food 
exposures, EPA takes into account varying consumption patterns of major 
identifiable subgroups of consumers, including infants and children. 
The TMRC is a ``worst case'' estimate since it is based on the 
assumptions that food contains pesticide residues at the tolerance 
level and that 100% of the crop is treated by pesticides that have 
established tolerances. If the TMRC exceeds the RfD or poses a lifetime 
cancer risk that is greater than approximately one in a million, EPA 
attempts to derive a more accurate exposure estimate for the pesticide 
by evaluating additional types of information (anticipated residue data 
and/or percent of crop treated data) which show, generally, that 
pesticide residues in most foods when they are eaten are well below 
established tolerances.

II. Aggregate Risk Assessment and Determination of Safety

    Consistent with section 408(b)(2)(D), 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 
bromoxynil and to make a determination on aggregate exposure, 
consistent with section 408(b)(2), for tolerances for bromoxynil and 
DBHA on undelinted cottonseed at 1.5 ppm; cotton gin byproducts at 7.0 
ppm; and cotton hulls at 5.0 ppm; in or on cattle, hogs, horses, goats, 
and sheep at 0.5 ppm in meat, 3.5 ppm in meat by-products (mbyp), and 
1.0 ppm in fat; at 0.1 ppm in milk; at 0.05 ppm in eggs; at 0.05 ppm in 
poultry meat and fat; and at 0.3 ppm in poultry mbyp. EPA's assessment 
of the dietary exposures and risks associated with establishing the 
tolerances 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. The nature of the toxic effects caused by bromoxynil are 
discussed in the proposed rule (May 2, 1997, 62 FR 24065).

B. Toxicological Endpoints

    The toxicological endpoints for bromoxynil are discussed in Unit 
IV. ``Dose Response Assessment'' of the proposed rule for last year's 
tolerance (May 2, 1997, 62 FR 24065).

C. Exposures and Risks

    1. From food and feed uses. Tolerances have been established (40 
CFR 180.324) for the residues of bromoxynil, in or on a variety of raw 
agricultural commodities. Tolerances for the residues of bromoxynil, 
resulting from the application of octanoic and heptanoic acid esters of 
bromoxynil to cotton, have been established in or on cattle, hogs, 
horses, goats, and sheep at 0.5 ppm in meat, 3.0 ppm in mbyp, and 1.0 
ppm in fat. Tolerances for residues of bromoxynil, resulting from the 
application of octanoic and heptanoic acid esters of bromoxynil to 
cotton have been established at 0.1 ppm in milk; and at 0.05 ppm in 
eggs; at 0.05 ppm in poultry meat, mbyp, and fat. Risk assessments were 
conducted by EPA to assess dietary exposures and risks from bromoxynil 
as follows:
    i.  Acute exposure and risk. Acute dietary 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 one day or single exposure. A revised acute dietary risk 
assessment was conducted for bromoxynil. This revised acute dietary 
assessment differs from the assessment used for last year's tolerance 
as follows: (a) The results of a new cotton residue study were used to 
determine anticipated bromoxynil residues; (b) a probabilistic 
assessment submitted by the registrant was used. The acute assessment 
used a NOEL of 4 milligram/kilograms body weight/day (mg/kg bw/day) 
based on developmental effects with the population subgroup of concern 
being females <gr-thn-eq>13 years old and a NOEL of 8 mg/kg bw/day 
based on systemic effects for all populations except females 
<gr-thn-eq>13 years old. The acute analysis estimates the distribution 
of single-day exposures for the overall U.S. population and certain 
subgroups. The MOE is a measure of how closely the exposure comes to 
the NOEL and is calculated as a ratio of the NOEL to the exposure. The 
calculated MOE for acute risk of bromoxynil for the general U. S. 
Population is >58,000 and for females <gr-thn-eq>13 years old is 
>24,000. For the most exposed subgroups, the calculated MOE for acute 
risk of bromoxynil is >32,000 for non-nursing infants, >36,000 for all 
infants, and >35,000 for children 1-6 years old. These figures are 
above the required MOE of 1,000 for females <gr-thn-eq>13 years old and 
100 for the general population and all other population subgroups, 
indicating that the potential for an adverse effect from a single day 
exposure is unlikely. The level of concern for the general U.S. 
population and all population subgroups except for females 
<gr-thn-eq>13 years is based on interspecies extrapolation (10x) and 
intraspecies variability (10x). For females <gr-thn-eq>13 years, an 
added factor of 10x is used pursuant to section 408(b)(2)(C) (See Unit 
II.E.b. of this document).
    ii. Chronic exposure and risk. For chronic exposure to bromoxynil, 
the reference dose (0.015 mg/kg/day) is based upon a NOEL/LOEL of 1.5 
mg/kg/day, from a 1-year canine study, with additional uncertainty 
factors applied

[[Page 26476]]

for intra- (10x) and interspecies (10x) variability.
    A DRES chronic exposure analysis was conducted using anticipated 
residue levels for all registered commodities and livestock, and 
percent crop treated information to estimate dietary exposure for the 
general population and several population subgroups. The chronic 
analysis showed that for chronic effects other than cancer, for all 
population subgroups, less than 1% of the reference dose was consumed.
    When EPA establishes, modifies, or leaves in effect a tolerance, 
section 408(b)(2)(E) authorizes EPA to use available data and 
information on the anticipated residue levels of pesticide residues in 
food and the actual levels of pesticide chemicals that have been 
measured in food. If EPA relies on such information, EPA must require 
that data be provided five years after the tolerance is established, 
modified, or left in effect, demonstrating that the levels in food are 
not above the levels anticipated. As required by section 408(b)(2)(E), 
EPA will issue a data call-in for information relating to anticipated 
residues to be submitted no later than five years from the date of 
issuance of this tolerance.
    Section 408(b)(2)(F) states that the Agency may use data on the 
actual percent of food treated for assessing chronic dietary risk only 
if the Agency can make the following findings: (a) That 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 such pesticide 
residue; (b) that the exposure estimate does not underestimate exposure 
for any significant subpopulation group; and (c) if 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 percent crop treated as required by the section 
408(b)(2)(F), EPA may require registrants to submit data on percent 
crop treated.
    The Agency used percent crop treated (PCT) information as follows. 
A routine chronic dietary exposure analysis for bromoxynil was based on 
10% of the cotton crop treated, 10% of all cereal grain crops (wheat, 
corn, oats, barley, rye, sorghum) treated, 62% of the onion crop 
treated, 100% of the garlic crop treated, and 71% of peppermint and 
spearmint crop treated. PCT of 10% for cotton was based on the 
petitioner's request that the Agency permit up to 1.3 million acres of 
cotton to be treated annually with bromoxynil, which amounts to 10% of 
the cotton crop grown in the U.S. The registration of bromoxynil will 
restrict treatment of bromoxynil on cotton to no more than 1.3 million 
acres during 1998.
    The Agency believes that the three conditions listed above have 
been met. With respect to (a), EPA finds that the PCT information 
described above for bromoxynil used on cotton is reliable and has a 
valid basis. The registration of bromoxynil will restrict treatment of 
bromoxynil on cotton to no more than 1.3 million acres during 1998. 
Before the petitioner can increase the treatment of greater than 1.3 
million acres of cotton per year, permission from the Agency must be 
obtained. For crops other than cotton, the Agency has utilized the 
latest statistical data from RFF (Resources For The Future), Doane, and 
the U.S. Department of Agriculture (USDA), the best available sources 
for such information. As to (b) and (c), regional consumption 
information and consumption information for significant subpopulations 
is 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 information on the consumption of food bearing 
bromoxynil in a particular area.
    The cancer risk from all food sources is 1.5 in a million if 10% of 
the cotton is treated. These risk estimates are based on anticipated 
residues and percent crop treated information.
    2. From drinking water. Based on the chemical characteristics and 
monitoring data, bromoxynil residues are not expected to be found in 
ground water. For the action last year (June 18, 1997, 62 FR 33019), an 
analysis of surface water based on cotton use was conducted using the 
PRZM-EXAMS computer model (Pesticide Root Zone Model Version 2.3 plus 
Exposure Analysis Modeling System Version 2.94). The maximum or peak 
estimated concentration for bromoxynil was 12.3 parts per billion (ppb) 
and the maximum estimated long-term mean was 0.24 ppb (based on 
modeling using 36 years of weather data). These values represent what 
might be expected in a small water body near a cotton field highly 
prone to runoff. The maximum peak estimated concentration for 
bromoxynil from the model correlates with the highest value detected in 
the U.S. Geological Survey (USGS) monitoring data, 12.2 ppb, which has 
been corrected for an analytical recovery rate of 50%. For this action, 
the Agency has reevaluated the concentrations of bromoxynil in surface 
water to be used to assess risk associated with drinking water. EPA 
reviewed USGS national monitoring data and determined which of these 
sites were likely to have bromoxynil use. To estimate a reasonable high 
end exposure, EPA focussed on the calculated time weighted annual mean 
concentrations of bromoxynil at each of 11 USGS monitoring sites, which 
the EPA views as located in watersheds likely to have bromoxynil use. 
(These values were not corrected for the analytical recovery rate of 
50%.) These time weighted annual mean concentrations ranged from 0.011 
ppb to 0.18 ppb, with 10 out of the 11 sites with time weighted annual 
mean concentrations below 0.05 ppb. Six of the 10 sites had time 
weighted annual mean concentrations at or below 0.014 ppb. The highest 
annual time-weighted mean (0.18 ppb) was located in a relatively small 
watershed (approximately 100 square miles) and a relatively small water 
body, and the calculated annual mean value at this site was 
significantly influenced by the presence of a single high value (the 
highest value found in all of the available monitoring data). Based on 
this information, EPA believes that 0.05 ppb is a reasonable high end 
estimate for purposes of estimating drinking water exposure. However, 
EPA is imposing surface water monitoring requirements as a condition of 
registration to allow use of more precise estimates in the future.
    i. Acute exposure and risk. Acute drinking water exposure was 
calculated by multiplying the estimated concentration of bromoxynil in 
surface water (12.3 ppb) by the estimated water consumption (2 liters 
for adults, 1 liter for children) and then dividing by body weight (70 
kg for males, 60 kg for females, and 10 kg for children). Acute 
drinking water exposure is calculated to be 3.5 x 10<SUP>-4</SUP> mg/
kg/day for adult males and females, and 1.2 x 10<SUP>-4</SUP> mg/kg/day 
for children. The MOE for drinking water for all three population 
subgroups is >10,000.
    ii. Chronic exposure and risk. Chronic drinking water risk was 
calculated in the same way as acute risk, except that

[[Page 26477]]

the estimated mean concentrations of 0.24 ppb, 0.05 ppb, and 0.01 ppb 
were used. At 0.24 ppb, the highest of these concentrations, chronic 
drinking water exposure is calculated to be 2 x 10<SUP>-5</SUP> mg/kg/
day for children, 7 x 10<SUP>-6</SUP> mg/kg/day for males, and 8 x 
10<SUP>-6</SUP> mg/kg/day for females. All of these exposures are <1% 
of the RfD of 0.015 mg/kg/day. The cancer risk (calculated based on a 
70-year lifetime) is calculated to be 8 x 10<SUP>-7</SUP> at a chronic 
water exposure concentration of 0.24 ppb, 2 x 10<SUP>-7</SUP> at a 
concentration of 0.05 ppb, and 3 x 10<SUP>-8</SUP> at a concentration 
of 0.01 ppb. The Agency has determined that a concentration of 0.05 ppb 
for bromoxynil is a reasonable high end of exposure for bromoxynil in 
surface water; therefore, the cancer risk from exposure to bromoxynil 
in drinking water is calculated at 2 x 10<SUP>-7</SUP>.
    EPA believes the estimates of bromoxynil exposure in water derived 
from the PRZM-EXAMS model, particularly the estimates pertaining to 
chronic exposure, are significantly overstated for several reasons. The 
PRZM-EXAMS model was designed to estimate exposure for ecological risk 
assessments and thus uses a scenario of a body of water approximating 
the size of a 1 hectare (2.5 acres) pond. This tends to overstate 
chronic drinking water exposure levels for the following reasons. 
First, surface water source drinking water generally comes from bodies 
of water that are substantially larger than a 1 hectare (2.5 acres) 
pond. Second, the modeled scenario also assumes that essentially the 
whole basin receives an application of the pesticide. Yet, in virtually 
all cases, basins large enough to support a drinking water facility 
will contain a substantial fraction of the area which does not receive 
the pesticide. Third, there is often at least some flow (in a river) or 
turn over (in a reservoir or lake) of the water so the persistence of 
the pesticide near the drinking water facility is usually 
overestimated. Fourth, even assuming a reservoir is directly adjacent 
to an agricultural field, the agricultural field may not be used to 
grow a crop on which the pesticide in question is registered for use. 
Fifth, the PRZM-EXAMS modeled scenario does not take into account 
reductions in residue-loading due to applications of less than the 
maximum application rate or no treatment of the crop at all (percent 
crop treated data).
    3. From non-dietary exposure. Bromoxynil is currently not 
registered for use on any residential non-food sites.
    4. Cumulative exposure to substances with common mechanism of 
toxicity. Section 408(b)(2)(D)(v) 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.'' The Agency believes that ``available 
information'' in this context might include not only toxicity, 
chemistry, and exposure data, but also scientific policies and 
methodologies for understanding common mechanisms of toxicity and 
conducting cumulative risk assessments. For most pesticides, although 
the Agency has some information in its files that may turn out to be 
helpful in eventually determining whether a pesticide shares a common 
mechanism of toxicity with any other substances, EPA does not at this 
time have the methodologies to resolve the complex scientific issues 
concerning common mechanism of toxicity in a meaningful way. EPA has 
begun a pilot process to study this issue further through the 
examination of particular classes of pesticides. The Agency hopes that 
the results of this pilot process will increase the Agency's scientific 
understanding of this question such that EPA will be able to develop 
and apply scientific principles for better determining which chemicals 
have a common mechanism of toxicity and evaluating the cumulative 
effects of such chemicals. The Agency anticipates, however, that even 
as its understanding of the science of common mechanisms increases, 
decisions on specific classes of chemicals will be heavily dependent on 
chemical specific data, much of which may not be presently available.
    Although at present the Agency does not know how to apply the 
information in its files concerning common mechanism issues to most 
risk assessments, there are pesticides as to which the common mechanism 
issues can be resolved. These pesticides include pesticides that are 
toxicologically dissimilar to existing chemical substances (in which 
case the Agency can conclude that it is unlikely that a pesticide 
shares a common mechanism of activity with other substances) and 
pesticides that produce a common toxic metabolite (in which case common 
mechanism of activity will be assumed).
    EPA does not have, at this time, available data to determine 
whether bromoxynil has a common mechanism of toxicity with other 
substances or how to include this pesticide in a cumulative risk 
assessment. Unlike other pesticides for which EPA has followed a 
cumulative risk approach based on a common mechanism of toxicity, 
bromoxynil does not appear to produce a toxic metabolite produced by 
other substances. For the purposes of this tolerance action, therefore, 
EPA has not assumed that bromoxynil has a common mechanism of toxicity 
with other substances.

C. Aggregate Risks and Determination of Safety for U.S. Population

    1. Acute risk. The MOE for all dietary sources (food plus water) is 
>16,000 for the entire U.S. population, >11,000 for females 
<gr-thn-eq>13 years old, and >5,000 for children 1-6 years old. These 
MOEs are greater than the levels of concern of 1,000 for females 
<gr-thn-eq>13 years and 100 for all other population groups. 
Accordingly, EPA concludes that there is a reasonable certainty that no 
harm will result to the general population and major identifiable 
population subgroups from aggregate acute exposure to bromoxynil.
    2. Chronic risk. Using the exposure assumptions described above, 
EPA has concluded that aggregate exposure to bromoxynil from food and 
drinking water will utilize <1% of the RfD for the U.S. population. EPA 
has also concluded that aggregate exposure to bromoxynil will utilize 
<1% of the RfD for the most highly exposed subpopulation, children 1-6 
years old (discussed below). EPA generally has no concern for exposures 
below 100% of the RfD because the RfD represents the level at or below 
which daily aggregate dietary exposure over a lifetime will not pose 
appreciable risks to human health. Accordingly, EPA concludes that 
there is a reasonable certainty that no harm will result to the general 
population and major identifiable population subgroups from aggregate 
chronic exposure to bromoxynil.

D. Aggregate Cancer Risk for U.S. Population

    The aggregate cancer risk for the U.S. population calculated for 
use of bromoxynil is 1.7 x 10<SUP>-6</SUP>. EPA believes that a risk 
estimate of this level generally represents a negligible risk, as EPA 
has traditionally applied that concept. EPA has commonly referred to a 
negligible risk as one that is at or below 1 in 1 million (1 x 
10<SUP>-6</SUP>). Quantitative cancer risk assessment is not a precise 
science. There are a significant number of uncertainties in both the 
toxicology used to derive the cancer potency of a substance and in the 
data used to measure and calculate exposure. Thus, EPA generally does 
not attach great significance to numerical estimates that differ by 
approximately a factor of 2. Therefore, EPA considers the

[[Page 26478]]

carcinogenic risk from bromoxynil to be negligible within the meaning 
of that standard as it has been traditionally applied by EPA. 
Accordingly, EPA concludes that there is a reasonable certainty that no 
harm will result to the general population and major identifiable 
population subgroups from aggregate exposure to bromoxynil. Specific 
risks to infants and children other than cancer are discussed below.

E. Aggregate Risks and Determination of Safety for Infants and Children

    1. Safety factor for infants and children-- i. In general. In 
assessing the potential for additional sensitivity of infants and 
children to residues of bromoxynil, EPA considered all available 
developmental and reproductive toxicity data. A total of 12 
developmental and 3 reproductive toxicity studies were available for 
review. These include oral prenatal developmental toxicity studies 
(four in rats, two in rabbits, and one in mice with the phenol; one in 
rats with the octanoate), dermal prenatal developmental toxicity 
studies (one each in rats and rabbits with both the phenol and the 
octanoate), and dietary two-generation reproduction studies in rats 
(two with the phenol; one with the octanoate). The developmental 
toxicity studies are designed to evaluate adverse effects on the 
developing organism resulting from maternal pesticide exposure 
gestation. Reproduction studies provide information relating to effects 
from exposure to the pesticide on the reproductive capability of mating 
animals and data on systemic toxicity.
    FFDCA section 408 provides that EPA shall apply an additional 
tenfold margin of safety for infants and children in the case of 
threshold effects to account for pre-and post-natal toxicity and the 
completeness of the database unless EPA determines that a different 
margin of safety will be safe for infants and children. Margins of 
safety are incorporated into EPA risk assessments either directly 
through use of a MOE analysis or through using uncertainty (safety) 
factors in calculating a dose level that poses no appreciable risk to 
humans. EPA believes that reliable data support using the standard 
uncertainty factor (usually 100 for combined inter- and intra-species 
variability)) and not the additional tenfold MOE/uncertainty factor 
when EPA has a complete data base under existing guidelines and when 
the severity of the effect in infants or children or the potency or 
unusual toxic properties of a compound do not raise concerns regarding 
the adequacy of the standard MOE/safety factor.
    ii. Analysis. Developmental toxicity was observed, following in 
utero exposure to bromoxynil, in multiple studies, by two routes of 
exposure, and in three species. The induction of supernumerary ribs was 
shown to be the most sensitive indicator of developmental toxicity in 
fetal rats, mice, and (in certain studies) rabbits. In EPA's 1997 
tolerance action concerning bromoxynil (62 FR 33019, June 18, 1997 ), 
EPA concluded that the children's safety factor was not necessary to 
protect the safety of infants and children. That decision rested on the 
view that, given the large number of studies available on bromoxynil, 
EPA had a high degree of certainty regarding the level at which effects 
would occur in experimental animals. Since that action, EPA revisited 
the children's safety factor decision and concluded that the safety 
factor should be retained. This revised decision is based on EPA's 
conclusion that the standard 100-fold safety factor may not be adequate 
to protect the safety of infants and children given the clear showing 
of increased susceptibility of fetuses, the steep dose response curve, 
and the demonstrated severe developmental effects at doses above the 
LOEL. Nevertheless, EPA's decision at this time remains tentative due 
to the fact that EPA has only recently sought external science review 
of its approach to the children's safety factor and also instituted an 
internal reexamination process. Given the toxicological factors noted 
above, EPA is unwilling to make safety determinations regarding this 
pesticide without using the additional tenfold safety factor.
    EPA believes that the population of concern for which the safety 
factor should be retained is the developing fetus and the endpoint of 
concern is supernumerary ribs. This endpoint, a developmental anomaly, 
results from in utero exposure. Although some systems in infants and 
children continue developing, it is unlikely that supernumerary ribs, 
even though observed across multiple species, would result from 
postnatal exposure. Since the acute dietary endpoint for females 
<gr-thn-eq>13 years old is based on developmental effects, it was 
determined that the 10-fold safety factor should be applied to the 
acute risk assessment for females <gr-thn-eq>13 years old (the 
population subgroup that is relevant to in utero exposure), but is not 
needed for children and infants. A 10-fold factor safety factor applied 
to females <gr-thn-eq>13 years old will provide additional protection 
for infants and children and ensure a reasonable certainty of no harm 
to this sensitive subpopulation.
    2. Acute risk. The MOE of >5,000 for children 1-6 years old, the 
most highly exposed subpopulation, is greater than the level of concern 
of 100. For females <gr-thn-eq>13 years old, the population subgroup 
that is most relevant to the development of in utero exposure, the MOE 
of 11,000 is greater than the level of concern of 1000. Therefore acute 
risk for children does not trigger any concerns.
    3. Chronic risk. Using the exposure assumptions described above, 
EPA has concluded that aggregate exposure to bromoxynil from food will 
utilize <1% of the RfD for infants and children. EPA generally has no 
concern for exposures below 100% of the RfD because the RfD represents 
the level at or below which daily aggregate dietary exposure over a 
lifetime will not pose appreciable risks to human health. Therefore, 
the Agency concludes that there is a reasonable certainty of no harm to 
infants and children as a result of chronic dietary exposure to 
bromoxynil.

III. Other Considerations

A. Metabolism In Plants and Animals

    The nature (metabolism) of bromoxynil residues in plants and 
livestock is adequately understood for the purposes of these 
tolerances. In all the plant and animal (poultry and ruminants) 
metabolism studies submitted, the residues of concern were parent 
bromoxynil and the metabolite DBHA. The tolerances for cotton 
commodities and livestock are expressed in terms of bromoxynil and 
DBHA.
    Pending receipt of additional metabolism data for DBHA in 
livestock, the Agency has assumed that DBHA is of equal toxicity to the 
parent and translates proportionately to the parent for livestock 
commodities. The Agency believes these assumptions are adequately 
protective for purposes of these tolerances.

B. Analytical Enforcement Methodology

     Adequate analytical methodology is available for data collection 
and tolerance enforcement for bromoxynil per se in plants. Method I in 
PAM, Vol. II, is a GLC/MCD that has undergone a successful EPA method 
validation on wheat grain. This method involves alkaline hydrolysis in 
methanolic KOH to convert residues to bromoxynil, cleanup by liquid-
liquid partitioning, methylation using diazomethane, further cleanup on 
a Florisil column, and determination by GLC/MCD. Method Ia is the same 
method, but uses GC/ECD for determination of methylated bromoxynil.

[[Page 26479]]

    The analytical method ``Bromoxynil: Method of Analysis for 
Bromoxynil and its Metabolite, 3,5-Dibromo-4-hydroxybenzoic Acid in 
Cottonseed, Gin Trash, and Seed Processed Fractions using GC-MSD.'' 
(Method RES9603) has been the subject of an Independent Laboratory 
Validation (ILV) and an Agency Petition Method Validation (PMV). The 
method validation data are being reviewed by the Agency; approval of 
the method for enforcement purposes is anticipated.
    Method A is a GC/MCD or ECD method for the analysis of bromoxynil 
per se 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. A method for DBHA in animal 
commodities has been developed and is currently in the process of 
review and validation by the Agency.

C. Magnitude of Residues

    In the petition for these tolerances, the registrant requested that 
40 CFR 180.324 be amended by establishing tolerances for residues of 
the herbicide bromoxynil and its metabolite DBHA on cotton at 7 ppm for 
undelinted cottonseed, 50 ppm for cotton gin byproducts, and 21 ppm for 
cotton hulls. These proposed tolerances are the same as those issued in 
the June 18, 1997 final rule (62 FR 33019). Immediately prior to 
establishing these tolerances, the registrant reduced the maximum label 
rate as a result of Agency risk concerns. The tolerances were 
determined by extrapolating from residue studies conducted at the 
former maximum label rate (4.5 lb ai/A). Following the submission of 
the tolerance petition, the registrant submitted residue data for 
bromoxynil and DBHA in cotton commodities at the revised maximum 
application rate of 3 applications at 0.5 lb ai/A each for a total of 
1.5 lb ai/A. These data show that bromoxynil and DBHA residues in 
cotton commodities are lower than the values determined for the June 
18, 1997 final rule. Based on the new residue data, tolerances for 
bromoxynil and DBHA in cotton commodities are being changed to 7.0 ppm 
in cotton gin byproducts, 5.0 ppm in cotton hulls, and 1.5 ppm in 
undelinted cottonseed.
    In the June 18, 1997 final rule, tolerances for livestock 
commodities (including milk and eggs) were expressed as bromoxynil per 
se only; the Agency concluded that measurement of bromoxynil per se in 
livestock commodities could serve as a marker to indicate the amount of 
DBHA present in livestock. After further consideration, the Agency has 
determined that measurement of bromoxynil per se in livestock is not 
adequate to determine the amount of DBHA present. Therefore, in this 
action, tolerances are expressed as bromoxynil and DBHA instead of only 
as bromoxynil per se in livestock.
    Tolerances for ruminant commodities (meat, fat, and meat by 
products) were recalculated since issuing the June 18, 1997 final rule 
due to new information. First, new residue data for bromoxynil and DBHA 
in cotton commodities were used to determine expected maximum 
theoretical dietary exposure to bromoxynil and DBHA via ingestion of 
cotton commodities. Second, maximum theoretical residues in livestock 
commodities were recalculated based on a revision in the dosing levels 
used in livestock feeding studies. Doses were previously calculated in 
terms of bromoxynil octanoate; however, since tolerances in RACs (raw 
agricultural commodities) are for bromoxynil per se, doses were 
recalculated as such. Finally, changes were made to the relative 
contributions of feed items in the diet as a result of grazing 
restrictions for grass, and information provided by the registrant on 
the amount of cotton gin trash in beef and dairy cattle diets. These 
changes did not affect tolerances for residues in milk, eggs, or meat 
and fat of ruminants and poultry; however, the tolerances for residues 
in meat by-products increased to 3.5 ppm for ruminants and to 0.3 ppm 
for poultry.

D. International Residue Limits

    There are no established or proposed Codex MRLs for bromoxynil 
residues.

E. Rotational Crop Restrictions

    Required additional limited field rotational crop studies have not 
been submitted to the Agency; acceptable studies previously submitted 
in support of reregistration reflect a maximum seasonal and single 
application rate of 0.5 lb ai/A, but the use on cotton constitutes a 
maximum seasonal application rate of 1.5 lb ai/A. Pending receipt of 
these studies registered labels must restrict rotation of cotton fields 
treated at a rate of greater than 0.5 lb ai/A/season to cotton.

IV. Conclusion

    Therefore, tolerances are established for bromoxynil and DBHA in 
undelinted cottonseed at 1.5 ppm, cotton gin byproducts at 7.0 ppm, and 
cotton hulls at 5.0 ppm. In addition, this document establishes 
tolerances for the residues of bromoxynil and DBHA, resulting from the 
application of octanoic and heptanoic acid esters of bromoxynil to 
cotton, in or on cattle, hogs, horses, goats, and sheep to 0.5 ppm in 
meat, 3.5 ppm in mbyp, and 1.0 ppm in fat. Further, this document 
establishes tolerances for residues of bromoxynil and DBHA, resulting 
from the application of octanoic and heptanoic acid esters of 
bromoxynil to cotton, at 0.1 ppm in milk; at 0.05 ppm in eggs; at 0.05 
ppm in poultry meat and fat; and at 0.3 ppm in poultry mbyp.

V. Objections and Hearing Requests

    The new FFDCA section 408(g) provides essentially the same process 
for persons to ``object'' to a tolerance regulation issued by EPA under 
new section 408(e) and (l)(6) as was provided in the old section 408 
and in section 409. However, the period for filing objections is 60 
days, rather than 30 days. EPA currently has procedural regulations 
which govern the submission of objections and hearing requests. These 
regulations will require some modification to reflect the new law. 
However, until those modifications can be made, EPA will continue to 
use those procedural regulations with appropriate adjustments to 
reflect the new law.
    Any person may, by July 13, 1998, file written objections to any 
aspect of this regulation and may also request a hearing on those 
objections. Objections and hearing requests must be filed with the 
Hearing Clerk, at the address given above (40 CFR 178.20). A copy of 
the objections and/or hearing requests filed with the Hearing Clerk 
should be submitted to the OPP docket for this rulemaking. The 
objections submitted must specify the provisions of the regulation 
deemed objectionable and the grounds for the objections (40 CFR 
178.25). Each objection must be accompanied by the fee prescribed by 40 
CFR 180.33(i). If a hearing is requested, the objections must include a 
statement of the factual issues on which a hearing is requested, the 
requestor's contentions on such issues, and a summary of any evidence 
relied upon by the requestor (40 CFR 178.27). A request for a hearing 
will be granted if the Administrator determines that the material 
submitted shows the following: There is genuine and substantial issue 
of fact; there is a reasonable possibility that available evidence 
identified by the requestor would, if established, resolve one or more 
of such issues in favor of the requestor, taking into account 
uncontested claims or facts to the contrary; and resolution of the 
factual issues in the manner sought by the requestor would be adequate 
to justify the action requested (40 CFR 178.32).

[[Page 26480]]

Information submitted in connection with an objection or hearing 
request may be claimed confidential by marking any part or all of that 
information as CBI. Information so marked will not be disclosed except 
in accordance with procedures set forth in 40 CFR part 2. A copy of the 
information that does not contain CBI must be submitted for inclusion 
in the public record. Information not marked confidential may be 
disclosed publicly by EPA without prior notice.

VI. Public Docket

    EPA has established a record for this rulemaking under docket 
control number [OPP-300661] (including any comments and data submitted 
electronically). A public version of this record, including printed, 
paper versions of electronic comments, which does not include any 
information claimed as CBI, is available for inspection from 8:30 a.m. 
to 4 p.m., Monday through Friday, excluding legal holidays. The public 
record is located in Room 119 of the Public Information and Records 
Integrity Branch, Information Resources and Services Division (7502C), 
Office of Pesticide Programs, Environmental Protection Agency, Crystal 
Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
    Electronic comments may be sent directly to EPA at:
    opp-docket@epamail.epa.gov.


    Electronic comments must be submitted as an ASCII file avoiding the 
use of special characters and any form of encryption.
    The official record for this rulemaking, as well as the public 
version, as described above will be kept in paper form. Accordingly, 
EPA will transfer any copies of objections and hearing requests 
received electronically into printed, paper form as they are received 
and will place the paper copies in the official rulemaking record which 
will also include all comments submitted directly in writing. The 
official rulemaking record is the paper record maintained at the 
Virginia address in ``ADDRESSES'' at the beginning of this document.

VII. Regulatory Assessment Requirements

    This final rule establishes tolerances under FFDCA section 408(d) 
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). This final rule does not contain 
any information collections subject to OMB approval under the Paperwork 
Reduction Act (PRA), 44 U.S.C. 3501 et seq., or impose any enforceable 
duty or contain any unfunded mandate as described under Title II of the 
Unfunded Mandates Reform Act of 1995 (UMRA) (Pub. L. 104-4). Nor does 
it require any prior consultation as specified by Executive Order 
12875, entitled Enhancing the Intergovernmental Partnership (58 FR 
58093, October 28, 1993), or special considerations as required by 
Executive Order 12898, entitled Federal Actions to Address 
Environmental Justice in Minority Populations and Low-Income 
Populations (59 FR 7629, February 16, 1994), or require OMB review in 
accordance with Executive Order 13045, entitled Protection of Children 
from Environmental Health Risks and Safety Risks (62 FR 1985, April 23, 
1997).
    In addition, since these tolerances and exemptions that are 
established on the basis of a petition under FFDCA section 408(d), such 
as the tolerances in this final rule, do not require the issuance of a 
proposed rule, the requirements of the Regulatory Flexibility Act (RFA) 
(5 U.S.C. 601 et seq.) do not apply. Nevertheless, the Agency has 
previously assessed whether establishing tolerances, exemptions from 
tolerances, raising tolerance levels or expanding exemptions might 
adversely impact small entities and concluded, as a generic matter, 
that there is no adverse economic impact. The factual basis for the 
Agency's generic certification for tolerance actions published on May 
4, 1981 (46 FR 24950) and was provided to the Chief Counsel for 
Advocacy of the Small Business Administration.

VIII. Submission to Congress and the General Accounting Office

    Under 5 U.S.C. 801(a)(1)(A), as added by the Small Business 
Regulatory Enforcement Fairness Act of 1996, the Agency has submitted 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 General Accounting Office prior to publication of this rule in 
today's Federal Register. This 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 6, 1998.

James Jones,
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. 346a and 371.

    2. In Sec. 180.324, paragraph (a) is revised to read as follows:


Sec. 180.324  Bromoxynil; tolerances for residues.

    (a) General. (1) Tolerances are established for residues of the 
herbicide bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) resulting from 
application of its octanoic and/or heptanoic acid ester in or on the 
following commodities:

                                                                        
------------------------------------------------------------------------
                 Commodity                        Parts per million     
------------------------------------------------------------------------
Alfalfa, seeding..........................  0.1 ppm                     
Barley, grain.............................  0.1 ppm                     
Barley, straw.............................  0.1 ppm                     
Corn, fodder (dry)........................  0.1 ppm                     
Corn, fodder (green)......................  0.1 ppm                     
Corn, fodder, field (dry).................  0.1 ppm                     
Corn, fodder, field (green)...............  0.1 ppm                     
Corn, grain...............................  0.1 ppm                     
Corn, grain, field........................  0.1 ppm                     
Flaxseed..................................  0.1 ppm                     
Flax straw................................  0.1 ppm                     
Garlic....................................  0.1 ppm                     
Grass, canary, annual, seed...............  0.1 ppm                     
Grass, canary, annual, straw..............  0.1 ppm                     
Mint hay..................................  0.1 ppm                     
Oats, forage, green.......................  0.1 ppm                     
Oats, grain...............................  0.1 ppm                     
Oats, straw...............................  0.1 ppm                     
Onions (dry bulb).........................   0.1 ppm                    
Rye, forage, green........................  0.1 ppm                     
Rye, grain................................  0.1 ppm                     
Rye, straw................................  0.1 ppm                     
Sorghum, fodder...........................  0.1 ppm                     
Sorghum, forage...........................  0.1 ppm                     
Sorghum, grain............................  0.1 ppm                     
Wheat, forage, green......................  0.1 ppm                     
Wheat, grain..............................  0.1 ppm                     
Wheat, straw..............................  0.1 ppm                     
------------------------------------------------------------------------

    (2) Tolerances are established for residues of the herbicide 
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 in or on the following 
commodities:

[[Page 26481]]



                                                                        
------------------------------------------------------------------------
                 Commodity                        Parts per million     
------------------------------------------------------------------------
Cattle, fat...............................  1 ppm                       
Cattle, mbyp..............................  3.5 ppm                     
Cattle, meat..............................  0.5 ppm                     
Cotton gin byproducts.....................  7.0 ppm                     
Cotton, hulls.............................  5.0 ppm                     
Cotton, undelinted seed...................  1.5 ppm                     
Eggs......................................  0.05 ppm                    
Goats, fat................................  1 ppm                       
Goats, mbyp...............................  3.5 ppm                     
Goats, meat...............................  0.5 ppm                     
Hogs, fat.................................  1 ppm                       
Hogs, mbyp................................  3.5 ppm                     
Hogs, meat................................  0.5 ppm                     
Horses, fat...............................  1 ppm                       
Horses, mbyp..............................  3.5 ppm                     
Horses, meat..............................  0.5 ppm                     
Milk......................................  0.1 ppm                     
Poultry, fat..............................  0.05 ppm                    
Poultry, mbyp.............................  0.3 ppm                     
Poultry, meat.............................  0.05 ppm                    
Sheep, fat................................  1 ppm                       
Sheep, mbyp...............................  3.5 ppm                     
Sheep, meat...............................  0.5 ppm                     
------------------------------------------------------------------------

* * * * *

[FR Doc. 98-12639 Filed 5-8-98; 9:42 am]
BILLING CODE 6560-50-F