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 Environmental Protection Agency 40 CFR Part 180
[OPP-301128; FRL-6781-5]
RIN 2070-AB78
 AGENCY: Environmental Protection Agency (EPA).
 ACTION: Final rule.
 SUMMARY: This regulation establishes a tolerance for residues of prohexadione calcium (calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate) in or on grass forage, grass hay, grass straw and grass seed screenings.   K-I Chemical U.S.A. Inc. requested these tolerances under the Federal Food, Drug, and Cosmetic Act, as amended by the Food Quality Protection Act of 1996.
 DATES: This regulation is effective June 1, 2001.  Objections and requests for hearings, identified by docket control number OPP-301128, must be received by EPA on or before July 31, 2001.
 ADDRESSES: Written objections and hearing requests may be submitted by mail, in person, or by courier.  Please follow the detailed instructions for each method as provided in Unit VI. of the
                        **SUPPLEMENTARY INFORMATION**
                        . To ensure proper receipt by EPA, your objections and hearing requests must identify docket control number OPP-301128 in the subject line on the first page of your response.
 FOR FURTHER INFORMATION CONTACT: By mail:  Cynthia Giles-Parker (PM 22), Registration Division (7505C), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460; telephone number: (703) 305-7740; and e-mail address: giles-parker.cynthia@epa.gov.


SUPPLEMENTARY INFORMATION: I. General Information A.  Does this Action Apply to Me? You may be affected by this action if you are an agricultural producer, food manufacturer, or pesticide manufacturer.  Potentially affected categories and entities may include, but are not limited to: Categories
NAICS codes
Examples of Potentially Affected EntitiesIndustry
111
Crop production112
Animal production311
Food manufacturing32532
Pesticide manufacturing
 This listing is not intended to be exhaustive, but rather provides  a guide for readers regarding entities likely to be affected by this action.  Other types of entities not listed in the table could also be affected.  The North American Industrial Classification System (NAICS) codes have been provided to assist you and others in determining whether or not this action might apply to certain entities.  If you have 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 Additional Information, Including Copies of this Document and Other Related Documents? 1. 
                    *Electronically*.  You may obtain electronic copies of this document, and certain other related documents that might be available electronically, from the EPA Internet Home Page at http://www.epa.gov/​.  To access this document, on the Home Page select “Laws and Regulations,” “Regulations and Proposed Rules,” and then look up the entry for this document under the “
                    **Federal Register**
                    —Environmental Documents.”  You can also go directly to the
                    **Federal Register**
                     listings at http://www.epa.gov/​fedrgstr/​.  To access the OPPTS Harmonized Guidelines referenced in this document, go directly to the guidelines at http://www.epa.gov/​opptsfrs/​home/​guidelin.htm. 2. 
                    *In person*. The Agency has established an official record for this action under docket control number OPP-301128.  The official record consists of the documents specifically referenced in this action, and other information related to this action, including any information claimed as Confidential Business Information (CBI).  This official record includes the documents that are physically located in the docket, as well as the documents that are referenced in those documents.  The public version of the official record does not include any information claimed as CBI.  The public version of the official record, which includes printed, paper versions of any electronic comments submitted during an applicable comment period is available for inspection in the Public Information and Records Integrity Branch (PIRIB), 
                    ( print page 29706)
                    Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA, from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The PIRIB telephone number is (703) 305-5805. II.  Background and Statutory Findings In the 
                    **Federal Register**
                     of  March 28, 2001 (66 FR 16921) (FRL-6769-9), EPA issued a notice pursuant to section 408 of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a as amended by the Food Quality Protection Act of 1996 (FQPA) (Public Law 104-170) announcing the filing of a pesticide petition (PP) for tolerance by K-I Chemical U.S.A. Inc., Westchester Financial Center, 11 Martine Avenue, 9th Floor, White Plains, NY, 10606. This notice included a summary of the petition prepared by K-I Chemical U.S.A. Inc., the registrant. There were no comments received in response to the notice of filing. The petition requested that 40 CFR 180.547 be amended by establishing a tolerance for residues of the plant growth regulator prohexadione calcium, calcium 3-oxido-5-oxo-4- propionylcyclohex-3-enecarboxylate in or on grass forage at 0.10 part per million (ppm), grass hay at  0.10 ppm, grass straw at 1.2 ppm and grass seed screenings at 3.5 ppm. 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. For further discussion of the regulatory requirements of section 408 and a complete description of the risk assessment process, see the final rule on Bifenthrin Pesticide Tolerances (62 FR 62961, November 26, 1997) (FRL-5754-7). III. 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 and to make a determination on aggregate exposure, consistent with section 408(b)(2), for a tolerance for residues of prohexadione calcium, calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate in or on grass forage at 0.10 ppm, grass hay at  0.10 ppm, grass straw at 1.2 ppm and grass seed screenings at 3.5 ppm. EPA's assessment of exposures and risks associated with establishing the tolerance 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 prohexadione calcium are discussed in the following Table 1 as well as the no observed adverse effect level (NOAEL) and the lowest observed adverse effect level (LOAEL) from the toxicity studies reviewed. **Table 1.—Subchronic, Chronic, and Other Toxicity**
Guideline No./ Study Type
Results870.3100 90-Day oral toxicity rodents (rat)
NOAEL: Males: 73.1 mg/kg/day; Females: 80.4 mg/kg/day  LOAEL: Males: 734 mg/kg/day; Females: 815 mg/kg/day based on squamous cell hyperplasia of the forestomach.870.3100 90-Day oral toxicity rodents (mouse)
NOAEL: Males: ≥10,244 mg/kg/day; Females: ≥11,916 mg/kg/day (highest dose tested)LOAEL:  Males: >10,244 mg/kg/day; Females: >11,916 mg/kg/day870.3150 90-Day oral toxicity in nonrodents (dog)
NOAEL = 80 mg/kg/day  LOAEL = 400 mg/kg/day based on moderate cortical areas of dilated basophilic tubules in the kidneys and decreased potassium levels.870.3200  21/28-Day dermal toxicity
DATA GAP870.3250  90-Day dermal toxicity
NA870.3700a Prenatal developmental toxicity in rodents (rat)
Maternal NOAEL ≥1,000 mg/kg/day (limit dose)LOAEL = Not observed  Developmental NOAEL ≥1,000 mg/kg/day (limit dose)  LOAEL = Not observed870.3700b  Prenatal developmental toxicity in nonrodents (rabbit)
Maternal NOAEL = 40 mg/kg/day LOAEL = 200 mg/kg/day based on increased mortality,abortions, and decreased maternal body weight gain.Developmental NOAEL ≥200 mg/kg/day  LOAEL = Not observed(Due to severe mortality at 750 mg/kg/day, 200 mg/kg/day was deemed the high dose for evaluation)870.3700b  Prenatal developmental toxicity in nonrodents (rabbit)
Maternal NOAEL = ≥150 mg/kg/day  LOAEL = Not observed  Developmental NOAEL ≥150 mg/kg/day  LOAEL = Not observed( print page 29707)870.3700b  Prenatal developmental toxicity in nonrodents (rabbit)
Maternal NOAEL = 100 mg/kg/day LOAEL = 350 mg/kg/day based on premature deliveries.Developmental NOAEL ≥350 mg/kg/day  LOAEL = Not observed870.3800 2-Generation Reproduction and fertility effects rats
Parental/Systemic NOAEL = 35.5 mg/kg/day LOAEL = 385 mg/kg/day based on increased mortality.Reproductive NOAEL ≥3,850 mg/kg/day LOAEL >3,850 mg/kg/day Offspring NOAEL = 385 mg/kg/day LOAEL = 3850 mg/kg/day based on decreased pup body weight.870.4100  Chronic toxicity dogs
NOAEL = 20 mg/kg/day  LOAEL = 200 mg/kg/day based on histopathological changes in the kidneys and increased urinary volume and sodium concentrations.870.4300  Chronic toxicity/carcinogenicity rats
NOAEL = 93.9 mg/kg/day LOAEL = 469 mg/kg/day based on decreased WBC in males.No evidence of carcinogenicity870.4200  Carcinogenicity mice
NOAEL =  279 mg/kg/day LOAEL = 2847 mg/kg/day based on decreased body weight gain and food utilization and microscopic changes in the stomachs of males.No evidence of carcinogenicity870.5100  Bacterial reverse mutation assay (Ames test)
Negative with and without S-9 activation up to the highest dose tested (5,000 μg/plate).870.5300
                            *In vitro*
                             mammalian gene mutation assay
Negative with S-9 activation up to 475 μg/mL.  Negative without S-9 activation up to 500 μg/mL.  Compound tested to concentrations limited by solubility.870.5375
                            *In vitro*
                             mammalian chromosome aberration (Chinese Hampster Ovary (CHO) cells)
Increase in polyploidy in the absence of S9 activation at 500 μg/mL for 6 hours at the 24-hour cell harvest time;effect not observed after treatments of 24-or 48-hours.  No increase in aberration frequency at any concentration or harvest time with or without S9.  Compound was tested up to concentrations limited by solubility.870.5385 
                            *In vivo*
                            mammalian chromosome aberration (rat bone marrow cells)
Negative at 6, 24, and 48-hour sacrifices.  Compound tested to the limit dose.870.5395  Mammalian erythrocyte micronucleus test
Negative at 24, 48, and 72 hour sacrifices. No increase in the frequency of micronucleated polychromatic erythrocytes in bone marrow.870.5550  UDS in primary rat hepatocytes
Negative up to cytotoxic concentration (500 μg/mL).870.5500  Rec assay with
                            *Bacillus subtilis*
Negative for DNA damage when tested up to the limit dose (5,000 μg/mL) both with and without S9.870.6200a  Acute neurotoxicity screening battery
NOAEL ≥2,000 mg/kg  LOAEL = Not observed870.6200b  Subchronic neurotoxicity screening battery
NOAEL ≥1148 (M) or 1348(F) mg/kg/day  LOAEL = Not observed870.6300  Developmental neurotoxicity
NA870.7485  Metabolism and pharmacokinetics
Following oral treatment of rats,prohexadione calcium was rapidly absorbed with highest tissue/carcass concentrations obtained within 30 minutes; however, absorption became saturated at the highest dose.The test material did not accumulate in the tissues.  For low dose animals,renal excretion was the primary route of elimination.  At the high dose, fecal excretion became the primary route of elimination.  The primary excreta(both feces and urine) metabolite was identified as the free acid.870.7600  Dermal penetration
NA
 B. Toxicological Endpoints The dose at which no adverse effects are observed (the NOAEL) from the toxicology study identified as appropriate for use in risk assessment is used to estimate the toxicological level of concern (LOC). However, the lowest dose at which adverse effects of concern are identified (the LOAEL) is sometimes used for risk assessment if no NOAEL was achieved in the toxicology study selected. An uncertainty factor (UF) is applied to reflect uncertainties inherent in the extrapolation from laboratory animal data to humans and in the variations in sensitivity among members of the human population as well as other unknowns. An UF of 100 is routinely used, 10× to account for 
                    ( print page 29708)
                    interspecies differences and 10× for intraspecies differences. For dietary risk assessment (other than cancer) the Agency uses the UF to calculate an acute or chronic reference dose (acute RfD or chronic RfD) where the RfD is equal to the NOAEL divided by the appropriate UF (RfD = NOAEL/UF). Where an additional safety factor is retained due to concerns unique to the FQPA, this additional factor is applied to the RfD by dividing the RfD by such additional factor. The acute or chronic Population Adjusted Dose (aPAD or cPAD) is a modification of the RfD to accommodate this type of FQPA Safety Factor. For non-dietary risk assessments (other than cancer) the UF is used to determine the LOC. For example, when 100 is the appropriate UF (10× to account for interspecies differences and 10× for intraspecies differences) the LOC is 100. To estimate risk, a ratio of the NOAEL to exposures (margin of exposure (MOE) = NOAEL/exposure) is calculated and compared to the LOC. The linear default risk methodology (Q*) is the primary method currently used by the Agency to quantify carcinogenic risk. The Q* approach assumes that any amount of exposure will lead to some degree of cancer risk. A Q* is calculated and used to estimate risk which represents a probability of occurrence of additional cancer cases (e.g., risk is expressed as 1 × 10-6
                     or one in a million). Under certain specific circumstances, MOE calculations will be used for the carcinogenic risk assessment. In this non-linear approach, a “point of departure” is identified below which carcinogenic effects are not expected. The point of departure is typically a  NOAEL based on an endpoint related to cancer effects though it may be a different value derived from the dose response curve. To estimate risk, a ratio of the point of departure to exposure (MOEcancer
                    = point of departure/exposures) is calculated.  A summary of the toxicological endpoints for prohexadione calcium used for human risk assessment is shown in the following Table 2: **Table 2.—Summary of Toxicological Dose and Endpoints for prohexadione calcium for Use in Human Risk Assessment**
Exposure Scenario
Dose Used in Risk Assessment, UF
FQPA SF and LOC for Risk Assessment
Study and Toxicological EffectsAcute Dietary
NA
NA
no adverse effects of concern observed in oral, developmental, and neurotoxicity studies in rats and rabbits, attributable to a single exposure doseChronic Dietary
NOAEL= 80 mg/kg/day UF = 100 Chronic RfD = 0.80 mg/kg/day
FQPA SF = 1× cPAD = chronic RfD  FQPA SF = 0.80 mg/kg/day
Subchronic & chronic toxicity-dog LOAEL = 200 mg/kg/day based on histopathological changes in the kidneys (dilated basophilic tubules) and clinical chemistry changesShort-Term Dermal (1-7 days) (Occupational/Residential)
Oral Maternal NOAEL = 100 mg/kg/day  Estimated dermal absorption rate 25%
LOC for MOE = 100  (Occupational)
Developmental toxicity- rabbit   Maternal LOAEL = 350 mg/kg/day based on premature deliveriesIntermediate-Term Dermal (1 week - several months)  (Occupational/Residential)
Oral NOAEL = 80 mg/kg/day  Estimated absorption rate 25%
LOC for MOE =100 (Occupational)
Subchronic toxicity-dog LOAEL = 400 mg/kg/day based on moderate cortical areas of dilated basophilic tubules in the kidneys and decreased potassium levelsLong-Term Dermal (several months - lifetime) (Occupational/Residential)
Oral NOAEL = 80 mg/kg/day  Estimated absorption rate 25%
LOC for MOE = 100 (Occupational)
Subchronic & chronic toxicity-dog LOAEL = 200 mg/kg/day based on histopathological changes in the kidneys (dilated basophilic tubules) and clinical chemistry changesShort-Term Inhalation (1-7 days) (Occupational/Residential)
Oral Maternal NOAEL= 100 mg/kg/day (inhalation absorption rate = 100%)
LOC for MOE = 100 (Occupational)
Developmental toxicity- rabbit  LOAEL = 350 mg/kg/day based on premature deliveriesIntermediate-Term Inhalation (1 week - several months) (Occupational/Residential)
Oral NOAEL= 80 mg/kg/day (inhalation absorption rate = 100%)
LOC for MOE = 100 (Occupational)
Subchronic toxicity-dog  LOAEL = 400 mg/kg/day based on moderate cortical areas of dilated basophilic tubules in the kidneys and decreased potassium levelsLong-Term Inhalation(several months - lifetime)(Occupational/Residential)
Oral NOAEL= 80 mg/kg/day  (inhalation absorption rate = 100%)
LOC for MOE = 100  (Occupational)
Subchronic & chronic toxicity-dog  LOAEL = 200 mg/kg/day based on histopathological changes in the kidneys (dilated basophilic tubules) and clinical chemistry changes( print page 29709)Cancer (oral, dermal, inhalation)
Not likely human carcinogen
NA
No evidence of carcinogenic potential, therefore, cancer risk assessment is not required
 C. Exposure Assessment 1. 
                    *Dietary exposure from food and feed uses*. Tolerances have been established (40 CFR 180.547) for the residues of prohexadione calcium, in or on a variety of raw agricultural commodities.  Risk assessments were conducted by EPA to assess dietary exposures from prohexadione calcium in food as follows: i. 
                    *Acute exposure*.  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.  An acute dietary risk assessment was not performed because there were no adverse effects of concern observed in neurotoxicity studies, oral toxicology studies, including maternal toxicity in the developmental toxicity studies in rats and rabbits, that were attributable to a single exposure dose. ii. 
                    *Chronic exposure*
                    . In conducting this chronic dietary risk assessment the Dietary Exposure Evaluation Model (DEEM_
                    ) analysis evaluated the individual food consumption as reported by respondents in the USDA 1989-1992 nationwide Continuing Surveys of Food Intake by Individuals (CSFII) and accumulated exposure to the chemical for each commodity. The following assumptions were made for the chronic exposure assessments: Tolerance level residues (pome fruit,  peanuts, animal feeds) and 100% CT was assumed for all commodities.  Residues were not found to concentrate in processed apples; therefore, concentration factors were not used (apple juice, cider). iii. 
                    *Cancer*.  In accordance with the EPA Draft Guidelines for Carcinogen Risk Assessment (July, 1999), prohexadione calcium is classified as not likely to be carcinogenic to humans by all routes of exposure based upon lack of evidence of carcinogenicity in rats and mice. 2. 
                    *Dietary exposure from drinking water*. The Agency lacks sufficient monitoring exposure data to complete a comprehensive dietary exposure analysis and risk assessment for prohexadione calcium in drinking water. Because the Agency does not have comprehensive monitoring data, drinking water concentration estimates are made by reliance on simulation or modeling taking into account data on the physical characteristics of prohexadione calcium. The Agency uses the Generic Estimated Environmental Concentration (GENEEC) or the Pesticide Root Zone/Exposure Analysis Modeling System (PRZM/EXAMS) to estimate pesticide concentrations in surface water and SCI-GROW, which predicts pesticide concentrations in groundwater.   In general, EPA will use GENEEC (a tier 1 model) before using PRZM/EXAMS (a tier 2 model) for a screening-level assessment for surface water. The GENEEC model is a subset of the PRZM/EXAMS model that uses a specific high-end runoff scenario for pesticides. GENEEC incorporates a farm pond scenario, while PRZM/EXAMS incorporates an index reservoir environment in place of the previous pond scenario. The PRZM/EXAMS model includes a percent crop area factor as an adjustment to account for the maximum percent crop coverage within a watershed or drainage basin. None of these models include consideration of the impact processing (mixing, dilution, or treatment) of raw water for distribution as drinking water would likely have on the removal of pesticides from the source water. The primary use of these models by the Agency at this stage is to provide a coarse screen for sorting out pesticides for which it is highly unlikely that drinking water concentrations would ever exceed human health levels of concern. Since the models used  are considered to be screening tools in the risk assessment process, the Agency does not use estimated environmental concentrations (EECs) from these models to quantify drinking water exposure and risk as a %RfD or %PAD. Instead drinking water levels of comparison (DWLOCs) are calculated and used as a point of comparison against the model estimates of a pesticide's concentration in water. DWLOCs are theoretical upper limits on a pesticide's concentration in drinking water in light of total aggregate exposure to a pesticide in food, and from residential uses. Since DWLOCs address total aggregate exposure to prohexadione calcium they are further discussed in the aggregate risk sections below. Based on the GENEEC and SCI-GROW models the estimated environmental concentrations (EECs) of prohexadione calcium for acute exposures are estimated to be 35.6 parts per billion (ppb) for surface water and 0.001 ppb for ground water. The EECs for chronic exposures are estimated to be 7.73 ppb for surface water and 0.001 ppb for ground water. 3. 
                    *From non-dietary exposure*. The term “residential exposure” is used in this document to refer to non-occupational, non-dietary exposure (e.g., for lawn and garden pest control, indoor pest control, termiticides, and flea and tick control on pets).   Prohexadione calcium is not registered for use on any sites that would result in residential exposure. 4. 
                    *Cumulative exposure to substances with a 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.” EPA does not have, at this time, available data to determine whether prohexadione calcium 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, prohexadione calcium 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 prohexadione calcium has 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 the final rule for 
                    ( print page 29710)
                    Bifenthrin Pesticide Tolerances (62 FR 62961, November 26, 1997). D. Safety Factor for Infants and Children 1. 
                    *In general*. 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 prenatal and postnatal toxicity and the completeness of the data base on toxicity and exposure 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 margin of exposure (MOE) analysis or through using uncertainty (safety) factors in calculating a dose level that poses no appreciable risk to humans. 2. 
                    *Prenatal and postnatal sensitivity*.  The prenatal and postnatal toxicology data base for prohexadione is adequate for FQPA considerations.  The results of these studies indicated no quantitative or qualitative increase in susceptibility of rats or rabbits to 
                    *in utero*
                     and/or postnatal exposure to prohexadione.  A developmental neurotoxicity study is not required. 3. 
                    *Conclusion*.  There is a complete toxicity data base for prohexadione calcium and exposure data are complete or are estimated based on data that reasonably accounts for potential exposures.  The FQPA Safety Factor is 1× (reduced from 10×).   In assessing the risk posed by prohexadione calcium  the safety factor could be removed  because:  (i)  The prenatal and postnatal toxicology data base is complete, there is no indication of increased susceptibility, and a developmental neurotoxicity study is not required, and (ii)  the food and drinking water exposure assessments will not underestimate the potential exposures for infants and children from the use of prohexadione calcium (currently there are no proposed residential uses and, therefore, non-occupational exposure is not expected). E. Aggregate Risks and Determination of Safety To estimate total aggregate exposure to a pesticide from food, drinking water, and residential uses, the Agency calculates DWLOCs which are used as a point of comparison against the model estimates of a pesticide's concentration in water (EECs). DWLOC values are not regulatory standards for drinking water. DWLOCs are theoretical upper limits on a pesticide's concentration in drinking water in light of total aggregate exposure to a pesticide in food and residential uses. In calculating a DWLOC, the Agency determines how much of the acceptable exposure (i.e., the PAD) is available for exposure through drinking water [e.g., allowable chronic water exposure (mg/kg/day) = cPAD - (average food +  residential exposure).  This allowable exposure through drinking water is used to calculate a DWLOC. A DWLOC will vary depending on the toxic endpoint, drinking water consumption, and body weights. Default body weights and consumption values as used by the USEPA Office of Water are used to calculate DWLOCs: 2L/70 kg (adult male), 2L/60 kg (adult female), and 1L/10 kg (child). Default body weights and drinking water consumption values vary on an individual basis. This variation will be taken into account in more refined screening-level and quantitative drinking water exposure assessments.  Different populations will have different DWLOCs.  Generally, a DWLOC is calculated for each type of risk assessment used: acute, short-term, intermediate-term, chronic, and cancer. When EECs for surface water and groundwater are less than the calculated DWLOCs, OPP concludes with reasonable certainty that exposures to the pesticide in drinking water (when considered along with other sources of exposure for which OPP has reliable data) would not result in unacceptable levels of aggregate human health risk at this time. Because OPP considers the aggregate risk resulting from multiple exposure pathways associated with a pesticide's uses, levels of comparison in drinking water may vary as those uses change. If new uses are added in the future, OPP will reassess the potential impacts of residues of the pesticide in drinking water as a part of the aggregate risk assessment process. 1. 
                    *Acute risk*.  Acute dietary risk assessment is not expected because there were no adverse effects of concern observed in neurotoxicity studies, oral toxicology studies, including maternal toxicity in the developmental toxicity studies in rats and rabbits, that were attributable to a single exposure dose. 2. 
                    *Chronic risk*.  Using the exposure assumptions described in this unit for chronic exposure, EPA has concluded that exposure to prohexadione calcium from food will utilize  < 1 % of the cPAD for the U.S. population, 2% of the cPAD for all infants (<1 year old) and 2% of th cPAD for children 1-6 years of age. There are no residential uses for prohexadione calcium that result in chronic residential exposure to prohexadione calcium.  In addition, there is potential for chronic dietary exposure to prohexadione calcium in drinking water.  After calculating DWLOCs and comparing them to the EECs for surface and ground water, EPA does not expect the aggregate exposure to exceed 100% of the cPAD, as shown in the following Table 3: **Table 3.—Aggregate Risk Assessment for Chronic (Non- Cancer) Exposure to prohexadione calcium**
Population Subgroup
cPAD mg/kg/day
%cPAD (Food)
Surface Water EEC (ppb)
Ground Water EEC (ppb)
Chronic DWLOC (ppb)U.S. Population
0.80
< 1
7.73
0.001
28,000All Infants (< 1 year old)
0.80
2
7.73
0.001
8,000Children 1-6 years old
0.80
2
7.73
0.001
8,000Females 13-50 years old
0.80
< 1
7.73
0.001
24,000
 3. 
                    *Short-term risk*.  Short-term aggregate exposure takes into account residential exposure plus chronic exposure to food and water (considered to be a background exposure level).  Prohexadione calcium is not registered for use on any sites that would result in residential exposure.  Therefore, the aggregate risk is the sum of the risk from food and water, which do not exceed the Agency's level of concern. 4. 
                    *Intermediate-term risk*.  Intermediate-term aggregate exposure takes into account residential exposure plus chronic exposure to food and water (considered to be a background exposure level).  Prohexadione calcium is not registered for use on any sites that would result in residential exposure. Therefore, the aggregate risk is the sum of the risk from food and water, which do not exceed the Agency's level of concern.
                    ( print page 29711) 5. 
                    *Aggregate cancer risk for U.S. population*.  Prohexadione calcium is classified as not likely to be carcinogenic to humans by all routes of exposure based upon lack of evidence of carcinogenicity in rats and mice, therefore, no cancer risk is expected. 6. 
                    *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, and to infants and children from aggregate exposure to prohexadione calcium residues. IV. Other Considerations A. Analytical Enforcement Methodology Adequate enforcement methodology (gas chromatography and mass selective detector) is available to enforce the tolerance expression. The method may be requested from: Calvin Furlow, PRRIB, IRSD (7502C), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW, Washington, DC 20460; telephone number: (703) 305-5229; e-mail address: furlow.calvin@epa.gov. B. International Residue Limits There is neither a Codex proposal, nor Canadian or Mexican limits for residues of prohexadione calcium in/on plant or livestock commodities. C. Conditions A 21-day dermal toxicity study in rabbits (OPPTS 870.3200) is required. V. Conclusion Therefore, the tolerance is established for residues of  prohexadione calcium, calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate in or on grass forage at 0.10 ppm, grass hay at  0.10 ppm, grass straw at 1.2 ppm and grass seed screenings at 3.5 ppm. VI. Objections and Hearing Requests Under section 408(g) of the FFDCA, as amended by the FQPA, any person may file an objection to any aspect of this regulation and may also request a hearing on those objections.  The EPA procedural regulations which govern the submission of objections and requests for hearings appear in 40 CFR part 178.  Although the procedures in those regulations require some modification to reflect the amendments made to the FFDCA by the FQPA of 1996, EPA will continue to use those procedures, with appropriate adjustments, until the necessary modifications can be made.  The new section 408(g) provides essentially the same process for persons to “object” to a regulation for an exemption from the requirement of a tolerance issued by EPA under new section 408(d), as was provided in the old FFDCA sections 408 and 409. However, the period for filing objections is now 60 days, rather than 30 days. A. What Do I Need to Do to File an Objection or Request a Hearing? You must file your objection or request a hearing on this regulation in accordance with the instructions provided in this unit and in 40 CFR part 178.  To ensure proper receipt by EPA, you must identify docket control number OPP-301128 in the subject line on the first page of your submission.  All requests must be in writing, and must be mailed or delivered to the Hearing Clerk on or before July 31, 2001. 1. 
                    *Filing the request*.  Your objection must specify the specific provisions in the regulation that you object to, and the grounds for the objections (40 CFR 178.25).  If a hearing is requested, the objections must include a statement of the factual issues(s) on which a hearing is requested, the requestor's contentions on such issues, and a summary of any evidence relied upon by the objector (40 CFR 178.27).  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. Mail your written request to: Office of the Hearing Clerk (1900), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.  You may also deliver your request to the Office of the Hearing Clerk in Rm. C400, Waterside Mall, 401 M St., SW., Washington, DC 20460.  The Office of the Hearing Clerk is open from 8 a.m. to 4 p.m., Monday through Friday, excluding legal holidays.  The telephone number for the Office of the Hearing Clerk is (202) 260-4865. 2. 
                    *Tolerance fee payment*.  If you file an objection or request a hearing, you must also pay the fee prescribed by 40 CFR 180.33(i) or request a waiver of that fee pursuant to 40 CFR 180.33(m).  You must mail the fee to: EPA Headquarters Accounting Operations Branch, Office of Pesticide Programs, P.O. Box 360277M, Pittsburgh, PA 15251.  Please identify the fee submission by labeling it “Tolerance Petition Fees.” EPA is authorized to waive any fee requirement “when in the judgement of the Administrator such a waiver or refund is equitable and not contrary to the purpose of this subsection.”  For additional information regarding the waiver of these fees, you may contact James Tompkins by phone at (703) 305-5697, by e-mail at tompkins.jim@epa.gov, or by mailing a request for information to Mr. Tompkins at Registration Division (7505C), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460. If you would like to request a waiver of the tolerance objection fees, you must mail your request for such a waiver to: James Hollins, Information Resources and Services Division (7502C), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460. 3. 
                    *Copies for the Docket*.  In addition to filing an objection or hearing request with the Hearing Clerk as described in Unit VI.A., you should also send a copy of your request to the PIRIB for its inclusion in the official record that is described in Unit I.B.2.  Mail your copies, identified by docket control number OPP-301128, to: Public Information and Records Integrity Branch, Information Resources and Services Division (7502C), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.  In person or by courier, bring a copy to the location of the PIRIB described in Unit I.B.2.  You may also send an electronic copy of your request via e-mail to: opp-docket@epa.gov.  Please use an ASCII file format and avoid the use of special characters and any form of encryption. Copies of electronic objections and hearing requests will also be accepted on disks in WordPerfect 6.1/8.0 or ASCII file format.  Do not include any CBI in your electronic copy.  You may also submit an electronic copy of your request at many Federal Depository Libraries. B. When Will the Agency Grant a Request for a Hearing? A request for a hearing will be granted if the Administrator determines that the material submitted shows the following: There is a 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(s) in the manner sought by the requestor would be adequate to justify the action requested (40 CFR 178.32).
                    ( print page 29712) VII.  Regulatory Assessment Requirements This final rule establishes a tolerance 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) (Public Law 104-4).  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); or  OMB review or any Agency action under Executive Order 13045, entitled 
                    *Protection of Children from Environmental Health Risks and Safety Risks*
                     (62 FR 19885, April 23, 1997).  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 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272 note).  Since tolerances and exemptions that are established on the basis of a petition under FFDCA section 408(d), such as the tolerance 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.  In addition, the Agency has determined that this action will not have a substantial direct effect on States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government, as specified in Executive Order 13132, entitled 
                    *Federalism*
                    (64 FR 43255, August 10, 1999).  Executive Order 13132 requires EPA to develop an accountable process to ensure “meaningful and timely input by State and local officials in the development of regulatory policies that have federalism implications.”  “Policies that have federalism implications” is defined in the Executive Order to include regulations that have “substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.”  This final rule directly regulates growers, food processors, food handlers and food retailers, not States.  This action does not alter the relationships or distribution of power and responsibilities established by Congress in the preemption provisions of FFDCA section 408(n)(4).  For these same reasons, the Agency has determined that this rule does not have any tribal implications as described in Executive Order 13175, entitled Consultation and Coordination with Indian Tribal Governments (65 FR 67249, November 6, 2000).  Executive Order 13175, requires EPA to develop an accountable process to ensure meaningful and timely input by tribal officials in the development of regulatory policies that have tribal implications.  Policies that have tribal implications is defined in the Executive Order to include regulations that have substantial direct effects on one or more Indian Tribes, on the relationship between the Federal government and the Indian tribes, or on the distribution of power and responsibilities between the Federal government and Indian tribes.  This rule will not have substantial direct effects on tribal governments, on the relationship between the Federal government and Indian tribes, as specified in Executive Order 13175.  Thus, Executive Order 13175 does not apply to this rule. VIII.  Submission to Congress and the Comptroller General The Congressional Review Act, 5 U.S.C. 801 
                    *et seq.*, as added by the Small Business Regulatory Enforcement Fairness Act of 1996, generally provides that before a rule may take effect, the agency promulgating the rule must submit a rule report, which includes a copy of the rule, 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 16, 2001. 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. 321(q), 346(a) and 371. 2.Section 180.547 is amended by alphabetically adding commodities to the table in paragraph (a) to read as follows: § 180.547
  (a) * * * Commodity
Parts per million*   *   *   *   *Grass, forage1
0.10 ppmGrass, hay1
0.10 ppmGrass, seed screenings1
3.5 ppmGrass, straw1
1.2 ppm*   *   *   *   *1
                                Registration is limited to grasses grown for seed.


[FR Doc. 01-13774 Filed 5-31-01; 8:45 am] BILLING CODE 6560-50-S