[Federal Register Volume 62, Number 48 (Wednesday, March 12, 1997)]
[Notices]
[Pages 11437-11441]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-6015]


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ENVIRONMENTAL PROTECTION AGENCY
[PF-712; FRL-5587-7]


The Cryolite Task Force; Pesticide Tolerance Petition Filing

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of filing.

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SUMMARY: This notice announces the filing of a pesticide petition 
proposing regulations establishing tolerances for residues of the 
insecticidal fluorine compounds cryolite and/or synthetic cryolite 
(sodium aluminum fluoride or sodium aluminofluoride) in or on potatoes 
and in processed potato waste. This notice includes a summary of the 
petition that was prepared by the petitioner, The Cryolite Task Force.

DATES: Comments, identified by the docket control number [PF-712] must 
be received on or before April 11, 1997.

ADDRESSES: By mail, submit written comments to: Public Response and 
Program Resources Branch, Field Operations Division (7506C), Office of 
Pesticide Programs, Environmental Protection Agency, 401 M St., SW., 
Washington, DC 20460. In person, bring comments to: Rm. 1132 CM #2, 
1921 Jefferson Davis Highway, Arlington, VA 22202.
    Comments and data may also be submitted electronically by sending 
electronic mail (e-mail) to: [email protected]. Electronic 
comments must be submitted either in ASCII format (avoiding the use of 
special characters and any form of encryption) or in WordPerfect in 5.1 
file format. All comments and data in electronic form must be 
identified by the docket control number [PF-712]. Electronic comments 
on this notice may be filed online at many Federal Depository 
Libraries. The official record for this rulemaking, as well as the 
public version described above, will be kept in paper form. Additional 
information on electronic submissions can be found in Unit II. of this 
document.
    Information submitted as a comment concerning this notice may be 
claimed confidential by marking any part or all of that information as 
``Confidential Business Information'' (CBI). Information so marked will 
not be

[[Page 11438]]

disclosed except in accordance with procedures set forth in 40 CFR part 
2. No CBI should be submitted through e-mail. A copy of the comment 
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.

FOR FURTHER INFORMATION CONTACT: William Jacobs, Acting, Product 
Manager 14, Registration Division, Office of Pesticide Programs, 
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460. 
Office location, telephone number, and e-mail address: Rm. 219, CM #2, 
1921 Jefferson Davis Highway, Arlington, VA 22202. (703) 305-6600; e-
mail: [email protected].

SUPPLEMENTARY INFORMATION: EPA has received a pesticide petition from 
The Cryolite Task Force c/o Gowan, P.O. Box 5568, Yuma, AZ 85366. The 
petition proposes, pursuant to section 408 of the Federal Food, Drug, 
and Cosmetic Act (FFDCA), 21 U.S.C. 346a, to amend 40 CFR 180.145 to 
renew the regulations that established tolerances for the insecticidal 
fluorine compounds cryolite and/or synthetic cryolite in or on potatoes 
at 2.0 parts per million (ppm) and processed potato waste at 22 ppm.
    EPA has determined that the petition contains data or information 
regarding the elements set forth in section 408(d)(2); however, EPA has 
not fully evaluated the sufficiency of the submitted data at this time 
or whether the data supports granting of the petition. Additional data 
may be needed before EPA rules on the petition.
    As required by section 408(d) of the FFDCA, as recently amended by 
the Food Quality Protection Act (FQPA) (Pub. L. 104-170), The Cryolite 
Task Force included in the petition a summary of the petition and 
authorization for the summary to be published in the Federal Register 
in a notice of receipt of the petition. The summary represents the 
views of The Cryolite Task Force; EPA is in the process of evaluating 
the petition. As required by section 408(d)(3), EPA is including the 
summary as a part of this notice of filing. EPA may have made minor 
edits to the summary for purposes of clarity.

I. The Cryolite Task Force's Petition Summary

    This petition is submitted by the Cryolite Task Force (Consortium 
No. 62569), under section 408 of the FFDCA, as most recently amended by 
the FQPA.
    This submission amends petitions PP 9F3739 and FAP 1H5604 by 
providing the additional information specified by the FQPA. A permanent 
tolerance is proposed for residues of the insecticide sodium 
aluminofluoride (cryolite and/or synthetic cryolite) in or on the raw 
agricultural commodities (RAC) potatoes, as provided by the new FFDCA 
section 408. In addition, the petitioner proposes that EPA establish a 
permanent tolerance for residues of cryolite in processed potato waste, 
as provided under the new FFDCA section 408.
    Time-limited tolerances for residues of sodium aluminofluoride 
(cryolite and/or synthetic cryolite) in/on potatoes and processed 
potato waste were initially granted on May 5, 1993. These tolerances 
expired on May 6, 1996. A time limitation was required initially for 
these regulations because a chronic dog feeding study and a two-
generation rat reproduction study were outstanding. These two studies 
were submitted and were found acceptable in reviews dated April 13, 
1994 (chronic dog) and February 24, 1995 (rat reproduction). In the 
Federal Register of May 8, 1996 (61 FR 20781) (FRL-5362-6), EPA 
proposed establishing permanent tolerances of 2 ppm and 22 ppm for 
residues of cryolite in/on potatoes and processed potato waste, 
respectively. A 30-day comment period was specified by the Agency for 
these proposed regulations. However, prior to publication of final 
regulations, the FQPA specified additional requirements for tolerance 
petitions. This submission amends PP 9F3739 and FAP 1H5604 by providing 
the additional information specified.

A. Residue Data

    1. Name, identity, and composition of the residue. Cryolite (sodium 
aluminofluoride, sodium hexafluoroaluminate or sodium aluminum 
fluoride) is a fluorine-containing insecticide which is found in 
naturally occurring mineral deposits and also is produced 
synthetically.
    Empirical Formula: Na3AlF6
    Molecular Weight: 209.97
    CAS Registry No.: 15096-52-3
    OPP Chemical Code: 075101
    A Reregistration Eligibility Decision (RED) was issued for cryolite 
in August 1996. As documented in the May 8, 1996 Federal Register and 
reiterated in the RED, the Agency has determined that plant residues 
are inorganic surface residues of cryolite, measured as total fluoride; 
and that the residue of concern in animals also is total fluoride.
    Provisions in the FQPA which are relevant to degradates or 
metabolites of pesticide chemical residues are not applicable to 
elemental fluorine.
    2. Magnitude of the residue in plants. As documented in the May 8, 
1996 Federal Register and reiterated in the RED, the Agency has 
concluded that complete and acceptable crop residue data are available 
to support the proposed tolerance of 2 ppm in or on potatoes.
    Data previously reviewed by EPA show background levels of fluoride 
in untreated potatoes ranging from 0.14 ppm to 0.31 ppm. Levels of 
fluoride found in treated potatoes ranged from 0.18 ppm to 0.94 ppm.
    3. Magnitude of the residue in processed food/feed. As documented 
in the May 8, 1996 Federal Register and reiterated in the RED, EPA has 
concluded that an acceptable potato processing study supports the 
proposed tolerance of 22 ppm in or on processed potato waste. This 
study indicates that cryolite residues concentrated 11x in potato 
peels/potato waste processed from potatoes treated at a 6.7x 
exaggerated rate. Residues did not concentrate in potato chips, flakes, 
or granules.
    4. Directions for use. Labeling has been approved for foliar 
application to potatoes at up to 11.5 lbs. active ingredient (a.i.) per 
acre, with a maximum seasonal application of 92 lbs. a.i. per acre.
    5. Analytical method. EPA concluded in the May 8, 1996 Federal 
Register and reiterated in the cryolite RED that adequate methodology 
is available for data collection and tolerance enforcement. Methods for 
both plant residues and animal tissues have undergone successful Agency 
validation and will be published in PAM, Vol. II. Using these methods, 
total fluoride is determined using a pH/ion meter with a fluoride-
specific electrode. The limit of quantitation is 0.05 ppm. The residue 
analytical method does not distinguish between naturally occurring 
fluoride and fluoride resulting from agricultural use of cryolite. 
Current FDA multi-residue screening protocols are not appropriate for 
inorganic fluoride residues.
    6. Practical methods for removing residues. Plant residues are 
inorganic surface residues of cryolite. Data previously submitted in 
FAP 1H5604 show that washing and peeling are effective methods of 
removing these residues.
    7. Plant metabolism. EPA concluded in the May 8, 1996 Federal 
Register and reiterated in the cryolite RED that the qualitative nature 
of the residue in plants is understood and that plant residues are 
inorganic surface residues

[[Page 11439]]

of cryolite which are measured as fluoride.
    8. Animal metabolism. EPA concluded in the May 8, 1996 Federal 
Register and reiterated in the cryolite RED that cryolite metabolism in 
animals manifests itself as free fluoride, that the qualitative nature 
of the residue is understood and that total fluoride is the residue of 
concern.
    9. Magnitude of the residue in meat, milk, poultry and eggs. EPA 
concluded in the May 8, 1996 Federal Register and reiterated in the 
cryolite RED that there is no reasonable expectation of finite fluoride 
residues in ruminant or poultry tissues as a result of livestock 
ingestion of cryolite.

B. Toxicological Data

    The cryolite RED concluded that the toxicological data base was 
adequate for a reregistration eligibility decision for numerous crop 
uses, including potatoes. No additional toxicology requirements were 
specified in the RED. The cryolite residue of toxicological concern is 
fluoride; and health effects identified for fluoride in humans and 
animals are skeletal and dental fluorosis. Dental fluorosis (mottling 
of tooth enamel) is not considered to be an adverse effect.
    Further, the Agency has determined that although fluoride 
accumulation is demonstrated in a number of studies, the accumulation 
itself is not considered an adverse effect.
    1. Acute toxicity. A rat acute oral toxicity study (MRID 00138096) 
showed an LD50 greater than 5,000 milligrams/kilograms (mg/kg). A 
rabbit acute dermal toxicity study (MRID 00128107) demonstrated an 
LD50 of 2,100 mg/kg. An LC50 > 2.06 mg/L and < 5.03 mg/L was 
seen in an acute inhalation study with rats (MRID 00128107). Technical 
cryolite is a moderate eye irritant in rabbits (MRID 00128106). 
Cryolite is not a skin irritant to rabbits (MRID 00128106) and is not a 
dermal sensitizer to guinea pigs (MRID 00138097).
    2. Subchronic toxicity. Cryolite was tested in a 28-day range-
finding feeding study in rats (MRID 00128109) at dose levels of 0, 250, 
500, 1,000, 2,000, 4,000, 10,000, 25,000, and 50,000 ppm in the diet 
(representing approximately 0, 25, 50, 100, 200, 400, 1,000, 2,500 and 
5,000 mg/kg/day). The only compound related effect seen in this study 
was a change in coloration and physical property of the teeth. A no 
observed effect level (NOEL) was not determined in this study. The 
lowest observed effect level (LOEL) is 250 ppm (25 mg/kg/day) based on 
dental fluorosis.
    In a 90-day rat feeding study (MRID 00158000), cryolite was tested 
at dose levels of 0, 50, 5,000, and 50,000 ppm (corresponding to 0, 
3.8, 399.2, and 4,172.3 mg/kg/day in males and 0, 4.5, 455.9, and 
4,758.1 mg/kg/day in females). The NOEL was 50 ppm (3.8 mg/kg/day) for 
effects other than fluoride accumulation. The LOEL was 5,000 ppm (399.2 
mg/kg/day) based on lesions observed in the stomach. Fluoride 
accumulated at all dose levels in this study. Cryolite was tested in a 
90-day dog feeding study (MRID 00157999) at dose levels of 0, 500, 
10,000, and 50,000 ppm (corresponding to 0, 17,368, and 1,692 mg/kg/
day). The NOEL was 10,000 ppm (368 mg/kg/day). The LOEL was 50,000 ppm 
(1,692 mg/kg/day) for effects other than fluoride accumulation. 
Fluoride accumulation occurred at all dose levels.
    A 21-day subchronic dermal toxicity study in rabbits (MRID 
41224801) is considered invalid because it is likely that cryolite was 
ingested by the test animals during the study. For this reason, the 
systemic dermal NOEL and LOEL could not be determined from this study. 
EPA noted in the RED that an additional subchronic dermal study is not 
necessary, because based on its chemical/physical properties, cryolite 
would not be absorbed through the skin to any appreciable extent.
    3. Genotoxicity. Cryolite was negative in an Ames reverse mutation 
test (MRID 41838401) using Salmonella typhimurium with and without 
activation at dose levels of 167, 500, 1,670, 5,000, 7,500, and 10,000 
g/plate. Cryolite was tested in an in vitro chromosome 
aberration assay (MRID 41838402) using human lymphocytes at 100, 500, 
and 1,000 g/ml, with and without activation. The results were 
negative. Cryolite also was negative in an unscheduled DNA synthesis 
study (MRID 41838403) with rat hepatocytes at dose levels up to and 
including 50 g/ml.
    4. Chronic toxicity. The Agency concluded in the May 8, 1996 
Federal Register and reiterated in the cryolite RED that the available 
information does not support the regulation of cryolite insecticides as 
carcinogens. The Agency has classified cryolite as a Group D chemical 
(not classifiable as to human carcinogenicity. Further, EPA has noted 
that fluoride has been the subject of a comprehensive review by the 
National Research Council (National Academy of Sciences Subcommittee of 
Health Effects of Ingested Fluoride) who concluded that ``. . .the 
available laboratory data are insufficient to demonstrate a 
carcinogenic effect of fluoride in animals'' and that ``. . .the weight 
of evidence from more that 50 epidemiological studies does not support 
the hypothesis of an association between fluoride exposure and 
increased cancer risk in humans.'' As stated in the May 8, 1996 Federal 
Register and reiterated in the cryolite RED, the Agency is in agreement 
with the conclusions reached by the National Academy of Science (NAS).
    The following specific chronic/oncogenicity studies are included in 
the cryolite toxicology data base:
    A 2-year bioassay in B6C3F1 mice (HED DOC No. 009682) was conducted 
by the National Toxicology Program (NTP) using sodium fluoride as the 
test material at dose levels of 0, 25, 100, and 175 ppm, in water, 
representing 0, 2.4, 9.6, and 16.7 mg/kg/day in males and 0, 2.8, 11.3, 
and 18.8 mg/kg/day in females. The NOEL was less than 25 ppm (2.4 mg/
kg/day). The LOEL was 25 ppm (2.4 mg/kg/day) based on attrition of the 
teeth in males, discoloration and mottling of the teeth in males and 
females, and increased bone fluoride in both sexes. NTP considered that 
there was no evidence of carcinogenic activity in male and female mice.
    A 2-year bioassay in F344/N rats (HED DOC No. 009682) also was 
conducted by the NTP using sodium fluoride as the test material at dose 
levels of 0, 25, 47, 100, and 175 ppm, in water, representing 0, 1.3, 
5.2, and 8.6 mg/kg/day in males and 0, 1.3, 5.5, and 9.5 mg/kg/day in 
females. Osteosarcoma of the bone was observed only in 1 male of 50 (1/
50) in the 100 ppm group and in 3 of 80 (3/80) males in the 175 ppm 
group. The NOEL was less than 25 ppm (1.3 mg/kg/day). The LOEL was 25 
ppm (1.3 mg/kg/day) based on mottling of teeth, dentine incisor 
dysplasia, increased serum, urine and bone fluoride levels in males and 
females and incisor odontoblast and incisor ameloblast degeneration in 
males. NTP considered that there was ``equivocal evidence'' of 
carcinogenic activity in male rats in this study and ``no evidence'' of 
carcinogenic activity in female rats.
    EPA concluded in the May 8, 1996 Federal Register and reiterated in 
the cryolite RED that the NTP studies utilizing sodium fluoride in lieu 
of cryolite satisfy the guideline study requirements for both the 
rodent chronic feeding study and the rat carcinogenicity study. 
Fluoride has been identified as the residue of toxicological concern in 
cryolite and synthetic cryolite and these compounds act as free 
fluoride. It should be noted that the NTP studies, which utilized 
freely soluble NaF represent a worst-case toxicological scenario on a 
ppm basis compared to what would be expected with cryolite per se, from 
which fluoride ion dissociation is much more limited.

[[Page 11440]]

    A 1-year chronic dog feeding study (MRID 42575101) was conducted 
with cryolite at dose levels of 0, 3,000, 10,000, and 30,000 ppm, 
representing 0, 95, 366, and 1,137 mg/kg/day in males and 0, 105, 387, 
and 1,139 mg/kg/day in females (in terms of fluoride, the doses are 0, 
51, 198, and 614 mg F/kg/day for males and 0, 57, 209, and 615 mg F/kg/
day for females). The NOEL was less than 3,000 ppm (95 mg/kg/day in 
males and 105 mg/kg/day in females). The LOEL was 3,000 ppm based on 
increases in emesis, nucleated cells in males, renal lesions, and a 
decrease in urine-specific gravity in females.
    5. Reproductive toxicity. A two-generation rat reproduction study 
(MRID 43387501) was conducted with cryolite at dietary dose levels of 
0, 200, 600, and 1,800 ppm (representing 0, 14, 42, and 128 mg/kg/day 
for males and 0, 16, 49, and 149 mg/kg/day for females, respectively, 
during premating). The systemic toxicity NOEL was not determined. The 
LOEL for systemic toxicity was 200 ppm (15 mg/kg/day) based on dental 
fluorosis. The NOEL and LOEL for reproductive toxicity were 600 and 
1,800 ppm, respectively (46 and 138 mg/kg/day) based on decreased pup 
body weights.
    The National Research Council (NRC) has reviewed the potential for 
reproductive effects from fluoride per se. In the report Health Effects 
of Ingested Fluoride, the NRC concluded that:

    There have been reports of adverse effects on reproductive 
outcomes associated with high levels of fluoride in many animal 
species. In most of the studies, however, the fluoride 
concentrations associated with adverse effects were far higher than 
those encountered in drinking water. The apparent threshold 
concentration for inducing reproductive effects was 100 mg/L in 
mice, rats, foxes and cattle; 100-200 mg/L in minks, owls and 
kestrels; and over 500 mg/L in hens. Based on these findings, the 
subcommittee concludes that the fluoride concentrations associated 
with adverse reproductive effects in animals are far higher than 
those to which human populations are exposed. Consequently, 
ingestion of fluoride at current concentrations should have no 
adverse effects on human reproduction.

    6. Developmental toxicity. A developmental toxicity study was 
performed with cryolite in rats (MRID 00128112) at dose levels of 0, 
750, 1,500, and 3,000 mg/kg/day (gavage). The NOEL for both 
developmental and maternal toxicity was 3,000 mg/kg/day. At this dose 
level, the only observation was whitening of the teeth of dams. A 
developmental toxicity study was conducted in female mice (MRID 
42297902) with cryolite at dose levels of 0, 30, 100, and 300 mg/kg/day 
(gavage). The NOEL for maternal toxicity was 30 mg/kg/day and the LOEL 
was 100 mg/kg/day based on a single mortality in this group. Fetuses at 
300 mg/kg/day exhibited bent ribs and bent limb bones. The NOEL for 
developmental toxicity was 100 mg/kg/day. The LOEL was 300 mg/kg/day 
based on an increase in bent ribs and bent limbs. A range-finding 
developmental toxicity study in female rabbits (MRID 42297901) tested 
cryolite at dose levels of 0, 10, 30, 100, 300, and 1,000 mg/kg/day 
(gavage). The NOEL for maternal toxicity was determined to be 10 mg/kg/
day and the LOEL was 30 mg/kg/day based on an increased incidence of 
soft stool and dark colored feces and decreased defecation and 
urination. The NOEL for developmental toxicity was 30 mg/kg/day. The 
developmental LOEL could not be assessed due to excessive maternal 
toxicity at dose levels of > 30 mg/kg/day.
    7. Metabolism/metabolite toxicity. As noted in the May 8, 1996 
Federal Register and reiterated in the RED, cryolite behaves 
toxicologically as free fluoride. That is, dissociation produces free 
fluoride ions which are assimilated into bone. There are numerous 
references in the open literature concerning the metabolism of cryolite 
and other fluoride salts. The National Research Council concluded in 
their 1993 comprehensive report entitled ``Health Effects of Ingested 
Fluoride'' that fluoride is readily absorbed by the gut and rapidly 
becomes associated with teeth and bones. The remaining fluoride is 
eliminated almost exclusively by the kidneys with the rate of renal 
clearance related directly to urinary pH.
    8. Endocrine effects. The two-generation rat reproduction study, 
the rat, rabbit and mouse developmental studies and the dog chronic 
studies summarized above did not demonstrate any effects with cryolite 
that are similar to those produced by naturally occurring estrogens, or 
other endocrine effects. No endocrine effects were determined in the 
rat and mouse NTP studies.
    In addition, it should be noted that national and international 
regulatory organizations (U.S. EPA Office of Water, U.S. DHHS, the 
Canadian Government, and the World Health Organization) have assessed 
potential health risks from exposure to fluoride. EPA has concluded 
that the endpoints and estimated effect levels documented by these 
organizations are similar and that the health effects of fluoride in 
animals and humans include dental and skeletal fluorosis. Endocrine 
effects have not been recognized as toxicological endpoints for 
fluoride by any worldwide regulatory authority.

C. Aggregate Exposure

    1. Dietary exposure-food. As noted in the May 8, 1996 Federal 
Register and reiterated in the RED, the Agency has estimated dietary 
exposure to cryolite using reassessed tolerances for all crops 
(including the proposed tolerances for potatoes) and percent of crop 
treated assumptions. In the RED, EPA estimated dietary exposure to 
cryolite from all crops to be approximately 0.020 mg/kg/day for the 
U.S. population, 0.024 mg/kg/day for children 1-6, 0.015 mg/kg/day for 
children 7-12, and 0.028 mg/kg/day for nursing females 13+ years. For 
the highest exposed subgroup (females 20 years old and over), the 
Agency estimated exposure of 0.038 mg/kg/day (61 FR 20781). The Agency 
estimated dietary exposure resulting from the specific use of cryolite 
on potatoes to be approximately 0.00016 mg/kg/day. The Task Force 
believes that these exposure estimates in fact overstate actual dietary 
exposure since cryolite tolerance levels, rather than residues actually 
present at the consumer level were used by EPA in the exposure 
assessments.
    2. Dietary exposure- drinking water. In the Environmental Fate 
Assessment conducted for the RED, the Agency concluded that the use of 
cryolite should have negligible impacts on fluoride levels in ground 
and surface water. For this reason, the contribution of cryolite to 
potential exposure to fluoride from drinking water need not be 
considered in the aggregate risk assessment.
    However, fluoride is intentionally supplemented to drinking water 
for prevention of dental caries and may also be present at natural 
background levels. The U.S. Public Health Service recommends an optimal 
fluoride concentration of 0.7 to 1.2 mg/L to prevent dental caries and 
minimize dental fluorosis.
    Fluoride levels in public drinking water are regulated under the 
Safe Drinking Water Act. A Maximum Concentration Limit (MCL) of 4.0 mg/
L (0.114 mg/kg/day) has been established. EPA has previously estimated 
that levels of fluoride in/on food from the agricultural use of 
cryolite plus fluoride levels in U.S. drinking water supplies results 
in a daily dietary intake of fluoride of approximately 0.095 mg/kg/day. 
This is substantially less than the Maximum Concentration Limit (MCL) 
of 4.0 mg/L (0.144 mg/kg/day), a level which provides no known or 
anticipated adverse health effect as determined by the Surgeon General.
    As noted in the May 8, 1996 Federal Register and reiterated in the 
RED, the Agency has concurred with the findings

[[Page 11441]]

of the Surgeon General that adverse health effects have not been found 
in the U. S. population below 8 mg F/L (0.23 mg/kg/day).
    3. Non-dietary exposure. Cryolite is used almost exclusively as an 
agricultural crop protection insecticide. Conceivably, cryolite also 
could be used in outdoor homeowner/residential sites for insect control 
in ornamentals and shade trees. Cryolite is not registered for either 
lawn or crack and crevice treatments. EPA concluded in the RED that a 
post-application exposure assessment for cryolite (including both 
occupational and residential exposure) was not appropriate since no 
toxicological endpoints relevant to non-dietary exposure have been 
identified for cryolite. The Task Force concludes that non-dietary 
exposure represents a negligible component of potential aggregate 
exposure to cryolite and need not be considered in the aggregate risk 
assessment.

D. Cumulative Effects

    The residue of toxicological concern in cryolite is fluoride. 
Although fluoride supplements in drinking water are not considered to 
be pesticidal substances, the dietary contribution of drinking water to 
overall fluoride exposure has been discussed elsewhere in this summary. 
Current tolerances for insecticidal fluorine-containing compounds are 
limited to cryolite and synthetic cryolite. For this reason, 
consideration of potential cumulative effects of residues from 
pesticidal substances other than sodium aluminofluoride with a common 
mechanism of toxicity are not applicable.

E. Safety Determination

    1. U.S. population. As discussed above, non-dietary exposure to 
cryolite is negligible. For dietary exposure, EPA has concluded that 
rather than establishing a traditional Reference Dose (RfD), a weight-
of-the-evidence risk assessment is a more appropriate approach for 
cryolite. The toxicological endpoint of concern for dietary exposure to 
cryolite is skeletal fluorosis. EPA has approximated that total dietary 
fluoride levels in food plus drinking water is 0.095 mg/kg/day. Of this 
total exposure, the dietary (food) contribution is about 0.020 mg/kg/
day for the U.S. population, and 0.038 mg/kg/day for the highest 
exposed subgroup (females 20 years old and over). The proposed potato 
tolerances have been estimated by EPA to contribute approximately 
0.00016 mg/kg/day to total dietary exposure. These exposure estimates 
likely overstate actual dietary exposure, since marketbasket residue 
levels for cryolite have not been considered. As noted above, the 
Agency has concurred with the findings of the Surgeon General that 
adverse health effects (skeletal fluorosis) have not been found in the 
U.S. population below 8 mg F/L (0.23 mg/kg/day).
    2. Infants and children. EPA has concluded previously that in rats, 
the developmental NOEL for cryolite is 3,000 mg/kg/day (1,584 mg/kg/day 
F), that in mice, the developmental NOEL is 100 mg/kg/day (52.8 mg/kg/
day F), and that in rabbits, the developmental NOEL is 30 mg/kg/day 
(15.8 mg/kg/day F). The NOEL for reproductive toxicity of cryolite 
determined in a 2-generation rat reproduction study was determined by 
the Agency to be 46 mg/kg/day (24.3 mg/kg/day F).
     These data show clearly that no additional margin of safety is 
required for exposure of infants and children to cryolite. The 
developmental NOEL ranges from more than 166x (rabbit) to more than 
16,000x (rat) for the maximum combined exposure of infants and children 
to residues of fluoride from all agricultural uses of cryolite plus 
drinking water. The reproductive NOEL is about 256x greater than 
maximum combined exposure of infants and children to residues of 
fluoride.

F. International Tolerances

    No Codex, EC or other international tolerances are in effect for 
cryolite; thus, potential dietary exposure to fluoride from the 
agricultural use of cryolite on crops would not include imported 
foodstuffs.

II. Public Record

    A record has been established for this notice under docket control 
number [PF-712] (including comments and data submitted electronically 
as described below). A public version of the 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 1132 of the Public Response and Resources 
Branch, Field Operations Division (7506C), Office of Pesticide 
Programs, Environmental Protection Agency, Crystal Mall #2, 1921 
Jefferson Davis Highway, Arlington, VA.
    Electronic comments can be sent directly to EPA at:
    [email protected]
    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 all comments 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 address in ``ADDRESSES'' at the 
beginning of this document.

List of Subjects

    Environmental protection, Administrative practice and procedure, 
Agricultural commodities, Pesticides and pests, Reporting and 
recordkeeping requirements.

    Dated: February 24, 1997.
Peter Caulkins,
Acting Director, Registration Division, Office of Pesticide Programs.
[FR Doc. 97-6015 Filed 3-11-97; 8:45 am]
BILLING CODE 6560-50-F