[Federal Register Volume 64, Number 110 (Wednesday, June 9, 1999)]
[Proposed Rules]
[Pages 30939-30949]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-14069]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 180, 185 and 186
[OPP-300865; FRL-6082-4]
RIN 2070-AB78
Phosphine; Pesticide Tolerances
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: Tolerances are being revised and consolidated for residues of
phosphine in or on certain agricultural commodities and animal feeds.
None of these proposed tolerances are new, although this change would
facilitate new application methods. The Agency is merely changing the
tolerance expression to eliminate references
[[Page 30940]]
concerning how the phosphine gas is generated.
DATES: Comments, identified by the docket control number [OPP-300865],
must be received on or before July 9, 1999.
ADDRESSES: By mail, submit written comments 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, deliver comments to:
Rm. 119, CM #2, 1921 Jefferson Davis Highway, Arlington, VA.
Comments and data may also be submitted electronically to: docket@epamail.epa.gov. Follow the instructions under Unit VI. of this
document. No Confidential Business Information (CBI) should be
submitted through e-mail.
Information submitted as a comment concerning this document 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 comment that
does not contain CBI must be submitted for inclusion in the public
record. Information not marked confidential will be included in the
public docket by EPA without prior notice. The public docket is
available for public inspection in Rm. 119 at the Virginia address
given above, from 8:30 a.m. to 4 p.m., Monday through Friday, excluding
legal holidays.
Interested persons are invited to submit comments on the proposed
regulation. Comments must bear a notation indicating the docket control
number [OPP-300865].
FOR FURTHER INFORMATION CONTACT: By mail: Dennis McNeilly, 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) 308-6742, e-mail:
McNeilly.dennis@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: In the Federal Register of December 23,
1998, (FRL-6053-6), EPA announced the availability of the
Reregistration Eligibility Decision (RED) for aluminum and magnesium
phosphide, which was signed on September 30, 1998. This document
discusses in detail the Agency's risk assessment for these two very
similar pesticides.
Current tolerances established for aluminum and magnesium phosphide
are expressed in terms of residues of the fumigant phosphine resulting
from the use of aluminum and/or magnesium phosphide, respectively. Both
of these chemicals have very similar use patterns, chemical properties
and both result in the same residue (hydrogen phosphide), both
qualitatively and quantitatively. In fact, due to the high reactivity
and volatility of these two compounds the detection of finite residues
is not expected and the residue data indicate non- detectable levels of
phosphine, when label directions concerning aeration for 48 hours
before entering into commerce are followed. The Agency has decided to
revise the current tolerance expressions because it does not matter
from a safety or practical standpoint, i.e. tolerance enforcement
purposes, whether residues of phosphine result from treatment with
aluminum phosphide or magnesium phosphide. In fact, having tolerances
expressed in this manner precludes treatment of the food and/or feed
commodities with phosphine gas delivered or generated via different
technology. Different application techniques involving direct
application of phosphine gas have the potential to reduce worker
exposure because fumigators would not need to enter the facility being
fumigated.
The aluminum and magnesium phosphide RED states that the tolerances
listed under 40 CFR 180.225 (a) and (b), 185.200, and 186.200 and
tolerances for magnesium phosphine listed under 40 CFR 180.375 (a) and
(b), 185.3800, and 186.3800 should be amended to consolidate all of
these tolerances in the Code of Federal Regulations. Following passage
of the Food Quality Protection Act (FQPA), tolerances for pesticide
residues in all types of food (raw or processed) are set under the same
provision of the law and EPA is including all such tolerances in part
180 of the Code of Federal Regulations. The Agency will list all
aluminum phosphide and magnesium phosphide tolerances under 40 CFR
180.225 and be subdivided into paragraphs (a)(1), (a)(2), (a)(3), and
(a)(4). Tolerances in the new paragraph (a)(1) concern residues
resulting in or on Raw Agricultural Commodities (RACs) from post-
harvest fumigation uses. Tolerances in paragraph (a)(2) concern
residues in or on RACs from preharvest treatment of pest burrows in
agricultural and non-crop land areas. The Agency notes that this use
involves control of vector borne disease, especially in the
southwestern United States. Paragraph (a)(3) concerns residues
resulting from fumigation of processed foods. Finally, paragraph (a)(4)
concerns residues resulting from fumigation of animal feeds. There are
no tolerances established, nor are there any uses registered, for the
direct treatment of any field crop or greenhouse-grown food commodity.
The Agency recently updated the list of raw agricultural and
processed commodities and foodstuffs derived from crops (Table 1 OPPTS
GLN 860.1000). As a result of changes to this table, commodity
definitions used in the CFR also need to be updated. For example,
instead of a tolerance expressed as corn, it should now specify corn,
grain or corn, forage, etc. Further, since the tolerances for phosphide
will be combined under a single tolerance expression for phosphine,
several commodities with tolerances currently listed under both
aluminum and magnesium phosphide would need only one tolerance. The
Agency notes that it is impossible for a laboratory to determine from
strictly analytical methods whether phosphine residues resulted from Al
or Mg phosphide application and for risk assessment it is irrelevant.
In addition, with the required 48-hour aeration period required on all
labels, finite residues are not expected in/on any food commodity.
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. 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
[[Page 30941]]
FR 62961, November 26, 1997)(FRL-5754-7).
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 phosphine
and to make a determination on aggregate exposure, consistent with
section 408(b)(2), for residues of phosphine in or on almond, nutmeat
at 0.1 parts per million (ppm); avocadoes at 0.01 ppm; bananas at 0.01
ppm; barley, grain at 0.1 ppm; Brazil nut at 0.1 ppm; Cabbage,Chinese
at 0.01 ppm; cacao, bean at 0.1 ppm; cashews at 0.1 ppm; citrus, citron
at 0.01 ppm; coffee, bean, green at 0.1 ppm; corn, field, grain at 0.1
ppm; corn, pop, grain at 0.1 ppm; cotton, seed, undelinted at 0.1 ppm;
date, dried at 0.1 ppm; eggplants at 0.01 ppm; endive (escarole) at
0.01 ppm; filbert at 0.1 ppm; grapefruit at 0.01 ppm; kumquats at 0.01
ppm; Legume vegetables succulent or dried group(excluding soybeans) at
0.0 1 ppm; lemons at 0.01 ppm; lettuce at 0.01 ppm; limes at 0.01 ppm;
mangoes at 0.01 ppm; millet, grain at 0.1 ppm; mushrooms at 0.01 ppm;
oats, grain at 0.1 ppm; oranges at 0.01 ppm; papayas at 0.01 ppm;
peanut, nutmeat at 0.1 ppm; pecans at 0.1 ppm; peppers at 0.01 ppm;
persimmons at 0.0 1 ppm; pistachios at 0.1 ppm; rice, grain at 0.1 ppm;
rye at 0.1 ppm; safflower seed at 0.1 ppm; salsify tops at 0.01 ppm;
sesame seed at 0.1 ppm; sorghum grain at 0.1 ppm; soybeans at 0.1 ppm;
sunflower, seed at 0.1 ppm; sweet potatoes at 0.01 ppm; tangelos at
0.01 ppm; tangerines at 0.01 ppm; tomatoes at 0.01 ppm; walnuts at 0.1
ppm; wheat, grain at 0.1 ppm; all Raw Agricultural Commodities (RAC)
resulting from preharvest treatment of pest burrows in agricultural and
non-cropland areas, 0.01 ppm; phosphine residues resulting from
fumigation of processed foods, 0.01 ppm; and phosphine residues
resulting from fumigation of animal feeds, 0.01 ppm.
EPA's assessment of the dietary 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.
The Agency does not normally use inhalation studies for oral
(dietary) risk assessments. However, inhalation studies were used for
these chemicals because: (1) Use of an inhalation ``dose'' provides a
conservative approach for oral risk assessments; (2) these studies
enable the Agency to quantify the dosage of phosphine exposed to
laboratory animals; (3) the Agency required inhalation studies (rather
than oral studies) for this chemical because exposure to this chemical
via inhalation is much more likely for those individuals who would have
occupational exposure.
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 phosphine are discussed below.
1. Acute toxicity. A rat acute inhalation study on phosphine
indicated an LC50 greater than 11 ppm, the highest dose
tested (HDT). This puts phosphine in Toxicity Category I, i.e., Highly
Toxic.
Given aluminum and magnesium phosphide's use patterns and chemical
characteristics, the other acute toxicity 81-series guideline studies
used to establish precautionary labeling were waived for these
chemicals as they would not change the Toxicity Category or effect
protective clothing requirements. The material of concern is phosphine
gas which is the material with pesticidal properties, when either
aluminum or magnesium phosphide are used.
2. Subchronic toxicity. In a 90 day rat inhalation study, Fischer
344 rats (10/sex/dose) were exposed to phosphine 6 hours/day, 5 days/
week for 13 weeks at levels of 0, 0.3, 1.0 or 3.0 ppm. Additional
groups (3-5/sex/group) were exposed at 0 or 10 ppm starting at week 8,
and 0 or 5 ppm starting at week 12. Recovery groups were included in
the study at each dose level and sacrificed after 4 weeks of post-
exposure observations. In the groups exposed at levels up to 3.0 ppm,
there was a transient decrease in body weight gain accompanied by
decreased food consumption. Red blood cell counts, hemoglobin
concentration, and hematocrit values were slightly decreased in males
exposed at 3.0 ppm (at 4 weeks only), but no effects were observed in
these males at 13 weeks or in females at either interval. No exposure-
related gross or histologic findings were observed at levels up to and
including 3.0 ppm. Exposure at 10 ppm for 3 days caused 40% mortality
in females but no mortality in males. Exposure at 10 ppm for 4 weeks
caused 80% death in females. Both males and females exposed at 10 ppm
had coagulative necrosis in the tubules of the kidneys and pulmonary
congestion was observed in the females that died. No histologic
findings related to dosing were apparent in the rats exposed for 2
weeks at 5 ppm; an increase in the BUN and alkaline phosphatase were
observed in males but not females exposed at 5 ppm. An LEL for
subchronic exposure (13 weeks) was not established in this study. The
no-observed adverse effect level (NOAEL) for 13 weeks was 3 ppm (HDT).
An LEL of 10 ppm for 4 weeks was based on lethality (4/5 deaths for
females) due to the sharp dose-response curve.
3. Chronic toxicity/carcinogenity. In a 2-year rat feeding study,
diets were treated with Phostoxin pellets at 48 and 90 gm/metric ton,
fumigated for 48 hours and 72 hours, mixed for 2 hours, and then
aerated for one hour. The feed was then stored frozen in small sealed
containers until used as laboratory rat feed. Sixteen separate batches
of feed were treated utilizing this methodology over the 2-year period.
Samples of diet were taken to determine phosphine at the time the feed
was removed from the freezer. Phosphine levels ranged from 0.2 to 7.5
ppm and averaged approximately 1 ppm. The amounts of phosphine that
remained in the feed offered to the rats as food was not measured (but
would be expected to be less because of dissipation). Therefore, the
actual dosages in this study are unknown. Two groups of 60 rats each
(30 males and 30 females) were used, one as treatment group and other
as controls. The rats were observed for the effects on growth, food
consumption, survival, morbidity, hematology, blood chemistry and gross
and microscopic pathology. No differences were seen between the
controls and the treated animals for any toxicity parameter. No
increased oncogenicity resulted from fumigation residues. The study was
not considered guideline since toxicity, secondary to phosphine
residues, is not possible when aeration is adequate. However, the study
shows that toxic levels of residues were not achieved even with the
excessive fumigation treatment rates.
In a chronic/oncogenicity study, Charles River Fischer CDF Rats
(60/sex/group) were exposed, under dynamic chamber conditions, to 0,
0.3, 1 and 3 ppm of phosphine. The rats were kept under standard
laboratory conditions, observed twice daily and sacrificed (10/sex/
group) during week 52 of the study. Body weights; food consumption;
routine hematologic, serum biochemical and urinary analyses were all
comparable to control animals. There were no adverse effects observed
for the initial 12 month period. Body weights;
[[Page 30942]]
food consumption; routine hematologic, serum biochemical and urinary
analyses were all comparable to control animals. Ophthalmological
observations, gross pathology, organ weights and histopathology
indicated no adverse effects from the phosphine exposures. The NOAEL
for the 52 week period was 3.0 ppm, the HDT.
4. Mutagencity. In a Salmonella typhimurium reverse gene mutation
assay, the test was negative with hydrogen phosphide (PH3)
in all strains up to cytotoxic concentrations (488 ppm/plate
+/-S9).
i. Chromosome aberrations. In an in vitro cytogenetic assay with
Chinese hamster ovary (CHO) cells phosphine was positive at 2,500 and
5,000 ppm without S9 activation. This resulted in a significant but not
dose-related increases in the frequency of cells with structural
chromosome aberrations. Significant clastogenic effects were also noted
at 2,500 ppm with S9 activation but not at the HDT (5,000 ppm).
ii. Other genotoxic mechanisms. In an in vivo unscheduled DNA
Synthesis (UDS) in primary rat hepatocytes, the test was negative in
male Fischer rats exposed via inhalation to PH3 doses of 0,
4.8, 13, 18 or 23 ppm (equiv. to 0, 11.4, 30.8, 42.6 or 54.5 mg/
m3, respectively) for 6 hours. Overt toxicity (i.e.,
difficulty in breathing) but no target cell cytotoxicity was observed
at the HTD.
Based on the findings reported by Garry et al., (1989) that
pesticide applicators exposed to phosphine had increased levels of
chromosome damage, the USEPA sponsored a series of acute (Kligerman et
al.,1994a) and subacute (Kligerman et al., 1994b) inhalation
cytogenetic studies with phosphine. A summary of these studies are as
follows:
(a) Phosphine was negative for the induction of micronucleated
polychromatic erythrocytes (MPE) in bone marrow cells and splenocytes
and negative for the induction of sister chromatid exchange or
chromosomal aberrations in splenocytes of CD-1 male mice exposed by
inhalation to 0, 5, 10 or 15 ppm for 6 hours. Overt toxicity,
manifested as lethargy and shallow breathing was seen at the HDT. There
was a dose-related and significant reduction of splenocyte cell cycling
at all levels, which indicates that phosphine was cytotoxic to
splenocytes. There was, however, no adverse effect on bone marrow cells
(Kligerman, et al., 1994).
(b) Male B6C3F1 mice and male F344 rats were exposed by inhalation
to 0, 1.25, 2.5 or 5.0 ppm phosphine, 6 hours/day, 5 days/week over an
11-day period. Bone marrow cells and/or peripheral blood lymphocytes
were harvested and examined for sister chromatid exchanges and
chromosomal aberrations (mouse and rat peripheral blood lymphocytes)
and for MPEs (rat bone marrow and mouse bone marrow and peripheral
blood lymphocytes). In addition, B6C3F1 males were exposed via
inhalation to 0 or 5 ppm as above over a 12-day period and mated with
untreated females in a dominant lethal assay. Results show that
phosphine was not genotoxic at any endpoint.
iii. Additional in vivo data summarized below were available for
review:
(a) Following subchronic inhalation exposure (0, 0.3, 1.0 or 4.5
ppm, 6 hours/ day, 5 days/week for 13 weeks) but not acute inhalation
exposure (0 or 5.5 ppm, 2 weeks, 6 hours/day, 5 days/week for 2 weeks),
phosphine at 4.5 ppm caused a statistically significant increase in
micronucleus induction in the spleen lymphocytes and bone marrow cells
of Balb-c male and female mice. There was, however, no increase in gene
mutations at the hypoxanthine guanine phosphoribosyl transferase locus
in the recovered spleen lymphocytes.
(b) After 6 hours of inhalation exposure, phosphine, at the HDT (19
ppm) induced a significant increase in chromosomal aberrations in the
bone marrow of Sprague Dawley male rats but not in the female rats. The
effect is considered equivocal because increased chromosomal aberration
frequencies were only seen in high-dose males with severely reduced
mitotic indices (MIs). Females did not show increased chromosome
aberrations and did not have decreased MIs. There was also no effect on
peripheral lymphocytes.
(c) In an Australian study of workers exposed to phosphine, 31
phosphine fumigators and 21 controls, all employed at the New South
Wales Grain Corporation, were examined for micronucleus incidence in
peripheral blood lymphocytes and their concentrated urine was assessed
for mutagenicity in TA100 and TA98 strains of S. typhimurium. In
addition, serum bile acids were measured. The subjects, all males, were
matched for medication, X-ray exposure within the past year and smoking
habits. There was no indication how often the fumigators were exposed,
or the most recent exposure date or the length of the various
fumigators employed. No individual data were presented to identify if
certain individuals showed unusually high micronuclei incidence, or
presence of mutagens in the urine.
Urine samples were concentrated 75-fold and the procedure of
Yamaski and Ames (1977) was used to test mutagenicity to TA100 and TA98
in the presence or absence of metabolic activation (S9). There was no
increase in the mutagenicity of urine from the fumigators (N-27) vs
controls (N=-19) in this assay.
Serum bile acids showed no changes related to phosphine exposure.
Cholesterol and some liver enzymes (gamma-glutamyl transferase were
elevated in the exposed group. Micronuclei formation was measured in
isolated peripheral blood lymphocytes cultured for 44 hours in the
presence of phytohemagglutinin to stimulate mitosis, arrested at
metaphase with cytochalasin-B and harvested by cytocentrifugation after
72 hours in culture. The micronucleus incidence was comparable among
the fumigators and the control groups (overall MI for fumigators = 6.9
vs 7.1 for controls).
Phosphine is not mutagenic in bacteria but is clastogenic in vitro.
Both the negative Ames test and the positive CHO cell chromosome assay
are consistent with the in vitro test results for zinc phosphide.
Studies conducted in vivo indicate that phosphine is not clastogenic in
mice or rats and does not cause dominant lethal mutations in mice
following acute exposures for up to 2 weeks. There is, however,
evidence that inhalation exposures of phosphine for up to 13 weeks
induced significant clastogenic and/or an euploidogenic effects in male
and female mice. The biological relevance of this finding can not be
fully ascertained until the results of the 2-year rat inhalation study
currently underway are submitted and reviewed.
5. Neurotoxicity. In an acute neurotoxicity study, 11
Crl:CDBR VAF/Plus rats/sex/exposure group were
exposed to 0, 20, 30, or 40 ppm of phosphine (1% a.i. in nitrogen) for
four hours. Each treatment group was exposed on a different day, with
the first exposure occurring six days prior to the final exposure. 11
rats/sex/exposure group were selected for functional observational
battery (FOB) and motor activity (MA) testing prior to and following
exposure, and on days 7 and 14 post-exposure; six rats/sex/exposure
group were perfused for neuropathology. All animals survived to
scheduled termination. There were no exposure-related clinical signs.
FOB and MA parameters were characterized by variability both within and
among control and exposed groups; this variability (which may be partly
due to the unbalanced treatment schedule) confounded interpretation of
some of
[[Page 30943]]
the results. Palpebral closure was noted in some exposed groups on day
1 and was significant in females exposed to 30 and 40 ppm and in males
at 20 and 40 ppm. Body temperatures were significantly lowered for
males and females on day 1 in all exposure groups. The remainder of the
differences in the FOB parameters were random statistical variations
that occurred both pre- and post-test, were not dose related, and were
not consistent between the sexes. Motor activity (horizontal, vertical,
total distance, and stereotypic time) was decreased at 20, 30, and 40
ppm, primarily during the 10 and 20 minute post-exposure time intervals
(data comparing motor activity for the entire 30-minute assessment
period was neither presented nor analyzed). With one exception, these
reductions no longer occurred at 7 or 14 days after exposure. For males
during the first 10-minute post-exposure interval, horizontal activity
decreased significantly by 76.4, 71.7 and 83.8% in the 20, 30, and 40
ppm groups, respectively. Males in the 20 ppm group had the following
decreases in horizontal activity: 76.4%, 77.6% (both statistically
significant), and 89.4% (non-statistically significant) during the 10,
20, and 30 minute intervals, respectively. For females during the first
10-minute post-exposure interval, horizontal activity decreased
significantly by 71.3, 48.0, and 83.5% in the 20, 30, and 40 ppm
groups, respectively. Females in the 20 ppm group had the following
decreases in horizontal activity: 71.3%, 85.8% (both significant), and
54.1% (non-statistically significant) during the 10, 20, and 30 minute
intervals, respectively. Similar decreases occurred for both sexes for
vertical activity, total distance, and stereotypic time. No phosphine-
related neuropathological changes were observed in any exposure group.
Significant increases in absolute and relative (body and brain weights)
adrenal gland weights in males from the 40 ppm group were of
questionable biological significance and did not show a concentration-
response relationship. The significant decrease in temperature and
motor activity, seen at all exposure levels in spite of the flaws in
the study, are considered treatment-related. The LOEL for
neurobehavioral findings is 20 ppm based on decreased body temperatures
and decreased motor activity in males and females. The NOAEL is <20 ppm.="" based="" on="" lack="" of="" systemic="" toxicity,="" the="" noael="" for="" systemic="" toxicity="" is="" 40="" ppm.="" it="" must="" be="" noted="" that="" the="" agency="" has="" asked="" for="" additional="" information="" regarding="" this="" study="" and="" has="" not="" accepted="" the="" study="" until="" the="" requested="" data="" are="" submitted="" and="" reviewed.="" in="" a="" subchronic="" inhalation="" neurotoxicity="" study,="" 16="">BE VAF/Plus rats/sex/exposure group were
exposed to phosphine (1% a.i. in nitrogen) for six hours/day, 5 days/
week for approximately 90 days at 0, 0.3, 1, or 3 ppm. An additional
six rats/sex were assigned to the 0 and 3 ppm groups for a 2-week
recovery group. Eleven rats/sex/exposure group were assigned for
neurobehavioral evaluations. Six of the eleven rats/sex/exposure group
were designated for neuropathological evaluations. No exposure-related
deaths occurred in this study. Body weights were slightly higher in
high-concentration males (2.4%) and females (1.2%) after 13 weeks of
treatment, and became equal or less than the control body weights after
the 2 week recovery period. Palpebral closure was consistently
increased in high-concentration animals compared to controls. The
increase was significant (p 0.05) in high-concentration
males at week 4 and was exposure related. The increased palpebral
closure in high-concentration females was not significantly different
from the control group. The incidence of high-concentration males found
sleeping was consistently higher than the controls and was
significantly higher (p 0.05) at week 4. The sleep
incidence in males showed an exposure effect at weeks 4 and 13. A
similar trend was observed in females, but the differences were not
statistically significant. Body temperatures of high-concentration
males were consistently lower than the controls and reached statistical
significance (p 0.05) at week 13. The decreased body
temperature was exposure- related at weeks 4 and 13. Females did not
show a treatment-related change in body temperature. The horizontal and
vertical motor activities were significantly lower in high-
concentration males than the control group at week 13, and were
consistently, but not significantly lower at other time intervals.
Motor activity measurements in females were compromised by high
variations and significant decreases in the high-concentration group at
the pretest interval. There were no treatment-related findings at
necropsy or during the neurohistopathological examination of collected
tissues. The effects seen in high-concentration males that could be
treatment-related are slight, but are consistent and mutually
supportive. The effects in females either did not occur, were not
statistically significant, or were compromised by variations in pretest
measurements. Due to the equivocal nature of the effects seen in high-
concentration males, and the lack of effects seen in females, the
tentative NOAEL for systemic/neurobehavioral findings is 3.0 ppm for
males and females, a LOEL was not determined in this study. Since the
procedures used in this study have not been validated, and since
positive effects may be obscured by insensitive methods, the NOAEL is
tentative and will be re-evaluated upon receipt of information
requested from the sponsor. It must be noted that the Agency has asked
for additional information regarding this study and has not accepted
the study until the requested data are submitted and reviewed.
B. Toxicological Endpoints
1. Acute toxicity. The acute dietary endpoint is based upon the
results of the 90-day inhalation study. The dose and endpoint for risk
assessment was 5 ppm or 1.8 milligrams/kilogram/day (mg/kg/day) based
on the lack of treatment-related effects following 15 days of exposure.
This includes a 100 fold Uf to account for inter and intra species
variation.
2. Short - and intermediate - term toxicity. Based on the use
pattern and the fact that phosphine is a gas, an end-point and risk
assessment were not conducted for short- and intermediate-term, oral or
dermal exposures.
3. Chronic toxicity. EPA has established the chronic reference
dose (RfD) for phosphine at 0.0113 mg/kg/day. This RfD is based on an
interim report (one year) for a 2-year chronic/oncogenicity inhalation
toxicity in rats. The dose for the risk assessment was a NOAEL=3 ppm =
0.004 mg/L=1.13 mg/kg/day. A 100 fold Uf was applied to account for
inter and intra species variation.
4. Carcinogenicity. The results of a non-guideline 2-year rat
feeding study did not indicate a carcinogenic concern. Additionally, an
interim (one year) report for a 2-year inhalation carcinogenicity study
has been reviewed and does not indicate a carcinogenic concern. The
final report was submitted to the Agency in November, 1998 and is being
reviewed; however, it is unlikely to change the Agency's evaluation of
phosphine's carcinogenic potential.
C. Exposures and Risks
1. From food and feed uses. Tolerances have been established under
(40 CFR 180.225 (a) and (b), 185.200, 186.200, 180.375, 185.3800, and
186.3800) for the residues of phosphine, in or on a variety of raw
agricultural
[[Page 30944]]
commodities at either 0.01 ppm or 0.1 ppm level including food and feed
tolerances. This rule does not propose any new tolerances but rather
changes the existing tolerance expressions and eliminates reference to
the source of the phosphine gas, i.e., generated from either aluminum
or magnesium phosphide. Tolerances are set at 0.01 ppm for those
commodities for which direct treatment is not permitted. Tolerances of
0.1 ppm were established for those commodities listed above for which
aluminum and magnesium are allowed to come into direct contact, e.g.,
tablets are added directly to corn grain as it is stored in silos . The
Agency does not expect finite residues at the consumer's dinner plate,
even for those commodities with a 0.1 ppm tolerance. This is because
these commodities are aerated for 48 hours, cooked, shelled, washed, or
otherwise prepared in some other way before they are actually consumed.
For example, nuts are shelled and further processed before reaching the
consumer. Other commodities such as dates are washed and graded for
packaging which would remove any unreacted phosphine residue. The
Agency has residue data from numerous studies on a wide variety of raw
agricultural commodities and processed foods that confirm, with
adequate aeration (48 hours is required) there will not be finite
residues in or on food commodities. Still the FDA does at times sample
RACs before the further processing described above occurs and there is
the potential that small amounts of unreacted phosphine residues of up
to 0.1 ppm could be observed in one of the RACs listed. All aluminum
and magnesium phosphide product labels are carefully reviewed to
restrict direct addition of the fumigant to commodities that are
further processed in a manner that it would preclude the possibility of
unreacted fumigant being in or on the food supply presented to the
consumer. Risk assessments were conducted by EPA to assess dietary
exposures and risks from phosphine 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. Dietary exposure to aluminum and
magnesium phosphide can potentially occur via residues of phosphine gas
remaining in treated commodities. A large number of studies involving
numerous types of raw agricultural commodities and processed
commodities submitted to the Agency for establishment of food
tolerances indicate that residues of phosphine gas will be non-
detectable with adequate aeration. One of these studies involved the
analysis of 49 different processed foods, with all residues being
<0.004 ppm="" (limit="" of="" detection="" for="" this="" study).="" there="" are="" many="" other="" studies="" cited="" in="" the="" registration="" standard="" (pb87-117172)="" that="" support="" the="" conclusion="" that="" residues="" will="" typically="" be="" non-detectable="" with="" adequate="" aeration,="" i.e.,=""><0.004 ppm.="" tolerances="" were="" established="" based="" on="" the="" limits="" of="" quantification="" of="" the="" analytical="" method="" for="" phosphine="" gas="" for="" those="" commodities="" that="" may="" not="" come="" into="" direct="" contact="" phosphine="" during="" the="" fumigation="" procedure.="" tolerances="" of="" 0.1="" ppm="" were="" established="" for="" those="" commodities="" for="" which="" aluminum="" and="" magnesium="" are="" allowed="" to="" come="" in="" direct="" contact.="" this="" tolerance="" level="" allows="" for="" any="" small="" amount="" of="" unreacted="" product="" compound="" left="" in="" the="" food="" or="" feed="" that="" would="" be="" removed="" later="" during="" processing.="" direct="" addition="" (="" with="" it's="" 0.1="" ppm="" tolerance)="" is="" not="" allowed="" for="" processed="" commodities,="" and="" is="" strictly="" prohibited="" by="" the="" product="" use="" manuals.="" anticipated="" residues,="" were="" used="" for="" both="" the="" chronic="" and="" acute="" dietary="" exposure="" analysis.="" the="" agency="" conducted="" a="" dietary="" exposure="" evaluation="" model="" (deem)="" analysis,="" for="" both="" acute="" and="" chronic="" exposure="" scenarios,="" making="" the="" very="" conservative="" assumption="" (protective="" of="" human="" health)="" that="" all="" food="" contained="" in="" the="" deem="" consumption="" database="" (except="" meat/milk/poultry/eggs),="" i.e.,="" the="" food="" consumed="" by="" an="" individual="" in="" a="" given="" day,="" would="" contain="" residues="" of="" phosphine="" gas="" at="" the="" anticipated="" residue="" level="" of="" 0.006="" ppm.="" this="" was="" the="" highest="" limit="" of="" detection="" for="" any="" of="" the="" residue="" studies="" in="" the="" agency's="" tolerance="" petition="" files="" and="" was="" used="" for="" both="" the="" acute="" and="" chronic="" analysis.="" the="" agency="" considers="" this="" to="" be="" a="" ``worst-case''="" scenario.="" acute="" dietary="" exposure="" from="" food="" does="" not="" exceed="" the="" agency's="" level="" of="" concern.="" the="" percent="" of="" the="" acute="" rfd="" occupied,="" at="" the="" 99.9th="" percentile,="" is="" less="" than="" 30%="" for="" the="" population="" subgroups="" examined.="" the="" agency="" again="" notes="" that="" tolerances="" are="" based="" upon="" non-detectable="" residues="" in="" residue="" field="" trials.="" because="" phosphine="" gas="" will="" dissipate="" into="" the="" atmosphere,="" especially="" as="" foods="" are="" cooked="" (heated)="" or="" prepared,="" residues="" are="" unlikely="" to="" be="" found="" on="" food="" at="" the="" time="" of="" consumption.="" table="" 1.="" acute="" dietary="" (food)="" exposure="" at="" the="" 99.9th="" percentile="" ------------------------------------------------------------------------="" exposure="" (mg/kg/="" population="" subgroup="" day)="" percent="" acute="" rfd="" ------------------------------------------------------------------------="" u.s.="" population...................="" 0.003872="" 22="" non-nursing="" infants=""><1 yr="" old)..="" 0.004943="" 27="" children="" (1-6="" yr="" old).............="" 0.004440="" 25="" ------------------------------------------------------------------------="" in="" addition,="" the="" acute="" dietary="" endpoint="" is="" based="" on="" a="" noael="" which="" is="" the="" highest="" dose="" in="" the="" study.="" the="" true="" noael="" may="" well="" be="" higher="" than="" that="" observed="" in="" the="" study.="" therefore,="" the="" agency="" concludes="" that="" there="" is="" a="" reasonable="" certainty="" of="" no="" harm="" from="" acute="" dietary="" exposure.="" ii.="" chronic="" exposure="" and="" risk.="" the="" results="" of="" the="" deem="" chronic="" exposure="" analysis="" for="" exposure="" are="" summarized="" in="" table="" 2.="" chronic="" exposure="" does="" not="" exceed="" the="" agency's="" level="" of="" concern.="" the="" percent="" of="" the="" chronic="" rfd="" occupied,="" is="" less="" than="" 10%="" for="" the="" population="" subgroups="" examined.="" these="" estimates="" of="" exposure="" are="" partially="" refined,="" yet="" still="" conservative="" in="" that="" it="" was="" assumed="" that="" all="" food="" (except="" meat/milk/="" poultry/eggs)="" consumed="" by="" an="" individual="" would="" contain="" phosphine="" gas="" residues="" at="" 0.006="" ppm.="" this="" anticipated="" residue="" level="" is="" based="" on="" the="" highest="" limit="" of="" detection="" reported="" in="" tolerance="" petitions.="" the="" agency="" again="" notes="" that="" all="" tolerances="" are="" based="" upon="" non-detectable="" residues="" in="" residue="" field="" trials.="" because="" phosphine="" gas="" will="" dissipate="" into="" the="" atmosphere,="" especially="" as="" foods="" are="" cooked="" (heated)="" or="" prepared,="" residues="" are="" unlikely="" to="" be="" found="" on="" food="" at="" the="" time="" of="" consumption.="" [[page="" 30945]]="" table="" 2.="" chronic="" dietary="" (food)="" exposure="" ------------------------------------------------------------------------="" exposure="" (mg/kg/="" percent="" chronic="" population="" subgroup="" day)="" rfd="" ------------------------------------------------------------------------="" u.s.="" population..................="" 0.000261="" 2="" non-nursing="" infants=""><1 yr="" old)..="" 0.001004="" 9="" children="" (1-6="" yr="" old).............="" 0.000474="" 4="" ------------------------------------------------------------------------="" chronic="" aggregate="" dietary="" exposure="" (food="" and="" water)="" does="" not="" exceed="" hed's="" level="" of="" concern.="" using="" conservative="" assumptions,="" chronic="" risk="" estimates="" from="" exposure="" in="" food="" were="" less="" than="" 10%="" for="" all="" population="" subgroups="" examined.="" in="" fact,="" due="" to="" the="" rapid="" dissipation="" of="" gaseous="" phosphine,="" the="" agency="" does="" not="" expect="" finite="" residues="" on="" treated="" commodities="" at="" all="" if="" used="" according="" to="" label="" directions.="" therefore,="" the="" agency="" concludes="" that="" there="" is="" a="" reasonable="" certainty="" of="" no="" harm="" from="" chronic="" dietary="" exposure.="" section="" 408(b)(2)(e)="" authorizes="" epa="" to="" consider="" available="" data="" and="" information="" on="" the="" anticipated="" residue="" levels="" of="" pesticide="" residues="" in="" food="" and="" the="" actual="" levels="" of="" pesticide="" chemical="" that="" have="" been="" measured="" in="" food.="" if="" epa="" relies="" on="" such="" information,="" epa="" must="" require="" that="" data="" be="" provided="" 5="" years="" after="" the="" tolerance="" is="" established,="" modified="" or="" left="" in="" effect="" demonstrating="" that="" the="" levels="" in="" food="" are="" not="" above="" the="" levels="" anticipated.="" following="" the="" initial="" data="" submission,="" epa="" is="" authorized="" to="" require="" similar="" data="" on="" a="" time="" frame="" it="" deems="" appropriate="" 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.="" 2.="" from="" drinking="" water.="" phosphine="" degrades="" in="" days="" (half-life="" is="" estimated="" to="" be="" 5="" hours)="" and="" has="" a="" low="" exposure="" potential="" for="" contaminating="" ground="" and="" surface="" water="" because="" it="" is="" a="" gas.="" therefore,="" epa="" believes="" these="" uses="" will="" not="" result="" in="" any="" exposure="" through="" ground="" or="" surface="" water.="" therefore,="" aggregate="" exposure="" is="" limited="" only="" to="" food.="" if="" new="" uses="" are="" added="" in="" the="" future,="" the="" agency="" will="" reassess="" the="" potential="" impacts="" of="" phosphine="" on="" drinking="" water="" as="" a="" part="" of="" the="" aggregate="" risk="" assessment="" process.="" due="" to="" the="" nature="" of="" these="" insecticides,="" addition="" of="" crop="" or="" residential="" uses="" is="" not="" likely.="" 3.="" from="" non-dietary="" exposure.="" phosphine="" is="" restricted="" use="" pesticide="" that="" is="" used="" to="" fumigate="" grains="" and="" other="" non-food="" commodities.="" phosphine="" is="" also="" used="" to="" control="" rodents="" in="" burrows.="" it="" has="" no="" residential="" uses.="" residential="" exposure="" is="" not="" expected;="" therefore,="" no="" risk="" assessment="" for="" these="" scenarios="" were="" conducted.="" 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="" phosphine="" 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,="" phosphine="" 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="" phosphine="" has="" a="" common="" mechanism="" of="" toxicity="" with="" other="" substances.="" d.="" aggregate="" risks="" and="" determination="" of="" safety="" for="" u.s.="" population="" 1.="" acute="" risk.="" the="" aggregate="" acute="" risk="" reflects="" food="" source="" risk="" only,="" therefore="" an="" additional="" aggregate="" risk="" assessment="" is="" not="" needed="" (see="" unit="" ii.c.2="" in="" the="" preamble="" of="" this="" document).="" the="" use="" patterns="" associated="" with="" aluminum="" and="" magnesium="" phosphide="" are="" not="" expected="" to="" impact="" water="" resources="" through="" labeled="" uses;="" therefore,="" exposure="" to="" humans="" through="" drinking="" water="" is="" not="" expected.="" in="" addition,="" all="" aluminum="" and="" magnesium="" phosphide="" products="" are="" restricted="" use="" pesticides,="" which="" have="" no="" indoor="" residential="" uses;="" therefore,="" residential="" exposure="" is="" not="" expected="" for="" these="" restricted="" use="" products="" (which="" do="" not="" have="" residential="" use="" other="" that="" rodent="" control="" in="" burrows).="" the="" acute="" risk="" from="" food="" exposure="" to="" phosphine="" is="" 22%="" of="" the="" rfd,="" which="" indicates="" an="" adequate="" margin="" of="" safety.="" 2.="" chronic="" risk.="" using="" the="" anticipated="" residues="" and="" 100%="" crop="" treated="" exposure="" assumptions="" described="" above,="" epa="" has="" concluded="" that="" aggregate="" exposure="" to="" phosphine="" from="" food="" will="" utilize="" less="" than="" 10%="" of="" the="" rfd="" for="" the="" u.s.="" population.="" the="" subgroup="" with="" the="" highest="" aggregate="" exposure="" is="" 9%="" for="" non-nursing="" infants=""><1 year="" old).="" 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.="" the="" potential="" residues="" [[page="" 30946]]="" in="" drinking="" water="" are="" considered="" to="" be="" zero;="" therefore,="" the="" combined="" exposure="" of="" chronic="" food="" and="" drinking="" water="" exposure="" to="" phosphine="" would="" be="" no="" greater="" than="" less="" than="" 10%="" of="" the="" rfd="" for="" children="" or="" the="" general="" u.s.="" population.="" due="" to="" the="" nature="" of="" the="" non-dietary="" use,="" epa="" believes="" that="" the="" commercial="" use="" of="" phosphine="" as="" a="" fumigant="" and="" in="" pest="" burrows="" will="" not="" result="" in="" any="" significant="" residential="" exposure.="" therefore="" the="" chronic="" risk="" is="" based="" on="" food="" only.="" 3.="" short-="" and="" intermediate-term="" risk.="" short-="" and="" intermediate-="" term="" risks="" are="" assessed="" in="" tolerance="" actions="" where="" a="" pesticide="" has="" the="" potential="" for="" residential="" exposure="" through="" a="" route="" other="" than="" the="" diet.="" no="" such="" potential="" exists="" for="" phosphine.="" the="" acute="" and="" chronic="" risk="" assessments="" fully="" capture="" the="" risks="" associated="" with="" this="" tolerance="" action.="" 4.="" aggregate="" cancer="" risk="" for="" u.s.="" population.="" epa="" has="" determined="" that="" there="" is="" no="" evidence="" of="" carcinogenicity="" in="" the="" available="" studies.="" based="" upon="" this="" determination="" it="" can="" be="" concluded="" that="" phosphine="" does="" not="" pose="" a="" cancer="" risk.="" 5.="" conclusion.="" the="" agency="" concludes="" that="" there="" is="" reasonable="" certainty="" that="" no="" harm="" will="" result="" from="" aggregate="" exposure="" to="" phosphine="" residues.="" e.="" aggregate="" risks="" and="" determination="" of="" safety="" for="" infants="" and="" children="" and="" the="" general="" population="" 1.="" safety="" factor="" for="" infants="" and="" children--="" i.="" in="" general.="" in="" assessing="" the="" potential="" for="" additional="" sensitivity="" of="" infants="" and="" children="" to="" residues="" of="" phosphine,="" epa="" considered="" data="" from="" a="" prenatal="" inhalation="" developmental="" toxicity="" study="" in="" rats.="" 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="" moe="" and="" 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.="" developmental="" toxicity="" studies.="" in="" a="" developmental="" study,="" cd="" derived="" sprague="" dawley="" mated="" female="" rats="" (24-27/dosage="" group)="" were="" exposed="" in="" inhalation="" chambers="" to="" concentrations="" of="" phosphine="" gas="" at="" 0,="" 0.03,="" 0.3,="" 3.0,="" 5.0="" and="" 7.5="" ppm,="" 6="" hours="" per="" day="" on="" gestation="" days="" 6="" through="" 15.="" the="" highest="" dose="" group="" was="" terminated="" after="" 10="" days="" of="" exposures="" due="" to="" high="" mortalities="" (14/24).="" the="" treated="" females="" were="" observed="" twice="" daily="" for="" toxicity,="" and="" body="" weights="" and="" food="" consumption="" were="" monitored="" throughout="" the="" study.="" at="" day="" 20="" post-coitus,="" the="" females="" were="" sacrificed="" and="" examined="" for="" corpora="" lutea,="" implantations,="" live="" and="" dead="" fetuses="" and="" early="" and="" late="" resorptions.="" pups="" were="" identified,="" sexed="" and="" examined="" for="" external="" malformations="" and="" visceral="" and="" skeletal="" defects.="" the="" females="" and="" their="" fetuses="" from="" the="" high="" dose="" group="" were="" not="" examined="" for="" developmental="" effects.="" the="" only="" abnormalities="" observed="" were="" increased="" resorptions="" in="" liters="" (16="" litters,="" 76="" pups).="" increased="" resorptions="" were="" not="" seen="" in="" the="" 0.3,="" 3.0="" or="" 5.0="" ppm="" groups.="" all="" other="" observations="" were="" comparable="" to="" the="" control="" females="" and="" pups.="" the="" maternal="" noael="" was="" 5="" ppm="" and="" the="" maternal="" lel="" was="" 7.5="" ppm="" based="" on="" the="" high="" incidence="" of="" maternal="" deaths.="" the="" reproductive="" noael="" is="" 5="" ppm="" and="" the="" developmental="" noael="" was="" 5="" ppm.="" iii.="" reproductive="" toxicity="" study.="" this="" study="" was="" not="" required="" for="" aluminum="" and="" magnesium="" phosphide.="" the="" complete="" toxicology="" data="" requirements="" for="" food-="" use="" chemicals="" are="" not="" required="" for="" aluminum="" and="" magnesium="" phosphide="" since="" little="" phosphine="" exposure="" is="" expected="" from="" use="" on="" foods="" as="" a="" fumigant.="" in="" fact,="" the="" agency="" does="" not="" routinely="" require="" the="" standard="" toxicological="" data="" base="" for="" a="" food="" use="" chemical="" for="" fumigants.="" fumigants="" are="" gases,="" which="" dissipate="" rapidly="" and="" provide="" for="" no="" residual="" control.="" phosphine="" diffuses="" rapidly="" through="" the="" stored="" product="" because="" it="" is="" a="" small="" molecule="" and="" does="" not="" absorb="" to="" most="" commodities.="" dietary="" exposure="" to="" this="" gas="" is="" not="" expected,="" tolerances="" are="" established="" to="" prevent="" misuse="" of="" the="" fumigants.="" it="" is="" for="" this="" reason,="" lack="" of="" exposure,="" that="" the="" agency="" does="" not="" routinely="" require="" the="" complete="" battery="" of="" testing="" required="" for="" a="" food-use="" chemical,="" for="" fumigants.="" the="" very="" nature="" of="" the="" chemicals="" used="" for="" fumigation="" (very="" high="" volatility)="" make="" dietary="" exposure="" an="" unlikely="" scenario.="" the="" agency="" reevaluated="" all="" previously="" waived="" food-="" use="" data="" requirements="" while="" reassessing="" these="" fumigants="" and="" determined="" that,="" based="" on="" lack="" of="" expected="" exposure,="" the="" data="" were="" not="" required.="" the="" only="" exception="" to="" this="" is="" the="" 2-year="" combined="" cancer-chronic="" study="" because="" there="" were="" specific="" concerns="" regarding="" chronic="" effects="" from="" low="" level="" exposure="" in="" grain="" workers.="" iv.="" pre-="" and="" post-natal="" sensitivity.="" the="" available="" toxicology="" data="" indicate="" no="" increased="" susceptibility="" in="" utero="" and/or="" postnatal="" exposure="" to="" phosphine.="" aluminum/magnesium="" phosphide="" developmental="" toxicity="" to="" the="" offspring="" occurred="" at="" equivalent="" or="" higher="" doses="" than="" maternal="" toxicity.="" v.="" conclusion.="" the="" data="" base="" is="" considered="" complete,="" with="" respect="" to="" the="" usual="" data="" requirements="" for="" fumigants="" (see="" section="" e1iii="" above).="" there="" are="" no="" data="" gaps.="" the="" toxicity="" data="" for="" phosphine="" does="" not="" indicate="" increased="" susceptibility="" in="" utero="" or="" postnatal.="" exposure="" assessments="" do="" not="" indicate="" a="" concern="" of="" potential="" risk="" to="" children="" because="" phosphine="" residues="" are="" not="" expected="" in="" food="" or="" drinking="" water="" and="" there="" is="" only="" a="" minor="" use="" of="" phosphine="" near="" residential="" sites,="" i.e.,="" control="" of="" rodents="" in="" burrows.="" in="" addition,="" the="" agency="" conducted="" a="" very="" conservative="" exposure="" assessment,="" i.e.,="" protective="" of="" human="" health.="" it="" is="" for="" all="" these="" reasons="" that="" the="" agency="" concludes="" that="" the="" additional="" safety="" factor="" of="" 10="" can="" be="" removed.="" based="" on="" these="" risks="" epa="" concludes="" that="" there="" is="" reasonable="" certainty="" that="" no="" harm="" will="" result="" to="" infants="" and="" children="" or="" the="" general="" population="" from="" aggregate="" exposure="" to="" phosphine="" residues.="" iii.="" other="" considerations="" a.="" metabolism="" in="" plants="" and="" animals="" based="" on="" the="" limited="" use="" pattern="" of="" aluminum="" and="" magnesium="" phosphide,="" plant="" and="" animal="" metabolism="" data="" were="" not="" required.="" the="" residue="" of="" concern="" is="" phosphine.="" the="" agency="" has="" determined="" that="" decomposition="" products="" of="" phosphine="" are="" toxicologically="" insignificant="" at="" the="" levels="" found="" in="" treated="" commodities.="" b.="" analytical="" enforcement="" methodology="" the="" pesticide="" analytical="" manual="" (pam)="" vol.="" ii="" lists,="" under="" aluminum="" phosphide,="" a="" colorimetric="" method="" (lod="0.01)" and="" a="" glc="" method="" with="" a="" flame="" photometric="" detection="" (lod="0.001" ppm)="" as="" method="" a="" and="" b,="" respectively,="" for="" the="" enforcement="" of="" tolerances.="" the="" residue="" of="" concern="" is="" phosphine.="" it="" is="" noted="" that="" method="" a="" remains="" a="" lettered="" method="" because="" of="" variable="" recoveries="" observed="" in="" an="" agency="" method="" try-out.="" however,="" the="" method="" has="" been="" determined="" to="" be="" acceptable="" for="" enforcement="" because="" phosphine="" is="" highly="" reactive,="" and="" finite="" residues="" are="" [[page="" 30947]]="" not="" expected.="" data="" submitted="" in="" support="" of="" the="" established="" tolerances="" were="" collected="" by="" one="" of="" these="" two="" methods.="" the="" original="" reregistration="" standards="" for="" aluminum="" and="" magnesium="" phosphide="" reserved="" the="" requirements="" for="" human="" health="" studies="" until="" certain="" uncharacterized="" residues="" which="" resulted="" from="" the="" treatment="" of="" food="" were="" characterized="" and="" evaluated.="" subsequent="" to="" the="" issuance="" of="" the="" reregistration="" standards,="" the="" agency="" received="" information="" which="" identified="" these="" formerly="" unknown="" residues="" as="" oxidation="" products="" of="" phosphine.="" having="" reviewed="" these="" data,="" the="" agency="" has="" concluded="" that="" these="" decomposition="" products="" of="" phosphine="" are="" toxicologically="" insignificant="" at="" the="" levels="" found="" in="" the="" treated="" commodities.="" because="" aluminum="" and="" magnesium="" phosphide="" are="" inorganic="" compounds,="" recovery="" of="" residues="" using="" fda="" multiresidue="" protocols="" is="" not="" expected,="" and="" the="" requirement="" for="" such="" data="" is="" waived.="" c.="" magnitude="" of="" residues="" residue="" data="" reflecting="" registered="" postharvest="" treatments="" of="" stored="" raw="" agricultural="" and="" processed="" commodities="" indicate="" that,="" with="" adequate="" aeration="" or="" further="" processing="" after="" treatment,="" residues="" of="" phosphine="" dissipate="" to="" nondetectable="" levels="" (all=""><0.01 ppm).="" residue="" data="" also="" indicate="" that="" the="" phosphine="" release="" from="" registered="" aluminum="" and="" magnesium="" phosphide="" products="" are="" not="" significantly="" different.="" since="" aluminum="" and="" magnesium="" phosphide="" have="" essentially="" identical="" use="" patterns,="" the="" available="" residue="" data="" for="" aluminum="" phosphide="" has="" been="" translated="" to="" magnesium="" phosphide.="" existing="" tolerances="" reflect="" a="" 48-="" hour="" aeration="" period.="" d.="" international="" residue="" limits="" the="" following="" tolerances="" for="" phosphine="" residues="" have="" been="" established="" by="" the="" codex="" alimentary="" commission:="" cereal="" grains,="" 0.1="" ppm;="" cocoa="" beans,="" 0.01="" ppm;="" dried="" fruits,="" 0.01="" ppm;="" dried="" vegetables,="" 0.01="" ppm;="" peanuts,="" 0.01="" ppm;="" spices,="" 0.01="" ppm;="" tree="" nuts,="" 0.01="" ppm.="" these="" tolerance="" levels="" are="" at="" or="" below="" the="" equivalent="" u.s.="" tolerances="" levels.="" the="" u.s.="" has="" no="" tolerances="" for="" use="" on="" spices="" or="" a="" broad="" tolerance="" for="" use="" on="" cereal="" grains;="" however,="" use="" on="" specific="" grains="" are="" registered="" uses="" in="" the="" u.s..="" no="" u.s.="" registrants="" are="" apparently="" interested="" in="" obtaining="" such="" a="" tolerance="" for="" the="" cereal="" grains="" crop="" group="" (crop="" group="" 15)="" or="" an="" import="" tolerance="" for="" residues="" in/on="" spices.="" the="" lower="" tolerances="" probably="" reflects="" codex="" tolerances="" that="" do="" not="" allow="" direct="" addition="" of="" the="" fumigant="" to="" the="" raw="" agricultural="" commodity.="" provided="" that="" one="" of="" the="" registrants="" submits="" a="" petition,="" with="" the="" supporting="" codex="" residue="" data="" and="" any="" corresponding="" use="" restriction,="" requesting="" that="" the="" higher="" u.s.="" tolerances="" (0.1="" ppm)="" be="" reduced="" to="" 0.01="" ppm,="" the="" agency="" anticipates="" that="" harmonization="" for="" all="" commodities="" would="" be="" possible.="" the="" agency="" notes="" that="" by="" changing="" the="" tolerance="" expression,="" new="" application="" technology="" could="" be="" registered="" that="" would="" eliminate="" the="" possibility="" of="" unreacted="" residues="" resulting="" from="" direct="" addition="" of="" the="" fumigant="" to="" raw="" agricultural="" commodities.="" e.="" rotational="" crop="" restrictions="" rotational="" crop="" restrictions="" are="" not="" needed="" as="" these="" insecticides="" are="" not="" used="" on="" agricultural="" crops.="" iv.="" conclusion="" tolerances="" are="" being="" revised="" and="" consolidated="" for="" residues="" of="" phosphine="" in="" the="" food="" commodities="" as="" outlined="" in="" the="" tables="" below.="" none="" of="" these="" proposed="" tolerances="" are="" new,="" the="" agency="" is="" merely="" changing="" the="" tolerance="" expression="" to="" eliminate="" references="" concerning="" how="" the="" phosphine="" gas="" is="" generated.="" v.="" public="" comment="" procedures="" epa="" invites="" interested="" persons="" to="" submit="" written="" comments,="" information,="" or="" data="" in="" response="" to="" this="" proposed="" rule.="" after="" consideration="" of="" comments,="" epa="" may="" issue="" a="" final="" rule.="" such="" rule="" will="" be="" subject="" to="" objections.="" failure="" to="" file="" an="" objection="" within="" the="" appointed="" period="" will="" constitute="" waiver="" of="" the="" right="" to="" raise="" in="" further="" proceedings="" issues="" resolved="" in="" the="" final="" rule.="" although="" the="" standard="" comment="" period="" on="" tolerance="" proposals="" issued="" by="" epa="" is="" 60="" days,="" epa="" finds="" for="" good="" cause="" that="" it="" would="" be="" in="" the="" public="" interest="" to="" have="" a="" comment="" period="" of="" only="" 30="" days="" on="" this="" proposal.="" this="" proposed="" tolerance="" will="" allow="" registration="" under="" the="" federal="" insecticide,="" fungicide,="" and="" rodenticide="" act="" of="" phosphine="" gas="" as="" an="" insecticide.="" currently,="" phosphine="" gas="" is="" used="" as="" a="" insecticide="" but="" only="" when="" applied="" by="" means="" of="" the="" registered="" pesticides="" magnesium="" phosphide="" or="" aluminum="" phosphide.="" application="" of="" phosphine="" gas="" directly="" will="" serve="" as="" a="" replacement="" for="" the="" use="" of="" methyl="" bromide="" as="" a="" fumigant.="" methyl="" bromide="" use="" is="" generally="" being="" phased="" out="" in="" the="" united="" states="" and="" worldwide="" under="" the="" montreal="" protocol="" due="" to="" concerns="" with="" ozone="" depleting="" compounds.="" finding="" replacements="" for="" methyl="" bromide's="" insecticidal="" uses="" is="" a="" top="" priority="" for="" epa.="" additionally,="" use="" of="" phosphine="" gas="" directly="" may="" reduce="" risks="" to="" workers.="" vi.="" public="" docket="" and="" electronic="" submissions="" the="" official="" record="" for="" this="" rulemaking,="" as="" well="" as="" the="" public="" version,="" has="" been="" established="" for="" this="" rulemaking="" under="" docket="" control="" number="" [opp-300865]="" (including="" comments="" and="" data="" submitted="" electronically="" as="" described="" below).="" 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="" official="" rulemaking="" record="" is="" located="" at="" the="" virginia="" address="" in="" ``addresses''="" at="" the="" beginning="" of="" this="" document.="" electronic="" comments="" can="" 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. Comment and data
will also be accepted on disks in Wordperfect 5.1/6.1 or ASCII file
format. All comments and data in electronic form must be identified by
the docket control number [OPP-300865]. Electronic comments on this
proposed rule may be filed online at many Federal Depository Libraries.
VII. Regulatory Assessment Requirements
Under Executive Order 12866 (58 FR 51735, October 4, 1993), this
action is not a ``significant regulatory action'' and since this action
does not impose any information collection requirements subject to
approval under the Paperwork Reduction Act, 44 U.S.C. 3501 et. seq., it
is not subject to review by the Office of Management and Budget. In
addition, this action does not impose any enforceable duty, or contain
any ``unfunded mandates'' as described in Title II of the Unfunded
Mandates Reform Act of 1995 (Public Law 104-4), or require prior
consultation as specified by executive Order 12875 (58 FR 58093,
October 28, 1993), or special considerations as required by Executive
Order 12898 (59 FR 7629, February 16, 1994).
Pursuant to the requirements of the Regulatory Flexibility Act
(Public Law 96-354, 94 Stat. 1164, 5 U.S.C. 601-612), the Administrator
has determined that regulations establishing exemptions from tolerance
requirements do not have a significant economic impact on a substantial
number of small entities. A
[[Page 30948]]
certification statement explaining the factual basis for this
determination was published in the Federal Register of May 4, 1981 (46
FR 24950).
A. Executive Order 12875
Under Executive Order 12875, entitled Enhancing Intergovernmental
Partnerships (58 FR 58093, October 28, 1993), EPA may not issue a
regulation that is not required by statute and that creates a mandate
upon a State, local or tribal government, unless the Federal government
provides the funds necessary to pay the direct compliance costs
incurred by those governments. If the mandate is unfunded, EPA must
provide to the Office of Management and Budget (OMB) a description of
the extent of EPA's prior consultation with representatives of affected
State, local and tribal governments, the nature of their concerns,
copies of any written communications from the governments, and a
statement supporting the need to issue the regulation. In addition,
Executive Order 12875 requires EPA to develop an effective process
permitting elected officials and other representatives of State, local
and tribal governments ``to provide meaningful and timely input in the
development of regulatory proposals containing significant unfunded
mandates.''
Today's proposed rule does not create an unfunded federal mandate
on State, local or tribal governments. The rule does not impose any
enforceable duties on these entities. Accordingly, the requirements of
section 1(a) of Executive Order 12875 do not apply to this rule.
B. Executive Order 13084
Under Executive Order 13084, entitled Consultation and Coordination
with Indian Tribal Governments (63 FR 27655, May 19,1998), EPA may not
issue a regulation that is not required by statute, that significantly
or uniquely affects the communities of Indian tribal governments, and
that imposes substantial direct compliance costs on those communities,
unless the Federal government provides the funds necessary to pay the
direct compliance costs incurred by the tribal governments. If the
mandate is unfunded, EPA must provide OMB, in a separately identified
section of the preamble to the rule, a description of the extent of
EPA's prior consultation with representatives of affected tribal
governments, a summary of the nature of their concerns, and a statement
supporting the need to issue the regulation. In addition, Executive
Order 13084 requires EPA to develop an effective process permitting
elected and other representatives of Indian tribal governments ``to
provide meaningful and timely input in the development of regulatory
policies on matters that significantly or uniquely affect their
communities.''
Today's proposed rule does not significantly or uniquely affect the
communities of Indian tribal governments. This action does not involve
or impose any requirements that affect Indian Tribes. Accordingly, the
requirements of section 3(b) of Executive Order 13084 do not apply to
this rule.
List of Subjects
40 CFR Part 180
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
40 CFR Part 185
Environmental protection, Food additives, Pesticides and pests.
40 CFR Part 186
Environmental protection, Animal feeds, Pesticides and pests.
Dated: May 25, 1999.
James Jones
Director, Registration Division.
Therefore, it is proposed that 40 CFR chapter 1 be amended as
follows.
PART 180--[AMENDED]
1. In part 180:
a. The authority citation for part 180 continues to read as
follows:
Authority: 21 U.S.C. 321(q), 346(a) and 371.
b. Section 180.225 is revised to read as follows:
Sec. 180.225 Phosphine; tolerances for residues.
(a) General. (1) Tolerances are established for residues of the
insecticide phosphine in or on the following raw agricultural
commodities resulting from post-harvest fumigation:
------------------------------------------------------------------------
Commodity Parts per million
------------------------------------------------------------------------
Almond, nutmeat...................................... 0.1
Avocadoes............................................ 0.01
Bananas (includes Plantains)......................... 0.01
Barley, grain........................................ 0.1
Brazil nuts.......................................... 0.1
Cabbage, Chinese..................................... 0.01
Cacao bean........................................... 0.1
Cashews.............................................. 0.1
Citrus citron........................................ 0.01
Cocoa bean........................................... 0.1
Coffee, bean, green.................................. 0.1
Corn, field, grain................................... 0.1
Corn, pop, grain..................................... 0.1
Cotton, seed, undelinted............................. 0.1
Date, dried.......................................... 0.1
Eggplants............................................ 0.01
Endive/Ecarole....................................... 0.01
Filberts............................................. 0.1
Grapefruit........................................... 0.01
Kumquats............................................. 0.01
Lemons............................................... 0.01
Lettuce.............................................. 0.01
Limes................................................ 0.01
Mangoes.............................................. 0.01
Legume vegetables (succulent or dried group, 0.01
excluding soybeans).................................
Millet, grain........................................ 0.1
Mushrooms............................................ 0.01
Oats................................................. 0.1
Oranges.............................................. 0.01
Papayas.............................................. 0.01
Peanut, nutmeat...................................... 0.1
Pecans............................................... 0.1
Peppers.............................................. 0.01
Persimmons........................................... 0.01
Pimentos............................................. 0.01
Pistachio............................................ 0.1
Rice, grain.......................................... 0.1
Rye, grain........................................... 0.1
Safflower, seed...................................... 0.1
Salsify tops......................................... 0.01
Sesame, seed......................................... 0.1
Sorghum, grain....................................... 0.1
Soybeans............................................. 0.1
Sunflower, seed...................................... 0.1
Sweet potatoes....................................... 0.01
Tangelos............................................. 0.01
Tangerines........................................... 0.01
Tomatoes............................................. 0.01
Walnuts.............................................. 0.1
Wheat................................................ 0.1
------------------------------------------------------------------------
(2) Tolerances are established for residues of the fumigant
phosphine in or on all raw agricultural commodities (RAC) resulting
from preharvest treatment of pest burrows in agricultural and non-crop
land areas as listed in the following table:
------------------------------------------------------------------------
Commodity Parts per million
------------------------------------------------------------------------
All RACs resulting from preharvest treatment of pest 0.01
burrows.............................................
------------------------------------------------------------------------
(3) Residues resulting from fumigation of processed foods:
------------------------------------------------------------------------
Commodity Parts per million
------------------------------------------------------------------------
Processed foods...................................... 0.01
------------------------------------------------------------------------
[[Page 30949]]
(4) Residues resulting from fumigation of animal feeds:
------------------------------------------------------------------------
Commodity Parts per million
------------------------------------------------------------------------
Animal feeds......................................... 0.01
------------------------------------------------------------------------
(5) To assure safe use of this pesticide, it must be used in
compliance with the labeling conforming to that registered by the U.S.
Environmental Protection Agency (EPA) under FIFRA. Labeling shall bear
a restriction to aerate the finished food for 48 hours before it is
offered to the consumer, unless EPA specifically determines that a
different time period is appropriate. Where appropriate, a warning
shall state that under no condition should any formulation containing
aluminum or magnesium phosphide be used so that it will come in contact
with any processed food, except processed brewer's rice, malt, and corn
grits stored in breweries for use in the manufacture of beer.
(b) Section 18 emergency exemptions. [Reserved]
(c) Tolerances with regional registrations. [Reserved]
(d) Indirect or inadvertent residues. [Reserved]
Sec. 180.375 [Removed]
b. Section 180.375 is removed.
PART 185--[AMENDED]
2. In part 185:
a. The authority citation for part 185 continues to read as
follows:
Authority: 21 U.S.C. 346a and 348.
Sec. 185.200 [Removed]
b. Section 185.200 is removed.
Sec. 185.3800 [Removed]
c. Section 185.3800 is removed.
PART 186--[AMENDED]
3. In part 186:
a. The authority citation for part 186 continues to read as
follows:
Authority: 21 U.S.C. 342, 348, and 371.
Sec. 186.200 [Removed]
b. Section 186.200 is removed.
Sec. 186.3800 [Removed]
c. Section 186.3800 is removed.
[FR Doc. 99-14069 Filed 6-8-99; 8:45 am]
BILLING CODE 6560-50-F
