[Federal Register Volume 74, Number 110 (Wednesday, June 10, 2009)]
[Rules and Regulations]
[Pages 27447-27454]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-13476]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2007-0395; FRL-8412-1]


Residues of Silver in Foods from Food Contact Surface Sanitizing 
Solutions; Exemption from the Requirement of a Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation amends the exemption from the requirement of a 
tolerance for residues of silver (excludes silver salts) in or on all 
foods when applied or used in public eating places, dairy processing 
equipment, and food-processing equipment. ETO H2O, Inc., submitted a 
petition to EPA under the Federal Food, Drug, and Cosmetic Act 
requesting to establish concentration limits for silver in end-use 
solutions eligible for tolerance exemption. The regulation being 
established will exempt all foods from the requirement of a tolerance 
for residues of silver resulting from contact with surfaces treated 
with solutions in which the end-use concentration of silver is not to 
exceed 50 parts per million (ppm).

DATES: This regulation is effective June 10, 2009. Objections and 
requests for hearings must be received on or before August 10, 2009 and 
must be filed in accordance with the itructions provided in 40 CFR part 
178 (see also Unit I.C. of the SUPPLEMENTARY INFORMATION).

ADDRESSES: EPA has established a docket for this action under docket 
identification (ID) number EPA-HQ-OPP-2007-0395. To access the 
electronic docket, go to http://www.regulations.gov, select ``Advanced 
Search,'' then ``Docket Search.'' Insert the docket ID number where 
indicated and select the ``Submit'' button. Follow the instructions on 
the regulations.gov web site to view the docket index or access 
available documents. All documents in the docket are listed in the 
docket index available in regulations.gov. Although listed in the 
index, some information is not publicly available, e.g., Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Certain other material, such as copyrighted 
material, is not placed on the Internet and will be publicly available 
only in hard copy form. Publicly available docket materials are 
available either in the electronic docket at http://www.regulations.gov, or, if only available in hard copy, at the Office 
of Pesticide Programs (OPP) Regulatory Public Docket in Rm. S-4400, One 
Potomac Yard (South Building), 2777 S. Crystal Drive Arlington, VA. The 
hours of operation of this Docket Facility are from 8:30 a.m. to 4 
p.m., Monday through Friday, excluding legal holidays. The Docket 
telephone number is (703) 305-5805.

FOR FURTHER INFORMATION CONTACT: Marshall Swindell, Antimicrobials 
Division (7510P), Office of Pesticide Programs, Environmental 
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-
0001; telephone number: (703) 308-6341; e-mail address: 
<a href="/cdn-cgi/l/email-protection#d9aaaeb0b7bdbcb5b5f7b4b8abaab1b8b599bca9b8f7beb6af"><span class="__cf_email__" data-cfemail="94e7e3fdfaf0f1f8f8baf9f5e6e7fcf5f8d4f1e4f5baf3fbe2">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may be potentially affected by this action if you are a dairy 
cattle milk producer, food manufacturer, or beverage manufacturer. 
Potentially affected entities may include, but are not limited to:
    <bullet> Food Manufacturing (NAICS code 311).
    <bullet> Beverage Manufacturing (NAICS code 3121).
    <bullet> Dairy Cattle Milk Production (NAICS code 11212).
    This listing is not intended to be exhaustive, but rather provides 
a guide for readers regarding entities likely to be affected by this 
action. Other types of entities not listed in this unit could also be 
affected. The North American Industrial Classification System (NAICS) 
codes have been provided to assist you and others in determining 
whether this action might apply to certain entities. To determine 
whether you or your business may be affected by this action, you should 
carefully examine the applicability provisions in 40 CFR 180.940 (a) 
Tolerance exemptions for active and inert ingredients for use in 
antimicrobial formulations (Food-contact surface sanitizing solutions). 
If you have any questions regarding the applicability of this action to 
a particular entity, consult the person listed under FOR FURTHER 
INFORMATION CONTACT.

 B. How Can I Access Electronic Copies of this Document?

    In addition to accessing an electronic copy of this Federal 
Register document through the electronic docket at http://

[[Page 27448]]

www.regulations.gov, you may access this Federal Register document 
electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr. You may also access a 
frequently updated electronic version of 40 CFR part 180 through the 
Government Printing Office's pilot e-CFR site at http://www.gpoaccess.gov/ecfr.

C. Can I File an Objection or Hearing Request?

    Under section 408(g) of the FFDCA, as amended by the FQPA, any 
person may file an objection to any aspect of this regulation and may 
also request a hearing on those objections. The EPA procedural 
regulations which govern the submission of objections and requests for 
hearings appear in 40 CFR part 178. You must file your objection or 
request a hearing on this regulation in accordance with the 
instructions provided in 40 CFR part 178. To ensure proper receipt by 
EPA, you must identify docket ID number EPA-HQ-OPP-2007-0395 in the 
subject line on the first page of your submission. All requests must be 
in writing, and must be mailed or delivered to the Hearing Clerk on or 
before August 10, 2009.
    In addition to filing an objection or hearing request with the 
Hearing Clerk as described in 40 CFR part 178, please submit a copy of 
the filing that does not contain any CBI for inclusion in the public 
docket that is described in ADDRESSES. Information not marked 
confidential pursuant to 40 CFR part 2 may be disclosed publicly by EPA 
without prior notice. Submit your copies, identified by docket ID 
number EPA-HQ-OPP-2007-0395, by one of the following methods:
    <bullet> Federal eRulemaking Portal: http://www.regulations.gov. 
Follow the on-line instructions for submitting comments.
    <bullet> Mail: Office of Pesticide Programs (OPP) Regulatory Public 
Docket (7502P), Environmental Protection Agency, 1200 Pennsylvania 
Ave., NW.,Washington, DC 20460-0001.
    <bullet> Delivery: OPP Regulatory Public Docket (7502P), 
Environmental Protection Agency, Rm. S-4400, One Potomac Yard (South 
Building), 2777 S. Crystal Drive, Arlington, VA. Deliveries are only 
accepted during the Docket's normal hours of operation (8:30 a.m. to 4 
p.m., Monday through Friday, excluding legal holidays). Special 
arrangements should be made for deliveries of boxed information. The 
docket telephone number is (703) 305-5805.

II. Background and Statutory Findings

    In the Federal Register of July 11, 2007 (72 FR 37779) (FRL-8136-
1), EPA issued a notice pursuant to section 408(d)(3) of the FFDCA, 21 
U.S.C. 346a(d)(3), announcing the filing of an pesticide tolerance 
petition (PP 7F7178) by ETO H20, Inc, 1725 Gillespie Way, El Cajon, CA 
92020. The petition requested that 40 CFR 180.940(a) be amended by 
establishing concentration limits for Silver in end-use solutions 
eligible for the tolerance exemption in all foods from treatment of 
food contact surfaces in public eating establishments, dairy processing 
equipment, and food processing equipment and utensils not to exceed 
silver at 50 ppm. The notice referenced a summary of the petition 
prepared by ETO H20, Inc., 90 Boroline Rd Allendale, NJ 07401, the 
registrant, which is available to the public in the docket at 
www.regulations.gov, Docket ID Number EPA-HQ-OPP-2007-0395. There were 
no comments received in response to the notice of filing.
    In drafting the regulatory language for this exemption, EPA has 
adopted more restrictive language than suggested in the petition to 
ensure that the scope of the exemption does not exceed the form of 
silver evaluated in the risk assessment supporting this action. As 
revised, the tolerance expression would now read:

    Silver ions resulting from the use of electrolytically-generated 
silver ions stabilized in citric acid as silver dihydrogen citrate 
(does not include metallic silver).

This revised tolerance expression excludes any other silver-containing 
compounds whether they are other silver salts, complexes with inorganic 
polymers such as zeolites, or metallic silver in any form or dimension 
including nanoscale.
    EPA understands that this petition was not intended to extend to 
silver salts accordingly EPA has modified the regulatory language to 
make this clear.
    Section 408(c)(2)(A)(i) of the FFDCA allows EPA to establish an 
exemption from the requirement for 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(c)(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. Pursuant to section 408(c)(2)(B), in 
establishing or maintaining in effect an exemption from the requirement 
of a tolerance, EPA must take into account the factors set forth in 
section 408(b)(2)(C), which requires EPA to give special consideration 
to exposure of infants and children to the pesticide chemical residue 
in establishing a tolerance and to ``ensure that there is a reasonable 
certainty that no harm will result to infants and children from 
aggregate exposure to the pesticide chemical residue....''
    EPA performs a number of analyses to determine the risks from 
aggregate exposure to pesticide residues. First, EPA determines the 
toxicity of pesticides. Second, EPA examines exposure to the pesticide 
through food, drinking water, and through other exposures that occur as 
a result of pesticide use in residential settings.

III. Toxicological Profile

A. Toxic Effects

    Consistent with section 408(b)(2)(D) of FFDCA, EPA has reviewed the 
available scientific data and other relevant information in support of 
this action and considered its validity, completeness and reliability 
and the relationship of this information to human risk. EPA has also 
considered available information concerning the variability of the 
sensitivities of major identifiable subgroups of consumers, including 
infants and children. The nature of the toxic effects caused by silver 
are discussed in this unit.
    Silver ions and preparations containing silver in an ionic state 
have been used for over a century for medicinal and bactericidal 
purposes. Because of its bactericidal properties, silver has been used 
as a topical treatment for burns, as a treatment for venereal diseases, 
as an ingredient in cosmetic formulations and in the sanitation of 
swimming pools and hot tubs/spas. Silver has also been used in 
dentistry (as amalgams and as an ingredient in mouth washes), in 
acupuncture, jewelry making, and photography. Silver can be found in 
electroplating as well as in paints and in water purification systems.
     The toxicity of silver is well understood based on epidemiological 
data from humans, toxicology data in animals, and documented 
information on the metabolism of silver in mammalian species. Unlike 
for other pesticides, EPA does not have a conventional check-list of 
guideline laboratory animal studies to assess human risk from exposure 
to silver. Based on the extensive past uses of

[[Page 27449]]

silver and EPA's knowledge and experience about those uses of the 
compound, however, it is apparent that humans and laboratory animals do 
not handle elevated doses of silver in the same manner. For this 
reason, additional conventional laboratory animal toxicity studies 
would not provide a better understanding of the effects of silver in 
humans. Further, the Agency has determined that silver and several of 
its salts (chloride, sulfate nitrate and acetate) can be reviewed 
together because these silver salts react similarly in aqueous media 
and the major active ion is the silver ion.
    A human biomonitoring study conducted in 1935, as reported in the 
Journal of the American Medical Association by L.E. Gaul and H.E. 
Staud, has served as the basis for establishing regulatory limits for 
silver in drinking water and in the diet. The results from this study 
were further supported by the results from an inhalation study 
conducted by Pillsbury and Hill in 1939, which established inhalation 
limits for silver in humans. In both studies, the effect of concern was 
argyria, a bluish discoloration of the skin. Argyria, while a permanent 
condition, is a cosmetic condition. The function of the skin as an 
organ is not compromised and the resulting discoloration is not 
associated with systemic toxicity. In the 1935 study by Gaul and Staud, 
silver was administered for medicinal purposes to 70 patients for 
periods from 2 to 9 years. Of the 70 patients receiving medicinal 
silver, 1/70 developed argyria after receiving an intravenous dose of 1 
gram. This intravenous dose was converted to an oral dose of 0.014 
milligram/kilogram/day (mg/kg/day) and was considered a lowest observed 
effect level. Other patients did not develop argyria until doses five 
times higher were administered. This study and an inhalation 
biomonitoring study by Pillsbury, et al, clearly determined the 
endpoint of concern for humans. Interestingly, the skin form of argyria 
has not been reported in laboratory animals when doses that are 
approximately 4 orders of magnitude higher (100 mg/kg) are 
administered.
    Further support for not requiring additional laboratory animal 
studies for silver is provided from the results of the developmental 
toxicity study in rats, conducted by the National Toxicology Program 
(NTP). In a developmental study conducted in 2002, silver acetate was 
administered by gavage on days 6 - 19 of gestation. No developmental 
effects were reported at doses up to 100 mg/kg; maternal animals were 
observed to have piloerection and rooting behavior at 30 mg/kg. The 
observed effects in maternal animals would not be expected to occur in 
humans and are frequently observed in animal studies. These 
observations, when made in the absence of other clinical findings are 
not considered adverse when establishing a ``no adverse effect level.'' 
More importantly, the results from this study did not demonstrate an 
increased susceptibility of offspring, nor did it demonstrate systemic 
toxicity. This study corroborates the use of the information provided 
by the human biomonitoring study in determining dietary limits for 
silver and further supports our decision to not rely on animal data 
when assessing the health effects of silver in humans.
    In addition to the information gleaned from the biomonitoring 
studies and the developmental toxicity study, the reviews of the 
literature by other EPA offices and national and inter-national 
organizations provide supplemental support that argyria is the primary 
effect in humans (e.g. EPA's Integrated Risk Management System, Agency 
for Toxic Substances and Disease Registry, the World Health 
Organization). Also the acute oral toxicity studies that have been 
provided to support the registration of silver as an antimicrobial 
agent establish LD<INF>50s</INF> between 2,000 and 5,000 mg/kg. These 
values are above the limit dose for acute toxicity. For other silver 
salts, such as silver cyanide, the LD<INF>50</INF> values may be 
significantly lower based on the molecules to which the silver ions are 
attached. For the antimicrobial silver covered by this exemption, the 
LD<INF>50</INF> ranges are very high because the silver ions have very 
low acute toxicity.
    Finally, the pharmacokinetics of silver is understood and may 
explain the low systemic toxicity potential of the compound. 
Pharmacokinetics describes what the body does to a chemical when it is 
introduced into the body including how it is metabolized, distributed, 
and eliminated. When silver is introduced into the body by the oral or 
dietary route, it is absorbed by the digestive system and then enters 
the liver before it reaches the rest of the body (referred to as first-
pass metabolism). This first pass through the liver greatly reduces the 
bioavailability of silver in that about 90% of the orally administered 
dose is eliminated in the feces. The remaining 10% that is not 
eliminated in the feces, reacts with proteins by binding to a specific 
chemical group contained in the structure of the protein. By forming 
silver-protein complexes through this binding action, the remaining 
silver is removed from circulation. This remaining fraction accounts 
for the background levels of silver that are found within the body. At 
excessive doses, the pathways of elimination become saturated and 
deposition of these complexes in the tissues is increased. The 
formation of these complexes and deposition in the skin, mucous 
membranes, and conjunctiva is the primary mechanism which results in 
the development of argyria. Based on information from biomonitoring 
studies, the lowest observed effect level for the formation of argyria 
was 1 gram (total dose), which was converted to an oral dose of 0.014 
mg/kg/day.

B. Regulatory Levels

    Safe exposure levels for silver have been established by several 
regulatory Agencies including the Food and Drug Administration, 
Occupational Safety and Health Administration and other offices within 
EPA based on the common endpoint argyria and using the same human 
studies. Argyria is a blue-gray discoloration of the skin and is not 
considered as being of toxicological concern. Argyria is cosmetically 
disfiguring and permanent in nature; however, the occurrence of this 
condition does not adversely affect organ function or threaten human 
health. EPA believes that by regulating for argyria, it is protecting 
the public from this permanent cosmetic effect as well as any potential 
toxic manifestations of silver that may occur at much higher doses. 
There is no animal condition that would mimic the dermatologic form of 
argyria found in humans following exposure to silver by various routes. 
This may be due in part to the protection imparted by the presence of 
the fur or by the fact that laboratory animal species are not routinely 
exposed to direct sunlight. Argyrosis, a form of argyria which involves 
silver deposition in organs, has been documented. In laboratory 
species, the effects of silver toxicity have been reported to involve 
pathology to the liver (necrosis) and kidney (thickening of the 
basement membranes of the glomeruli), and, at elevated levels, death.
    The effect on which silver is regulated (argyria) occurs only after 
chronic exposure. Both the Secondary Maximum Contamination Level (SMCL) 
reported by the EPA's Office of Water and the oral reference dose (RfD) 
reported under the EPA's Integrated Risk Information System (IRIS) were 
determined based on the previously-mentioned human biomonitoring by 
Gaul and Staud. For the SMCL, additional mathematical derivations were 
applied to the oral equivalent dose

[[Page 27450]]

to the study Lowest Observed Adverse Effect Level (LOAEL) of 0.014 mg/
kg/day to obtain a 0.1 milligram/Liter (mg/L) dose level. The factors 
applied for changing volume to mass account for the slight difference 
in the values reported for the SMCL (0.003 mg/kg/day) and for the RfD 
(0.005 mg/kg/day).
    In deriving the chronic dietary regulatory level (RfD) and the 
SMCL, a safety factor of 3X was applied based on the following 
rationale as reported by the Office of Water and IRIS. First, the 
critical effect was cosmetic and not of toxicological significance. 
Second, the derivation of the LOAEL included the most sensitive 
individual since other patients did not present with argyria unless 
dose levels five times higher were administered. Finally, in the human 
biomonitoring study, silver was administered to these individuals over 
a period of time that is in excess of chronic exposure and that 
approaches a level that would be considered a life time exposure 
duration. Therefore, the dose that was administered was determined as 
being one that would mimic lifetime exposure.
    For the oral exposure route, the Agency is relying on the drinking 
water Secondary Maximum Contaminant Level (SMCL) of 0.1 mg/L (0.003 mg/
kg/day) based on skin discoloration and graying of the whites of eyes 
(argyria). The Agency applied an additional 3X uncertainty factor to 
further address the lack of a NOAEL in the study on which this 
assessment and all regulatory advisories are set. This additional 3X 
factor was not imposed due to the lack or need for additional standard 
animal toxicity testing. Thus, a composite database factor of 10X is 
being applied to account for a lack of NOAEL in the Gaul and Staud 
(1935) study. This composite factor of 10 should be sufficient for 
providing protection from the non-toxic effects which may result from 
chronic oral exposure to silver.

    Chronic Dietary Reference Dose (RFD) = 0.003 mg/kg/day / 3 = 
0.001 mg/kg/day

    Alternatively, a roughly equivalent chronic RfD can be derived by 
dividing the oral equivalent dose from the Gaul and Staud study (0.014 
mg/kg/day) by a factor of 10X.
    Following dermal exposure, silver ions tend to bind to the skin and 
do not penetrate the skin to cause systemic effects. Rather, skin 
discoloration is the only effect induced by silver exposure through the 
dermal route. Although this discoloration appears to be the same effect 
that results from oral and inhalation exposure, the mechanism by which 
discoloration occurs following dermal exposure is not the same as the 
mechanism leading to argyria following other routes of exposure. 
Systemic uptake and distribution of silver following dermal exposure 
does not occur, and the discoloration is the result of a localized 
reaction. Again, the effect is not adverse and there is no reason to 
believe that there would be an increase in susceptibility based on age 
to the nontoxic discoloration. Susceptibility to this cosmetic event is 
a function of dose and not age.

IV. Aggregate Exposures

    To establish a tolerance, it must be shown ``that there is 
reasonable certainty that no harm will result from aggregate exposure 
to pesticide chemical residue, including all anticipated dietary 
exposures and other exposures for which there are reliable 
information.'' Aggregate exposure is the total exposure to a single 
chemical (or its residues) that may occur from dietary (i.e., food and 
drinking water), residential, and other non-occupational sources, and 
from all known or plausible exposure routes (oral, dermal, and 
inhalation).
    Silver is commonly used for a variety of non-pesticidal industrial 
uses, which include but are not limited to photography, cosmetics, 
sunscreens, manufacture of inks and dyes, mirror production, and in 
jewelry. These sources result in primary exposures being via the dermal 
route. As previously mentioned, the consequence of silver exposures via 
the dermal route is dermal argyria, which does not contribute to the 
systemic argyria induced by oral and inhalation routes of exposures. 
Silver has also been used in dentistry (as amalgams) and as an 
ingredient in mouth washes. However, there is no documented evidence of 
argyria developing from dental or mouth wash uses of silver despite its 
widespread and frequent use in dentistry for over a century; 
consequently, EPA concludes that the level of exposure from the dental 
and mouthwash uses is negligible. Therefore, EPA did not aggregate the 
exposures resulting from these various uses with pesticidal exposure 
sources.

A. Dietary Exposure

    Under the current proposal (PP 7F7178), silver will be used as a 
sanitizer for food contact surfaces, resulting in dietary, drinking 
water, and residential exposures. The use sites include but are not 
limited to: Food service facilities, cafeterias, households, kitchens, 
food preparation areas, food processing equipment and treated surfaces, 
such as countertops, equipment, and appliances. The sanitizing solution 
is applied to these various surfaces by spraying (trigger, spraying, 
coarse pump), wiping with a cloth or sponge, mopping, or by full 
immersion. As a result of these uses, residues are expected to transfer 
to the food that comes into contact with these treated surfaces and 
subsequently to be ingested by humans.
    1. Food. The Agency assessed chronic dietary exposure from the use 
of silver as a food contact sanitizer. The dietary assessment was only 
completed for chronic routes because the regulatory effect that has 
been identified is based on argyria, one that occurs only after chronic 
exposure. For dietary exposures from this product being used on 
countertops, the Incidental Dietary Residential Exposure Assessment 
Model, IDREAM<SUP>TM</SUP> incorporates consumption data from USDA's 
Continuing Surveys of Food Intakes by Individuals (CSFII), 1994-1996 
and 1998. The 1994-1996, and 1998 data are based on the reported 
consumption of more than 20,000 individuals over two non-consecutive 
survey days. The maximum rate for silver is 50 ppm active ingredient.
    The use on utensils, dishes and glass was assessed. Based on 
conservative calculations, risk concerns were identified. At this time, 
a label restriction will be required that prohibits the use on 
utensils, dishes and glassware until a residue transfer study has been 
conducted and accepted by the Agency.
    Agricultural Premises-Dairy Facilities. Dietary exposures from 
these general premise uses are expected to be much lower than the 
dietary exposure resulting from the surface disinfectant and sanitizing 
uses considered for this tolerance exemption: therefore, the 
agricultural uses were not assessed separately. However, the 
sanitization of food processing equipment permits product contact with 
the interior of equipment. The milk-truck model (described in the FDA 
document, ``Sanitizing Solutions: Chemistry Guidelines for Food 
Additive Petitions'', pages 9-10)(FDA 2003) for these types of uses was 
executed in order to estimate residues that could transfer from treated 
surfaces to food. From this guidance, it was conservatively assumed 
that a child will consume 320 grams of milk per day (90th percentile 
value) and an adult will consume 125 grams milk per day (mean value). 
Because EPA has utilized this maximized value for children along with a 
child's body weight in this assessment, EPA has confidence that the 
calculations are conservative and representative of any potential risks 
to any population.

[[Page 27451]]

    The Agency assumes that the sanitized tank truck which transports 
the milk is a conservative estimate of residue that is available in 
food processing facilities.
    Milk undergoes no additional dilution prior to reaching the 
consumer and it is also assumed that 100% of the residues available 
post sanitation is transferred to the food.
    Additionally, the dietary contribution as a result of food 
processing equipment sanitization is so extremely small that it is 
considered negligible and not included in the combined or aggregate 
assessments.
    2. Drinking water exposure. There are no outdoor or potable human 
drinking water system uses for the use of silver proposed in pesticide 
petition (PP) 7F7178. In addition, the uses identified as indoor hard 
surface applications will result in minimal, if any, runoff of silver 
into the surface water. The use of silver as a food contact surface 
sanitizer will result in minimal, if any, runoff of silver into the 
surface water. This use will result in an insignificant contribution to 
drinking water exposures. In addition to sanitization, silver is 
registered as an active ingredient in water filters. The bacteriostatic 
water filters are impregnated with silver and may result in residues in 
the drinking water supply. However, the levels of available residues 
resulting from impregnated water filters are much less when in 
comparison to the amount of residues that will be available for intake 
when silver-containing liquid concentrates are used. As a result, any 
drinking water exposures from the new use of silver are assumed to be 
negligible. Additionally, any drinking water risks from impregnated 
filters are assumed to be represented by the dietary risks resulting 
from hard surface sanitization. The Agency believes that an assessment 
of any potential risks resulting from silver in drinking water is not 
warranted at this time.
    Therefore, based on the uses of silver outlined in the pesticide 
petition, the Agency believes that risks resulting from silver in 
drinking water will be negligible and that an assessment is not 
warranted at this time.
    Table 1 provides a comprehensive summary of all of the use patterns 
potentially resulting in dietary exposure that were considered for this 
tolerance exemption.

                    Table 1.--Potential Use Scenarios
------------------------------------------------------------------------
        Use Site Category          Example Use Sites       Scenarios
------------------------------------------------------------------------
Use Site Category I:              Dairy farms, hog    Application to
 Agricultural Premises and         farms, equine       hard surface
 Equipment                         farms               (feeding dishes,
                                                       bottling
                                                       equipment,
                                                       floors, etc)
                                                       through coarse
                                                       spraying (low
                                                       pressure spray),
                                                       trigger pump
                                                       spray, wipe/
                                                       sponge, mop, and
                                                       immersion
------------------------------------------------------------------------
Use Site Categories II, III, and  Food processing     Application to
 V: Food Handling, Commercial/     plants;             hard surfaces
 Institutional/Industrial,         Hospitals; Public   through coarse
 Medical                           places (e.g.,       spraying (low
                                   restaurants,        pressure spray),
                                   hotel/motel         trigger pump
                                   rooms); Medical/    spray, wipe/
                                   Dental offices;     sponge, mop, and
                                   Nursing home;       immersion.
                                   Schools, Cruise    Some examples of
                                   ships, Dining       surfaces include:
                                   Halls.              sinks, cutting
                                                       boards, counter
                                                       tops, kitchen
                                                       appliances,
                                                       breast pumps and
                                                       parts, baby
                                                       bottles, ice
                                                       chests, and
                                                       various others
                                                       that are
                                                       summarized on the
                                                       proposed label.
------------------------------------------------------------------------
Use Site Category IV:             Homes, kitchens     Application to
 Residential and Public Access                         hard surfaces
 Premises                                              through coarse
                                                       spraying (low
                                                       pressure spray),
                                                       trigger pump
                                                       spray, wipe/
                                                       sponge, mop, and
                                                       immersion.
                                                      Examples of the
                                                       hard surfaces
                                                       include those
                                                       identified for
                                                       Use Site
                                                       Categories II,
                                                       III, and V.
------------------------------------------------------------------------

B. Other Non-Occupational Exposure

    The residential exposure assessment considers all potential non-
occupational pesticide exposure, other than exposure due to residues in 
food or in drinking water. Exposures may occur during and after 
application on hard surfaces (e.g., floors). Each route of exposure 
(incidental oral, dermal, inhalation) is considered where appropriate. 
The risks to handlers are quantitatively assessed based on the nature 
of the chemical. As previously stated, there are no adverse 
toxicological consequences (systemic or irritation) resulting from 
contact with silver other than skin discoloration. Residential 
exposures are short-term (< 30 days) and intermediate-term (1 to 6 
months) in nature. As supported in the toxicological discussion, 
however, silver ion produces only cosmetic effects and only as a result 
of chronic exposures. In addition, incidental ingestion (hand to mouth 
behavior of a child on a treated floor) as well as dermal exposures 
resulting from a child contacting a freshly cleaned floor are 
considered short-term in duration.
    Based on the fact that silver will exist in the ionic form, which 
does not volatilize, any post-application inhalation exposures to 
vapors are expected to be negligible. Essentially, there are no 
toxicological consequences (systematic or irritation) resulting from 
contact with silver other than discoloration. Table 2 outlines the use 
patterns and routes of exposure that were considered for purposes of a 
non dietary residential assessment. The Agency will request that label 
claim be placed on the label to advise users that prolonged contact 
with the product may cause skin discoloration.
    Other non-pesticidal industrial uses of silver include, but are not 
limited to, photography, cosmetics, sunscreens, manufacture of inks and 
dyes, mirror production, and in jewelry. All these uses may result in 
exposures via the dermal route, which over a chronic duration, may 
cause skin discoloration. However, dermal exposures resulting from 
these uses are not appropriate to include in this aggregate exposure 
assessment. It has been previously concluded that systemic uptake and 
distribution of silver does not occur via the dermal route. The 
specific uses of silver that were considered for this aggregate 
assessment include the cleansing of hard surfaces in various food 
handling, institutional, medical and residential premises. Exposures

[[Page 27452]]

resulting from freshly cleaned surfaces are considered not to be of 
concern to the Agency.

                       Table 2.--Representative Uses Associated with Residential Exposure
----------------------------------------------------------------------------------------------------------------
          Representative Use              Exposure Scenario        Application Method        Application Rate
----------------------------------------------------------------------------------------------------------------
Indoor Hard Surfaces                   ST Handler: Dermal and   Liquid Pour              4.17 E-04 lb ai/gal
                                        Inhalation;                                      (0.005% ai x 8.34 lb/
                                                                                          gal)
                                      --------------------------------------------------------------------------
                                       ST and IT Post-app\1\:   Mopping                  50 ppm silver ion
                                        child incidental        Wiping.................
                                        ingestion and dermal    Trigger Pump Spray.....
                                                                Low Pressure Spray
                                                                 (coarse spray).
                                                                Immersion\2\...........
----------------------------------------------------------------------------------------------------------------
ST = Short-term exposure, IT = Intermediate-term exposure
\1\ IT post-application exposures to children were assessed because this product could be used in a commercial
  day care facility.
\2\ The handler exposures associated with liquid pouring of this product are representative of those associated
  with immersion (standing solution).

V. Cumulative Effects

    Section 408(b)(2)(D)(v) of FFDCA requires that, when considering 
whether to establish, modify, or revoke a tolerance, the Agency 
consider ``available information'' concerning the cumulative effects of 
a particular pesticide's residues and ``other substances that have a 
common mechanism of toxicity.''
    Unlike other pesticides for which EPA has followed a cumulative 
risk approach based on a common mechanism of toxicity, EPA has not made 
a common mechanism of toxicity finding between silver and any other 
substances and silver does not appear to produce a toxic metabolite 
produced by other substances. For the purposes of this tolerance 
exemption action, therefore, EPA has not assumed that silver has a 
common mechanism of toxicity with other substances. For information 
regarding EPA's efforts to determine which chemicals have a common 
mechanism of toxicity and to evaluate the cumulative effects of such 
chemicals, see the policy statements released by EPA's Office of 
Pesticide Programs concerning common mechanism on EPA's website at 
http://www.epa.gov/pesticides/cumulative.

VI. Safety Factor for Infants and Children-

    1. In general. Section 408(b)(2)(C) of FFDCA provides that EPA 
shall apply an additional tenfold (10X) margin of safety for infants 
and children in the case of threshold effects to account for prenatal 
and postnatal toxicity and the completeness of the database on toxicity 
and exposure unless EPA determines based on reliable data that a 
different margin of safety will be safe for infants and children. This 
additional margin of safety is commonly referred to as the FQPA safety 
factor (SF). In applying this provision, EPA either retains the default 
value of 10X, or uses a different additional safety factor when 
reliable data available to EPA support the choice of a different 
factor.
    2. Prenatal and postnatal sensitivity. There is extensive data and 
analysis on silver's toxicity in the historical data/literature and the 
regulatory advisories established by other Federal Agencies, which do 
not indicate an increased susceptibility of children to the toxic 
effects of silver. A NTP developmental toxicity study concluded that 
the NOAEL recorded for developmental toxicity in rats receiving gavage 
doses of silver acetate, was greater than 100 mg/kg when the test 
material was administered on gestation days 6 through 19. No increase 
in susceptibility was apparent in this study. Furthermore, silver 
nitrate has been used for decades to treat neonatal conjunctivitis. 
Finally, there is no reason to believe that the effects that are 
observed following the administration of silver would warrant 
additional safety factors for children. The skin is the target organ 
and the deposition of silver should not be age dependent. Moreover, 
because EPA believes that the Gaul and Staud study adequately 
characterizes variability in human sensitivity, EPA is not applying an 
intra-species uncertainty factor in deriving the chronic RfD for 
silver.
    3. Conclusion. Although EPA is not applying an inter-species 
uncertainty factor (because of reliance on human data) or an intra-
species uncertainty factor (because human sensitivity has been 
adequately characterized), EPA is retaining the 10X FQPA safety factor 
in assessing oral risk to address the fact that the dose used to 
determine the chronic RfD showed effects from silver (argyria). In 
making this determination, EPA took into account that argyria is not a 
toxic effect, there is no evidence of increased sensitivity in the 
young, and the exposure assessment for silver is very conservative.
    For dermal exposure, silver ions tend to bind to the skin and do 
not penetrate the skin to cause systemic effects. Thus, systemic uptake 
and distribution of silver does not occur following dermal exposure. 
Skin discoloration is the only effect due to a localized reaction. 
Based on the above findings, a FQPA safety factor of 1X should be 
applied to the chronic dietary RfD for assessing dermal exposure. An 
additional safety factor is not required for the protection of infants 
and children because there would not be an increase in susceptibility 
to this cosmetic nontoxic effect. This cosmetic event is a function of 
the dermal contact dose not age. Furthermore, the approach taken to 
assess risk from dermal exposure is very conservative in that the 
Agency has based its dermal risk assessment on the systemic oral dose 
that was used to establish the oral/dietary risks.

VII. Aggregate Risks and Determination of Safety

    Safety is assessed for acute and chronic risks by comparing 
aggregate exposure to the pesticide to the acute population adjusted 
dose (aPAD) and chronic population adjusted dose (cPAD). The aPAD and 
cPAD are calculated by dividing the LOC by all applicable uncertainty/
safety factors. For linear cancer risks, EPA calculates the probability 
of additional cancer cases given aggregate exposure. Short-term, 
intermediate-term, and long-term risks are evaluated by comparing 
aggregate exposure to the LOC to ensure that the margin of exposure 
(MOE) called for by the product of all applicable uncertainty/safety 
factors is not exceeded.
    For a tolerance to be found to be safe, it must be shown ``that 
there is reasonable certainty that no harm will

[[Page 27453]]

result from aggregate exposure to pesticide chemical residue, including 
all anticipated dietary exposures and other exposures for which there 
are reliable information.'' Aggregate exposure is the total exposure to 
a single chemical (or its residues) that may occur from dietary (i.e., 
food and drinking water), residential, and other non-occupational 
sources, and from all known or plausible exposure routes (oral, dermal, 
and inhalation).
    1. Dietary risk. A summary of antimicrobial indirect food use 
acute/chronic risk estimates from exposure to treated countertops are 
shown below in Table 3. As explained above, EPA believes that exposures 
resulting from silver in drinking water will be negligible. For adults, 
chronic dietary exposure risk estimates are approximately 20% of the 
chronic PAD. For children, the most highly exposed population subgroup, 
the chronic dietary risk estimates are 62% of the chronic PAD. 
Therefore, chronic dietary exposure estimates are below the Agency's 
level of concern for all population subgroups.

      Table 3.--Calculated Exposure and risk Resulting from Silver
                       Sanitization of Countertops
------------------------------------------------------------------------
                                                          Chronic
                                                 -----------------------
                 Exposure Group                    DDD(mg/kg/
                                                     d) \a\    %cPAD \b\
------------------------------------------------------------------------
Adult males (13+)                                     0.00022         22
------------------------------------------------------------------------
Adult females (13-69)                                 0.00021         21
------------------------------------------------------------------------
Children (1-2)                                        0.00062         62
------------------------------------------------------------------------
\a\ DDD (mg/kg/day) was provided from the IDREAM model.
\b\ % PAD = exposure (total dietary exposure)/ PAD) x 100. The cPAD is
  equivalent to the chronic oral RfD value of 0.001mg/kg/day.

    2. Aggregate non-cancer risk. Aggregate exposure takes into account 
residential exposure plus chronic exposure to food and water 
(considered to be a background exposure level). Because any oral 
residential exposures will be short-term in nature, the chronic risk is 
equal to the estimate for dietary risk.
    3. Aggregate cancer risk for U.S. population. Available animal and 
human experience through occupational and medicinal exposure scenarios 
have not indicated a carcinogenic potential for silver. Therefore, 
silver is not expected to be carcinogenic to humans particularly in 
light of its low systemic toxicity potential and our understanding of 
its metabolism.
    4. Determination of safety. Based on these risk assessments, EPA 
concludes that there is reasonable certainty that no harm will result 
to the general population or to infants and children from aggregate 
exposure to silver residues.

VIII. Other Considerations

A. Analytical Enforcement Methodology

    An analytical method for food is not needed. Food contact 
sanitizers are typically regulated by state health departments to 
ensure that the food industry is using these products in compliance 
with the regulations in 40 CFR 180.940. The end use solution that is 
applied to the food contact surface is analyzed rather than food items 
that may come into contact with the treated surface. An analytical 
method is available to analyze the use dilution that is applied to food 
contact surfaces. The following methods of analysis are used to analyze 
the use dilution of silver being applied to food contact surfaces: Gas 
chromatography (GC), infrared (IR), ultraviolet absorption (UV), 
nuclear magnetic resonance (NMR).

B. International Residue Limits

    There is not a Codex Maximum Residue Level established for silver.

IX. Statutory and Executive Order Reviews

    This final rule establishes a tolerance under section 408(d) of 
FFDCA in response to a petition submitted to the Agency. The Office of 
Management and Budget (OMB) has exempted these types of actions from 
review under Executive Order 12866, entitled Regulatory Planning and 
Review (58 FR 51735, October 4, 1993). Because this rule has been 
exempted from review under Executive Order 12866, this rule is not 
subject to Executive Order 13211, Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use (66 FR 28355, 
May 22, 2001) or Executive Order 13045, entitled Protection of Children 
from Environmental Health Risks and Safety Risks (62 FR 19885, April 
23, 1997). This final rule does not contain any information collections 
subject to OMB approval under the Paperwork Reduction Act (PRA), 44 
U.S.C. 3501 et seq., nor does it require any special considerations 
under Executive Order 12898, entitled Federal Actions to Address 
Environmental Justice in Minority Populations and Low-Income 
Populations (59 FR 7629, February 16, 1994).
    Since tolerances and exemptions that are established on the basis 
of a petition under section 408(d) of FFDCA, such as the tolerance in 
this final rule, do not require the issuance of a proposed rule, the 
requirements of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et 
seq.) do not apply.
    This final rule directly regulates growers, food processors, food 
handlers and food retailers, not States or tribes, nor does this action 
alter the relationships or distribution of power and responsibilities 
established by Congress in the preemption provisions of section 
408(n)(4) of FFDCA. As such, the Agency has determined that this action 
will not have a substantial direct effect on States or tribal 
governments, on the relationship between the national government and 
the States or tribal governments, or on the distribution of power and 
responsibilities among the various levels of government or between the 
Federal Government and Indian tribes. Thus, the Agency has determined 
that Executive Order 13132, entitled Federalism (64 FR 43255, August 
10, 1999) and Executive Order 13175, entitled Consultation and 
Coordination with Indian Tribal Governments (65 FR 67249, November 6, 
2000) do not apply to this rule. In addition, This rule does not impose 
any enforceable duty or contain any unfunded mandate as described under 
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA) (Public Law 
104-4).
    This action does not involve any technical standards that would 
require Agency consideration of voluntary consensus standards pursuant 
to section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272 
note).

X. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report to each House of the Congress and to 
the Comptroller General of the United States. EPA will submit a report 
containing this rule and other required information to the U.S. Senate, 
the U.S. House of Representatives, and the Comptroller General of the 
United States prior to publication of this final rule in the Federal 
Register. This final rule is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects in 40 CFR Part 180

    Environmental protection, Administrative practice and procedure, 
Food contact sanitizers, Silver, Food additives, Pesticides and pests,

[[Page 27454]]

Reporting and recordkeeping requirements.


    Dated: May 26, 2009.
Joan Harrigan-Farrelly,
Director, Antimicrobials Division, Office of Pesticide Programs.


0
Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

0
 1. The authority citation for part 180 continues to read as follows:

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

0
2. Section 180.940 is amended by adding alphabetically the following 
entry to the table in paragraph (a):


Sec.  180.940   Tolerance exemptions for active and inert ingredients 
for use in antimicrobial formulations (Food-contact surface sanitizing 
solutions).

* * * * *
    (a) * * *

------------------------------------------------------------------------
       Pesticide Chemical            CAS Reg. No.           Limits
------------------------------------------------------------------------
                              * * * * * * *
 Silver ions resulting from the   14701-21-4          When ready for
 use of electrolytically-                              use, the end-use
 generated silver ions                                 concentration of
 stabilized in citric acid as                          silver ions is
 silver dihydrogen citrate (does                       not to exceed 50
 not include metallic silver)                          ppm of active
                                                       silver.
                              * * * * * * *
------------------------------------------------------------------------

* * * * *

[FR Doc. E9-13476 Filed 6-9-09; 8:45 am]
BILLING CODE 6560-50-S


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