[Federal Register Volume 79, Number 204 (Wednesday, October 22, 2014)]
[Proposed Rules]
[Pages 63258-63286]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-24347]



[[Page 63257]]

Vol. 79

Wednesday,

No. 204

October 22, 2014

Part III





 Environmental Protection Agency





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40 CFR Parts 403 and 441





 Effluent Limitations Guidelines and Standards for the Dental Category; 
Proposed Rule

Federal Register / Vol. 79 , No. 204 / Wednesday, October 22, 2014 / 
Proposed Rules

[[Page 63258]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 403 and 441

[EPA-HQ-OW-2014-0693; FRL-9911-63-OW]
RIN 2040-AF26


Effluent Limitations Guidelines and Standards for the Dental 
Category

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing technology-based pretreatment standards under 
the Clean Water Act (CWA) for discharges of pollutants into publicly 
owned treatment works (POTWs) from existing and new dental practices 
that discharge dental amalgam. Dental amalgam contains mercury in a 
highly concentrated form that is relatively easy to collect and 
recycle. Dental offices are the main source of mercury discharges to 
POTWs. Mercury is a persistent and bioaccumulative pollutant in the 
environment with well-documented neurotoxic effects on humans. Mercury 
pollution is widespread and comes from many diverse sources such as air 
deposition from municipal and industrial incinerators and combustion of 
fossil fuels. Mercury easily becomes diffuse in the environment and 
mercury pollution is a global problem. Removing mercury from the waste 
stream when it is in a concentrated and easy to handle form like in 
waste dental amalgam is an important and commonsense step to take to 
prevent that mercury from being released back into the environment 
where it can become diffuse and a hazard to humans.
    The proposal would require dental practices to comply with 
requirements for controlling the discharge of mercury and other metals 
in dental amalgam into POTWs based on the best available technology or 
best available demonstrated control technology. Specifically, the 
requirements would be based on the use of amalgam separators and best 
management practices (BMPs). Amalgam separators are a practical, 
affordable and readily available technology for capturing mercury and 
other metals before they are discharged into sewers and POTWs. EPA is 
also proposing to amend selected parts of the General Pretreatment 
Regulations to streamline oversight requirements for the dental sector. 
EPA expects compliance with this proposed rule would reduce the 
discharge of metals to POTWs by at least 8.8 tons per year, about half 
of which is mercury. EPA estimates the annual cost of the proposed rule 
would be $44 to $49 million.

DATES: Comments on this proposed rule must be received on or before 
December 22, 2014. Under the Paperwork Reduction Act (PRA), comments on 
the information collection provisions must be received by the Office of 
Management and Budget (OMB) on or before November 21, 2014. EPA will 
conduct a public hearing on November 10, 2014 at 1 p.m. in the William 
J. Clinton Building--East Room 1153, 1201 Constitution Avenue NW., 
Washington, DC.

ADDRESSES: Submit your comments, identified by docket identification 
(ID) number EPA-HQ-OW-2014-0693 by one of the following methods:
    <bullet> http://www.regulations.gov: Follow the on-line 
instructions for submitting comments.
    <bullet> Email: <a href="/cdn-cgi/l/email-protection#622d354f260d01090716220712034c050d14"><span class="__cf_email__" data-cfemail="410e166c052e222a2435012431206f262e37">[email protected]</span></a>, Attention Docket ID number EPA-
HQ-OW-2014-0693.
    <bullet> Mail: Water Docket, Environmental Protection Agency, Mail 
code: 4203M, 1200 Pennsylvania Ave. NW., Washington, DC 20460. 
Attention Docket ID number EPA-HQ-OW-2014-0693. Please include a total 
of three copies. In addition, please mail a copy of your comments on 
the information collection provisions to the Office of Information and 
Regulatory Affairs, OMB, Attn: Desk Officer for EPA, 725 17th St. NW., 
Washington, DC 20503.
    <bullet> Hand Delivery: Water Docket, EPA Docket Center, EPA West 
Building Room 3334, 1301 Constitution Ave. NW., Washington, DC, 
Attention Docket ID Number EPA-HQ-OW-2014-0693. Such deliveries are 
only accepted during the Docket's normal hours of operation, and 
special arrangements should be made for deliveries of boxed information 
by calling 202-566-2426.
    Instructions: Direct your comments to docket ID number EPA-HQ-OW-
2014-0693. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
http://www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit information that you 
consider to be CBI or otherwise protected through www.regulations.gov 
or email. The http://www.regulations.gov Web site is an ``anonymous 
access'' system, which means EPA will not know your identity or contact 
information unless you provide it in the body of your comment. If you 
send an email comment directly to EPA without going through http://www.regulations.gov your email address will be automatically captured 
and included as part of the comment that is placed in the public docket 
and made available on the Internet. If you submit an electronic 
comment, EPA recommends that you include your name and other contact 
information in the body of your comment and with any disk or CD-ROM you 
submit. If EPA cannot read your comment due to technical difficulties 
and cannot contact you for clarification, EPA may not be able to 
consider your comment. Electronic files should avoid the use of special 
characters, any form of encryption, and be free of any defects or 
viruses.
    Docket: All documents in the docket are listed in the http://www.regulations.gov index. A detailed record index, organized by 
subject, is available on EPA's Web site at http://water.epa.gov/scitech/wastetech/guide/dental/index.cfm. Although listed in the index, 
some information is not publicly available, e.g., CBI or other 
information whose disclosure is restricted by statute. Certain other 
material, such as copyrighted material, will be publicly available only 
in hard copy. Publicly available docket materials are available either 
electronically in http://www.regulations.gov or in hard copy at the 
Water Docket in the EPA Docket Center, EPA/DC, EPA West William 
Jefferson Clinton Bldg., Room 3334, 1301 Constitution Ave. NW., 
Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 
p.m., Monday through Friday, excluding legal holidays. The telephone 
number for the Public Reading Room is 202-566-1744, and the telephone 
number for the Water Docket is 202-566-2426.
    Pretreatment Hearing Information: EPA will conduct a public hearing 
on the proposed pretreatment standards on November 10, 2014 at 1:00 
p.m. in the William Jefferson Clinton Building EPA East Building--East 
Room 1153, 1201 Constitution Avenue NW., Washington, DC. No 
registration is required for this public hearing. During the 
pretreatment hearing, the public will have an opportunity to provide 
oral comment to EPA on the proposed pretreatment standards. EPA will 
not address any issues raised during the hearing at that time but these 
comments will be included in the public record for the rule. For 
security reasons, we request that you bring photo identification with 
you to the meeting. Also, if you let us know in advance of your plans 
to attend, it will expedite the process of

[[Page 63259]]

signing in. Seating will be provided on a first-come, first-served 
basis. Please note that parking is very limited in downtown Washington, 
and use of public transit is recommended. The EPA Headquarters complex 
is located near the Federal Triangle Metro station. Upon exiting the 
Metro station, walk east to 12th Street. On 12th Street, walk south to 
Constitution Avenue. At the corner, turn right onto Constitution Avenue 
and proceed to the EPA East Building entrance.

FOR FURTHER INFORMATION CONTACT: Damon Highsmith, Engineering and 
Analysis Division (4303T), Office of Water, Environmental Protection 
Agency, 1200 Pennsylvania Ave. NW., Washington, DC 20460-0001; 
telephone: 202-566-2504; email: <a href="/cdn-cgi/l/email-protection#85edece2edf6e8ecf1edabe1e4e8eaebc5e0f5e4abe2eaf3"><span class="__cf_email__" data-cfemail="741c1d131c07191d001c5a1015191b1a341104155a131b02">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION: 

Table of Contents

I. Regulated Entities
II. How To Submit Comments
III. Supporting Documentation
IV. Overview
V. Legal Authority
VI. Purpose and Summary of Proposed Rule
VII. Solicitation of Data and Comments
VIII. Background
IX. Description of the Dental Industry
X. Summary of Data Collection
XI. Wastewater Characteristics, Dental Office Configurations, and 
Technology Options
XII. Scope/Applicability
XIII. Subcategorization
XIV. Proposed Regulation
XV. Technology Costs
XVI. Economic Impact Analysis
XVII. Pollutant Reductions to POTWs and Surface Waters
XVIII. Cost Effectiveness
XIX. Environmental Assessment
XX. Non-Water Quality Environmental Impacts Associated With the 
Proposed Technology Basis
XXI. Implementation and Proposed Changes to General Pretreatment 
Regulations in 40 CFR Part 403
XXII. Statutory and Executive Order Reviews

I. Regulated Entities

    Entities potentially regulated by this action include:
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    \1\ See Section XXI for a definition of Control Authority.

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                                                         North American
                                                            Industry
           Category              Example of regulated    Classification
                                        entity           System (NAICS)
                                                              code
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Industry......................  A general dentistry               621210
                                 practice or large
                                 dental facility
                                 where mercury
                                 amalgam is placed or
                                 removed.
States........................  Where they are the                221320
                                 Control Authority
                                 \1\.
Municipalities................  POTWs and other                   221320
                                 municipally owned
                                 facilities that
                                 receive pollutants
                                 from dental offices.
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    This section is not intended to be exhaustive, but rather provides 
a guide for readers regarding entities likely to be regulated by this 
proposed action. Other types of entities that do not meet the above 
criteria could also be regulated. To determine whether your facility 
would be regulated by this proposed action, you should carefully 
examine the applicability criteria listed in Sec.  441.10 and the 
definitions in Sec.  441.20 of this proposed rule and detailed further 
in Section XII of this preamble. If you still have questions regarding 
the proposed applicability of this action to a particular entity, 
consult the person listed under FOR FURTHER INFORMATION CONTACT.

II. How To Submit Comments

    The public may submit comments in written or electronic form. (see 
ADDRESSES). Electronic comments must be identified by the docket ID 
number EPA-HQ-OW-2014-0693 and must be submitted as a WordPerfect, MS 
Word or ASCII text file, avoiding the use of special characters and any 
form of encryption. EPA requests that any graphics included in 
electronic comments also be provided in hard-copy form. EPA also will 
accept comments and data on disks in the aforementioned file formats. 
Electronic comments received on this document may be filed online at 
many Federal Depository Libraries. No CBI should be sent by email.

III. Supporting Documentation

    The proposed rule is supported by a number of documents including:
    <bullet> Technical and Economic Development Document for Proposed 
Effluent Limitations Guidelines and Standards for the Dental Category 
(TEDD), Document No. EPA-821-R-14-006.
    The TEDD summarizes the technical and economic analysis described 
in this document. The TEDD and additional records are available in the 
public record for this proposed rule and on EPA's Web site at http://water.epa.gov/scitech/wastetech/guide/dental/index.cfm. They are 
available in hard copy from the National Service Center for 
Environmental Publications (NSCEP), U.S. EPA/NSCEP, P.O. Box 42419, 
Cincinnati, Ohio 45242-2419, telephone 800-490-9198, http://epa.gov/ncepihom.

IV. Overview

    The preamble describes the terms, acronyms, and abbreviations used 
in this document; the background documents that support these proposed 
regulations; the legal authority for the proposed rules; a summary of 
the options considered for the proposal; background information; and 
the technical and economic methodologies used by the Agency to develop 
these proposed regulations. This preamble also solicits comment and 
data on specific areas of interest.

V. Legal Authority

    EPA is proposing this regulation under the authorities of sections 
101, 301, 304, 306, 307, 308, and 501 of the CWA, 33 U.S.C. 1251, 1311, 
1314, 1316, 1317, 1318, 1342 and 1361 and pursuant to the Pollution 
Prevention Act of 1990, 42 U.S.C. 13101 et seq.

VI. Purpose and Summary of Proposed Rule

    Across the United States, many states and POTWs (also referred to 
as municipal wastewater treatment plants) are working toward the goal 
of reducing discharges of mercury to POTWs. Mercury is a persistent and 
bioaccumulative pollutant with well-documented effects on human health. 
On November 6, 2013, the United States joined the Minamata Convention 
on Mercury, a new multilateral environmental agreement not yet in force 
that addresses specific human activities that are contributing to 
widespread mercury pollution. The agreement identifies dental amalgam 
as a mercury-added product for which certain measures should be taken. 
Specifically, the Convention lists nine

[[Page 63260]]

measures for phasing down the use of mercury in dental amalgam, 
including promoting the use of best environmental practices in dental 
facilities to reduce releases of mercury and mercury compounds to water 
and land. Nations that are parties to the Convention are required to 
implement at least two of the nine measures to address dental amalgam.
    Many studies have been conducted in an attempt to identify the 
sources of mercury entering POTWs. According to the 2002 Mercury Source 
Control and Pollution Prevention Program Final Report (DCN DA00006) 
prepared by the National Association of Clean Water Agencies (NACWA), 
dentists are the main source of mercury discharges to POTWs. A study 
funded by the American Dental Association (ADA) published in 2005 
estimated that 50% of mercury entering POTWs was contributed by dental 
offices (DCN DA00163). Mercury is discharged in the form of dental 
amalgam when dentists remove old amalgam fillings from cavities, and 
from excess amalgam removed when a dentist places a new filling.
    EPA estimates that across the United States 4.4 tons of mercury 
from waste dental amalgam are collectively discharged into POTWs 
annually. Mercury at POTWs frequently partitions to the sludge, the 
solid material that remains after wastewater is treated. Mercury from 
amalgam can then make its way into the environment through the 
incineration, landfilling, or land application of sludge or through 
surface water discharge. Once deposited, certain microorganisms can 
change mercury into methylmercury, a highly toxic form of mercury that 
accumulates in fish, shellfish, and animals that eat fish. Fish and 
shellfish are the main sources of methylmercury exposure to humans.
    Today's proposed pretreatment standards would control mercury 
discharges to POTWs by requiring dentists to reduce their discharge of 
dental amalgam to a level achievable through the use of the best 
available technology (a combination of amalgam separators and the use 
of BMPs. In order to simplify compliance with, and enforcement of, the 
numeric reduction requirements, the proposed rule would allow dentists 
to demonstrate compliance through the proper use of amalgam separators 
rather than through discharge monitoring. Removing concentrated sources 
of mercury waste opportunistically, such as through low-cost amalgam 
separators at dental offices (average annual cost per dental office: 
$700 \2\), is a common sense solution to managing mercury where it is 
most concentrated within the waste stream that would otherwise be 
released to air, land, and water.
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    \2\ This estimate is based on the average annualized cost for 
dentists that do not currently have an amalgam separator. See DCN 
DA00145.
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    Additionally, EPA is proposing to amend selected parts of the 
General Pretreatment Regulations (40 CFR part 403) in order to 
streamline permitting and oversight requirements specific to the dental 
sector. The number of dental offices that would likely be subject to 
national pretreatment standards is approximately ten times the current 
number of Categorical Industrial Users (CIUs). The proposed changes to 
40 CFR part 403 reflect EPA's recognition that the current regulatory 
framework needs to be adjusted for the effective implementation and 
enforcement of these pretreatment requirements affecting the dental 
industry. When categorical pretreatment requirements apply to an 
industry, it creates certain oversight requirements. While other 
industries subject to categorical pretreatment requirements typically 
consist of tens to hundreds of facilities, the dental industry consists 
of approximately 100,000 facilities, making oversight of this large 
number of facilities subject to categorical pretreatment standards much 
more challenging.

VII. Solicitation of Data and Comments

    EPA solicits comments on the proposed rule, including EPA's 
rationale as described in this preamble. EPA seeks comments on issues 
specifically identified in this document as well as any other issues 
that are not specifically addressed in this document. Comments are most 
helpful when accompanied by specific examples and supporting data. 
Specifically, EPA solicits information and data on the following 
topics.
    1. Data demonstrating the effectiveness of polishing, or the use of 
sorbent columns after solids separation, in reducing mercury discharges 
from dental offices.
    2. Data on costs, performance, affordability and availability of 
polishing in combination with amalgam separators.
    3. Ways for dental offices to demonstrate compliance with this 
proposed rule, and how much reporting should be required.
    4. Information on EPA's approach for addressing offices where no 
dental amalgam is applied or removed, and its approach for offices that 
already employ a separator (including cases where the separator was 
installed as a result of a program required by a state or other 
locality and where the separator has a certified removal efficiency 
that is lower than 99.0%).
    5. Information on the frequency of emergency removals at dental 
offices that do not routinely place or remove amalgam.
    6. EPA seeks comment on its approach for addressing offices where 
no dental amalgam is placed or removed except in limited emergency 
circumstances, and its approach for offices that have already installed 
an amalgam separator.
    7. EPA proposes an inspection frequency of at least once per month 
to ensure proper operation and maintenance of the amalgam separator. 
EPA solicits comment on this frequency as well as others, and 
justifications for alternative approaches.
    8. Data on the number of dentists in practices potentially subject 
to this rule that do not place or remove dental amalgam and on the 
number of dentists in practices excluded from the proposed rule such as 
oral pathology, oral and maxillofacial radiology, oral and 
maxillofacial surgery, orthodontics, periodontics, and prosthodontics. 
EPA also solicits comment on its estimate of the number of dentists in 
dental specialties that are not subject to this proposed rule.
    9. Other technologies not discussed in this proposed rule that have 
demonstrated an ability to reduce discharges of mercury from dental 
offices and their associated costs.
    10. Data regarding EPA's analysis of clinics and very large 
facilities.
    11. EPA's proposed revisions to 40 CFR part 403, including 
revisions to create the DIU category, and the means of evaluating 
ongoing compliance for the purposes of maintaining the DIU designation.
    12. Information about mobile facilities used to treat patients. EPA 
seeks information on the number, size, operation and financial 
characteristics of mobile facilities that offer dental treatment.
    13. EPA's estimate of the number of large institutional practices, 
including large facilities operated by the Federal Government, and the 
characteristics (chair size, number of practitioners, currently 
employed mercury reduction approaches, incremental cost of proposed 
requirements) of these facilities.
    14. Additional information on equipment needs and costs for 
starting a dental practice including information on the life of the 
dental equipment.

[[Page 63261]]

    15. Additional information on low revenue dental offices and if 
they could represent baseline closures (see discussion in Section XVI).
    16. Additional information on the location and characteristics of 
low revenue dental offices ((1) single-dentist and/or part-time 
businesses that provide services as a subcontractor on an independent 
fee-for-service basis (2) non-profit groups, or (3) non-viable as for-
profit businesses).
    17. Information on requiring an efficiency that exceeds the ISO 
standard.
    18. The proposal would greatly reduce potential requirements that 
would otherwise apply to control authorities with respect to dental 
dischargers. EPA solicits comments on its estimate of burden and costs 
associated with these reduced requirements. In particular, EPA solicits 
data from control authorities located in municipalities or states where 
similar mandatory dental amalgam reduction programs exist.

VIII. Background

A. Clean Water Act

    Congress passed the Federal Water Pollution Control Act Amendments 
of 1972, also known as the Clean Water Act, to ``restore and maintain 
the chemical, physical, and biological integrity of the Nation's 
waters.'' (33 U.S.C. 1251(a)). The CWA establishes a comprehensive 
program for protecting our nation's waters. Among its core provisions, 
the CWA prohibits the discharge of pollutants from a point source to 
waters of the U.S. except as authorized under the CWA. Under section 
402 of the CWA, EPA authorizes discharges by a National Pollutant 
Discharge Elimination System (NPDES) permit. The CWA also authorizes 
EPA to establish national technology-based effluent limitations 
guidelines and standards (effluent guidelines or ELGs) for discharges 
from different categories of point sources, such as industrial, 
commercial, and public sources.
    Congress recognized that regulating only those sources that 
discharge effluent directly into the nation's waters would not be 
sufficient to achieve the CWA's goals. Consequently, the CWA requires 
EPA to promulgate nationally-applicable pretreatment guidelines and 
standards that restrict pollutant discharges from facilities that 
discharge wastewater indirectly through sewers flowing to POTWs. (see 
CWA sections 304(g), 307(b) and (c), 33 U.S.C. 1314(g), and 1317(b) and 
(c)). National pretreatment standards are established for those 
pollutants in wastewater from indirect dischargers that may pass 
through, interfere with or are otherwise incompatible with POTW 
operations. Generally, pretreatment standards are designed to ensure 
that wastewaters from direct and indirect industrial dischargers are 
subject to similar levels of treatment. In addition, POTWs are required 
to implement local treatment limits applicable to their industrial 
indirect dischargers to satisfy any local requirements. (see 40 CFR 
403.5).
    Direct dischargers must comply with effluent limitations in NPDES 
permits. Indirect dischargers, who discharge through POTWs, must comply 
with pretreatment standards. Technology-based effluent limitations in 
NPDES permits are derived from effluent limitations guidelines (CWA 
sections 301 and 304) and new source performance standards (CWA section 
306) promulgated by EPA, or based on best professional judgment where 
EPA has not promulgated an applicable effluent guideline or new source 
performance standard. Additional limitations based on water quality 
standards (CWA sections 301(b)(1)(C) and 303) may also be included in 
the permit in certain circumstances. The ELGs are established by 
regulation for categories of industrial dischargers and are based on 
the degree of control that can be achieved using various levels of 
pollution control technology.
    EPA promulgates national effluent limitations guidelines and 
standards of performance for major industrial categories for three 
classes of pollutants: (1) Conventional pollutants (total suspended 
solids, oil and grease, biochemical oxygen demand, fecal coliform, and 
pH); (2) toxic pollutants (e.g., toxic metals such as chromium, lead, 
mercury, nickel, and zinc; toxic organic pollutants such as benzene, 
benzo-a-pyrene, phenol, and naphthalene) as specified in CWA section 
307 and; (3) non-conventional pollutants, those pollutants that are 
neither conventional nor toxic (e.g., ammonia-N, formaldehyde, and 
phosphorus).

B. Effluent Guidelines and Standards Program

    Effluent limitations guidelines and standards are technology-based 
regulations that are developed by EPA for a category of dischargers. 
These regulations are based on the performance of control and treatment 
technologies. The legislative history of CWA section 304(b), describes 
the need to achieve progressively higher levels of control through 
research and development of new processes, modifications, replacement 
of obsolete plans and processes, and other improvements in technology, 
taking into account the cost of controls. Congress also directed that 
EPA not consider water quality impacts on individual water bodies as 
the guidelines are developed. See Statement of Senator Muskie (Oct. 4, 
1972), reprinted in Legislative History of the Water Pollution Control 
Act Amendments of 1972, at 170. (U.S. Senate, Committee on Public 
Works, Serial No. 93-1, January 1973.)
    There are standards applicable to direct dischargers (dischargers 
to surface waters), and standards applicable to indirect dischargers 
(discharges to publicly owned treatment works or POTWs). The standards 
relevant to this rulemaking are summarized here.
1. Best Available Technology Economically Achievable (BAT)
    BAT effluent limitations guidelines apply to direct dischargers of 
toxic and nonconventional pollutants. In general, BAT effluent 
limitations guidelines represent the best economically achievable 
performance of facilities in the industrial subcategory or category. 
The factors considered in assessing BAT include the cost of achieving 
BAT effluent reductions, the age of equipment and facilities involved, 
the process employed, potential process changes, and non-water quality 
environmental impacts including energy requirements, and such other 
factors as the Administrator deems appropriate. The Agency has 
considerable discretion in assigning the weight to be accorded these 
factors. An additional statutory factor considered in setting BAT is 
economic achievability. Generally, EPA determines economic 
achievability on the basis of total costs to the industry and the 
effect of compliance with BAT limitations on overall industry and 
subcategory financial conditions. Where existing performance is 
uniformly inadequate, BAT may reflect a higher level of performance 
than is currently being achieved based on technology transferred from a 
different subcategory or category. BAT may be based upon process 
changes or internal controls, even when these technologies are not 
common industry practice.
2. New Source Performance Standards (NSPS)
    NSPS reflect effluent reductions that are achievable based on the 
best available demonstrated control technology. Owners of new 
facilities have the opportunity to install the best and most efficient 
production processes and wastewater treatment technologies.

[[Page 63262]]

As a result, NSPS should represent the most stringent controls 
attainable through the application of the best available demonstrated 
control technology for all pollutants (that is, conventional, 
nonconventional, and priority pollutants). In establishing NSPS, EPA is 
directed to take into consideration the cost of achieving the effluent 
reduction and any non-water quality environmental impacts and energy 
requirements.
3. Pretreatment Standards for Existing Sources (PSES)
    Pretreatment standards apply to discharges of pollutants to POTWs 
rather than discharges to waters of the United States. Pretreatment 
Standards for Existing Sources are designed to prevent the discharge of 
pollutants that pass through, interfere with, or are otherwise 
incompatible with the operation of POTWs, including sludge disposal 
methods of POTWs. Categorical pretreatment standards for existing 
sources are technology-based and are analogous to BAT effluent 
limitations guidelines.
    The General Pretreatment Regulations, which set forth the framework 
for the implementation of categorical pretreatment standards, are found 
at 40 CFR part 403.
4. Pretreatment Standards for New Sources (PSNS)
    Like PSES, PSNS are designed to prevent the discharges of 
pollutants that pass through, interfere with, or are otherwise 
incompatible with the operation of POTWs. New indirect discharges have 
the opportunity to incorporate into their facilities the best available 
demonstrated technologies. The Agency typically considers the same 
factors in promulgating PSNS as it considers in promulgating NSPS.
5. BMPs
    Section 304(e) of the CWA authorizes the Administrator to publish 
regulations, in addition to effluent limitations guidelines and 
standards for certain toxic or hazardous pollutants, ``to control plant 
site runoff, spillage or leaks, sludge or waste disposal, and drainage 
from raw material storage which the Administrator determines are 
associated with or ancillary to the industrial manufacturing or 
treatment process . . . and may contribute significant amounts of such 
pollutants to navigable waters.'' In addition, section 304(g), read in 
concert with section 501(a), authorizes EPA to prescribe as wide a 
range of pretreatment requirements as the Administrator deems 
appropriate in order to control and prevent the discharge into 
navigable waters either directly or through POTWs any pollutant which 
interferes with, passes through, or otherwise is incompatible with such 
treatment works. (see also Citizens Coal Council v. U.S. EPA, 447 F3d 
879, 895-96 (6th Cir. 2006) (upholding EPA's use of non-numeric 
effluent limitations and standards); Waterkeeper Alliance, Inc. v. U.S. 
EPA, 399 F.3d 486, 496-97, 502 (2d Cir. 2005) (EPA use of non-numerical 
effluent limitations in the form of BMPs are effluent limitations under 
the CWA); and Natural Res. Def. Council, Inc. v. EPA, 673 F.2d 400, 403 
(D.C. Cir. 1982) (``section 502(11) [of the CWA] defines `effluent 
limitation' as `any restriction' on the amounts of pollutants 
discharged, not just a numerical restriction.'')

C. The National Pretreatment Program, 40 CFR Part 403

    The General Pretreatment Regulations of 40 CFR part 403 establish 
responsibilities among federal, state, local government, industry, and 
the public to implement pretreatment standards to control pollutants 
that pass through or interfere with the POTW treatment processes or 
that can contaminate sewage sludge. The regulations, which have been 
revised numerous times since originally published in 1978, consist of 
20 sections and seven appendices. The General Pretreatment Regulations 
use two terms describing oversight responsibilities under those 
regulations. One is the term Control Authority. The ``Control 
Authority'' refers to the POTW if the POTW has an approved Pretreatment 
Program, or the Approval Authority if the program has not been 
approved. The term Approval Authority describes the party with 
responsibility to administer the National Pretreatment Program, which 
is either a state with an approved state Pretreatment Program or, in a 
state without an approved Pretreatment Program, the EPA region for that 
state (40 CFR 403.3(f)). An approved Pretreatment Program is comprised 
of legal authorities, procedures, funding, local limits, enforcement 
response plan, and the list of significant industrial users (SIUs), 
together which the Control Authority uses to implement the General 
Pretreatment Regulations. The General Pretreatment Regulations apply to 
all nondomestic sources that introduce pollutants into a POTW. These 
sources of indirect discharges are more commonly referred to as 
Industrial Users (IUs). All IUs are subject to general pretreatment 
standards (40 CFR part 403), including a prohibition on discharges 
causing ``pass through'' or ``interference'' (i.e., cause the POTW to 
violate its permits limits, or interfere with the operation of the POTW 
or the beneficial use of its sewage sludge). All POTWs with approved 
Pretreatment Programs must develop local limits to implement the 
general pretreatment standards. All other POTWs must develop such local 
limits where they have experienced ``pass through'' or ``interference'' 
and such a violation is likely to recur. There are approximately 1,500 
POTWs with approved Pretreatment Programs and 13,500 small POTWs that 
are not required to develop and implement Pretreatment Programs.

D. State and Local Requirements

    Currently, 12 states (Connecticut, Louisiana, Maine, Massachusetts, 
Michigan, New Hampshire, New Jersey, New York, Oregon, Rhode Island, 
Vermont, and Washington) have implemented mandatory programs to reduce 
dental mercury discharges.\3\ Additionally, at least 19 localities 
similarly have mandatory dental reduction pretreatment programs. These 
mandatory programs require the use of amalgam separators and BMPs. 
Removal efficiency requirements for separators in mandatory program 
jurisdictions vary from 95% to 99%. A full list of jurisdictions with 
mandatory separator requirements can be found in the TEDD for this 
proposed rulemaking.
---------------------------------------------------------------------------

    \3\ New Mexico has a similar program that is scheduled to go 
into effect in 2015.
---------------------------------------------------------------------------

    Later in this document, EPA estimates costs and economic impacts 
for this proposed rule. In order to do so, EPA needed to estimate 
baseline compliance, or those dental offices that already have amalgam 
separators installed, and, therefore, would incur lower costs and 
impacts from the proposed rule. In order to estimate baseline 
compliance, EPA distributed the number of dental offices shown in Table 
IX-1 of Section IX by state,\4\ based on the 2007 Economic Census. 
Because EPA has no data to indicate otherwise, EPA assumes 100% 
compliance in the 12 states that require amalgam separators. For states 
without mandatory programs, EPA assumed that 20% of dentists have 
voluntarily installed amalgam separators. As a result, EPA estimates 
approximately 40% of dental offices, nationally, have amalgam 
separators installed (DCN DA00146). EPA, however, welcomes data and 
comment on this assumption.
---------------------------------------------------------------------------

    \4\ Puerto Rico, the Virgin Islands, Pacific Islands and Tribal 
Nations are not included in this analysis.

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[[Page 63263]]

E. 2008 Memorandum of Understanding on Reducing Mercury Discharges

    In December 2008, EPA signed a Memorandum of Understanding (MOU) 
with the ADA and the NACWA to establish and monitor the effectiveness 
of a Voluntary Dental Amalgam Discharge Reduction Program. The purpose 
of the MOU is to encourage dental offices to voluntarily install and 
properly maintain amalgam separators, and recycle the collected amalgam 
waste. Although EPA has not conducted a formal evaluation of the 
effectiveness of the MOU, EPA is proposing National Pretreatment 
Standards to accomplish the goals of the MOU in a more predictable 
timeframe than a voluntary approach.

F. ADA BMPs and Support for a National Rulemaking

    ADA encourages dentists to handle mercury and mercury amalgam in a 
manner that is consistent with ADA's ``Best Management Practices for 
Amalgam Waste.'' ADA's BMPs are designed to reduce the amount of 
mercury entering the environment. Practices encouraged by these BMPs 
include reducing the volume of bulk elemental mercury in dentists' 
offices, encouraging dentists to recycle amalgam to the greatest extent 
possible, preventing mercury from being disposed of in medical waste 
bags, and preventing amalgam from entering the wastewater stream. In 
2007, ADA added the use of amalgam separators to their BMPs. See DCN 
DA00165.
    In late 2010, ADA's Board of Directors adopted nine principles upon 
which ADA supported National Pretreatment Standards for dental 
facilities. See DCN DA00137.

IX. Description of the Dental Industry

    The industry category that would be affected by this proposed rule 
is Offices of Dentists (NAICS 621210), which comprises establishments 
of health practitioners primarily engaged in the independent practice 
of general or specialized dentistry, or dental surgery. These 
practitioners operate individual or group practices in their own 
offices or in the offices of others, such as hospitals or health 
maintenance organization medical centers. They can provide either 
comprehensive preventive, cosmetic, or emergency care, or specialize in 
a single field of dentistry.
    According to the 2007 Economic Census, there were 127,057 U.S. 
dental offices owned or operated by 121,048 dental firms.\5\ Only 2% of 
all dental firms were multi-unit with the vast majority being single-
unit. The growth of the number of dental offices has remained steady 
over the past decade with an average increase of 1% per year.
---------------------------------------------------------------------------

    \5\ A firm is a business organization, such as a sole 
proprietorship, partnership, or corporation.
---------------------------------------------------------------------------

    The industry includes mostly small businesses with an estimated 
99.8% of all offices falling below the Small Business Administration 
(SBA) size standard ($7 million in annual revenue). Average revenues 
for offices were estimated at $739,280 per year with an average of 6.50 
employees per establishment.
    According to ADA data, approximately 80% of the dental industry 
engages in general dentistry. Approximately 20% are specialty dentists 
such as periodontics, orthodontics, radiology, maxillofacial surgery, 
endodontists, or prosthodontics (DCN DA00123).
    One way to categorize dental offices is based on the number of 
chairs in each facility. The 2007 Economic Census does not provide 
information on the distribution of dental offices by the number of 
chairs in each office. However, two studies, the ADA National Study and 
a Colorado Study, demonstrate distribution of dentist offices by number 
of chairs (DCN DA00141 and DCN DA00149). EPA used these two sources of 
data to correlate the number of chairs per office to the revenue range 
of dental offices. EPA averaged the correlation of these two studies. 
The results are reported in table IX-1:

                            Table IX-1--Number of Dental Offices by Number of Chairs
----------------------------------------------------------------------------------------------------------------
                                                                          Number of offices by chair size
                                                                 -----------------------------------------------
                        Number of chairs                                             Colorado
                                                                    ADA survey        survey          Average
----------------------------------------------------------------------------------------------------------------
1-2 chairs......................................................          13,694          10,700          12,197
3 chairs........................................................          47,698          27,821          25,835
4 chairs........................................................                          32,102          27,976
5 chairs........................................................          29,388          15,694          15,194
6 chairs........................................................                           9,399          12,047
7+ chairs.......................................................          19,079          14,143          16,611
                                                                 -----------------------------------------------
    Total.......................................................         109,859         109,859         109,859
----------------------------------------------------------------------------------------------------------------

    Dentistry may also be performed at larger institutional dental 
service facilities (e.g., clinics or dental schools). These facilities 
are not included in the 2007 Economic Census data. EPA estimates 130 
dental institutional facilities exist nationwide. EPA recognizes that 
large facilities also may exist at installations operated by the 
Federal Government, specifically the Department of Defense. While EPA 
intends such facilities would be subject to today's proposed rule, EPA 
does not have information to estimate the number of such facilities.
    EPA currently lacks a central database on reported discharges from 
dental offices/clinics. Often, EPA looks to information in the Toxic 
Release Inventory (TRI) and Discharge Monitoring Report (DMR) databases 
to gather information on industrial discharges. However, no dental 
offices/clinics (NAICS Code 621210) are required to report releases to 
TRI. EPA identified only five dental offices that have National 
Pollutant Discharge Elimination System (NPDES) permit information. All 
dental offices were classified as minor dischargers. EPA has not found 
any DMR data indicating that any significant number of dental offices 
discharge directly to waters of the U.S. Therefore, EPA is not 
proposing effluent limits for direct dischargers.\6\
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    \6\ EPA recognizes that some dental facilities may discharge to 
a septic system. This proposed rule does not apply to such 
discharges.

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[[Page 63264]]

X. Summary of Data Collection

    In developing this proposed rule, EPA primarily used data 
previously collected for its Health Services Detailed Study including 
information submitted in public comments on the study. EPA also 
collected information and data through outreach to a number of 
stakeholders. The following describes EPA's outreach and additional 
data sources for this proposed rule.

A. Health Services Industry Detailed Study on Dental Amalgam

    In 2008, EPA published its Health Services Industry Detailed Study 
on Dental Amalgam. In the study, EPA compiled information on mercury 
discharges from dental offices, BMPs, and amalgam separators. For 
amalgam separators, EPA examined the frequency with which they were 
used; their effectiveness in reducing discharges to POTWs; and the 
capital and annual costs associated with their installation and 
operation. EPA also conducted a POTW pass-through analysis on mercury 
for the industry. This proposed rule relies heavily on data collected 
for the study (including information submitted in public comments on 
the study).

B. Environmental Council of the States (ECOS)

    EPA participated in several meetings with the Quicksilver Caucus 
(QSC) of ECOS. From QSC, EPA collected information on implementing 
mandatory amalgam separator programs at the state level, mandatory 
program language, and information on compliance reporting and 
monitoring. QSC also provided EPA with information on efficiency 
standards for amalgam separators. See DCN DA00158.

C. Environmental Organizations

    EPA met with a coalition of environmental organizations, led by the 
Environmental Law and Policy Center and the Natural Resources Defense 
Council. Meetings between EPA and the coalition of environmental 
organizations focused on identifying impacts of discharges of dental 
amalgam to the environment. In Spring 2011, the coalition submitted a 
letter listing its suggested BMPs for this proposed rule. See DCN 
DA00136.

D. ADA

    EPA met with the ADA in 2010 and 2011. ADA submitted data to EPA on 
its principles for addressing mercury discharges from dentists, the 
proportions of specialties in the industry, the geographic distribution 
of dentists, financial characteristics of the industry, and operating 
characteristics of the industry. See DCN DA00137.

E. NACWA

    EPA met with NACWA in 2010 and 2011 to discuss the impact of 
pretreatment standards on POTWs. NACWA provided EPA information on its 
members' experiences with handling mercury pollution from dental 
facilities, implementing pretreatment programs for dental facilities, 
and its experiences implementing pretreatment standards for industries 
with similar characteristics to the dental sector. NACWA also provided 
EPA with information on the burden to permitting authorities that would 
be associated with implementing a dental amalgam pretreatment standard 
under the existing requirements in 40 CFR part 403. See DCN DA00144.

F. Amalgam Separator Manufacturers

    EPA met with, or participated in calls with, representatives of 
multiple amalgam separator manufacturers. The purpose of the meetings 
was to understand how amalgam separators work, limitations of the 
technology, manufacturers' distribution methods, installation 
requirements, capital and operation and maintenance costs, operation 
and maintenance requirements, effectiveness, equipment lifetime, 
amalgam disposal or recycling practices, manufacturing capacity, and 
installation trends.

G. Air Force Study

    In anticipation of this proposed rule, the United States Air 
Force's Dental Evaluation and Consultation Service compiled a synopsis 
of commonly used amalgam separator systems. The synopsis describes 
whether or not the separator is International Organization for 
Standardization (ISO) 11143 certified, the installation requirements, 
the design capacity, maintenance requirements for each model, the 
availability of recycling services by the manufacturer, size, price, 
and warranty details. EPA incorporated these data into the technology 
cost analysis. The synopsis can be found in the TEDD for this proposed 
rule.

XI. Wastewater Characteristics, Dental Office Configurations, and 
Technology Options

A. Wastewater Sources and Wastewater Characteristics

    Dental amalgam consists of approximately 49% mercury by weight. 
Mercury is the only metal that is in its liquid phase at room 
temperature, and it bonds well with powdered alloy. This contributes to 
its durability in dental amalgam. The other half of dental amalgam is 
usually composed of 35% silver, 9% tin, 6% copper, 1% zinc and small 
amounts of indium and palladium (DCN DA00131). Sources of mercury 
discharges generally occur in the course of two categories of 
activities. The first category of discharges may occur in the course of 
treating a patient, such as during the placement or removal of a 
filling. When filling a cavity, dentists overfill the tooth cavity so 
that the filling can be carved to the proper shape. The excess amalgam 
is typically rinsed into a chair-side drain, or suctioned out of the 
patient's mouth. In addition to filling new cavities, dentists also 
remove old cavity restorations that are worn or damaged. Removed 
restorations also may be rinsed into the chair-side drain or suctioned 
out of the patient's mouth. The second category of mercury discharges 
occur in the course of activities not directly involved with the 
placement or removal of dental amalgam. Preparation of dental amalgam, 
disposing of excess amalgam, and flushing vacuum lines with corrosive 
chemicals present opportunities for mercury from dental amalgam to be 
discharged.

B. Dental Office Configurations

    The typical plumbing configuration in a dental office consists of a 
chair-side trap for each chair, and a central vacuum pump with a vacuum 
pump filter. Chair-side traps and vacuum pump filters remove 
approximately 78% of dental amalgam particles from the wastewater 
stream (DCN DA00163). Offices with multiple chairs typically share the 
vacuum lines between chairs. Accordingly, this limits the locations for 
installation of control and treatment technologies. Controls may be 
installed: At or near each individual chair; within the vacuum system 
piping; at a central location upstream of the vacuum pump; or at the 
exit of the air/water separator portion of the vacuum system. Physical 
office and building configurations may pose additional considerations, 
such as space limitations, electrical power accessibility, and existing 
sewer connections. In the case of very large offices, clinics, and 
medical buildings, it may be possible to combine waste flows between 
offices to share or reduce costs.

C. Control and Treatment Technologies and Best Management Practices

    As described previously, one source of the discharge of mercury 
from dental amalgam occurs when dental amalgam enters the chair-side 
drain, or is suctioned from the patient's mouth. The wastewater then 
travels through the dental facility's vacuum system. EPA

[[Page 63265]]

identified two major technologies that intercept dental amalgam at this 
point, before it is discharged from the dental office and flows to the 
POTW: Separators and ion exchange. EPA also identified several BMPs 
which, when employed along with the use of the technologies discussed 
below, further reduce the discharge of dental amalgam from activities 
not directly related to the placement or removal of dental amalgam.
1. Amalgam Separators
    An amalgam separator is a device designed to remove solids from 
dental office wastewater. The amalgam separator is placed at some point 
in the vacuum line, before the vacuum line intersects with plumbing in 
other parts of the building, and separates solids from wastewater. Most 
separator designs rely on the force of the dental facility's vacuum to 
draw wastewater into the separator. However, the separation of solids 
from the wastewater and the exit of the wastewater from the separator 
will vary by design of the separator.
    Practically all amalgam separators on the market today use 
sedimentation processes. The high specific gravity of amalgam allows 
effective separation of amalgam from suspension in wastewater. Baffles 
or tanks can reduce the speed of the wastewater flow, allowing more 
amalgam particles to settle out. After the solids settle, the 
wastewater is either pumped out, decanted during servicing, or is 
pulled through the separator. Sedimentation-based separators are often 
used over other separation technologies for their operational 
simplicity.
    Some amalgam separators may combine filtration with separation. 
Different types of filtration units can be employed to remove 
additional amalgam particles. The amalgam separator may also be 
designed to operate horizontally where wastewater is drawn into one 
side of the separator, filtered, and then exits the opposite side of 
the separator. This type of separator is designed to be completely 
replaced once it reaches its design solids holding capacity. In 
addition to combined separation and filtration units, EPA is aware of 
at least one type of separator that utilizes centrifugation. A 
centrifuge-based separator spins the water so that the heavier amalgam 
particles are forced to the sides of the separator.
    A few amalgam separators combine sedimentation (with or without 
filtration) with ion exchange in the same unit. This type of separator 
additionally includes a chelating agent or proprietary resin. This type 
of separator often requires special cleaning or additives to maintain 
efficiency.
    The typical amalgam separator will operate in one of two ways. A 
two-chambered separator is a design consisting of a base permanently 
plumbed into the vacuum line, and a replaceable filtration cartridge. 
The removable cartridge usually attaches to the bottom of the permanent 
base. As wastewater enters the separator from the top of the unit, 
gravity separates the wastewater from the air pulling it through the 
vacuum. Air from the vacuum continues through the system by exiting a 
bypass at or near the top of the base chamber. Wastewater then falls 
through the base of the separator and enters the filtration cartridge. 
As additional wastewater enters the separator, the filtration cartridge 
will fill to capacity, and wastewater will begin to collect at the 
bottom of the base chamber. Gravity forces wastewater in the separator 
through a filtration device and out of the separator through a 
decanting tube on the side of the separator. The wastewater, less the 
solids retained by the separator, then continues through the vacuum 
system and is eventually discharged from the dental office and to the 
sanitary sewer and the POTW. The second common separator design 
consists of a single chamber that requires wastewater to travel through 
a filtration medium before it is drawn out of the separator. These 
separators may be oriented vertically so that wastewater enters the top 
of the unit, remains in the separator for some time, and allows solids 
to settle. For either design, when the filtration cartridge or the 
separator itself reaches the designed solids retention capacity, it 
must be replaced. Manufacturers can include replacement schedules and 
capacity levels for amalgam separators.
    The vast majority of amalgam separators on the market today have 
been evaluated for their ability to meet the International Organization 
for Standardization Standard for Dental Amalgam Separators (http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=42288). This voluntary standard setting 
organization established a standard for measuring amalgam separator 
efficiency by evaluating the retention of amalgam mercury using 
specified test procedures in a laboratory setting. It also includes 
requirements for instructions for use and operation and maintenance. In 
order to obtain the ISO certification, a separator must achieve 95% 
removal or greater of total mercury. Based on EPA's evaluation of a 
range of amalgam separators as described above that meet the ISO 
standard and that are currently on the market, certified separators 
obtain a median of 99.0% total mercury removal efficiency (see Section 
7 of the TEDD). When existing chair side traps and vacuum pump filters 
are used upstream of the amalgam separators, the combined treatment 
system can achieve total mercury removal rates exceeding 99% (DCN 
DA00008).
    EPA is proposing to include certain operation, maintenance, and 
inspection activities that have the greatest impact on the ability of 
an amalgam separator to achieve its performance as certified. Once the 
separator reaches solids retention capacity, vacuum suction will begin 
to diminish or, more commonly, the separator will enter bypass mode. 
Wastewater running through a separator in bypass mode flows through the 
separator without being filtered, rendering the separator ineffective. 
Because many separators can enter bypass mode without any noticeable 
effect on vacuum suction, it would be important that the unit be 
checked periodically, and if necessary, serviced.\7\
---------------------------------------------------------------------------

    \7\ There may be separators on the market that do not notify 
users when they are in bypass mode or otherwise require servicing. 
These separators would not meet ISO certification standards.
---------------------------------------------------------------------------

    Solids collected by the amalgam separator may be a combination of 
dental amalgam, biological material from patients, and any other solid 
material sent down the vacuum line. Amalgam separator manufacturer 
instructions should be followed for servicing amalgam separators and 
for handling separator waste. Some amalgam separator manufacturers also 
offer waste management services. Examples of services provided include 
ensuring that waste collected by the separator is handled according to 
state and local requirements, and providing necessary compliance 
documentation for the facility's recordkeeping requirements. In the 
event that these services are not employed, the facility should dispose 
of amalgam waste in accordance with state and local requirements.
    Most amalgam separators are compatible with both wet and dry vacuum 
systems, and with both large and small dental offices.\8\ As explained 
in Section VIII, currently at least 12 states and 19 localities have 
implemented mandatory programs to reduce dental mercury discharges. All 
of these programs require the use of

[[Page 63266]]

amalgam separators. Further, many dental offices in states or 
localities without mandatory programs have voluntarily installed dental 
amalgam separators, and the ADA recommends their use as part of its 
``Best Management Practices for Amalgam Waste'' (2007). As described in 
Section VIII, EPA estimates that 40% of dental offices currently employ 
amalgam separators.
---------------------------------------------------------------------------

    \8\ This does not mean all types of separators are compatible at 
a given dental office. For example, an amalgam separator that relies 
on filtration technology may not be compatible with a dry vacuum 
system in place.
---------------------------------------------------------------------------

2. Polishing To Remove Dissolved Mercury From Wastewater
    Mercury in dental amalgam is present in both the suspended and 
dissolved form. The vast majority (>99.6%) is suspended (DCN DA00018). 
An additional process sometimes referred to as ``polishing'' uses ion 
exchange to remove dissolved mercury. In contrast to amalgam separators 
that contain an ion exchange component in the same unit, as discussed 
in the previous section, ``polishing'' ion exchange refers to a 
separate wastewater treatment system added after the amalgam separator 
for the purpose of removing dissolved mercury.
    Dissolved mercury has a tendency to bind with other chemicals, 
resulting in a charged complex. Ion exchange is the process that 
separates these charged amalgam particles from the wastewater. Ion 
exchange does not rely on physical settling of particles, and can 
remove very small amalgam and ionic mercury particles. This technology 
may be preferable over sedimentation (with or without filtration) alone 
because dissolved mercury is removed by this process. For example, ion 
exchange might be useful in municipalities that have concentration 
limits on mercury (McManus, 2003). EPA is not aware of any state 
regulations that require ion exchange.
    For ion exchange to be most effective, the incoming wastewater to 
be treated must first have the solids removed. Then the wastewater 
needs to be oxidized in order for the resin or mercury capturing 
material to capture the dissolved mercury. Therefore, ion exchange will 
not be effective without first being preceded by a solids collector. As 
a result, EPA concludes this sequential polishing approach, in which 
amalgam separators and ion exchange are separate units, is more 
effective than the single units described above that combine 
sedimentation and ion exchange. Dental offices needing to employ 
polishing would likely need to add a separate ion exchange unit 
following the amalgam separator to remove additional mercury from the 
waste stream.
    As explained above, ISO certification testing is based on an 
evaluation of the removal of total mercury in a laboratory setting and 
does not differentiate removal for the suspended and dissolved 
forms.\9\ In order to better understand the reductions in dissolved 
mercury that can be achieved with the addition of ion exchange as 
polishing, EPA reviewed available data on the performance from actual 
installations of ion exchange units in addition to amalgam separators 
in dental offices. EPA found the use of polishing is limited to just a 
handful of dental offices. EPA identified only one study of polishing 
systems, and has not identified any further data pertaining to the 
performance of polishing. This one study evaluated the additional 
efficacy associated with polishing at two dental facilities in response 
to sanitation district concerns over mercury discharges. In both cases, 
the polishing systems were installed after the amalgam separators but 
prior to discharge into the treatment plant's collection system. While 
a reduction was observed in the final effluent mercury after the 
polishing system was installed, preliminary EPA Region 8 audits showed 
the total additional mercury reductions were typically on the order of 
0.5% (DCN DA00164). This is not surprising since, as indicated above, 
dissolved mercury contributes such a small portion to the total amount 
of mercury in dental amalgam. It is unclear whether any solid mercury 
was converted to dissolved mercury, and additional monitoring data are 
not yet available.
---------------------------------------------------------------------------

    \9\ In some cases, the ISO testing results include ranges of 
dissolved mercury in the effluent.
---------------------------------------------------------------------------

    The capital costs of the polishing system, as a stand-alone system, 
are approximately four times that of the amalgam separator; the costs 
for chemical use, regenerating the resin, filter replacement, and other 
operational costs were not reported. Further, EPA is uncertain whether 
typical dental buildings have adequate space to install the holding 
tanks needed to oxidize the waste before treatment, as well as space 
for the polishing equipment itself.

D. Best Management Practices

    EPA considered what BMPs reflect the best available technology 
economically achievable or best available demonstrated control 
technology--the standards applicable to existing and new sources 
subject to categorical pretreatment standards. After this review, EPA 
proposes to include certain operation, maintenance, and inspection 
practices as part of the technology basis for this proposed rule. These 
practices have the greatest impact on the ability of an amalgam 
separator to achieve its performance as certified.
    EPA also proposes to require two BMPs to control mercury discharges 
that would not be captured by an amalgam separator. Bleach and other 
corrosive cleaners can solubilize bound mercury. If corrosive cleaners 
are used to clean vacuum lines that lead to an amalgam separator, the 
line cleaners may solubilize any mercury that the separator has 
captured, leading to increased mercury discharges. Therefore, EPA 
proposes to require line cleaners that do not contain bleach, and are 
of neutral pH.
    Flushing scrap amalgam (contact and non-contact), including dental 
amalgam from chair-side traps, screens, vacuum pump filters, dental 
tools, or collection devices into drains that do not have a solids 
collecting device presents additional opportunities for mercury to be 
discharged from the dental office. Therefore, EPA proposes to include a 
BMP that prohibits flushing scrap dental amalgam into any drain that is 
not connected to an amalgam separator.

XII. Scope/Applicability

    As mentioned in the previous section, EPA has not identified dental 
offices/clinics discharging directly to waters of the U.S. Because EPA 
has very limited information on any direct discharge of dental amalgam, 
EPA is not proposing effluent limitations guidelines and new source 
performance standards for direct dischargers at this time.
    As such, EPA is proposing to apply this rule to wastewater 
discharges to POTWs from offices where the practice of dentistry is 
performed, including institutions, permanent or temporary offices, 
clinics, mobile units, home offices, and facilities, and including 
dental facilities owned and operated by Federal, state, or local 
governments. EPA is not proposing to include wastewater discharges from 
dental facilities where the practice of dentistry consists exclusively 
of one or more of the following dental specialties: oral pathology, 
oral and maxillofacial radiology, oral and maxillofacial surgery, 
orthodontics, periodontics, or prosthodontics. As described in the 
TEDD, these specialty practices do not engage in the practice of 
restorations or removals, and are not expected to have any discharges 
of dental amalgam.

XIII. Subcategorization

    In developing effluent limitations guidelines and pretreatment 
standards, EPA may divide an industry category into groupings called 
''subcategories'' to

[[Page 63267]]

provide a method for addressing variations among products, processes, 
and other factors, which result in distinctly different effluent 
characteristics. See Texas Oil & Gas Ass'n. v. U.S. EPA, 161 F.3d 923, 
939-40 (5th Cir. 1998). Regulation of a category by subcategories 
provides that each subcategory has a uniform set of effluent 
limitations or pretreatment standards that take into account 
technological achievability, economic impacts, and non-water quality 
environmental impacts unique to that subcategory. In some cases, 
effluent limitations or pretreatment standards within a subcategory may 
be different based on consideration of these same factors, which are 
identified in CWA section 304(b)(2)(B). The CWA requires EPA, in 
developing effluent guidelines and pretreatment standards, to consider 
a number of different factors, which are also relevant for 
subcategorization. The CWA also authorizes EPA to take into account 
other factors that the Administrator deems appropriate.
    In developing the proposed rule, EPA considered whether 
subcategorizing the dental industry was warranted. EPA evaluated a 
number of factors and potential subcategorization approaches, including 
the size of dental office, specialty practices, and unusual 
configurations that may be found at very large offices such as clinics 
and universities. EPA proposes that establishing formal subcategories 
is not appropriate for the Dental Amalgam category for three reasons. 
First, the proposed rule is structured to set standards only for those 
facilities that discharge dental amalgam. Second, the requirements do 
not include a size threshold because the technology is readily scaled 
to the size of the dental office. Finally, those states and localities 
that already have regulatory programs for controlling discharges of 
dental amalgam have been largely successful without subcategorization.

XIV. Proposed Regulation

A. PSES Options Selection

    Section XI discussed the technologies identified to control amalgam 
discharges from dental offices. EPA identified two basic technologies, 
amalgam separators and polishing. EPA determined separators plus 
polishing is not ``available'' as that term is used in the CCWA.
    EPA identified one technology that is available and demonstrated--
amalgam separators. EPA further identified BMPs that would ensure the 
effectiveness of the amalgam separator technology and would reduce 
discharges of dental amalgam not captured by an amalgam separator. 
Therefore, EPA developed a regulatory option based on proper operation 
and maintenance of amalgam separators that achieve a 99.0% reduction of 
total mercury from amalgam process wastewater with BMPs. Compliance 
with the numeric pretreatment standard for new and existing sources 
could be met by installation and proper operation and maintenance of an 
amalgam separator certified to meet at least 99.0% reduction of total 
mercury according to the 2008 ISO 11143 standard. Compliance with two 
additional BMPs--not flushing scrap amalgam down the drain and cleaning 
of chair side traps with non-bleach, non-chlorine cleaners--are 
necessary to prevent mercury discharges that would bypass the 
separator. EPA finds that the proposed technology basis is 
``available'' as that term is used in the CWA because it is readily 
available and feasible for all dental offices. ADA recommends its 
dentists use the technology on which this rule is based (i.e., amalgam 
separators and BMPs). Further, EPA estimates that 40% of dental offices 
currently use amalgam separators on a voluntary basis or are in states 
with state or local laws requiring the use of amalgam separators. For 
those dental offices that have not yet installed an amalgam separator, 
EPA estimates this is a low cost technology with an approximate average 
annual cost of $700 \10\ per office. EPA's economic analysis analyzes 
these costs in relation to the overall income of the regulated entities 
and shows that this proposed rule is economically achievable (see 
Section XVI). Finally, EPA also examined the non-water quality 
environmental impacts of the proposed rule and found them to be 
acceptable. See Section XX, ``Non Water Quality Environmental 
Impacts.''
---------------------------------------------------------------------------

    \10\ This estimate is based on the average annualized cost for 
dentists that do not currently have an amalgam separator. See DCN 
DA00145.
---------------------------------------------------------------------------

    EPA is not proposing to establish pretreatment standards based on 
technologies that remove dissolved mercury, or polishing. None of the 
states with mandated requirements to reduce dental mercury discharges 
requires polishing. EPA also lacks adequate performance data to truly 
assess the efficacy of polishing or its availability of ion exchange 
for nationwide use. EPA's current information suggests that polishing 
only achieves incremental removals over the BAT selected technology of 
less than one half percent of total mercury. While even very small 
amounts of mercury have environmental effects, EPA lacks sufficient 
data to conclude that there is a significant difference in the 
performance between the two technologies. EPA estimates that the 
capital costs of amalgam separators and polishing are at least four 
times that of amalgam separators alone (see DCN DA00122). Finally, EPA 
is uncertain whether existing dental offices have adequate space to 
install polishing controls. These factors led EPA to find that 
polishing is not ``available'' as that term is used in the CWA. As a 
result, EPA did not select amalgam separators followed by polishing as 
the technology basis for this proposed rule. EPA solicits data on the 
costs, performance, affordability, and availability of polishing in 
combination with amalgam separators.

B. Pollutants of Concern and Pass Through

    Of the dental amalgam constituents, mercury is of greatest concern 
to human health because it is a persistent, bioaccumulative, toxic 
chemical and can bioaccumulate three to ten times across each trophic 
level of the food chain. Mercury from dental amalgam makes its way into 
the environment when it is discharged from the dental facility to a 
POTW, where it settles into sewage sludge, or is discharged to surface 
waters. Once discharged, certain microorganisms change mercury into 
methylmercury, a form of mercury that can be absorbed by fish, 
shellfish and animals that eat fish.
    EPA finds that the technologies considered for control of amalgam 
solids will be similarly effective on other metals contained in dental 
amalgam because these metals are in a solids form, and the separation 
technology is designed to remove solids. Therefore any controls 
established for the reduction of mercury discharges will similarly 
reduce the discharge of other metals contained in amalgam. As such, EPA 
focused its consideration of regulated pollutants on mercury.

C. POTW Pass Through Analysis

    To establish pretreatment standards, EPA examines whether the 
pollutants discharged by the industry ``pass through'' a POTW to waters 
of the U.S. or interfere with the POTW operation or sludge disposal 
practices. EPA's consideration of pass through for national technology 
based categorical pretreatment standards differs from that described in 
Section VIII for general pretreatment standards. For categorical 
pretreatment standards, EPA's approach for pass through satisfies two 
competing objectives set by Congress: (1) That standards for indirect 
dischargers be

[[Page 63268]]

equivalent to standards for direct dischargers; and (2) that the 
treatment capability and performance of the POTWs be recognized and 
taken into account in regulating the discharge of pollutants from 
indirect dischargers.
    Generally, in determining whether pollutants pass through a POTW 
when considering the establishment of categorical pretreatment 
standards, EPA compares the percentage of the pollutant removed by 
typical POTWs achieving secondary treatment with the percentage of the 
pollutant removed by facilities meeting BAT effluent limitations. A 
pollutant is deemed to pass through a POTW when the average percentage 
removed by a typical POTW is less than the percentage removed by direct 
dischargers complying with BPT \11\/BAT effluent limitations. In this 
manner, EPA can ensure that the combined treatment at indirect 
discharging facilities and POTWs is at least equivalent to that 
obtained through treatment by a direct discharger, while also 
considering the treatment capability of the POTW.
---------------------------------------------------------------------------

    \11\ Best Practicable Control Technology Currently Available.
---------------------------------------------------------------------------

    In the case of this proposed rulemaking, where only pretreatment 
standards are being developed, EPA compared the POTW removals with 
removals achieved by indirect dischargers using the candidate 
technology that otherwise satisfies the BAT factors. Historically, 
EPA's primary source of POTW removal data is its 1982 ``Fate of 
Priority Pollutants in Publicly Owned Treatment Works'' (also known as 
the 50 POTW Study). The 50 POTW study presents data on the performance 
of 50 POTWs achieving secondary treatment in removing toxic pollutants. 
Results of this study demonstrate POTWs remove 90% of total mercury 
found in wastewater. EPA has data from targeted studies performed by 
NACWA and ADA that indicate a POTW can remove 95% of total mercury. 
However, these studies reflect the performance of best performing 
POTWs, as opposed to the 50 POTW Study which reflects nationwide POTWs. 
Consequently, for this proposal, EPA maintains a POTW percent removal 
rate of 90% for its nationwide pass-through analysis. In comparison, 
indirect dischargers using this proposed technology will remove 99.0% 
or more total mercury prior to discharge. Therefore, EPA concludes 
mercury passes through \12\ and is today proposing requirements to 
control its discharge.
---------------------------------------------------------------------------

    \12\ For all the metals contained in dental amalgam, EPA's 
record demonstrates that these pollutants would similarly pass 
through as defined above. See the Pollutant Reduction Estimates 
section of the TEDD for POTW removal estimates for the other metals.
---------------------------------------------------------------------------

D. Requirements

    This proposed rule would establish a pretreatment standard that 
would require removal of at least 99.0% of total mercury from amalgam 
discharges and BMPs. One way affected dental offices would be able to 
meet the standard would be to use, and properly operate and maintain, a 
dental amalgam separator certified to achieve at least 99.0% reduction 
of total mercury according to the 2008 ISO 11143 standard, to perform 
certain BMPs, and to certify to this effect. Another way affected 
dental offices would be able to meet the standard would be to certify 
that they do not install or remove amalgam except in limited emergency 
circumstances. Dentists that certify that they do not install or remove 
amalgam will be exempt from any further requirements of the proposed 
rule.
    While the proposed rule does not require the use of an amalgam 
separator to meet the numeric standard, EPA expects that most, if not 
all dentists that place or remove amalgam would use this widely 
available technology to comply with the proposed numeric standard. EPA 
expects dentists will choose to install and operate an amalgam 
separator because of the nature of dental offices, the variability of 
the flows and resulting waste streams, and the difficulty in obtaining 
a sample that represents only dental amalgam discharges. Moreover, 
amalgam separators are an easy to use, low cost technology. Dental 
offices that elect to not use an amalgam separator must meet the 
proposed numeric limit and would be subject to the oversight and 
compliance requirements for indirect discharges subject to national 
pretreatment requirements.
    In selecting an amalgam separator that meets the requirements of 
today's proposed pretreatment standards, dentists would verify that the 
amalgam separator is compliant with the 2008 ISO 11143 standard and 
meets the design specifications of the proposed regulation for their 
configuration. Once selected and installed, EPA expects dentists will 
operate and maintain the separator following all manufacturer's 
instructions and conduct inspections at least monthly to ensure all 
features are functional.
    This proposal would subject all dentists (except those specialists 
as described in Section XII) to categorical pretreatment requirements. 
EPA recognizes that some dentists covered by this proposal do not apply 
or remove dental amalgam except possibly in limited emergency 
circumstances. However, EPA, in consultation with pretreatment 
authorities, has been unable to identify a publically available source 
of information that differentiates dental offices on the basis of 
whether or not dental amalgam may reasonably be expected to be present. 
As such, this proposed rule would apply to such dischargers and require 
them to report baseline information, but it would also allow them to 
certify (at any time) that they do not and will not install or remove 
amalgam (not including infrequent emergency treatment as discussed 
below). This would fulfill their obligations under this proposed rule. 
If they subsequently elect to install or remove amalgam, they would 
then need to comply with the proposed numeric standard (e.g., proper 
operation and maintenance of an amalgam separator) and with the BMPs in 
this proposed rule.\13\
---------------------------------------------------------------------------

    \13\ EPA recognizes that dentists, infrequently, may remove 
amalgam in the course of emergency treatment. EPA does not intend 
for discharges of dental amalgam, related to only these infrequent 
emergency treatments, to preclude such dentists from certifying.
---------------------------------------------------------------------------

    EPA does not want to penalize existing dental offices or 
institutional dental facilities that have already installed amalgam 
separators either voluntarily or to comply with state or local 
requirements. EPA recognizes that these offices may currently have 
amalgam separators in place that are certified to a removal rate 
slightly less than this proposed standard. For example, some states 
require dental offices to employ amalgam separators that are certified 
to remove 95% total mercury. EPA does not propose a rule that would 
require existing separators that still have a remaining useful life to 
be retrofitted with new separators, both because of the additional 
costs incurred by dental facilities that moved ahead of EPA's proposed 
requirements to install a treatment technology and because of the 
additional solid waste that would be generated by disposal of the 
existing separators. Therefore, EPA is proposing that, as long as they 
continue to properly operate and maintain existing separators, comply 
with BMPs, and comply with recordkeeping requirements, these facilities 
would be considered in compliance with the numeric standard until ten 
years from the effective date of the final rule. EPA selected ten years 
because it appears to be a conservative estimate of the useful life of 
the existing equipment. However, if prior to that time, the currently 
installed separator needs to be replaced, these facilities would need 
to install and

[[Page 63269]]

operate an amalgam separator that meets a removal efficiency of 99.0%.
    EPA requests comment on this proposed regulatory scheme. In 
particular, EPA seeks comment on its approach for addressing offices 
where no dental amalgam is placed or removed except in limited 
emergency circumstances, and its approach for offices that have already 
installed an amalgam separator.

E. PSNS Option Selection

    As previously noted, under section 307(c) of the CWA, new sources 
of pollutants into POTWs must comply with standards which reflect the 
greatest degree of effluent reduction achievable through application of 
the best available demonstrated control technologies. Congress 
envisioned that new treatment systems could meet tighter controls than 
existing sources because of the opportunity to incorporate the most 
efficient processes and treatment systems into the facility design. EPA 
proposes PSNS that would control the same pollutants using the same 
technologies proposed for control by PSES. The technologies used to 
control pollutants at existing offices, amalgam separators and BMPs, 
are fully applicable to new offices. New dental offices can incorporate 
amalgam separators into the design and installation of their vacuum 
system. Furthermore, EPA has not identified any technologies that are 
demonstrated for new sources that are more effective than those 
identified for existing sources. Finally, EPA determined that the 
proposed PSNS present no barrier to entry. EPA has found that overall 
impacts from the proposed standards on new sources would not be any 
more severe than those on existing sources, since the costs faced by 
new sources generally will be the same as or less than those faced by 
existing sources. Therefore, EPA proposes to establish NSPS that are 
the same as those proposed for PSES.
    EPA does not propose to establish more stringent requirements for 
new sources based on technologies that remove dissolved mercury (i.e., 
polishing) for the same reasons stated above for existing standards.

XV. Technology Costs

    This section summarizes EPA's approach for estimating compliance 
costs, while the TEDD provides detailed information on the methodology. 
EPA's cost methodology assumes dental offices would use the required 
BMPs in combination with 2008 ISO 11143 amalgam separators on the 
market today to comply. See DCN DA00138. EPA categorized all of the 
costs as either capital costs \14\ (one-time costs associated with 
planning or installation of technologies), as operation and maintenance 
(O&M) costs (costs that occur on a regular ongoing basis such as 
inspection or cleaning of the unit or annual purchases of amalgam 
cartridges), or as reporting costs. All final cost estimates are 
expressed in terms of 2010 dollars.
---------------------------------------------------------------------------

    \14\ See Section XVI and the Economic Section of the Technical 
Development Document for information on how EPA annualized costs.
---------------------------------------------------------------------------

    EPA estimated compliance costs associated with this proposal using 
data collected through EPA's Health Services Industry Detailed Study 
(August 2008) [EPA-821-R-08-014], a review of the literature, and 
information supplied by vendors. EPA's cost estimates represent the 
incremental costs for a dental office to comply with this proposed 
rule. For costing purposes, EPA differentiated dental offices by those 
that already use amalgam separators and those that do not.
    EPA recognizes that some fraction of dental offices subject to this 
proposed rule may not place or remove amalgam and proposes to allow 
them to submit a one-time baseline monitoring report. Such dental 
offices would be exempt from this rule so long as they do not place or 
remove amalgam. Should the status of the dental office change, the 
certification would no longer be valid. For example, if a dental office 
so certifies and is sold, the new owner must similarly so certify or 
would need to comply with the rule. See Sec.  441.10. EPA estimates the 
costs associated with this one-time only certification to be $22.
    In general, one approach that EPA takes to estimate compliance 
costs is to use facility-specific data to determine what requirements 
apply to a given facility and whether that facility would already meet 
the proposed requirements. This approach requires facility specific 
technical and financial data. In this case, EPA would need such data 
for approximately 110,000 dental offices estimated to be subject to 
this rule. Such data are not available. An alternative approach often 
used by EPA is to develop a series of model facilities that exhibit the 
typical characteristics of the affected facilities and calculate costs 
for each model facility. EPA can then determine how many of the 
affected facilities are represented nationally by each model facility 
to represent the full universe of affected facilities.

A. Methodology for Developing Model Dental Office Costs

    EPA used the model approach to estimate costs for facilities that 
place or remove amalgam for this proposal. The model facility approach 
used in this effort involved calculating compliance costs for each of 
the size classes of dental offices described in Section IX of this 
preamble. In other words, EPA developed compliance costs for six models 
based on the number of chairs in an office. The ranges for each model 
are as follows: 1 to 2 chairs, 3 chairs, 4 chairs, 5 chairs, 6 chairs, 
and 7+ chairs (average of 10 chairs). In addition to each of the size 
class models, EPA developed a model facility to represent very large 
offices such as clinics and universities. This is discussed separately 
in Section XV. B., below.
    EPA developed two sets of costs for each model: one for facilities 
that do not use an amalgam separator and one for facilities that do. 
For those that do not use an amalgam separator, EPA estimated capital 
costs and operation and maintenance costs. Capital costs include 
purchase of the separator and installation. Recurring costs include 
replacement of the cartridge, and operation and maintenance costs. A 
summary of costs for dental offices that do not currently use amalgam 
separators may be found in Tables XV-1 and XV-2.

    Table XV-1--Summary of One Time Model Facility Costs ($2010) for Dental Offices That Do Not Currently Use
                                               Amalgam Separators
----------------------------------------------------------------------------------------------------------------
                                                          Number of chairs in the model dental office
                Cost element                 -------------------------------------------------------------------
                                                   1 or 2      3, 4, or 5 \15\         6                7+
----------------------------------------------------------------------------------------------------------------
Separator Purchase..........................             $502             $599           $1,058           $1,531

[[Page 63270]]

 
Installation................................              250              250              250              250
----------------------------------------------------------------------------------------------------------------


    Table XV-2--Summary of One Time Model Facility Costs ($2010) for Dental Offices That Do Not Currently Use
                                               Amalgam Separators
----------------------------------------------------------------------------------------------------------------
                                                          Number of chairs in the model dental office
                Cost element                 -------------------------------------------------------------------
                                                   1 or 2      3, 4, or 5 \16\         6                7+
----------------------------------------------------------------------------------------------------------------
Replacement Parts...........................             $195             $219             $430             $647
O&M Including Recycling.....................              216              216              216              216
----------------------------------------------------------------------------------------------------------------

    For those  facilities that already have an amalgam separator, EPA 
calculated costs for certain additional recurring operation and 
maintenance associated with the amalgam separator compliance  option in 
this proposal. Recurring costs include replacement of the cartridge and 
operation and maintenance costs. A summary of these costs may be found 
in Table XV-3. This is a conservative approach to costing, however, 
because some of these facilities would presumably continue to operate 
and maintain the separators that they have already chosen or been 
required to install.
---------------------------------------------------------------------------

    \15\ EPA assumed the separator can be sized for 3, 4, or 5 
chairs, but has kept these three model office sizes distinct because 
the economic analysis evaluates different revenues for each of these 
sized offices.
    \16\ EPA assumed the separator can be sized for 3, 4, or 5 
chairs, but has kept these three model office sizes distinct because 
the economic analysis evaluates different revenues for each of these 
sized offices.

    Table XV-3--Summary of Annual Model Facility Costs ($2010) for Dental Offices That Currently Use Amalgam
                                                   Separators
----------------------------------------------------------------------------------------------------------------
                                                          Number of chairs in the model dental office
                Cost element                 -------------------------------------------------------------------
                                                   1 or 2      3, 4, or 5 \17\         6                7+
----------------------------------------------------------------------------------------------------------------
Replacement Parts...........................              $98             $110             $215             $324
O&M including recycling.....................              116              116              116              116
----------------------------------------------------------------------------------------------------------------

    In assessing  the long term costs of rule compliance for these 
model facilities (those with and without existing separators), EPA 
estimated that amalgam separators would have a service life of 10 
years, at which time the amalgam separators would need to be replaced. 
For the purposes of cost estimates for this proposal, EPA assumed that 
all offices regardless of the original technology in-place would incur 
the full cost of purchasing amalgam separators at the time of 
reinstallation. However, because various modifications needed by the 
office for initial amalgam separator installation would have already 
been completed, EPA has projected that amalgam separators replaced 
beyond year 10 would be installed at one-half of the cost of the 
original installation. For example, EPA assumed plumbing modifications 
for initial installation would cost $250 per office, but that replaced 
equipment would cost $125 to install. EPA assumed that dental offices 
would continue to incur recurring expenses such as O&M in the same way 
as described for the initial installation.
---------------------------------------------------------------------------

    \17\ EPA assumed the separator can be sized for 3, 4, or 5 
chairs, but has kept these three model office sizes distinct because 
the economic analysis evaluates different revenues for each of these 
sized offices.
---------------------------------------------------------------------------

    Finally, all dental offices subject to this proposed rule will also 
have reporting requirements and BMP requirements. EPA also included 
reporting costs for one-time preparation of a baseline report and 
initial compliance report and recurring costs associated with 
preparation of an annual certification statement. Section XI describes 
the BMPs in this proposal. EPA projects that there will be no 
incremental costs associated with these BMPs, because 1) costs for non-
oxidizing, pH neutral line cleaners are roughly equivalent to other 
line cleaners; and 2) dentists will not incur additional costs by 
changing the location for flushing scrap amalgam.

[[Page 63271]]

B. Methodology for Developing Costs for Institutional Facilities

    Institutional dental service facilities (e.g., clinics or dental 
schools), have a larger number of chairs than the typical dental 
office. For these institutional dental facilities, EPA developed a 
costing methodology based on the methodology for offices described 
above. For purposes of costs, EPA assumed the average institutional 
facility has 15 chairs. In the methodology described previously, the 
model practice with the largest number of chairs for which EPA 
developed cost information is the 7+ chair model with an average of 10 
chairs. Scaling the information on costs for the 10 chair model 
facility to a 15 chair operation using a straight ratio yields costs at 
these institutional facilities at 1.5 times the costs estimated for the 
largest chair range shown in Table XV-1 and Table XV-2. These costs are 
likely overstated as they do not reflect opportunities the largest 
offices may have to share costs,\18\ and they do not assume any 
economies of scale. EPA solicits comment and data regarding EPA's 
analysis of clinics and institutional facilities.
---------------------------------------------------------------------------

    \18\ For example, multiple offices located in a single building 
or complex may be able to share plumbing, vacuum systems, and may be 
able to install a larger separator rather than each office having 
its own separator.
---------------------------------------------------------------------------

XVI. Economic Impact Analysis

    This section summarizes EPA's assessment of the costs and impacts 
of the proposed pretreatment standards on the regulated industry.

A. Social Cost Estimates

    As described earlier in Section XIV of this preamble, EPA proposes 
PSES and PSNS based on a widely available technology, amalgam 
separator, and employment of BMPs. Section XV provides a detailed 
explanation of how EPA estimated compliance costs for model dental 
offices. As described there, EPA developed compliance costs for six 
models based on the number of chairs in an office. The ranges for each 
model are as follows: 1 to 2 chairs, 3 chairs, 4 chairs, 5 chairs, 6 
chairs, and 7+ chairs (average of 10 chairs). In addition to each of 
the size class models, EPA developed a model facility to represent 
institutional facilities such as clinics and universities.
    For each model facility, EPA estimated compliance costs for dental 
offices that currently use a separator, those that do not have a 
separator in place, and those that certify that they do not place or 
remove amalgam. For those that do not currently use a separator, EPA 
estimated costs as either capital costs (one-time costs associated with 
planning or installation of technologies), as O&M costs (costs that 
occur on a regular ongoing basis such as inspection or cleaning of the 
unit, annual purchases of amalgam cartridges, and recycling), and as 
reporting costs. For those that use a separator (approximately 40% of 
dental offices as reported in Section VIII), EPA estimated O&M costs 
and reporting costs only. As applicable, EPA annualized the capital 
costs over a 20-year period at a discount rate of 3%\19\  and summed 
these costs with the O&M and reporting costs to determine an annual 
compliance cost estimate for each model facility. In order to develop a 
national estimate of social costs \20\ based on these model facilities, 
EPA estimated the number of dental offices represented by each model 
facility. As explained in Section IX, EPA estimated the number of 
dental offices based on data from the 2007 Economic Census \21\ 
describing the number of establishments in the Offices of Dentists 
NAICS (621210), and their annual revenue. Because reported 
establishments were described by their annual revenue and not number of 
chairs (the basis of model compliance costs), EPA used data from two 
surveys, a Colorado survey and an ADA survey, to correlate the 
estimated number of chairs per office to the revenue range of dental 
offices. Because EPA used two different data sources, results are 
presented as a range. Details of the relationship between chairs and 
revenue can be found in the TEDD.
---------------------------------------------------------------------------

    \19\ See the TEDD for the reported analyses using a 7% discount 
rate.
    \20\ Costs of the rule, from the standpoint of cost to society, 
include compliance costs and administrative costs to control 
authorities. Social costs would also incorporate any adjustment 
based on a quantity demand response to a change in price driven by a 
price change due to cost pass-through to consumers. For this 
analysis, EPA is not able to demonstrate an observable change in 
price for dental services, therefore no observable change in amount 
of visits (quantity demanded). Therefore EPA makes no adjustment to 
social costs based on a change in quantity.
    \21\ EPA adjusted the 2007 Economic Census revenue values to 
reflect 2010 dollars.
---------------------------------------------------------------------------

    To estimate nationwide social costs, EPA multiplied the estimated 
total annualized costs of rule compliance for each model facility by 
the estimated number of dental offices represented by that model (i.e. 
with the indicated number of chairs and with/without existing amalgam 
separators). EPA also accounted for some dental offices that may not 
place or remove amalgam and assigned them costs only for a one-time 
baseline monitoring report. EPA then summed the values for each chair 
range over the number of chair ranges to yield the total estimated 
compliance cost.
    Similarly, EPA calculated costs for institutional facilities by 
multiplying the compliance cost for its model institutional facility by 
the number of estimated institutional facilities indicated in Section 
IX. Lastly, EPA estimated costs for control authorities for 
administering the Dental Amalgam Rule.\22\ Details of this cost 
analysis can be found in the TEDD. See Table XVI-1 for EPA's estimate 
of nationwide annualized costs for each chair range represented by 
EPA's model facilities as well as EPA's estimate of total nationwide 
annualized costs for this proposed rule.
---------------------------------------------------------------------------

    \22\ As a point of clarification, for this proposal, social 
costs equal the sum of compliance costs and administrative costs.

     Table XVI-1--Total Annualized Social Costs by Number of Chairs
                       [Millions of 2010 dollars]
------------------------------------------------------------------------
                                    Total annualized costs by chair size
                                                     \1\
         Number of chairs          -------------------------------------
                                     Colorado survey       ADA Survey
------------------------------------------------------------------------
1-2 chairs........................               $3.4               $4.4
3 chairs..........................                9.5               16.3
4 chairs..........................               11.0
5 chairs..........................                5.4               14.8
6 chairs..........................                4.7
7+ chairs.........................                9.5               12.8
Large Dental Facilities...........                0.1                0.1

[[Page 63272]]

 
Cost to Control Authorities.......                0.9                0.9
                                   -------------------------------------
    Total Annualized Social Costs.               44.5               49.4
------------------------------------------------------------------------
\1\ EPA assumed that initial capital outlays and initial incurrence of
  ongoing compliance expenses would occur in the third year following
  rule promulgation. EPA assumed that the amalgam separator technology
  would have a service life of 10 years, and used a 20-year analysis
  period to allow for one-time replacement of capital equipment 10 years
  following the initial installation. A 3% discount rate was used for
  the analysis reported in this table, see the TEDD for the analysis
  with a 7% discount rate.

B. Economic Impact Methodologies

    EPA devised a set of tests for analyzing economic achievability. As 
is often the practice, EPA conducted a cost-to-revenue analysis to 
examine the relationship between the costs of the proposed rule to 
current (or pre-rule) dental office revenues. In addition, EPA chose to 
examine the financial impacts of the proposed rule using two measures 
that utilize the data EPA has on dental office baseline assets and 
estimated replacement capital costs: (1) Ratio of the Proposed Rule's 
Capital Costs to Total Dental Office Capital Assets and (2) Ratio of 
the Proposed Rule's Capital Costs to Annual Dental Office Capital 
Replacement Costs.
    EPA did not conduct a traditional closure analysis for this 
proposed rule because EPA does not have detailed data on baseline 
financial conditions of dental offices. Also, closure analyses 
typically rely on accounting measures such as present value of after-
tax cash flow. However, such accounting measures are difficult to 
implement for businesses that are organized as sole proprietorships or 
partnerships, as is the case in the dental industry. Still, the 2007 
Economic Census reports that approximately 700 offices of the 
approximately 110,000 total offices had revenue of less than $25,000 
(2007 dollar basis). In reviewing the implied operating characteristics 
of these low revenue offices, EPA considered whether these offices 
should be excluded from the analyses on any of the following bases:
    <bullet> These low revenue offices could be single-dentist and/or 
part-time businesses that provide services as a subcontractor on an 
independent fee-for-service basis, such as dental hygiene, in general 
service dental offices that are owned and operated by a larger dental 
practice. Because these establishments would not be the primary owner/
operator of the dental offices in which they provide services, they 
would not directly incur the compliance costs of a Dental Amalgam Rule. 
If they incurred any of these costs, it would be on a limited 
fractional share basis, most likely in proportion to the total value of 
their services as a fraction of the total revenue in the office. On the 
other hand, if these operators offer their services in a competitive 
market, it may be that none of the compliance costs are shared by these 
subcontractors.
    <bullet> Another possibility is these very low revenue offices 
could be non-profit groups which provide pay-as-you-can or free 
services to a low-income populations. In this case, these small 
businesses may be viable enterprises because they receive in-kind 
donations not counted as revenue, e.g., services of a practicing 
dentist.
    <bullet> Alternatively, these low revenue offices may be non-viable 
as for-profit businesses, if they are attempting to operate as general 
service dental practices. This is based on EPA's assessment (see Ratio 
of Proposed Rule Capital Costs to Total Dental Office Capital 
Replacement Costs, below) that 1-2 chair offices would incur pre-rule 
capital replacement costs of approximately $23,500 per year. This cost 
represents all or a substantial fraction of annual revenue of the 
business in the below-$25,000 revenue range. Accordingly, these 
businesses may not be operating viably as for-profit general service 
dental offices.
    As such, EPA could consider these offices to be the equivalent of 
baseline closures as traditionally accounted for in cost and economic 
impact analysis for effluent guidelines rulemakings. As a result of the 
uncertainty here, EPA analyzed the impacts twice: (1) Excluding dental 
offices that could represent baseline closures and (2) including all 
offices in the analysis. EPA solicits comment for additional 
information on these low revenue dental offices.
1. Cost-to-Revenue Analysis
    To provide an assessment of the impact of the rule on dental 
offices, EPA used a cost-to-revenue analysis as is standard practice 
for ELGs when looking at impacts to small businesses. The cost-to-
revenue analysis compares the total annualized compliance cost of each 
regulatory option with the revenue of the entities. It is also used 
under the Regulatory Flexibility Act (RFA) to determine if a rule has 
the potential to have a significant impact on a substantial number of 
small entities. EPA apportioned all dental offices into Economic Census 
revenue ranges. Using the relationship between revenue and number-of-
chairs previously developed, each revenue range was assigned to a 
number-of-chairs category which determined its annual costs. EPA looked 
at whether all, some, or none of the offices in each revenue range 
would exceed the 1% or 3% threshold (to signal the potential for 
significant impact), and summed across chair-size categories to assess 
impact to the industry. To incorporate the discussion of low revenue 
dental offices described in Section XVI.B above, this analysis is 
conducted twice: (1) Excluding dental offices that could represent 
baseline closures and (2) including all offices in the analysis.
2. Ratio of the Proposed Rule's Capital Costs to Total Dental Office 
Capital Assets
    This ratio examines the initial spending on capital costs of 
compliance in relation to the baseline value of assets on the balance 
sheet of dental office businesses. EPA assumes a low ratio implies 
limited impact on dental offices' ability to finance the initial 
spending on capital costs of the proposed rule. A high ratio may still 
allow costs to be financed but could imply a need to change capital 
planning and budgeting. EPA relied on data from Risk Management 
Association (RMA) \23\ to estimate the average asset-to-sales ratio

[[Page 63273]]

in each number-of-chairs category for the dental office sector. This 
ratio was then applied to the revenue range/number-of-chairs categories 
to find an asset value for the minimum (reported as low in Table XVI-3) 
and maximum (reported as high in Table XVI-3) revenue values for that 
number-of-chairs category. EPA used these baseline assets by number-of-
chairs category as the denominator for the ratio. Total proposed rule 
compliance costs, as described in Section XVI.B above, were assigned to 
each number-of-chairs category as the numerator for the ratio. To 
incorporate the discussion of low revenue dental offices described in 
Section XVI.B above, this analysis is conducted twice: (1) Excluding 
dental offices that could represent baseline closures, and (2) 
including all offices in the analysis. This analysis assumes a minimum 
revenue value of $5,000 for the lowest revenue range to prevent 
division by zero.
---------------------------------------------------------------------------

    \23\ Risk Management Association reports financial statement 
information received from lending institutions, for businesses in a 
wide range of economic sectors, including Dental Offices. These data 
include a wide range of income statement and balance sheet 
information as well as financial and operating ratios.
---------------------------------------------------------------------------

    The RMA data contains the limitation that it may not be fully 
representative of all dental offices, because it only represents dental 
offices that are successful borrowers. It is possible that offices that 
are not financially healthy may be underrepresented in the RMA data. 
This would tend to understate EPA's finding of impacts.
3. Comparison of the Proposed Rule's Capital Costs to Annual Dental 
Office Capital Replacement Costs
    EPA also compared the initial spending on capital costs of 
compliance associated with this proposed rule to the estimated capital 
replacement costs for a dental office business (e.g., computer systems, 
chairs, x-ray machines, etc.). The capital replacement costs represent 
a value that dental offices may reasonably expect to spend in any year 
to replace and/or upgrade dental office capital equipment. EPA assumes 
a low ratio implies limited impact on dental offices' ability to 
finance the initial spending on capital costs of the proposed rule. A 
high ratio may still allow costs to be financed but could imply a need 
to change capital planning and budgeting. However, because EPA expects 
that annual dental office capital replacement would be smaller than 
total dental office capital assets, this ratio is likely to result in a 
higher value than the previous ratio. Because this ratio is based on a 
different data source, it provides an independent check that abstracts 
from the limitations of the RMA data.
    EPA used data from Safety Net Dental Clinic Manual, prepared by the 
National Maternal & Child Oral Health Resource Center at Georgetown 
University (see DCN DA00143). This study examines data describing the 
equipment needs and costs for starting a dental practice for a range of 
different number-of-chairs including information on the life of the 
dental equipment. EPA then used these data to estimate capital 
replacement costs, accounting for the total value of equipment 
purchases for different numbers of chairs, and the composition of 
purchases by equipment life category. EPA used these replacement 
capital costs by number-of-chairs as the denominator for the ratio. 
Total proposed rule compliance costs, as described in Section XVI.B 
above, were assigned to each number-of-chairs as the numerator for the 
ratio.
    Because the data are for starting a dental clinic instead of a 
dental practice, EPA is taking comment to solicit additional 
information on equipment needs and costs for starting a dental 
practice, including information on the life of the dental equipment. 
See the TEDD for details on this analysis.

C. Results of Impact Analysis

1. Cost-to-Revenue Analysis Results
    Following the methodology outlined in XVI.B, EPA estimated the 
occurrence of annualized compliance costs exceeding the 1% and 3% of 
revenue thresholds for the proposed option twice: (1) Excluding dental 
offices that could represent baseline closures, and (2) including all 
offices in the analysis.
    Table XVI-2 summarizes the results from this analysis. As shown 
there, under either scenario, over 99% of dentists would incur 
annualized compliance costs of less than 1% of revenue. With baseline 
set-asides excluded from the analysis, 507 offices (0.5% of offices 
using dental amalgam and exceeding the set-aside revenue threshold) are 
estimated to incur costs exceeding 1% of revenue; no offices are 
estimated to incur costs exceeding 3% of revenue. With baseline set-
asides included in the analysis, 965 offices (0.9% of offices using 
dental amalgam) are estimated to incur costs exceeding 1% of revenue; 
221 offices (0.2% of offices using dental amalgam) are estimated to 
incur costs exceeding 3% of revenue.

                              Table XVI-2--Cost-to-Revenue Analysis Impact Summary
----------------------------------------------------------------------------------------------------------------
                                                         Costs >1% Revenue               Costs >3% Revenue
        Number of chairs           Total offices ---------------------------------------------------------------
                                   by chair size      Number          Percent         Number          Percent
----------------------------------------------------------------------------------------------------------------
                               Excluding Baseline Set-Aside Offices from Analysis
----------------------------------------------------------------------------------------------------------------
1-2 chairs......................          12,197             507             4.2               0             0.0
3 chairs........................          25,835               0             0.0               0             0.0
4 chairs........................          27,976               0             0.0               0             0.0
5 chairs........................          15,194               0             0.0               0             0.0
6 chairs........................          12,047               0             0.0               0             0.0
7+ chairs.......................          16,611               0             0.0               0             0.0
                                 -------------------------------------------------------------------------------
    Total.......................         109,859             507             0.5               0             0.0
----------------------------------------------------------------------------------------------------------------
                                Including Baseline Set-Aside Offices in Analysis
----------------------------------------------------------------------------------------------------------------
1-2 chairs......................          12,197             965             7.9             221             1.8
3 chairs........................          25,835               0             0.0               0             0.0
4 chairs........................          27,976               0             0.0               0             0.0
5 chairs........................          15,194               0             0.0               0             0.0
6 chairs........................          12,047               0             0.0               0             0.0
7+ chairs.......................          16,611               0             0.0               0             0.0
                                 -------------------------------------------------------------------------------

[[Page 63274]]

 
    Total.......................         109,859             965             0.9             221             0.2
----------------------------------------------------------------------------------------------------------------
Source: EPA analysis.

2. Ratio of the Proposed Rule's Capital Costs to Total Dental Office 
Capital Assets
    Table XVI-3 reports the findings from this analysis, specifically 
the weighted average of the initial spending on the proposed rule's 
capital costs divided by total assets of dental office across the 
revenue range/number-of-chairs analysis combinations. With baseline 
set-asides excluded from the analysis, the resulting initial capital 
costs to total capital assets values are low, with an average value 
0.5% to 1.0% for the no technology in-place case and 0% for the 
technology in-place case. With baseline closures included in the 
analysis, the resulting initial capital costs to total capital assets 
values are low, with an average value 0.6% to 1.2% for the no 
technology in-place case and 0% for the technology in-place case.

         Table XVI-3--Initial Spending as Percentage of Pre-Rule Total Dental Office Capital Assets \1\
----------------------------------------------------------------------------------------------------------------
                                                                 Technology in place     No technology in place
                      Number of chairs                       ---------------------------------------------------
                                                                  Low          High         Low          High
----------------------------------------------------------------------------------------------------------------
                            Excluding Baseline Set-Aside Establishments from Analysis
----------------------------------------------------------------------------------------------------------------
1-2 chairs..................................................          0.1          0.1          2.7          1.3
3 chairs....................................................          0.0          0.0          0.8          0.5
4 chairs....................................................          0.0          0.0          0.5          0.3
5 chairs....................................................          0.0          0.0          0.3          0.2
6 chairs....................................................          0.0          0.0          0.3          0.2
7+ chairs...................................................          0.0          0.0          0.2          0.2
Weighted Average............................................          0.0          0.0          0.7          0.4
----------------------------------------------------------------------------------------------------------------
                             Including Baseline Set-Aside Establishments in Analysis
----------------------------------------------------------------------------------------------------------------
1-2 chairs..................................................          0.2          0.1          3.7          1.7
3 chairs....................................................          0.0          0.0          0.8          0.5
4 chairs....................................................          0.0          0.0          0.5          0.3
5 chairs....................................................          0.0          0.0          0.3          0.2
6 chairs....................................................          0.0          0.0          0.3          0.2
7+ chairs...................................................          0.0          0.0          0.2          0.2
Weighted Average............................................          0.0          0.0          0.8          0.5
----------------------------------------------------------------------------------------------------------------
\1\ EPA used the baseline asset value for the minimum (reported as low) and maximum (reported as high) revenue
  values by number-of-chairs category as the denominator for the ratio. Total proposed rule compliance costs, as
  described in Section XVI.B above, were assigned to each number-of-chairs category as the numerator for the
  ratio.

3. Ratio of the Proposed Rule's Capital Costs to Annual Dental Office 
Capital Replacement Costs Results
    EPA compared the estimated total initial spending on the proposed 
rule's capital costs to the estimated capital replacement costs across 
all chair-sizes. The resulting values for the proposed option range 
from 2.9% to 3.5%, with a weighted average of 2.9% across all chair 
size ranges.

 Table XVI-4--Initial Spending as Percentage of Estimated Annual Dental
                  Office Capital Replacement Costs \1\
------------------------------------------------------------------------
                      Number of chairs                         Percent
------------------------------------------------------------------------
1-2 chairs.................................................          3.4
3 chairs...................................................          3.2
4 chairs...................................................          2.6
5 chairs...................................................          2.2
6 chairs...................................................          2.9
7 chairs...................................................          3.5
8 chairs...................................................          3.1
9 chairs...................................................          2.9
Weighted Average...........................................          2.9
------------------------------------------------------------------------
Source: EPA Analysis.
\1\ EPA estimated capital replacement costs, accounting for the total
  value of equipment purchases for different numbers of chairs, and the
  composition of purchases by equipment life category by number-of-
  chairs as the denominator for the ratio. Total proposed rule
  compliance costs, as described in Section XVI.B, were assigned to each
  number-of-chairs as the numerator for the ratio.

D. Economic Achievability

    The analyses performed above demonstrate the impact of this 
proposed rule on the dental office sector. In the cost-to-revenue 
analysis, EPA found that no more than 0.2% of offices, mostly in the 
lower revenue ranges, would potentially incur costs in excess of 3% of 
revenue. The two financial ratios reported in Tables XVI-3 and XVI-4 
show that the proposed option would not cause dental offices to 
encounter difficulty in financing initial spending on capital costs of 
the proposed regulatory option. Based on the results of the three 
analyses above in combination, and EPA's inability at this time to 
conduct a traditional facility closure analysis, EPA has determined 
that the proposed pretreatment standard is economically achievable. EPA 
notes that, due to a lack of data, the economic

[[Page 63275]]

impact analyses did not include large institutional facilities. 
However, the results of the economic analyses performed on a range of 
office sizes indicate that this proposal is economically achievable at 
every level. Therefore, EPA projects the rule would similarly be 
achievable for large institutional facilities. EPA requests comment on 
this projection and data to perform economic achievability analyses.

E. Economic Impact for New Sources

    EPA determined that this proposed pretreatment standard for new 
sources would not impose a barrier to entry. EPA relied on data 
describing the equipment needs and costs for starting a dental practice 
as compiled in Safety Net Dental Clinic Manual, prepared by the 
National Maternal & Child Oral Health Resource Center at Georgetown 
University (see DCN DA00143). Information from the Georgetown Manual 
demonstrates that the amalgam separator capital costs (based on costs 
for existing model facilities as described in Section XI) comprised 
0.3% to 0.4% of the cost of starting a dental practice and, therefore, 
does not pose a barrier to entry.

 Table XVI-5--Initial Spending as Percentage of Estimated Dental Office
                             Start-Up Costs
------------------------------------------------------------------------
                      Number of chairs                         Percent
------------------------------------------------------------------------
1-2 chairs.................................................          0.4
3 chairs...................................................          0.4
4 chairs...................................................          0.3
5 chairs...................................................          0.3
6 chairs...................................................          0.3
7 chairs...................................................          0.4
8 chairs...................................................          0.4
9 chairs...................................................          0.3
Weighted Average...........................................          0.3
------------------------------------------------------------------------
Source: EPA Analysis.

XVII. Pollutant Reductions to POTWs and Surface Waters

    Consistent with its costing methodology, EPA's pollutant reduction 
methodology assumes 2008 ISO 11143 amalgam separators on the market 
today with BMPs, the proposed technology basis, would be used to comply 
with this proposed rule. As was the case for costing, EPA does not have 
office specific discharge data for the approximately 110,000 dental 
offices potentially subject to this proposal. Instead, EPA has modeled 
the discharges of mercury based on nationwide estimates of amalgam 
restorations and removals, and did not calculate the pollutant 
reductions on a per office basis. Rather, EPA calculated average 
mercury loadings by dividing the total number of annual procedures by 
the total number of dentists performing the procedure.\24\ This is the 
same approach and data that EPA presented in its Health Services 
Industry Detailed Study (EPA 821-R-08-014). EPA did not receive 
comments on this part of the health study that would cause EPA to 
reconsider its approach, and, therefore, EPA did not change the overall 
methodology. The following sections describe the method in more detail.
---------------------------------------------------------------------------

    \24\ Because this approach is based on the number of dentists, 
it includes those dentists both at offices and institutional 
facilities.
---------------------------------------------------------------------------

A. Nationwide Estimate of Annual Mercury Discharges From Dental Offices

    First, EPA estimated the amount of mercury potentially discharged 
nationwide through amalgam restorations. EPA's main source of the data 
underlying all of the estimates related to restorations is Vandeven and 
McGinnis, 2005 (DCN 00163). EPA estimates 71 million restorations occur 
at dental offices annually and that these restorations are performed 
with one amalgam capsule per restoration. Each amalgam capsule contains 
450 mg of mercury and, on average, 75% of the capsule is used for the 
filling, with the remaining 25% remaining in the capsule. Therefore, 
340 mg of mercury (75% of the capsule) are used per filling. Further, 
9% of the 340 mg of mercury, or 31 mg, is discharged to the POTW as 
carvings and filings or other waste. Thus, EPA estimates a total of 2.4 
tons of mercury nationwide \25\ is discharged annually to POTWs from 
restorations.
---------------------------------------------------------------------------

    \25\ 71 million restorations times 31 mg per restoration.
---------------------------------------------------------------------------

    Second, EPA modeled mercury discharges from amalgam removals. 
Similar to restorations, EPA's main source of the data underlying all 
of the estimates related to amalgam removals is Vandeven and McGinnis, 
2005. Based on this information, EPA estimates approximately 97 million 
amalgam removals occur each year. An average of 300 mg mercury is 
removed from the filling. Ninety percent of the removed filling is 
assumed to be discharged to wastewater, and the other 10% is handled as 
dry waste and/or gray bagged. Thus, EPA estimates 29 tons of mercury 
are discharged to POTWs from removals each year.
    Summing the total mercury discharged from restorations plus that 
associated with filling removals, 31.4 tons of mercury are potentially 
discharged annually to POTWs from dental offices. However, these 
calculations do not account for the amount of mercury removed at the 
dental office and prior to POTW discharge through existing chair side 
traps, vacuum pump filters, and/or amalgam separators as described 
below.

B. National Estimate of Annual Baseline Discharges of Mercury From 
Dental Offices to POTWs

    As described in Section VIII, EPA estimates that 40% of dental 
offices currently operate dental amalgam separators. Thus, on a 
nationwide basis, approximately 65,000 dental offices currently do not 
have separators and 44,000 offices already have separators in place. Of 
the offices that do not currently have separators in place, EPA assumed 
that 20% do not install or remove amalgam, but EPA requests comment on 
this assumption. For the remainder, based on information in its record, 
EPA assumes all offices have chair side traps or a combination of chair 
side traps and vacuum filters that result in 68% and 78% collection of 
dental amalgam, respectively (Vandeven and McGinnis). After accounting 
for mercury reductions achieved through existing chair side traps, 
vacuum filters, and separators, as appropriate, EPA estimates the 
offices without separators that place or remove amalgam collectively 
discharge a total of 4.4 tons of mercury to POTWs per year. The offices 
with separators collectively discharge approximately 63 pounds of 
mercury to POTWs per year. Thus, EPA calculates the current nationwide 
annual baseline pounds of mercury discharged to POTWs from dental 
offices to be 4.4 tons mercury (out of a total of the 31.4 tons mercury 
originally generated). See Chapter 10 of the TEDD for more information.

C. National Estimate of Annual Baseline Discharges of Other Metals 
Contained in Amalgam From Dental Offices to POTWs

    Amalgam is comprised of roughly 49% mercury, 35% is silver, 9% tin, 
6% copper and 1% zinc \26\ (DCN DA00131). As explained earlier in 
Section XI, EPA concludes the technology basis for this proposal would 
be equally effective in reducing discharges of silver, tin, copper, and 
zinc as it is in reducing mercury. EPA similarly assumes chair side 
traps and the combination of chair side traps and vacuum filters will 
result in 68% and 78% collection of these metals, respectively. 
Accordingly, after accounting for existing technologies at dental 
offices, EPA estimates that in

[[Page 63276]]

addition to 4.4 tons of mercury, approximately 4.6 tons of these 
additional metals are discharged to POTWs annually for a total metal 
discharge to POTWs of 9 tons annually.
---------------------------------------------------------------------------

    \26\ It also contains small amounts of indium and palladium. EPA 
did not estimate discharges of these two pollutants.
---------------------------------------------------------------------------

D. National Estimate of Annual Pollutant Reductions to POTWs Associated 
With This Proposal

1. Mercury
    EPA estimates the 52,000 offices that install separators would 
obtain an additional 99.0% removal by amalgam separator (median removal 
efficiency of amalgam separators; see 7.1 of TEDD). This would result 
in reduction of total mercury discharges to POTWs by 4.3 tons. Because 
dissolved mercury accounts for much less than 1% of total mercury (DCN 
DA00018), and because amalgam separators are not effective in removing 
dissolved mercury, the dissolved mercury contribution and associated 
reduction in loads is assumed to be negligible. EPA solicits comment 
and data on this assumption.
2. Other Metals
    As explained earlier in Section XI, EPA concludes the technology 
basis for this proposal would be equally effective in reducing 
discharges of silver, tin, copper, and zinc as it is in reducing 
mercury. Accordingly, EPA estimates a reduction of these metal 
discharges to POTWs of approximately 4.5 tons.
3. Total Reductions
    EPA estimates this proposal would annually reduce mercury 
discharges by 4.3 tons and other metal discharges by 4.5 tons for a 
total annual reduction to POTWs of 8.8 tons.

E. National Estimate of Annual Pollutant Reductions to Surface Waters 
Associated With This Proposal

    In order to evaluate final discharges of mercury (and other metals) 
to waters of the U.S. by the POTW, EPA used its 50 POTW Study to 
calculate POTW removals of each metal. As explained above, at baseline 
and prior to implementation of this proposal, EPA estimates 4.4 tons of 
dental mercury is collectively discharged annually to POTWs. Based on 
the 50 POTW Study, EPA estimates POTWs remove 90% of the 4.4 tons 
mercury from the wastewater. Thus, POTWs collectively discharge 880 lbs 
of mercury from dental amalgam to surface waters annually. Under this 
proposed rule, 99.0% of the solid mercury currently discharged annually 
to POTWs will be removed prior to the POTW. The POTWs then further 
remove 90% of total mercury from the wastewater. This reduces the total 
amount of dental mercury discharged from POTWs nationwide to surface 
water to 14 lbs of mercury annually. In other words, discharges of 
mercury to waters of the U.S. are expected to be reduced by 860 pounds 
per year.\27\ Similarly, EPA's 50 POTW Study data shows 79% to 88% of 
other metals in the wastewater are removed by POTWs. As explained 
above, EPA estimates 4.6 tons of other metals are also collectively 
discharged annually to POTWs. Thus POTWs collectively discharge 
approximately 1,280 lbs of other metals to surface waters annually. 
Following compliance with this proposed rule, the total amount of other 
metal discharges from POTWs nationwide to surface waters will be 
approximately 20 lbs or a reduction of 1,257 lbs. See TEDD for more 
details.
---------------------------------------------------------------------------

    \27\ Dissolved mercury accounts for a portion of surface water 
discharges, because amalgam separators do not remove dissolved 
mercury.
---------------------------------------------------------------------------

XVIII. Cost Effectiveness

    EPA also conducted an analysis of the cost-effectiveness of the 
proposed option. For more information about the methodology, data, and 
results see the cost effectiveness section of the TEDD. The results of 
this cost-effectiveness analysis are expressed in terms of the costs 
(in 1981 dollars) per pound-equivalent removed, where pounds-equivalent 
removed for a particular pollutant is determined by multiplying the 
number of pounds of a pollutant removed by an option by a toxic 
weighting factor (TWF). The toxic weighting factors account for the 
differences in toxicity among pollutants and are derived using chronic 
aquatic life criteria (or toxic effect levels) and human health 
criteria (or toxic effect levels) established for the consumption of 
fish. For this proposal, EPA used the annual pounds removed for 
mercury, silver, tin, copper and zinc. The TWF for these pollutants is 
shown in Table XVIII-1.

 Table XVIII-1--Toxic Weighting Factors for Pollutants in Dental Amalgam
------------------------------------------------------------------------
 
------------------------------------------------------------------------
Total Mercury................................................     117.12
Silver.......................................................      16.47
Tin..........................................................       0.30
Copper.......................................................       0.63
Zinc.........................................................       0.05
------------------------------------------------------------------------

    EPA presents cost effectiveness in 1981 dollars as a reporting 
convention. This allows EPA to compare the cost-effectiveness of 
various ELGs. EPA calculates cost-effectiveness as the ratio of pre-tax 
annualized costs of an option to the annual pounds-equivalent removed 
by that option, and for this proposal is expressed as the average cost-
effectiveness for the option. Average cost-effectiveness can be thought 
of as the ``increment'' between no regulation and the selected option 
for any given rule. The technology basis for PSES in this proposal has 
a cost-effectiveness ratio of $181-$201/lb-equivalent. This cost-
effectiveness ratio falls within industry comparisons of PSES cost-
effectiveness. A review of approximately 25 of the most recently 
promulgated or revised categorical pretreatment standards demonstrates 
that PSES cost effectiveness ranges from approximately $1/lb-equivalent 
(Inorganic Chemicals) to $380/lb-equivalent (Transportation Equipment 
Cleaning) in 1981 dollars.

                                 Table XVIII-2--PSES Cost Effectiveness Analysis
----------------------------------------------------------------------------------------------------------------
                                                                Pre-tax total
                       Proposed option                            annualized     Removals (lbs-    Average cost
                                                               costs ($1981 M)        eq)         effectiveness
----------------------------------------------------------------------------------------------------------------
ADA National Survey..........................................              $23          113,152             $201
Colorado Survey..............................................               21          113,152              181
----------------------------------------------------------------------------------------------------------------


[[Page 63277]]

XIX. Environmental Assessment

A. Environmental Impacts

    EPA conducted a literature review concerning potential 
environmental impacts associated with mercury in dental amalgam 
discharged to surface water by POTWs. See DCN DA00148. Studies indicate 
that dental offices are the largest source of mercury entering POTWs. 
The total annual baseline discharge of dental mercury to POTWs is 
approximately 8,800 pounds (4.4 tons): 8,448 pounds are in the form of 
solid particles and 352 pounds (4%) are dissolved in the wastewater. 
Through POTW treatment, approximately 90% of dental mercury is removed 
from the wastewater and transferred to sewage sludge. The 10% of dental 
mercury not removed by POTW treatment is discharged to surface water. 
EPA estimates that POTWs annually discharge approximately 880 pounds of 
dental mercury nationwide.
    The CWA regulations known as Standards for Use and Disposal of 
Sewage Sludge, 40 CFR part 503, control the land application, surface 
disposal, and incineration of sewage sludge generated by POTWs. Of the 
11.2 billion dry pounds of sewage sludge generated annually, about 60%, 
or 6.7 billion pounds, are treated to produce biosolids for beneficial 
use as a soil amendment and applied to about 0.1% of agricultural lands 
in the United States (National Research Council, 2002). Approximately 
4,800 pounds per year of dental mercury are contained in land applied 
biosolids.
    Approximately 18%, or 2 billion pounds, of the sewage sludge 
generated annually by POTWs are surface disposed in facilities such as 
sewage sludge mono-fills or municipal landfills. Approximately 1,400 
pounds per year of dental mercury are contained in surface disposed 
sewage sludge. Pollutant limits and monitoring requirements for surface 
disposed sewage sludge mono-fills are set by 40 CFR part 503 and by 40 
CFR part 258 for municipal landfills. There may be additional state or 
local regulations that are more stringent than the federal biosolids 
regulations.
    The remaining 22%, or 2.5 billion pounds, of sewage sludge 
generated annually by POTWs is disposed of through incineration. An 
estimated 35 pounds of dental mercury are emitted to the atmosphere 
annually from incineration of sewage sludge (U.S. EPA, 2005); about 
11.5 pounds of which are deposited within the conterminous United 
States (U.S. EPA, 1997). 40 CFR part 503, subpart E sets requirements 
for the incineration of mercury and other toxic metals in sludge. For 
mercury, subpart E provides that incineration of sludge must meet the 
requirements of the National Emissions Standards for Mercury in subpart 
E of 40 CFR part 61.
    Environmental assessment of impacts associated with POTW discharges 
of dental mercury is complicated by uncertainties about the fate and 
transport of mercury in aquatic environments. The elemental form of 
mercury used in dentistry has low water solubility and is not readily 
absorbed when ingested by humans, fish, or wildlife. However, elemental 
mercury may be converted into highly toxic methylmercury in aquatic 
environments by certain forms of anaerobic sulfur reducing bacteria. 
Methylmercury is easily absorbed into muscle and fat tissues, but it is 
not readily excreted due to its low water solubility. Methylmercury 
thus has high potential to become increasingly concentrated up through 
aquatic food chains as larger fish eat smaller fish. Fish commonly 
eaten by humans may have methylmercury levels 100,000 times that of 
ambient water. The neurological effects of consumption of methylmercury 
contaminated fish are well documented. Developmental effects to 
fetuses, infants, children, and women of childbearing age are of 
special concern. Neurological effects from predation of methylmercury 
contaminated fish have been documented to occur in wild populations of 
fish, birds, and mammals in many areas of the United States. A 
plausible link has been identified between anthropogenic sources of 
mercury in the United States and methylmercury in fish. However, fish 
methylmercury concentrations also result from existing background 
concentrations of mercury which may consist of mercury from natural 
sources, mercury re-emitted from the oceans or soils, and mercury 
deposited in the United States from sources in other countries. Given 
the current scientific understanding of the environmental fate and 
transport of mercury, it is not possible to quantify how much of the 
methylmercury in fish consumed by the U.S. population is contributed by 
U.S. emissions relative to international mercury sources or natural 
mercury sources.
    EPA was unable to assess the specific environmental impacts of 
dental mercury discharged by POTWs due to insufficient data needed to 
evaluate several fundamental factors about the discharge, fate, and 
transport of dental mercury in aquatic environments, including: the 
degree and geographic extent of dental mercury methylation in aquatic 
environments, the amount of methylated dental mercury that is taken up 
by fish and wildlife, the human consumption rates of fish contaminated 
with methylated dental mercury, and the extent and magnitude of 
naturally-occurring mercury in aquatic environments.

B. Environmental Benefits

    While EPA did not perform an environmental benefits analysis of 
this proposed rule, due to insufficient data about the aquatic fate and 
transport of dental mercury discharged by POTWs, EPA was able to assess 
the qualitative environmental benefits based on existing information. 
For example, EPA identified studies that show that decreased point-
source discharges of mercury to surface water result in lower 
methylmercury concentrations in fish. Moreover, several studies 
quantified economic benefits from improved human health and ecological 
conditions resulting from lower fish concentrations of methylmercury. 
See DCN DA00148. The proposed pretreatment standards will produce human 
health and ecological benefits by reducing the estimated annual 
nationwide POTW discharge of dental mercury to surface water from 880 
pounds to 14 pounds.

XX. Non-Water Quality Environmental Impacts Associated With the 
Proposed Technology Basis

    Eliminating or reducing one form of pollution may cause other 
environmental problems. Sections 304(b) and 306 of the Clean Water Act 
require EPA to consider non-water quality environmental impacts 
(including energy requirements) associated with effluent limitations 
guidelines and standards. To comply with these requirements, EPA 
considered the potential impact of the collection and treatment 
technologies on energy consumption, air pollution, and solid waste 
generation. EPA anticipates that the proposed rule would produce 
minimal non-water quality impacts. The Administrator has determined 
that these very minimal impacts are acceptable. For additional 
information on the analysis of these non-water quality impacts, see the 
Technical and Economic Development Document.

A. Energy Requirements

    Net energy consumption considers the incremental electrical 
requirements associated with operating and maintaining dental amalgam 
separators used in combination with BMPs that form the technology basis 
for the proposed rule standards. As described in Section VI, an amalgam 
separator in

[[Page 63278]]

a dental office is installed between chairs used for treatment and the 
vacuum pump. Amalgam separators use sedimentation, either alone or in 
conjunction with filtration to remove solids in the waste stream. Most 
separators rely on gravity or the suction of the existing vacuum system 
to operate, and do not require an additional electrical power source. 
As a result, EPA expects operation of an amalgam separator would pose 
negligible additional energy requirements on the existing vacuum pump.
    While the vendor data used to support this proposed rule have not 
identified incremental energy requirements for an amalgam separator, 
EPA is aware that some units described in the literature may require 
small pumps to remove settled effluent from the separator (DCN 00162). 
EPA found that these pumps are designed to operate only at the end of 
the day or overnight, when the vacuum system is turned off. Any 
incremental energy requirements in those cases where a small 
supplemental pump is installed would be negligible compared to the 
energy demands of the vacuum pump. Based on this evaluation of energy 
requirements associated with this proposed rule, EPA concludes there 
will be no significant non-water quality impacts associated with the 
energy requirements of this proposed rule.

B. Air Emissions

    Unbound mercury is highly volatile and can easily evaporate into 
the atmosphere. An estimated 99.6% of dental mercury discharges are in 
solid bound form; i.e. elemental mercury bound to amalgam particles 
(DCN DA00018). Because the majority of dental mercury is bound to solid 
particles, it likely will not volatize to the atmosphere. Therefore, 
EPA expects the proposed PSES and PSNS will not pose any increases in 
air pollution. EPA concludes there will be no significant non-water 
quality impacts associated with air emissions as a result of this 
proposed rule.

C. Solid Waste Generation

    As explained above in Section XI, in the absence of amalgam 
separators, a portion of the amalgam rinsed into chair side drains is 
collected by chair side traps. The remainder is discharged to the POTW 
where the vast majority is removed from the wastewater and becomes part 
of the POTW sludge that may be land applied, disposed of in landfills 
or mono-fills, or incinerated. This proposed rule is expected to 
increase the use of amalgam separators nationwide by one and a half 
times, since EPA estimates 40% of dental offices have separators 
installed, with a corresponding increase in collection of used amalgam 
prior to POTW discharge and recycling of amalgam via the spent 
separator canisters. EPA expects the operation and maintenance 
requirements associated with the amalgam separator compliance option 
included as part of the proposed rule will further promote recycling as 
the primary means of amalgam waste management. EPA expects this 
proposed rule will not create additional solid waste, but will instead 
result in a shift in how dental amalgam is handled. Nationally, EPA 
expects less dental amalgam will partition to the POTW wastewater 
sludge leading to reductions in the amount of mercury currently land 
applied, landfilled, or released to the air during incineration. 
Instead, it will be collected in separator canisters and recycled. 
Based on this evaluation of solid waste generation, EPA concludes there 
will be a reduction in non-water quality impacts associated with solid 
waste generation as a result of this proposed rule.

XXI. Implementation and Proposed Changes to General Pretreatment 
Regulations in 40 CFR Part 403

A. Implementation Deadline

1. Existing Sources
    For existing sources, EPA proposes a compliance date of three years 
after the effective date of the final rule. Section 307(b)(1) of the 
CWA provides categorical pretreatment standards ``shall specify a time 
for compliance not to exceed three years from the date of 
promulgation.'' See also 40 CFR 403.6(b). In proposing a compliance 
date for existing sources subject to this proposed rule, EPA considered 
several factors. First, EPA considered the burden on Control 
Authorities (POTWs with approved Pretreatment Programs) of implementing 
this rule on an industry consisting of approximately 110,000 dental 
offices, many of whom are small businesses. EPA expects that these 
POTWs will need to develop and implement new strategies and programs 
for managing the enforcement and compliance of these pretreatment 
standards given that the number of possibly affected facilities is 
approximately 10 times the total number of dischargers currently 
regulated under any categorical pretreatment standard. EPA expects that 
POTWs will need time to conduct outreach to dental offices subject to 
this proposed rule. Moreover, EPA envisions that dental offices may use 
the entire three year period to come into compliance with the numeric 
standard (presumably using amalgam separators) and implement the 
required BMPs.
2. New Sources
    For new sources, the compliance deadline is governed by EPA's 
regulation at 40 CFR 403.6(b), which provides that

    New Sources shall install and have in operating condition, and 
shall `start-up' all pollution control equipment required to meet 
applicable Pretreatment Standards before beginning to Discharge. 
Within the shortest feasible time (not to exceed 90 days), new 
Sources must meet all applicable Pretreatment Standards.

B. Upset and Bypass Provisions

    A ``bypass'' is an intentional diversion of the streams from any 
portion of a treatment facility. An ``upset'' is an exceptional 
incident in which there is unintentional and temporary noncompliance 
with technology-based permit effluent limitations because of factors 
beyond the reasonable control of the permittee. EPA's regulations for 
indirect dischargers concerning bypasses and upsets are set forth at 40 
CFR 403.16 and 403.17.

C. Variances and Modifications

    The CWA requires application of pretreatment standards established 
pursuant to sections 304 and 307 for all indirect dischargers. However, 
the statute provides for the modification of these national 
requirements in a limited number of circumstances. Moreover, the Agency 
has established administrative mechanisms to provide an opportunity for 
relief from the application of the national pretreatment standards for 
categories of existing sources.
1. Fundamentally Different Factors Variance
    EPA may develop pretreatment standards different from the otherwise 
applicable requirements if an individual discharger is fundamentally 
different with respect to factors considered in establishing the 
standards applicable to the individual discharger. Such a modification 
is known as a ``fundamentally different factors'' (FDF) variance. See 
40 CFR 403.13. EPA, in its initial implementation of the effluent 
guidelines and standards program, provided for the FDF modifications in 
regulations. These were variances from the BCT effluent limitations, 
BAT limitations for toxic and nonconventional pollutants, and BPT 
limitations for conventional pollutants for direct dischargers. FDF 
variances for toxic pollutants were challenged judicially and 
ultimately sustained by

[[Page 63279]]

the Supreme Court. (Chemical Manufacturers Association v. Natural 
Resources Defense Council, 479 U.S.C. 116 (1985)).
    Subsequently, in the Water Quality Act of 1987, Congress added new 
CWA section 301(n). This provision explicitly authorizes modifications 
of the otherwise applicable BAT effluent limitations or categorical 
pretreatment standards for existing sources if a discharger is 
fundamentally different with respect to the factors specified in CWA 
section 304 or 403 (other than costs) from those considered by EPA in 
establishing the effluent limitations or pretreatment standards. CWA 
section 301(n) also defined the conditions under which EPA may 
establish alternative requirements. Under section 301(n) of the CWA, an 
application for approval of a FDF variance must be based solely on (1) 
information submitted during rulemaking raising the factors that are 
fundamentally different or (2) information the applicant did not have 
an opportunity to submit. The alternate limitation or standard must be 
no less stringent than justified by the difference and must not result 
in markedly more adverse non-water quality environmental impacts than 
the national limitation or standard.
    EPA regulations at 40 CFR part 403, authorizing the Regional 
Administrators to establish alternative standards, further detail the 
substantive criteria used to evaluate FDF variance requests for 
existing dischargers to POTWs. Thus, 40 CFR 403.13(d) identifies six 
factors (e.g., volume of process wastewater, age and size of a 
discharger's facility) that may be considered in determining if a 
discharger is fundamentally different. The Agency must determine 
whether, based on one or more of these factors, the discharger in 
question is fundamentally different from the dischargers and factors 
considered by EPA in developing the nationally applicable pretreatment 
standards. The regulation also lists four other factors (e.g., 
inability to install equipment within the time allowed or a 
discharger's ability to pay) that may not provide a basis for an FDF 
variance. In addition, under 40 CFR 403.13(c)(2), a request for 
standards less stringent than the national standard may be approved 
only if compliance with the pretreatment standards would result in 
either (a) a removal cost wholly out of proportion to the removal cost 
considered during development of the pretreatment standards, or (b) a 
non-water quality environmental impact (including energy requirements) 
fundamentally more adverse than the impact considered during 
development of the pretreatment standards. The legislative history of 
section 301(n) of the CWA underscores the necessity for the FDF 
variance applicant to establish eligibility for the variance. EPA's 
regulations at 40 CFR 403.13 are explicit in imposing this burden upon 
the applicant. The applicant must show that the factors relating to the 
discharge controlled by the applicant's permit which are claimed to be 
fundamentally different are, in fact, fundamentally different from 
those factors considered by EPA in establishing the applicable 
pretreatment standards. In practice, very few FDF variances have been 
granted for past ELGs. An FDF variance is not available to a new source 
subject to PSNS.
2. Economic Variances
    Section 301(c) of the CWA authorizes a variance from the otherwise 
applicable PSES and PSNS for nonconventional pollutants due to economic 
factors. As this rule controls toxic pollutants and only controls 
nonconventional pollutants that are also found in the same waste 
stream, this variance would not be applicable to this particular rule.

D. What are the roles of key entities involved in implementing the rule 
and how are pretreatment standards implemented?

    EPA recognizes the role of many interested parties in the 
development of, and, ultimately, the successful implementation of 
pretreatment standards for dental dischargers. To the greatest extent 
possible, EPA has attempted to strike a reasonable balance among the 
many interests. A short summary of the various roles involved in 
implementing categorical pretreatment standards is provided below.
1. Control Authorities
    The ``Control Authority'' refers to the POTW if the POTW has an 
approved Pretreatment Program, or the Approval Authority if it has not 
been approved, which may be the state or EPA. A POTW is a treatment 
works as defined by section 212(2) of the CWA, which is owned by a 
state or municipality (as defined in CWA sections 502 (3) and (4), 
respectively). (see 40 CFR 403.3(q).) POTWs collect wastewater from 
homes, commercial buildings, and industrial facilities and typically 
transport it via a series of pipes, known as a collection system, to 
the treatment plant. Most POTWs are not designed to treat the toxics in 
commercial and industrial wastes, which can cause pass through, 
interfere with, or are otherwise incompatible with the operation of 
POTWs, including sludge disposal methods at POTWs. The General 
Pretreatment Regulations require POTWs that meet certain criteria (e.g. 
minimum design flow) to develop Pretreatment Programs to control 
industrial Discharges into their sewage collection systems, unless the 
state exercises its option to assume local responsibilities as provided 
in EPA's regulations at 40 CFR 403.10(e) and (f). Today there are an 
estimated 1500 approved POTW Pretreatment Programs. As required under 
40 CFR part 403, Control Authorities implement and enforce control 
mechanisms (e.g., permits) to the Industrial Users (IUs) that discharge 
to their systems, inspect and sample, and enforce control requirements 
in order to protect the POTW against discharges which ``pass through'' 
or cause interference'' with the POTW (see 40 CFR 403.3(p) and (k)).
2. Approval Authority
    The Director in an NPDES state with an approved state Pretreatment 
Program may be authorized to serve as the Approval Authority for the 
implementation of a general pretreatment program. (40 CFR 403.3(c)). 
Thirty-six states have such approved Pretreatment Programs and are 
authorized to serve as Approval Authorities for implementation of the 
Pretreatment Program. In a non-NPDES state or an NPDES state without an 
approved state Pretreatment Program, the EPA Regional Administrator is 
the Approval Authority.
3. EPA
    EPA establishes and implements national regulations for 
Pretreatment Programs and categorical pretreatment standards for 
certain industries such as the pretreatment standards for dental 
amalgam proposed today. EPA also develops policy and guidance and 
provides training and oversight for Pretreatment Program 
implementation. As noted above, EPA's Regional Administrator serves as 
the Approval Authority for a non-NPDES state or an NPDES state without 
an approved state Pretreatment Program, and as the Control Authority 
for POTWs without an approved Pretreatment Program in these states.
4. Industrial Dischargers (i.e. Dentists)
    IUs of POTWs must comply with Pretreatment Standards prior to 
introducing pollutants into a POTW. The General Pretreatment 
Regulations include general prohibitions that forbid IUs from causing 
pass through and interference (i.e., cause the POTW to

[[Page 63280]]

violate its permits limits, or interfere with the operation of the POTW 
or the beneficial use of its sewage sludge), and specific prohibitions 
against the discharge of pollutants that cause problems at the POTW 
such as corrosion, fire or explosion, and danger to worker health and 
safety. As discussed in this document, EPA may also develop national 
categorical pretreatment standards, including numeric pollutant limits 
and BMPs, for IUs in specific industrial categories. The General 
Pretreatment Regulations include reporting and other requirements 
necessary to implement these categorical standards (e.g., 40 CFR 
403.12).

E. What are the Control Authority requirements under existing General 
Pretreatment Regulations?

    The current regulations require certain minimum oversight of IUs by 
Control Authorities, which are typically POTWs with Approved 
Pretreatment Programs but could be states or EPA acting as Pretreatment 
Control Authorities. The required minimum oversight includes receipt 
and analysis of reports and other notices submitted by IUs, randomly 
sampling and analyzing effluent from IUs, and conducting surveillance 
activities to identify occasional and continuing non-compliance with 
pretreatment standards. In addition, for IUs designated as significant 
industrial users (SIUs), per 40 CFR 403.3(v), Control Authorities must 
inspect and sample the SIU effluent annually, review the need for a 
slug control plan, and issue a Permit or equivalent control mechanism 
with a duration not to exceed five years (40 CFR 403.8(f)(1)(iii) and 
403.8(f)(2)(v), 403.10(e) and 403.10(f)(2)(i)). Control authorities may 
determine that an industrial user is a non-significant categorical 
industrial user or that an industrial user is not an SIU (see 40 CFR 
403.3(v)(2) and (v)(3)).
    Facilities that are subject to categorical pretreatment standards 
contained in regulations in 40 CFR Chapter I, subchapter N are referred 
to as Categorical Industrial Users (CIUs). The regulations related to 
SIU at 40 CFR 403.3(v) define SIU to include CIUs, but also provide 
that a Control Authority may determine that a CIU may be a Non-
Significant Categorical Industrial User (NSCIU) if certain conditions 
are met. (see 403.3(v)(1) and (v)(2)). State Approval Authorities and 
POTW Control Authorities who have the legal authority to implement the 
NSCIU classification may find some of their CIUs satisfy the qualifying 
conditions of NSCIU at 40 CFR 403.3(v)(2). Upon such finding, the 
Control Authority may exclude facilities meeting the NSCIU criteria 
from the SIU definition and its minimum oversight requirements. A 
Control Authority may not exclude CIUs from the requirements of the 
categorical pretreatment standards.

F. Why is EPA revising the existing General Pretreatment Regulations?

    EPA proposes to amend selected parts of the General Pretreatment 
Regulations in order to simplify oversight requirements for the 
approximately 110,000 dental offices subject to this proposed rule. As 
mentioned in paragraph E. of this section, when EPA promulgates 
categorical industrial pretreatment standards, as defined in 40 CFR 
part 403, affected dischargers are referred to as Categorical 
Industrial Users (CIUs). The number of dental offices that would be 
subject to this proposed rule is approximately ten times the current 
number of Categorical Industrial Users. EPA recognizes regulatory 
oversight of this increased number of CIUs would need to be very 
different from regulating the current number of CIUs. Using the 
existing regulatory framework, enforcement of categorical pretreatment 
regulation on this industry would require an increase in local, state 
and federal resources whereas EPA does not expect such efforts to 
result in greater environmental benefit. EPA is focused on providing 
technical means to reduce administrative burden to dentists and Control 
Authorities, while still providing a clear understanding of who is 
affected and what they are expected to do, as well as achieving the 
projected pollutant reductions. EPA estimates that these changes to the 
Existing General Pretreatment Standards would reduce costs to POTWs to 
implement and enforce this proposed rule by $47 million annually (see 
TEDD).

G. What changes is EPA proposing to the General Pretreatment Standards?

    EPA proposes a new classification of CIU specifically tailored to 
the Dental Office Effluent Limitations Guidelines and Standards rule, 
``Dental Industrial User'' (DIU). EPA proposes that such Users not be 
subject to the oversight requirements for SIUs (i.e., control mechanism 
issuance requirement, annual inspection and sampling requirements). 
Rather, EPA proposes to allow Control Authorities to focus their 
oversight efforts on those dental office facilities that fail to meet 
the compliance requirements of the DIU.

H. When is a dental office a DIU?

    Under the proposed rule, a dental discharger is given the option of 
complying with monitoring and reporting requirements in 40 CFR 441.60, 
which are tailored for dental dischargers, in lieu of the otherwise 
applicable monitoring and reporting requirements in 40 CFR part 403. If 
a dental discharger complies with (1) the special monitoring and 
reporting requirements in 40 CFR 441.60, (2) the remaining 40 CFR part 
403 requirements, and the applicable pretreatment standards (PSES or 
PSNS), then the Control Authority may treat the dental discharger as a 
DIU. The DIU must maintain compliance in order to retain its DIU 
status.

I. When is a dental office not a DIU?

    If the dental office does not meet the requirements to be treated 
as a DIU, under this proposal the Control Authority must treat the 
dental discharger as a Significant Industrial User as defined in 40 CFR 
403.3(v). As a Significant Industrial User, the POTW Control Authority 
would be required to conduct the oversight duties applicable to SIUs as 
described in 40 CFR 403.8(f).

J. What oversight responsibilities for DIUs is EPA proposing for 
Control Authorities?

    This proposal would require that a Control Authority evaluate, at 
least once per year, whether an IU previously determined to be a DIU 
still meets the criteria for treatment as a DIU under 40 CFR 441.60. 
EPA anticipates that this evaluation will primarily involve the Control 
Authority's verification that the certification has been submitted by 
the dental office documenting continued eligibility for DIU status. In 
accordance with 40 CFR 403.8(f)(2)(viii)(F), a dental discharger would 
be in significant noncompliance if it fails to provide any required 
report within 45 days of the due date or if the Control Authority 
elects to inspect the facility and finds the facility is not in 
compliance with 40 CFR 441.60. Upon discovery that a dental office is 
not in compliance with regulations at 40 CFR 441.60 (either reporting 
requirements, 403, or 441 PSES/PSNS requirements), the Control 
Authority must initiate enforcement in accordance with its approved 
Pretreatment Program to return the dental discharger into compliance. 
In order for the Control Authority to continue to treat the dentist as 
a DIU, the Control Authority would need to verify and find, through an 
inspection, that the dental discharger has returned to full compliance 
with the criteria in 40

[[Page 63281]]

CFR 441.60. If, within 90 days, the Control Authority inspects, 
verifies, and finds that the dental discharger has returned to full 
compliance with 40 CFR 441.60, then the dental discharger would remain 
a DIU. The 90 day compliance deadline is consistent with other portions 
of 40 CFR part 403 (e.g., significant noncompliance compliance report 
deadlines, 90 day report after effective dates of categorical 
standards), and provides both the dental discharger and Control 
Authority with an incentive to provide a timely return to compliance. 
If the dental discharger has not returned to compliance within 90 days 
of the initial noncompliance, the Control Authority could no longer 
treat the dental discharger as a DIU and the dental discharger would 
become a Significant Industrial User. Control Authorities are required 
to provide oversight of SIUs which includes inspection and sampling of 
each SIU annually, reviewing the need for a slug control plan, and 
issuing a Permit or equivalent control mechanism with a duration not to 
exceed five years (40 CFR 403.8(f)(1)(iii) and (f)(2)(v) and 
403.10(f)(2)(i)).

K. Can a dental office DIU be a Non-Significant Industrial User 
(NSCIU)?

    EPA does not propose to prohibit a Control Authority from finding 
that a dental office may qualify as an NSCIU on an individual basis. 
State Approval Authorities and POTW Control Authorities who have the 
legal authority to implement the NSCIU classification may find that one 
or more of their dental office CIUs may qualify as NSCIUs. However, 
since its promulgation in 2005, many state Approval Authorities and 
POTW Control Authorities have not adopted regulations to implement the 
NSCIU classification. EPA believes that the DIU classification, 
tailored for this single categorical pretreatment standard, while 
comparable to the NSCIU classification, would be preferable, because it 
would significantly reduce the Control Authority's burden in complying 
with the oversight requirements that would otherwise apply.

L. Can Dental Industrial Users be covered under a general permit?

    Although this proposed rule does not require a Control Authority to 
regulate DIUs as SIUs thereby requiring the Control Authority to issue 
a control mechanism, designation of a dental office subject to 40 CFR 
part 441 as a DIU does not preclude a Control Authority's option to 
regulate the dental office under a general control mechanism, 40 CFR 
403.8(f)(1)(iii)(A), if that legal authority is adopted. The General 
Pretreatment Regulations describe conditions which must be met in order 
for the Control Authority to use a general control mechanism in lieu of 
an individual permit or control mechanism. Provided that the Control 
Authority adopted the necessary legal authority and modified its 
Pretreatment Program to incorporate such authority and procedures, the 
Control Authority may use a general control mechanism or ``general 
permit'' for facilities that meet certain minimum criteria for being 
considered substantially similar. The use of general control mechanisms 
allows the permitting authority to allocate resources in a more 
efficient manner and to provide timelier permit coverage, particularly 
in the circumstances of covering large numbers of similar facilities 
under a single mechanism. EPA considers that most dental offices 
generally will conform to these requirements and could appropriately be 
covered by a general control mechanism issued by a Control Authority. 
The use of a general control mechanism also ensures consistency of 
permit conditions for similar facilities. Additional information on the 
use of general control mechanisms may be found in the Federal Register 
of October 14, 2005 (70 FR 60143).

M. Would any POTW with a dentist office in its service area be required 
to develop a Pretreatment Program?

    In accordance with 40 CFR 403.8(a), POTWs (or combination of POTWs 
operated by the same authority) with a total design flow greater than 5 
million gallons per day and receiving pollutants from IUs which pass 
through or interfere with the operation of the POTW or are otherwise 
subject to Pretreatment Standards are required to establish a POTW 
Pretreatment Program unless the state with an approved Pretreatment 
Program exercises its option to assume local responsibilities as 
provided for in 40 CFR 403.10(e). For smaller POTWs, POTWs that have a 
design flow of 5 million gallons per day or less, the Regional 
Administrator or state Director may require the POTW to develop a local 
Pretreatment Program if the nature or volume of the industrial 
influent, treatment process upsets, violations of POTW effluent 
limitations, contamination of municipal sludge, or other circumstances 
warrant such development in order to prevent interference or pass 
through. Interference and pass through are defined at 40 CFR 403.3(k) 
and (p), respectively. As noted above, a state with an Approved state 
Pretreatment Program may instead assume local responsibilities as 
provided in 40 CFR 403.10(e). EPA anticipates that the approved states 
will choose to carry out the oversight activities themselves rather 
than requiring a POTW to develop a full Pretreatment Program solely to 
regulate its dental dischargers.

N. Would states or municipalities that already implement Dental Amalgam 
Control Programs need to modify their regulations?

    The proposed rulemaking would not affect existing state and local 
requirements that control discharges of dental amalgam. However, states 
with approved state programs and POTWs with approved Pretreatment 
Programs would need to enforce the federal requirements at a minimum. 
The new federal requirements include removal of at least 99.0% of total 
mercury from amalgam discharges which can be accomplished through 
proper use of a 2008 ISO 11143 certified amalgam separator with a 
removal efficiency of at least 99.0%. The proposal at part 441.40(d) 
would allow dentists currently operating amalgam separators no less 
efficient than 95% to continue to operate their separators for ten 
years before they would be required to meet the 99% removal standard. 
Where ongoing state or POTW Control Authority programs require 
additional information or implementation requirements, the Control 
Authority must implement and enforce both program requirements and, for 
overlapping requirements, the more stringent of the two programmatic 
requirements.

O. Will states or municipalities that already implement Dental Amalgam 
Control Programs need to issue control mechanisms or permits to impose 
requirements that are more stringent than the federal requirements?

    The legal authority requirements for a POTW Pretreatment program 
only require issuance of an individual or general control mechanism to 
SIUs, 40 CFR 403.8(f)(2)(1)(iii)(A). The proposed regulation 
modification in the General Pretreatment Regulations is to establish a 
new DIU classification of Industrial User. The proposal indicates that 
a DIU will not be a Significant Industrial User. Where the state or 
POTW existing dental amalgam control programs are equal to or less 
stringent than this proposal, and the state or Control Authority adopt 
and have their Pretreatment Programs appropriately approved to 
incorporate EPA's DIU provisions, dental offices compliant

[[Page 63282]]

with the DIU classification will not need to be issued a control 
mechanism.

P. What reports would dental dischargers be required to submit?

    Existing and new dental dischargers could comply with the special 
reporting requirements in 40 CFR part 441 in lieu of the otherwise 
applicable reporting requirements in 40 CFR part 403 by submitting the 
Baseline Report (40 CFR 441.60(a)(1)) and the 90 Day Compliance Report 
(40 CFR 441.60(a)(2)) and Periodic Monitoring reports (40 CFR 
441.60(a)(3)). Submission of these reports would satisfy the reporting 
requirements in 40 CFR parts 403 and 441. Dental dischargers who do not 
submit reports consistent with the requirements in 40 CFR 441.60 would 
be required to submit the reports described in 40 CFR 403.12(b), (d), 
and (e).

Q. Can the DIU designate a contractor or contract vendor to submit 
Compliance Reports to the Control Authority or EPA?

    In accordance with 40 CFR 403.12(l), Baseline Monitoring Reports, 
90-day Compliance Reports, and Periodic monitoring reports (40 CFR 
403.12(b), (d), and (e), respectively) must be signed by (1) a 
responsible corporate officer of the IU if it is a corporation; (2) a 
general partner or proprietor if the IU is a partnership or sole 
proprietorship; or (3) a duly authorized representative of the 
responsible corporate officer, general partner, or proprietor if the 
authorization specifies either an individual or a position having 
responsibility for the overall operation of the facility from which the 
industrial discharge originates, such as the position of plant manager 
or a position of equivalent responsibility for environmental matters 
for the company and the written authorization is submitted to the 
Control Authority.\28\ This does not preclude a third-party from 
submitting the reports as long as the submission includes the proper 
signature from the DIU.
---------------------------------------------------------------------------

    \28\ Today's proposal does not apply to third-party vendors 
because they are not dental dischargers, and therefore, as such, EPA 
cannot compel a third-party vendor to meet any reporting 
requirements.
---------------------------------------------------------------------------

R. Would Control Authorities need to modify their Sewer Use Ordinance 
and state regulations, respectively, to incorporate these changes to 40 
CFR part 403?

    The proposed changes to 40 CFR part 403 to create the DIU 
classification are changes that the Control Authority may adopt at its 
discretion. The changes to 40 CFR part 403 provide program flexibility 
and are not required to be incorporated into the state or POTW's 
Pretreatment Program. However, for Control Authorities to designate 
dental offices as DIUs, the state and POTW Pretreatment program would 
need to incorporate these changes into their legal authority under 40 
CFR 403.8(f)(l).

XXII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
action is a ``significant regulatory action.'' Accordingly, EPA 
submitted this action to the OMB for review under Executive Orders 
12866 and 13563 (76 FR 3821, January 21, 2011) and any changes made in 
response to OMB recommendations have been documented in the docket for 
this action.

B. Paperwork Reduction Act

    The information collection requirements in this proposed rule have 
been submitted for approval to the OMB under the Paperwork Reduction 
Act, 44 U.S.C. 3501 et seq. The Information Collection Request (ICR) 
document prepared by EPA has been assigned EPA ICR number 2514.01. To 
reduce the overall costs associated with this rule, in lieu of 
discharge monitoring, proposed 40 CFR 441.60 allows dentists to certify 
compliance with requirements for amalgam capture and certain BMPs.
    For purposes of this estimate, EPA assumed all affected dentists 
would elect to comply with this proposal through certification rather 
than discharge monitoring. EPA estimates it would take a total annual 
average of 153,000 hours \29\ and $2.5 million for affected dental 
offices to collect and report the information required for 
certification in the proposed rule. This estimate includes effort for 
each dental office associated with completing the baseline monitoring 
report, a one-time compliance report and an annual compliance 
certification for each year of a three year ICR. This estimate is based 
on average labor rates from the Bureau of Labor Statistics for the 
dental office personnel involved in collecting and reporting the 
information required. EPA estimates it would take a total annual 
average of 17,400 hours and $960,000 for control authorities to review 
the information submitted by dentists that certify they meet the 
requirements in the proposed rule. EPA estimates that there would be no 
start-up or capital costs associated with the information described 
above. Burden is defined at 5 CFR 1320(b).
---------------------------------------------------------------------------

    \29\ This estimate reflects approximately three hours per office 
in the first year and one hour each subsequent year.
---------------------------------------------------------------------------

    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations in 40 CFR are listed in 40 CFR part 9.
    To comment on the Agency's need for this information, the accuracy 
of the provided burden estimates, and any suggested methods for 
minimizing respondent burden, EPA has established a public docket for 
this proposed rule, which includes this ICR, under Docket 
identification ID number EPA-HQ-OW-2014-0693. Submit any comments 
related to the ICR to EPA and OMB. See ADDRESSES section in this 
document for where to submit comments to EPA. Since OMB is required to 
make a decision concerning the ICR between 30 and 60 days after October 
22, 2014, a comment to OMB is best assured of having its full effect if 
OMB receives it by November 21, 2014. The final rule will respond to 
any OMB or public comments on the information collection requirements 
contained in this proposal.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of this proposed rule on 
small entities, small entity is defined as: (1) A small business in the 
Dental Office sector (NAICS 621210) with annual receipts of 7 million 
dollars or less (based on SBA size standards); (2) a small governmental 
jurisdiction that is a government of a city, county, town, school 
district or special district with a population of less than 50,000; and 
(3) a small organization that is any not-for-profit enterprise which is 
independently owned and operated and is not dominant in its field.
    EPA estimates that 109,600 dental offices out of 109,859 dental 
offices potentially subject to this proposal meet the small business 
definition. EPA's analysis of projected impacts on small dental offices 
is described in detail in

[[Page 63283]]

Section XVI. EPA projects less than 1% of 109,859 affected dental 
offices would incur compliance costs exceeding 1% of revenue and no 
more than 0.2% would incur compliance costs exceeding 3% of revenue. 
After considering the economic impact of this proposed rule on small 
entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities.
    Although this proposed rule will not have a significant economic 
impact on a substantial number of small entities, EPA nonetheless has 
tried to reduce the impact of this proposed rule on small entities. 
First, while some amalgam separators currently used at some dentists 
are certified to meet slightly less mercury removal than required in 
this proposed rule (e.g., they are certified to remove 95% total 
mercury), this proposal would allow dentists with existing separators 
to satisfy the requirements for a period of up to 10 years. See Section 
XIV. In addition, this proposed rule includes a compliance option that 
would allow dental offices subject to the rule to certify proper 
operation of a widely available, inexpensive technology that meets 
certain requirements in combination with BMPs in lieu of conducting 
more onerous discharge monitoring requirements that would otherwise be 
associated with pretreatment standards. Finally, EPA has tried to 
minimize impacts to small governments responsible for Pretreatment 
Programs by proposing to amend the General Pretreatment Regulations to 
create the DIU classification. The DIU classification reduces oversight 
responsibilities for Control Authorities from the current regulatory 
scheme, while at the same time achieving the projected pollutant 
reductions. We continue to be interested in the potential impacts of 
the proposed rule on small entities and welcome comments on issues 
related to such impacts.

D. Unfunded Mandates Reform Act (UMRA)

    This proposed rule does not contain a Federal mandate that may 
result in expenditures of $100 million or more for state, local, and 
tribal governments, in the aggregate, or the private sector in any 1 
year. As explained in Section XVI, the annual cost of the proposed rule 
is $44-$49 million. Thus, this proposed rule is not subject to the 
requirements of sections 202 or 205 of UMRA.
    The proposal is also not subject to the requirements of section 203 
of UMRA, because it contains no regulatory requirements that may 
significantly or uniquely affect small governments. EPA has not 
identified any dental offices that are owned by small governments. 
While this proposal would impact government entities required to 
administer the proposed pretreatment standards, EPA does not expect 
that this would include any small governments. By statute, a small 
government jurisdiction is defined as a government of a city, county, 
town, school district or special district with a population of less 
than 50,000 (5 U.S.C. 601). As explained in Section XXI, control 
authorities are responsible for oversight and administration associated 
with this proposal. To qualify as a Control Authority, a POTW must have 
a flow of at least 5 million gallons per day. The average water use per 
person is 100 gallons per day so a POTW with a population less than 
50,000 would likely have a flow less than 5 MGD. Therefore, EPA does 
not expect small government owned POTWs would meet the definition of a 
Control Authority.

E. Executive Order 13132: Federalism

    This proposed rule would not have federalism implications. It would 
not have substantial direct effects on the states, on the relationship 
between the national government and the states, or on the distribution 
of power and responsibilities among the various levels of government, 
as specified in Executive Order 13132. The proposed rule would not 
alter the basic state-federal scheme established in the CWA under which 
EPA authorizes states to carry out the NPDES permit program. EPA 
expects the proposed rule would have little effect on the relationship 
between, or the distribution of power and responsibilities among, the 
federal and state governments. Thus, Executive Order 13132 does not 
apply to this proposed rule.
    EPA coordinated closely with states, via ECOS and local governments 
and with NACWA, throughout the development of this proposed rule. In 
the spirit of Executive Order 13132, and consistent with EPA policy to 
promote communications between EPA and state and local governments, EPA 
specifically solicits comment on this proposed rule from state and 
local officials.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This proposed rule does not have tribal implications, as specified 
in Executive Order 13175 (65 FR 67249, November 6, 2000). It would not 
have substantial direct effects on Tribal governments, on the 
relationship between the Federal government and Indian Tribes, or on 
the distribution of power and responsibilities between the Federal 
government and Indian Tribes. This proposed rule contains no Federal 
mandates for Tribal governments and does not impose any enforceable 
duties on Tribal governments. Thus, Executive Order 13175 does not 
apply to this rule. EPA specifically solicits additional comment on 
this proposed action from Tribal officials.

G. Executive Order 13045: Protection of Children From Environmental 
Health and Safety Risks

    Executive Order 13045 (62 FR 19885, April 23, 1997) applies to 
rules that are economically significant according to Executive Order 
12866 and involve a health or safety risk that may disproportionately 
affect children. This action is not subject to Executive Order 13045 
because it is estimated to cost less than $100 million and does not 
involve a safety or health risk that may have disproportionately 
negative effects on children. The proposed rule will reduce the amount 
of mercury from dental amalgam entering POTW's and eventually the 
nation's waters, which will reduce impacts to the neurological 
development of children.

H. Executive Order 13211: Energy Effects

    This proposed rule is not a ``significant energy action'' as 
defined in Executive Order 13211, ``Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use'' (66 FR 
28355, May 22, 2001) because it is not likely to have a significant 
adverse effect on the supply, distribution, or use of energy, as 
described in Section XX of this proposal. EPA determined that any 
additional energy usage would be insignificant to the total energy 
usage of Dental Offices and total annual U.S. energy consumption.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act (NTTAA) of 1995, (Pub. L. 104-113; 15 U.S.C. 272 note) directs EPA 
to use voluntary consensus standards in its regulatory activities 
unless to do so would be inconsistent with applicable law or otherwise 
impractical. Voluntary consensus standards are technical standards 
(e.g., materials specifications, test methods, sampling procedures, and 
business practices) that are developed or adopted by voluntary 
consensus standard bodies. The NTTAA directs EPA to provide Congress, 
through OMB, explanations when the Agency decides not to use available 
and applicable voluntary consensus standards.

[[Page 63284]]

    This proposed rulemaking involves technical standards. The 
International Organization for Standardization (ISO) developed 
efficiency standards for amalgam separators (ISO 11143) in 1999 and 
updated these standards in 2008. EPA proposes to use ISO 11143 2008. 
This voluntary standard setting organization established a standard for 
measuring amalgam separator efficiency by evaluating the retention of 
amalgam mercury using specified test procedures in a laboratory 
setting. It also includes requirements for instructions for use and 
operation and maintenance.
    EPA welcomes comments on this aspect of the proposed rulemaking 
and, specifically, invites the public to identify potentially-
applicable voluntary consensus standards and to explain why such 
standards should be used in this regulation.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, Feb. 16, 1994) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    EPA has determined that this proposed rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority or low-income populations. While EPA was unable to 
perform a detailed environmental justice analysis because it lacks data 
on the location of POTWs to which dental discharges currently occur, 
the proposal would increase the level of environmental protection for 
all affected populations without having any disproportionately high and 
adverse human health or environmental effects on any population, 
including any minority or low-income population. The proposed rule will 
reduce the amount of mercury from dental amalgam entering POTW's and 
eventually the nation's waters, to benefit all of society, including 
minority communities.
    EPA welcomes comments on this aspect of the proposed rulemaking 
and, specifically, invites the public to identify potential 
environmental justice considerations associated with this proposed 
regulation.

List of Subjects in 40 CFR Parts 403 and 441

    Environmental protection, Dental, Dental office, Dentist, Mercury, 
Pretreatment, Waste treatment and disposal, Water pollution control.

    Dated: September 23, 2014.
Gina McCarthy,
Administrator.

    Therefore, it is proposed that 40 CFR parts 403 and 441 be amended 
as follows:

PART 403--GENERAL PRETREATMENT REGULATIONS FOR EXISTING AND NEW 
SOURCES OF POLLUTION

0
1. The authority citation for part 403 continues to read as follows:

    Authority:  33 U.S.C. 1251, 1311, 1314, 1316, 1317, 1318, 1342, 
and 1361.

0
2. In Sec.  403.3, add paragraph (v)(4) to read as follows:


Sec.  403.3  Definitions.

* * * * *
    (v) * * *
    (4) An industrial user subject to categorical Pretreatment 
Standards under 40 CFR part 441 is designated a Dental Industrial User 
(DIU) rather than a Significant Industrial User (SIU) if the Industrial 
User (IU) has complied with 40 CFR part 403, the applicable 
pretreatment standards for existing sources (PSES) or pretreatment 
standards for new sources (PSNS) and the monitoring and reporting 
requirements of 40 CFR 441.60. If a DIU has not complied with these 
requirements and standards, such IU will be considered a SIU until the 
Control Authority evaluates the IU as specified in Sec.  
403.8(f)(2)(v)(D).
* * * * *
0
3. In Sec.  403.8, add paragraph (f)(2)(v)(D) to read as follows:


Sec.  403.8  Pretreatment Program Requirements: Development and 
Implementation by POTW.

* * * * *
    (f) * * *
    (2) * * *
    (v) * * *
    (D) Where the publicly owned treatment works (POTW) finds that an 
Industrial User (IU) meets the criteria for classification as a Dental 
Industrial User (DIU), the POTW must evaluate, at least once per year, 
whether the IU meets the criteria in Sec.  403.3(v)(4). In the event 
that the POTW determines that a DIU does not meet the criteria in Sec.  
403.3(v)(4), the POTW must immediately begin enforcement in accordance 
with its enforcement response plan. If the dental discharger has not 
returned to compliance within 90 days of the initial noncompliance, the 
POTW may no longer treat the dental discharger as a DIU and must treat 
the dental discharger as a SIU. Upon verification by the POTW through 
an inspection and a finding that the dental discharger has complied 
with all of the applicable requirements in Sec.  403.3(v)(4), the 
dental discharger may be considered a DIU.
* * * * *
0
4. Add part 441 to read as follows:

PART 441--DENTAL OFFICE (MERCURY AMALGAM) POINT SOURCE CATEGORY

Sec.
441.10 Applicability.
441.20 General definitions.
441.30 General pretreatment requirements.
441.40 Pretreatment standards for existing sources (PSES).
441.50 Pretreatment standards for new sources (PSNS).
441.60 Discharge monitoring, reporting, and recordkeeping 
requirements.

    Authority:  33 U.S.C. 1251, 1311, 1314, 1316, 1317, 1318, 1342, 
and 1361. 42 U.S.C. 13101 et seq.


Sec.  441.10  Applicability.

    (a) Except as provided in paragraphs (b) and (c) of this section, 
the provisions of this part are applicable to discharges of wastewater 
to publicly owned treatment works from facilities where the practice of 
dentistry is performed (``dental dischargers''), including but not 
limited to institutions, permanent or temporary offices, clinics, 
mobile units, home offices, and facilities, and including dental 
facilities owned and operated by Federal, state, or local governments.
    (b) The provisions of this part do not apply to process wastewater 
discharges from dental dischargers which exclusively practice one or 
more of the following dental specialties: oral pathology, oral and 
maxillofacial radiology, oral and maxillofacial surgery, orthodontics, 
periodontics, or prosthodontics;
    (c) Dental Dischargers will be exempt from any further requirements 
of this rule so long as they:
    (1) Do not place or remove amalgam except in limited emergency 
circumstances
    (2) Certify to the Control Authority that that they do not and will 
not use or remove amalgam, including the following information:
    (i) The facility name, address, contact information.
    (ii) The dental license number of all practicing dentists at the 
location.

[[Page 63285]]

    (3) Notify the Control Authority of any changes to information 
required under paragraphs (c)(2)(i) and (ii) of this section.
    (4) Information provided to comply with paragraphs (c)(2)(i) and 
(ii) of this section must be signed by the responsible corporate 
officer as defined in Sec.  403.12(l).


Sec.  441.20  General definitions.

    For purposes of this part:
    Amalgam process wastewater means any wastewater generated and 
discharged by a dental discharger through the practice of dentistry 
that may contain dental amalgam.
    Amalgam separator means a collection device designed to capture and 
remove dental amalgam from the amalgam process wastewater of a dental 
facility.
    Control Authority is defined in 40 CFR 403.3(f).
    Dental amalgam means an alloy of elemental mercury and other metals 
that is used in the practice of dentistry.
    Dental Discharger means a source of wastewater to a publicly owned 
treatment works from a facility where the practice of dentistry is 
performed as described in 40 CFR 441.10.
    Dental Industrial User (DIU) means a dental discharger as described 
in Sec.  441.10(a) that meets the requirements of 40 CFR 441.60.


Sec.  441.30  General pretreatment requirements.

    (a) Any source subject to this part that introduces process 
wastewater pollutants into a publicly owned treatment works (POTW) must 
comply with 40 CFR part 403.
    (b) [Reserved]


Sec.  441.40  Pretreatment standards for existing sources (PSES).

    Except as provided in 40 CFR 403.7 (removal credits) and 403.13 
(fundamentally different factors) and no later than [DATE 3 YEARS AFTER 
EFFECTIVE DATE OF THE FINAL RULE IN THE FEDERAL REGISTER], any existing 
source subject to this part must achieve the following pretreatment 
standards:
    (a) Removal of at least 99.0% of total mercury from amalgam process 
wastewater and
    (b) Incorporation of the following best management practices:
    (1) Scrap amalgam (contact and non-contact), including but not 
limited to dental amalgam from chair-side traps, screens, vacuum pump 
filters, dental tools, or collection devices may not be flushed down 
the drain.
    (2) Chair-side traps that may drain to a sewer must be cleaned with 
non-bleach, non-chlorine containing cleaners that have a pH of 6 to 8. 
Such cleaning must be conducted at least weekly.
    (3) Certification that the BMPs specified in paragraphs (b)(1) and 
(2) of this section are being followed is deemed to meet these 
requirements.
    (c) The requirements of paragraph (a) of this section may be met by 
installation and operation of at least one 2008 ISO 11143 certified 
amalgam separator that:
    (1) Is certified to meet a removal efficiency of no less than 
99.0%;
    (2) Receives all amalgam process wastewater;
    (3) Is sized to incorporate all wastewater that may pass through 
it;
    (4) Is inspected at least once per month to ensure proper operation 
and maintenance of the separator, including confirmation that amalgam 
process wastewater is flowing through the retaining cartridge, 
separator canister, or amalgam separating portion of the amalgam 
separator (preventing bypass);
    (5) In the event that the separator is found to not be functioning 
properly, is repaired or replaced according to manufacturer 
instructions; and
    (6) Is regularly maintained by replacing the amalgam retaining 
cartridge(s), separator canister(s), or separator unit(s) whenever the 
collection of retained solids reaches the manufacturer's stated design 
capacity or annually, whichever comes first.
    (d) Dental Dischargers that operate an amalgam separator certified 
under the 1999 or 2008 ISO 11143 standard installed at a dental 
facility prior to October 22, 2014, satisfy the requirements of 
paragraph (a) of this section until [DATE 10 YEARS AFTER EFFECTIVE DATE 
OF THE FINAL RULE IN THE FEDERAL REGISTER] if the existing amalgam 
separator:
    (1) Receives all amalgam process wastewater;
    (2) Is sized to incorporate all amalgam process wastewater that may 
pass through it;
    (3) Is inspected at least once per month to ensure proper operation 
and maintenance of the separator, including confirmation that 
wastewater is flowing through the retaining cartridge, separator 
canister, or amalgam separating portion of the amalgam separator 
(preventing bypass); and
    (4) Is regularly maintained by replacing the amalgam retaining 
cartridge(s), separator canister(s), or separator unit(s) whenever the 
collection of retained solids reaches the manufacturer's rated design 
capacity or annually, whichever comes first.


Sec.  441.50  Pretreatment standards for new sources (PSNS).

    Except as provided in 40 CFR 403.7 (removal credits) and 40 CFR 
403.13 (fundamentally different factors), any new source subject to 
this part must achieve PSNS as follows:
    (a) Removal of at least 99.0% of total mercury from amalgam process 
wastewater and
    (b) Incorporation of the following best management practices 
(BMPs):
    (1) Scrap amalgam (contact and non-contact), including but not 
limited to dental amalgam from chair-side traps, screens, vacuum pump 
filters, dental tools, or collection devices may not be flushed down 
the drain.
    (2) Chair-side traps that may drain to a sewer must be cleaned with 
non-bleach, non-chlorine containing cleaners that have a pH of 6 to 8. 
Such cleaning must be conducted at least weekly.
    (3) Certification that the BMPs specified in (1) and (2) of this 
subpart are being followed is deemed to meet these requirements.
    (c) The requirements of paragraph (a) of this section may be met by 
installation and operation of at least one 2008 ISO 11143 certified 
amalgam separator that:
    (1) Is certified to meet a removal efficiency of no less than 
99.0%;
    (2) Captures all amalgam process wastewater;
    (3) Is sized to incorporate all amalgam process wastewater that may 
pass through it;
    (4) Is inspected at least once per month to ensure proper operation 
and maintenance of the separator, including confirmation that amalgam 
process wastewater is flowing through the retaining cartridge, 
separator canister, or amalgam separating portion of the amalgam 
separator (preventing bypass);
    (5) In the event that the separator is found to not be functioning 
properly, is repaired or replaced according to manufacturer 
instructions; and
    (6) Is regularly maintained by replacing the amalgam retaining 
cartridge(s), separator canister(s), or separator unit(s) whenever the 
collection of retained solids reaches the manufacturer's stated design 
capacity or annually, whichever comes first.


Sec.  441.60  Discharge monitoring, reporting, and recordkeeping 
requirements.

    (a) Dental dischargers may comply with the following monitoring and 
reporting requirements in lieu of the otherwise applicable requirements 
in Sec.  403.12(b), (d), and (e).
    (1) Baseline report. For existing sources, a baseline report must 
be

[[Page 63286]]

submitted within 180 days of the effective date of this rule. For new 
sources, a baseline report must be submitted at least 90 days prior to 
commencement of discharge. It must include:
    (i) The facility name, address, and contact information as well as 
the dental license number of all practicing dentists at the location.
    (ii) A description of the operation at the dental discharger 
including:
    (A) The total number of chairs,
    (B) The total number of chairs at which dental amalgam may be 
present in the resulting wastewater;
    (C) For existing sources, a description of any existing amalgam 
separators currently operated to include, at a minimum, the make, 
model, and manufacturers recommended frequency of container change. If 
no separators are currently employed, indicate none. For new sources, a 
description of any planned amalgam separators to include, at a minimum, 
the make, model, and manufacturers recommended frequency of container 
change.
    (iii) For existing sources, statement of whether or not the 
facility currently employs the best management practices (BMPs) 
specified in Sec.  441.40(b).
    (2) 90-day compliance report. For existing sources, a compliance 
report must be submitted within [90 days after the final compliance 
date of this rule]. For new sources, a compliance report must be 
submitted within 90 days following commencement of the introduction of 
wastewater into the publicly owned treatment works (POTW). The report 
must include:
    (i) The facility name, address, and contact information as well as 
the dental license number of all practicing dentists at the location.
    (ii) A description of the operation at the dental office including:
    (A) The total number of chairs, and
    (B) The total number of chairs at which dental amalgam may be 
present in the resulting wastewater.
    (C) A description of any existing amalgam separators currently 
operated to include, at a minimum, the make, model, and manufacturers 
recommended frequency of container change.
    (iii) Certification that the design and operation of separators 
meet the requirements specified in Sec.  441.40 or Sec.  441.50, as 
applicable.
    (iv) Certification that the facility is employing BMPs specified in 
Sec.  441.40(b) or Sec.  441.50(b), as applicable.
    (3) Periodic monitoring report. A periodic report of ongoing 
compliance must be submitted annually. The reports must include:
    (i) The facility name, address, and contact information as well as 
the dental license number of all practicing dentists at the location;
    (ii) If no changes have occurred since submission of the most 
recent compliance submission (e.g. 90-day compliance report or periodic 
monitoring report);
    (iii) Certification that the design and operation of the separators 
meets the requirements specified in Sec.  441.40 or Sec.  441.50, as 
applicable and that the facility is employing the BMPs specified in 
Sec.  441.40(b) or Sec.  441.50(b), as applicable;
    (iv) If changes have occurred since submission of the most recent 
compliance submission (e.g. 90-day compliance report or periodic 
monitoring report), you must submit the updated information required 
for the 90-day compliance report as specified in Sec.  441.60(a)(2).
    (b) If the dental discharger complies with the applicable 
requirements in 40 CFR part 403 and the monitoring and reporting 
requirements described in paragraphs (a)(1) through (3) of this 
section, in addition to the applicable pretreatment standards for 
existing sources (PSES) or pretreatment standards for new sources 
(PSNS) in Sec.  441.40 or Sec.  441.50, the dental discharger may be 
considered a Dental Industrial User (DIU) by the Control Authority; 
otherwise the Control Authority must treat the dental discharger as a 
Significant Industrial User (SIU) as defined in 40 CFR 403.3(v). 
Reports submitted to comply with this section must be signed by the 
responsible corporate officer as defined in 40 CFR 403.12(l).
    (c) Dental dischargers must maintain on site and available for 
inspection (in either physical or electronic form) the following 
records for a period of three years from the date they are created:
    (1) The baseline report required in paragraph (a)(1) of this 
section;
    (2) The 90-day compliance report required in paragraph (a)(2) of 
this section;
    (3) The periodic monitoring report required paragraph (a)(3) of 
this section;
    (4) Documentation including the date of each visual inspection of 
the amalgam separator(s) as specified in Sec.  441.40(c)(4) or Sec.  
441.50(c)(4), including records of visual inspections of the amalgam 
separator to ensure that the device is not in bypass mode;
    (5) Documentation specifying the date of amalgam retaining 
cartridge replacement in accordance with Sec.  441.40(c)(5) or Sec.  
441.50(c)(5); and
    (6) Records indicating the date of amalgam retaining cartridges are 
sent off site for proper disposal and the shipping address of the 
facility to which amalgam retaining cartridges are sent.

[FR Doc. 2014-24347 Filed 10-21-14; 8:45 am]
BILLING CODE 6560-50-P


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