United States Office of Water EPA-821 -R-14-006
Environmental Protection Washington, DC 20460 October 2014
Agency
i&EPA Technical and Economic
Development Document for
the Proposed Effluent
Limitation Guidelines and
Standards for the Dental
Category
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&EPA
United States
Environmental Protection
Agency
Technical and Economic Development Document
for the Proposed Effluent Limitation Guidelines
and Standards for the Dental Category
(40 CFR 441)
EPA-821-R-14-006
October 2014
U.S. Environmental Protection Agency
Office of Water (43 03 T)
Engineering and Analysis Division
1200 Pennsylvania Avenue, NW
Washington, DC 20460
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Acknowledgements and Disclaimer
This document was prepared by the Environmental Protection Agency. Neither the United States
Government nor any of its employees, contractors, subcontractors, or their employees make any
warrant, expressed or implied, or assume any legal liability or responsibility for any third party's
use of or the results of such use of any information, apparatus, product, or process discussed in
this report, or represents that its use by such party would not infringe on privately owned rights.
Questions regarding this document should be directed to:
U.S. EPA Engineering and Analysis Division (4303T)
1200 Pennsylvania Avenue NW
Washington, DC 20460
(202) 566-1000
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Table of Contents
TABLE OF CONTENTS
Page
SECTION 1 BACKGROUND 1-1
1.1 Legal Authority 1-1
1.2 Regulatory Background 1-1
1.2.1 Clean Water Act 1-1
1.2.2 Pollution Prevention Act 1-4
1.2.3 The National Pretreatment Program, 40 CFR 403 1-4
1.3 Regulatory History of the Dental Category 1-5
1.3.1 Detailed Study of the Dental Category 1-5
1.3.2 2008 Memorandum of Understanding on Reducing Mercury
Discharges 1-6
1.3.3 ADA Best Management Practices and Support for a National
Rulemaking 1-6
1.3.4 State and Local Programs 1-6
1.4 References 1-6
SECTION 2 SUMMARY AND SCOPE 2-1
2.1 Summary of the Proposed Rule 2-2
2.2 Applicability of the Proposed Rule 2-3
2.3 Subcategorization 2-3
2.4 References 2-4
SECTION 3 DATA COLLECTION ACTIVITIES 3-1
3.1 Health Services Industry Detailed Study 3-1
3.2 Literature Review 3-1
3.3 Meetings with Stakeholders 3-2
3.3.1 Environmental Council of the States 3-2
3.3.2 Environmental Organizations 3-2
3.3.3 American Dental Association (ADA) 3-2
3.3.4 National Association of Clean Water Agencies (NACWA) 3-2
3.4 Amalgam Separator Manufacturers (Vendor Contacts) 3-2
3.5 Air Force Study 3-3
3.6 References 3-3
SECTION 4 PROFILE OF DENTAL INDUSTRY 4-1
4.1 Number of Dental Offices 4-1
4.2 Specialty Practices at Dental Offices 4-3
4.3 Discharge Information 4-4
4.4 References 4-5
SECTION 5 DENTAL AMALGAM WASTE, POLLUTANTS OF CONCERN, AND POTW PASS
THROUGH 5-1
5.1 Sources of Dental Amalgam in Wastewater from Dental Offices 5-1
5.2 Dental Office Configuration 5-1
5.3 Pollutants of Concern and Pass Through 5-3
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Table of Contents
5.3.1 POTW Pass Through Analysis 5-3
5.4 References 5-4
SECTION 6 CURRENT NATIONAL, STATE, AND LOCAL DENTAL MERCURY REDUCTION
PROGRAMS 6-1
6.1 National Dental Amalgam Requirements and Guidance 6-1
6.1.1 U.S. EPA Strategies to Reduce Mercury Discharges 6-1
6.1.2 Occupational Safety and Health Administration 6-2
6.1.3 Food and Drug Administration 6-3
6.1.4 American Dental Association 6-3
6.2 State Dental Amalgam Requirements 6-5
6.3 Local Dental Amalgam Requirements 6-11
6.4 Voluntary Programs 6-14
6.4.1 Voluntary Programs with High Participation Rates 6-14
6.4.2 Voluntary Programs with Low Participation Rates 6-18
6.4.3 Summary of Participation Rates in Voluntary Programs 6-20
6.5 References 6-21
SECTION 7 TREATMENT TECHNOLOGIES AND BEST MANAGEMENT PRACTICES (BMPs) 7-1
7.1 Amalgam Separators 7-1
7.1.1 Treatment Process, Design, and Operation 7-1
7.1.2 Standards for Amalgam Separators 7-3
7.1.3 Treatment Efficiencies for Amalgam Separators 7-4
7.2 Polishing 7-7
7.3 Best Management Practices 7-7
7.4 References 7-8
SECTION 8 REGULATORY OPTIONS 8-1
8.1 Pretreatment Standards for Existing Sources (PSES) 8-1
8.1.1 Requirements 8-2
8.2 Pretreatment Standards for New Sources (PSNS) 8-3
8.3 References 8-4
SECTION 9 COSTS OF TECHNOLOGIES 9-1
9.1 Methodology for Developing Model Dental Office Costs 9-1
9.1.1 Model Compliance Costs for Dental Offices Without Amalgam
Separators 9-2
9.1.2 Model Compliance Costs for Dental Offices Currently Using
Amalgam Separators 9-7
9.2 Reporting Requirements and BMP Costs 9-7
9.3 Methodology for Developing Costs for Institutional Facilities 9-8
9.4 References 9-8
SECTION 10 ECONOMIC IMPACTS FOR THE DENTAL INDUSTRY 10-1
10.1 Overview of Dental Offices Potentially Subj ect to Proposed Regulation 10-1
10.1.1 Number of Dental Offices Potentially Subj ect to the Proposed
Regulation 10-1
10.1.2 Adjustments to Account for Baseline Status 10-3
10.2 Summary of the Proposed Regulation And Compliance Costs 10-6
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Table of Contents
10.2.1 Summary of Compliance Costs 10-6
10.2.2 Linking Compliance Costs By Number of Chairs to Dental Offices
by Revenue Range 10-10
10.3 Estimated Cost of Compliance to Dental Offices 10-14
10.3.1 Economic Impact of Compliance Costs 10-14
10.4 Social Cost of the Proposed Dental Amalgam Rule 10-25
10.4.1 Cost of Compliance on Social Cost Basis 10-26
10.4.2 Administrative Costs 10-26
10.4.3 Total Social Cost 10-27
10.5 Regulatory Flexibility Act Assessment 10-27
10.6 References 10-29
SECTION 11 POLLUTANT REDUCTION ESTIMATES 11-1
11.1 National Estimate of Annual Pollutant Loadings From Dental Offices 11-1
11.1.1 National Estimate of Annual Mercury in Dental Office Wastewater.... 11 -1
11.1.2 National Estimate of Annual Baseline Mercury Discharges from
Dental Offices to POTWs 11-3
11.1.3 National Estimate of Annual Non-Mercury Amalgam Metals in
Dental Offices Wastewater 11-4
11.1.4 National Estimate of Annual Baseline Discharges of Non-Mercury
Amalgam Metals from Dental Offices to POTWs 11-4
11.1.5 Total Annual Baseline Discharges to POTWs 11-5
11.2 National Estimate of Annual Pollutant Reductions to POTWs Associated
with the Proposed Dental Amalgam Rule 11-5
11.3 National Estimate of Annual Pollutant Reductions to Surface Waters
Associated with the Proposed Dental Amalgam Rule 11-5
11.4 References 11-6
SECTION 12 COST-EFFECTIVENESS ANALYSIS 12-1
12.1 Total Incremental Annualized Compliance Costs 12-1
12.2 Toxic Weighting Factors 12-1
12.3 Calculation of Annual Total Incremental Pound-Equivalents Removed to
Surface Waters 12-2
12.4 Cost-Effectiveness Results 12-2
12.5 References 12-3
SECTION 13 ENVIRONMENTAL IMPACTS OF DENTAL MERCURY DISCHARGES 13-1
13.1 Mercury in Dental Wastewater 13-1
13.2 Dental Mercury Fate and Transport 13-2
13.3 Environmental Assessment 13-2
13.3.1 Mercury in Surface Water Discharges 13-2
13.3.2 Mercury inBiosolids 13-3
13.3.3 Environmental Benefits of the Proposed Dental Amalgam Rule 13-3
13.4 References 13-4
SECTION! 4 NON-WATER-QUALITY IMPACTS 14-1
14.1 Energy Requirements 14-1
14.2 Solid Waste Generation 14-1
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Table of Contents
14.3 Air Emissions 14-2
14.4 References 14-2
SECTION 15 IMPLEMENTATION 15-1
15.1 Implementation Deadline for Existing Sources 15-1
15.2 Implementation Deadline for New Sources 15-1
15.3 Reporting requirements 15-1
SECTION 16 UPDATES TO GENERAL PRETREATMENT STANDARDS (40 CFR 403) 16-1
16.1 Proposed Changes to the General Pretreatment Standards 16-1
16.2 Responsibilities of the Control Authorities 16-2
16.2.1 Noncompliance 16-2
16.2.2 Classification of Dental Offices as Non-Significant Categorical
Industrial Users (NSCIU) 16-2
SECTION 17 GLOSSARY AND LIST OF ACRONYMS 17-1
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List of Tables
LIST OF TABLES
Page
Table 4-1. Number of Dental Offices by State (2007) 4-2
Table 4-2. Growth in Number of Dental Offices (1997 to 2007) 4-3
Table 4-3. Dental Offices with NPDES Permits in ICIS-NPDES 4-5
Table 4-4. Dental Offices with Discharge Data in ICIS-NPDES 4-5
Table 6-1. ADA BMPs for Dental Amalgam 6-3
Table 6-2. Summary of Elements of State Requirements 6-6
Table 6-3. Mandatory BMPs by State and Comparison to ADA BMPs a'b 6-8
Table 6-4. Voluntary BMPs by State and Comparison to ADA BMPs 6-10
Table 6-5. Summary of Elements of Local Requirements 6-11
Table 6-6. Best Management Practices by Municipality 6-12
Table 6-7. Summary of Voluntary Programs for Reducing Dental Amalgam Releases to
Wastewater 6-16
Table 7-1. Efficiency and Technology of 39 Amalgam Separators 7-5
Table 9-1. Cost of Purchasing, Operating, and Maintaining Amalgam Separators ($2010) 9-3
Table 9-2. Summary of One Time Costs ($2010) to Model Dental Offices Without
Amalgam Separators 9-6
Table 9-3. Summary of Annual Costs ($2010) to Model Dental Offices Without an
Amalgam Separator 9-7
Table 9-4. Percentage of Recurring Costs Incurred by Dental Offices Currently Using
Amalgam Separators 9-7
Table 9-5. Summary of Annual Model Facility Costs ($2010) to Dental Offices Currently
Using Amalgam Separators 9-7
Table 10-1. Dental Office Establishments by Revenue Range (NAICS 621210, Offices
of Dentists) 10-3
Table 10-2. Adjusting Office Counts to Account for Baseline Amalgam Use and
Technology in Place 10-5
Table 10-3. Dental Office Compliance Costs by Cost Category and Number of Chairs
(2010 dollars) 10-7
Table 10-4. Summary of Annualized Compliance Costs for a Dental Office or Large
Facility, Accounting for Initial Installation and Reinstallation of Amalgam
Separators, and Operational and Certification Costs 10-9
Table 10-5. Distribution of the Number of Chairs in Dental Offices 10-10
Table 10-6. Number of Chairs in Dental Offices by Revenue Range 10-12
Table 10-7. Annualized Costs to Complying Dental Offices by Number of Chairs 10-14
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List of Tables
Table 10-8. Revenue Range/Number-of-Chairs Combinations for Cost Impact Analysis 10-15
Table 10-9. Cost-to-Revenue Impact Summary 10-18
Table 10-10. Cost-to-Revenue Impact Summary by Number of Chairs 10-19
Table 10-11. Comparing Total Initial Outlay to Baseline Assets 10-20
Table 10-12. Composition of Dental Equipment for Six-Chair Office by Equipment Life ... 10-22
Table 10-13. Initial and Annual Replacement Outlay for Startup Dental Office by
Number of Chairs 10-23
Table 10-14. Comparing Total Initial Compliance Outlay to Steady State Annual
Replacement Outlay by Number of Chairs (Section 10.3.1.3) 10-24
Table 10-15. Comparing Total Initial Compliance Outlay to Initial Outlay by Number of
Chairs (Section 10.3.1.4) 10-24
Table 10-16. Compliance Costs on a Social Cost Basis for Proposed Dental Amalgam
Rule 10-26
Table 10-17. Summary of Social Cost for Proposed Dental Amalgam Rule 10-27
Table 10-18. Cost-to-Revenue Impact Analysis for Small Entities 10-28
Table 11-1. Mercury Waste Generation from the Restoration of Dental Amalgam 11-2
Table 11-2. Mercury Waste Generation from the Removal of Dental Amalgam 11-2
Table 11-3. Annual Untreated Mercury Generation from the Restoration and
Removal of Dental Amalgam 11-3
Table 11-4. Dental Office Use and Mercury Removal Efficiency by Treatment
Technology 11-4
Table 11-5. Calculation of Annual Untreated Non-Mercury Metal Generation from the
Restoration and Removal of Dental Amalgam 11-4
Table 12-1. Annualized Compliance Costs (Million $) 12-1
Table 12-2. Toxic Weighting Factors for Pollutants in Dental Amalgam 12-2
Table 12-3. Total Incremental Pound-Equivalents Removed from Surface Water
Discharges21 12-2
Table 12-4. PSES Cost-Effectiveness Analysis 12-3
Table 13-1. Mean Concentrations of Mercury Species in Dental Wastewater 13-1
Table 15-1. Compliance Time for Dental Offices Potentially Subject to the Proposed
Rule 15-1
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List of Figures
LIST OF FIGURES
Page
Figure 5-1. Typical Amalgam Separator Plumbing Configuration in a Dental Office 5-2
Vlll
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Section 1 - Background
SECTION 1
BACKGROUND
This section provides background information on the development of effluent limitation
guidelines and standards proposed for the Dental Category. Sections 1.1 and 1.2 present the legal
authority and discuss the regulatory background for the proposed rule, respectively. Section 1.3
provides a history of activities related to Dental Category rulemaking.
1.1 LEGAL AUTHORITY
The U.S. Environmental Protection Agency (EPA) is proposing effluent limitation
guidelines and standards (ELGs) for the Dental Category (40 CFR 441) under the authority of
sections 101, 301, 304, 306, 307, 308, and 501 of the Clean Water Act (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. § 13101etseq.
1.2 REGULATORY BACKGROUND
1.2.1 Clean Water Act
Congress passed the Federal Water Pollution Control Act Amendments of 1972, also
known as the Clean Water Act (CWA), to "restore and maintain the chemical, physical, and
biological integrity of the Nation's waters." (33 U.S.C. 125 l(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 limitation 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 publicly owned treatment works (POTWs). See section 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.
1-1
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Section 1 - Background
Technology-based effluent limitations in NPDES permits are derived from effluent limitation
guidelines (CWA sec. 301 and 304) and new source performance standards (sec. 306)
promulgated by EPA, or are based on best professional judgment in cases where EPA has not
promulgated an applicable effluent guideline or new source performance standard. Additional
limitations based on water quality standards (sec. 301(b)(l)(C) and 303) may also be included in
the permit in certain circumstances. The ELGs are established by regulation for various
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 limitation 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 sec. 307 of
the Act; and (3) non-conventional pollutants, which are neither conventional nor toxic (e.g.,
ammonia-N, formaldehyde, and phosphorus).
There are standards applicable to direct dischargers (dischargers to surface waters), and
standards applicable to indirect dischargers (discharges to POTWs). The standards relevant to
this rulemaking are summarized below.
1. Best Available Technology Economically Achievable (BAT)
BAT effluent limitation guidelines apply to direct dischargers of toxic and
nonconventional pollutants. In general, BAT effluent limitation 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)
New Source Performance Standards 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. 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,
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Section 1 - Background
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
(PSES) 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 limitation guidelines.
The General Pretreatment Regulations, which set forth the framework for the
implementation of categorical pretreatment standards, are found at 40 CFR 403.
4. Pretreatment Standards for New Sources (PSNS)
Like PSES, Pretreatment Standards for New Sources (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. Best Management Practices (BMPs)
Section 304(e) of the CWA authorizes the Administrator to publish regulations, in
addition to ELGs 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), holding that EPA's use of non-numerical effluent limitations in the form
of Best Management Practices are effluent limitations under the CWA; and Natural
Res. Def. Council Inc. v. EPA. 673 F.2d 400, 403 (D.C. Cir. 1982) which states
"section 502(11) [of the CWA] defines 'effluent limitation' as 'any restriction' on the
amounts of pollutants discharged, not just a numerical restriction."
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Section 1 - Background
1.2.2 Pollution Prevention Act
The Pollution Prevention Act of 1990 (PPA) (42 U.S.C. 13101 et seq., Public Law 101-
508, November 5, 1990) "declares it to be the national policy of the United States that pollution
should be prevented or reduced whenever feasible; pollution that cannot be prevented should be
recycled in an environmentally safe manner, whenever feasible; pollution that cannot be
prevented or recycled should be treated in an environmentally safe manner whenever feasible;
and disposal or release into the environment should be employed only as a last resort..." (Sec.
6602; 42 U.S.C. 13101 (b)). In short, preventing pollution before it is created is preferable to
trying to manage, treat, or dispose of it after it is created. The PPA directs the Agency to, among
other things, "review regulations of the Agency prior and subsequent to their proposal to
determine their effect on source reduction" (Sec. 6604; 42 U.S.C. 13103(b)(2)). EPA reviewed
this effluent guideline for incorporation of pollution prevention measures.
According to the PPA, source reduction reduces the generation and release of hazardous
substances, pollutants, wastes, contaminants, or residuals at the source, usually within a process.
The term source reduction "include[s] equipment or technology modifications, process or
procedure modifications, reformulation or redesign of products, substitution of raw materials,
and improvements in housekeeping, maintenance, training or inventory control. The term 'source
reduction' does not include any practice which alters the physical, chemical, or biological
characteristics or the volume of a hazardous substance, pollutant, or contaminant through a
process or activity which itself is not integral to or necessary for the production of a product or
the providing of a service" (42 U.S.C. 13102(5)). In effect, source reduction means reducing the
amount of a pollutant that enters a waste stream or that is otherwise released into the
environment prior to out-of-process recycling, treatment, or disposal.
1.2.3 The National Pretreatment Program, 40 CFR 403
The General Pretreatment Regulations of 40 CFR 403 establish responsibilities among
federal, state, and 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 comprises legal
authorities, procedures, funding, local limits, enforcement response plan, and the list of
significant industrial users, all of 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 also commonly referred to as
Industrial Users or lUs. All lUs are subject to general pretreatment standards (40 CFR 403),
1-4
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Section 1 - Background
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.
1.3 REGULATORY HISTORY OF THE DENTAL CATEGORY
This section presents a brief history of activities related to Dental Category rulemaking.
Section 1.3.1 discusses EPA's Detailed Study of the Dental Category. Section 1.3.2 discusses the
2008 memorandum of understanding (MOU) to reduce mercury discharges. Section 1.3.3
describes the American Dental Association's Best Management Practices and support of a
national rulemaking. Section 1.3.4 describes existing state and local programs for dental
discharges.
1.3.1 Detailed Study of the Dental Category
EPA first identified the dental industry for study in its review of the health services
industry in the 2006 Effluent Guidelines Plan (71 FR 76644). EPA selected the industry based in
part on public comments about discharges of mercury from dental offices and dental laboratories.
EPA's study addressed the following questions:
• What are the current industry practices for disposing of dental mercury, to what
extent are each of these practices applied, and what factors affect the use of these
practices?
• What are the federal, state, or local requirements or guidance for disposal of dental
mercury?
• How are control authorities currently limiting dental mercury discharges?
• Do POTWs report pass through or interference problems related to dental mercury
discharges?
• What technologies are available (1) as alternatives to wastewater disposal and (2) to
control discharges? How effective are these technologies?
• What BMPs are used as alternatives to wastewater disposal and/or to control
discharges? How effective are these practices?
• What are the costs of the identified technologies and/or BMPs?
EPA documented its findings in the August 2008 technical report, Health Services
Industry Detailed Study: Dental Amalgam (EPA-821-R-08-014).
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Section 1 - Background
1.3.2 2008 Memorandum of Understanding on Reducing Mercury Discharges
In December 2008, EPA signed a Memorandum of Understanding (MOU) with the
American Dental Association (ADA) and the National Association of Clean Water Agencies
(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. EPA did
not evaluate the effectiveness of the MOU, rather EPA decided that National Pretreatment
Standards for dental facilities would accomplish the goals of the MOU in a more predictable
timeframe.
1.3.3 ADA Best Management Practices 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 (ADA, 2007).
In late 2010, ADA's Board of Directors adopted nine principles upon which ADA
supported National Pretreatment Standards for dental facilities (ADA, 2010).
1.3.4 State and Local Programs
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.1 Additionally, at least 19
localities similarly have mandatory dental reduction pretreatment programs. These mandatory
programs require the use of amalgam separators and Best Management Practices. Removal
efficiency requirements for separators in mandatory program jurisdictions vary from 95 percent
to 99 percent. See Sections 6.2 and 6.3 of this document for more details on these programs.
1.4 REFERENCES
ADA. 2007. Best Management Practices for Amalgam Waste. Updated July 2007. Document
Control Number (DCN) DAGO 165.
ADA. 2010. ADA Principles to be used to Develop Mandatory Separator Pretreatment Rule.
Washington, DC. October 29. DCN DA00137.
New Mexico has a similar program scheduled to go into effect in 2015.
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Section 2 - Summary and Scope
SECTION 2
SUMMARY AND SCOPE
Across the United States, many states and POTWs (also referred to as municipal
wastewater treatment plants) are working to reduce discharges of mercury to POTWs. Numerous
studies have been conducted to identify the sources of mercury entering POTWs. According to
the 2002 Mercury Source Control and Pollution Prevention Program Evaluation prepared for the
Association for Metropolitan Sewerage Agencies (AMSA), dental practices are the main source
of mercury discharges to POTWs (Larry Walker Associates, 2002). Amalgam dental fillings
contain mercury and other metals. Mercury discharges can result when dentists dispose of old
amalgam fillings from patients' cavities, and dispose of excess amalgam after placing a new
filling.2 A study funded by the American Dental Association (ADA) published in 2005
estimated that dental offices contributed more than 50 percent (6.5 tons of 12.3 tons) of mercury
entering POTWs (Vandeven and McGinnis, 2005).3
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 regarding which certain measures should be taken.
Specifically, the Convention lists nine measures for phasing down the use of mercury in dental
amalgam, including promoting best environmental practices in dental facilities to reduce releases
of mercury and mercury compounds to water and land. Nations that are parties to the Minamata
Convention will be required to implement at least two of the nine measures addressing dental
amalgam.
EPA estimates that 4.4 tons of mercury from waste dental amalgam are discharged into
POTWs (U.S. EPA, 201 la). The physical processes at POTWs remove approximately 90 percent
of the mercury in wastewater. This mercury transfers to the biosolids (or sewage sludge)
generated during primary and secondary treatment processes (U.S. EPA, 1982). Mercury from
amalgam can enter the environment through the incineration, landfilling, and land application of
sludge, or through surface water discharge from POTWs. Once deposited, certain
microorganisms can change mercury into methylmercury, a highly toxic form that builds up in
fish, shellfish, and animals that eat fish. Fish and shellfish are the main sources of
methylmercury exposure to humans.
The proposed regulations for the dental industry include pretreatment standards for the
control of mercury in wastewater. This section summarizes the proposed rule, its application, and
subcategorization.
2 Other filling types, such as composite fillings, do not contain mercury or other metals.
3 EPA performs a similar calculation to estimate current mercury discharges from dental facilities. See Section 11 of
this document.
2-1
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Section 2 - Summary and Scope
2.1 SUMMARY OF THE PROPOSED RULE
EPA is proposing technology-based pretreatment standards under the Clean Water Act
(CWA) for discharges of pollutants into POTWs from existing and new dental offices4 that
discharge dental amalgam. The proposed rule would require dental offices to control the
discharge of mercury and other metals in dental amalgam into POTWs based on the best
available technology or best available demonstrated control technology (amalgam separators)
and the use of best management practices (BMPs). The BMPs are (1) eliminating the flushing of
scrap amalgam down drains and (2) cleaning chair-side traps with non-bleach, non-chlorine
cleaners. EPA is also proposing to amend selected parts of the General Pretreatment Regulations
(40 CFR 403) to streamline oversight requirements for the Dental Category.
EPA expects that compliance with this proposed rule would reduce the transfer of metals
to POTWs by 8.8 tons per year, almost half of which (4.3 tons) is mercury (U.S. EPA, 201 la).
EPA estimates the annual cost of the proposed rule would be $44 to $49 million (U.S. EPA,
201 Ib). EPA developed the proposed rule based on proper operation and maintenance of
amalgam separators that remove at least 99.0 percent of total mercury from amalgam process
wastewater, along with the use of the two BMPs.
Affected dental offices could meet the standard by using, properly operating, and
maintaining a dental amalgam separator certified to achieve at least 99.0 percent reduction of
total mercury according to the 2008 ISO 11143 standard (ISO, 2008), performing certain BMPs,
and certifying to this effect. Affected dental offices could also meet the standard by certifying
that they do not install or remove amalgam. ADA recommends that its dentists use the
technology on which the rule is based (i.e., amalgam separators and BMPs) (ADA, 2007; ADA,
2010). Further, 12 states have implemented mandatory dental mercury discharge reduction
programs that require amalgam separators and BMPs. For dental offices that have not yet
installed amalgam separators, EPA estimates that this is a low-cost technology with an
approximate average annual cost of $700 per office (U.S. EPA, 201 Ib). Opportunistic removal
of concentrated sources of mercury through low-cost amalgam separators at dental offices is a
common sense solution to managing mercury at the point in the waste stream where it is most
concentrated, and from where the mercury would otherwise be released to air, land, and water.
EPA is also proposing to amend selected parts of the General Pretreatment Regulations
(40 CFR 403) in order to streamline permitting and oversight requirements specific to the dental
sector. When categorical pretreatment standards apply to an industry, certain oversight
requirements are created. As defined in 40 CFR 403, facilities that are subject to categorical
pretreatment standards are referred to as Categorical Industrial Users (CIUs). The number of
dental offices that would likely be subject to national pretreatment standards is approximately ten
times the current number of CIUs. The proposed changes to 40 CFR 403 reflect EPA's
recognition that the current regulatory framework needs to be adjusted for the effective
implementation and enforcement of these pretreatment requirements on the dental industry.
Therefore, EPA is proposing a new classification of CIU, specifically tailored to the proposed
rule: Dental Industrial User (DIU). EPA is proposing that DIUs not be subject to the oversight
4 This document uses the general term "offices" to refer to any dentistry practice or facility that places or removes
dental amalgam containing mercury.
2-2
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Section 2 - Summary and Scope
requirements for Significant Industrial Users (i.e., control mechanism issuance requirement,
annual inspection, and sampling requirements). Rather, EPA is proposing to allow Control
Authorities to focus their oversight efforts on dental offices that fail to meet the compliance
requirements of the DIU.
2.2 APPLICABILITY OF THE PROPOSED RULE
EPA has not identified dental offices discharging amalgam waste directly to waters of the
United States. Because EPA has very limited information on any direct discharge of dental
amalgam, EPA is not proposing effluent limitation guidelines and new source performance
standards for direct dischargers at this time.
The proposed pretreatment standards apply to wastewater discharges to POTWs from
offices where dentistry is performed, including institutions, permanent or temporary offices,
clinics, mobile units, home offices, and facilities, including dental facilities owned and operated
by federal, state, or local governments. EPA is not proposing to include wastewater discharges
from dental offices specializing exclusively in 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 Section 4.2, these specialty practices do not
place (restore) or remove dental amalgam, and thus EPA does not expect these offices to have
any discharges of dental amalgam.
2.3 SUBCATEGORIZATION
In developing effluent limitation guidelines and pretreatment standards, EPA may divide
an industry category into groupings called subcategories to 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. US 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 takes 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 the dental office, specialty practices, and unusual
configurations that may be found at very large practices such as dental clinics and universities.
EPA proposes that establishing formal subcategories is not appropriate for the Dental 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
2-3
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Section 2 - Summary and Scope
that already have regulatory programs for controlling discharges of dental amalgam have been
largely successful without subcategorization.
2.4 REFERENCES
ADA. 2007. Best Management Practices for Amalgam Waste. Updated July 2007. Document
Control Number (DCN) DAGO 165.
ADA. 2010. ADA Principles to be Used to Develop Mandatory Separator Pretreatment Rule.
Washington, DC. October 29. DCN DA00137.
ISO. 2008. International Organization for Standardization. ISO 11143:2008 Dentistry -
Amalgam Separators Standard. July. DCNDA00138.
Larry Walker Associates. 2002. Mercury Source Control and Pollution Prevention Program
Evaluation. Prepared for Association for Metropolitan Sewerage Agencies. AMSA.
March (Updated July). DCN DA00006.
U.S. EPA. 1982. Fate of Priority Pollutants in Publicly Owned Treatment Works. EPA-440-1-
82-303. September. DCNDA00244.
U.S. EPA. 201 la. EPA Analysis: Part 441 Option Cost Calculations. MS Excel™ file. Office of
Water. Washington, DC. DCNDA00146.
U.S. EPA. 201 Ib. Economic Analysis for the Dental Amalgam Rule. MS Excel™ file. Office of
Water. Washington, DC. DCNDA00145.
Vandeven, J., and S. McGinnis. 2005. An Assessment of Mercury in the Form of Amalgam in
Dental Wastewater in the United States. Water, Air and Soil Pollution. 164:349-366.
DCN D AGO 163.
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Section 3 - Data Collection Activities
SECTION 3
DATA COLLECTION ACTIVITIES
EPA collected data from a variety of sources for the proposed Dental Amalgam Rule,
including the Health Services Industry Detailed Study, stakeholder discussions, amalgam
separator manufacturer contacts, and the United States Air Force study on commonly used
amalgam separator systems. This section includes a description of each data source; Section 4
through Section 14 of this document includes summaries and analyses of the data collected by
EPA. EPA used data from these sources to develop a profile of the industry, describe dental
mercury sources and waste characteristics, describe the environmental impacts of mercury,
identify state and local programs to reduce mercury discharges from dental offices, characterize
the effectiveness and costs of amalgam separators and best management practices (BMPs), and
develop pollutant discharge loadings estimates with and without control technologies.
3.1 HEALTH SERVICES INDUSTRY DETAILED STUDY
EPA first identified the dental industry for study in its 2006 Effluent Guidelines Plan (71
FR 76644) as part of the health services industry. In 2008, EPA published its results from the
detailed study in the technical report, Health Services Industry Detailed Study: Dental Amalgam
(U.S. EPA, 2008). For that report, EPA compiled and summarized information on mercury
discharges from dental offices, BMPs, and amalgam separators. Regarding amalgam separators,
EPA examined their frequency of use, their effectiveness in reducing mercury discharges to
publicly owned treatment works (POTWs), and the capital and annual costs of their installation
and operation. EPA also conducted a POTW pass-through analysis on mercury for the industry.
The detailed study report also includes a preliminary industry profile that provides the number of
dental offices, the number of small businesses, discharge information, financial characteristics of
the industry, and a description of the national, state, and local mandatory and voluntary programs
to reduce mercury wastewater discharges from dental offices.
3.2 LITERATURE REVIEW
EPA reviewed literature and collected data on various aspects of the dental industry,
amalgam separators, and mercury discharges, including:
• Current, relevant technical publications that describe the sources and generation of
mercury wastes at dental offices and the discharge of mercury and other amalgam
filling metals (i.e., copper, silver, tin, and zinc) to POTWs.
• Current information on possible treatment solutions (i.e., amalgam separators) for
dental offices to reduce mercury in the wastewater and their effectiveness.
• Current implementation costs for technologies to reduce mercury and other metal
discharges at dental offices.
3-1
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Section 3 - Data Collection Activities
3.3 MEETINGS WITH STAKEHOLDERS
EPA participated in several meetings with stakeholders including the Environmental
Council of the States, environmental organizations, the American Dental Association (ADA),
and the National Association of Clean Water Agencies (NACWA). Sections 3.3.1 through 3.3.4
summarize information collected during these meetings.
3.3.1 Environmental Council of the States
EPA participated in several meetings with the Quicksilver Caucus (QSC) of the
Environmental Council of the States. From QSC, EPA collected information on implementing
mandatory amalgam separator programs at the state level, mandatory program language, and
compliance reporting and monitoring. QSC also provided EPA with information on efficiency
standards for amalgam separators (ECOS, 2010).
3.3.2 Environmental Organizations
EPA met with a coalition of environmental organizations, led by The Environmental Law
and Policy Center and the National Resources Defense Council. Meetings between EPA and the
coalition of environmental organizations focused on identifying the environmental impacts of
dental amalgam discharges. In spring 2011, the coalition submitted a letter listing its suggested
BMPs for the proposed Dental Amalgam Rule (Wu, 2011).
3.3.3 American Dental Association (ADA)
EPA met with ADA in 2010 and 2011. ADA submitted data to EPA on their recently
adopted principles for addressing mercury discharges from dental offices, the number of
specialty offices in the industry, the geographic distribution of dental offices, financial
characteristics of the industry, and operating characteristics of the industry (ADA, 2010).
3.3.4 National Association of Clean Water Agencies (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 wastes from dental offices, implementing pretreatment programs for dental offices, and
implementing pretreatment standards for industries with similar characteristics as the dental
industry. NACWA also provided EPA with information on the burden to permitting authorities
of implementing a dental amalgam pretreatment standard under the existing requirements in Part
403 (U.S. EPA, 2011).
3.4 AMALGAM SEPARATOR MANUFACTURERS (VENDOR CONTACTS)
EPA met with, or participated in calls with, representatives of multiple amalgam
separator manufacturers (ERG, 2010; ERG and Air Techniques, 2011; ERG and American
Dental Accessories, 2011; ERG and DRNA, 2011; ERG and Rebec Solutions, 2011; ERG and
SolmeteX, 2011). The purpose of the meetings was to gather information on the following
issues:
3-2
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Section 3 - Data Collection Activities
• How amalgam separators work, limitations of the technology, and system capacity;
• Treatment technology effectiveness;
• Installation, operation, and maintenance requirements and equipment lifetime;
• Capital costs and operating and maintenance costs;
• Manufacturers' distribution methods;
• Amalgam disposal; and
• Installation trends.
3.5 AIR FORCE STUDY
In anticipation of the proposed Dental Amalgam Rule, the United States Air Force Dental
Evaluation and Consultation Service compiled a synopsis of commonly used amalgam separator
systems (U.S. Air Force, 2011). The purpose of this synopsis was to introduce dental clinics to
available amalgam separation system options. The Dental Evaluation and Consultation Service
focused on amalgam separators that are marketed directly to dentists (not necessarily all systems
available). The study includes tables for dentists to select the system that best meets their needs,
as well as highlighting key points, questions, and items for dentists to consider before purchasing
an amalgam separator. The study recommends that clinics actively involve their office managers
and biomedical engineering technicians in the purchasing decision to ensure compatibility of the
amalgam separator with existing office features, proper installation, future maintenance
requirements, and proper disposal of the waste.
For each system, the synopsis describes whether the separator is ISO 11143 certified,
installation requirements, design capacity, maintenance requirements, recycling services
available from the manufacturer, size, price, and warranty details. EPA incorporated these data
into the technology cost analysis.
3.6 REFERENCES
ADA. 2010. ADA Principles to be Used to Develop Mandatory Separator Pretreatment Rule.
Washington, DC. October 29. Document Control Number (DCN) DA00137.
ECOS. 2010. Letter to EPA: Implementing a National Vision of Mercury. Washington, DC.
August 19. DCNDA00158.
ERG (Eastern Research Group). 2010. SolmeteX meeting minutes for 15 December 2010.
Chantilly, VA. DCNDA00081.
ERG and Air Techniques. 2011. Notes from telephone conversation between Kimberly Landick,
ERG, and Air Techniques. March 2, 2011. Subject: Amalgam Separator Questions. DCN
DA00060.
ERG and American Dental Accessories. 2011. Email correspondence between Kimberly
Landick, ERG, and American Dental Accessories. February 28, 2011. Subject: Request
for Amalgam Separator Information. DCN DA00061.
3-3
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Section 3 - Data Collection Activities
ERG and DRNA (Dental Recycling North America). 2011. Notes from telephone conversation
between Kimberly Landick, ERG, and Marc Sussman and Darwin Moreira, DRNA.
March 1, 2011. Subject: Amalgam Separator Questions. DCNDA00062.
ERG and Rebec Solutions. 2011. Notes from telephone conversation between Kimberly Landick,
ERG, and Rebec Solutions. March 2, 2011. Subject: Amalgam Separator Questions. DCN
DA00063.
ERG and SolmeteX. 2011. Notes from telephone conversation between Kimberly Landick, ERG,
and SolmeteX, March 2, 2011: Subject Amalgam Separator Questions. DCN DA00064.
U.S. Air Force. 2011. Synopsis of Dental Amalgam Separators (Project #10-017). Dental
Evaluation and Consultation Service. February. DCN DA00079.
U.S. EPA. 2008. Health Services Industry Detailed Study: Dental Amalgam. EPA-821-R-08-014.
Washington, DC. August. DCN DA00057.
U.S. EPA, 2011. Information Collection Request: NationalPretreatment Program. OMB
Control No. 2040-0009, EPA ICRNo. 0002.14 (Draft). Office of Wastewater
Management. March. DCNDA00144.
Wu, Mae. 2011. Comments from Multi-state Mercury Products Campaign, the Environmental
Law and Policy Center, and National Resources Defense Council. April 1. Washington,
DC. DCNDA00136.
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Section 4 - Profile of Dental Industry
SECTION 4
PROFILE OF DENTAL INDUSTRY
The industry category that would be affected by the proposed rule is Offices of Dentists
(NAICS5 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 Management Organization (HMO) medical centers. They can provide either
comprehensive preventive, cosmetic, or emergency care, or specialize in a single field of
dentistry. EPA used data from the U.S. Census, EPA's Toxic Release Inventory (TRI), and
discharge monitoring reports (DMR)6 to estimate the number of dental offices and to understand
how they discharge their wastewater.
TRI and the U.S. Census classify industries by NAICS codes, while DMR classifies
industries by Standard Industrial Classification (SIC) codes. There is a 100 percent correlation
between NAICS and SIC codes for the dental industry. Dental offices fall under NAICS 621210
(SIC Code 8021), with the definition (Census, 2007a):
"This industry comprises establishments of health practitioners having the degree of
D.M.D. (Doctor of dental medicine), D.D.S. (Doctor of dental surgery), or D.D.Sc.
(Doctor of dental science) primarily engaged in the independent practice of general or
specialized dentistry or dental surgery. These practitioners operate private or group
practices in their own offices (e.g., centers, clinics) or in the facilities of others, such as
hospitals or health management organization (HMO) medical centers. They can provide
either comprehensive preventive, cosmetic, or emergency care, or specialize in a single
field of dentistry."
4.1 NUMBER OF DENTAL OFFICES
EPA's main source of information for the number of dental offices is the 2007 Economic
Census, which reported that there were 127,057 U.S. dental offices. Table 4-1 provides a
comprehensive listing of the dental offices by state for NAICS 621210 (Dental Offices). The
number of dental offices has increased approximately one percent each year. Table 4-2 shows the
industry changes over time. The financial profile of the dental industry is included in Section 10
of this document.
In addition to dental offices, dentistry can 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 that in addition to the 127,057 dental offices identified
from the Economic Census, there are 130 dental institutional facilities for a total of 127,187
dental offices/facilities. EPA recognizes that additional dental practices also exist at installations
operated by the federal government, specifically the Department of Defense. While EPA intends
North American Industry Classification System.
6
The DMR data are from EPA's Integrated Compliance Information System-National Pollutant Discharge
Elimination System (ICIS-NPDES) database.
4-1
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Section 4 - Profile of Dental Industry
such facilities to be subject to the proposed rule, EPA does not have information on which to
base an estimate of the number of such facilities.
Table 4-1. Number of Dental Offices by State (2007)
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
District of Columbia
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
NAICS 621210: Dental Offices
1,451
318
2,529
956
19,973
2,474
1,766
237
323
7,116
3,231
689
717
5,768
2,328
1,073
1,033
1,586
1,523
479
2,563
3,107
4,400
2,037
870
2,153
424
790
1,033
585
4,627
620
9,101
2,885
259
4,406
1,376
4-2
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Section 4 - Profile of Dental Industry
Table 4-1. Number of Dental Offices by State (2007)
State
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Total U.S.
NAICS 621210: Dental Offices
1,871
5,285
409
1,421
277
2,170
7,959
1,491
272
2,948
3,281
566
2,078
223
127,057
Source: Census, 2007b.
Table 4-2. Growth in Number of Dental Offices (1997 to 2007)
NAICS Code
621210: Offices
of Dentists
SIC Code
8021: Offices and
Clinics of Dentists
Number of
Offices in
1997
114,178
Number of
Offices in
2002
118,305
Number of
Offices in 2005
122,918
Number of
Offices in 2007
127,057
Sources: Johnston, 2005; Census, 2007c and 2007d.
4.2 SPECIALTY PRACTICES AT DENTAL OFFICES
Dentistry includes the evaluation, diagnosis, prevention, and treatment of diseases,
disorders, and conditions of the oral cavity, maxillofacial area, and the adjacent and associated
structures. Services provided include nonsurgical and surgical or related procedures. Most dental
offices fall under the category of general dentistry. In addition to a general practice, dentists may
specialize in other areas. Dentists who typically place or remove dental amalgam are either
general dentists or specialize in pediatric dentistry. The nine areas of dentistry that EPA
specifically evaluated for inclusion within the pretreatment standards include the following
(ADA, 2011):
• General dentistry—practice provides primary and comprehensive preventive and
therapeutic oral health care for patients.
4-3
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Section 4 - Profile of Dental Industry
• Pediatric dentistry—practice provides general dentistry services (i.e., primary and
comprehensive preventive and therapeutic oral health care) for age-specific group
(i.e., infants and children through adolescence).
• Endodontics—practice encompasses the basic and clinical sciences including biology
of the normal teeth (pulp) and diseases/injuries of the teeth and associated condition
of the root.
• Oral and maxillofacial pathology—practice focuses on diseases affecting the oral and
maxillofacial regions.
• Oral and maxillofacial radiology—discipline concerned with the production and
interpretation of images and data produced for the diagnosis and management of
diseases, disorders, and conditions of the oral and maxillofacial region.
• Oral and maxillofacial surgery—specialty includes the diagnosis, surgical and
adjunctive treatment of diseases, injuries, and defects involving both the functional
and esthetic aspects of the hard and soft tissues of the oral and maxillofacial region.
• Orthodontics and dentofacial orthopedics—specialty includes the diagnosis,
prevention, interception, and correction of malocclusion (i.e., misalignment of teeth),
as well as neuromuscular and skeletal abnormalities of orofacial structures.
• Periodontics—practice focuses on diseases of the supporting and surrounding tissues
of the teeth or their substitutes.
• Prosthodontics—specialty service for patients with clinical conditions associated with
missing or deficient teeth and/or oral and maxillofacial tissues using biocompatible
substitutes.
Of the specialty practices listed above (i.e., all practices except general and pediatric
dentistry), EPA expects only endodontic offices to place or remove amalgam. EPA is not
proposing to include wastewater discharges from dental offices where the practice does not
typically place or remove dental amalgam.
EPA does not have information on the number of practices that fall within each of the
nine areas identified above. Rather, EPA used ADA's 2009 Survey of Dental Practice to identify
the number of dental practices that are general practices or specialty practices. Based on the
information provided by ADA, EPA estimates that nationally, 21 percent of the total number of
dental offices (127,187) are categorized as specialty practices (ADA, 2010). EPA estimates that
65 percent of all specialty practices would fall within one of the areas that EPA is proposing not
to subject to the proposed rulemaking (Vandeven and McGuiness, 2005). Therefore, EPA
estimates that approximately 110,000 dental offices would be subject to the proposed
rulemaking.
4.3 DISCHARGE INFORMATION
EPA currently lacks a central database on reported discharges from dental offices. Often,
EPA looks to information in TRI and DMR databases to gather information on industrial
dischargers. However, no dental office (NAICS Code 621210) reports to TRI as they are not
4-4
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Section 4 - Profile of Dental Industry
required to do so. Based on information contained in the 2009 DMR database, EPA identified
five dental offices that have National Pollutant Discharge Elimination System (NPDES) permits.
The dental offices were classified as minor dischargers. Of these, only one office reported
discharge information in ICIS-NPDES. Table 4-4 summarizes the discharges reported by this
office.
Table 4-3. Dental Offices with NPDES Permits in ICIS-NPDES
NAICS
621210: Dental Offices
NPDES ID
LAG531791
LAG531821
LAG532300
LAG532353
MS0056901
SIC Code
8021
8021
8021
8021
8021
Office Name
Dr. Pellegrini DOS
Medical/Dental Office Building
Johnny J. Bouzigard DOS
Bayou Dental Care
Southern Training & Education
Location
Madisonville, LA
Mandeville, LA
Cut Off, LA
Raceland, LA
Starkville, MS
Source: U.S. EPA, 2009.
Table 4-4. Dental Offices with Discharge Data in ICIS-NPDES
NAICS
621210:
Dental
Offices
NPDES ID
MS0056901
Discharge
(Outfall)
001
001
001
001
Pollutant
Biochemical
Oxygen
Demand
(BOD5)
Chlorine,
total residual
Coliform,
fecal general
Total
Suspended
Solids
Average
Concentration
(mg/L)
134
0
1720
37
Maximum
Concentration
(mg/L)
134
0
1720
37
Pollutant
Discharge
(LEY)
244.92
0
3143.74
67.63
Total
Wastewater
Flow
(MGD)
0.0006
0.0006
0.0006
0.0006
Source: U.S. EPA, 2009.
LEY - pounds per year
MGD - million gallons per day
mg/L - milligrams per liter
The lack of information in TRI and DMR about dental industry wastewater discharges is
consistent with EPA's 2007 and 2005 reviews of the dental industry. These reviews indicate that
nearly all dental offices are indirect dischargers (Johnston, 2005; U.S. EPA, 2008).
4.4 REFERENCES
ADA. 2010. 2009 Survey of Dental Practice: Income from the Private Practice of Dentistry.
Document Control Number (DCN) DA00141.
4-5
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Section 4 - Profile of Dental Industry
ADA. 2011. Definitions of Special Areas of Dental Practice, http ://www. ada. org/25 55. aspx#top
DCN DA00044.
Census. 2007a. U.S. Census Bureau. Bridge Between NAICS and SIC Health Care and Social
Assistance - Offices of Dentists. 2007 Economic Census. DCN DA00186.
Census. 2007b. Industry Quick Report: Offices of Dentists and Dental Laboratories. 2007
Economic Census. DCN DA00048.
Census. 2007c. Sector 62: Health Care and Social Assistance: Geographic Area Series: Summary
Statistics: 2007. 2007 Economic Census. Subject Series. EC0762A1. DCNDA00046.
Census. 2007d. Sector 31: Manufacturing: Industry Series: Detailed Statistics by Industry for the
United States: 2007. 2007 Economic Census. Subject Series. EC0731I1. DCNDA00047.
Johnston, C. 2005. U.S. EPA. Industry Sectors Being Evaluated Under Proposed "Health
Services Industry" Category. Memorandum to the Public Record for the 2006 Effluent
Guidelines Program Plan. 4 August. DCN DA00172.
U.S. EPA. 2008. Health Services Industry Detailed Study: Dental Amalgam. EPA-821-R-08-014.
Washington, DC. August. DCN DA00057.
U.S. EPA. 2009. Discharge Monitoring Report Loads Database. DMRLoads2009_v01. DCN
DA00058.
Vandeven, J., and S. McGinnis. 2005. An Assessment of Mercury in the Form of Amalgam in
Dental Wastewater in the United States. Water, Air and Soil Pollution; 164:349-366.
DCN D AGO 163.
4-6
-------
Section 5 - Dental Amalgam Waste, Pollutants of Concern, and POTW Pass Through
SECTION 5
DENTAL AMALGAM WASTE, POLLUTANTS OF CONCERN,
AND POTW PASS THROUGH
This section discusses the sources of amalgam waste from dental offices and describes a
typical office configuration. This section also focuses on the pollutants of concern for amalgam
waste and the pass through of these pollutants at publicly owned treatment works (POTWs).
5.1 SOURCES OF DENTAL AMALGAM IN WASTEWATER FROM DENTAL OFFICES
Amalgam used in dental offices is approximately 49 percent mercury, by weight, mixed
with a powder of silver, tin, copper, and zinc, and small amounts of indium or palladium. The
liquid mercury and metal powder mixture are often supplied in capsules, in which they are kept
separate until the dentist is ready to complete a restoration. When the dentist triturates (mixes)
the mercury and powder, the mercury dissolves the powdered metals and a series of intermetallic
compounds (e.g., Ag3Sn, Ag2Hg3, Sn8Hg) are formed (Vandewall, 2007).
Amalgam discharges generally occur in the course of two dental office activities. The
first activity is patient treatment, such as during the placement or removal of a filling. When
filling a cavity, dentists overfill the tooth and then carve the filling into proper shape (Columbia
University, 2005). The dentist then typically rinses the excess amalgam into a chair-side drain
with a cuspidor or suctions it from the patient's mouth with a vacuum system. Dentists also
remove old cavity restorations that are worn or damaged. Removed restorations are also rinsed
into the chair-side drain or suctioned out of the patient's mouth. The second activity where
amalgam discharges occur is 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 also can result in discharge of dental amalgam mercury.
Dental amalgam use is diminishing in the United States. Due to the increased concern
regarding mercury in the environment, several U.S. industries have significantly decreased their
use of mercury since the 1980s (Vandeven and McGinnis, 2005). Although dental practices have
also reduced their mercury amalgam use, as of 2005, amalgam was still widely used for
restorations (Vandeven and McGinnis, 2005; Stone, 2004). ADA predicts that use of amalgam
will continue to decrease due to factors such as the introduction of improved filling material,
decreasing tooth decay rates, and earlier detection of tooth decay (U.S. EPA, 2007).
5.2 DENTAL OFFICE CONFIGURATION
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. A cuspidor may or may not be part
of the plumbing configuration at a dental office. The chair-side traps and vacuum pump filters
remove approximately 78 percent of dental amalgam particles from the wastewater stream
(Vandeven and McGinnis, 2005). Offices with multiple chairs typically share the vacuum lines
between chairs. Accordingly, this limits the locations for installation of control and treatment
technologies. Dental offices may install controls 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
-------
Section 5 - Dental Amalgam Waste, Pollutants of Concern, and POTW Pass Through
air/water separator portion of the vacuum system. Figure 5-1 displays a typical plumbing
configuration in a dental office and includes an amalgam separator installed at a central location
upstream of the vacuum pump. In this configuration, wastewater in the vacuum line goes through
the amalgam separator, and the cuspidor drain is connected to the central vacuum line (Dube,
2010; McManus and Fan, 2003).
Cuspido
Chan-side trap Cuspidor
•
('liair-side trap
Dental
"7 > I Operatories"
Air Exhaust
Basement
or Utility
Closet
= Vacuum line
= Wastewater to
sewer
= Air Exhaust
Amalgam
Separator1*
Vacuum
Pump Filtei
Vacuum
Pumpc
Wastewater to
sewer
a (Flight Dental Systems, 2006)
b (Dental Equipment & Repair, 2008)
c (Dental Classifieds, 2011)
Sources: Dube, 2010; McManus and Fan, 2003.
Figure 5-1. Typical Amalgam Separator Plumbing Configuration in a Dental Office
Physical office and building configurations may pose additional installation
considerations, such as space limitations in the absence of a basement, 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.
5-2
-------
Section 5 - Dental Amalgam Waste, Pollutants of Concern, and POTW Pass Through
5.3 POLLUTANTS OF CONCERN AND PASS THROUGH
As described above, dental amalgam is usually composed of mercury, silver, tin, copper,
zinc and small amounts of indium, and palladium. Of the dental amalgam constituents, mercury
is of greatest concern to human health because it is a persistent, toxic chemical that can
bioaccumulate 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 separation technologies considered for controlling mercury from
amalgam solids will be similarly effective on the other solid metals composing amalgam.
Therefore, controls installed for the reduction of mercury discharges will similarly reduce the
discharge of other metals contained in amalgam.
5.3.1 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 III of the 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
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, EPA compares the
percentage of the pollutant removed by typical POTWs achieving secondary treatment with the
percentage of the pollutant removed by facilities meeting BAT7 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 BPTYBAT 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.
In the case of the proposed Dental Amalgam Rule, 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 (U.S. EPA, 1982). The 50 POTW
study presents data on the performance of 50 POTWs performing secondary treatment to remove
toxic pollutants. Results of this study demonstrated that POTWs remove 90 percent of total
mercury found in wastewater. EPA received data from targeted studies performed by NACWA
that indicate a POTW can remove 95 percent of total mercury (NACWA, 2007). However, these
7 Best Available Technology Economically Achievable.
8 Best Practicable Control Technology Currently Available.
5-3
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Section 5 - Dental Amalgam Waste, Pollutants of Concern, and POTW Pass Through
studies reflect the performance of best performing POTWs, as opposed to the 50 POTW Study,
which reflects nationwide POTWs. Consequently, for the proposed Dental Amalgam Rule, EPA
maintains a POTW removal rate of 90 percent for its nationwide pass-through analysis. In
comparison, indirect dischargers using the proposed technology will remove 99.0 percent or
more of total mercury prior to discharge. Therefore, EPA concludes mercury passes through, and
is proposing requirements to control its discharge.
For the other metal constituents9, POTWs remove the following percentages from
wastewater prior to discharge (U.S. EPA, 1982):
• 88 percent of total silver;
• 79 percent of total tin;
• 84 percent of total copper; and
• 79 percent of total zinc.
EPA concludes that these metals contained in dental amalgam, also pass through POTWs
as defined above.
5.4 REFERENCES
American Dental Accessories. 2010. Tech Tips #24: Amalgam Separators. The Right Amalgam
Separator for You. Minneapolis, MN. July 28.
http://www.amerdental.com/blog/general/tech-tips-24/. Document Control Number
(DCN)DA00159.
Columbia University. 2005. October 19, 2005. Class II Amalgam Restoration.
http://www.columbia.edu/itc/hs/dental/_operative/amalgam.html. DCN DA00200
Dental Classifieds. 201 1. New Tech West Dental Vacuum 2 user Pump with Recycler.
http://www.dentalclassifieds.com/listing.asp7Ln> 1 1 184&catID=46. DCNDA00053.
Dental Equipment & Repair. 2008. Amalgam Separator.
http ://dentalequipmentandrepair.com/id 1 22.html . DCN DA00054.
Dube, Al. 2010. SolmeteX. 12th Annual EPA New England Pretreatment Coordinators
Workshop, Amalgam Separator Inspection. October 13-14. DCNDA00056.
Flight Dental Systems. 2006. Operatory Systems > A3 Operatory System. DCNDA00065.
McManus, K.R., and P.L. Fan. 2003. Purchasing, Installing and Operating Dental Amalgam
Separators. Journal of the American Dental Association, 134:1054-1065. DCNDA00162.
NACWA (National Association of Clean Water Agencies). 2007. An Examination of Mercury
Levels at Clean Water Agencies 2003-2006. December 18. DCN DA00108.
9 EPA does not have information from the 50 POTW Study to estimate the POTW removals for indium and
palladium.
-------
Section 5 - Dental Amalgam Waste, Pollutants of Concern, and POTW Pass Through
Stone, M.E. 2004. The Effect of Amalgam Separators on Mercury Loading to Wastewater
Treatment Plants. Journal of the California Dental Association, 32(7):593-600. DCN
DA00018.
U.S. EPA. 1982. Fate of Priority Pollutants in Publicly Owned Treatment Works. EPA-440-1-
82-303. September. DCNDA00244.
U.S. EPA. 2007. State Mercury Medical/Dental Waste Programs. DCN DA00189.
Vandeven, J., and S. McGinnis. 2005. An Assessment of Mercury in the Form of Amalgam in
Dental Wastewater in the United States. Water, Air and Soil Pollution, 164:349-366.
DCN D AGO 163.
Vandewall, K.S. 2007. Dental Amalgam. DCNDA00199.
5-5
-------
Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
SECTION 6
CURRENT NATIONAL, STATE, AND LOCAL DENTAL
MERCURY REDUCTION PROGRAMS
National, state, and local programs have reduced discharges of dental mercury to publicly
owned treatment works (POTWs). National programs include the 2008 MOU between EPA, the
American Dental Association (ADA), and the National Association of Clean Water Agencies
(NACWA) (see Section 1.3.2) and best management practices (BMP) guidance from ADA.
Currently, 12 states have established mandatory state-wide programs to control mercury
discharges from dental offices. EPA also reviewed requirements for 19 local mandatory
programs spanning six states. This section includes the following subsections:
• Section 6.1 discusses national programs.
• Section 6.2 summarizes state programs.
• Section 6.3 summarizes local programs.
• Section 6.4 presents voluntary programs.
6.1 NATIONAL DENTAL AMALGAM REQUIREMENTS AND GUIDANCE
Federal agencies that have established regulations for dental amalgam include the
Occupational Safety and Health Administration (OSHA) and the Food and Drug Administration
(FDA). Both federal regulations, however, focus on aspects of dental amalgam related to
employee and consumer exposure and do not address wastewater discharges to POTWs. In the
past, EPA has issued guidance and other strategies to reduce releases of mercury to the
environment, including discharges of dental amalgam.
6.1.1 U.S. EPA Strategies to Reduce Mercury Discharges
Before developing the proposed pretreatment standards, EPA and its regional offices
worked closely with states and communities to develop strategies for reducing mercury
discharges, including discharges from dental offices. For example, EPA's Environmental
Technology Verification Program studied amalgam separators to determine effectiveness
(Grubbs, 2003). In addition, EPA regional offices participated in seminars and workshops with
local organizations and other federal agencies to evaluate risks, develop recommendations,
disseminate information, and communicate with the public regarding a wide range of mercury-
associated issues. For example, EPA Region 4 participated in the Project Team on Consumption
Advisories for Mercury in Gulf of Mexico Marine Fish. In addition, EPA Regions 5 and 8, as
well as EPA Headquarters, participated in the activities listed below to limit mercury discharge
from dental offices.
• Region 5. EPA and Environment Canada, working through the Great Lakes Bi-
national Toxics Strategy, created a Mercury Workgroup that promoted activities to
reduce mercury releases to the Great Lakes Basin. This Workgroup included
representative states, environmental organizations, and the Council of Great Lakes
Industries. The Workgroup's review of mercury releases in the Great Lakes area
-------
Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
focused on air emissions. As a result, the Workgroup did not collect trend data on
mercury releases to water. The Workgroup reviewed information on BMPs and
successful voluntary and regulatory approaches used in state and local programs,
including dental amalgam reduction programs in King County, WA; Toronto, ON;
Duluth, MN; and Cleveland, OH (Cain and Krauel, 2004). The Workgroup did not
quantify reductions in mercury use or reductions in wastewater discharges to POTWs.
• Region 8. EPA Region 8 developed a draft Mercury Control Strategy to help POTWs
control mercury pollution problems from commercial and smaller industrial users,
including dental offices. This draft Strategy included detailed information on the
development of BMPs, amalgam separators, and other removal and filtration devices,
as well as other background information regarding dental amalgam control
approaches (U.S. EPA, 2005).
EPA regulates the disposal of mercury-containing waste under the Resource
Conservation and Recovery Act (RCRA). A mercury-containing waste can be considered
hazardous in two ways: (1) as a listed waste; or (2) as a characteristic waste.10 A waste is defined
as a characteristic hazardous waste if it exhibits the toxicity characteristics for mercury, defined
as containing enough mercury to exceed the regulatory threshold of 0.2 mg/L (or 0.2 parts per
million [ppm]) when subjected to a specific leach test known as the TCLP (Toxicity
Characteristic Leaching Procedure; see 40 CFR 261.24). Persons who generate hazardous waste,
such as a waste that exhibits the hazardous characteristics for mercury, are subject to specific
requirements for the proper management and disposal of that waste. The federal RCRA
regulatory requirements differ depending upon how much hazardous waste a site generates per
month. Most dental practices generate less than 100 kilograms of non-acute hazardous waste per
month and less than 1 kilogram of acute hazardous waste per month.11 Such facilities are
therefore classified as "Conditionally Exempt Small Quantity Generators" (CESQGs). CESQGs
are not subject to most of the RCRA hazardous waste requirements, provided the waste is
managed properly. However, some states have additional requirements for CESQGs or do not
exempt CESQGs from all requirements (HERCenter, 2008).
6.1.2 Occupational Safety and Health Administration
OSHA's authority regarding dental amalgam is limited to employee exposure resulting
from handling or use of hazardous chemicals in the workplace. Dental amalgam is considered
non-hazardous to consumers who receive dental restorations because the amalgam is considered
benign once it is installed. However, workers handling amalgam have a greater potential for
exposure than consumers, because dental workers handle liquid mercury while they prepare
mercury amalgam restorations. For that reason, dental amalgam is classified as a hazardous
chemical under OSHA's Hazard Communication Standard. Workers who handle amalgam alloy
are entitled to protection under this standard, including the receipt of training and hazard
information. OSHA's focus on dental amalgam is unrelated to the disposal or discharge of spent
amalgam (OSHA, 1997).
10 There are also some source-specific hazardous wastes that are listed due to mercury; however, dental amalgam
wastes are not listed in the hazardous-waste regulations at 40 CFR 261 Subpart D.
11 Elemental mercury found in dental amalgam is a non-acute hazardous waste.
-------
Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
6.1.3 Food and Drug Administration
FDA regulates dental amalgam under the Federal Food, Drug, and Cosmetic Act
(FFDCA). The FFDCA classifies dental mercury as a Class I medical device and amalgam alloy
as a Class II medical device (see Title 21, Code of Federal Regulations, sections 872.3700 and
872.3050). Class I medical devices are subject to extensive safety regulations for use. Class II
medical devices are subject to additional special controls for use (Anderson, 2007). FDA and the
Centers for Disease Control focus on the health risks of amalgams to dentists, dental workers,
and patients, rather than on the disposal or discharge of spent amalgam (FDA, 2008).
6.1.4 American Dental Association
The American Dental Association (ADA) has developed several programs to reduce
dental mercury being discharged from dental offices. Programs include development of best
management practices, list of nine principles, and creation of an amalgam recovery program.
ADA Best Management Practices
The most widely known national voluntary program for reducing dental amalgam
releases to the environment is the "Best Management Practices for Amalgam Waste" developed
and approved by the ADA Board of Trustees. ADA first published this program in January 2003
and updated it in 2007 to include amalgam separators. The ADA-defmed BMPs are recognized
as the industry standard; all state and local voluntary programs are based on or derived from the
guidance provided in the ADA BMPs.
ADA provides guidance documents for its members and the general public for the
management and disposal of amalgam waste. These include information regarding proper
recycling of amalgam waste. ADA also provides advice for successful integration of BMPs into
dental offices, a directory of national dental amalgam waste recyclers, recommendations for safe
preparation and placement of amalgam restorations, safety information for managing mercury
spills, and advice on the purchase, installation, and operation of amalgam separators (ADA,
2007). Table 6-1 lists the ADA BMPs for dental amalgam.
Table 6-1. ADA BMPs for Dental Amalgam
Focus
Best Management Practice
General
Recycle amalgam waste as much as possible.
Do not flush amalgam waste down the drain or toilet.
Use line cleaners that minimize the dissolution of amalgam.
Do not use bleach or chlorine-containing cleaners to flush wastewater lines.
Because amalgam waste may be mixed with body fluids or other potentially infectious material, use
protective equipment such as utility gloves, masks, and protective eyewear when handling it.
Check with city, county, or local waste authorities for an amalgam waste recycler and for any special
requirements that may exist in the area for collecting, storing, and transporting amalgam waste.
Store amalgam waste in a covered plastic container labeled "Amalgam for Recycling" or as directed
by the recycler.
Store different types of amalgam (e.g., contact and non-contact) in separate containers for recycling.
6-3
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Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
Table 6-1. ADA BMPs for Dental Amalgam
Focus
Best Management Practice
Amalgam
capsules
Do not use bulk elemental mercury, also referred to as liquid or raw mercury.
Use pre-capsulated alloys and stock a variety of capsule sizes.
Recycle used disposable amalgam capsules.
Do not put disposable amalgam capsules in biohazard containers, infectious waste containers (red
bags), or regular garbage.
Non-
contact
amalgam
Salvage, store, and recycle non-contact amalgam.
Do not put non-contact amalgam waste in biohazard containers, infectious waste containers (red
bags), or regular garbage.
Place unused non-contact amalgam in a silver or gray storage container or a storage container with a
silver or gray label (keep containers sealed at all times).
Contact
amalgam
Salvage amalgam pieces from restorations after removal and recycle the amalgam waste.
Do not put contact amalgam waste in biohazard containers, infectious waste containers (red bags), or
regular garbage.
Recycle teeth that contain amalgam restorations after confirming with the recycler that they will
accept extracted teeth with amalgam restorations.
Do not dispose of extracted teeth that contain amalgam restorations in biohazard containers,
infectious waste containers (red bags), sharps containers, or regular garbage.
Do appropriately disinfect extracted teeth that contain amalgam restorations (e.g., 10 minutes in a
1:10 bleach-to-water solution).
Place unused contact amalgam in a silver or gray storage container or a storage container with silver
or gray label (keep containers sealed at all times).
Chair-side
traps
Use chair-side traps to retain amalgam and recycle the content.
Do not rinse chair-side traps containing amalgam over drains or sinks.
Disposable traps from dental units dedicated strictly to hygiene may be placed in with the regular
garbage.
Place disposable chair-side traps and the contents of reusable chair-side traps in a silver or gray
storage container or a storage container with a silver or gray label (keep containers sealed at all
times).
Amalgam
separators
Select an amalgam separator that complies with ISO 11143.
Follow the manufacturer's recommendations for maintenance and recycling procedures.
Other
amalgam
collection
devices
Recycle contents retained by the vacuum pump filter, amalgam separator, or other amalgam
collection device that may be used, if they contain amalgam.
Do not rinse vacuum pump filters containing amalgam, amalgam separator canisters, or other
amalgam collection devices that may be used over drains or sinks.
Change the filter according to the manufacturer's recommended schedule.
Place disposable vacuum pump filters and the contents of reusable vacuum pump filters in a silver or
gray storage container or a storage container with silver or gray label (keep containers sealed at all
times).
Bulk
elemental
mercury
Recycle bulk mercury.
Check with licensed recycler to determine if they accept it.
Do not pour bulk mercury waste in the garbage, into a red bag, or down the drain.
Check with state regulatory agency and municipality to find out if a collection program is available.
Source: ADA, 2007.
ADA Nine Principles
In 2010, ADA adopted a resolution that endorses a mandatory national pretreatment
standard for dental office wastewater if it is consistent with nine principles laid out in the
resolution. The nine principles are (ADA, 2010):
6-4
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Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
1. Any regulation should require covered dental offices to comply with BMPs patterned
on the those developed by ADA (see Table 6-1), including the installation of
International Organization for Standardization (ISO) compliant amalgam separators
or separators equally effective;
2. Any regulation should defer to existing state or local law or regulation requiring
separators so that the regulation would not require replacement of existing separators
compliant with existing applicable law;
3. Any regulation should exempt dental practices that do not place or remove amalgams,
or only de minimis amounts of amalgams;
4. Any regulation should include an effective date or phase-in period of sufficient length
to permit affected dentists a reasonable opportunity to comply;
5. Any regulation should provide for a reasonable opportunity for covered dentists to
repair or replace defective separators without being deemed in violation of the
regulation;
6. Any regulation should minimize the administrative burden on covered dental offices
by (e.g.) primarily relying upon self certification (subject to verification or random
inspection) and not requiring dental-office specific permits;
7. Any regulation should not include a local numerical limit set by the POTW;
8. Any regulation should not require wastewater monitoring at the dental office,
although monitoring of the separators to assure proper operation may be required; and
9. Any regulation should provide that compliance with it shall satisfy the requirements
of the Clean Water Act unless a more stringent local requirement is needed.
ADA Health First Amalgam Recovery Program
In 2013, ADA joined with HealthFirst to establish an amalgam recovery program. ADA
chose HealthFirst as its endorsed amalgam recovery service provider. Through the HealthFirst
Amalgam Recovery Program, ADA members are able to purchase an amalgam separator at a
reduced cost. HealthFirst also offers waste handling services, including arranging the shipment,
tracking, and documentation of waste to permitted waste handlers. In addition, other supplies
such as chair-side traps, filters, and ADA-approved amalgam buckets can also be purchased
through the program (ADA News, 2013; ADA Business Resources, 2014).
6.2 STATE DENTAL AMALGAM REQUIREMENTS
EPA identified 12 states as having mandatory program requirements for dental offices:
• Connecticut;
6-5
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Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
• Louisiana12;
• Maine;
• Massachusetts;
• Michigan;
• New Hampshire;
• New Jersey;
• New York;
• Oregon;
• Rhode Island;
• Vermont; and
• Washington.
In addition to the above states, New Mexico passed a bill in 2013 that creates the Dental
Amalgam Waste Reduction Act. The Act requires dental offices to remove dental amalgam from
waste streams by installing an amalgam separator by December 31, 2014 that complies with
international standards for removal efficiency (New Mexico Legislature, 2013).
States typically use the voluntary BMPs developed by ADA described above as the basis
for their dental mercury discharge regulations. As a result, the state requirements share several
common elements. Table 6-2 summarizes the elements of the various state regulations, including
the types of requirements included and the methods used to demonstrate compliance with the
regulations. Table 6-3 compares the state BMP requirements to the ADA BMPs.
Table 6-2. Summary of Elements of State Requirements
Element
Requirements
Amalgam separator
technology
specifications
Operation
specifications for
amalgam separators
Method for
demonstrating
compliance
Examples from State Requirements
Install amalgam separators (CT, LA, MA, ME, MI, NH, NJ, NY, OR, VT, WA, and only
offices inRI).
Follow state BMPs (CT, LA, MA, MI, NH, NJ, NY, OR, RI, VT, WA).
Do not use bulk mercury (LA, NJ, NY, OR).
new
Meet ISO Standard 11143 (CT, ME, MI, NH, NJ, NY, OR, RI, VT, WA).
Operate at 95% efficiency (MA, ME, MI, NY, VT).a
Operate at 98% efficiency (MA if new, ME if after 3/20/03).
Operate at 99% efficiency (NY if new, RI).
Must be operated at all times when dental procedures are performed (CT).
Must service every chair at office where amalgam waste is generated (MA).
New offices must have separators installed prior to opening (OR).
Submit separator certification to state environmental agency (CT, MA, ME, NJ).
Provide certification of compliance with BMPs (CT, MA, NH, NJ).
Maintain maintenance and servicing records and be able to provide upon request (CT, ME).
Provide written notice of method of disposing mercury removed by the separator (ME).
12 Louisiana state requirements under the Mercury Risk Reduction Act do not specifically require dental offices to
install amalgam separators; however, dental offices must follow BMPs recommended by the ADA. These BMPs
include the installation of amalgam separators.
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Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
Table 6-2. Summary of Elements of State Requirements
Element
Compliance tracking
Examples from State Requirements
Department of Environmental Protection (DEP) inspections (CT).
Web form for providing proof of compliance (RI).
Sources: CTDEP, 2006; Louisiana Legislature, 2006; MassDEP, 2007; Maine DEP, 2005; MIDEQ, 2008; NHDES,
2002; NYDEC, 2007; Oregon State Legislature, 2007; RIDEM, 2007; VTDEC, 2006; WADOE, 2005; Walsh, 2007.
a — In several states, if an office had an amalgam separator in operation prior to implementation of the state law,
then the state allowed the office to continue operating that separator at its current efficiency.
Bills for dental mercury controls have been proposed but not passed in the following
states:
• Alabama. In 2004, the Alabama State legislature began debate on two bills designed
to regulate the use of mercury in dental offices: HB 495, Mercury Amalgam Filling,
and HB 665, Bill to Require Dentists to Provide Information about Mercury or
Mercury Amalgam to Patients. It appears that both of these bills failed to clear the
House and were tabled in the House Health Committee (ALISON, 2007).
• Arkansas. The Mercury Poisoning Reduction Act of 2003 required the Arkansas
Department of Environmental Quality to develop a plan for reducing mercury
pollution from dental procedures and to implement a mandatory program for dental
offices by July 1, 2004 (Arkansas, 2003). However, EPA could not find information
to determine if this Act had been either enacted or enforced.
• California. In 2005, Assembly Bill 966, which would establish standards related to
amalgam in dental and related services, passed the state Senate by a vote of 51 to 28
but was vetoed by the governor's office (California Legislative Counsel, 2005).
Three states (Florida, Idaho, and Minnesota) and the District of Columbia provide
voluntary guidelines and BMPs to dental offices. Table 6-4 summarizes the BMPs for these
states and district and compares them to ADA's BMPs.
6-7
-------
Table 6-3. Mandatory BMPs by State and Comparison to ADA BMPs
a,b
Best Management Practice
Requirement/Guidance
ADA
G
CT
R
LA
R
MA
R
NH
R
NJ
R
NY
R
OR
R
RI
R
VT
R
WA
R
Initial Use
Use only pre-capsulated alloys and/or stock a variety of capsule sizes.
Do not use bulk mercury.
X
X
X
X
X
X
X
X
X
X
X
X
Recycling/Disposal
Manage amalgam waste through recycling as much as possible.
Recycle used disposable amalgam capsules.
Do not flush amalgam waste down the drain or toilet.
Salvage, store and recycle non-contact amalgam (scrap amalgam).
Salvage amalgam pieces from restorations after removal (contact amalgam) and recycle
amalgam waste.
Recycle teeth that contain amalgam restorations.
Do not put used disposable amalgam capsules in biohazard containers, infectious waste
containers (red bags) or regular garbage.
Do not put non-contact amalgam waste in biohazard containers, infectious waste containers
(red bags) or regular garbage.
Do not put contact amalgam waste in biohazard containers, infectious waste containers (red
bags) or regular garbage.
Do not dispose of extracted teeth that contain amalgam restorations in biohazard containers,
infectious waste containers (red bags), sharps containers or regular garbage.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Chair-Side Traps
Use chair-side traps to retain amalgam and recycle the content.
Do not rinse chair-side traps containing amalgam over drains or sinks.
Where appropriate, disposable amalgam traps are preferable to reusable traps.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Vacuum Pumps
Recycle contents retained by the vacuum pump filter or other amalgam collection device, if
they contain amalgam.
Do not rinse vacuum pump filters containing amalgam or other amalgam collection devices
over drains or sinks.
Use line cleaners that minimize the dissolution of amalgam.
Do not use bleach or chlorine-containing cleaners to flush wastewater lines.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
s
o
O
in
I
fa
a
r
o
I
o
OQ
-------
Table 6-3. Mandatory BMPs by State and Comparison to ADA BMPs
a,b
Best Management Practice
Requirement/Guidance
ADA
G
CT
R
LA
R
MA
R
NH
R
NJ
R
NY
R
OR
R
RI
R
VT
R
WA
R
Amalgam Separators
Install and use amalgam separators.
X
X
X
X
X
X
X
X
X
X
X
Other
If using mercury, maintain a mercury spill kit on site and train all staff on mercury spill
cleanup response procedures.
Do not disinfect teeth or any item that contains amalgam using heat.
X
X
X
X
X
X
X
X
X
s
o
O
Sources: ADA, 2007; CTDEP, 2006; Lamperti, 2007; Louisiana Legislature, 2006; MassDEP, 2007; NHDES, 2002; NJR, 2007; NYDEC, 2007; RIDEM, 2007;
VTDEC, 2006; and WADOE, 2005.
G — Guidance.
R — Requirement.
a — Michigan's Best Management Practices are not available online; Michigan's law requires that on or before December 31, 2013, dentists must install and use
an amalgam separator on each wastewater drain in the dentist's office that is used to discharge dental amalgam. The amalgam separator must have an efficiency
of 95 percent or greater as determined through testing in accordance with ISO 11143 standards (MIDEQ, 2008). Maine requires the installation and use of
amalgam separators but does not require that dental offices follow the state's Best Management Practices (Maine DEP, 2005).
b - Louisiana state requirements under the Mercury Risk Reduction Act do not specifically require dental offices to install amalgam separators; however, dental
offices must follow BMPs recommended by the ADA. These BMPs include the installation of amalgam separators (Louisiana Legislature, 2006).
in
I
fa
a
r
o
I
o
OQ
-------
Table 6-4. Voluntary BMPs by State and Comparison to ADA BMPs
Best Management Practice
ADA
DC
FL
ID
MN
Initial Use
Use only pre-capsulated alloys and/or stock a variety of capsule sizes.
Do not use bulk mercury.
X
X
X
X
X
X
X
X
Recycling/Disposal
Manage amalgam waste through recycling as much as possible.
Recycle used disposable amalgam capsules.
Do not flush amalgam waste down the drain or toilet.
Salvage, store, and recycle non-contact amalgam (scrap amalgam).
Salvage amalgam pieces from restorations after removal (contact amalgam) and recycle amalgam waste.
Recycle teeth that contain amalgam restorations.
Do not put used disposable amalgam capsules in biohazard containers, infectious waste containers (red bags), or regular garbage.
Do not put non-contact amalgam waste in biohazard containers, infectious waste containers (red bags), or regular garbage.
Do not put contact amalgam waste in biohazard containers, infectious waste containers (red bags), or regular garbage.
Do not dispose of extracted teeth that contain amalgam restorations in biohazard containers, infectious waste containers (red
bags), sharps containers, or regular garbage.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Chair-Side Traps
Use chair-side traps to retain amalgam and recycle the content.
Do not rinse chair-side traps containing amalgam over drains or sinks.
Where appropriate, disposable amalgam traps are preferable to reusable traps.
X
X
X
X
X
X
X
X
X
X
X
Vacuum Pumps
Recycle contents retained by the vacuum pump filter or other amalgam collection device, if they contain amalgam.
Do not rinse vacuum pump filters containing amalgam or other amalgam collection devices over drains or sinks.
Use line cleaners that minimize the dissolution of amalgam.
Do not use bleach or chlorine-containing cleaners to flush wastewater lines.
X
X
X
X
X
X
X
X
X
X
X
X
X
Amalgam Separators
Install and use amalgam separators.
X
X
X
Other
If using mercury, maintain a mercury spill kit on site and train all staff on mercury spill cleanup response procedures.
Do not disinfect teeth or any item that contains amalgam using heat.
X
X
X
s
o
O
in
I
fa
a
r
o
I
o
OQ
Sources: ADA, 2007; District of Columbia Water and Sewer Authority, 2012; FLDEP, 2001; ISO A, 2008; MDA, 2003.
-------
Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
6.3 LOCAL DENTAL AMALGAM REQUIREMENTS
EPA identified and reviewed nine mandatory program requirements for the following
localities:
• King County Wastewater Treatment Division (KCWTD), WA;
• East Bay Municipal Utility District (EBMUD), Oakland, CA;
• Palo Alto Regional Water Quality Control Plant (RWQCP), CA;
• Northeast Ohio Regional Sewer District (NEORSD), Cleveland, OH;
• Several Wisconsin sewerage districts: Madison, Milwaukee, Neenah-Menasha,
Oshkosh, GrandChute and Menasha West, Wausau, Fond du Lac and Green Bay-De
Pere, Waukesha, Watertown, Beloit, and La Crosse (Behm, 2008);
• Fort Collins and Boulder, CO;
• San Francisco, CA;
• Solon, OH; and
• Narragansett Bay, RI.
This list is not intended to be an exhaustive list of local programs. Table 6-5 summarizes
the elements of the local requirements to control discharges of dental mercury. Table 6-6
compares the lists of local BMPs to ADA's BMPs. Many elements included in the local
requirements are similar to those of the state requirements described in Section 6.2.
Table 6-5. Summary of Elements of Local Requirements
Element
Requirements
Exemptions
Technology specifications
Method for demonstrating
compliance
Compliance tracking
Examples from Local Requirements
Meet a mercury discharge limit of 0.2 ppm (King County) if a separator is not
installed.
Install amalgam separators (East Bay, Palo Alto, Wisconsin, Fort Collins, San
Francisco, Solon, Narragansett Bay).
Alternative to installing an amalgam separator:
- Office must pay a fee of $1,770 per year and be subject to inspections and
testing (East Bay).
- Office must obtain a discharge permit and monitor wastewater (San Francisco).
- Follow local BMPs (King County, Palo Alto, Northeast (NE) Ohio, Milwaukee,
Narragansett Bay).
Offices that remove amalgam no more than three days per year (King County).
Certain specialty fields (King County).
Offices that installed separators prior to regulation (Palo Alto).
Meet ISO Standard 1 1 143 (King County, Madison, East Bay).
Provide certification for separator (East Bay, Palo Alto, Madison, Milwaukee).
Provide certification of compliance with BMPs (East Bay, Palo Alto, NE Ohio,
Madison, Milwaukee).
Provide documentation of mercury waste hauling (East Bay, Palo Alto, NE Ohio).
Enforcement protocol including notice of violation, compliance schedule, and
penalties for noncompliance (King County).
Inspections performed by local POTW (East Bay, Palo Alto, Madison, Milwaukee).
Sources: EBMUD, 2005; KCWTD, 2007; MMSD, 2008; NEORSD, 2007; Palo Alto, 2007; Walsh, 2007.
6-11
-------
Table 6-6. Best Management Practices by Municipality
Best Management Practice
Requirement/Guidance
Municipality
ADA
G
East Bay,
Oakland,
CA
R
King
County,
WA
R
Milwaukee and
Madison, WIa
R
Narragansett
Bay,RI
R
NE Ohio,
Cleveland,
OH
R
Palo
Alto,
CA
R
Initial Use
Use only pre-capsulated alloys and/or stock a variety of capsule sizes.
Do not use bulk mercury.
X
X
X
X
X
X
X
X
X
X
Recycling/Disposal
Manage amalgam waste by recycling as much as possible.
Recycle used disposable amalgam capsules.
Do not flush amalgam waste down the drain or toilet.
Salvage, store, and recycle non-contact amalgam (scrap amalgam).
Salvage amalgam pieces from restorations after removal (contact
amalgam) and recycle amalgam waste.
Recycle extracted teeth that contain amalgam restorations.
Do not put used disposable amalgam capsules in biohazard
containers, infectious waste containers (red bags), or regular garbage.
Do not put non-contact amalgam waste in biohazard containers,
infectious waste containers (red bags), or regular garbage.
Do not put contact amalgam waste in biohazard containers, infectious
waste containers (red bags), or regular garbage.
Do not dispose of extracted teeth that contain amalgam restorations in
biohazard containers, infectious waste containers (red bags), sharps
containers, or regular garbage.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Chair-Side Traps
Use chair-side traps to retain amalgam and recycle the content.
Do not rinse chair-side traps containing amalgam over drains or sinks.
Where appropriate, disposable amalgam traps are preferable to
reusable traps.
X
X
X
X
X
X
X
X
X
X
X
X(G)
X
X
X(G)
X
X
ft
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o
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ON
O
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5?
fa
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o
o
E.
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I
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-------
Table 6-6. Best Management Practices by Municipality
Best Management Practice
Requirement/Guidance
Municipality
ADA
G
East Bay,
Oakland,
CA
R
King
County,
WA
R
Milwaukee and
Madison, WIa
R
Narragansett
Bay,RI
R
NE Ohio,
Cleveland,
OH
R
Palo
Alto,
CA
R
Vacuum Pumps
Recycle contents retained by the vacuum pump filter or other
amalgam collection device, if they contain amalgam.
Do not rinse vacuum pump filters containing amalgam or other
amalgam collection devices over drains or sinks.
Use line cleaners that minimize the dissolution of amalgam.
Do not use bleach or chlorine-containing cleaners to flush wastewater
lines.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X(G)
X(G)
X
X
X
X
Other
If using mercury, maintain a mercury spill kit on site and train all staff
on mercury spill cleanup response procedures.
Install and use amalgam separators.
X
X
X
X
X
X
X
X
X
X
X
ft
s
o
3
ON
O
Gfl
5?
fa
a
r
o
o
E.
a
ft
I
Sources: ADA, 2007; EBMUD, 2005; KCWTD, 2007; NEORSD, 2007; Palo Alto, 2007; Uva, 2007; MMSD and University of Wisconsin Extension. 2006.
a — The Milwaukee and Madison programs reference BMPs developed by the Wisconsin Dental Association (MMSD and University of Wisconsin Extension.
2006).
G — Guidance.
R — Requirement.
•I
o
-------
Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
6.4 VOLUNTARY PROGRAMS
Some states and localities have initiated voluntary rather than mandatory dental mercury
reduction programs. The following two subsections summarize voluntary local programs that
provided information to EPA on the participation rates for their programs. All of the programs
involve outreach to dentists to educate them on BMPs and use of amalgam separators. The level
of interaction between the program partners and local dentists varies greatly from program to
program. Follow-up activities to verify participation include surveys, visits to dental offices, and
contacting amalgam separator vendors and waste haulers for lists of customers. In some cases,
the available information did not give EPA enough details to determine how the programs
verified the participation rates. Table 6-7 summarizes the voluntary programs and presents the
participation rates for the programs. This table also contains some state voluntary program
participation rates for comparison purposes.
6.4.1 Voluntary Programs with High Participation Rates
This subsection describes case studies of three voluntary programs (Duluth, MN;
Wichita, KS; and Massachusetts) that achieved participation rates greater than 90 percent or
exceeded their goals for participation rates. It includes both local and state programs.
The Duluth, Minnesota program attributed its success to the following:
• High level of cooperation from local dental societies;
• One-on-one interaction with dentists; and
• Providing financial incentives to dentists.
Wichita and Massachusetts each took a two-phase approach to their programs. Phase 1
encouraged early installation of amalgam separators. Both states' programs included specific
goals and deadlines for participation. The second phase of the program implemented mandatory
requirements for installation of amalgam separators at dental offices. Both states reported
participation rates exceeding 50 percent for the voluntary phase. Based on the success of its
voluntary program, Kansas decided not to implement mandatory requirements. Massachusetts
decided to implement mandatory requirements under phase 2; however, the state rewarded the
dental offices that voluntarily installed amalgam separators during phase 1 by allowing them to
operate amalgam separators at a lower efficiency than the separators required under phase 2.
Duluth, Minnesota
In 1992, the Western Lake Superior Sanitary District ("WLSSD," i.e., Duluth) and the
Northeast District Dental Society formed a public-private partnership that taught dentists how to
recycle amalgam waste, made presentations at local dental society meetings, and prepared and
distributed written materials. As an incentive, the WLSSD purchased and installed separators at
51 dental offices, but left the largest long-term cost (recycling the amalgam) to be paid by the
dentists (Walsh, 2007). ADA attributed the success of the program to the leadership of the local
dental society, peer-to-peer interaction with area dentists (including explaining the need to
properly manage amalgam waste to prevent mercury from entering the environment and
demonstrating the proper methods for doing so), financial incentives to install amalgam
-------
Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
separators, and a discount waste disposal option through WLSSD's "Clean Shop" Program. As
of 2007, all of the dental offices had installed amalgam separators.
Wichita, Kansas
In April 2000, the Wichita Department of Water and Sewer initiated a Mercury Code of
Management Practices (CMP) for the city. The CMP requires dental offices in Wichita to be
equipped with devices to reduce the amount of amalgam discharged into POTWs. Phase 1 was
an effort to encourage voluntary use of technologies beyond the chair-side trap and vacuum filter
(e.g., an amalgam separator). Phase 2 of the program would have required mandatory separators
if the voluntary effort were not successful. Phase 2 of the program was never implemented
because originally 60 percent of the dental community complied voluntarily. According to ADA,
as of 2007, 98 percent of the 200 dental offices in the city have complied with the Mercury CMP
Program without a mandatory separator requirement (Walsh, 2007).
Massachusetts
In 2004, the Massachusetts Department of Environmental Protection (MassDEP) worked
with the Massachusetts Dental Society to establish a voluntary program for dentists to install
amalgam separators. The program used a two-phase approach:
• First, MassDEP implemented a voluntary program that encouraged dental offices to
install and use amalgam separators. The program's goals called for 50 percent
participation by January 2005, 90 percent by January 2006, and 100 percent by
January 2007.
• Second, MassDEP implemented mandatory requirements, described in Section 6.2,
for operating amalgam separators, recycling amalgam waste, and certifying
compliance.
The voluntary portion of the program reported a 75 percent participation rate for the first
year, exceeding MassDEP's goals. In April 2006, MassDEP promulgated regulations mandating
that most dental offices install separators. Dentists who had complied with the voluntary program
were rewarded with an exemption from the regulation (i.e., record keeping and reporting) until
2007 or 2010, depending on how early they had complied. In addition, dentists who installed
separators under the voluntary program were permitted to continue operating their separators at
95 percent efficiency. The regulation required all newly installed amalgam separators to operate
at 98 percent efficiency (MassDEP, 2007).
6-15
-------
Table 6-7. Summary of Voluntary Programs for Reducing Dental Amalgam Releases to Wastewater
State (Jurisdiction)
Date
Description
Participation Rate
Verification of Participation
California
(Palo Alto, San
Francisco, and
Central Contra
Costa)
No
information
Voluntary installation of amalgam separators and
implementation of BMPs.
65%
Survey conducted by sanitation
districts in 2000.
Kansas
(City of Wichita)
April 2000
Developed a Mercury Code of Management Practices
(CMP).
Encouraged dentists to use technologies beyond chair-
side trap and vacuum filter (e.g., amalgam separator).
Planned to require mandatory installation of amalgam
separators if participation in the voluntary program
had been low, but found that a mandatory requirement
was not necessary.
98% (out of 200 offices)
No information.
a
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o
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B
fa
H.
r
o
a
I
Massachusetts
(MA Dental
Society)
2004
Goals were to have 50% of dentists install amalgam
separators by January 2005, 90% participation by
2006, and 100% participation by 2007.
MA later implemented mandatory requirements for
amalgam separators.
April 2005 — 75%
No information.
Minnesota
(MN Dental
Association)
2001
Voluntary installation of amalgam separators.
85% of dentists have committed
to installing separators.
No information.
Minnesota (City of
Duluth)
2001-2003
Sanitation district purchased and installed amalgam
separators in dental offices.
Dentists are responsible for cost of recycling.
The sanitation district and local dental society also
provided education on how to recycle amalgam waste,
trained personnel at dental offices, prepared written
materials, and made presentations at dental society
meetings.
100%
Sanitation district paid for and
oversaw the installation of all
amalgam separators.
Minnesota
(Minneapolis, St.
Paul)
2003
Voluntary installation of amalgam separators.
700 clinics participated in program.
The voluntary program was accompanied by a threat
of eventual regulation and an industrial permit
requirement.
99% of the clinics eligible for
the program installed
separators.
No information.
o'
hd
3
OQ
-------
Table 6-7. Summary of Voluntary Programs for Reducing Dental Amalgam Releases to Wastewater
State (Jurisdiction)
Date
Description
Participation Rate
Verification of Participation
Missouri
(Springfield)
2006
University of Missouri conducted a study to
determine whether voluntary BMPs could
significantly reduce mercury discharges from dental
offices.
Offered a half-day training course on BMPs.
Also sent outreach materials via mail to local
members of the dental society.
Collected wastewater samples to determine mercury
reductions.
254 members in the local dental
society.
54 (21%) of local dentists
attended the half-day training
session on BMPs.
76 (30%) of dentists indicated
that they had implemented
BMPs as a result of outreach.
Very few dentists installed
amalgam separators.
UM sent a follow-up survey to the
254 members of the local dental
society.
a
o'
o
o'
B
fa
H.
r
o
a
I
Oregon
(City of Corvallis)
2003
Voluntary installation of amalgam separators and
implementation of BMPs.
Corvallis was awarded EPA's 2006 National First
Place Clean Water Act Recognition Award for
Pretreatment Program Excellence.
100%
No information.
Washington
(WA Dental
Association)
August
2003
Voluntary installation of amalgam separators and
implementation of other BMPs.
80% and anticipates an
additional 16%
No information.
Washington
(Seattle and King
County)
No
information
Significant outreach to dental offices on proper
management of scrap amalgam, proper use of chair-
side traps and pump filters to manage waste, and
amalgam separators.
Participation rate was so low that King County
decided to implement a mandatory program.
<50% managed scrap amalgam
properly.
25% installed amalgam
separators.
10% contracted with waste
haulers.
King County:
Made unannounced visits to 212
dental offices.
Contacted separator vendors to
obtain lists of dental office
customers.
Contacted waste haulers and mail-
away firms to obtain lists of
dental office customers.
Wisconsin
(Madison)
1997
Encouraged use of amalgam separators through
outreach to dentists.
Section 6.4.1 describes the mandatory program
implemented by the locality.
23 of 103 dentists in the area
(22%).
Surveyed local dentists to
determine how many clinics use
and/or remove amalgam and how
many had installed amalgam
separators.
o'
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3
OQ
Sources: Larry Walker Associates, 2002; MassDEP, 2007; MU Extension, 2007; Walsh, 2007; KCWTD, 2007; MMSD, 2008.
-------
Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
6.4.2 Voluntary Programs with Low Participation Rates
Two voluntary programs had participation rates below 50 percent. Similar to the
programs with high participation rates, these programs conducted extensive outreach to local
dentists to educate dentists on BMPs and the use of amalgam separators. Despite this effort, one
of the two programs discussed in this section decided to implement mandatory requirements for
BMPs and amalgam separators due to the low level of participation in the voluntary program.
Seattle and King County
In 1995, the Seattle-King County Dental Society set up a standing committee to work
with the King County government. These partners met several times a year and pursued a
number of activities listed below (Cain and Krauel, 2004). The Society won a regional
environmental achievement award for its efforts to educate its members concerning mercury in
dental wastewater.
• Developing a poster and a handbook for dentists;
• Writing articles for a dental journal;
• Mailing information to all members;
• Co-sponsoring a free waste pick-up event; and
• Presenting a "Green Dentistry" session at two Pacific Northwest Dental Conferences.
Other efforts undertaken independently by King County included:
• Advertisements seeking to educate dentists;
• Outreach to dental supply houses;
• Outreach to vocational/technical programs for dental assistants;
• Cash rebates for purchase of amalgam separators (up to $500);
• Technical assistance visits to dental offices; and
• Promotion of dentists as "EnviroStars."
During the fall of 1999 and spring of 2000, King County evaluated its voluntary dental
program by conducting random visits to 212 dental offices and collecting data on the disposal of
scrap amalgam, amalgam from chair-side traps, and pump filter sludge. King County also
contacted separator vendors to obtain lists of dental offices that had purchased and installed
separators, and of waste haulers and mail-away firms to obtain lists of dental offices with waste
management contracts.
King County's evaluation showed that the six-year voluntary program achieved the
following results (Cain and Krauel, 2004):
• Less than half of dentists in the King County service area properly managed scrap
amalgam.
• Less than 25 percent of dentists properly managed chair-side trap and pump filter
waste.
-------
Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
• Only 25 dental offices installed amalgam separators (2.5 percent of those estimated to
place and/or remove amalgam).
• Approximately 10 percent of dental offices contracted with waste haulers and/or
mail-away firms.
• Hundreds of pounds of mercury from dental amalgams were still being disposed of
annually in garbage, "red bags," sewers, and "unknown" places.
• The costs for King County's voluntary program totaled over $250,000. During 1995-
2001, the program spent an estimated $4,500 on advertisements, $24,000 on the
production of a poster and handbook, $65,000 on equipment rebates, $63,500 on field
visits, and $100,000 for staff time.
Due to the lack of success of this voluntary program, King County began a mandatory
program as of July 2003. Table 6-7 describes the mandatory regulations (KCWTD, 2007).
Springfield, Missouri
The Springfield program included extensive outreach to local dentists and was very
successful in getting dentists to follow voluntary BMPs. However, the program was unsuccessful
in getting dentists to install amalgam separators. The program staff concluded that amalgam
separators were not installed because they are not required.
In 2006, the University of Missouri (MU Extension) began a study to determine whether
dental offices could significantly reduce their mercury discharges through voluntary BMPs.
Springfield was selected for the pilot study based on interest and commitment of staff resources
from the Springfield Public Works Department and the Greater Springfield Dental Society
(GSDS) (MU Extension, 2007). The discussion of this study presented in this section focuses on
participation rates for the voluntary program. Section 7 of this document discusses effectiveness
of BMPs on reducing mercury concentrations at POTWs.
MU distributed a questionnaire to Springfield dentists in February 2006 to collect
baseline data on amalgam use and management practices. The questionnaire was sent to 123
dentists and there were 48 responses (39 percent). MU then offered area dentists a half-day
training course on BMPs for dental amalgam. Eighty dentists and dental office staff representing
54 local dental offices attended the training. Participants received a DVD, a wall poster with
BMPs, a brochure of other available resources, and other written materials including:
• Dental mercury hygiene recommendations;
• ADA Guidelines on Amalgam Accumulations in Dental Office Plumbing;
• ADA Summary of Recent Study of Dental Amalgam in Wastewater;
• The Missouri Department of Natural Resources' determination of status and options
for various types of dental amalgam waste; and
• A list of amalgam recyclers.
MU Extension also sent training materials by mail to dentists who did not attend the
course.
-------
Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
One year later, MU Extension distributed a follow-up questionnaire to 254 members of
the GSDS to measure any changes in management practices that resulted from MU's education
efforts. The response rate was 30 percent (76 dental offices). The comparison of responses on
reported dental amalgam management practices before and after intervention showed that the
BMP training and education efforts may have succeeded in changing some practices:
• Dental amalgam use decreased 5 percent from the previous year.
• Improper disposal of capsules in regular waste decreased after the training and
education, while the number of dentists reporting setting amalgam capsules aside for
pickup by an amalgam recycler increased significantly.
• The collection and recycling of scrap amalgam increased significantly after BMP
training while the improper disposal decreased.
• The amount of amalgam scrap disposed of as medical waste after the BMP training
increased slightly. This finding may indicate a need for additional education for
dental office staff and better labeling and instruction from medical waste management
companies.
• Use of chair-side traps increased from the year before; the practice of disposing of
trap contents with regular waste decreased.
• More of the dentists who used pump filters reported placing filter contents in a
container with medical waste. Also reported was a slight increase in placing filter
contents in a container for pickup by an amalgam recycler. Fewer dentists reported
that they place filter contents in regular office waste.
• More dentists reported that they disinfected extracted teeth with amalgam restorations
and set them aside for an amalgam recycler.
• More dentists reported using an amalgam recycler and that their recycler also picked
up medical waste. However, the majority of dentists reported that they were unable to
recycle amalgam waste because they could not locate a recycler in their area, locate a
recycler to pick up small quantities of dental amalgam waste, find a method for
shipping waste, or afford recycling amalgam.
According to the results of the survey, MU's efforts were successful in educating dentists
on BMPs. However, the majority of the dentists in the Missouri/Springfield area did not use
amalgam separators prior to outreach and did not install amalgam separators after MU conducted
its outreach. MU concluded that very few dentists use amalgam separators because they are not
required in Missouri or Springfield (MU Extension, 2007).
6.4.3 Summary of Participation Rates in Voluntary Programs
Participation rates in voluntary programs are highly variable, ranging from as high as 100
percent of dentists in a community to as low as approximately 20 percent. Several programs that
experienced low participation rates conducted extensive outreach and had frequent interaction
with dentists. Therefore, the level of participation did not necessarily correspond to the level of
outreach and education. In a study prepared for the Association of Metropolitan Sewerage
Agencies (AMSA), the author noted that during the first year of implementation, regulatory
programs will have higher participation rates than voluntary programs. However, over time (5 to
6^20
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Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
10 years), participation rates for well-implemented voluntary programs will be similar to
participation rates for mandatory programs (Larry Walker Associates, 2002).
The highest participation percentages were seen for voluntary programs that included the
threat of a mandatory second phase. Examples of the mandatory second phase requirements
included more stringent requirements for reporting, or the requirement for higher amalgam
separator efficiency standards. To avoid the more stringent mandatory requirements, dental
offices usually opted to comply with the voluntary requirements. Often, the mandatory second
phase of the program was not ultimately implemented. In addition, voluntary control programs
that directly purchased amalgam separators for the dentists to install were very successful.
The level of interaction between the program partners and local dentists varies greatly
from program to program. Follow-up activities to verify participation include conducting
surveys, visiting dental offices, and contacting amalgam separator vendors and waste haulers for
lists of customers.
6.5 REFERENCES
ADA (American Dental Association). 2007. Best Management Practices for Amalgam Waste.
Updated July 2007. Document Control Number (DCN) DAGO 165.
ADA. 2010. ADA Principles to be used to Develop Mandatory Separator Pretreatment Rule.
Washington, DC. October 29. DCN DA00137.
ADA News. 2013. ADA Business Resources endorses HealthFirst's Amalgam Recovery
Program. November 2. DCN DA00245.
ADA Business Resources. 2014. HealthFirst Amalgam Recovery Program. Accessed 2014. DCN
DA00246.
ALISON (Alabama Legislative Information System Online). 2007. Regular Session 2004. DCN
DA00210.
Anderson, N. 2007. Statement of Norris Anderson, Ph.D., Director, Office of Science and Health
Coordination, FDA. November 14. DCNDA00204.
Arkansas. 2003. House Bill 1309: An Act to Reduce the Incidence of Mercury Poisoning in
Arkansas, and for Other Purposes. State of Arkansas 84th General Assembly, Regular
Session, 2003. DCNDA00187.
Behm, D. 2008. Dentists Filtering Out Mercury but Nearly One-fifth Miss MMSD Deadline.
Milwaukee Journal Sentinel. February 9. DCN DA00203.
Cain, A. and R. Krauel. 2004. U.S. EPA and Environment Canada. Options for Dental Mercury
Reduction Programs: Information for State/Provincial and Local Governments. A Report
of the Binational Toxics Strategy Mercury Workgroup. August 4. DCN D AGO 132.
California Legislative Counsel. 2005. Complete Bill History, Bill Number: AB No. 966.
http://www.leginfo.ca.gov/pub/05-06/bill/asm/ab 0951-
1000/ab 966 bill 20060929_history.html. DCN DA00211.
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Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
CTDEP. 2006. Dental Use of Mercury. December 18.
http://www.ct.gov/dep/ cwp/ view.asp?a=2708&q= 323994&depNav GID=1638. DCN
DA00188.
District of Columbia Water and Sewer Authority. 2012. Notice of Final Rulemaking Vol 59 No
6. Washington DC. February. DCN DA00254.
EBMUD (East Bay Municipal Utility District). 2005. Pollution Prevention Program. January.
DCNDA00179.
FDA (U.S. Food and Drug Administration). 2008. Questions and Answers on Dental Amalgam.
DCNDA00218.
FLDEP (Florida Department of Environmental Protection). 2001. Best Management Practices for
Scrap Dental Amalgam: Guidelines for Dental Offices. October. DCNDA00178.
Grubbs, G. 2003. Statement of Geoffrey Grubbs, Director, Office of Science and Technology,
United State Environmental Protection Agency, before the Subcommittee on Wellness
and Human Rights of the Committee on Government Reform, United States House of
Representatives. October 8. DCN DA00174.
HERCenter (Healthcare Environmental Resource Center). 2008. Best Management Practices for
Common Dental Office Wastes, http://www.hercenter.org/dentistwastes.cfm. DCN
DA00208.
ISDA (Idaho State Dental Association). 2008. Best Management Practices (BMPs) for Dental
Offices. DCN DA00205.
KCWTD (King County Wastewater Treatment Division). 2007. King County Regulations for
Dental Wastewater Discharged to the Sewer. May 16. DCN DA00190.
Lamperti, L. 2007. City of Corvallis' Comments on EPA's Preliminary 2008 Effluent Guidelines
Program Plan. December 21. DCN DA00235.
Larry Walker Associates. 2002. Mercury Source Control and Pollution Prevention Program
Evaluation. Prepared for AMSA. March (Updated July). DCN DA00006.
Louisiana Legislature. 2006. The Louisiana Mercury Risk Reduction Act. Act No. 126. DCN
DA00068.
Maine DEP (Department of Environmental Protection). 2005. Dental Amalgam Separator
Systems (website), http://www.maine.gov/dep/water/wd/amalgam-separators/. DCN
D AGO 193.
Maine Legislature. 2001. Chapter 16-B: Mercury-Added Products and Services Heading: PL
1999, C. 779. Maine Revised Statues Title 28: Waters and Navigation.
http://www.mainelegislature.org/legis/statutes/38/title38secl661-c.html. DCN DA00069.
MassDEP (Massachusetts Department of Environmental Protection). 2007. Dental
Amalgam/Mercury Recycling Program. DCN DA00191.
6^22
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Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
MDA (Minnesota Dental Association). 2003. Re: Amalgam Recovery. Take Preventive Action
Now. Capture Amalgam So It Doesn't Release Mercury. March.
http://www.mndental.org/client_files/documents//amalgam_recovery.pdf. DCN
DA00192.
MIDEQ (Michigan Department of Environmental Quality). 2008. Dental Mercury Amalgam
Separators, Public Act 503 of 2008. DCN DA00071.
MMSD (Madison Metropolitan Sewerage District). 2008. MMSD Mercury Pollutant
Minimization Program DCN DA00220.
MMSD and University of Wisconsin Extension. 2006. Amalgam Management for Dental
Offices. Milwaukee, WI. DCN DA00232.
MU Extension (University of Missouri Extension Environmental Assistance Center). 2007.
Maximizing Voluntary Reductions in Dental Amalgam Mercury: Reduction in Mercury
Discharges. EPA#E0000127. Pl-98765101-0. November. DCNDA00223.
MU Extension. 2011. P2: Dental Practices Managing Dental Amalgam. DCN DA00134.
NEORSD (Northeast Ohio Regional Sewer District). 2007. Mercury Program: Annual Report
Form for Dental Care Practices, 2006. DCNDA00213.
New Mexico Legislature. 2013. Senate Bill 099: Dental Amalgam Waste Reduction.
http://www.nmlegis.gov/Sessions/13%20Regular/final/SB0099.pdf. DCN DA00241.
NHDES (New Hampshire Department of Environmental Services). 2002. Best Management
Practices for Dental Offices in New Hampshire. January. DCN DA00194.
NJR (New Jersey Register). 2007. Requirements for Indirect Users — Dental Facilities. 39 NJR
4117(a). October 1. DCNDA00222.
NYDEC. 2007. Managing Dental Mercury, http://www.dec.ny.gov/chemical/8513.html. DCN
D AGO 195.
Oregon State Legislature. 2007. Senate Bill 704: An Act Relating to Mercury in Dental
Wastewater. June.
https://olis.leg.state.or.us/liz/2007Rl/Downloads/MeasureDocument/SB704. DCN
DA00196.
OSHA (Occupational Safety and Health Administration). 1997. The Dental Industry's Concerns
Regarding Compliance with Certain Provisions of the Hazard Communication Standard
(HCS). Letter to the American Dental Trade Association. February 6. DCN DA00214.
Palo Alto (City of Palo Alto Regional Water Quality Control Plant). 2007. Advanced Mercury
Source Control Study: 2006 Annual Report of Activity. February. DCNDA00182.
RIDEM (Rhode Island Department of Environmental Management). 2007. Mercury in Dental
Amalgam, http://www.dem.ri.gov/topics/mercury.htm. DCN DA00207.
6^23
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Section 6 - Current National, State, and Local Dental Mercury Reduction Programs
U.S. EPA. 2005. POTWMercury Control Strategy. May 9. DCN DA00180.
Uva, T.P. 2007. Narragansett Bay Commission's (NBC) Comments on EPA's Preliminary 2008
Effluent Guidelines Program Plan. December 27. DCN DA00237.
VTDEC (Vermont Department of Environmental Conservation). 2006. Environmental
Management for Dental Offices. September 19. http://www.mercvt.org/dental/index.htm.
DCNDA00197.
WADOE (Washington State Department of Ecology). 2005. Manage Dental Waste.
http://www.ecv.wa.gov/mercurv/mercurv dental bmps.html. DCN DA00080.
Walsh, William. 2007. The American Dental Association's (ADA) Comments on EPA's Study
of a Pretreatment Requirement for Dental Amalgam. Pepper Hamilton, LLP. December
21.DCNDA00238.
6-24
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Section 7 - Treatment Technologies and Best Management Practices (BMPs)
SECTION 7
TREATMENT TECHNOLOGIES AND BEST MANAGEMENT
PRACTICES (BMPs)
Dental offices employ various technologies and approaches for reducing or eliminating
pollutant discharges. As described earlier, some dental offices do not install or remove amalgam.
For those dental offices that do place or remove amalgam, as described in Section 5, chair-side
traps and vacuum pumps reduce the pollutants in dental amalgam discharges. Further reductions
can be achieved by adding amalgam separators. To reduce the "dissolved" portion of metals,
dental offices can incorporate polishing technologies. Finally, as described in Section 6, best
management practices (BMPs) are integral to reducing pollutants in dental discharges.
This section describes amalgam separators and polishing, including information on
treatment efficiency. It also discusses BMPs that EPA identified to reduce the discharge of dental
amalgam resulting from activities not directly related to amalgam restoration or removal.
7.1 AMALGAM SEPARATORS
An amalgam separator is a device designed to remove solids (such as amalgam) from
dental office wastewater. Dental wastewater that goes into the chair-side cuspidors might not go
through the amalgam separator, but dental practices can connect the chair-side drain to the
vacuum system.13 The amalgam separator is placed at a 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 office's vacuum to draw
wastewater into the separator. However, the separation of solids from the wastewater and the
flow of the wastewater out of the separator will depend on the design of the separator. A typical
plumbing configuration for a dental office outfitted with an amalgam separator is shown earlier
in this document, in Figure 5-1. Prior to wastewater entering the amalgam separator, some dental
amalgam is removed by the chair-side traps and vacuum filter traps. Dentists maintain the traps
by dumping out the solid particles collected by them into a bucket or other storage container,
then properly disposing of the dental amalgam waste (ERG and SolmeteX, 2011). The
wastewater flow rate determines how often filters and traps need to be cleaned/replaced (Walsh,
2007).
7.1.1 Treatment Process, Design, and Operation
The configuration, size, and operation of the dental office all affect the choice of
separator design. Amalgam separators can use sedimentation, filtration, centrifugation, ion
exchange, or a combination of some or all of these methods to remove dental amalgam (ADA,
2007a). Virtually all amalgam separators currently on the market use sedimentation processes
(with or without filtration) to settle out the solids from the wastewater. The high specific gravity
of amalgam causes it to settle readily from suspension in wastewater, which allows the dental
office wastewater to be treated effectively by sedimentation (Fan et al., 2002). Baffles or tanks
can reduce the speed of the wastewater flow, allowing more amalgam particles to settle out.
13
Gravity -feed amalgam separators might also be installed at dental offices.
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Section 7 - Treatment Technologies and Best Management Practices (BMPs)
After the solids settle, the wastewater is either pumped out, decanted during servicing, or pulled
through the separator. Sedimentation-based separators are the simplest types of separators to
operate.
Filtration can enhance solids removal in sedimentation-based amalgam separators, or
may function as the primary treatment process of the separator (Fan et al., 2002). EPA is aware
of at least one type of separator that uses centrifugation, in which a centrifuge-based separator
spins the water and forces the heavier amalgam particles to the sides of the separator, while the
water discharges from the separator.
A few amalgam separators combine sedimentation (with or without filtration) with ion
exchange in the same unit. Ion exchange technology removes dissolved mercury by using a
chelating agent or proprietary resin. These separators often require special cleaning or additives
to maintain their efficiency. A few dental offices operate a separate ion exchange (or polishing)
system to remove dissolved mercury after the wastewater leaves the amalgam separator. See
Section 7.2.
Although none of the separators that EPA identified in the literature review added
chemicals to enhance solids removal, chemical and polymer additions have been effective in
precipitating a portion of dissolved mercury out of dental wastewater (Fan et al., 2002).
There are two common designs for amalgam separators. The first is a two-chambered
separator design that consists 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 top of the separator 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 unit. The
wastewater leaves its solids in the filter, then continues through the vacuum system and
eventually discharges from the dental office and then to the sewer. The second 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 and remains in the separator for some time, allowing the solids to settle. For either
design, when the filtration cartridge or the separator itself reaches its capacity for retained solids,
the cartridge must be replaced and/or the separator serviced by the recycling or waste vendor
(ERG, 2010 and ERG, 201 Ib).
The performance of the amalgam separator depends directly on specific operational,
maintenance, and inspection activities. 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 is vital that the unit be checked
periodically, and serviced if necessary. Manufacturers will typically recommend the frequency of
checks and service to ensure proper operation.
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Section 7 - Treatment Technologies and Best Management Practices (BMPs)
Solids collected by the amalgam separator may include dental amalgam, biological
material from patients, and any other solid material sent down the vacuum line. Manufacturer
instructions for servicing amalgam separators and for handling separator waste should be
followed. Some amalgam separator manufacturers also offer waste management services.
Services provided can include ensuring that waste collected by the separator is handled
according to state and local requirements, and providing necessary compliance documentation
for the office's recordkeeping requirements. If such services are not employed, the office should
dispose of amalgam waste in accordance with state and local requirements.
7.1.2 Standards for Amalgam Separators
Two standards are currently used to evaluate the treatment efficiency of amalgam
separators: (1) International Organization for Standardization (ISO) Standard 11143; and (2)
U.S. EPA's Environmental Technologies Verification (ETV) program.
ISO Standard 11143. The majority of amalgam separators currently on the market have
been evaluated for their ability to meet ISO 11143, the international standard for amalgam
separators used in connection with dental equipment. ISO 11143 calls for measuring amalgam
separator efficiency by evaluating the retention of amalgam. It also includes requirements that
instructional material supplied by the manufacturer include directions for use, operation, and
maintenance The standard classifies amalgam separator systems by the method of separation:
centrifugation, sedimentation, filtration, or combination of the first three methods.
ISO Standard 11143 requires that an amalgam separator remove at least 95 percent by
weight of amalgam particles (i.e., the metals that constitute the amalgam filling) when subjected
to a specific test method as detailed in the Standard. The test for determining the efficiency must
be carried out when the amalgam separator is under both empty and full conditions. The ISO test
for removal efficiency uses 10.00 grams of amalgam particles that are composed of three
portions of different sizes (ISO, 2008):
• 60 percent of the particles are 3.15 millimeters (mm) or smaller and larger than 0.5
mm.
• 10 percent of the particles are 0.5 mm or smaller and larger than 0.1 mm.
• 30 percent of the particles are 0.1 mm or smaller.
It is important to note that certification under this standard is based not on total mercury
concentration in effluent wastewater, but on particle removal. To test the efficiency of an
amalgam separator, a slurry of water and amalgam is poured into the amalgam separator and
effluent water is collected. This effluent wastewater is filtered through a series of pre-weighted
filters, the filters are dried and weighed, and the final weight of the filters is then compared
against the original weight (Batchu et al., 2006a). ISO Standard 11143 describes the set up of the
testing apparatus, installation of the amalgam separator, step by step procedures to perform the
efficiency testing, and how to determine the efficiency of the amalgam separator.
The ISO Standard 11143 also requires that amalgam separators include a warning system
to indicate when the collecting container should be emptied or replaced (before maximum
fillable volume is reached). The standard also requires an alarm system to indicate when the
collecting container has reached the maximum filling level specified by the manufacturer. The
7-3
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Section 7 - Treatment Technologies and Best Management Practices (BMPs)
alarm signal must remain activated until the dentist empties or replaces the collecting container
and/or filter. A final alarm system is also required to indicate a malfunction of the amalgam
separator.
Other requirements of the ISO Standard 11143 include a removable filling container for
the amalgam separator that the dentist can easily and safely remove without discharging any of
the contents into the public sewage system, a maximum fillable volume of the collecting
container (4 liters), and electrical safety requirements for installing an amalgam separator.
EPA/Environmental Technology Verification (ETV) Standard. The EPA/ETV program
has developed a standard more rigorous than ISO 11143. The EPA/ETV standard, "Protocol for
the Verification of Hg Amalgam Removal Technologies," uses a concentration-based criterion
and measures efficiency as a function of mercury concentration as opposed to particulate
removal (NSF International, 2001). EPA/ETV protocol recommends using Standard Methods
3500-Hg for sample collection, preservation, analysis, and storage. Standard Methods 3500-Hg
is a cold vapor atomic absorption method for determining the concentration of mercury in
potable water (APHA et al., 1998). The EPA/ETV standard protocol is not used nearly as widely
as the ISO Standard, likely due to its higher cost and the longer time required for sample
analysis. See http://www.epa.gov/etv/pubs/04_vp_mercury.pdf
7.1.3 Treatment Efficiencies for Amalgam Separators
Dental offices commonly use amalgam separators in conjunction with chair-side traps
and vacuum pump filters. Most chair-side traps can filter particles as small as 0.7 millimeter
(mm) and vacuum filter traps can capture particles as small as 0.4 mm (Fan et al., 2002). The
combined removal rate of the chair-side trap and vacuum filter is approximately 78 percent of
amalgam particles (Vandeven and McGinnis, 2005). When chair-side traps and vacuum pump
filters are used upstream of amalgam separators, the combined treatment system can achieve
removal rates exceeding 99 percent (Fan et al., 2002).
Studies have demonstrated that amalgam separators can achieve significant reductions in
the amount of mercury discharged from dental wastewater.
• A 1998 Boston University study tested three commercially available amalgam
separators that used different separation technologies, including gravity settling,
settling/filtration, and mechanical centrifuge. The particulate mercury removal
efficiencies for the three technologies ranged from 95 to 99.9 percent. However, the
study also noted that an effluent concentration of 0.2 parts per million could not be
consistently met without chemical treatment (Boston University, 1998).
• A 2001 study found that amalgam separators were able to remove 91 to 99 percent of
amalgam particles (i.e., the metals that constitute the amalgam filling), with an
average removal efficiency of 95 percent (MCES, 2001).
• EPA Region 8 has reported that a properly installed amalgam separator will achieve
removal efficiencies ranging from 95 to 99.99 percent of particulate mercury (U.S.
EPA, 2005).
7-4
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Section 7 - Treatment Technologies and Best Management Practices (BMPs)
Table 7-1 provides a non-inclusive list of 39 commercially-available amalgam separators,
including manufacturer name, the type of particulate separation technologies used, and the
amalgam removal efficiency based on ISO testing in a laboratory setting.14 As illustrated, all
separators exceeded the ISO Standard of 95 percent efficiency, 34 separators exceeded 97
percent efficiency, and 29 separators exceeded 99 percent efficiency of amalgam particle
removal. The separators described in Table 7-1 achieved an average efficiency of 98.8 percent
and a median efficiency of 99.0 percent.
Table 7-1. Efficiency and Technology of 39 Amalgam Separators
Model
A 1250
AD 1000
Amalgam Boss
Amalgam Boss
Amalgam
Collector CE18
Amalgam
Collector CE24
Amalgam
Collector CH12
Amalgam
Collector CH9
ARU-10
Asdex AS-10
Asdex AS-20
Asdex AS-20
Asdex AS-9
BU10
BU30
Catch 1000 Plus
Catch 400 Plus
Catch 9000 Plus
ECO II
Manufacturer
Air Techniques
American Dental
Accessories
M.A.R.S. Bio-Med
Processes
Hygenitek
R & D Services
R & D Services
R & D Services
R & D Services
Hygenitek
Capsule Technologies
Capsule Technologies
American Dental
Accessories
American Dental
Accessories
Dental Recycling North
America
Dental Recycling North
America
Rebec Solutions
Rebec Solutions
Rebec Solutions
Metasys, distributed by
Pure Water
Development
Treatment Technology
Centrifugation
Sedimentation, filtration,
ion exchange
Sedimentation, filtration,
ion exchange
Sedimentation, filtration,
ion exchange
Sedimentation
Sedimentation
Sedimentation
Sedimentation
Sedimentation, filtration,
ion exchange
Filtration
Filtration
Sedimentation
Filtration
Sedimentation
Sedimentation
Sedimentation
Sedimentation
Sedimentation
Sedimentation
Percentage of Amalgam
Removed (by weight) a
>99.0%
99.3%
95.0%
99.2%
99.6%
>99.9%
>99.9%
>99.9%
>99.9%
99.0%
99.0%
95.0%
99.0%
>99.9%
>99.9%
99.0%
99.0%
99.0%
97.5%
Data
Sources
6
2,7
3
1,9
1,9
1,10
1,10
1,10
5,11
1,12
1,12
1,5
7
1,8
1,8
1,13
1,13
1,13
1,4,5,10
14
Mention of product and vendor names does not constitute an endorsement by EPA.
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Section 7 - Treatment Technologies and Best Management Practices (BMPs)
Table 7-1. Efficiency and Technology of 39 Amalgam Separators
Model
Hg5
Hg5HV
Hg5 Mini
Liberty Boss
Merc II
MRU10
MRU30
MSS 1000
MSS 2000
MSS 601
Rasch 890- 1000
Rasch 890-1500
Rasch 890-4000
Rasch 890-6000
Rasch 890-7000
Rasch AD- 1500
REM2000
Series/Catch
1000
REM2000
Series/Catch 400
REM2000
Series/Catch
9000
Manufacturer
SolmeteX
SolmeteX
SolmeteX
M.A.R.S. Bio-Med
Processes
Bio-Sym Medical
Dental Recycling North
America
Dental Recycling North
America
Maximum Separation
Systems
Maximum Separation
Systems
Maximum Separation
Systems
AB Dental Trends
AB Dental Trends
AB Dental Trends
AB Dental Trends
AB Dental Trends
American Dental
Accessories
Rebec Solutions
Rebec Solutions
Rebec Solutions
Treatment Technology
Sedimentation, filtration,
chemical binding
Sedimentation, filtration
Sedimentation, filtration
Sedimentation, filtration,
ion exchange
Sedimentation, filtration,
ion exchange
Sedimentation, filtration,
ion exchange
Sedimentation, filtration
Sedimentation, filtration
Sedimentation, filtration
Sedimentation, filtration
Sedimentation, filtration,
ion exchange
Sedimentation, filtration,
ion exchange
Sedimentation, filtration,
ion exchange
Sedimentation, filtration,
ion exchange
Sedimentation, filtration,
ion exchange
Sedimentation
Sedimentation
Sedimentation
Sedimentation
Median
Percentage of Amalgam
Removed (by weight) a
99.0%
98.5%
99.4%
99.4%
98.2%
>99.9%
>99.9%
99.5%
98.9%
95.0%
98.9%
98.0%
>99.9%
98.0%
98.0%
95.0%
99.7%
99.6%
99.6%
99.0%
Data
Sources
1,14
1,14
1,14
1,15
5,9
2,8
8
2,5,9
2,4,5
3,5
2,9
1,16,17
2,4
1,16,17
1,16,17
1,5
1,13
1,13
2,13
a — This efficiency is based on the percentage of mercury in the form of dental amalgam removed by weight, as instructed in
ISO Standard 11143.
Sources: (1) - U.S. Air Force, 2011; (2) - MCES, 2009; (3) - MMSD and University of Wisconsin-Extension, 2006; (4) - Fan et
al, 2002; (5) - McManus and Fan, 2003; (6) - ERG and Air Techniques, 2011; (7) - ERG and American Dental Accessories,
2011; (8) ERG and DRNA, 2011; (9) Batchu, et. al., 2006a; (10) Cain and Krauel, 2004; (11) Condrin, 2004; (12) Capsule
Technologies, 2011; (13) ERG and Rebec Solutions, 2011; (14) ERG and SolmeteX, 201 Ib, (15) MARS Bio Med Processes,
2012; (16)Haraldsson andNyman, 2001; (17)HaraldssonandNyman, 2003.[Summary of analysis included in ERG, 2014].
7-6
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Section 7 - Treatment Technologies and Best Management Practices (BMPs)
7.2 POLISHING
Mercury is both dissolved and suspended in dental amalgam. More than 99.6 percent is
suspended (Stone, 2004). 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 treatment system that removes dissolved mercury from wastewater
after the wastewater has gone through the separator.
Dissolved mercury has a tendency to bind with other chemicals, resulting in a charged
complex. Ion exchange separates these charged amalgam particles from the wastewater. Ion
exchange does not rely on physical settling of particles, and is advantageous because it removes
very small amalgam and ionic mercury particles. Sedimentation (with or without filtration) alone
does not remove dissolved mercury. Ion exchange might be useful, for instance, in municipalities
that have concentration limits on mercury (McManus and Fan, 2003). EPA is not aware of any
state regulations that require ion exchange.
For ion exchange to be most effective in removing dissolved mercury, the incoming
wastewater should first have the solids removed and then be oxidized in order for the resin (or
other capturing material) to capture the dissolved mercury. 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 to remove both suspended and dissolved mercury. Dental offices needing to employ
polishing would likely need to add a separate ion exchange unit to remove additional mercury
from the waste stream after it leaves the amalgam separator.
As explained above, ISO certification testing is based on an evaluation of the removal of
amalgam in a laboratory setting and does not differentiate between the suspended and dissolved
forms. In order to understand more fully the reductions in dissolved mercury that can be
achieved with the addition of ion exchange polishing, EPA reviewed available performance data
from actual installations of ion exchange units and to amalgam separators in dental offices. EPA
found the use of polishing is limited to a handful of dental offices and found just one study of
polishing systems. This study evaluated the additional efficacy provided by polishing at two
dental facilities that were responding to sanitation district concerns over their mercury
discharges. In both cases, the polishing systems were installed (as is usual) to treat wastewater
after it left the amalgam separator.
Preliminary EPA Region 8 audits showed the total additional mercury reductions
achieved by the polishing step were typically on the order of 0.5 percent (Garcia, 2009). This is
not surprising since, as indicated above, dissolved mercury is a very small percentage of the total
amount of mercury in dental amalgam. It is unclear whether any solid mercury was converted to
dissolved mercury in these two systems, and additional monitoring data are not yet available.
EPA also found limited data on the costs of polishing systems (ERG, 201 la).
7.3 BEST MANAGEMENT PRACTICES
Most state and local dental mercury reduction programs include BMPs. Most are based
on the American Dental Association's BMPs developed in 2003 (ADA, 2007b), discussed in
-------
Section 7 - Treatment Technologies and Best Management Practices (BMPs)
6.1.4. After reviewing ADA's BMPs and those of state and local programs, EPA decided to
include certain operational, maintenance, and inspection practices in its proposed rule because
these practices have a significant impact on how effectively amalgam separators function to
achieve their certified performance levels.
EPA proposes to require line cleaners that do not contain bleach and are of neutral pH.
Bleach and other corrosive cleaners can solubilize bound mercury. If dental practices use
corrosive cleaners to clean vacuum lines leading to an amalgam separator, the line cleaners may
solubilize any mercury that the separator has captured, resulting in increased mercury discharges
(Cain and Krauel, 2004; Batchu et al., 2006b).
EPA's second proposed BMP prohibits the flushing of scrap amalgam (contact and non-
contact) into drains that do not lead to an amalgam separator (e.g., a cuspidor not attached to the
vacuum line), and into general use sinks. Sources of dental amalgam include, but are not limited
to, chair-side traps, screens, vacuum pump filters, dental tools, or collection devices. This rule
limits additional avenues through which mercury might be discharged from dental offices.
7.4 REFERENCES
ADA (American Dental Association). 2007a. ADA Professional Product Review. Document
Control Number (DCN) DA00043.
ADA. 2007b. Best Management Practices for Amalgam Waste. Updated July 2007. DCN
D AGO 165.
APHA, AWWA, and WEF (American Public Health Association, American Water Works
Association, and Water Environment Federation). 1998. Standard Methods for the
Examination of Water and Wastewater. DCN DA00216.
Batchu, H., D. Rakowski, P.L.Fan, and D.M. Meyer. 2006a. Evaluating Amalgam Separators
Using an International Standard. Journal of the American Medical Association, 137:999-
1005. DCN D AGO 183.
Batchu, H., H.N. Chou, D. Rakowski, and P.L. Fan. 2006b. The Effect of Disinfectants and Line
Cleaners on the Release of Mercury from Amalgam. Journal of the American Dental
Association 137(10): 1419-1425. DCNDA00215.
Boston University. 1998. A New Prescription: Pollution Prevention Strategies for the Health
Care Industry. October 7. DCN DA00170.
Cain, A. and R. Krauel. 2004. U.S. EPA and Environment Canada. Options for Dental Mercury
Reduction Programs: Information for State/Provincial and Local Governments. A Report
of the Binational Toxics Strategy Mercury Workgroup. August 4. DCN D AGO 132.
Capsule Technologies. 2011. Capsule Technologies—AS-9. DCNDA00226.
Condrin, A.K. 2004. The Use of CD A Best Management Practices and Amalgam Separators to
Improve the Management of Dental Wastewater. Journal of the California Dental
Association, 32(7):583-592. DCNDA00024.
-------
Section 7 - Treatment Technologies and Best Management Practices (BMPs)
ERG (Eastern Research Group). 2010. SolmeteX meeting minutes for 15 December 2010.
Chantilly, VA. DCNDA00081.
ERG. 201 la. Polishing System for Removing Dissolved Mercury Review (revised
memorandum). Chantilly, VA. May 23. DCN DAGO 122.
ERG. 201 Ib. Dental Recycling North America, Inc. (DRNA) Meeting Minutes for 19 January
2011. March 23. DCNDA00059.
ERG. 2014. Amalgam Separator Treatment Efficiencies. MS Excel™ file. September. DCN
DA00233.
ERG and Air Techniques. 2011. Notes from telephone conversation between Kimberly Landick,
ERG, and Air Techniques. March 2, 2011: Subject Amalgam Separator Questions. DCN
DA00060.
ERG and American Dental Accessories. 2011. Email correspondence between Kimberly
Landick, ERG, and American Dental Accessories. February 28, 2011: Subject Request
for Amalgam Separator Information. DCN DA00061.
ERG and DRNA. 2011. Notes from telephone conversation between Kimberly Landick, ERG,
and Marc Sussman and Darwin Moreira, DRNA. March 1, 2011: Subject Amalgam
Separator Questions. DCN DA00062.
ERG and Rebec Solutions. 2011. Notes from telephone conversation between Kimberly Landick,
ERG and Rebec Solutions, March 2, 2011: Subject Amalgam Separator Questions. DCN
DA00063.
ERG and SolmeteX. 2011. Notes from telephone conversation between Kimberly Landick, ERG
and SolmeteX, May 10, 2011: Subject Polishing System for Removing Dissolved
Mercury. DCNDA00120.
ERG and SolmeteX. 201 Ib. Notes from telephone conversation between Kimberly Landick,
ERG and SolmeteX, March 2, 2011: Subject Amalgam Separator Questions. DCN
DA00064.
Fan, P.L., H. Batchu, H.N. Chou, W. Gasparac, J. Sandrik, and D.M. Meyer. 2002. Laboratory
Evaluation of Amalgam Separators. Journal of the American Medical Association
133:577-584. DCNDA00008.
Garcia, A. 2009. EPA Audit Follow-Up Report. U.S. EPA Region 8. September 15. DCN
DA00164.
Haraldsson, C. and P. Nyman. 2003. Test of separation efficiency according to SS-EN ISO
11143. SP Swedish National Testing and Research Institute. June 13. DCN DA000228.
Haraldsson, C. and P. Nyman. 2001. Test of separation efficiency according to SS-EN ISO
11143. SP Swedish National Testing and Research Institute. October 2. DCN DA00229.
7-9
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Section 7 - Treatment Technologies and Best Management Practices (BMPs)
ISO (International Organization for Standardization). 2008. ISO 11143 Dentistry—Amalgam
Separators, Second Edition. Geneva, Switzerland. DCNDA00138.
MARS Bio Med Processes. 2012. Liberty Boss. DCNDA00231.
MCES (Metropolitan Council Environmental Services). 2001. Evaluation of Amalgam Removal
Equipment and Dental Clinic Loadings to the Sanitary Sewer. December 21. DCN
DA00007.
MCES. 2009. Revised - Features of Approved Amalgam Separators. March.
http://www.mntap.umn.edu/healthcarehw/Dental/MCES-
MDA%20Approved%20Amalgam%20Separators.%20March%202009.pdf DCN
DA00070.
McManus, K.R., and P.L. Fan. 2003. Purchasing, Installing and Operating Dental Amalgam
Separators. Journal of the American Dental Association 134:1054-1065. DCNDA00162.
MMSD and University of Wisconsin Extension. 2006. Amalgam Management for Dental
Offices. http://www4.uwm.edU//shwec/publications/cabinet/pdf/DentalAmalgam2.pdf
DCN DA00232.
NSF International (National Sanitation Foundation). 2001. Protocol for the Verification of
Mercury Amalgam Removal Technologies. DCN DA00176.
Stone, M.E. 2004. The Effect of Amalgam Separators on Mercury Loading to Wastewater
Treatment Plants. Journal of the California Dental Association 32(7):593-600. DCN
DA00018.
U.S. Air Force. 2011. Synopsis of Dental Amalgam Separators. January 24. Dental Evaluation
and Consultation Service.
http://airforcemedicine.afms.mil/idc/groups/public/documents/afms/ctb_124864.pdf
DCN DA00079.
U.S. EPA. 2005. POTWMercury Control Strategy. May 9. DCN DA00180.
Vandeven, J., and S. McGinnis. 2004. Cost-Effectiveness of Removing Amalgam from Dental
Wastewater. California Dental Association Journal 32(7):564-573. DCNDA00021.
Vandeven, J., and S. McGinnis. 2005. An Assessment of Mercury in the Form of Amalgam in
Dental Wastewater in the United States. Water, Air and Soil Pollution 164:349-366. DCN
D AGO 163.
Walsh, William. 2007. The American Dental Association's (ADA) Comments on EPA's Study
of a Pretreatment Requirement for Dental Amalgam. Pepper Hamilton, LLP. December
21.DCNDA00238.
7-10
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Section 8 - Regulatory Options
SECTION 8
REGULATORY OPTIONS
EPA identified one technology that is available and has been demonstrated to control
dental amalgam discharges from the Dental Category: amalgam separators. EPA further
identified best management practices (BMPs) that would ensure the effectiveness of the
technology and would further reduce discharges of dental amalgam not captured by an amalgam
separator.
8.1 PRETREATMENT STANDARDS FOR EXISTING SOURCES (PSES)
EPA developed one option based on proper operation and maintenance of amalgam
separators that achieve a 99.0 percent reduction of amalgam from amalgam process wastewater,15
along with BMPs. Dental offices can comply with the numeric pretreatment standard for existing
sources (i.e., 99.0 percent reduction in amalgam discharges) by installation, proper operation,
and proper maintenance of an amalgam separator certified to meet 99.0 percent 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. Dental offices would also be able to meet the standard by certifying that they do not
place or remove amalgam.16
EPA finds that the proposed technology basis is "available," as that term is used in the
Clean Water Act (CWA) because it is readily available and feasible for all dental offices. The
American Dental Association (ADA) recommends its dentists to use the technology on which the
rule is based (i.e., amalgam separators and BMPs). Further, 40 percent of dental offices 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 that this is a low-cost technology with an approximate average annual cost of
$700 per office17 (U.S. EPA, 2011). EPA's economic analysis of these costs in relation to the
overall income of the regulated entities show that this proposed rule is economically achievable
(see Section 10). Finally, EPA also examined the non-water-quality environmental impacts of the
proposed rule and found them to be acceptable (see Section 14).
EPA is not proposing to establish pretreatment standards based on technologies that
remove dissolved mercury, i.e., polishing. None of the states with mandated requirements to
reduce dental mercury discharges requires polishing. EPA also lacks adequate performance data
to assess the efficacy of polishing or its availability for nationwide use. EPA's current
information suggests that polishing only achieves incremental removals over the selected
15 Amalgam process wastewater means any wastewater generated and discharged by a dental discharger through the
practice of dentistry that may contain dental amalgam.
16 Dentists that elect to certify that they do not install or remove amalgam will be exempt from any further
requirements of the proposed rule. See 40 CFR 441.10. 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 to these infrequent emergency treatments, to preclude such dentists from certifying.
17 This estimate reflects the average annualized cost for dentists that do not currently have amalgam separators.
JM
-------
Section 8 - Regulatory Options
amalgam separator technology of less than one-half percent of total mercury (Garcia, 2009).
While very small amounts of mercury can have environmental effects, EPA lacks sufficient
evidence to assert that adding polishing technology to amalgam separation will result in mercury
discharge reductions that have a discernible environmental impact greater than the reductions
achieved by amalgam separation alone. EPA estimates that the capital costs of amalgam
separators and polishing are at least 4 times that of amalgam separators alone (ERG, 2011).
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 the proposed rule.
8.1.1 Requirements
The proposed rule would establish a pretreatment standard that would require removal of
at least 99.0 percent of total mercury from amalgam discharges and require dental offices to
follow BMPs. Affected dental offices would be able to meet the standard by using, properly
operating, and maintaining a dental amalgam separator certified to achieve at least 99.0 percent
reduction of total mercury according to the 2008 ISO 11143 standard, to perform certain BMPs,
and to certify to this effect. Dental offices could also meet the standard by certifying that they do
not install or remove amalgam except in limited emergency circumstances. As a point of
clarification, dentists that elect to 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 who 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, relatively low cost technology. Dental offices that elect not to use
an amalgam separator must still 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 the 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.
The proposed rule would subject all dentists (except certain specialists as described in
Section 4.2) to categorical pretreatment requirements. EPA recognizes that some dentists
potentially subject to the 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 determine a publicly available source of information that would enable
identification of dental offices where dental amalgam may reasonably be expected not to be
present. As such, the 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
-------
Section 8 - Regulatory Options
will not install or remove amalgam (not including infrequent emergency treatment). This would
fulfill their obligations under the 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 the proposed rule.
EPA does not want to penalize existing dental offices or institutional dental facilities that
have already installed amalgam separators 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 lower than the proposed standard. For example, some
states require dental offices to employ amalgam separators that are certified to remove 95 percent
total mercury. EPA's proposed rule does not require existing separators with a remaining useful
life to be retrofitted with new separators. EPA chose to avoid imposing additional costs on dental
facilities that moved ahead of EPA's proposed requirements to install a treatment technology,
and also chose to avoid the additional solid waste that would be generated by disposal of
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
10 years from the effective date of the final rule. EPA selected 10 years because it appears to be
a conservative estimate of the useful life of the existing equipment. However, if a currently
installed separator needs to be replaced before 10 years have elapsed, these facilities would need
to install and operate an amalgam separator that meets the proposed removal efficiency of at
least 99.0 percent.
8.2 PRETREATMENT STANDARDS FOR NEW SOURCES (PSNS)
Under Section 307(c) of the CWA, new sources of pollutants into publicly owned
treatment works (POTWs) must comply with standards that 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 has
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 PSNS that are the same as
those proposed for existing sources (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. New sources would need to comply with the requirements discussed in
Section 8.1.1.
8-3
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Section 8 - Regulatory Options
8.3 REFERENCES
ERG (Eastern Research Group). 2011. Polishing System for Removing Dissolved Mercury
Review. Memorandum. Chantilly, VA. May 23. Document Control Number (DCN)
DA00122.
Garcia, A. 2009. EPA Audit Follow-Up Report. U.S. EPA Region 8. September 15. DCN
DA00164.
U.S. EPA. 2011. Economic Analysis for the Dental Amalgam Rule. MS Excel™ file. Office of
Water. Washington, DC. DCNDA00145.
8-4
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Section 9 - Costs of Technologies
SECTION 9
COSTS OF TECHNOLOGIES
This section provides information on EPA's approach for estimating compliance costs for
dental offices. EPA's cost methodology assumes dental offices would use the required best
management practices (BMPs) in combination with 2008 ISO 11143 amalgam separators on the
market today to comply (see Section 7.1.2). EPA categorized all of the costs as either capital
costs (one-time costs associated with planning or installation of technologies), as operations 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. Cost
estimates are expressed in terms of 2010 dollars.
9.1 METHODOLOGY FOR DEVELOPING MODEL DENTAL OFFICE COSTS
EPA estimated compliance costs associated with the proposed rule 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 the proposed rule. For costing purposes,
EPA differentiated dental offices by those that already use amalgam separators and those that do
not.
In general, one approach that EPA sometimes 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 substantial
facility-specific technical and financial data. In the case of the Dental Category, EPA would need
such data for approximately 110,000 dental offices estimated to be subject to this proposed 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 affected facilities, then calculate costs
for each model facility. EPA can then determine how many affected facilities each model facility
represents, thereby modeling the full universe of affected facilities.
EPA used the model approach to estimate the costs to affected dental offices of
complying with the proposed Dental Amalgam Rule. The model approach includes calculating
compliance costs for dental offices based on the number of chairs at the practice (i.e., by size
classes of dental offices). EPA developed compliance costs for six models based on the numbers
of chairs in an office. The ranges for each model are: 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. The
costs for large facilities is discussed separately in Section 10.
EPA developed two sets of costs for each model: one for dental offices that do not
currently operate an amalgam separator and one for dental offices with that treatment technology
in place.
9-1
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Section 9 - Costs of Technologies
9.1.1 Model Compliance Costs for Dental Offices Without Amalgam Separators
For offices that do not currently operate an amalgam separator, EPA estimated capital
costs and O&M costs. Capital costs include the purchase of the amalgam separator and
installation. Recurring costs include replacement of the cartridge and other O&M costs such as
maintenance supply costs; inspection costs; maintenance costs; recycling preparation; and
recycling costs.
The costs of amalgam separators varies, but is relative to the size (number of chairs) of
the dental practice. The number of amalgam separators required depends on the number of chairs
in an office and the amalgam separator model. Wastewater flow rate determines how often filters
and traps need to be cleaned/replaced (Walsh, 2007). Manufacturer suggested retail prices
(MSRP) for an amalgam separator range from $210 to $3,984 (depending on the size of the
dental office). Table 9-1 provides a summary of costs of commercially available amalgam
separator systems (non-inclusive), including specific O&M costs for each model (in 2010
dollars).
Installation costs will also vary depending on the existing configuration of the dental
office. Based on conversations with amalgam separator vendors, EPA estimated plumbing
modifications for initial installation would cost $250, regardless of the size of the office (ERG,
2010.
9-2
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Table 9-1. Cost of Purchasing, Operating, and Maintaining Amalgam Separators ($2010)
Model
A1250
AD-1000
Amalgam Boss
Amalgam Collector
— CE18
Amalgam Collector
— CE24
Amalgam Collector
— CH12
Amalgam Collector
— CH9
ARU-10
AsdexAS-10
Asdex AS-20
Asdex AS-20
Asdex AS-9
BU10
Manufacturer
Air Techniques
American Dental
Accessories
M.A.R.S. Bio-Med
Processes
R & D Services
R & D Services
R & D Services
R & D Services
Hygenitek
Capsule Technologies
Capsule Technologies
American Dental
Accessories
American Dental
Accessories
Dental Recycling
North America
MSRP
$1,000
$809
$1,015
$83 9-$ 1,220
$1,265-$1,647
$605-$986
$626-$ 1,020
$770-$803
$233
$332
$300
$210
$762
Maintenance
Replace filter every 6-12 months.
Replace filter every 18 months.
Unit switch out after 2 years for 1
chair, 1.5 years for 2-3 chairs and
1 year for 4-10 chairs.
Recycle every 3 years; adjust
liquid level tube every 6 months.
Recycle every 3 years; adjust
liquid level tube every 6 months.
Recycle every 4 years; adjust
liquid level tube every 6 months.
Recycle every 3 years; adjust
liquid level tube every 6 months.
Replace ion cartridge every 6
months, replace settlement tank
every 2 years.
Replace filter every 6-8 months.
Replace cartridge every 6-8
months.
Replace filter every 6-12 months.
Replace filter every 6 months.
Replace canister every 12
months.
Replacement
Parts
Filter: $250
Filter: $504
Separator unit:
$1,015
Not available
Not available
Not available
Not available
Cartridge, settling
tanks: $179
Filter: $99
Cartridge: $198
Filter: $177
Filter: $80
Canister: $508
Recycling
Not included in
MSRP
Not included in
MSRP
Included in MSRP
Recycling service:
$254
Recycling service:
$305
Recycling service:
$305
Recycling service:
$316
Included in MSRP
Not included in
MSRP
Not included in
MSRP
Not included in
MSRP
Not included in
MSRP
Included in MSRP
Reference
7
2
1,3
1
1
1
2,4
5,6
1
1
1,8
8
1,9
s
o
o
<3
O
U
o
-------
Table 9-1. Cost of Purchasing, Operating, and Maintaining Amalgam Separators ($2010)
Model
BU30
Catch 1000 Plus
Catch 400 Plus
Catch 9000 Plus
ECO II
Hg5
Hg5 High Volume
Hg5 Mini
Liberty Boss
Merc II
MRU10
MRU30
MSS 1000
Manufacturer
Dental Recycling
North America
Rebec Solutions
Rebec Solutions
Rebec Solutions
Pure Water
Development
SolmteX
SolmeteX
SolmeteX
M.A.R.S. Bio-Med
Processes
Bio-Sym Medical
Dental Recycling
North America
Dental Recycling
North America
Maximum Separation
Systems
MSRP
$1,418
$2,042
$1,204
$3,984
$570
$762
$2,500
$762
$1,574
$1,300
$1,250
$1,795
$1,288
Maintenance
Replace canister every 12
months.
Replace canister every 12
months.
Replace canister every 12
months.
Replace canister every 12
months.
Replace canister every 12
months.
Replace cartridge every 6-12
months.
Replace cartridge every 12
months.
Replace cartridge every 6-12
months.
Unit switch out after 3 years for
1-3 chairs, 2 years for 4-10
chairs, 1 year for 11-17 chairs.
Replace cartridge every 12
months.
Replace canister every 12
months.
Replace canister every 12
months.
Replace settling tank every 12
months.
Replacement
Parts
Canister: $762
Canister: $656
(price is for 2
canisters)
Canister: $656
(price is for 2
canisters)
Canister: $910
(price is for 3
canisters)
Canister: $209
Cartridge: $304
Cartridge: $170-
$285
Cartridge: $304
Separator unit:
$1,574
Cartridge: $495
Canister: $1,195
Canister: $1,395
Settling tank:
$178
Recycling
Included in MSRP
Included in MSRP
Included in MSRP
Included in MSRP
Not included in
MSRP
Included in MSRP
Not included in
MSRP
Included in MSRP
Included in MSRP
Included in MSRP
Included in MSRP
Included in MSRP
Not included in
MSRP
Reference
1,9
1, 10
1, 10
1, 10
1
1, 11
1, 11
1, 11
1
5
2,9
9
2,3
s
o
o
<3
O
U
o
-------
Table 9-1. Cost of Purchasing, Operating, and Maintaining Amalgam Separators ($2010)
Model
MSS 2000
MSS 601
Rasch 890-1000
Rasch 890- 1500
Rasch 890-4000
Rasch 890-6000
Rasch 890-7000
Rasch AD-1500
REM2000
Series/Catch 1000
REM2000
Series/Catch 400
REM2000
Series/Catch 9000
Manufacturer
Maximum Separation
Systems
Maximum Separation
Systems
AB Dental Trends
AB Dental Trends
AB Dental Trends
AB Dental Trends
AB Dental Trends
American Dental
Accessories
Rebec Solutions
Rebec Solutions
Rebec Solutions
Average Cost for 1 to 2 Chairs
Average Cost for 3 to 5 Chairs
Average Cost for 6 Chairs
Average Cost for 7+ Chairs
MSRP
$1,418
$1,167
$1,251
$731
$1,352-$1,931
$700
$1,132
$675
$2,028
$1,204
$3,984
$408-$596
$552-$645
$1,055-$1,060
$1,509-$1,552
Maintenance
Replace settling tank every 12-18
months.
Replace settling tank every 12
months.
Replace canister every 12-18
months
Replace canister every 12-18
months
Replace canister every 18 months
Replace canister every 12-18
months
Replace canister every 12-18
months.
Replace filter every 18 months.
Replace cartridge every 12
months.
Replace cartridge every 12
months.
Replace cartridge every 12
months.
Replacement
Parts
Settling tank:
$168
Settling tank:
$178
Canister: $627
Canister: $627
Canister: $660-
$1,319
Canister: $628
Canister: $627
Filter: $470
Cartridge: $452
Cartridge: $452
Cartridge: $808
$195
$231
$430
$629-$664
Recycling
Not included in
MSRP
Not included in
MSRP
Included in MSRP
Included in MSRP
Included in MSRP
Included in MSRP
Included in MSRP
Included in MSRP
Included in MSRP
Included in MSRP
Included in MSRP
Reference
2
3
2,4
1,4
2
1,4
1,4
1,8
1, 10
1, 10
2, 10
s
o
o
<3
O
U
o
Sources: (1) - U.S. Air Force, 2011; (2) - MCES, 2009; (3) - MMSD and University of Wisconsin-Extension, 2006; (4) - ADA, 2007; (5) - McManus and
Fan, 2003; (6) - SF Environment, 2005; (7) - ERG and Air Techniques, 2011; (8) - ERG and American Dental Accessories, 2011; (9) - ERG and DRNA,
2011; (10) - ERG and Rebec Solutions, 2011; (11) - ERG and SolmeteX, 201 Ib.
-------
Section 9- Costs of Technologies
Table 9-2 provides a summary of the one-time model facility costs for dental offices that
do not currently use amalgam separators. The separator purchase cost for the various chair sizes
in the average of the range provided in Table 9-1.
Table 9-2. Summary of One Time Costs ($2010) to
Model Dental Offices Without Amalgam Separators
Cost Element
Separator Purchase
Installation
Number of chairs in the model dental office
lor 2
$502
$250
3,4,or5a
$599
$250
6
$1,058
$250
7+
$1,531
$250
Sources: See Table 9-1; ERG, 2010
a - 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.
EPA also estimated annual costs which include O&M costs and separator replacement
costs. Operation and maintenance costs include the following:
• Inspection and maintenance: The proposal would require that the separator be
inspected at least monthly. EPA included costs for a dental assistant ($17/hr18) to
perform a five minute visual inspection monthly for all dental office sizes. The
proposed rule would also require the separator to be maintained regularly. For all
dental office sizes, EPA assumed maintenance would be performed by a dental
assistant every two weeks and that each maintenance session would take 15 minutes.
• Recycling preparation: Most separators require that their solids collectors and/or
filters be replaced at least every 12 months. EPA assumed that a dental assistant
($17/hr) would spend 15 minutes two times per year preparing materials for shipping
and recycling for all dental office sizes.
• Recycling service costs: The range of recycling service costs provided by vendors is
$0 (some include recycling costs as part of the original purchase cost) to $316 per
recycling event (see Table 9-1). Assuming a conservative estimate of recycling every
two years, the maximum annual cost for recycling service is $158 per year. EPA
estimated recycling costs as the average of the range ($0 to $158), or $79 per year, for
all dental office sizes (ERG, 2014).
For separator replacement costs, EPA estimated that amalgam separators would have a
service life often years, after which time the amalgam separator would need to be replaced. See
Section 10.2.1.
Table 9-3 provides a summary of annual model facility costs for dental offices that do not
currently use amalgam separators.
18 Bureau of Labor Statistics reported a wage of $16.41 per hour for this job category in May 2011 (Bureau of Labor
Statistics, 2011). EPA rounded up to $17 per hour.
-------
Section 9- Costs of Technologies
Table 9-3. Summary of Annual Costs ($2010) to Model Dental Offices
Without an Amalgam Separator
Cost Element
Replacement Parts
O & M including recycling
Number of chairs in the model dental office
lor 2
$195
$216
3, 4, or 5a
$219
$216
6
$430
$216
7+
$647
$216
Sources: See Table 9-1; U.S. EPA, 20lib.
a 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 office sizes.
9.1.2 Model Compliance Costs for Dental Offices Currently Using Amalgam Separators
EPA also differentiated costs at the office level based on whether offices already have
amalgam separators in place. EPA assumed that offices with treatment in place will incur no cost
for purchasing and installing compliance technology at the time of initial regulatory compliance.
However, EPA estimated additional permit-related costs (see Section 10.2) and some recurring
incremental costs for such offices. Specifically, EPA assumed that dental offices with
technology-in-place would incur recurring costs in relation to the costs otherwise incurred by
offices without technology-in-place, as shown in Table 9-4 and Table 9-5.
Table 9-4. Percentage of Recurring Costs Incurred by Dental Offices Currently Using
Amalgam Separators
Cost Category
Replacement parts
Amalgam separator maintenance
Amalgam separator operation
Recycling preparation and recycling service cost
Percentage of Costs Incurred"
50 percent
50 percent
100 percent
50 percent
a The percentage of costs estimated to be incurred by offices with technology-in-place relative to costs estimated to
be incurred by office without technology-in-place.
Source: U.S. EPA, 201 Ib.
Table 9-5. Summary of Annual Model Facility Costs ($2010) to Dental Offices Currently
Using Amalgam Separators
Cost Element
Replacement Parts
O & M including recycling
Number of chairs in the model dental office
lor 2
$98
$116
3, 4, or5a
$110
$116
6
$215
$116
7+
$324
$116
aEPA 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 office sizes.
9.2 REPORTING REQUIREMENTS AND BMP COSTS
All dental offices subject to the proposed Dental Amalgam Rule will have reporting
requirements and BMP requirements. EPA included reporting costs for one-time preparation of a
9-7
-------
Section 9- Costs of Technologies
baseline report and initial compliance report19 and recurring costs associated with preparation of
an annual certification statement. EPA estimates that an office or dental assistant would require
the following times to complete each report:
• 76 minutes to complete the baseline monitoring report;
• 51 minutes to complete the initial compliance report; and
• 49 minutes to complete the annual certification statement.
As has been mentioned, EPA recognizes that some dental offices subject to the proposed
rule do not place or remove amalgam and has proposed a provision that allows non-users of
amalgam to submit a one-time baseline monitoring report to certify that they do not use amalgam
except in unusual emergency circumstances. Should the status of a non-using 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 CFR
441.10.
Assuming a labor rate of $17 per hour for a dental assistant (based on Bureau of Labor
Statistics for May 2011), EPA estimates that the cost to complete the baseline monitoring report
is $22, the cost to complete the initial compliance report is $15, and the cost to complete the
annual certification is $14 (U.S. EPA, 201 la).
EPA did not include incremental costs for 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.
9.3 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. EPA estimated that these
facilities would incur compliance technology costs in the same categories as other facilities, with
compliance equipment costs being 50 percent greater than those incurred by facilities in the 7+
chairs category. All other costs are the same as those incurred by facilities in the 7+ chairs
category (U.S. EPA, 201 Ib). These costs are likely overstated as they do not reflect opportunities
the largest offices may have to share costs,20 and they do not assume any economies of scale.
Section 10 provides further details on costs developed for larger dental facilities.
9.4 REFERENCES
ADA (American Dental Association). 2007. ADA Professional Product Review. Document
Control Number (DCN) DA00043.
19 These are required under 40 CFR 403.
20 For example, multiple dental offices located in the same 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 system.
-------
Section 9- Costs of Technologies
Bureau of Labor Statistics. 2011. May 2011 National Occupational Employment and Wage
Estimates. May. DCN DA00250.
ERG (Eastern Research Group). 2010. SolmeteX meeting minutes for 15 December 2010.
Chantilly, VA. DCNDA00081.
ERG. 2014. Pollution Prevention Program Costs for Controlling Dental Amalgam Discharges.
Memorandum. September 22. Chantilly, VA. DCN DA00249.
ERG and Air Techniques. 2011. Notes from telephone conversation between Kimberly Landick,
ERG, and Air Techniques, March 2, 2011: Subject Amalgam Separator Questions. DCN
DA00060.
ERG and American Dental Accessories. 2011. Email correspondence between Kimberly
Landick, ERG, and American Dental Accessories, February 28, 2011: Subject Request
for Amalgam Separator Information. DCN DA00061.
ERG and DRNA. 2011. Notes from telephone conversation between Kimberly Landick, ERG,
and Marc Sussman and Darwin Moreira, DRNA, March 1, 2011: Subject Amalgam
Separator Questions. DCN DA00062.
ERG and Rebec Solutions. 2011. Notes from telephone conversation between Kimberly Landick,
ERG and Rebec Solutions, March 2, 2011: Subject Amalgam Separator Questions. DCN
DA00063.
ERG and SolmeteX. 201 Ib. Notes from telephone conversation between Kimberly Landick,
ERG and SolmeteX, March 2, 2011: Subject Amalgam Separator Questions. DCN
DA00064.
MCES (Metropolitan Council Environmental Services). 2009. Revised - Features of Approved
Amalgam Separators. March. DCN DA00070.
McManus, K.R., and P.L. Fan. 2003. Purchasing, Installing and Operating Dental Amalgam
Separators. Journal of the American Dental Association 134:1054-1065. DCNDA00162.
MMSD and University of Wisconsin Extension. 2006. Amalgam Management for Dental
Offices. http://www4.uwm.edU//shwec/publications/cabinet/pdf/DentalAmalgam2.pdf
DCN DA00232.
SF Environment. 2005. San Francisco Department of the Environment. San Francisco City and
County List of Approved Amalgam Separators. March. DCN DA00077.
U.S. Air Force. 2011. Synopsis of Dental Amalgam Separators. January 24. Dental Evaluation
and Consultation Service. DCN DA00079.
U.S. EPA. 201 la. EPA Analysis: Part 441 Option Cost Calculations. MS Excel™ file. Office of
Water. Washington, DC. DCNDA00146.
U.S. EPA. 201 Ib. Economic Analysis for the Dental Amalgam Rule. MS Excel™ file. Office of
Water. Washington, DC. DCNDA00145.
-------
Section 9- Costs of Technologies
Walsh, William. 2007. The American Dental Association's (ADA) Comments on EPA's Study
of a Pretreatment Requirement for Dental Amalgam. Pepper Hamilton, LLP. December
21.DCNDA00238.
9-10
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Section 10 - Economic Impacts for the Dental Industry
SECTION 10
ECONOMIC IMPACTS FOR THE DENTAL INDUSTRY
This section describes EPA's economic impact assessment of the proposed Dental
Amalgam Rule, and is organized as follows:
• Section 10.1 reviews the structure of the regulated sector in terms of number of dental
offices potentially subject to the proposed Dental Amalgam Rule and the distribution
of these offices by revenue.
• Section 10.2 presents the compliance costs that EPA expects would be incurred by
dental offices under the proposed rule.
• Section 10.3 combines the estimates of numbers of in-scope offices by relevant
operating characteristics to estimate total nationwide compliance costs for the
proposed rule.
• Section 10.4 assesses the social cost of the proposed Dental Amalgam Rule, including
costs to dental offices (and facilities)21 and the costs to permitting authorities for
administering rule requirements.
• Section 10.5 determines the potential for significant economic impact on small dental
office entities as a result of the proposed rule.
10.1 OVERVIEW OF DENTAL OFFICES POTENTIALLY SUBJECT TO PROPOSED REGULATION
In this section, EPA reviews its estimate of the number of dental offices that might be
within the scope of the proposed rule, including:
• A review of information from the Economic Census and other sources on the number
of offices in the dental sector.
• Adjustments to these counts to reflect baseline levels of (1) number of dental facilities
using mercury-containing materials (dental amalgam); (2) the number of dental
facilities that currently use treatment technology; and (3) as a result, the costs likely
to be incurred by dental offices in complying with the proposed rule.
10.1.1 Number of Dental Offices Potentially Subject to the Proposed Regulation
To support the assessment of total costs and economic impact of the proposed Dental
Amalgam Rule, EPA relied on data from the 2007 Economic Census describing the number of
firms and establishments in the dental office sector (NAICS 621210), and their annual receipts
(revenue). EPA used the 2007 Census data for this analysis because these data are the most
recent comprehensive public data on the dental office sector. Data on the number of dental office
21 As explained in Section 2, dental offices include but are not limited to institutions, permanent or temporary
offices, clinics, mobile units, home offices, and facilities, including dental facilities owned and operated by Federal,
state or local governments.
KM
-------
Section 10 - Economic Impacts for the Dental Industry
firms and establishments by revenue size are used to assess the number of regulated entities that
may incur costs, the costs that these entities may incur (based on their scale of business
operations and associated need for compliance technology), and thus the rule's total cost. These
data are also used to assess the potential impact of a regulation in terms of the level of costs that
may be incurred by individual firms/establishments and whether these costs would be unduly
burdensome in relation to their ongoing revenue.
EPA determined that the operating characteristics of the individual dental offices — in
particular, the number of dental chairs in the office — would be a key determinant of the
technology response and associated compliance costs that would be incurred by dental offices in
complying with the proposed Dental Amalgam Rule. Therefore, EPA estimated compliance costs
for each dental office size. In addition, in reviewing the 2007 Economic Census data for the
dental office sector, EPA observed that almost all firms are single-establishment/single-office
firms. The total of 127,057 establishments/offices is owned by 121,048 firms — thus no more
than 6,009 firms, or fewer than 5 percent of firms, can be multi-office firms. And only at the
highest revenue ranges do firms frequently own and operate more than one office. Thus, as a
practical matter, there is little difference between the number of dental offices and the number of
dental firms. For this reason, EPA performed the impact analysis at the level of the office instead
of the level of the firm.
Starting with the 2007 Economic Census counts of dental offices, EPA applied a number
of adjustments to estimate the number of dental offices, in aggregate and by revenue range, that
could be within the scope of the proposed Dental Amalgam Rule:
• As shown in Table 10-1, the Economic Census listed 127,057 dental offices in total.
In addition, office counts are spread over 11 revenue ranges, ranging from the lowest
range, $0-$ 10,000, to the highest range, $10,000,000 and up, based on 2007 dollars.
EPA performed its cost and economic impact analysis based on 2010 dollar values.
Because the Economic Census revenue ranges are defined in 2007 dollars, EPA
adjusted these dollar values defining the revenue ranges to 2010 dollars using the
GDP Deflator, a sector-/commodity-neutral basis for adjusting dollar values for
general inflation over time. Table 10-1 lists the revenue range values in 2007 and
2010 dollars in the left set of columns of the table. This adjustment assumes that
dental service prices matched the general rate of inflation over the 2007-2010 period,
and that the industry remained constant in all other regards: total quantity of services
provided and total number and distribution of offices by revenue range.
• Of the 127,057 total offices, the Economic Census reported 116,792 offices as being
in business for the full 2007 year and 10,265 offices as being in business for only part
of the year. The numbers of dental offices listed in the 11 revenue ranges represent
the 116,792 offices that were in business for the full 2007 year. Because the revenue
range of offices is important in estimating the compliance requirements that an
individual office would face, and also for assessing small entity impacts, EPA
assigned the remaining 10,265 offices (those in business for only part of the year)
across the revenue ranges of offices that were in business for the full year, in the same
proportion as the full year offices. EPA assigned these partial-year offices to the small
business revenue ranges (the first nine ranges) to prevent potentially understating the
number of small businesses that could incur costs as a result of the proposed Dental
-------
Section 10 - Economic Impacts for the Dental Industry
Amalgam Rule. The tenth revenue range includes the Small Business Administration
revenue cutoff ($7.0 million), and EPA assigned none of the partial-year offices to
this range.22 The right-most column in Table 10-1 reports the numbers of offices by
revenue range after this adjustment.
Table 10-1. Dental Office Establishments by
Revenue Range (NAICS 621210, Offices of Dentists)
Revenue Ranges ($2007)
Low
0
$10,000
$25,000
$50,000
$100,000
$250,000
$500,000
$1,000,000
$2,500,000
$5,000,000b
$10,000,000
High
$10,000
$24,999
$49,999
$99,999
$249,999
$499,999
$999,999
$2,499,999
$4,999,999
$9,999,999
Or more
Revenue Ranges ($2010)
Low
0
$10,449
$26,121
$52,243
$104,486
$261,214
$522,428
$1,044,857
$2,612,142
$5,224,284
$10,448,568
High
$10,448
$26,120
$52,242
$104,485
$261,213
$522,427
$1,044,856
$2,612,141
$5,224,283
$10,448,567
Or more
Establishments operated for the entire year
Establishments not operated for the entire year
Total Establishments
Number
Establishments
160
471
940
2,401
13,034
28,766
42,803
25,046
2,783
330
58
116,792
10,265
127,057
Adjusted Number
Establishments"
174
513
1,023
2,613
14,183
31,303
46,578
27,255
3,028
330
58
127,057
-
127,057
Sources: Census, 2007; U.S. EPA, 201 Ic.
a — With establishments not operating for the entire year assigned to first nine revenue ranges.
b — Highlighting in the $5 million to $10 million revenue range indicates that this range contains the SBA small
business size standard for offices of dentists.
In addition to the dental offices that are reported in the Economic Census, EPA estimates
that dental services potentially within the scope of this regulation are performed at an additional
130 large institutional dental facilities (e.g., clinics or dental schools, see Section 4.1). Adding
these 130 facilities to the 127,057 dental offices from the Economic Census brings the total of
dental offices and facilities that are potentially within the rule's scope to 127,187.
10.1.2 Adjustments to Account for Baseline Status
EPA also accounted for additional factors that will influence the extent to which dental
office sector would incur costs under the proposed Dental Amalgam Rule:
• First, EPA recognized that certain specialty dental practices do not place or remove
dental amalgam (see Section 4.2) and thus did not include them in the scope of the
proposed rule. These specialty practices are: oral pathology, oral and maxillofacial
radiology, oral and maxillofacial surgery, orthodontics, periodontics, and
prosthodontics. Based on information from the American Dental Association (ADA),
EPA estimated that 21 percent of total dental offices are specialty service practices.
Within this group of specialty practices, approximately 65 percent do not place or
remove dental amalgam (ADA, 2010a; Vandeven and McGinnis, 2005). As a result,
of the total of dental offices, EPA estimated that approximately 14 percent are
22 See discussion in Section 10.5 for information on the assessment of small entity impacts.
-------
Section 10 - Economic Impacts for the Dental Industry
specialists that would not be subject to the proposed rule.23 Because the proposed rule
would not apply to them, EPA assigned no compliance-related costs to these 17,215
offices, and these offices are not included in the impacts analysis (U.S. EPA, 201 Ic).
• Second, EPA divided the in-scope offices into two groups: (1) offices that have
already installed amalgam separators and (2) offices without amalgam separators.
Offices with amalgam separators already in place will incur lower costs relative to
offices without treatment technology in place. From a review of state requirements,
EPA estimates that 40 percent of offices have amalgam separators in place already,
and used this percentage to categorize offices as technology-in-place offices and no-
technology-in-place offices (U.S. EPA, 201 la).
• Third, among the remaining 60 percent of offices that have not already installed
amalgam separators, EPA estimated that approximately 20 percent of these dental
offices do not place or remove dental amalgam (Pimpare, 2012) and thus would incur
no treatment technology-related costs due to the proposed Dental Amalgam Rule.
These offices would need to certify to their permitting authority that they do not
process amalgam, for which the offices would incur a one-time only reporting cost.
Table 10-2 lists the numbers of dental offices by revenue range (from Table 10-1), and
including large facilities, with these further breakouts. EPA carried these estimated numbers of
dental offices and large facilities by baseline amalgam use and compliance status forward to the
cost and economic impact analysis.
23 0.21 x 0.65 ~ 0.135. See U.S. EPA, 201 la, for further information on this estimate.
KM
-------
Table 10-2. Adjusting Office Counts to Account for Baseline Amalgam Use and Technology in Place
Revenue Ranges ($2010)
(see Table 10-1)
Low
0
$10,449
$26,121
$52,243
$104,486
$261,214
$522,428
$1,044,857
$2,612,142
$5,224,284
$10,448,568
High
$10,448
$26,120
$52,242
$104,485
$261,213
$522,427
$1,044,856
$2,612,141
$5,224,283
$10,448,567
Or more
Total Economic Census
Institutional Facilities
Total
Number of Offices
Total
(see Table 10-1)
174
513
1,023
2,613
14,183
31,303
46,578
27,255
3,028
330
58
127,057
130
127,187
Percentage adjustment factors
Not Using
Amalgam
24
69
138
354
1,920
4,237
6,304
3,689
410
45
8
17,198
18
17,215
13.5%
Using
Amalgam
151
443
884
2,259
12,264
27,066
40,273
23,566
2,619
285
50
109,859
112
109,972
86.5%
Technology-In-
Place
61
179
358
913
4,958
10,943
16,282
9,528
1,059
115
20
44,416
45
44,462
40.4%
No-Technology-In-Place
Total
90
264
527
1,346
7,305
16,123
23,991
14,038
1,560
170
30
65,443
67
65,510
59.6%
With Technology
Costs
72
211
421
1,077
5,844
12,898
19,193
11,230
1,248
136
24
52,355
54
52,408
80.0%
No Technology
Costs
18
53
105
269
1,461
3,225
4,798
2,808
312
34
6
13,089
13
13,102
20.0%
Sources: Census, 2007 and U.S. EPA, 201 Ic.
in
ft
o
o'
o'
I
ft
a
I
-------
Section 10 - Economic Impacts for the Dental Industry
10.2 SUMMARY OF THE PROPOSED REGULATION AND COMPLIANCE COSTS
EPA developed national cost estimates for dental offices to purchase and install amalgam
separators, maintain the separators (combination of annual part/supply costs and labor costs),
recycle the dental amalgam waste, and comply with inspection and reporting requirements. EPA
prepared the costs to the industry of implementing the rule, taking into account any dental
amalgam control practices that are currently mandated by state and local pretreatment programs.
EPA assumed there would be no increased costs to dental offices to implement the two best
management practices (BMPs) in the proposed rule.
10.2.1 Summary of Compliance Costs
Using the methodology described in Section 9, EPA developed compliance costs for
model facilities with and without amalgam separators. As described in Section 9, EPA assumed
that offices with treatment-in-place would incur no cost for purchasing and installing compliance
technology at the time of initial regulatory compliance. However, EPA estimated additional
permit-related costs and some recurring incremental costs (i.e., annual and one-time costs) for
such offices.
EPA developed compliance costs based on the number of dental chairs in an office, as
discussed in Section 9.1. The number of operatory chairs is the key driver of cost because the
treatment capacity, and thus cost, of amalgam separators is based on the number of chairs
serviced by the separator. Accordingly, EPA estimated costs for these cost categories based on
the numbers of chairs in an office, organized within six number-of-chair ranges, as follows:
• 1 to 2 chairs; • 4 chairs; • 6 chairs; and
• 3 chairs; • 5 chairs; • 7+ chairs.
EPA also estimated costs for the large institutional facilities (such as clinics or
universities). For purposes of costs, EPA assumed the average institutional facility has 15 chairs.
See Section 9.3 for more details.
Table 10-3 lists estimated compliance costs for offices that have and have not already
installed amalgam separators, in 2010 dollars, by cost category and by size (i.e., number of
chairs). A size category for large facilities (which average 15 chairs) is also included.
10-6
-------
Table 10-3. Dental Office Compliance Costs by Cost Category and Number of Chairs (2010 dollars)
Cost Element
No-Technology-In-Place
Operating Size: Number of Chairs and Large Facilities
1-2
3
4
5
6
7+
Large
Fac.
Technology-In-Place
Operating Size: Number of Chairs and Large Facilities
1-2
3
4
5
6
7+
Large
Fac.
Technology Installation and Other Startup Costs
Equipment
purchase
Installation
One-time baseline
monitoring report
(BMR)
One-time
compliance report
$502
$250
$22
$15
$599
$250
$22
$15
$599
$250
$22
$15
$599
$250
$22
$15
$1,058
$250
$22
$15
$1,531
$250
$22
$15
$2,297
$250
$22
$15
$0
$0
$22
$15
$0
$0
$22
$15
$0
$0
$22
$15
$0
$0
$22
$15
$0
$0
$22
$15
$0
$0
$22
$15
$0
$0
$22
$15
Annual Costs
Replacement parts
Separator
maintenance
Recycling
preparation
Recycling service
Visual Inspection
Annual
certification
$195
$111
$9
$79
$17
$14
$219
$111
$9
$79
$17
$14
$219
$111
$9
$79
$17
$14
$219
$111
$9
$79
$17
$14
$430
$111
$9
$79
$17
$14
$647
$111
$9
$79
$17
$14
$647
$111
$9
$79
$17
$14
$98
$55
$4
$40
$17
$14
$110
$55
$4
$40
$17
$14
$110
$55
$4
$40
$17
$14
$110
$55
$4
$40
$17
$14
$215
$55
$4
$40
$17
$14
$324
$55
$4
$40
$17
$14
$324
$55
$4
$40
$17
$14
in
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Source: U.S. EPA, 201 Ic.
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Section 10 - Economic Impacts for the Dental Industry
In assessing the costs of compliance, EPA estimated that amalgam separator equipment
would have a service life of 10 years, after which time the compliance equipment would need to
be replaced. For the estimation of reinstallation costs, EPA assumed that offices, regardless of
original technology-in-place status, would incur the full cost of purchasing compliance
equipment at the time of technology reinstallation. However, because various modifications
needed for equipment installation would have been completed during initial installation, EPA
estimated, for reinstallation, that compliance equipment would be able to be installed at one-half
the cost of the original installation. Further, EPA assumed that dental offices would incur
ongoing expenses in the same way as described in the preceding paragraphs and Table 10-3.
To summarize, EPA accounted for the initial installation and re-installation requirement
by building up costs, as described, for two separate analysis periods:
1. Years 1-10.24 In this period, dental offices that place or remove amalgam and have
no-technology-in-place are assumed to install compliance equipment, if needed, and
incur other startup costs at the beginning of year 1. Recurring costs are then incurred,
as described above, in years 1-10.
2. Years 11-20. In this period, all dental offices that place or remove amalgam are
assumed to incur the cost of reinstalling compliance equipment at the beginning of
year 11. Recurring costs then incurred, as described, in years 11-20.
For the assessment of compliance costs to dental offices, EPA accumulated these costs on
a present value basis at year 1 at a discount rate of seven percent, which is intended to represent
the opportunity cost of capital to society, on a pre-tax, constant dollar basis.25 The resulting
present value is then annualized over the full 20-year analysis period at the seven percent interest
rate. EPA used the resulting total annualized compliance costs in assessing the total estimated
cost and impact of the proposed rule to dental offices, as described in subsequent sections. Table
10-3 and Table 10-4 report specific elements of compliance costs and summarize the tabulation
of costs to develop estimates of the total annualized compliance cost to dental offices.
Table 10-4, below, summarizes the tallying of these costs according to the initial
installation and reinstallation specifications, and present value and annualized cost calculations,
as described above. For each installation event, the table reports the total initial outlay and
annually recurring costs, as incurred, and then summarizes the tabulation of these costs on a
present value basis. Initial technology installation costs are directly tabulated at the beginning of
year 1 (the year of initial compliance), while reinstallation costs are first tabulated on a present
value basis at the beginning of year 11, and then further discounted to the beginning of year 1.
Both present values are then summed and annualized over 20 years at a seven percent discount
rate. The resulting annualized costs include all of the cost elements except for operational and
annual certification costs, which are tallied in the final part of the table. Because these costs are
incurred annually and do not vary by technology-in-place status, they are simply added to the
annualized cost values in Table 10-4 to calculate the total annualized costs to dental offices and
large facilities for the proposed rule.
24 Where year 1 would be the first year in which a facility complies with the rule.
25 For the assessment of the rule's social costs, EPA used an additional discount rate of 3 percent and also applied a
different discounting treatment (see Section 10.4).
-------
Table 10-4. Summary of Annualized Compliance Costs for a Dental Office or Large Facility, Accounting
for Initial Installation and Reinstallation of Amalgam Separators, and Operational and Certification Costs
Cost Element
No-Technology-In-Place
Operating Size: Number of Chairs and Large Facilities
1-2
3
4
5
6
7+
Large
Fac.
Technology-In-Place
Operating Size: Number of Chairs and Large Facilities
1-2
3
4
5
6
7+
Large
Fac.
Initial Installation Analysis
Total initial outlay
Total annual (recurring) costs
Present value total annual
(recurring)
Total present value, at year 1
$789
$393
$2,760
$3,549
$886
$417
$2,929
$3,815
$886
$417
$2,929
$3,815
$886
$417
$2,929
$3,815
$1,345
$628
$4,411
$5,756
$1,818
$845
$5,935
$7,753
$2,584
$845
$5,935
$8,519
$37
$197
$1,380
$1,417
$37
$209
$1,464
$1,502
$37
$209
$1,464
$1,502
$37
$209
$1,464
$1,502
$37
$314
$2,205
$2,243
$37
$423
$2,967
$3,005
$37
$423
$2,967
$3,005
Reinstallation Analysis — Equipment Reinstalled at Beginning of Year 11
Total initial outlay (0.5
installation charge)
Total annual (recurring) costs
Present value total annual
(recurring)
Total present value, at year 1 1
Total present value, at year 1
$664
$393
$2,760
$3,424
$1,741
$761
$417
$2,929
$3,690
$1,876
$761
$417
$2,929
$3,690
$1,876
$761
$417
$2,929
$3,690
$1,876
$1,220
$628
$4,411
$5,631
$2,862
$1,693
$845
$5,935
$7,628
$3,878
$2,459
$845
$5,935
$8,394
$4,267
$664
$197
$1,380
$2,044
$1,039
$761
$209
$1,464
$2,226
$1,131
$761
$209
$1,464
$2,226
$1,131
$761
$209
$1,464
$2,226
$1,131
$1,220
$314
$2,205
$3,426
$1,741
$1,693
$423
$2,967
$4,661
$2,369
$2,459
$423
$2,967
$5,426
$2,758
Combining Initial Installation and Re-Installation
Sum, present values at year 1
Annualized cost over 20 years
$5,290
$499
$5,691
$537
$5,691
$537
$5,691
$537
$8,618
$814
$11,631
$1,098
$12,785
$1,207
$2,456
$232
$2,633
$249
$2,633
$249
$2,633
$249
$3,984
$376
$5,374
$507
$5,763
$544
Including Operational and Certification
Visual Inspection
Annual certification
Total Annualized Cost
$17
$14
$531
$17
$14
$569
$17
$14
$569
$17
$14
$569
$17
$14
$845
$17
$14
$1,129
$17
$14
$1,238
$17
$14
$263
$17
$14
$280
$17
$14
$280
$17
$14
$280
$17
$14
$408
$17
$14
$539
$17
$14
$575
Present values and annualized costs are calculated using a 7 percent discount rate. All costs are on a pre-tax basis, in 2010 dollars, and as of the time of compliance by
complying entities. The social cost analysis uses an additional 3 percent discount rate and applies a different discounting treatment.
Source: U.S. EPA, 201 Ic.
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Section 10 - Economic Impacts for the Dental Industry
As discussed in Section 10.1.2, EPA anticipates that some dental offices that do not
already have an amalgam separator do not place or remove dental amalgam, and thus would
incur no treatment technology-related costs from the proposed Dental Amalgam Rule. Although
these offices will not incur treatment technology-related compliance costs, they will incur the
cost of the one-time baseline monitoring report to document that they do not use amalgam in
their operations. EPA estimates this cost to be $22 for each of these offices/facilities. In
calculating the total compliance cost for the proposed rule, this value is annualized using the
discount rate and number of periods for non-recurring outlays, and added to the total rule costs
for offices and facilities incurring technology-related costs based on the estimated number of
offices not using dental amalgam.
10.2.2 Linking Compliance Costs By Number of Chairs to Dental Offices by Revenue
Range
The final step in developing compliance costs for use in the cost and economic impact
analysis is to link compliance costs by number of chairs to dental offices by revenue range. As
described in Section 10.1.1, the Economic Census reports information on dental offices by
revenue ranges. However, EPA determined that number of chairs is the key driver of technology
requirements, and thus estimated compliance requirements and costs based on the number of
chairs in the office. As a result, for estimating the compliance costs incurred by dental offices by
revenue range, it is essential to link offices by number of chairs to offices by revenue range. This
information is then used to estimate the total cost of regulatory compliance across dental
offices— based on numbers of offices by revenue range— and to estimate the impact of rule
requirements on dental offices, based on office revenue. Ideally, this linkage would have been
developed using a distribution of the number of chairs by dental office revenue range; however,
EPA was not able to obtain such data. As an alternative approach, EPA identified two sources of
data describing the distribution of number of chairs over all dental offices, regardless of office
revenue.
• "An Economic Study of Expanded Duties of Dental Auxiliaries in Colorado" (ADA,
2009). This study is called the "ADA Colorado Study" below. Based on a survey of
154 dental offices in Colorado, it provides a distribution of number of chairs by
office.
• "2009 Survey of Dental Practice: Income from the Private Practice of Dentistry"
(ADA, 2010b). This study, called the "ADA National Study" below, indirectly
reports a distribution of number of chairs by office.
Table 10-5 summarizes the number-of-chair distributions from these sources. Although
these sources do not use the same number-of-chair ranges, the summary distributions are
relatively similar. For example, the ADA National Study's data distribution indicates that 56
percent of offices have four or fewer chairs and the ADA Colorado Study indicates 64 percent of
offices with four or fewer chairs.
Table 10-5. Distribution of the Number of Chairs in Dental Offices
Number of Chairs in Office
Frequency
Relative Frequency
Running Total, Frequency
ADA Colorado Study, 2009
1-2
3
15
39
9.7%
25.3%
9.7%
35.1%
10-10
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Section 10 - Economic Impacts for the Dental Industry
Table 10-5. Distribution of the Number of Chairs in Dental Offices
Number of Chairs in Office
4
5
6
7 or more
Frequency
45
22
9
24
Relative Frequency
29.2%
14.3%
5.8%
15.6%
Running Total, Frequency
64.3%
78.6%
84.4%
100.0%
ADA National Study, 2010
1-2
3-4
5-6
7 or more
89
310
191
124
12.5%
43.4%
26.8%
17.4%
12.5%
55.9%
82.6%
100.0%
Sources: ADA, 2009, 2010b.
EPA used these distributions to estimate the number of chairs in offices that process
dental amalgam by revenue range. This estimation started with the assumption that increasing the
number of chairs in a dental office consistently increases office revenue.26 Beginning with the
lowest number-of-chairs range, one to two chairs, EPA assigned these offices to the lowest and
then successively higher revenue ranges until the entire percentage of offices with one or two
chairs was "used up." When the offices with a given number of chairs were "used up" without
exhausting a specific revenue range, the available percentage of offices with that number of
chairs was assigned within the revenue range assuming that offices are distributed uniformly by
revenue across the revenue range. Once the revenue "break point" was reached, offices from the
next higher number-of-chairs range were assigned to the remaining offices in the revenue range,
and successively higher revenue ranges until that part of the chairs distribution was "used up."
This process was repeated until all offices by "number of chairs" were assigned across all
revenue ranges.
Table 10-6 summarizes the assignment process and results for the ADA Colorado Study
and ADA National Study number-of-chair distributions. The table reports the assignment by
revenue range and number of chairs for all offices, regardless of baseline status, with the
exception of large institutional facilities. Large institutional facilities are not included in this tally
because EPA possesses no information on their revenue.
26 Exceptions to this assumption would include a dental office with exclusive clientele (i.e., an office with a small
number of chairs that is in a higher revenue range). EPA did not have data to evaluate these exclusive clientele
dental offices and therefore finds it reasonable to assume on a national basis that number of chairs in a dental office
increases with office revenue.
10-11
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Table 10-6. Number of Chairs in Dental Offices by Revenue Range
Revenue Range Values ($2010)
(see Table 10-2)
Low
High
Offices By Revenue Range
(see Table 10-2)
Number of
Offices
Percent of
Total
Offices
Running
Total
Percent
Number
of
Chairs
With Allocation by Number of Chairs in Office
Number
of Offices
Running
Total
Percent of
Total
Offices
Running
Total
Percent
Cumulative
Percent from ADA
Distribution
Using ADA Colorado Study Distribution
0
$10,449
$26,121
$52,243
$104,486
$193,477
$261,214
$478,569
$522,428
$879,905
$1,044,857
$1,242,939
$1,868,021
$2,612,142
$5,224,284
$10,448,568
Total27
$10,448
$26,120
$52,242
$104,485
$193,476
$261,213
$478,568
$522,427
$879,904
$1,044,856
$1,242,938
$1,868,020
$2,612,141
$5,224,283
$10,448,567
Or more
174
513
1,023
2,613
14,183
31,303
46,578
27,255
3,028
330
58
127,057
0.1%
0.4%
0.8%
2.1%
11.2%
24.6%
36.7%
21.5%
2.4%
0.3%
0.1%
100.00%
0.1%
0.5%
1.4%
3.4%
14.6%
39.2%
75.9%
97.3%
99.7%
99.9%
100.00%
1-2
1-2
1-2
1-2
1-2
3
3
4
4
5
5
6
7+
7+
7+
7+
—
174
513
1,023
2,613
8,053
6,130
26,047
5,256
31,871
14,706
3,445
10,870
12,940
3,028
330
58
127,057
174
687
1,710
4,322
12,376
18,506
44,552
49,808
81,680
96,386
99,831
110,700
123,641
126,669
126,999
127,057
0.1%
0.4%
0.8%
2.1%
6.3%
4.8%
20.5%
4.1%
25.1%
11.6%
2.7%
8.6%
10.2%
2.4%
0.3%
0.1%
100.00%
0.1%
0.5%
1.4%
3.4%
9.7%
14.6%
35.1%
39.2%
64.3%
75.9%
78.6%
87.1%
97.3%
99.7%
99.9%
100.00%
9.74%
35.06%
64.29%
78.57%
84.42%
100.00%
Using ADA National Study Distribution
0
$10,449
$26,121
$52,243
$104,486
$231,732
$261,214
$522,428
$760,148
$1,044,857
$10,448
$26,120
$52,242
$104,485
$231,731
$261,213
$522,427
$760,147
$1,044,856
$1,539,698
174
513
1,023
2,613
14,183
31,303
46,578
27,255
0.1%
0.4%
0.8%
2.1%
11.2%
24.6%
36.7%
21.5%
0.1%
0.5%
1.4%
3.4%
14.6%
39.2%
75.9%
97.3%
1-2
1-2
1-2
1-2
1-2
3^
3^
3^
5-6
5-6
174
513
1,023
2,613
11,515
2,668
31,303
21,194
25,383
8,605
174
687
1,710
4,322
15,838
18,506
49,808
71,002
96,386
104,991
0.1%
0.4%
0.8%
2.1%
9.1%
2.1%
24.6%
16.7%
19.9%
6.8%
0.1%
0.5%
1.4%
3.4%
12.5%
14.6%
39.2%
55.9%
75.9%
82.6%
12.46%
55.88%
82.63%
o
§
o
I
3
P
27 The total 127,057 offices include the entire dental industry, including those dental specialists discussed in Section 4.2 that are outside the scope of the proposed rule.
-------
Table 10-6. Number of Chairs in Dental Offices by Revenue Range
Revenue Range Values ($2010)
(see Table 10-2)
Low
$1,539,699
$2,612,142
$5,224,284
$10,448,568
Total
High
$2,612,141
$5,224,283
$10,448,567
Or more
Offices By Revenue Range
(see Table 10-2)
Number of
Offices
3,028
330
58
127,057
Percent of
Total
Offices
2.4%
0.3%
0.1%
100.00%
Running
Total
Percent
99.7%
99.9%
100.00%
Number
of
Chairs
7+
7+
7+
7+
—
With Allocation by Number of Chairs in Office
Number
of Offices
18,650
3,028
330
58
127,057
Running
Total
123,641
126,669
126,999
127,057
Percent of
Total
Offices
14.7%
2.4%
0.23%
0.1%
100.00%
Running
Total
Percent
97.3%
99.7%
99.9%
100.00%
Cumulative
Percent from ADA
Distribution
100.00%
Source: U.S. EPA, 201 Ic.
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-------
Section 10 - Economic Impacts for the Dental Industry
10.3 ESTIMATED COST OF COMPLIANCE TO DENTAL OFFICES
To estimate the total nationwide cost of compliance to dental offices of the proposed rule,
EPA multiplied the estimated total annualized cost of rule compliance by the number of chairs
for dental offices (see Section 10.1.2). For large institutional facilities, compliance costs are
multiplied by the estimated number of facilities in the resulting size ranges (see Table 10-6 and
Table 10-8). EPA then added these values over the size ranges to yield the total estimated
compliance cost. These calculations account for baseline compliance status (i.e., whether offices
are assumed to have already installed amalgam separators). These costs are the pre-tax costs
estimated to be incurred by complying entities— dental offices and large institutional facilities—
as of the year of compliance.
EPA completed these calculations separately for the two distributions of offices by
number of chairs. Table 10-7 summarizes the results from these calculations. These total
compliance cost estimates include the one-time compliance costs for dental offices that do not
process dental amalgam, as described in Section 10.2.1.
Table 10-7. Annualized Costs to Complying Dental Offices by Number of
Chairs
Annualized Cost (Millions, $2010) for Alternative Number-of-Chairs Distributions
Number of Chairs
1-2 chairs
3 chairs
4 chairs
5 chairs
6 chairs
7+ chairs
Large facilities
Total Costs
Colorado Survey
$3.8
$10.7
$12.3
$6.0
$5.3
$10.7
$0.1
$49.0
ADA Survey
$4.9
$18.3
$16.7
$14.4
$0.1
$54.5
Present values and annualized costs are calculated using a 7 percent discount rate. All costs
are on a pre-tax basis, in $2010, and as of the time of compliance by complying entities.
Source: U.S. EPA, 20lie.
Costs are higher for the ADA National Study data distribution compared to the ADA
Colorado Study data distribution because the ADA National Study data distribution estimates
more higher-number-of-chair offices than does the ADA Colorado Study data distribution. For
example, 44 percent of offices are estimated to have five or more chairs under the ADA National
Study data distribution compared to 36 percent of offices under the ADA Colorado Study data
distribution. Both estimates cover the same number of offices/facilities.
10.3.1 Economic Impact of Compliance Costs
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 (Section 10.3.1.1). 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 (Section 10.3.1.2); and (2)
10-14
-------
Section 10 - Economic Impacts for the Dental Industry
ratio of the proposed rule's capital costs to annual dental office capital replacement costs
(Section 10.3.1.3).
10.3.1.1
Cost-to-Revenue Analysis
The cost-to-revenue measure compares the annualized cost of regulatory compliance, at a
seven percent discount rate, with the revenue of regulated dental offices, and provides a
screening-level assessment of the impact of compliance costs on dental offices. The cost-to-
revenue measure assesses the loss in operating profit, on a constant annual cost basis, as a
percentage of baseline revenue that a business would incur if none of the compliance costs were
passed forward to customers. In using this impact measure, EPA assesses whether the
compliance cost exceeds thresholds of one and three percent of revenue. This impact measure is
also used in the Regulatory Flexibility Act assessment, described in Section 10.5 below.
EPA framed the cost-to-revenue analysis around the revenue range/number-of-chairs
combinations, as developed in Table 10-6, and the total annualized compliance costs that would
occur within each of these analysis combinations. Table 10-8 summarizes these analytic
combinations. Note that EPA was not able to perform the cost-to-revenue impact analysis for
large institutional facilities, as it has no revenue information for them. However, since EPA
performed the cost-to-revenue analysis on a range of office sizes, EPA projects the results of this
analysis would be similar for large institutional facilities.
In general, EPA assessed that cost impact analyses should be performed using after-tax
costs, as these costs account for the reduction in costs to affected entities resulting from tax
deductibility of the outlays, and thus provide a better indication of the financial impact of
regulatory requirements on complying entities. In the cost-to-revenue analysis for the proposed
Dental Amalgam Rule, EPA used costs on a pre-tax instead of after-tax basis, because the
appropriate tax rates for complying entities, which are often sole proprietorships or partnerships,
are not known. Using pre-tax instead of after-tax costs increases the likelihood of finding that
costs exceed the one percent or three percent of revenue impact threshold.
Table 10-8. Revenue Range/Number-of-Chairs
Combinations for Cost Impact Analysis
Revenue Range/Number of Chairs Combinations
Low | High
Number of Chairs
Number of
Offices
Percent of Total
Offices
Using ADA Colorado Study Distribution
0
$10,449
$26,121
$52,243
$104,486
$193,477
$261,214
$478,569
$522,428
$879,905
$1,044,857
$1,242,939
$1,868,021
$2,612,142
$10,448
$26,120
$52,242
$104,485
$193,476
$261,213
$478,568
$522,427
$879,904
$1,044,856
$1,242,938
$1,868,020
$2,612,141
$5,224,283
1-2
1-2
1-2
1-2
1-2
3
3
4
4
5
5
6
7+
7+
151
443
884
2,259
6,963
5,300
22,521
4,545
27,557
12,716
2,978
9,399
11,189
2,619
0.1%
0.4%
0.8%
2.1%
6.3%
4.8%
20.5%
4.1%
25.1%
11.6%
2.7%
8.6%
10.2%
2.4%
10-15
-------
Section 10 - Economic Impacts for the Dental Industry
Table 10-8. Revenue Range/Number-of-Chairs
Combinations for Cost Impact Analysis
Revenue Ran
Low
$5,224,284
$10,448,568
ge/Number of Chairs Combinations
High
$10,448,567
Or more
Number of Chairs
7+
7+
Total
Number of
Offices
285
50
109,859
Percent of Total
Offices
0.3%
0.1%
100.00%
Using ADA National Study Distribution
0
$10,449
$26,121
$52,243
$104,486
$231,732
$261,214
$522,428
$760,148
$1,044,857
$1,539,699
$2,612,142
$5,224,284
$10,448,568
$10,448
$26,120
$52,242
$104,485
$231,731
$261,213
$522,427
$760,147
$1,044,856
$1,539,698
$2,612,141
$5,224,283
$10,448,567
Or more
-2
-2
-2
-2
-2
3^
3^
3^
5-6
5-6
7+
7+
7+
7+
Total
151
443
884
2,259
9,957
2,307
27,066
18,325
21,948
7,440
16,125
2,619
285
50
109,85928
0.1%
0.4%
0.8%
2.1%
9.1%
2.1%
24.6%
16.7%
20.0%
6.8%
14.7%
2.4%
0.3%
0.1%
100.00%
Source: U.S. EPA, 201 Ic.
Costs of compliance were assigned to each revenue range/number-of-chairs combination
and then assessed relative to the low and high revenue values of a revenue range to determine
whether offices within the revenue range would incur costs exceeding a given percent of revenue
threshold. For each revenue range/number-of-chairs combination and a given percent of revenue
threshold — i.e., one or three percent — EPA evaluated three cases:
1. If the calculated cost-to-revenue percentage is less than the threshold value at the low
end of the revenue range, then EPA assessed that none of the dental offices in that
revenue range would incur costs exceeding the given percent of revenue threshold.
2. If the calculated cost-to-revenue percentage exceeds the threshold value at the high
end of the revenue range, then EPA assessed that all of the dental offices in that
revenue range would incur costs exceeding the given percent of revenue threshold.
3. If neither of the two prior conditions are met, this indicates that some, but not all, of
the offices in the revenue range would exceed the percent of revenue threshold. To
determine the number of offices exceeding the given percent of revenue threshold,
EPA calculated the "break-even" revenue value for a given compliance cost and
percent of revenue threshold, by dividing the compliance cost value by the given
percent of revenue threshold. This break-even value is the revenue value at which
compliance cost equals the percent of revenue threshold; offices with revenue below
the break-even value will incur costs exceeding the given percent of revenue
threshold, while offices with revenue above it will incur costs below the percent of
The total 109,859 dental offices are all in-scope dental offices for the proposed Dental Amalgam Rule as
described in Section 10.1.2. The total does not include large facilities as noted in this section.
10-16
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Section 10 - Economic Impacts for the Dental Industry
revenue threshold. To calculate the number of offices with costs exceeding the
percent of revenue threshold, EPA assumed that offices are distributed uniformly
within the revenue range and calculated the fraction of offices below the break-even
value as follows:
Fraction exceeding threshold = (RVbe - RVmin) •*• (RVmax - RVmin)
Where:
RVbe = Break-even revenue
RVmin = Minimum value in revenue range
RVmax = Maximum value in revenue range
EPA tallied the estimated fraction of offices within each number-of-chairs/revenue range
combination that exceed a given percent of revenue threshold. Results were developed separately
for both the ADA Colorado Study and ADA National Study chairs-by-office distributions and
accounting for technology-in-place status.
Because EPA does not have detailed data on baseline financial conditions of dental
offices, the effect of the proposed pretreatment standard on dental office income statements and
balance sheets cannot be measured by a closure analysis (as is EPA's more typical practice for
analyzing economic achievability). 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. 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; see Table 10-1). 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:
• A low-revenue office could be a single-dentist and/or part-time business that provides
services as a subcontractor on an independent fee-for-service basis, such as dental
hygiene, in a general service dental office that is 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 the proposed 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. Alternatively, if these operators offer their services in a competitive market, it
may be that none of the compliance costs are shared by these subcontractors.
• Another possibility is that some of these very low-revenue offices could be non-profit
groups that provide pay-as-you-can or free services to 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).
• Alternatively, these very low revenue establishments could be non-viable as for-profit
businesses, if they are attempting to operate as general service dental practices. This
reasoning is based on EPA's assessment of the ongoing outlay required for
replacement of existing dental office capital equipment, which was performed for the
third part of the cost impact analysis (Section 10.3.1.3, below). Specifically, in this
10-17
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Section 10 - Economic Impacts for the Dental Industry
analysis, EPA estimated that one- to two-chair offices would incur capital
replacement costs of approximately $23,500 per year (the estimated annual cost of
keeping equipment in good working order) (U.S. EPA, 201 Ic). This outlay would
exceed or represent a very substantial fraction of annual revenue of the business in the
below-$25,000 revenue range. Accordingly, these offices may not be operating viably
as general service dental offices.
Given these considerations, EPA performed the cost-to-revenue analysis on two bases:
• Excluding the low-revenue offices (below $23,500 revenue) from the cost-to-revenue
analysis.
• Including the low-revenue offices in the cost-to-revenue analysis.
For the rest of the economic analysis chapter, EPA refers to the low-revenue offices as
baseline set-aside offices.
Following the methodology outlined above, EPA estimated the occurrence of cost-to-
revenue exceeding the one and three percent of revenue thresholds for the proposed rule for the
ADA Colorado Study and ADA National Study chairs-by-office distributions. As described
above, EPA accounted for the number of offices estimated to have already installed amalgam
separator technology, and the resulting compliance cost for these cases, in the cost-to-revenue
calculations. Table 10-9 and Table 10-10 summarize the results from this analysis. Table 10-9
reports the results by technology-in-place status; Table 10-10 reports the results by number-of-
chair ranges. These findings are the same for both the ADA National Study and ADA Colorado
Study chairs-by-office distributions.
With the baseline set-aside offices excluded from the analysis, EPA estimates that 507
dental offices would incur costs exceeding one percent of revenue, representing 0.5 percent of
dental offices expected to incur costs under the proposed regulation. No offices incur costs
exceeding three percent of revenue. With the baseline set-aside offices included in the analysis,
EPA estimates that 965 dental offices would incur costs exceeding one percent of revenue,
representing 0.9 percent of dental offices expected to incur costs under the proposed rule; 221
offices are estimated to incur costs exceeding three percent of revenue, representing 0.2 percent
of offices expected to incur costs under the proposed rule.
Of note, all of the instances in which the cost-to-revenue impact value exceeds one or
three percent occur among dental offices in revenue ranges below the small business revenue
threshold of $7.0 million. This finding is relevant for Section 10.5.
Table 10-9. Cost-to-Revenue Impact Summary
Offices with Cost Exceeding 1 Percent of Revenue
Technology-
In-Place
No-Tech-
in-Place
Total
Percentage
Offices with Cost Exceeding 3 Percent of Revenue
Technology-
In-Place
No-Tech- Total
in-Place |
Percentage
Excluding Baseline Set-Aside Offices from Analysis
33
474
507
0.5%
0
0 | 0
0.0%
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Section 10 - Economic Impacts for the Dental Industry
Table 10-9. Cost-to-Revenue Impact Summary
Offices with Cost Exceeding 1 Percent of Revenue
Technology-
In-Place
No-Tech-
in-Place
Total
Percentage
Offices with Cost Exceeding
Technology-
In-Place
No-Tech-
in-Place
13 Percent of Revenue
Total
Percentage
Including Baseline Set-Aside Offices in Analysis
243
722
965
0.9%
51
169
221
0.2%
Calculations exclude the estimated 13,000 offices with no-technology-in-place that do not place or remove dental
amalgam (and thus will incur only a minimal one-time reporting cost).
Percentages of affected offices are calculated as a fraction of total offices estimated to incur costs under the
proposed Dental Amalgam Rule.
Source: U.S. EPA, 201 Ic.
Table 10-10. Cost-to-Revenue Impact Summary by Number of Chairs
Number of
Chairs
1-2 chairs
3 chairs
4 chairs
5 chairs
6 chairs
7+ chairs
Total
Excluding Baseline Set-Aside Offices from
Analysis
Costs >1% Rev.
Number
507
—
—
—
—
—
507
%
4.2%
0.0%
0.0%
0.0%
0.0%
0.0%
0.5%
Costs >3% Rev.
Number
—
—
—
—
—
—
—
%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
Including Baseline Set-Aside Offices in
Analysis
Costs >1% Rev.
Number
965
—
—
—
—
—
965
%
7.9%
0.0%
0.0%
0.0%
0.0%
0.0%
0.9%
Costs >3% Rev.
Number
221
—
—
—
—
—
221
%
1.8%
0.0%
0.0%
0.0%
0.0%
0.0%
0.2%
Percentages of affected offices are calculated as a fraction of total offices estimated to incur costs under the
proposed Dental Amalgam Rule.
Source: U.S. EPA, 201 Ic.
From this analysis, due to the small percentage of offices potentially incurring costs over
one percent or three percent of revenue, EPA finds that the proposed rule would not have a
material adverse impact on the dental office sector.
10.3.1.2 Ratio of the Proposed Rule's Capital Costs to Total Dental Office Capital
Assets
From the preceding analysis, EPA found that the proposed rule will have minimal impact
on operating finances given that less than one percent of dental offices may incur annualized
compliance costs exceeding one or three percent of revenue. Given this finding, it is possible that
the more material impact of the proposed Dental Amalgam Rule could result from the need of
dental offices to finance the initial outlays required for rule compliance — in particular,
technology purchase and installation. Accordingly, EPA undertook two additional analyses of
potential impact based on the requirement to finance the initial outlay. The first of these,
presented in this section, examines the initial outlay in relation to the baseline value of assets on
the balance sheet of dental office businesses. The second analysis, presented in the next section
(Section 10.3.1.3), examines the initial outlay in relation to the estimated steady state outlays for
capital replacement for the dental office business. The steady state capital replacement outlay
represents a value dental offices may reasonably expect to spend in the periodic outlays to
replace and/or upgrade dental office capital equipment. For both tests, EPA assumed that a low
ratio implies limited impact on dental offices' ability to finance the initial spending on
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Section 10 - Economic Impacts for the Dental Industry
compliance 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.
For the analysis of capital outlays in relation to baseline assets, EPA relied on data from
Risk Management Association (RMA)29 to estimate the baseline assets of dental offices by
revenue range. Specifically, EPA used asset to sales ratios for the dental office sector to estimate
an asset value for the minimum and maximum revenue values for each of the revenue
range/number of chairs combinations as analyzed in the preceding section. Each revenue
range/number of chairs combination then has a minimum and maximum asset value for use in
the capital outlay to baseline asset value analysis. The RMA data have the limitation that they
may not be fully representative of all dental offices, because they only represent dental offices
that are successful borrowers. Hence, the RMA data may underrepresent offices that are not
financially healthy. This would cause EPA's finding of impact to understate the actual impacts.
Using the same approach to assigning compliance requirements to the revenue
range/number-of-chairs analysis combinations, as described in Section 10.3.1.1, EPA then
assigned the initial outlays only to the revenue range/number-of-chairs analysis combinations.
The values of initial outlays were then compared to the minimum and maximum values of each
revenue range/number-of-chairs analysis combination to assess the potential capital
outlay/financing burden. In the same way as described for the preceding cost-to-revenue
analysis, the capital outlay to baseline asset value analysis accounted for whether offices have
already installed amalgam separator technology and also used the alternative number of chairs by
office distributions (ADA Colorado Study and ADA National Study). Also, EPA performed this
analysis both including and excluding the baseline set-aside offices. For the analysis including
the baseline set-aside offices, EPA assumed a minimum revenue value of $5,000 (and the
corresponding baseline assets value) for the lowest revenue range, to prevent division by zero.
Table 10-11 reports the findings from this analysis, specifically the average outlay-to-
assets ratio values by operating size (number of chairs), and the weighted average of the outlay -
to-assets ratio across the number-of-chairs ranges. As with the cost-to-revenue impact analysis,
EPA did not perform this analysis for the large institutional facilities, as it has no financial data
on which to base the analysis. However, since EPA performed this analysis on a range of office
sizes, EPA projects that the results of this analysis would be similar for large institutional
facilities.
Table 10-11. Comparing Total Initial Outlay to Baseline Assets
Initial Compliance Outlay as Percentage of Baseline Assets
(Outlay-to-Assets, OTA)
Excluding Baseline Set- Aside Offices from Analysis
Number of Chairs
1-2 chairs
3 chairs
4 chairs
5 chairs
Technology-in-Place
Low
0.1%
0.0%
0.0%
0.0%
High
0.1%
0.0%
0.0%
0.0%
No Technology-in-Place
Low
2.7%
0.8%
0.5%
0.3%
High
1.3%
0.5%
0.3%
0.2%
RMA 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.
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Section 10 - Economic Impacts for the Dental Industry
Table 10-11. Comparing Total Initial Outlay to Baseline Assets
Initial Compliance Outlay as Percentage of Baseline Assets
(Outlay-to-Assets, OTA)
Excluding Baseline Set- Aside Offices from Analysis
Number of Chairs
6 chairs
7+ chairs
Total
Technology-in-Place
Low
0.0%
0.0%
0.0%
High
0.0%
0.0%
0.0%
No Technology-in-Place
Low
0.3%
0.2%
0.7%
High
0.2%
0.2%
0.4%
Including Baseline Set-Aside Offices in Analysis
Number of Chairs
1-2 chairs
3 chairs
4 chairs
5 chairs
6 chairs
7+ chairs
Total
Technolo
Low
0.2%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
Ły-in-place
High
0.1%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
No Technology-in-place
Low
3.7%
0.8%
0.5%
0.3%
0.3%
0.2%
0.8%
High
1.7%
0.5%
0.3%
0.2%
0.2%
0.2%
0.5%
Source: U.S. EPA, 20lie.
With baseline set-asides excluded from the analysis, the resulting initial capital costs to
total capital assets values are low, with an average value of 0.4 percent to 0.7 percent for no-
technology-in-place offices and 0 percent for the technology-in-place offices. With baseline set-
asides included in the analysis, the resulting initial capital costs to total capital assets values are
low, with an average value 0.5 percent to 0.8 percent for the no-technology-in-place offices and
0 percent for the technology-in-place offices.
EPA finds these results to indicate that dental offices should not encounter difficulty in
financing the increase in assets that would result from installing amalgam separators.
10.3.1.3 Ratio of the Proposed Rule's Capital Costs to Annual Dental Office Capital
Replacement Costs
As another test of the potential burden of financing the initial outlays for rule compliance,
EPA compared the initial outlay with estimated steady state outlays for capital replacement for
the dental office business. As stated above, the steady state capital replacement outlay represents
a value dental offices may reasonably expect to spend in the periodic outlays to replace and/or
upgrade dental office capital equipment. EPA assumed 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.
For this comparison, 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 and Child Oral Health Resource Center at Georgetown University. This
publication reports overall costs in broad categories of major and small items for two specific
number-of-chair offices (three chairs and six chairs) and provides additional detail on specific
equipment needs for the six-chair office, including the estimated service life for the various items
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Section 10 - Economic Impacts for the Dental Industry
of equipment. EPA worked with these data in several ways to develop an estimate of the steady
state capital replacement outlay:
• EPA used the detailed cost and service life information for the six-chair office to
develop a profile of startup outlays by service life and developed percentages of total
startup outlay by service life for two broad categories of major and small items (see
Table 10-12).
• EPA used the aggregate cost information by the major and small item categories, for
the three- and six-chair offices, to estimate startup outlays for other number-of-chair
offices to be accounted for in the analysis. EPA interpolated between and/or
extrapolated from the three- and six-chair office values to develop the startup cost
estimates for the other chair size offices, including additional analysis for the eight-
and nine-chair offices. EPA adjusted some of the values for the one- or two-chair
office to reflect the fact that some equipment needs have a minimum number and/or
cost regardless of how few chairs are in the office. The first section of Table 10-13.
"Initial Outlays" by major and small items, reports the results from this step (EPA
assumed initial compliance outlay for eight- and nine-chair offices is the same as a
seven-chair office).
• EPA allocated the broad components of cost — major and small items — for each
office size, into the specific service life categories based on the service life
percentages reported in Table 10-12. The second section of Table 10-13, "Initial
Outlays by Equipment Life Category," reports the results from this step.
• To estimate a steady-state replacement outlay, EPA divided the estimated outlays for
each service life category by the number of years for the service life category, and
summed these values over the service life categories for each of the number-of-chair
office specifications. EPA recognizes that outlays for capital replacement and/or
refurbishment will not generally occur on a uniform basis from year to year, but on
average, over a period of several years, the annual replacement and/or refurbishment
outlay should be approximately this "steady state" value. The third section of Table
10-13, "Steady State Annual Replacement Outlay, by Equipment Life Category,"
reports the results from this step.
Table 10-12. Composition of Dental Equipment for Six-Chair
Office by Equipment Life
Useful Life Category
3
5
10
12
15
Total
Percent of Value by Service Life Category
Major Items
$0
$52,300
$79,125
$6,850
$104,545
$242,820
Percent
0.0%
21.5%
32.6%
2.8%
43.1%
100.0%
Small Items
$19,800
$0
$72,138
$0
$0
$91,938
Percent
21.5%
0.0%
78.5%
0.0%
0.0%
100.0%
Based on 6-chair office specifications from Georgetown University, 2003.
10-22
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Section 10 - Economic Impacts for the Dental Industry
Table 10-13. Initial and Annual Replacement Outlay for
Startup Dental Office by Number of Chairs
Number of Chairs
1-2
3
4
5
6
7
8
9
Initial Outlays
Major
items
Small items
Total
$165,036
$39,082
$204,553
$185,234
$52,218
$237,452
$219,220
$68,195
$287,415
$253,207
$84,172
$337,379
$287,193
$100,149
$387,342
$321,179
$116,126
$437,305
$355,166
$132,103
$487,269
$389,152
$148,080
$537,232
Initial Outlays by Equipment Life Category
3
5
10
12
15
Total
$8,417
$35,640
$84,585
$4,668
$71,243
$204,553
$11,246
$39,897
$101,332
$5,225
$79,752
$237,452
$14,687
$47,217
$124,943
$6,184
$94,384
$287,415
$18,127
$54,537
$148,554
$7,143
$109,017
$337,379
$21,568
$61,857
$172,165
$8,102
$123,650
$387,342
$25,009
$69,177
$195,776
$9,061
$138,282
$437,305
$28,450
$76,498
$219,387
$10,019
$152,915
$487,269
$31,891
$83,818
$242,998
$10,978
$167,548
$537,232
Steady State Annual Replacement Outlay, by Equipment Life Category
3
5
10
12
15
Total
$2,806
$7,128
$8,459
$389
$4,750
$23,531
$3,749
$7,979
$10,133
$435
$5,317
$27,613
$4,896
$9,443
$12,494
$515
$6,292
$33,641
$6,042
$10,907
$14,855
$595
$7,268
$39,668
$7,189
$12,371
$17,216
$675
$8,243
$45,696
$8,336
$13,835
$19,578
$755
$9,219
$51,723
$9,483
$15,300
$21,939
$835
$10,194
$57,751
$10,630
$16,764
$24,300
$915
$11,170
$63,778
Source: U.S. EPA, 201 Ic.
As the final step in this analysis, EPA compared the estimated total initial outlay for the
proposed Dental Amalgam Rule to the estimated steady state annual replacement outlay values,
from Table 10-13. Table 10-14 reports the results from this comparison. As shown in Table
10-14 the values for initial compliance outlay as a percentage of replacement outlay are quite
low, ranging from 2.2 percent to 3.5 percent, with a weighted average of 2.9 percent across all
number-of-chair ranges.
10-23
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Table 10-14. Comparing Total Initial Compliance Outlay to Steady State Annual Replacement Outlay by Number of
Chairs (Section 10.3.1.3)
Initial compliance
outlay
Baseline annual
replacement outlay
Initial compliance
outlay as percentage
of replacement outlay
Number of Chairs
1-2
$789
$23,531
3.4%
3
$886
$27,613
3.2%
4
$886
$33,641
2.6%
5
$886
$39,668
2.2%
6
$1,345
$45,696
2.9%
7
$1,818
$51,723
3.5%
8
$1,818
$57,751
3.1%
9
$1,818
$63,778
2.9%
Weighted
Average
2.9%
Source: U.S. EPA, 201 Ic.
Table 10-15. Comparing Total Initial Compliance Outlay to Initial Outlay by Number of Chairs (Section 10.3.1.4)
Initial compliance outlay
Initial outlay
Initial compliance outlay
as percentage of office
startup costs
Number of Chairs
1-2
$789
$204,553
0.4%
3
$886
$237,452
0.4%
4
$886
$287,415
0.3%
5
$886
$337,379
0.3%
6
$1,345
$387,342
0.3%
7
$1,818
$437,305
0.4%
8
$1,818
$487,269
0.4%
9
$1,818
$537,232
0.3%
Weighted
Average
0.3%
ft
w
o
o
8
3
o'
KH
I
O
Source: U.S. EPA, 201 Ic.
if
a
s
El
-------
Section 10 - Economic Impacts for the Dental Industry
10.3.1.4 Economic Impact for New Sources
EPA assessed whether the proposed pretreatment standard for new sources would impose
a barrier to entry. To perform this analysis, EPA relied on data describing the equipment needs
and costs for starting a dental office as compiled in the Safety Net Dental Clinic Manual.,
prepared by the National Maternal and Child Oral Health Resource Center at Georgetown
University. EPA calculated the initial outlay to start a dental office as shown above in Table
10-13. EPA then compared the initial compliance cost for dental offices as estimated in Section
10.2 to these startup values. This comparison demonstrates that the amalgam separator capital
costs would represent only 0.3 percent to 0.4 percent of the cost of starting a dental office and,
therefore, do not pose a barrier to entry (see Table 10-15 above).
10.4 SOCIAL COST OF THE PROPOSED DENTAL AMALGAM RULE
The previous sections reviewed the estimated costs of the proposed Dental Amalgam
Rule to dental offices and facilities and assessed the potential impact of the proposed rule on
these offices and facilities. This section reviews the costs of the proposed Dental Amalgam Rule
from the standpoint of cost to society, or social cost. The assessment of social cost builds from
the estimated costs of regulatory compliance, as described in Section 10.2.1, but differs from the
assessment of costs to dental offices in the following respects:
• The assessment of cost of compliance to dental offices used a discount rate of seven
percent for developing present and annualized values. As described previously, the
seven percent discount rate represents an estimated opportunity cost of capital to
society, on a pre-tax, constant dollar basis. The analysis of social cost uses an
additional discount rate, three percent, which represents a societal rate of time
preference — the rate at which society desires to be compensated for deferring
consumption from one year to the next. Social costs are presented on the basis of both
three and seven percent discount rates.
• The assessment of cost of compliance to dental offices included only the costs
incurred by these offices. The assessment of social cost includes these costs of
compliance, but also includes an additional cost that will be incurred by society,
namely the cost to permitting authorities for administering the proposed Dental
Amalgam Rule.
• The assessment of cost of compliance to dental offices developed present values and
annualized costs as of the time at which dental offices would comply with the rule's
requirements, regardless of the specific calendar year in which compliance would
occur. The assessment of social cost develops present and annualized values as of the
expected year of rule promulgation, 2012, and the compliance period three years
following promulgation, in 201530. Specifically, using the analytic convention
outlined previously for the assessment of compliance costs to dental offices, costs are
first developed over an assumed 20-year compliance period, which reflects initial
installation of compliance equipment at the first year of compliance, and then
reinstallation at the 11th year of the 20-year analysis period. These costs are
30 EPA completed its economic impact analysis assuming a promulgation date of 2012. EPA does not expect the
results of the social cost analysis would significantly change due to a later promulgation date.
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Section 10 - Economic Impacts for the Dental Industry
discounted to the year of compliance and then annualized over the 20 years of rule
compliance. These present and annualized values, which are assumed to be as of
2015, or the first year of required compliance, are then discounted an additional three
years to 2012, the year of rule promulgation.
In assessing social costs, EPA assumed that the regulation would result in no change in
the total quantity of services provided by the dental industry. Thus, the social cost analysis
includes no loss in economic surplus to society due to contraction of dental industry output, and
the social cost estimate includes only the resource costs of compliance and rule administration.
Given that the rule's total annualized costs are estimated to represent less than 0.1 percent of the
total value of dental services, based on 2007 Economic Census values expressed in 2010 dollars,
EPA assesses that the assumption of no change in industry output is reasonable.
10.4.1 Cost of Compliance on Social Cost Basis
For the analysis of social cost, compliance costs are developed on the same basis as
described in Section 10.2, with the exceptions, as noted above, that costs are calculated on a
present value and annualized cost basis as of the year of rule promulgation, 2012, and using three
percent and seven percent discount rates. Table 10-16 summarizes these cost values for the
proposed rule by the alternative number-of-chair distributions.
Table 10-16. Compliance Costs on a Social Cost Basis for Proposed Dental Amalgam Rule
Annualized Cost (Millions, $2010) as of 2012, Year of Rule Promulgation
Compliance cost
Using 3 Percent Discount Rate
Colorado Survey
$43.6
ADA Survey
$48.5
Using 7 Percent Discount Rate
Colorado Survey
$40.0
ADA Survey
$44.5
Source: U.S. EPA, 20lie.
10.4.2 Administrative Costs
As described above, these costs are calculated for the year of rule promulgation, 2012, as
$833,000 at a three percent discount rate and $790,000 at a seven percent discount rate. As
discussed in Section 1.2.3, the Control Authority could be the publicly owned treatment works
(POTW), the state, or U.S. EPA Region. EPA estimated the annual recordkeeping costs and
recurring costs (recordkeeping, inspections, reporting, and enforcement) for the following
Control Authorities:
• 403.10(e) States: 5 Control Authorities;
• POTWs: 1,600 Control Authorities;31
• Approved Pretreatment States (minus the 403.10(e) States): 31 Control Authorities;
and
• U.S. EPA Regions: 9 Control Authorities.32
EPA used a labor rate estimate of $55.18/hour33 for these Control Authorities and an
appropriate time estimate for each activity mentioned above (e.g., recordkeeping) (U.S. EPA,
31 Estimated approved Control Authority POTWs nationwide via U.S. EPA, 201 Ib.
32 All states in Region 4 have approved pretreatment programs, so the state has the approval authority.
10-26
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Section 10 - Economic Impacts for the Dental Industry
201 le). See DCN DA00147. Annual costs were assumed to meet a five-year compliance
schedule. Administrative costs were assumed over a three-year period, because of the
pretreatment standards program information collection request (ICR) that is completed every
three years (U.S. EPA, 201 le and 201 Id).
10.4.3 Total Social Cost
Table 10-17 summarizes the estimated total social cost for the proposed Dental Amalgam
Rule, including both compliance costs and administrative costs. Costs are reported by the
alternative number-of-chair distributions and for the three and seven percent discount rates.
Table 10-17. Summary of Social Cost for Proposed Dental Amalgam Rule
Annualized Cost (Millions, $2010) as of 2012, Year of Rule Promulgation
Cost Category
Compliance cost
Cost to permitting authorities
Total social cost
Using 3 Percent Discount Rate
Colorado Survey
$43.6
$0.9
$44.5
ADA Survey
$48.5
$0.9
$49.4
Using 7 Percent Discount Rate
Colorado Survey
$40.0
$0.8
$40.8
ADA Survey
$44.5
$0.8
$45.2
10.5 REGULATORY FLEXIBILITY ACT ASSESSMENT
As part of the cost and economic impact assessment for the proposed Dental Amalgam
Rule, EPA considered the potential impact on small entities in the dental office business. Of key
concern in this assessment is whether the proposed Dental Amalgam Rule could cause a
significant impact on a substantial number of small entities (SISNOSE).
As reported previously, the Small Business Administration criterion for defining a small
entity in the dental office sector (NAICS 621210) is $7.0 million in revenue. In the same way as
for the previous general economic impact analysis, EPA framed its small entity analysis around
establishments, or individual dental offices, instead of using the firm. Because nearly 98 percent
of small dental office firms are single establishment businesses, there is minimal difference in
performing this analysis at the level of the dental office compared to the dental firm.
To estimate the number of number of small business dental offices, EPA relied on dental
office counts from the Economic Census, as used elsewhere in this analysis. EPA first segmented
the Economic Census revenue range that contains the small business criterion into office counts
that are above and below the criterion, assuming that offices are uniformly distributed across this
revenue range according to revenue size. This segmentation applies to less than one percent of
the total number of small businesses in the dental office sector, so the error introduced by
assuming a uniform distribution is minor, at most, in the overall analysis.
In addition, as described previously, EPA also estimated that some in-scope dental offices
do not process dental amalgam, and thus would be expected to incur no or limited costs under
the proposed Dental Amalgam Rule.
33 Metal products and machinery 150 POTW Study ($1999). EPA took the $1999 and using the Bureau of
Employment Cost Index for State and Local Government Public Administration converted to $2010 (U.S. EPA,
2000).
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Section 10 - Economic Impacts for the Dental Industry
Based on these adjustments, EPA estimated that approximately 126,800 dental offices are
small businesses and that approximately 109,600 of these small business dental offices are in
scope for the proposed rule and thus could incur costs under the rule. Because the number of
small business dental offices that process amalgam is only 259 offices less than the total dental
offices (109,862), and cost-to-revenue impacts above the thresholds are located in the lower
revenue ranges, there is no difference between the cost-to-revenue analysis performed for all
dental offices and that performed for small entities.
To assess the potential for significant impact on these small businesses, EPA relied on the
method of the cost-to-revenue impact analysis as presented in Section 10.3.1.1, which used one
and three percent of revenue thresholds as impact measures. As described in that section, EPA
performed this analysis on two bases:
• Excluding the baseline set-aside offices from the cost-to-revenue analysis.
• Including the baseline set-aside offices in the cost-to-revenue analysis.
Table 10-18 summarizes the results for small entities from this analysis.
Table 10-18. Cost-to-Revenue Impact Analysis for Small Entities
Offices with Cost Exceeding 1 Percent of Revenue
Technology-
In-Place
No-Tech-
in-Place
Total
Percentage
Offices with Cost Exceeding 3 Percent of Revenue
Technology-
In-Place
No-Tech-
in-Place
Total
Percentage
Excluding Baseline Set-Aside Offices from Analysis
33
474
507
0.5%
0
0
0
0.0%
Including Baseline Set-Aside Offices in Analysis
243
722
965
0.9%
51
169
221
0.2%
Results are the same for both the ADA National and Colorado distributions of chairs by office.
Percentages of affected offices are calculated as a fraction of total small business offices estimated to incur costs
under the proposed Dental Amalgam Rule.
Source: U.S. EPA, 201 Ic.
As shown in Table 10-18, with the baseline set-aside offices excluded from the analysis,
EPA estimates that 507 dental offices would incur costs exceeding one percent of revenue.34
These offices represent 0.5 percent of the small business offices estimated to incur costs under
the proposed Dental Amalgam Rule. EPA estimates that no small entities would incur costs
exceeding three percent of revenue for the proposed rule.
With the baseline set-aside offices included in the analysis, EPA estimates that 965 dental
offices would incur costs exceeding one percent of revenue. These offices represent 0.9 percent
of small business offices estimated to incur costs under the proposed Dental Amalgam Rule.
EPA estimates that 221 dental offices would incur costs exceeding three percent of revenue,
representing 0.2 percent of small business offices estimated to incur costs under the proposed
Dental Amalgam Rule.
From this analysis, given the very small percentage of small business dental offices
potentially incurring costs exceeding the one percent and three percent of revenue thresholds,
34
These findings do not vary by distribution of chairs by office.
10-28
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Section 10 - Economic Impacts for the Dental Industry
EPA estimates that the proposed Dental Amalgam Rule would not impose a significant impact
on a substantial number of small entities (SISNOSE).
10.6 REFERENCES
ADA. 2009. American Dental Association. An Economic Study of Expanded Duties of Dental
Auxiliaries in Colorado. Beazoglou, et al. Document Control Number (DCN) DA00149.
ADA. 2010a. Distribution of Dentists in the United States by Region and State, 2008. August.
DCN D AGO 123.
ADA. 2010b. 2009 Survey of Dental Practice: Income from the Private Practice of Dentistry.
DCNDA00141.
Census. 2007. U.S. Census Bureau. Economic Census: Firm and Establishment Size. DCN
DA00142.
Georgetown University, 2003. Safety Net Dental Clinic Manual. National Maternal and Child
Oral Health Resource Center. DCN DA00151 and DCN DA00154.
Pimpare, Justin. 2012. Dentists Who Certify They Neither Place Nor Remove Amalgam.
Memorandum. U.S. EPA Region 1. 25 January. DCN DA00161.
U.S. EPA. 2000. Economic, Environmental, and Benefits Analysis of the Proposed Metal
Products and Machinery Rule (EPA-821-B-00-008). Office of Water. December. DCN
DA00251.
U.S. EPA. 201 la. EPA Analysis: Part 441 Option Cost Calculations. MS Excel™ file. Office of
Water. Washington, DC. DCNDA00146.
U.S. EPA. 20 lib. Information Collection Request: National Pretreatment Program OMB
Control No. 2040-0009, EPA ICRNo. 0002.14 (Draft). Office of Wastewater
Management. March. DCNDA00144.
U.S. EPA. 201 Ic. Economic Analysis for the Dental Amalgam Rule. MS Excel™ file. Office of
Water. Washington, DC. DCNDA00145.
U.S. EPA. 201 Id. Technical Support Document for the 2010 Effluent Guidelines Program Plan.
EPA-820-R-10-021. Office of Water. Washington, DC. DCNDA00225.
Vandeven, J., and S. McGinnis. 2005. An Assessment of Mercury in the Form of Amalgam in
Dental Wastewater in the United States."Water, Air and Soil Pollution 164:349-366.
DCN D AGO 163.
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Section 11 - Pollutant Reduction Estimates
SECTION 11
POLLUTANT REDUCTION ESTIMATES
The proposed rule establishes a pretreatment standard that would require removal of at
least 99.0 percent of total mercury from amalgam discharges and best management practices
(BMPs). EPA's pollutant reduction methodology assumes dental offices would use the required
BMPs in combination with 2008 ISO 11143 amalgam separators, the proposed technology basis,
to comply with the proposed rule.
EPA does not have office-specific discharge data for the approximately 110,000 dental
offices potentially subject to the proposed rule. Instead, EPA has modeled the discharges of
mercury and other metals based on nationwide estimates of amalgam fillings placed
(restorations) and removals and did not calculate the pollutant loadings and reductions on a per
office basis. Rather, EPA calculated average mercury (and other pollutant) loadings by dividing
the pollutant loadings from the total number of annual procedures by the total number of dentists
performing these procedures.35 This is the same approach and data that EPA presented in its
Health Services Industry Detailed Study (U.S. EPA, 2008). EPA did not receive comments on
this part of the detailed study that would cause EPA to reconsider its approach, and therefore,
EPA did not change the overall methodology. The following sections describe the methodology
in more detail.
11.1 NATIONAL ESTIMATE OF ANNUAL POLLUTANT LOADINGS FROM DENTAL OFFICES
This section describes the methodology used to estimate national baseline pollutant
loadings generated at dental offices and discharged to publicly owned treatment works (POTWs)
and to surface waters.
11.1.1 National Estimate of Annual Mercury in Dental Office Wastewater
First, EPA estimated the amount of mercury potentially generated nationwide through
amalgam restorations. EPA's main source of the data underlying all of the estimates related to
restorations is Vandeven and McGinnis, 2005. EPA estimated that 71 million restorations are
performed at dental offices annually and that these restorations require one amalgam capsule per
restoration. Each amalgam capsule contains 450 milligrams (mg) of mercury and, on average,
dentists use 75 percent of the capsule for the filling. The 25 percent of mercury remaining in the
capsule is discarded as gray bag waste. Therefore, approximately 340 mg of mercury (75 percent
of the capsule) are used per filling. Further, 9 percent of those 340 mg (31 mg) is discharged to
the dental office wastewater as carvings and filings or other waste (Vandeven and McGinnis,
2005). From these data, EPA estimated that dental offices generate a total of 2.4 tons of mercury
nationwide36 in their wastewaters from restorations (U.S. EPA, 2011). Table 11-1 presents how
mercury waste is generated at dental offices during amalgam restorations.
35 Because this approach is based on the number of dentists, it includes those dentists both at offices and institutional
facilities.
36 71 million restorations times 31 mg per filling.
11-1
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Section 11 - Pollutant Reduction Estimates
Table 11-1. Mercury Waste Generation from the Restoration of Dental Amalgam
Process
Description
Amalgam
Restoration
71 million
procedures
per year
Total Mercury
450 milligrams
(mg) per
capsule
Mercury used for
Filling
340 mg
(75% of total
mercury)
Waste Mercury
31mg(9%of
filling mercury) -
carvings and filings
during procedure
1 10 mg (25% of total mercury) remains
in capsule
Waste Disposal
Rinsed into wastewater drain
2.4 tons per year from all procedures
Discarded as gray bag waste
Sources: U.S. EPA, 2011; Vandeven and McGinnis, 2005.
Second, EPA modeled mercury generation from amalgam removals. As with 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 that approximately 97
million amalgam removals occur each year (U.S. EPA, 2011). An average of 300 mg mercury is
removed from each filling (Vandeven and McGinnis, 2005). EPA assumed that 90 percent of the
removed filling (270 mg mercury) becomes part of the dental office wastewater, and the other 10
percent is handled as dry waste and/or gray bagged. Thus, EPA estimated dental offices generate
29 tons of mercury in their wastewaters from amalgam filling removals each year37 (U.S. EPA,
2011). Table 11-2 presents how mercury waste is generated at dental offices during amalgam
removals.
Table 11-2. Mercury Waste Generation from the Removal of Dental Amalgam
Process
Description
Amalgam
Removal
97 million
procedures
per year
Total Mercury
300 milligrams
(mg) per
removed filling
Waste Mercury
270 mg
(90% of total mercury)
30 mg (10% of total mercury)
Waste Disposal
Rinsed into wastewater drain
29 tons per year from all procedures
Dry waste disposal/gray bag waste
Sources: U.S. EPA, 2011; Vandeven and McGinnis, 2005.
Summing the total mercury loading from the annual number of restorations and filling
removals, EPA estimated dental offices generate 31.4 tons of mercury annually as part of dental
office wastewaters, see Table 11-3.
57 97 million amalgam filling removals times 270 mg per removal.
11-2
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Section 11 - Pollutant Reduction Estimates
Table 11-3. Annual Untreated Mercury Generation from the Restoration and
Removal of Dental Amalgam
Description
Amalgam
Restorations
Amalgam
Removals
TOTAL
Number of
Procedures
71 million
97 million
Mercury in
Dental Office
Wastewater per
Procedure
3 1 milligrams
(mg)
270 mg
Mercury in Dental
Office Wastewater
(Untreated)
2.4 tons (U.S.)
29 tons (U.S.)
31.4 tons
Notes
Estimate mercury entering wastewater
based on number of restoration
procedures. Amalgam capsule contains
450 mg of mercury. Assume 75 percent
of the capsule is used for restoration (340
mg). During placement, 9 percent of the
mercury (3 1 mg) is rinsed into
wastewater drain as carvings or filings.
Estimate by number of general dentists
and specialists who perform removals
and average number of removals per
dentist and per specialist. Assume 90
percent of mercury removed (270 mg) is
part of the dental office wastewater.
Sources: U.S. EPA, 2011a; Vandeven and McGinnis, 2005.
11.1.2 National Estimate of Annual Baseline Mercury Discharges from Dental Offices
to POTWs
EPA estimated that within the 109,972 dental offices potentially subject to the proposed
Dental Amalgam Rule, 13,102 offices do not place or remove amalgam and therefore do not
generate amalgam wastewater (Section 10.1.2). Therefore, the remaining 96,870 offices
collectively generate 31.4 tons of mercury in their wastewaters. This equates to 0.65 pounds per
office. However, as explained earlier, these dental offices currently employ treatment
technologies that will reduce this mercury prior to discharge. EPA assumed the following with
respect to current technologies in place:
• Twenty percent use chair-side traps only (Vandeven and McGinnis, 2005): 19,374
dental offices.
• 44,461 dental offices use amalgam separators (U.S. EPA, 201 1).
• The remaining 33,035 dental offices use chair-side traps and vacuum filters.
The mercury removal efficiency of the chair-side trap is 68 percent, and the mercury
removal efficiency of the chair-side trap plus vacuum filter is 78 percent (Vandeven and
McGinnis, 2005). After accounting for mercury reductions achieved through existing chair-side
traps, vacuum filters, and amalgam separators, as appropriate, EPA estimated that the
approximately 52,000 dental offices without amalgam separators collectively discharge a total of
4.4 tons of mercury to POTWs per year. The approximately 44,000 dental offices with amalgam
separators collectively discharge approximately 63 pounds of mercury to POTWs per year. Thus,
EPA calculated the current nationwide annual baseline loading of mercury discharged to POTWs
-------
Section 11 - Pollutant Reduction Estimates
from dental offices to be 4.4 tons, out of a total of the 31.4 tons originally generated (U.S. EPA,
2011).
Table 11-4 summarizes the use and mercury removal efficiencies of wastewater treatment
technologies at dental offices.
Table 11-4. Dental Office Use and Mercury Removal Efficiency by Treatment Technology
Treatment Technology
Chair-Side Traps Only
Chair-Side Traps and Vacuum Filter Only
Amalgam Separator
Total
Number of Dental Offices
19,374
33,035
44,461
96,870
Removal Efficiency for
Total Mercury
68%
78%
99.0%
-
Sources: U.S. EPA, 2011; Vandeven and McGinnis, 2005.
11.1.3 National Estimate of Annual Non-Mercury Amalgam Metals in Dental Offices
Wastewater
In addition to mercury, dental amalgam contains other metal constituents. EPA estimated
pollutant loadings for four other metals contained in dental amalgam: silver, tin, copper, and
zinc. The composition of amalgam is approximately 49 percent mercury, 35 percent silver, 9
percent tin, 6 percent copper, and a small amount of zinc (Massachusetts Water Resources
Authority, 2001). Using the mercury generation estimates in Section 11.1.1, EPA estimated the
generation of metal waste in dental office wastewater (see Table 11-5).
Table 11-5. Calculation of Annual Untreated Non-Mercury Metal Generation from the
Restoration and Removal of Dental Amalgam
Description
Amalgam
Restorations
Amalgam
Removals
Pollutant in
Dental Office
Wastewater
Mercury
Non-Mercury
Metals
Mercury
Non-Mercury
Metals
Per Procedure
31 milligrams
(mg)
32 mg
270 mg
281 mg
Annual Loading
(Untreated)
2.4 tons (U.S.)
2.5 tons (U.S.)
29 tons (U.S.)
30 tons (U.S.)
Notes
Estimate non-mercury metals entering
wastewater based on ratio of amalgam
composition: 49 percent mercury and 5 1
percent non-mercury metals.
Sources: U.S. EPA, 2011.
11.1.4 National Estimate of Annual Baseline Discharges of Non-Mercury Amalgam Metals
from Dental Offices to POTWs
As with mercury pollutant loadings, EPA assumed chair-side traps and vacuum filters
will result in 68 and 78 percent collection of all amalgam metals, respectively. EPA also
assumed a 99.0 percent removal of all amalgam metals at offices with amalgam separators in
place. Using the same methodology as described for mercury in Section 11.1.2 to calculate
11-4
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Section 11 - Pollutant Reduction Estimates
baseline pollutant loadings, EPA estimated the non-mercury metal mass loading generated by
amalgam restorations as 2.5 tons per year. EPA similarly estimated the non-mercury metal mass
loading generated by amalgam removals as 30 tons per year. After accounting for existing
technologies at dental offices, EPA calculated the current nationwide annual baseline loading of
non-mercury metals discharged to POTWs from dental offices to be 4.6 tons, out of a total of
32.5 tons originally generated (U.S. EPA, 2011).
11.1.5 Total Annual Baseline Discharges to POTWs
After accounting for existing technologies at dental offices, EPA estimated dental offices
collectively discharge 4.4 tons of mercury and 4.6 tons of additional metals to POTWs per year
for a total discharge to POTWs of 9.0 tons annually.
11.2 NATIONAL ESTIMATE OF ANNUAL POLLUTANT REDUCTIONS TO POTWs ASSOCIATED
WITH THE PROPOSED DENTAL AMALGAM RULE
EPA estimated that the 52,409 dental offices (19,374 dental offices with chair-side traps
only and the 33,035 dental offices with chair-side traps and vacuum filters only) would install
2008 ISO 11143 certified amalgam separators with a removal efficiency of at least 99.0 percent
as a result of the proposed Dental Amalgam Rule. The combination of chair-side traps, vacuum
filters and separators would then achieve 99.8 percent removal of total solids (i.e., all metals)
from the dental wastewater (U.S. EPA, 2011). This would result in reduction of total mercury
discharges to POTWs by 4.3 tons. Because dissolved mercury accounts for much less than 1
percent of total mercury (Stone, 2004), and because amalgam separators are not effective in
removing dissolved mercury, EPA assumed the dissolved mercury contribution and associated
reduction in loadings to be negligible.
Similarly, EPA estimated a reduction of non-mercury metal (i.e., silver, tin, copper, and
zinc) discharges to POTWs of approximately 4.5 tons. Again, EPA assumes the dissolved metal
content to be negligible.
Accordingly, the proposed Dental Amalgam Rule 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.
11.3 NATIONAL ESTIMATE OF ANNUAL POLLUTANT REDUCTIONS TO SURFACE WATERS
ASSOCIATED WITH THE PROPOSED DENTAL AMALGAM RULE
In order to evaluate final discharges of mercury (and other metals) to waters of the United
States by POTWs, EPA used its 50 POTW Study to calculate POTW removals of each metal. As
detailed above, at baseline and prior to implementation of the proposed rule, EPA estimated that,
collectively, dental offices discharge 4.4 tons38 of dental mercury annually to POTWs. Based on
the 50 POTW Study, EPA estimates that POTWs remove 90 percent of the 4.4 tons mercury
from the wastewater. Thus, POTWs collectively discharge 880 pounds of dental mercury to
surface waters annually.
38 This may be a conservative assumption, particularly where sewers are designed for overflows (as is the case for
combined sewers), or where sewers have overflows as a result of improper maintenance or accidents and natural
disasters (e.g., floods or earthquakes).
11-5
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Section 11 - Pollutant Reduction Estimates
Under the proposed Dental Amalgam Rule, over 98 percent of mercury solids currently
discharged annually to POTWs will be removed by the installation of amalgam separators. The
POTWs then further remove 90 percent of total mercury from the wastewater. This reduces the
total amount of dental mercury discharged from POTWs nationwide to surface water to 14
pounds annually. In other words, discharges of mercury to waters of the United States are
expected to be reduced by 860 pounds per year39 as a result of the proposed rule.
Based on the 50 POTW Study (U.S. EPA, 1982), POTWs remove the following from
wastewater prior to discharge:
88 percent of total silver;
79 percent of total tin;
84 percent of total copper; and
79 percent of total zinc.
At baseline, EPA estimates that dental offices discharge over 9,000 pounds of non-
mercury amalgam metals to POTWs annually. After treatment at the POTW, POTWs
collectively discharge 1,280 pounds of non-mercury amalgam metals to surface waters annually.
Under the proposed Dental Amalgam Rule, the non-mercury amalgam metal discharges from
POTWs to surface waters will be approximately 20 pounds, a reduction of 1,260 pounds. This
results in the total reduction of amalgam metals (mercury and non-mercury) to waters of the
United States by an estimated 2,120 pounds (U.S. EPA, 2011).
11.4 REFERENCES
Massachusetts Water Resources Authority. 2001. Amalgam Composition in Typical Dental
Fillings (figure). Document Control Number (DCN) DA00131.
Stone, M.E. 2004. The Effect of Amalgam Separators on Mercury Loading to Wastewater
Treatment Plants. Journal of the California Dental Association, 32(7):593-600. DCN
DA00018.
U.S. EPA. 1982. Effluent Guidelines Division. Fate of Priority Pollutants in Publicly Owned
Treatment Works. EPA 440/1-82/303. Washington, DC. (September). DCNDA00244.
U.S. EPA. 2008. Health Services Industry Detailed Study: Dental Amalgam. EPA-821-R-08-014.
August. DCN DA00057.
U.S. EPA. 2011. EPA Analysis: Part 441 Option Cost Calculations. MS Excel™ file. Office of
Water. Washington, DC. DCNDA00146.
Vandeven, J., and S. McGinnis. 2005. An Assessment of Mercury in the Form of Amalgam in
Dental Wastewater in the United States. Water, Air, and Soil Pollution, 164:349-366.
DCN D AGO 163.
39 Dissolved mercury accounts for a portion of surface water discharges, because amalgam separators do not remove
dissolved mercury.
11-6
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Section 12 - Cost-Effectiveness Analysis
SECTION 12
COST-EFFECTIVENESS ANALYSIS
EPA traditionally defines cost-effectiveness as the total incremental annualized cost of a
pollution control option per total incremental toxic pound-equivalent (i.e., pound of pollutant
adjusted for relative toxicity) removed by that control option. EPA uses the cost-effectiveness
analysis primarily in comparing the removal efficiency of regulatory options under consideration
for a rulemaking. A secondary use is to compare the cost-effectiveness of the proposed option to
those for effluent limitation guidelines and standards (ELGs) for other industries. This definition
includes the concepts discussed in this section.
12.1 TOTAL INCREMENTAL ANNUALIZED COMPLIANCE COSTS
The cost-effectiveness analysis uses the estimated total annual costs of complying with
the proposed rule. As described in Section 10.3, EPA developed two estimates of incremental
costs, reflecting different distributions of numbers of chairs in dental offices. EPA adjusts the
compliance costs to 1981 dollars to allow for comparison with cost-effectiveness values for other
promulgated regulations for different industries. For this proposal, EPA adjusted the value using
the Bureau of Economic Analysis GDP Implicit Price Deflators.40 EPA calculates this adjustment
factor as follows:
Adjustment factor = (1981$) - (2010$) = 52.270 - 110.992 = 0.47093
Table 12-1 shows the estimated annualized compliance costs converted to 1981 dollars.
Table 12-1. Annualized Compliance Costs (Million $)
Dental Office
Distribution Data Source
ADA Colorado Survey
ADA National Survey
Annualized Compliance
Costs At Promulgation
Year (million 2010$)
$43.6
$48.5
GDP Deflator
to Convert
2010$ to 1981$
0.47
Annualized
Compliance Costs
(million 1981$)
$21
$23
Source: U.S. EPA, 201 la.
12.2 Toxic WEIGHTING FACTORS
Because each pollutant differs in its potential harmful effects on human and aquatic life,
EPA uses a toxic weighting factor (TWF) specific to each pollutant to calculate a toxicity-
normalized pollutant removal value for use in the cost-effectiveness analysis.41 EPA derives toxic
weighting factors for each pollutant using chronic aquatic life criteria (or toxic effect levels) and
human health criteria (or toxic effect levels) established for the consumption offish. Table 12-2
lists the TWFs for the pollutants found in dental discharges.
40 EPA typically uses the Engineering News Record Construction Cost Index. However, this approach is not
appropriate for this proposal because the technology option does not require construction.
41 See U.S. EPA, 201 Ib for details on toxic weighting factors.
12-1
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Section 12 - Cost-Effectiveness Analysis
Table 12-2. Toxic Weighting Factors for Pollutants in Dental
Amalgam
Pollutant
Total mercury
Silver
Tin
Copper
Zinc
Toxic Weighting Factor
117.12
16.47
0.30
0.63
0.05
12.3
CALCULATION OF ANNUAL TOTAL INCREMENTAL POUND-EQUIVALENTS REMOVED TO
SURFACE WATERS
EPA estimated the annual reduction in pollutant loadings nationwide to waters of the
United States associated with the proposed rule for each pollutant identified in dental amalgam.
Because this proposed rule is for indirect discharges, this estimate appropriately accounts for
discharge reductions that occur at the publicly owned treatment works (POTW). See Section 10
of this document for further information on how loadings were calculated. EPA adjusts the
reductions in a pollutant's discharges for an option, or pollutant removals, for toxicity by
multiplying the estimated removal quantity for each pollutant by its TWF. EPA refers to these
adjusted removals as toxic weighted pound-equivalents (TWPEs). EPA summed the TWPE
reductions for each pollutant to estimate the total annual incremental pound-equivalent
reductions for the proposed rule. Table 12-3 presents the estimate of individual and total annual
incremental pound-equivalent removals from surface waters for the proposed rule.
Table 12-3. Total Incremental Pound-Equivalents Removed
from Surface Water Discharges3
Pollutant
Total mercury
Silver
Tin
Copper
Zinc
Total
Incremental Removals
from Baseline (Ibs/yr)
863
722
331
167
37
Toxic Weighting Factors
117.12
16.47
0.30
0.63
0.05
Incremental Removals
from Baseline (Ib-eq/yr)
101,048
11,896
100
106
2
113,152
Source: U.S. EPA, 20lie.
a - Numbers shown are rounded; multiplying values across the first two columns will not exactly equal the value in the last
column
12.4 COST-EFFECTIVENESS RESULTS
Table 12-4 presents the cost-effectiveness data and results. The cost-effectiveness value
for the proposed rule is $181-$201/lb-eq ($1981).
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Section 12 - Cost-Effectiveness Analysis
Table 12-4. PSES Cost-Effectiveness Analysis
Dental Office Distribution
Data Source
ADA National Survey
ADA Colorado Survey
Pre-Tax Total
Annualized Costs
($1981)
$23,000,000
$21,000,000
Removals (Ibs-eq)
113,152
113,152
Average Cost-
Effectiveness ($1981)
$201
$181
Source: U.S. EPA, 2011 a.
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. For the proposed Dental Amalgam Rule, it 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
proposed rule has a cost-effectiveness ratio of $181 to $201 per Ib-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
found that PSES cost effectiveness ranges from approximately $1 per Ib-equivalent (Inorganic
Chemicals) to $380 per Ib-equivalent (Transportation Equipment Cleaning) in 1981 dollars.
12.5 REFERENCES
U.S. EPA. 201 la. Economic Analysis for the Dental Amalgam Rule. MS Excel™ file. Office of
Water. Washington, DC. Document Control Number (DCN) DA00145.
U.S. EPA. 201 Ib. Technical Support Document for the 2010 Effluent Guidelines Program Plan.
EPA-820-R-10-021. Office of Water. Washington, DC. DCNDA00225.
U.S. EPA. 201 Ic. EPA Analysis: Part 441 Option Cost Calculations. MS Excel™ file. Office of
Water. Washington, DC. DCNDA00146.
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Section 13 -Environmental Impacts of Dental Mercury Discharges
SECTION 13
ENVIRONMENTAL IMPACTS OF DENTAL MERCURY
DISCHARGES
Aside from mercury, other constituents of dental amalgam include the metals silver, tin,
copper, zinc, indium, and palladium. Of the dental amalgam constituents, mercury is of greatest
concern to human health because it is a persistent, bioaccumulative, toxic chemical and
biomagnifies in aquatic food chains. For wastewater mercury discharges, the major route for
human exposure to mercury discharged in wastewater is the consumption of mercury-
contaminated fish.
13.1 MERCURY IN DENTAL WASTEWATER
Mercury discharged in dental wastewater is present in many forms, including elemental
mercury bound to amalgam particulate, inorganic (ionic) mercury, elemental mercury, and
organic mercury (methylmercury, or MeHg) (Stone et al., 2002). Table 13-1 presents the mean
concentrations of mercury species measured in wastewater samples collected at the chair. Nearly
all (>99.6 percent) of dental mercury discharges are in solid form (elemental mercury bound to
amalgam particulate).
Table 13-1. Mean Concentrations of Mercury Species in Dental Wastewater
Mercury Form
MeHg (methylmercury)
HgO (unbound elemental mercury)
Hg+2 (ionic mercury)
HgO (elemental mercury bound to
amalgam particulate)
Measured Concentration
277.74 nanograms/liter (ppt)
24.06 micrograms/liter (ppb)
54 micrograms/liter (ppb)
21.360 milligrams/liter (ppm)
Percent of Total Mercury
0.0013%
0.112%
0.252%
99.6%
Source: Stone, 2004.
While dissolved mercury (MeHg, unbound HgO, Hg+2), makes up less than one percent
of the total mercury in dental wastewater, there is increasing interest in the causes of dissolution
and the extent to which dissolved mercury is present in dental wastewater. Dissolved mercury is
a concern because elemental and ionic mercury can be converted to form additional
methylmercury by bacteria, such as Desulfobacteraceae and Desulfovibrionaceae, which are
present in wastewater (ACS, 2008). Methylmercury is particularly toxic to humans due to its
ability to bioaccumulate in fish. When humans consume methylmercury, it targets the nervous
system and can hinder a person's ability to walk, talk, see, and hear. Extreme cases of
methylmercury poisoning can result in coma or death (WIDNR, 1997).
Researchers have detected concentrations of methylmercury in dental wastewater that are
orders of magnitude higher than background methylmercury concentrations measured in
environmental samples from open oceans, lakes, and rainfall. Concentrations of methylmercury
in dental wastewater ranged from 0.90 to 26.77 milligrams per liter (mg/L). Such dissolved
mercury concentrations can be high enough to violate local mercury discharge limits (Stone,
2004). In comparison, concentrations in environmental samples have ranged from 0.05 to 10.0
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Section 13 -Environmental Impacts of Dental Mercury Discharges
nanograms per liter (ng/L) (Stone et al., 2002). Researchers have concluded that sulfate-reducing
bacteria are responsible for the presence of methylmercury in dental wastewater; however, it is
not clear whether methylation occurs in the patient's mouth or in the discharge stream (ACS,
2008).
13.2 DENTAL MERCURY FATE AND TRANSPORT
The form of mercury discharged from dental practices is important to publicly owned
treatment works (POTWs) because it can affect their ability to remove mercury from influent
wastewater. Solid mercury particles will likely settle out of solution and adsorb to the wastewater
treatment sludge. However, dissolved mercury can pass through treatment operations and enter
surface waters. For the pass-through analysis conducted as part of this rulemaking (see Section
5.3), EPA used a 90 percent removal rate for total mercury.
POTWs manage their wastewater treatment sludge (biosolids) through beneficial reuse
(60 percent) and via disposal (40 percent). Disposed biosolids are typically incinerated (22
percent of all biosolids) or disposed of in a landfill (18 percent of all biosolids) (U.S. EPA,
1999). Mercury is a relatively volatile metal that can be converted to a gas by incineration and
emitted to the atmosphere. Once in the atmosphere, mercury is deposited into lakes and streams
by rainfall. (WI DNR, 1997). In contrast, solid mercury particles disposed of in a landfill are
unlikely to be released into the environment.
13.3 ENVIRONMENTAL ASSESSMENT
EPA conducted a literature review concerning potential environmental impacts associated
with mercury in dental amalgam discharged to surface water by POTWs (U.S. EPA, 201 la).
Studies indicate that dental offices are a primary source of mercury entering POTWs. Through
treatment, POTWs remove approximately 90 percent of dental mercury from wastewater and
transfer it to sewage sludge. The 10 percent of dental mercury not removed by POTW treatment
is discharged to surface water.
13.3.1 Mercury in Surface Water Discharges
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 the aquatic food chains, as larger fish
eat smaller fish. This accumulation can be profound, with biomagnifications of 100,000 times
from algae to top predators having been documented (Chin, et al., 2000).
The neurological effects of eating fish contaminated with methylmercury are well
documented (WI DNR, 1997). 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 in wild populations offish, birds, and mammals in
many areas of the United States (WI DNR, 1997). A plausible link has been identified between
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Section 13 -Environmental Impacts of Dental Mercury Discharges
anthropogenic sources of mercury (e.g., coal combustion) in the United States and
methylmercury in fish. However, methylmercury in fish can also come from existing background
concentrations of mercury, which may consist of mercury from natural sources, mercury re-
emitted from the oceans or soils, or mercury deposited in the United States from sources in other
countries. Current scientific understanding of mercury's environmental fate and transport does
not allow quantification of how much of the methylmercury in fish consumed by the U.S.
population is contributed by U.S. emissions, nor how much derives from natural mercury
sources, or for that matter, from dental discharges.
EPA was unable to assess the 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.
13.3.2 Mercury in Biosolids
The Clean Water Act regulations at 40 CFR 503, Standards for Use and Disposal of
Sewage Sludge, 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 percent, or 6.7 billion pounds, are treated to produce biosolids for beneficial use as a soil
amendment and applied to about 0.1 percent of agricultural lands in the United States (National
Research Council, 2002). EPA estimates that approximately 4,800 pounds of dental mercury
enters the environment as land-applied biosolids. Nevertheless, the mercury content of land
applied biosolids has been documented to be well below the risk-based pollutant concentration
limits set by 40 CFR 503.
Approximately 18 percent, 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 (U.S. EPA, 1999). EPA estimates that approximately 1,400 pounds per year of dental
mercury are contained in surface disposed sewage sludge. Pollutant discharge limits and
monitoring requirements for surface disposed sewage sludge mono-fills are set by 40 CFR 503
and by 40 CFR 258 for municipal landfills.
The remaining 22 percent, or 2.5 billion pounds, of sewage sludge generated annually by
POTWs is incinerated (U.S. EPA, 1999). Incineration of sewage sludge emits an estimated 35
pounds of dental mercury to the atmosphere annually, of which approximately 11.5 pounds are
deposited within the conterminous United States (U.S. EPA, 1997; U.S. EPA, 2005a; U.S. EPA,
2005b; and U.S. EPA, 2009). 40 CFR 503 limits the quantity of mercury and other toxic metals
allowed per unit amount of sewage sludge prior to incineration. Concentrations of mercury
emitted from sewage sludge incinerators must meet the National Emissions Standards for
Hazardous Air Pollutants requirements in subpart E of 40 CFR 61.
13.3.3 Environmental Benefits of the Proposed Dental Amalgam Rule
EPA did not perform an environmental benefits analysis of the proposed rule due to
insufficient data about the aquatic fate and transport of dental mercury discharged by POTWs.
1O O
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Section 13 -Environmental Impacts of Dental Mercury Discharges
However, EPA was able to assess the qualitative environmental benefits based on existing
information. Studies have shown that decreased point source discharges of mercury to surface
water result in lower methylmercury concentrations in fish. Moreover, several studies have
quantified economic benefits from improved human health and ecological conditions resulting
from lower fish concentrations of methylmercury (U.S. EPA, 201 la). The proposed requirement
for installation of amalgam separators with 99.0 percent mercury removal efficiency will
produce human health and ecological benefits by reducing the estimated annual nationwide
POTW discharges of dental mercury to surface waters from 880 pounds to 14 pounds (U.S. EPA,
201 Ib). In addition, the decreased discharges to POTWs will result in a decrease of mercury in
biosolids.
13.4 REFERENCES
ACS (American Chemical Society). 2008. Dental Offices Contribute to Methylmercury Burden:
Bacteria That Methylate Mercury Thrive in Wastewater Found Downstream from Dental
Traps. Environmental Science & Technology Online News. March 12. Document Control
Number (DCN) DA00201.
Chin, G., J. Chong, A. Kluczewska, A. Lau, S. Gorjy, and M. Tennant. 2000. The Environmental
Effects of Dental Amalgam. Australian Dental Journal 45: 246-249. DCN DA00312.
National Research Council (NRC). 2002. Biosolids Applied to Land: Advancing Standards and
Practices. July. Division on Earth and Life Sciences. DCN DA00257.
Stone, M.E., et al. 2002. Determination of Methyl Mercury in Dental-Unit Wastewater. Dental
Materials 19:675-679. DCNDA00173.
Stone, M.E. 2004. The Effect of Amalgam Separators on Mercury Loading to Wastewater
Treatment Plants. Journal of the California Dental Association, 32(7):593-600. DCN
DA00018.
U.S. EPA. 1999. Biosolids Generation, Use, and Disposal in the United States. Office of Solid
Waste. EPA 530-R-99-009. September.
http://www.epa.gov/osw/conserve/rrr/composting/pubs/biosolid.pdf DCN DA00303.
U.S. EPA. 1997. Mercury Study Report to Congress. Volume VII: Characterization of Human
Health and Wildlife Risks from Mercury Exposure in the United States. EPA-452/R-97-
009. DCN DA00256.
U.S. EPA. 2005a. Revision of December 2000 Regulatory Finding on the Emissions of
Hazardous Air Pollutants from Electric Utility Steam Generating Units and the Removal
of Coal- and Oil-Fired Electric Utility Steam Generating Units From the Section 112(c)
List; Final Rule. 40 CFRPart 63. DCNDA00319.
U.S. EPA. 2005b. Regulatory Impact Analysis of the Clean Air Mercury Rule: Final Report.
Office of Air Quality Standards and Planning. EPA-452/R-05-003. DCN DA00283.
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Section 13 -Environmental Impacts of Dental Mercury Discharges
U.S. EPA. 2009. Targeted National Sewage Sludge Survey: Sampling and Analysis Technical
Report. DCN DA00299.
U.S. EPA. 201 la. Literature Review of the Impacts of Mercury from Dental Amalgam in
Wastewater. Office of Water. Washington, DC. DCN DAGO 148.
U.S. EPA. 201 Ib. EPA Analysis: Part 441 Option Cost Calculations. MS Excel™ file. Office of
Water. Washington, DC. DCNDA00146.
WIDNR (Wisconsin Department of Natural Resources). 1997. Wisconsin Mercury Sourcebook.
DCN DA00202.
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Section 14 - Non-Water-Quality Impacts
SECTION 14
NON-WATER-QUALITY IMPACTS
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 limitation
guidelines and standards (ELGs). To comply with these requirements, EPA considered the
potential impact of amalgam separators and best management practices (BMPs) on energy
consumption, air pollution, and solid waste generation. EPA anticipates that the proposed Dental
Amalgam Rule will produce minimal non-water-quality impacts. The Administrator has
determined that these very minimal impacts are acceptable.
14.1 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. As described in Section 5, the wastewater
treatment system at dental offices include the chair-side trap, vacuum pump with filter, and
amalgam separator. Dental vacuum systems operate at a typical vacuum level of six to eight
inches mercury and a typical airflow of seven standard cubic feet per minute per chair-side high
volume inlet. Excess amalgam from new fillings, as well as amalgam from removed restorations,
is rinsed into the chair-side drain. Amalgam separators typically use sedimentation, either alone
or in conjunction with filtration, to remove essentially all of the excess amalgam from the
wastewater. 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 the proposed rule did not include 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 (McManus and
Fan, 2003). 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, EPA concluded there will be no
significant non-water-quality impacts associated with the energy requirements for the proposed
rule.
14.2 SOLID WASTE GENERATION
In the absence of amalgam separators, a portion of the amalgam rinsed into chair-side
drains is collected by chair-side traps and a portion of the amalgam suctioned into the vacuum
line is collected by vacuum pump filters. The remainder carried by wastewater to the publicly
owned treatment works (POTW), where approximately 90 percent is removed from the
wastewater into the POTW sludge; the sludge may be land applied, disposed of in landfills or
mono-fills, or incinerated. The proposed rule is expected to increase the use of amalgam
14-1
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Section 14 - Non-Water-Quality Impacts
separators nationwide—EPA expects over 50,000 dental offices to install amalgam separators to
comply with the proposed rule (see Table 10-2). Currently, just under 45,000 dental offices have
separators installed (see Table 10-2). EPA expects the collected amalgam that is no longer
discharged to the POTW will be recycled via the spent separator canisters. The operation and
maintenance requirements associated with the amalgam separator compliance option will
promote recycling as the primary means of amalgam waste management. EPA expects the
proposed rule will not create additional solid waste, but will instead change 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 concluded that there will be a
reduction in non-water-quality impacts associated with solid waste generation as a result of the
proposed rule.
14.3 AIR EMISSIONS
While unbound mercury is highly volatile and can easily evaporate into the atmosphere,
an estimated 99.6 percent of dental mercury discharges are in solid bound form (i.e., elemental
mercury bound to amalgam particles) (Stone, 2004). Because nearly all dental mercury is bound
to solid particles, it likely will not volatilize to the atmosphere. Other metals contained in
mercury amalgams (silver, tin, copper, zinc, indium, and palladium) are much less volatile than
mercury and are also in solid bound form and are also not likely to volatilize to the atmosphere.
Therefore, EPA expects the proposed rule will not pose any increases in air pollution. EPA
concluded that there will be no significant non-water-quality impacts associated with air
emissions as a result of the proposed Dental Amalgam Rule.
14.4 REFERENCES
McManus, K.R., and P.L. Fan. 2003. Purchasing, Installing and Operating Dental Amalgam
Separators. Journal of the American Dental Association, 134:1054-1065. Document
Control Number (DCN) DA00162.
Stone, M.E. 2004. The Effect of Amalgam Separators on Mercury Loading to Wastewater
Treatment Plants. Journal of the California Dental Association, 32(7):593-600. DCN
DA00018.
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Section 15- Implementation
SECTION 15
IMPLEMENTATION
This section provides guidance to Control Authorities, such as publicly owned treatment
works (POTWs) in implementing Effluent Limitation Guidelines and Standards (ELGs) for the
Dental Category.
15.1 IMPLEMENTATION DEADLINE FOR EXISTING SOURCES
For existing sources, EPA proposes a compliance date of three years after the effective
date of the final rule. Section 307(b)(l) of the Clean Water Act (CWA) provides that 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 which are
small businesses. EPA expects that 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 the 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 best management practices (BMPs).
15.2 IMPLEMENTATION DEADLINE FOR 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." Table 15-1 presents the
implementation deadline for existing and new sources of dental amalgam discharges.
Table 15-1. Compliance Time for Dental Offices Potentially Subject to the Proposed Rule
Dental Office
Existing Office that Dischargers to
the Sewer
New Office that Discharges to the
Sewer
Requirement
Comply with PSES
Comply with PSNS
Deadline
Three years after the effective date
of any final rule.
When discharging begins.
15.3 REPORTING REQUIREMENTS
The following describes the steps a dental office would take to comply with the reporting
requirements associated with the proposed rule:
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Section 15- Implementation
1. A dental office (or facility) should determine if any of its operations are potentially
subject to the proposed rule.
i. Does the office discharge to a sewer or directly to a POTW? If not, the office in
not potentially subject to the proposed rule and does not have any obligations.
ii. Does the office exclusively practice one or more of the following dental
specialties: oral pathology, oral and maxillofacial radiology, oral and
maxillofacial surgery, orthodontics, periodontics, or prosthodontics? If yes, the
office is not potentially subject to the dental amalgam proposed rule.
2. If an office or facility is subject to the proposed rule, it should determine whether it
places or removes amalgam. If it does neither (except in limited emergency
circumstances), it would certify that to the Control Authority.
i. If an office or facility is subject to the proposed rule and places or removes
amalgam, it will need to comply with the general reporting requirements, which
include submission of two one-time reports: a 90-day compliance report and a
baseline monitoring report. The latter must be submitted within 180 days of the
effective date of any final rule. The office or facility will also have to submit an
annual certification.
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Section 16 - Updates to General Pretreatment Standards
(40 CFR 403)
SECTION 16
UPDATES TO GENERAL PRETREATMENT STANDARDS
(40 CFR 403)
In addition to the pretreatment standards for dental offices, EPA is proposing to amend
selected parts of the General Pretreatment Regulations to simplify oversight requirements for the
approximately 110,000 dental offices subject to this rule. When EPA promulgates categorical
industrial pretreatment standards, as defined in 40 CFR 403, affected dischargers are referred to
as Categorical Industrial Users (CIUs). The number of dental offices subject to the proposed
Dental Amalgam Rule is approximately 10 times the current number of CIUs. EPA recognized
that 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 to enforce
categorical pretreatment regulation on this industry would require an increase in available local,
state, and federal resources; and EPA does not expect such efforts to result in greater
environmental benefit. EPA is focusing 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, and achieving the projected pollutant reductions.
16.1 PROPOSED CHANGES TO THE GENERAL PRETREATMENT STANDARDS
EPA is proposing a new classification of CIU specifically tailored to the Dental Office
Effluent Limitation Guidelines and Standards rule: "Dental Industrial User" (DIU). EPA is
proposing that such users not be subject to the oversight requirements for Significant Industrial
Users, or SIUs (i.e., control mechanism issuance requirement, annual inspection, and sampling
requirements). Rather, EPA is proposing to allow Control Authorities to focus their oversight
efforts on those dental offices that fail to meet the compliance requirements of the DIU.
Under the proposed rule, a dental amalgam discharger is given the option of complying
with monitoring and reporting requirements in 40 CFR 441.60, which are tailored for dental
amalgam dischargers, in lieu of the otherwise applicable monitoring and reporting requirements
in 40 CFR 403. If a dental amalgam discharger complies with the special monitoring and
reporting requirements in Section 441.60, the remaining Part 403 requirements, and the
applicable pretreatment standards (PSES or PSNS), then the Control Authority may treat the
dental amalgam discharger as a DIU. The DIU must maintain compliance in order to retain its
DIU status.
If the dental office does not meet the requirements to be classified as a DIU, under the
proposed rule, the Control Authority would be required to classify the dental amalgam discharger
as an SIU as defined in 40 CFR 403.3(v). As an SIU, the Control Authority would be required to
conduct the oversight duties applicable to SIUs as described in 40 CFR 403.8(f).
EPA notes that the proposed changes to 40 CFR 403 to create the DIU classification are
changes that the Control Authority may adopt at its discretion. The changes to 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
16-1
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Section 16 - Updates to General Pretreatment Standards
(40 CFR 403)
POTW Pretreatment Program would need to incorporate the proposed changes into their legal
authority under 40 CFR 403.8(f)(l).
16.2 RESPONSIBILITIES OF THE CONTROL AUTHORITIES
As described in Section 1.2.3, the Control Authority (either the POTW or state/EPA
Region) is responsible for permitting, sampling, and inspecting industrial users that discharge to
POTWs. The proposed rule would require that a Control Authority evaluate, at least once per
year, whether an industrial user 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 to document their continued eligibility for DIU status.
16.2.1 Noncompliance
In accordance with 40 CFR 403.8(f)(2)(viii)(F), a dental amalgam discharger that is
classified as a DIU 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 inspects the office and finds the
office is not in compliance with 40 CFR 441.60. Upon discovery that a dental practice is not in
compliance with regulations at 40 CFR 441.60 (either reporting requirements, Part 403, or Part
441 PSES/PSNS requirements), the Control Authority must initiate enforcement in accordance
with its approved pretreatment program to return the dental amalgam discharger into compliance.
To continue to treat the dental office as a DIU, the Control Authority would need to verify and
find, through an inspection, that the dental amalgam discharger has returned to full compliance
with the criteria in Part 441.60. If, within 90 days, the Control Authority inspects, verifies, and
finds that the dental amalgam discharger has returned to full compliance with Part 441.60, then
the dental amalgam discharger would remain a DIU. The 90-day compliance deadline is
consistent with other portions of 40 CFR 403 (e.g., significant noncompliance, compliance report
deadlines, 90-day report after effective dates of categorical standards), and provides both the
dental amalgam discharger and Control Authority with an incentive to provide a timely return to
compliance. If the dental amalgam discharger has not returned to compliance within 90 days of
the initial noncompliance, the Control Authority could no longer treat the dental amalgam
discharger as a DIU, and the dental amalgam discharger would become an SIU. Control
Authorities are required to oversee SIUs, which includes inspecting and sampling 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)l)(iii) and (2)(v) and
403.10(f)(2)(i)).
16.2.2 Classification of Dental Offices as Non-Significant Categorical Industrial Users
(NSCIU)
EPA is not proposing to prohibit a Control Authority from finding that a dental office or
other facility may qualify as an NSCIU on an individual basis. State Approval Authorities and
POTW Control Authorities with the legal authority to implement the NSCIU classification may
find that one or more of their Dental Office CIUs may qualify as an NSCIU. 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
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Section 16 - Updates to General Pretreatment Standards
(40 CFR 403)
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.
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Section 17- Glossary And List of Acronyms
SECTION 17
GLOSSARY AND LIST OF ACRONYMS
ADA - American Dental Association.
AMSA - Association of Metropolitan Sewerage Agencies.
Amalgam - dental filling that is formed using liquid mercury and a metal powder mixture, often
supplied in capsules. Amalgam fillings contain approximately 49 percent mercury and a mixture
of metals—silver, tin, copper, and sometimes zinc, indium, or palladium - in the powder
mixture.
Amalgam Separator - treatment technology used at dental offices to remove solid particulates
from the wastewater.
BAT - The best available technology economically achievable, as described in Sec. 304(b)(2) of
the Clean Water Act.
BMP - Best management practice. The Clean Water Act authorize EPA to prescribe BMPs as
part of effluent limitation guidelines and standards, or as part of a permit.
BPT - The best practicable control technology currently available, as described in Sec. 304(b)(l)
of the Clean Water Act.
Categorical Pretreatment Standards - Limitations on pollutant discharges to POTWs
promulgated by EPA in accordance with Section 307 of the Clean Water Act that apply to
specified process wastewaters of particular industrial categories.
CESQG - Conditionally Exempt Small Quantity Generators.
CFR- Code of Federal Regulations, published by the U.S. Government Printing Office. A
codification of the general and permanent rules published in the Federal Register by the
Executive departments and agencies of the federal government.
CIU - Categorical Industrial User. An industrial user subject to national categorical pretreatment
standards.
Control Authority - POTW, state, or EPA Region that is responsible for permitting, sampling,
and inspecting industrial users that discharge to the POTW. The Control Authority is (1) the
POTW if the POTWs submission for its pretreatment program (§403.3(t)(l)) has been approved
in accordance with the requirements of §403.11; or (2) the Approval Authority (state or EPA
Region) if the submission has not been approved.
CWA - Clean Water Act. Federal legislation enacted by Congress to "restore and maintain the
chemical, physical, and biological integrity of the Nation's waters" (Federal Water Pollution
Control Act of 1972, as amended, 33 U.S.C. 1251 et seq.).
DCN - Document Control Number.
I'M
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Section 17- Glossary And List of Acronyms
Direct Discharge - The discharge of a pollutant or pollutants directly to a water of the United
States.
Discharge - The conveyance of wastewater to: (1) United States surface waters such as rivers,
lakes, and oceans, or (2) a publicly owned, privately owned, federally owned, combined, or other
treatment works.
DIU - Dental Industrial User. New classification of CIU specifically tailored to the National
Categorical Pretreatment Standards for the Dental Category.
DMR - Discharge Monitoring Report.
Effluent Limitation - Any restriction, including schedules of compliance, established by a state
or the Administrator on quantities, rates, and concentrations of chemical, physical, biological,
and other constituents that are discharged from point sources into navigable waters, the waters of
the contiguous zone, or the ocean. (CWA Sections 301(b) and 304(b).)
ETV - Environmental Technologies Verification.
EPA - U.S. Environmental Protection Agency.
FDA - Food and Drug Administration.
FFDCA - Federal Food, Drug, and Cosmetic Act.
Filtration - A process for removing particulate matter from water by passage through porous
media.
FR- Federal Register, published by the U.S. Government Printing Office, Washington, D.C. A
publication making available to the public regulations and legal notices issued by federal
agencies.
Indirect Discharge - The discharge of a pollutant or pollutants to a POTW.
Ion exchange - Process using a resin formulated to adsorb cationic or anionic species.
ISO - International Organization for Standardization.
IU - Industrial User.
Loadings - Mass of pollutants being discharged in the wastewater from dental offices to POTWs
and from POTWs to surface waters.
Mercury - As it pertains to the dental industry, mercury is a component of amalgam fillings. As
found in wastewater, mercury is a concern to human health because it is a persistent,
bioaccumulative, toxic element; certain microorganisms can change mercury into
methylmercury, a highly toxic form that builds up in fish, shellfish, and animals that eat fish.
Mono-fill - An ultimate disposal technique for wastewater treatment plant sludge in which the
sludge is applied to a landfill designed for sludge only.
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Section 17- Glossary And List of Acronyms
MOU - Memorandum of Understanding.
NACWA - National Association of Clean Water Agencies.
NAICS - North American Industry Classification System. This system is a unique method for
classifying business establishments. Adopted in 1997 to replace the old Standard Industrial
Classification (SIC) system, it is the industry classification system used by the statistical
agencies of the United States.
NPDES - The National Pollutant Discharge Elimination System, authorized under Sec. 402 of
the Clean Water Act. NPDES requires permits for discharge of pollutants from any point source
into waters of the United States.
NSCIU - Non-Significant Categorical Industrial User.
NSPS -New source performance standards, as described in Sec. 306 of the CWA.
OSHA - Occupational Safety and Health Administration.
POTW - Publicly owned treatment works, as defined at 40 CFR 403.3(o). POTWs are generally
any state or municipality-owned sewage treatment plant that recycles, reclaims, or treats liquid
municipal sewage and/or liquid industrial wastes.
PPA - Pollution Prevention Act of 1990 (42 U.S.C. 13101 et seq., Pub.L. 101-508, November 5,
1990).
Pretreatment -The reduction of the amount of pollutants, the elimination of pollutants, or the
alteration of the nature of pollutant properties in wastewater prior to or in lieu of discharging or
otherwise introducing such pollutants into a POTW.
Pretreatment Standard - A regulation that establishes industrial wastewater effluent quality
required for transfer to a POTW (CWA Section 307(b)).
PSES - Pretreatment standards for existing sources, as described in Sec. 307(b) of the CWA.
PSNS - Pretreatment standards for new sources, as described in Sec. 307(b) and (c) of the CWA.
QSC - Quicksilver Caucus of the Environmental Council of States.
RCRA - Resource Conservation and Recovery Act (PL 94-580) of 1976, as amended (42 U.S.C.
6901, et seq.).
SBA - Small Business Administration.
Sedimentation - Separation of solids and liquids from mixtures (solid settling).
SIC - Standard Industrial Classification. A numerical categorization system used by the U.S.
Department of Commerce to catalogue business entities and economic activity. SIC codes refer
to the products, or groups of products, produced or distributed, or to services rendered, by an
operating establishment. SIC codes are used to group establishments by the goods and services
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Section 17- Glossary And List of Acronyms
they provide and the economic activities in which they are engaged. SIC codes often denote a
facility's primary, secondary, tertiary, etc. economic activities.
SIU - Significant Industrial User. An indirect discharger that is the focus of control efforts under
the national pretreatment program. This includes all indirect dischargers subject to national
categorical pretreatment standards, and all other indirect dischargers that contribute 25,000
gallons per day or more of process wastewater, or which make up five percent or more of the
hydraulic or organic loading to the POTW, subject to certain exceptions.
Sludge - The accumulated solids separated from liquids during processing (treatment).
Surface Waters - Waters of the United States including, but not limited to, oceans and all
interstate and intrastate lakes, rivers, streams, creeks, mudflats, sand flats, wetlands, sloughs,
prairie potholes, wet meadows, playa lakes, and natural ponds.
TCLP - Toxicity Characteristic Leaching Procedure. See 40 CFR 261.24.
TRI - Toxics Release Inventory.
TWF - Toxic Weighting Factor. A factor developed for various pollutants using a combination
of toxicity data on human health and aquatic life. EPA uses toxic weighting factors in
determining the amount of toxicity that a pollutant may exert on human health and aquatic life
relative to other pollutants.
TWPE - Toxic Weighted Pound-Equivalent. Pound of pollutant adjusted for relative toxicity;
determined by multiplying the pound of pollutant by the TWF.
Wastewater - For this document, water emanating from dental facility.
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