Vol. 79 Wednesday, 

No. 204 October 22, 2014 

Part III 

Environmental Protection Agency 

40 CFR Parts 403 and 441 

Effluent Limitations Guidelines and Standards for the Dental Category; 

Proposed Rule 


tkelley on DSK3SPTVN1PROD with PROPOSALS3
63258 Federal Register / Vol. 79, No. 204 / Wednesday, October 22, 2014 / Proposed Rules 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Parts 403 and 441 

[EPA–HQ–OW–2014–0693; FRL–9911–63– 

OW] 

RIN 2040–AF26 

Effluent Limitations Guidelines and 

Standards for the Dental Category 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: EPA is proposing technologybased pretreatment standards under the 

Clean Water Act (CWA) for discharges 

of pollutants into publicly owned 

treatment works (POTWs) from existing 

and new dental practices that discharge 

dental amalgam. Dental amalgam 

contains mercury in a highly 

concentrated form that is relatively easy 

to collect and recycle. Dental offices are 

the main source of mercury discharges 

to POTWs. Mercury is a persistent and 

bioaccumulative pollutant in the 

environment with well-documented 

neurotoxic effects on humans. Mercury 

pollution is widespread and comes from 

many diverse sources such as air 

deposition from municipal and 

industrial incinerators and combustion 

of fossil fuels. Mercury easily becomes 

diffuse in the environment and mercury 

pollution is a global problem. Removing 

mercury from the waste stream when it 

is in a concentrated and easy to handle 

form like in waste dental amalgam is an 

important and commonsense step to 

take to prevent that mercury from being 

released back into the environment 

where it can become diffuse and a 

hazard to humans. 

The proposal would require dental 

practices to comply with requirements 

for controlling the discharge of mercury 

and other metals in dental amalgam into 

POTWs based on the best available 

technology or best available 

demonstrated control technology. 

Specifically, the requirements would be 

based on the use of amalgam separators 

and best management practices (BMPs). 

Amalgam separators are a practical, 

affordable and readily available 

technology for capturing mercury and 

other metals before they are discharged 

into sewers and POTWs. EPA is also 

proposing to amend selected parts of the 

General Pretreatment Regulations to 

streamline oversight requirements for 

the dental sector. EPA expects 

compliance with this proposed rule 

would reduce the discharge of metals to 

POTWs by at least 8.8 tons per year, 

about half of which is mercury. EPA 

estimates the annual cost of the 

proposed rule would be $44 to $49 

million. 

DATES: Comments on this proposed rule 

must be received on or before December 

22, 2014. Under the Paperwork 

Reduction Act (PRA), comments on the 

information collection provisions must 

be received by the Office of 

Management and Budget (OMB) on or 

before November 21, 2014. EPA will 

conduct a public hearing on November 

10, 2014 at 1 p.m. in the William J. 

Clinton Building—East Room 1153, 

1201 Constitution Avenue NW., 

Washington, DC. 

ADDRESSES: Submit your comments, 

identified by docket identification (ID) 

number EPA–HQ–OW–2014–0693 by 

one of the following methods: 

• http://www.regulations.gov: Follow 

the on-line instructions for submitting 

comments. 

• Email: OW-Docket@epa.gov, 

Attention Docket ID number EPA–HQ– 

OW–2014–0693. 

• Mail: Water Docket, Environmental 

Protection Agency, Mail code: 4203M, 

1200 Pennsylvania Ave. NW., 

Washington, DC 20460. Attention 

Docket ID number EPA–HQ–OW–2014– 

0693. Please include a total of three 

copies. In addition, please mail a copy 

of your comments on the information 

collection provisions to the Office of 

Information and Regulatory Affairs, 

OMB, Attn: Desk Officer for EPA, 725 

17th St. NW., Washington, DC 20503. 

• Hand Delivery: Water Docket, EPA 

Docket Center, EPA West Building 

Room 3334, 1301 Constitution Ave. 

NW., Washington, DC, Attention Docket 

ID Number EPA–HQ–OW–2014–0693. 

Such deliveries are only accepted 

during the Docket’s normal hours of 

operation, and special arrangements 

should be made for deliveries of boxed 

information by calling 202–566–2426. 

Instructions: Direct your comments to 

docket ID number EPA–HQ–OW–2014– 

0693. EPA’s policy is that all comments 

received will be included in the public 

docket without change and may be 

made available online at http://

www.regulations.gov, including any 

personal information provided, unless 

the comment includes information 

claimed to be Confidential Business 

Information (CBI) or other information 

whose disclosure is restricted by statute. 

Do not submit information that you 

consider to be CBI or otherwise 

protected through www.regulations.gov 

or email. The http://

www.regulations.gov Web site is an 

‘‘anonymous access’’ system, which 

means EPA will not know your identity 

or contact information unless you 

provide it in the body of your comment. 

If you send an email comment directly 

to EPA without going through http://

www.regulations.gov your email address 

will be automatically captured and 

included as part of the comment that is 

placed in the public docket and made 

available on the Internet. If you submit 

an electronic comment, EPA 

recommends that you include your 

name and other contact information in 

the body of your comment and with any 

disk or CD–ROM you submit. If EPA 

cannot read your comment due to 

technical difficulties and cannot contact 

you for clarification, EPA may not be 

able to consider your comment. 

Electronic files should avoid the use of 

special characters, any form of 

encryption, and be free of any defects or 

viruses. 

Docket: All documents in the docket 

are listed in the http://

www.regulations.gov index. A detailed 

record index, organized by subject, is 

available on EPA’s Web site at http://

water.epa.gov/scitech/wastetech/guide/

dental/index.cfm. Although listed in the 

index, some information is not publicly 

available, e.g., CBI or other information 

whose disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, will be publicly 

available only in hard copy. Publicly 

available docket materials are available 

either electronically in http://

www.regulations.gov or in hard copy at 

the Water Docket in the EPA Docket 

Center, EPA/DC, EPA West William 

Jefferson Clinton Bldg., Room 3334, 

1301 Constitution Ave. NW., 

Washington, DC. The Public Reading 

Room is open from 8:30 a.m. to 4:30 

p.m., Monday through Friday, excluding 

legal holidays. The telephone number 

for the Public Reading Room is 202– 

566–1744, and the telephone number for 

the Water Docket is 202–566–2426. 

Pretreatment Hearing Information: 

EPA will conduct a public hearing on 

the proposed pretreatment standards on 

November 10, 2014 at 1:00 p.m. in the 

William Jefferson Clinton Building EPA 

East Building—East Room 1153, 1201 

Constitution Avenue NW., Washington, 

DC. No registration is required for this 

public hearing. During the pretreatment 

hearing, the public will have an 

opportunity to provide oral comment to 

EPA on the proposed pretreatment 

standards. EPA will not address any 

issues raised during the hearing at that 

time but these comments will be 

included in the public record for the 

rule. For security reasons, we request 

that you bring photo identification with 

you to the meeting. Also, if you let us 

know in advance of your plans to 

attend, it will expedite the process of 


tkelley on DSK3SPTVN1PROD with PROPOSALS3
Federal Register / Vol. 79, No. 204 / Wednesday, October 22, 2014 / Proposed Rules 63259 

1See Section XXI for a definition of Control 

Authority. 

signing in. Seating will be provided on 

a first-come, first-served basis. Please 

note that parking is very limited in 

downtown Washington, and use of 

public transit is recommended. The EPA 

Headquarters complex is located near 

the Federal Triangle Metro station. 

Upon exiting the Metro station, walk 

east to 12th Street. On 12th Street, walk 

south to Constitution Avenue. At the 

corner, turn right onto Constitution 

Avenue and proceed to the EPA East 

Building entrance. 

FOR FURTHER INFORMATION CONTACT: 

Damon Highsmith, Engineering and 

Analysis Division (4303T), Office of 

Water, Environmental Protection 

Agency, 1200 Pennsylvania Ave. NW., 

Washington, DC 20460–0001; telephone: 

202–566–2504; email: 

highsmith.damon@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Table of Contents 

I. Regulated Entities 

II. How To Submit Comments 

III. Supporting Documentation 

IV. Overview 

V. Legal Authority 

VI. Purpose and Summary of Proposed Rule 

VII. Solicitation of Data and Comments 

VIII. Background 

IX. Description of the Dental Industry 

X. Summary of Data Collection 

XI. Wastewater Characteristics, Dental Office 

Configurations, and Technology Options 

XII. Scope/Applicability 

XIII. Subcategorization 

XIV. Proposed Regulation 

XV. Technology Costs 

XVI. Economic Impact Analysis 

XVII. Pollutant Reductions to POTWs and 

Surface Waters 

XVIII. Cost Effectiveness 

XIX. Environmental Assessment 

XX. Non-Water Quality Environmental 

Impacts Associated With the Proposed 

Technology Basis 

XXI. Implementation and Proposed Changes 

to General Pretreatment Regulations in 

40 CFR Part 403 

XXII. Statutory and Executive Order Reviews 

I. Regulated Entities 

Entities potentially regulated by this 

action include: 

Category Example of regulated entity 

North American 

Industry 

Classification System (NAICS) code 

Industry .................................................... A general dentistry practice or large dental facility where mercury amalgam is 

placed or removed.

621210 

States ...................................................... Where they are the Control Authority 1 ................................................................... 221320 

Municipalities ........................................... POTWs and other municipally owned facilities that receive pollutants from dental 

offices.

221320 

This section is not intended to be 

exhaustive, but rather provides a guide 

for readers regarding entities likely to be 

regulated by this proposed action. Other 

types of entities that do not meet the 

above criteria could also be regulated. 

To determine whether your facility 

would be regulated by this proposed 

action, you should carefully examine 

the applicability criteria listed in 

§ 441.10 and the definitions in § 441.20 

of this proposed rule and detailed 

further in Section XII of this preamble. 

If you still have questions regarding the 

proposed applicability of this action to 

a particular entity, consult the person 

listed under FOR FURTHER INFORMATION

CONTACT. 

II. How To Submit Comments 

The public may submit comments in 

written or electronic form. (see 

ADDRESSES). Electronic comments must 

be identified by the docket ID number 

EPA–HQ–OW–2014–0693 and must be 

submitted as a WordPerfect, MS Word 

or ASCII text file, avoiding the use of 

special characters and any form of 

encryption. EPA requests that any 

graphics included in electronic 

comments also be provided in hardcopy form. EPA also will accept 

comments and data on disks in the 

aforementioned file formats. Electronic 

comments received on this document 

may be filed online at many Federal 

Depository Libraries. No CBI should be 

sent by email. 

III. Supporting Documentation 

The proposed rule is supported by a 

number of documents including: 

• Technical and Economic 

Development Document for Proposed 

Effluent Limitations Guidelines and 

Standards for the Dental Category 

(TEDD), Document No. EPA–821–R–14– 

006. 

The TEDD summarizes the technical 

and economic analysis described in this 

document. The TEDD and additional 

records are available in the public 

record for this proposed rule and on 

EPA’s Web site at http://water.epa.gov/ 

scitech/wastetech/guide/dental/

index.cfm. They are available in hard 

copy from the National Service Center 

for Environmental Publications 

(NSCEP), U.S. EPA/NSCEP, P.O. Box 

42419, Cincinnati, Ohio 45242–2419, 

telephone 800–490–9198, http://

epa.gov/ncepihom. 

IV. Overview 

The preamble describes the terms, 

acronyms, and abbreviations used in 

this document; the background 

documents that support these proposed 

regulations; the legal authority for the 

proposed rules; a summary of the 

options considered for the proposal; 

background information; and the 

technical and economic methodologies 

used by the Agency to develop these 

proposed regulations. This preamble 

also solicits comment and data on 

specific areas of interest. 

V. Legal Authority 

EPA is proposing this regulation 

under the authorities of sections 101, 

301, 304, 306, 307, 308, and 501 of the 

CWA, 33 U.S.C. 1251, 1311, 1314, 1316, 

1317, 1318, 1342 and 1361 and pursuant 

to the Pollution Prevention Act of 1990, 

42 U.S.C. 13101 et seq. 

VI. Purpose and Summary of Proposed 

Rule 

Across the United States, many states 

and POTWs (also referred to as 

municipal wastewater treatment plants) 

are working toward the goal of reducing 

discharges of mercury to POTWs. 

Mercury is a persistent and 

bioaccumulative pollutant with welldocumented effects on human health. 

On November 6, 2013, the United States 

joined the Minamata Convention on 

Mercury, a new multilateral 

environmental agreement not yet in 

force that addresses specific human 

activities that are contributing to 

widespread mercury pollution. The 

agreement identifies dental amalgam as 

a mercury-added product for which 

certain measures should be taken. 

Specifically, the Convention lists nine 


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2This estimate is based on the average annualized 

cost for dentists that do not currently have an 

amalgam separator. See DCN DA00145. 

measures for phasing down the use of 

mercury in dental amalgam, including 

promoting the use of best environmental 

practices in dental facilities to reduce 

releases of mercury and mercury 

compounds to water and land. Nations 

that are parties to the Convention are 

required to implement at least two of 

the nine measures to address dental 

amalgam. 

Many studies have been conducted in 

an attempt to identify the sources of 

mercury entering POTWs. According to 

the 2002 Mercury Source Control and 

Pollution Prevention Program Final 

Report (DCN DA00006) prepared by the 

National Association of Clean Water 

Agencies (NACWA), dentists are the 

main source of mercury discharges to 

POTWs. A study funded by the 

American Dental Association (ADA) 

published in 2005 estimated that 50% of 

mercury entering POTWs was 

contributed by dental offices (DCN 

DA00163). Mercury is discharged in the 

form of dental amalgam when dentists 

remove old amalgam fillings from 

cavities, and from excess amalgam 

removed when a dentist places a new 

filling. 

EPA estimates that across the United 

States 4.4 tons of mercury from waste 

dental amalgam are collectively 

discharged into POTWs annually. 

Mercury at POTWs frequently partitions 

to the sludge, the solid material that 

remains after wastewater is treated. 

Mercury from amalgam can then make 

its way into the environment through 

the incineration, landfilling, or land 

application of sludge or through surface 

water discharge. Once deposited, certain 

microorganisms can change mercury 

into methylmercury, a highly toxic form 

of mercury that accumulates in fish, 

shellfish, and animals that eat fish. Fish 

and shellfish are the main sources of 

methylmercury exposure to humans. 

Today’s proposed pretreatment 

standards would control mercury 

discharges to POTWs by requiring 

dentists to reduce their discharge of 

dental amalgam to a level achievable 

through the use of the best available 

technology (a combination of amalgam 

separators and the use of BMPs. In order 

to simplify compliance with, and 

enforcement of, the numeric reduction 

requirements, the proposed rule would 

allow dentists to demonstrate 

compliance through the proper use of 

amalgam separators rather than through 

discharge monitoring. Removing 

concentrated sources of mercury waste 

opportunistically, such as through lowcost amalgam separators at dental 

offices (average annual cost per dental 

office: $700 2), is a common sense 

solution to managing mercury where it 

is most concentrated within the waste 

stream that would otherwise be released 

to air, land, and water. 

Additionally, EPA is proposing to 

amend selected parts of the General 

Pretreatment Regulations (40 CFR part 

403) in order to streamline permitting 

and oversight requirements specific to 

the dental sector. The number of dental 

offices that would likely be subject to 

national pretreatment standards is 

approximately ten times the current 

number of Categorical Industrial Users 

(CIUs). The proposed changes to 40 CFR 

part 403 reflect EPA’s recognition that 

the current regulatory framework needs 

to be adjusted for the effective 

implementation and enforcement of 

these pretreatment requirements 

affecting the dental industry. When 

categorical pretreatment requirements 

apply to an industry, it creates certain 

oversight requirements. While other 

industries subject to categorical 

pretreatment requirements typically 

consist of tens to hundreds of facilities, 

the dental industry consists of 

approximately 100,000 facilities, 

making oversight of this large number of 

facilities subject to categorical 

pretreatment standards much more 

challenging. 

VII. Solicitation of Data and Comments 

EPA solicits comments on the 

proposed rule, including EPA’s 

rationale as described in this preamble. 

EPA seeks comments on issues 

specifically identified in this document 

as well as any other issues that are not 

specifically addressed in this document. 

Comments are most helpful when 

accompanied by specific examples and 

supporting data. Specifically, EPA 

solicits information and data on the 

following topics. 

1. Data demonstrating the 

effectiveness of polishing, or the use of 

sorbent columns after solids separation, 

in reducing mercury discharges from 

dental offices. 

2. Data on costs, performance, 

affordability and availability of 

polishing in combination with amalgam 

separators. 

3. Ways for dental offices to 

demonstrate compliance with this 

proposed rule, and how much reporting 

should be required. 

4. Information on EPA’s approach for 

addressing offices where no dental 

amalgam is applied or removed, and its 

approach for offices that already employ 

a separator (including cases where the 

separator was installed as a result of a 

program required by a state or other 

locality and where the separator has a 

certified removal efficiency that is lower 

than 99.0%). 

5. Information on the frequency of 

emergency removals at dental offices 

that do not routinely place or remove 

amalgam. 

6. EPA seeks comment on its 

approach for addressing offices where 

no dental amalgam is placed or removed 

except in limited emergency 

circumstances, and its approach for 

offices that have already installed an 

amalgam separator. 

7. EPA proposes an inspection 

frequency of at least once per month to 

ensure proper operation and 

maintenance of the amalgam separator. 

EPA solicits comment on this frequency 

as well as others, and justifications for 

alternative approaches. 

8. Data on the number of dentists in 

practices potentially subject to this rule 

that do not place or remove dental 

amalgam and on the number of dentists 

in practices excluded from the proposed 

rule such as oral pathology, oral and 

maxillofacial radiology, oral and 

maxillofacial surgery, orthodontics, 

periodontics, and prosthodontics. EPA 

also solicits comment on its estimate of 

the number of dentists in dental 

specialties that are not subject to this 

proposed rule. 

9. Other technologies not discussed in 

this proposed rule that have 

demonstrated an ability to reduce 

discharges of mercury from dental 

offices and their associated costs. 

10. Data regarding EPA’s analysis of 

clinics and very large facilities. 

11. EPA’s proposed revisions to 40 

CFR part 403, including revisions to 

create the DIU category, and the means 

of evaluating ongoing compliance for 

the purposes of maintaining the DIU 

designation. 

12. Information about mobile facilities 

used to treat patients. EPA seeks 

information on the number, size, 

operation and financial characteristics 

of mobile facilities that offer dental 

treatment. 

13. EPA’s estimate of the number of 

large institutional practices, including 

large facilities operated by the Federal 

Government, and the characteristics 

(chair size, number of practitioners, 

currently employed mercury reduction 

approaches, incremental cost of 

proposed requirements) of these 

facilities. 

14. Additional information on 

equipment needs and costs for starting 

a dental practice including information 

on the life of the dental equipment. 


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15. Additional information on low 

revenue dental offices and if they could 

represent baseline closures (see 

discussion in Section XVI). 

16. Additional information on the 

location and characteristics of low 

revenue dental offices ((1) single-dentist 

and/or part-time businesses that provide 

services as a subcontractor on an 

independent fee-for-service basis (2) 

non-profit groups, or (3) non-viable as 

for-profit businesses). 

17. Information on requiring an 

efficiency that exceeds the ISO 

standard. 

18. The proposal would greatly 

reduce potential requirements that 

would otherwise apply to control 

authorities with respect to dental 

dischargers. EPA solicits comments on 

its estimate of burden and costs 

associated with these reduced 

requirements. In particular, EPA solicits 

data from control authorities located in 

municipalities or states where similar 

mandatory dental amalgam reduction 

programs exist. 

VIII. Background 

A. Clean Water Act 

Congress passed the Federal Water 

Pollution Control Act Amendments of 

1972, also known as the Clean Water 

Act, to ‘‘restore and maintain the 

chemical, physical, and biological 

integrity of the Nation’s waters.’’ (33 

U.S.C. 1251(a)). The CWA establishes a 

comprehensive program for protecting 

our nation’s waters. Among its core 

provisions, the CWA prohibits the 

discharge of pollutants from a point 

source to waters of the U.S. except as 

authorized under the CWA. Under 

section 402 of the CWA, EPA authorizes 

discharges by a National Pollutant 

Discharge Elimination System (NPDES) 

permit. The CWA also authorizes EPA 

to establish national technology-based 

effluent limitations guidelines and 

standards (effluent guidelines or ELGs) 

for discharges from different categories 

of point sources, such as industrial, 

commercial, and public sources. 

Congress recognized that regulating 

only those sources that discharge 

effluent directly into the nation’s waters 

would not be sufficient to achieve the 

CWA’s goals. Consequently, the CWA 

requires EPA to promulgate nationallyapplicable pretreatment guidelines and 

standards that restrict pollutant 

discharges from facilities that discharge 

wastewater indirectly through sewers 

flowing to POTWs. (see CWA sections 

304(g), 307(b) and (c), 33 U.S.C. 1314(g), 

and 1317(b) and (c)). National 

pretreatment standards are established 

for those pollutants in wastewater from 

indirect dischargers that may pass 

through, interfere with or are otherwise 

incompatible with POTW operations. 

Generally, pretreatment standards are 

designed to ensure that wastewaters 

from direct and indirect industrial 

dischargers are subject to similar levels 

of treatment. In addition, POTWs are 

required to implement local treatment 

limits applicable to their industrial 

indirect dischargers to satisfy any local 

requirements. (see 40 CFR 403.5). 

Direct dischargers must comply with 

effluent limitations in NPDES permits. 

Indirect dischargers, who discharge 

through POTWs, must comply with 

pretreatment standards. Technologybased effluent limitations in NPDES 

permits are derived from effluent 

limitations guidelines (CWA sections 

301 and 304) and new source 

performance standards (CWA section 

306) promulgated by EPA, or based on 

best professional judgment where EPA 

has not promulgated an applicable 

effluent guideline or new source 

performance standard. Additional 

limitations based on water quality 

standards (CWA sections 301(b)(1)(C) 

and 303) may also be included in the 

permit in certain circumstances. The 

ELGs are established by regulation for 

categories of industrial dischargers and 

are based on the degree of control that 

can be achieved using various levels of 

pollution control technology. 

EPA promulgates national effluent 

limitations guidelines and standards of 

performance for major industrial 

categories for three classes of pollutants: 

(1) Conventional pollutants (total 

suspended solids, oil and grease, 

biochemical oxygen demand, fecal 

coliform, and pH); (2) toxic pollutants 

(e.g., toxic metals such as chromium, 

lead, mercury, nickel, and zinc; toxic 

organic pollutants such as benzene, 

benzo-a-pyrene, phenol, and 

naphthalene) as specified in CWA 

section 307 and; (3) non-conventional 

pollutants, those pollutants that are 

neither conventional nor toxic (e.g., 

ammonia-N, formaldehyde, and 

phosphorus). 

B. Effluent Guidelines and Standards 

Program 

Effluent limitations guidelines and 

standards are technology-based 

regulations that are developed by EPA 

for a category of dischargers. These 

regulations are based on the 

performance of control and treatment 

technologies. The legislative history of 

CWA section 304(b), describes the need 

to achieve progressively higher levels of 

control through research and 

development of new processes, 

modifications, replacement of obsolete 

plans and processes, and other 

improvements in technology, taking into 

account the cost of controls. Congress 

also directed that EPA not consider 

water quality impacts on individual 

water bodies as the guidelines are 

developed. See Statement of Senator 

Muskie (Oct. 4, 1972), reprinted in 

Legislative History of the Water 

Pollution Control Act Amendments of 

1972, at 170. (U.S. Senate, Committee 

on Public Works, Serial No. 93–1, 

January 1973.) 

There are standards applicable to 

direct dischargers (dischargers to 

surface waters), and standards 

applicable to indirect dischargers 

(discharges to publicly owned treatment 

works or POTWs). The standards 

relevant to this rulemaking are 

summarized here. 

1. Best Available Technology 

Economically Achievable (BAT) 

BAT effluent limitations guidelines 

apply to direct dischargers of toxic and 

nonconventional pollutants. In general, 

BAT effluent limitations guidelines 

represent the best economically 

achievable performance of facilities in 

the industrial subcategory or category. 

The factors considered in assessing BAT 

include the cost of achieving BAT 

effluent reductions, the age of 

equipment and facilities involved, the 

process employed, potential process 

changes, and non-water quality 

environmental impacts including energy 

requirements, and such other factors as 

the Administrator deems appropriate. 

The Agency has considerable discretion 

in assigning the weight to be accorded 

these factors. An additional statutory 

factor considered in setting BAT is 

economic achievability. Generally, EPA 

determines economic achievability on 

the basis of total costs to the industry 

and the effect of compliance with BAT 

limitations on overall industry and 

subcategory financial conditions. Where 

existing performance is uniformly 

inadequate, BAT may reflect a higher 

level of performance than is currently 

being achieved based on technology 

transferred from a different subcategory 

or category. BAT may be based upon 

process changes or internal controls, 

even when these technologies are not 

common industry practice. 

2. New Source Performance Standards 

(NSPS) 

NSPS reflect effluent reductions that 

are achievable based on the best 

available demonstrated control 

technology. Owners of new facilities 

have the opportunity to install the best 

and most efficient production processes 

and wastewater treatment technologies. 


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3New Mexico has a similar program that is 

scheduled to go into effect in 2015. 

4Puerto Rico, the Virgin Islands, Pacific Islands 

and Tribal Nations are not included in this analysis. 

As a result, NSPS should represent the 

most stringent controls attainable 

through the application of the best 

available demonstrated control 

technology for all pollutants (that is, 

conventional, nonconventional, and 

priority pollutants). In establishing 

NSPS, EPA is directed to take into 

consideration the cost of achieving the 

effluent reduction and any non-water 

quality environmental impacts and 

energy requirements. 

3. Pretreatment Standards for Existing 

Sources (PSES) 

Pretreatment standards apply to 

discharges of pollutants to POTWs 

rather than discharges to waters of the 

United States. Pretreatment Standards 

for Existing Sources are designed to 

prevent the discharge of pollutants that 

pass through, interfere with, or are 

otherwise incompatible with the 

operation of POTWs, including sludge 

disposal methods of POTWs. Categorical 

pretreatment standards for existing 

sources are technology-based and are 

analogous to BAT effluent limitations 

guidelines. 

The General Pretreatment 

Regulations, which set forth the 

framework for the implementation of 

categorical pretreatment standards, are 

found at 40 CFR part 403. 

4. Pretreatment Standards for New 

Sources (PSNS) 

Like PSES, PSNS are designed to 

prevent the discharges of pollutants that 

pass through, interfere with, or are 

otherwise incompatible with the 

operation of POTWs. New indirect 

discharges have the opportunity to 

incorporate into their facilities the best 

available demonstrated technologies. 

The Agency typically considers the 

same factors in promulgating PSNS as it 

considers in promulgating NSPS. 

5. BMPs 

Section 304(e) of the CWA authorizes 

the Administrator to publish 

regulations, in addition to effluent 

limitations guidelines and standards for 

certain toxic or hazardous pollutants, 

‘‘to control plant site runoff, spillage or 

leaks, sludge or waste disposal, and 

drainage from raw material storage 

which the Administrator determines are 

associated with or ancillary to the 

industrial manufacturing or treatment 

process . . . and may contribute 

significant amounts of such pollutants 

to navigable waters.’’ In addition, 

section 304(g), read in concert with 

section 501(a), authorizes EPA to 

prescribe as wide a range of 

pretreatment requirements as the 

Administrator deems appropriate in 

order to control and prevent the 

discharge into navigable waters either 

directly or through POTWs any 

pollutant which interferes with, passes 

through, or otherwise is incompatible 

with such treatment works. (see also 

Citizens Coal Council v. U.S. EPA, 447 

F3d 879, 895–96 (6th Cir. 2006) 

(upholding EPA’s use of non-numeric 

effluent limitations and standards); 

Waterkeeper Alliance, Inc. v. U.S. EPA, 

399 F.3d 486, 496–97, 502 (2d Cir. 2005) 

(EPA use of non-numerical effluent 

limitations in the form of BMPs are 

effluent limitations under the CWA); 

and Natural Res. Def. Council, Inc. v. 

EPA, 673 F.2d 400, 403 (D.C. Cir. 1982) 

(‘‘section 502(11) [of the CWA] defines 

‘effluent limitation’ as ‘any restriction’ 

on the amounts of pollutants 

discharged, not just a numerical 

restriction.’’) 

C. The National Pretreatment Program, 

40 CFR Part 403 

The General Pretreatment Regulations 

of 40 CFR part 403 establish 

responsibilities among federal, state, 

local government, industry, and the 

public to implement pretreatment 

standards to control pollutants that pass 

through or interfere with the POTW 

treatment processes or that can 

contaminate sewage sludge. The 

regulations, which have been revised 

numerous times since originally 

published in 1978, consist of 20 sections 

and seven appendices. The General 

Pretreatment Regulations use two terms 

describing oversight responsibilities 

under those regulations. One is the term 

Control Authority. The ‘‘Control 

Authority’’ refers to the POTW if the 

POTW has an approved Pretreatment 

Program, or the Approval Authority if 

the program has not been approved. The 

term Approval Authority describes the 

party with responsibility to administer 

the National Pretreatment Program, 

which is either a state with an approved 

state Pretreatment Program or, in a state 

without an approved Pretreatment 

Program, the EPA region for that state 

(40 CFR 403.3(f)). An approved 

Pretreatment Program is comprised of 

legal authorities, procedures, funding, 

local limits, enforcement response plan, 

and the list of significant industrial 

users (SIUs), together which the Control 

Authority uses to implement the 

General Pretreatment Regulations. The 

General Pretreatment Regulations apply 

to all nondomestic sources that 

introduce pollutants into a POTW. 

These sources of indirect discharges are 

more commonly referred to as Industrial 

Users (IUs). All IUs are subject to 

general pretreatment standards (40 CFR 

part 403), including a prohibition on 

discharges causing ‘‘pass through’’ or 

‘‘interference’’ (i.e., cause the POTW to 

violate its permits limits, or interfere 

with the operation of the POTW or the 

beneficial use of its sewage sludge). All 

POTWs with approved Pretreatment 

Programs must develop local limits to 

implement the general pretreatment 

standards. All other POTWs must 

develop such local limits where they 

have experienced ‘‘pass through’’ or 

‘‘interference’’ and such a violation is 

likely to recur. There are approximately 

1,500 POTWs with approved 

Pretreatment Programs and 13,500 small 

POTWs that are not required to develop 

and implement Pretreatment Programs. 

D. State and Local Requirements 

Currently, 12 states (Connecticut, 

Louisiana, Maine, Massachusetts, 

Michigan, New Hampshire, New Jersey, 

New York, Oregon, Rhode Island, 

Vermont, and Washington) have 

implemented mandatory programs to 

reduce dental mercury discharges.3

Additionally, at least 19 localities 

similarly have mandatory dental 

reduction pretreatment programs. These 

mandatory programs require the use of 

amalgam separators and BMPs. Removal 

efficiency requirements for separators in 

mandatory program jurisdictions vary 

from 95% to 99%. A full list of 

jurisdictions with mandatory separator 

requirements can be found in the TEDD 

for this proposed rulemaking. 

Later in this document, EPA estimates 

costs and economic impacts for this 

proposed rule. In order to do so, EPA 

needed to estimate baseline compliance, 

or those dental offices that already have 

amalgam separators installed, and, 

therefore, would incur lower costs and 

impacts from the proposed rule. In order 

to estimate baseline compliance, EPA 

distributed the number of dental offices 

shown in Table IX–1 of Section IX by 

state,4 based on the 2007 Economic 

Census. Because EPA has no data to 

indicate otherwise, EPA assumes 100% 

compliance in the 12 states that require 

amalgam separators. For states without 

mandatory programs, EPA assumed that 

20% of dentists have voluntarily 

installed amalgam separators. As a 

result, EPA estimates approximately 

40% of dental offices, nationally, have 

amalgam separators installed (DCN 

DA00146). EPA, however, welcomes 

data and comment on this assumption. 


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5A firm is a business organization, such as a sole 

proprietorship, partnership, or corporation. 

6EPA recognizes that some dental facilities may 

discharge to a septic system. This proposed rule 

does not apply to such discharges. 

E. 2008 Memorandum of Understanding 

on Reducing Mercury Discharges 

In December 2008, EPA signed a 

Memorandum of Understanding (MOU) 

with the ADA and the NACWA to 

establish and monitor the effectiveness 

of a Voluntary Dental Amalgam 

Discharge Reduction Program. The 

purpose of the MOU is to encourage 

dental offices to voluntarily install and 

properly maintain amalgam separators, 

and recycle the collected amalgam 

waste. Although EPA has not conducted 

a formal evaluation of the effectiveness 

of the MOU, EPA is proposing National 

Pretreatment Standards to accomplish 

the goals of the MOU in a more 

predictable timeframe than a voluntary 

approach. 

F. ADA BMPs and Support for a 

National Rulemaking 

ADA encourages dentists to handle 

mercury and mercury amalgam in a 

manner that is consistent with ADA’s 

‘‘Best Management Practices for 

Amalgam Waste.’’ ADA’s BMPs are 

designed to reduce the amount of 

mercury entering the environment. 

Practices encouraged by these BMPs 

include reducing the volume of bulk 

elemental mercury in dentists’ offices, 

encouraging dentists to recycle amalgam 

to the greatest extent possible, 

preventing mercury from being disposed 

of in medical waste bags, and 

preventing amalgam from entering the 

wastewater stream. In 2007, ADA added 

the use of amalgam separators to their 

BMPs. See DCN DA00165. 

In late 2010, ADA’s Board of Directors 

adopted nine principles upon which 

ADA supported National Pretreatment 

Standards for dental facilities. See DCN 

DA00137. 

IX. Description of the Dental Industry 

The industry category that would be 

affected by this proposed rule is Offices 

of Dentists (NAICS 621210), which 

comprises establishments of health 

practitioners primarily engaged in the 

independent practice of general or 

specialized dentistry, or dental surgery. 

These practitioners operate individual 

or group practices in their own offices 

or in the offices of others, such as 

hospitals or health maintenance 

organization medical centers. They can 

provide either comprehensive 

preventive, cosmetic, or emergency care, 

or specialize in a single field of 

dentistry. 

According to the 2007 Economic 

Census, there were 127,057 U.S. dental 

offices owned or operated by 121,048 

dental firms.5 Only 2% of all dental 

firms were multi-unit with the vast 

majority being single-unit. The growth 

of the number of dental offices has 

remained steady over the past decade 

with an average increase of 1% per year. 

The industry includes mostly small 

businesses with an estimated 99.8% of 

all offices falling below the Small 

Business Administration (SBA) size 

standard ($7 million in annual revenue). 

Average revenues for offices were 

estimated at $739,280 per year with an 

average of 6.50 employees per 

establishment. 

According to ADA data, 

approximately 80% of the dental 

industry engages in general dentistry. 

Approximately 20% are specialty 

dentists such as periodontics, 

orthodontics, radiology, maxillofacial 

surgery, endodontists, or prosthodontics 

(DCN DA00123). 

One way to categorize dental offices is 

based on the number of chairs in each 

facility. The 2007 Economic Census 

does not provide information on the 

distribution of dental offices by the 

number of chairs in each office. 

However, two studies, the ADA 

National Study and a Colorado Study, 

demonstrate distribution of dentist 

offices by number of chairs (DCN 

DA00141 and DCN DA00149). EPA used 

these two sources of data to correlate the 

number of chairs per office to the 

revenue range of dental offices. EPA 

averaged the correlation of these two 

studies. The results are reported in table 

IX–1: 

TABLE IX–1—NUMBER OF DENTAL OFFICES BY NUMBER OF CHAIRS

Number of chairs 

Number of offices by chair size 

ADA survey Colorado 

survey Average 

1–2 chairs .................................................................................................................................... 13,694 10,700 12,197 

3 chairs ........................................................................................................................................ 47,698 27,821 25,835 

4 chairs ........................................................................................................................................ 32,102 27,976 

5 chairs ........................................................................................................................................ 29,388 15,694 15,194 

6 chairs ........................................................................................................................................ 9,399 12,047 

7+ chairs ...................................................................................................................................... 19,079 14,143 16,611 

Total ...................................................................................................................................... 109,859 109,859 109,859 

Dentistry may also be performed at 

larger institutional dental service 

facilities (e.g., clinics or dental schools). 

These facilities are not included in the 

2007 Economic Census data. EPA 

estimates 130 dental institutional 

facilities exist nationwide. EPA 

recognizes that large facilities also may 

exist at installations operated by the 

Federal Government, specifically the 

Department of Defense. While EPA 

intends such facilities would be subject 

to today’s proposed rule, EPA does not 

have information to estimate the 

number of such facilities. 

EPA currently lacks a central database 

on reported discharges from dental 

offices/clinics. Often, EPA looks to 

information in the Toxic Release 

Inventory (TRI) and Discharge 

Monitoring Report (DMR) databases to 

gather information on industrial 

discharges. However, no dental offices/ 

clinics (NAICS Code 621210) are 

required to report releases to TRI. EPA 

identified only five dental offices that 

have National Pollutant Discharge 

Elimination System (NPDES) permit 

information. All dental offices were 

classified as minor dischargers. EPA has 

not found any DMR data indicating that 

any significant number of dental offices 

discharge directly to waters of the U.S. 

Therefore, EPA is not proposing effluent 

limits for direct dischargers.6


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X. Summary of Data Collection 

In developing this proposed rule, EPA 

primarily used data previously collected 

for its Health Services Detailed Study 

including information submitted in 

public comments on the study. EPA also 

collected information and data through 

outreach to a number of stakeholders. 

The following describes EPA’s outreach 

and additional data sources for this 

proposed rule. 

A. Health Services Industry Detailed 

Study on Dental Amalgam 

In 2008, EPA published its Health 

Services Industry Detailed Study on 

Dental Amalgam. In the study, EPA 

compiled information on mercury 

discharges from dental offices, BMPs, 

and amalgam separators. For amalgam 

separators, EPA examined the frequency 

with which they were used; their 

effectiveness in reducing discharges to 

POTWs; and the capital and annual 

costs associated with their installation 

and operation. EPA also conducted a 

POTW pass-through analysis on 

mercury for the industry. This proposed 

rule relies heavily on data collected for 

the study (including information 

submitted in public comments on the 

study). 

B. Environmental Council of the States 

(ECOS) 

EPA participated in several meetings 

with the Quicksilver Caucus (QSC) of 

ECOS. From QSC, EPA collected 

information on implementing 

mandatory amalgam separator programs 

at the state level, mandatory program 

language, and information on 

compliance reporting and monitoring. 

QSC also provided EPA with 

information on efficiency standards for 

amalgam separators. See DCN DA00158. 

C. Environmental Organizations 

EPA met with a coalition of 

environmental organizations, led by the 

Environmental Law and Policy Center 

and the Natural Resources Defense 

Council. Meetings between EPA and the 

coalition of environmental organizations 

focused on identifying impacts of 

discharges of dental amalgam to the 

environment. In Spring 2011, the 

coalition submitted a letter listing its 

suggested BMPs for this proposed rule. 

See DCN DA00136. 

D. ADA 

EPA met with the ADA in 2010 and 

2011. ADA submitted data to EPA on its 

principles for addressing mercury 

discharges from dentists, the 

proportions of specialties in the 

industry, the geographic distribution of 

dentists, financial characteristics of the 

industry, and operating characteristics 

of the industry. See DCN DA00137. 

E. NACWA 

EPA met with NACWA in 2010 and 

2011 to discuss the impact of 

pretreatment standards on POTWs. 

NACWA provided EPA information on 

its members’ experiences with handling 

mercury pollution from dental facilities, 

implementing pretreatment programs 

for dental facilities, and its experiences 

implementing pretreatment standards 

for industries with similar 

characteristics to the dental sector. 

NACWA also provided EPA with 

information on the burden to permitting 

authorities that would be associated 

with implementing a dental amalgam 

pretreatment standard under the 

existing requirements in 40 CFR part 

403. See DCN DA00144. 

F. Amalgam Separator Manufacturers 

EPA met with, or participated in calls 

with, representatives of multiple 

amalgam separator manufacturers. The 

purpose of the meetings was to 

understand how amalgam separators 

work, limitations of the technology, 

manufacturers’ distribution methods, 

installation requirements, capital and 

operation and maintenance costs, 

operation and maintenance 

requirements, effectiveness, equipment 

lifetime, amalgam disposal or recycling 

practices, manufacturing capacity, and 

installation trends. 

G. Air Force Study 

In anticipation of this proposed rule, 

the United States Air Force’s Dental 

Evaluation and Consultation Service 

compiled a synopsis of commonly used 

amalgam separator systems. The 

synopsis describes whether or not the 

separator is International Organization 

for Standardization (ISO) 11143 

certified, the installation requirements, 

the design capacity, maintenance 

requirements for each model, the 

availability of recycling services by the 

manufacturer, size, price, and warranty 

details. EPA incorporated these data 

into the technology cost analysis. The 

synopsis can be found in the TEDD for 

this proposed rule. 

XI. Wastewater Characteristics, Dental 

Office Configurations, and Technology 

Options 

A. Wastewater Sources and Wastewater 

Characteristics 

Dental amalgam consists of 

approximately 49% mercury by weight. 

Mercury is the only metal that is in its 

liquid phase at room temperature, and 

it bonds well with powdered alloy. This 

contributes to its durability in dental 

amalgam. The other half of dental 

amalgam is usually composed of 35% 

silver, 9% tin, 6% copper, 1% zinc and 

small amounts of indium and palladium 

(DCN DA00131). Sources of mercury 

discharges generally occur in the course 

of two categories of activities. The first 

category of discharges may occur in the 

course of treating a patient, such as 

during the placement or removal of a 

filling. When filling a cavity, dentists 

overfill the tooth cavity so that the 

filling can be carved to the proper 

shape. The excess amalgam is typically 

rinsed into a chair-side drain, or 

suctioned out of the patient’s mouth. In 

addition to filling new cavities, dentists 

also remove old cavity restorations that 

are worn or damaged. Removed 

restorations also may be rinsed into the 

chair-side drain or suctioned out of the 

patient’s mouth. The second category of 

mercury discharges occur in the course 

of activities not directly involved with 

the placement or removal of dental 

amalgam. Preparation of dental 

amalgam, disposing of excess amalgam, 

and flushing vacuum lines with 

corrosive chemicals present 

opportunities for mercury from dental 

amalgam to be discharged. 

B. Dental Office Configurations 

The typical plumbing configuration in 

a dental office consists of a chair-side 

trap for each chair, and a central 

vacuum pump with a vacuum pump 

filter. Chair-side traps and vacuum 

pump filters remove approximately 78% 

of dental amalgam particles from the 

wastewater stream (DCN DA00163). 

Offices with multiple chairs typically 

share the vacuum lines between chairs. 

Accordingly, this limits the locations for 

installation of control and treatment 

technologies. Controls may be installed: 

At or near each individual chair; within 

the vacuum system piping; at a central 

location upstream of the vacuum pump; 

or at the exit of the air/water separator 

portion of the vacuum system. Physical 

office and building configurations may 

pose additional considerations, such as 

space limitations, electrical power 

accessibility, and existing sewer 

connections. In the case of very large 

offices, clinics, and medical buildings, it 

may be possible to combine waste flows 

between offices to share or reduce costs. 

C. Control and Treatment Technologies 

and Best Management Practices 

As described previously, one source 

of the discharge of mercury from dental 

amalgam occurs when dental amalgam 

enters the chair-side drain, or is 

suctioned from the patient’s mouth. The 

wastewater then travels through the 

dental facility’s vacuum system. EPA 


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7There may be separators on the market that do 

not notify users when they are in bypass mode or 

otherwise require servicing. These separators would 

not meet ISO certification standards. 

8This does not mean all types of separators are 

compatible at a given dental office. For example, an 

amalgam separator that relies on filtration 

technology may not be compatible with a dry 

vacuum system in place. 

identified two major technologies that 

intercept dental amalgam at this point, 

before it is discharged from the dental 

office and flows to the POTW: 

Separators and ion exchange. EPA also 

identified several BMPs which, when 

employed along with the use of the 

technologies discussed below, further 

reduce the discharge of dental amalgam 

from activities not directly related to the 

placement or removal of dental 

amalgam. 

1. Amalgam Separators 

An amalgam separator is a device 

designed to remove solids from dental 

office wastewater. The amalgam 

separator is placed at some point in the 

vacuum line, before the vacuum line 

intersects with plumbing in other parts 

of the building, and separates solids 

from wastewater. Most separator designs 

rely on the force of the dental facility’s 

vacuum to draw wastewater into the 

separator. However, the separation of 

solids from the wastewater and the exit 

of the wastewater from the separator 

will vary by design of the separator. 

Practically all amalgam separators on 

the market today use sedimentation 

processes. The high specific gravity of 

amalgam allows effective separation of 

amalgam from suspension in 

wastewater. Baffles or tanks can reduce 

the speed of the wastewater flow, 

allowing more amalgam particles to 

settle out. After the solids settle, the 

wastewater is either pumped out, 

decanted during servicing, or is pulled 

through the separator. Sedimentationbased separators are often used over 

other separation technologies for their 

operational simplicity. 

Some amalgam separators may 

combine filtration with separation. 

Different types of filtration units can be 

employed to remove additional 

amalgam particles. The amalgam 

separator may also be designed to 

operate horizontally where wastewater 

is drawn into one side of the separator, 

filtered, and then exits the opposite side 

of the separator. This type of separator 

is designed to be completely replaced 

once it reaches its design solids holding 

capacity. In addition to combined 

separation and filtration units, EPA is 

aware of at least one type of separator 

that utilizes centrifugation. A 

centrifuge-based separator spins the 

water so that the heavier amalgam 

particles are forced to the sides of the 

separator. 

A few amalgam separators combine 

sedimentation (with or without 

filtration) with ion exchange in the same 

unit. This type of separator additionally 

includes a chelating agent or proprietary 

resin. This type of separator often 

requires special cleaning or additives to 

maintain efficiency. 

The typical amalgam separator will 

operate in one of two ways. A twochambered separator is a design 

consisting of a base permanently 

plumbed into the vacuum line, and a 

replaceable filtration cartridge. The 

removable cartridge usually attaches to 

the bottom of the permanent base. As 

wastewater enters the separator from the 

top of the unit, gravity separates the 

wastewater from the air pulling it 

through the vacuum. Air from the 

vacuum continues through the system 

by exiting a bypass at or near the top of 

the base chamber. Wastewater then falls 

through the base of the separator and 

enters the filtration cartridge. As 

additional wastewater enters the 

separator, the filtration cartridge will fill 

to capacity, and wastewater will begin 

to collect at the bottom of the base 

chamber. Gravity forces wastewater in 

the separator through a filtration device 

and out of the separator through a 

decanting tube on the side of the 

separator. The wastewater, less the 

solids retained by the separator, then 

continues through the vacuum system 

and is eventually discharged from the 

dental office and to the sanitary sewer 

and the POTW. The second common 

separator design consists of a single 

chamber that requires wastewater to 

travel through a filtration medium 

before it is drawn out of the separator. 

These separators may be oriented 

vertically so that wastewater enters the 

top of the unit, remains in the separator 

for some time, and allows solids to 

settle. For either design, when the 

filtration cartridge or the separator itself 

reaches the designed solids retention 

capacity, it must be replaced. 

Manufacturers can include replacement 

schedules and capacity levels for 

amalgam separators. 

The vast majority of amalgam 

separators on the market today have 

been evaluated for their ability to meet 

the International Organization for 

Standardization Standard for Dental 

Amalgam Separators (http://

www.iso.org/iso/iso_catalogue/

catalogue_tc/catalogue_detail.htm?

csnumber=42288). This voluntary 

standard setting organization 

established a standard for measuring 

amalgam separator efficiency by 

evaluating the retention of amalgam 

mercury using specified test procedures 

in a laboratory setting. It also includes 

requirements for instructions for use 

and operation and maintenance. In 

order to obtain the ISO certification, a 

separator must achieve 95% removal or 

greater of total mercury. Based on EPA’s 

evaluation of a range of amalgam 

separators as described above that meet 

the ISO standard and that are currently 

on the market, certified separators 

obtain a median of 99.0% total mercury 

removal efficiency (see Section 7 of the 

TEDD). When existing chair side traps 

and vacuum pump filters are used 

upstream of the amalgam separators, the 

combined treatment system can achieve 

total mercury removal rates exceeding 

99% (DCN DA00008). 

EPA is proposing to include certain 

operation, maintenance, and inspection 

activities that have the greatest impact 

on the ability of an amalgam separator 

to achieve its performance as certified. 

Once the separator reaches solids 

retention capacity, vacuum suction will 

begin to diminish or, more commonly, 

the separator will enter bypass mode. 

Wastewater running through a separator 

in bypass mode flows through the 

separator without being filtered, 

rendering the separator ineffective. 

Because many separators can enter 

bypass mode without any noticeable 

effect on vacuum suction, it would be 

important that the unit be checked 

periodically, and if necessary, serviced.7

Solids collected by the amalgam 

separator may be a combination of 

dental amalgam, biological material 

from patients, and any other solid 

material sent down the vacuum line. 

Amalgam separator manufacturer 

instructions should be followed for 

servicing amalgam separators and for 

handling separator waste. Some 

amalgam separator manufacturers also 

offer waste management services. 

Examples of services provided include 

ensuring that waste collected by the 

separator is handled according to state 

and local requirements, and providing 

necessary compliance documentation 

for the facility’s recordkeeping 

requirements. In the event that these 

services are not employed, the facility 

should dispose of amalgam waste in 

accordance with state and local 

requirements. 

Most amalgam separators are 

compatible with both wet and dry 

vacuum systems, and with both large 

and small dental offices.8 As explained 

in Section VIII, currently at least 12 

states and 19 localities have 

implemented mandatory programs to 

reduce dental mercury discharges. All of 

these programs require the use of 


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9 In some cases, the ISO testing results include 

ranges of dissolved mercury in the effluent. 

amalgam separators. Further, many 

dental offices in states or localities 

without mandatory programs have 

voluntarily installed dental amalgam 

separators, and the ADA recommends 

their use as part of its ‘‘Best 

Management Practices for Amalgam 

Waste’’ (2007). As described in Section 

VIII, EPA estimates that 40% of dental 

offices currently employ amalgam 

separators. 

2. Polishing To Remove Dissolved 

Mercury From Wastewater 

Mercury in dental amalgam is present 

in both the suspended and dissolved 

form. The vast majority (>99.6%) is 

suspended (DCN DA00018). An 

additional process sometimes referred to 

as ‘‘polishing’’ uses ion exchange to 

remove dissolved mercury. In contrast 

to amalgam separators that contain an 

ion exchange component in the same 

unit, as discussed in the previous 

section, ‘‘polishing’’ ion exchange refers 

to a separate wastewater treatment 

system added after the amalgam 

separator for the purpose of removing 

dissolved mercury. 

Dissolved mercury has a tendency to 

bind with other chemicals, resulting in 

a charged complex. Ion exchange is the 

process that separates these charged 

amalgam particles from the wastewater. 

Ion exchange does not rely on physical 

settling of particles, and can remove 

very small amalgam and ionic mercury 

particles. This technology may be 

preferable over sedimentation (with or 

without filtration) alone because 

dissolved mercury is removed by this 

process. For example, ion exchange 

might be useful in municipalities that 

have concentration limits on mercury 

(McManus, 2003). EPA is not aware of 

any state regulations that require ion 

exchange. 

For ion exchange to be most effective, 

the incoming wastewater to be treated 

must first have the solids removed. 

Then the wastewater needs to be 

oxidized in order for the resin or 

mercury capturing material to capture 

the dissolved mercury. Therefore, ion 

exchange will not be effective without 

first being preceded by a solids 

collector. As a result, EPA concludes 

this sequential polishing approach, in 

which amalgam separators and ion 

exchange are separate units, is more 

effective than the single units described 

above that combine sedimentation and 

ion exchange. Dental offices needing to 

employ polishing would likely need to 

add a separate ion exchange unit 

following the amalgam separator to 

remove additional mercury from the 

waste stream. 

As explained above, ISO certification 

testing is based on an evaluation of the 

removal of total mercury in a laboratory 

setting and does not differentiate 

removal for the suspended and 

dissolved forms.9 In order to better 

understand the reductions in dissolved 

mercury that can be achieved with the 

addition of ion exchange as polishing, 

EPA reviewed available data on the 

performance from actual installations of 

ion exchange units in addition to 

amalgam separators in dental offices. 

EPA found the use of polishing is 

limited to just a handful of dental 

offices. EPA identified only one study of 

polishing systems, and has not 

identified any further data pertaining to 

the performance of polishing. This one 

study evaluated the additional efficacy 

associated with polishing at two dental 

facilities in response to sanitation 

district concerns over mercury 

discharges. In both cases, the polishing 

systems were installed after the 

amalgam separators but prior to 

discharge into the treatment plant’s 

collection system. While a reduction 

was observed in the final effluent 

mercury after the polishing system was 

installed, preliminary EPA Region 8 

audits showed the total additional 

mercury reductions were typically on 

the order of 0.5% (DCN DA00164). This 

is not surprising since, as indicated 

above, dissolved mercury contributes 

such a small portion to the total amount 

of mercury in dental amalgam. It is 

unclear whether any solid mercury was 

converted to dissolved mercury, and 

additional monitoring data are not yet 

available. 

The capital costs of the polishing 

system, as a stand-alone system, are 

approximately four times that of the 

amalgam separator; the costs for 

chemical use, regenerating the resin, 

filter replacement, and other operational 

costs were not reported. Further, EPA is 

uncertain whether typical dental 

buildings have adequate space to install 

the holding tanks needed to oxidize the 

waste before treatment, as well as space 

for the polishing equipment itself. 

D. Best Management Practices 

EPA considered what BMPs reflect 

the best available technology 

economically achievable or best 

available demonstrated control 

technology—the standards applicable to 

existing and new sources subject to 

categorical pretreatment standards. 

After this review, EPA proposes to 

include certain operation, maintenance, 

and inspection practices as part of the 

technology basis for this proposed rule. 

These practices have the greatest impact 

on the ability of an amalgam separator 

to achieve its performance as certified. 

EPA also proposes to require two 

BMPs to control mercury discharges that 

would not be captured by an amalgam 

separator. Bleach and other corrosive 

cleaners can solubilize bound mercury. 

If corrosive cleaners are used to clean 

vacuum lines that lead to an amalgam 

separator, the line cleaners may 

solubilize any mercury that the 

separator has captured, leading to 

increased mercury discharges. 

Therefore, EPA proposes to require line 

cleaners that do not contain bleach, and 

are of neutral pH. 

Flushing scrap amalgam (contact and 

non-contact), including dental amalgam 

from chair-side traps, screens, vacuum 

pump filters, dental tools, or collection 

devices into drains that do not have a 

solids collecting device presents 

additional opportunities for mercury to 

be discharged from the dental office. 

Therefore, EPA proposes to include a 

BMP that prohibits flushing scrap dental 

amalgam into any drain that is not 

connected to an amalgam separator. 

XII. Scope/Applicability 

As mentioned in the previous section, 

EPA has not identified dental offices/

clinics discharging directly to waters of 

the U.S. Because EPA has very limited 

information on any direct discharge of 

dental amalgam, EPA is not proposing 

effluent limitations guidelines and new 

source performance standards for direct 

dischargers at this time. 

As such, EPA is proposing to apply 

this rule to wastewater discharges to 

POTWs from offices where the practice 

of dentistry is performed, including 

institutions, permanent or temporary 

offices, clinics, mobile units, home 

offices, and facilities, and including 

dental facilities owned and operated by 

Federal, state, or local governments. 

EPA is not proposing to include 

wastewater discharges from dental 

facilities where the practice of dentistry 

consists exclusively of one or more of 

the following dental specialties: oral 

pathology, oral and maxillofacial 

radiology, oral and maxillofacial 

surgery, orthodontics, periodontics, or 

prosthodontics. As described in the 

TEDD, these specialty practices do not 

engage in the practice of restorations or 

removals, and are not expected to have 

any discharges of dental amalgam. 

XIII. Subcategorization 

In developing effluent limitations 

guidelines and pretreatment standards, 

EPA may divide an industry category 

into groupings called ’’subcategories’’ to 


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10This estimate is based on the average 

annualized cost for dentists that do not currently 

have an amalgam separator. See DCN DA00145. 

provide a method for addressing 

variations among products, processes, 

and other factors, which result in 

distinctly different effluent 

characteristics. See Texas Oil & Gas 

Ass’n. v. U.S. EPA, 161 F.3d 923, 939– 

40 (5th Cir. 1998). Regulation of a 

category by subcategories provides that 

each subcategory has a uniform set of 

effluent limitations or pretreatment 

standards that take into account 

technological achievability, economic 

impacts, and non-water quality 

environmental impacts unique to that 

subcategory. In some cases, effluent 

limitations or pretreatment standards 

within a subcategory may be different 

based on consideration of these same 

factors, which are identified in CWA 

section 304(b)(2)(B). The CWA requires 

EPA, in developing effluent guidelines 

and pretreatment standards, to consider 

a number of different factors, which are 

also relevant for subcategorization. The 

CWA also authorizes EPA to take into 

account other factors that the 

Administrator deems appropriate. 

In developing the proposed rule, EPA 

considered whether subcategorizing the 

dental industry was warranted. EPA 

evaluated a number of factors and 

potential subcategorization approaches, 

including the size of dental office, 

specialty practices, and unusual 

configurations that may be found at very 

large offices such as clinics and 

universities. EPA proposes that 

establishing formal subcategories is not 

appropriate for the Dental Amalgam 

category for three reasons. First, the 

proposed rule is structured to set 

standards only for those facilities that 

discharge dental amalgam. Second, the 

requirements do not include a size 

threshold because the technology is 

readily scaled to the size of the dental 

office. Finally, those states and localities 

that already have regulatory programs 

for controlling discharges of dental 

amalgam have been largely successful 

without subcategorization. 

XIV. Proposed Regulation 

A. PSES Options Selection 

Section XI discussed the technologies 

identified to control amalgam 

discharges from dental offices. EPA 

identified two basic technologies, 

amalgam separators and polishing. EPA 

determined separators plus polishing is 

not ‘‘available’’ as that term is used in 

the CCWA. 

EPA identified one technology that is 

available and demonstrated—amalgam 

separators. EPA further identified BMPs 

that would ensure the effectiveness of 

the amalgam separator technology and 

would reduce discharges of dental 

amalgam not captured by an amalgam 

separator. Therefore, EPA developed a 

regulatory option based on proper 

operation and maintenance of amalgam 

separators that achieve a 99.0% 

reduction of total mercury from 

amalgam process wastewater with 

BMPs. Compliance with the numeric 

pretreatment standard for new and 

existing sources could be met by 

installation and proper operation and 

maintenance of an amalgam separator 

certified to meet at least 99.0% 

reduction of total mercury according to 

the 2008 ISO 11143 standard. 

Compliance with two additional 

BMPs—not flushing scrap amalgam 

down the drain and cleaning of chair 

side traps with non-bleach, nonchlorine cleaners—are necessary to 

prevent mercury discharges that would 

bypass the separator. EPA finds that the 

proposed technology basis is 

‘‘available’’ as that term is used in the 

CWA because it is readily available and 

feasible for all dental offices. ADA 

recommends its dentists use the 

technology on which this rule is based 

(i.e., amalgam separators and BMPs). 

Further, EPA estimates that 40% of 

dental offices currently use amalgam 

separators on a voluntary basis or are in 

states with state or local laws requiring 

the use of amalgam separators. For those 

dental offices that have not yet installed 

an amalgam separator, EPA estimates 

this is a low cost technology with an 

approximate average annual cost of 

$700 10 per office. EPA’s economic 

analysis analyzes these costs in relation 

to the overall income of the regulated 

entities and shows that this proposed 

rule is economically achievable (see 

Section XVI). Finally, EPA also 

examined the non-water quality 

environmental impacts of the proposed 

rule and found them to be acceptable. 

See Section XX, ‘‘Non Water Quality 

Environmental Impacts.’’ 

EPA is not proposing to establish 

pretreatment standards based on 

technologies that remove dissolved 

mercury, or polishing. None of the states 

with mandated requirements to reduce 

dental mercury discharges requires 

polishing. EPA also lacks adequate 

performance data to truly assess the 

efficacy of polishing or its availability of 

ion exchange for nationwide use. EPA’s 

current information suggests that 

polishing only achieves incremental 

removals over the BAT selected 

technology of less than one half percent 

of total mercury. While even very small 

amounts of mercury have environmental 

effects, EPA lacks sufficient data to 

conclude that there is a significant 

difference in the performance between 

the two technologies. EPA estimates that 

the capital costs of amalgam separators 

and polishing are at least four times that 

of amalgam separators alone (see DCN 

DA00122). Finally, EPA is uncertain 

whether existing dental offices have 

adequate space to install polishing 

controls. These factors led EPA to find 

that polishing is not ‘‘available’’ as that 

term is used in the CWA. As a result, 

EPA did not select amalgam separators 

followed by polishing as the technology 

basis for this proposed rule. EPA solicits 

data on the costs, performance, 

affordability, and availability of 

polishing in combination with amalgam 

separators. 

B. Pollutants of Concern and Pass 

Through 

Of the dental amalgam constituents, 

mercury is of greatest concern to human 

health because it is a persistent, 

bioaccumulative, toxic chemical and 

can bioaccumulate three to ten times 

across each trophic level of the food 

chain. Mercury from dental amalgam 

makes its way into the environment 

when it is discharged from the dental 

facility to a POTW, where it settles into 

sewage sludge, or is discharged to 

surface waters. Once discharged, certain 

microorganisms change mercury into 

methylmercury, a form of mercury that 

can be absorbed by fish, shellfish and 

animals that eat fish. 

EPA finds that the technologies 

considered for control of amalgam 

solids will be similarly effective on 

other metals contained in dental 

amalgam because these metals are in a 

solids form, and the separation 

technology is designed to remove solids. 

Therefore any controls established for 

the reduction of mercury discharges will 

similarly reduce the discharge of other 

metals contained in amalgam. As such, 

EPA focused its consideration of 

regulated pollutants on mercury. 

C. POTW Pass Through Analysis 

To establish pretreatment standards, 

EPA examines whether the pollutants 

discharged by the industry ‘‘pass 

through’’ a POTW to waters of the U.S. 

or interfere with the POTW operation or 

sludge disposal practices. EPA’s 

consideration of pass through for 

national technology based categorical 

pretreatment standards differs from that 

described in Section VIII for general 

pretreatment standards. For categorical 

pretreatment standards, EPA’s approach 

for pass through satisfies two competing 

objectives set by Congress: (1) That 

standards for indirect dischargers be 


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11Best Practicable Control Technology Currently 

Available. 

12For all the metals contained in dental amalgam, 

EPA’s record demonstrates that these pollutants 

would similarly pass through as defined above. See 

the Pollutant Reduction Estimates section of the 

TEDD for POTW removal estimates for the other 

metals. 

13EPA recognizes that dentists, infrequently, may 

remove amalgam in the course of emergency 

treatment. EPA does not intend for discharges of 

dental amalgam, related to only these infrequent 

emergency treatments, to preclude such dentists 

from certifying. 

equivalent to standards for direct 

dischargers; and (2) that the treatment 

capability and performance of the 

POTWs be recognized and taken into 

account in regulating the discharge of 

pollutants from indirect dischargers. 

Generally, in determining whether 

pollutants pass through a POTW when 

considering the establishment of 

categorical pretreatment standards, EPA 

compares the percentage of the 

pollutant removed by typical POTWs 

achieving secondary treatment with the 

percentage of the pollutant removed by 

facilities meeting BAT effluent 

limitations. A pollutant is deemed to 

pass through a POTW when the average 

percentage removed by a typical POTW 

is less than the percentage removed by 

direct dischargers complying with 

BPT11/BAT effluent limitations. In this 

manner, EPA can ensure that the 

combined treatment at indirect 

discharging facilities and POTWs is at 

least equivalent to that obtained through 

treatment by a direct discharger, while 

also considering the treatment 

capability of the POTW. 

In the case of this proposed 

rulemaking, where only pretreatment 

standards are being developed, EPA 

compared the POTW removals with 

removals achieved by indirect 

dischargers using the candidate 

technology that otherwise satisfies the 

BAT factors. Historically, EPA’s primary 

source of POTW removal data is its 1982 

‘‘Fate of Priority Pollutants in Publicly 

Owned Treatment Works’’ (also known 

as the 50 POTW Study). The 50 POTW 

study presents data on the performance 

of 50 POTWs achieving secondary 

treatment in removing toxic pollutants. 

Results of this study demonstrate 

POTWs remove 90% of total mercury 

found in wastewater. EPA has data from 

targeted studies performed by NACWA 

and ADA that indicate a POTW can 

remove 95% of total mercury. However, 

these studies reflect the performance of 

best performing POTWs, as opposed to 

the 50 POTW Study which reflects 

nationwide POTWs. Consequently, for 

this proposal, EPA maintains a POTW 

percent removal rate of 90% for its 

nationwide pass-through analysis. In 

comparison, indirect dischargers using 

this proposed technology will remove 

99.0% or more total mercury prior to 

discharge. Therefore, EPA concludes 

mercury passes through 12 and is today 

proposing requirements to control its 

discharge. 

D. Requirements 

This proposed rule would establish a 

pretreatment standard that would 

require removal of at least 99.0% of total 

mercury from amalgam discharges and 

BMPs. One way affected dental offices 

would be able to meet the standard 

would be to use, and properly operate 

and maintain, a dental amalgam 

separator certified to achieve at least 

99.0% reduction of total mercury 

according to the 2008 ISO 11143 

standard, to perform certain BMPs, and 

to certify to this effect. Another way 

affected dental offices would be able to 

meet the standard would be to certify 

that they do not install or remove 

amalgam except in limited emergency 

circumstances. Dentists that certify that 

they do not install or remove amalgam 

will be exempt from any further 

requirements of the proposed rule. 

While the proposed rule does not 

require the use of an amalgam separator 

to meet the numeric standard, EPA 

expects that most, if not all dentists that 

place or remove amalgam would use 

this widely available technology to 

comply with the proposed numeric 

standard. EPA expects dentists will 

choose to install and operate an 

amalgam separator because of the nature 

of dental offices, the variability of the 

flows and resulting waste streams, and 

the difficulty in obtaining a sample that 

represents only dental amalgam 

discharges. Moreover, amalgam 

separators are an easy to use, low cost 

technology. Dental offices that elect to 

not use an amalgam separator must meet 

the proposed numeric limit and would 

be subject to the oversight and 

compliance requirements for indirect 

discharges subject to national 

pretreatment requirements. 

In selecting an amalgam separator that 

meets the requirements of today’s 

proposed pretreatment standards, 

dentists would verify that the amalgam 

separator is compliant with the 2008 

ISO 11143 standard and meets the 

design specifications of the proposed 

regulation for their configuration. Once 

selected and installed, EPA expects 

dentists will operate and maintain the 

separator following all manufacturer’s 

instructions and conduct inspections at 

least monthly to ensure all features are 

functional. 

This proposal would subject all 

dentists (except those specialists as 

described in Section XII) to categorical 

pretreatment requirements. EPA 

recognizes that some dentists covered 

by this proposal do not apply or remove 

dental amalgam except possibly in 

limited emergency circumstances. 

However, EPA, in consultation with 

pretreatment authorities, has been 

unable to identify a publically available 

source of information that differentiates 

dental offices on the basis of whether or 

not dental amalgam may reasonably be 

expected to be present. As such, this 

proposed rule would apply to such 

dischargers and require them to report 

baseline information, but it would also 

allow them to certify (at any time) that 

they do not and will not install or 

remove amalgam (not including 

infrequent emergency treatment as 

discussed below). This would fulfill 

their obligations under this proposed 

rule. If they subsequently elect to install 

or remove amalgam, they would then 

need to comply with the proposed 

numeric standard (e.g., proper operation 

and maintenance of an amalgam 

separator) and with the BMPs in this 

proposed rule.13

EPA does not want to penalize 

existing dental offices or institutional 

dental facilities that have already 

installed amalgam separators either 

voluntarily or to comply with state or 

local requirements. EPA recognizes that 

these offices may currently have 

amalgam separators in place that are 

certified to a removal rate slightly less 

than this proposed standard. For 

example, some states require dental 

offices to employ amalgam separators 

that are certified to remove 95% total 

mercury. EPA does not propose a rule 

that would require existing separators 

that still have a remaining useful life to 

be retrofitted with new separators, both 

because of the additional costs incurred 

by dental facilities that moved ahead of 

EPA’s proposed requirements to install 

a treatment technology and because of 

the additional solid waste that would be 

generated by disposal of the existing 

separators. Therefore, EPA is proposing 

that, as long as they continue to 

properly operate and maintain existing 

separators, comply with BMPs, and 

comply with recordkeeping 

requirements, these facilities would be 

considered in compliance with the 

numeric standard until ten years from 

the effective date of the final rule. EPA 

selected ten years because it appears to 

be a conservative estimate of the useful 

life of the existing equipment. However, 

if prior to that time, the currently 

installed separator needs to be replaced, 

these facilities would need to install and 


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14See Section XVI and the Economic Section of 

the Technical Development Document for 

information on how EPA annualized costs. 

operate an amalgam separator that meets 

a removal efficiency of 99.0%. 

EPA requests comment on this 

proposed regulatory scheme. In 

particular, EPA seeks comment on its 

approach for addressing offices where 

no dental amalgam is placed or removed 

except in limited emergency 

circumstances, and its approach for 

offices that have already installed an 

amalgam separator. 

E. PSNS Option Selection 

As previously noted, under section 

307(c) of the CWA, new sources of 

pollutants into POTWs must comply 

with standards which reflect the greatest 

degree of effluent reduction achievable 

through application of the best available 

demonstrated control technologies. 

Congress envisioned that new treatment 

systems could meet tighter controls than 

existing sources because of the 

opportunity to incorporate the most 

efficient processes and treatment 

systems into the facility design. EPA 

proposes PSNS that would control the 

same pollutants using the same 

technologies proposed for control by 

PSES. The technologies used to control 

pollutants at existing offices, amalgam 

separators and BMPs, are fully 

applicable to new offices. New dental 

offices can incorporate amalgam 

separators into the design and 

installation of their vacuum system. 

Furthermore, EPA has not identified any 

technologies that are demonstrated for 

new sources that are more effective than 

those identified for existing sources. 

Finally, EPA determined that the 

proposed PSNS present no barrier to 

entry. EPA has found that overall 

impacts from the proposed standards on 

new sources would not be any more 

severe than those on existing sources, 

since the costs faced by new sources 

generally will be the same as or less 

than those faced by existing sources. 

Therefore, EPA proposes to establish 

NSPS that are the same as those 

proposed for PSES. 

EPA does not propose to establish 

more stringent requirements for new 

sources based on technologies that 

remove dissolved mercury (i.e., 

polishing) for the same reasons stated 

above for existing standards. 

XV. Technology Costs 

This section summarizes EPA’s 

approach for estimating compliance 

costs, while the TEDD provides detailed 

information on the methodology. EPA’s 

cost methodology assumes dental offices 

would use the required BMPs in 

combination with 2008 ISO 11143 

amalgam separators on the market today 

to comply. See DCN DA00138. EPA 

categorized all of the costs as either 

capital costs 14 (one-time costs 

associated with planning or installation 

of technologies), as operation and 

maintenance (O&M) costs (costs that 

occur on a regular ongoing basis such as 

inspection or cleaning of the unit or 

annual purchases of amalgam 

cartridges), or as reporting costs. All 

final cost estimates are expressed in 

terms of 2010 dollars. 

EPA estimated compliance costs 

associated with this proposal using data 

collected through EPA’s Health Services 

Industry Detailed Study (August 2008) 

[EPA–821–R–08–014], a review of the 

literature, and information supplied by 

vendors. EPA’s cost estimates represent 

the incremental costs for a dental office 

to comply with this proposed rule. For 

costing purposes, EPA differentiated 

dental offices by those that already use 

amalgam separators and those that do 

not. 

EPA recognizes that some fraction of 

dental offices subject to this proposed 

rule may not place or remove amalgam 

and proposes to allow them to submit a 

one-time baseline monitoring report. 

Such dental offices would be exempt 

from this rule so long as they do not 

place or remove amalgam. Should the 

status of the dental office change, the 

certification would no longer be valid. 

For example, if a dental office so 

certifies and is sold, the new owner 

must similarly so certify or would need 

to comply with the rule. See § 441.10. 

EPA estimates the costs associated with 

this one-time only certification to be 

$22. 

In general, one approach that EPA 

takes to estimate compliance costs is to 

use facility-specific data to determine 

what requirements apply to a given 

facility and whether that facility would 

already meet the proposed 

requirements. This approach requires 

facility specific technical and financial 

data. In this case, EPA would need such 

data for approximately 110,000 dental 

offices estimated to be subject to this 

rule. Such data are not available. An 

alternative approach often used by EPA 

is to develop a series of model facilities 

that exhibit the typical characteristics of 

the affected facilities and calculate costs 

for each model facility. EPA can then 

determine how many of the affected 

facilities are represented nationally by 

each model facility to represent the full 

universe of affected facilities. 

A. Methodology for Developing Model 

Dental Office Costs 

EPA used the model approach to 

estimate costs for facilities that place or 

remove amalgam for this proposal. The 

model facility approach used in this 

effort involved calculating compliance 

costs for each of the size classes of 

dental offices described in Section IX of 

this preamble. In other words, EPA 

developed compliance costs for six 

models based on the number of chairs 

in an office. The ranges for each model 

are as follows: 1 to 2 chairs, 3 chairs, 4 

chairs, 5 chairs, 6 chairs, and 7+ chairs 

(average of 10 chairs). In addition to 

each of the size class models, EPA 

developed a model facility to represent 

very large offices such as clinics and 

universities. This is discussed 

separately in Section XV. B., below. 

EPA developed two sets of costs for 

each model: one for facilities that do not 

use an amalgam separator and one for 

facilities that do. For those that do not 

use an amalgam separator, EPA 

estimated capital costs and operation 

and maintenance costs. Capital costs 

include purchase of the separator and 

installation. Recurring costs include 

replacement of the cartridge, and 

operation and maintenance costs. A 

summary of costs for dental offices that 

do not currently use amalgam separators 

may be found in Tables XV–1 and 

XV–2. 

TABLE XV–1—SUMMARY OF ONE TIME MODEL FACILITY COSTS ($2010) FOR DENTAL OFFICES THAT DO NOT

CURRENTLY USE AMALGAM SEPARATORS

Cost element 

Number of chairs in the model dental office 

1 or 2 3, 4, or 5 15 6 7+ 

Separator Purchase ................................................................................. $502 $599 $1,058 $1,531 


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15EPA 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. 

16EPA 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. 

17EPA assumed the separator can be sized for 3, 

4, or 5 chairs, but has kept these three model office 

sizes distinct because the economic analysis 

evaluates different revenues for each of these sized 

offices. 

TABLE XV–1—SUMMARY OF ONE TIME MODEL FACILITY COSTS ($2010) FOR DENTAL OFFICES THAT DO NOT

CURRENTLY USE AMALGAM SEPARATORS—Continued 

Cost element 

Number of chairs in the model dental office 

1 or 2 3, 4, or 5 15 6 7+ 

Installation ................................................................................................ 250 250 250 250 

TABLE XV–2—SUMMARY OF ONE TIME MODEL FACILITY COSTS ($2010) FOR DENTAL OFFICES THAT DO NOT

CURRENTLY USE AMALGAM SEPARATORS

Cost element 

Number of chairs in the model dental office 

1 or 2 3, 4, or 5 16 6 7+ 

Replacement Parts .................................................................................. $195 $219 $430 $647 

O&M Including Recycling ........................................................................ 216 216 216 216 

For those facilities that already have 

an amalgam separator, EPA calculated 

costs for certain additional recurring 

operation and maintenance associated 

with the amalgam separator compliance 

option in this proposal. Recurring costs 

include replacement of the cartridge and 

operation and maintenance costs. A 

summary of these costs may be found in 

Table XV–3. This is a conservative 

approach to costing, however, because 

some of these facilities would 

presumably continue to operate and 

maintain the separators that they have 

already chosen or been required to 

install. 

TABLE XV–3—SUMMARY OF ANNUAL MODEL FACILITY COSTS ($2010) FOR DENTAL OFFICES THAT CURRENTLY USE

AMALGAM SEPARATORS

Cost element 

Number of chairs in the model dental office 

1 or 2 3, 4, or 5 17 6 7+ 

Replacement Parts .................................................................................. $98 $110 $215 $324 

O&M including recycling .......................................................................... 116 116 116 116 

In assessing the long term costs of rule 

compliance for these model facilities 

(those with and without existing 

separators), EPA estimated that 

amalgam separators would have a 

service life of 10 years, at which time 

the amalgam separators would need to 

be replaced. For the purposes of cost 

estimates for this proposal, EPA 

assumed that all offices regardless of the 

original technology in-place would 

incur the full cost of purchasing 

amalgam separators at the time of 

reinstallation. However, because various 

modifications needed by the office for 

initial amalgam separator installation 

would have already been completed, 

EPA has projected that amalgam 

separators replaced beyond year 10 

would be installed at one-half of the 

cost of the original installation. For 

example, EPA assumed plumbing 

modifications for initial installation 

would cost $250 per office, but that 

replaced equipment would cost $125 to 

install. EPA assumed that dental offices 

would continue to incur recurring 

expenses such as O&M in the same way 

as described for the initial installation. 

Finally, all dental offices subject to 

this proposed rule will also have 

reporting requirements and BMP 

requirements. EPA also included 

reporting costs for one-time preparation 

of a baseline report and initial 

compliance report and recurring costs 

associated with preparation of an 

annual certification statement. Section 

XI describes the BMPs in this proposal. 

EPA projects that there will be no 

incremental costs associated with these 

BMPs, because 1) costs for nonoxidizing, 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. 


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18For example, multiple offices located in a 

single building or complex may be able to share 

plumbing, vacuum systems, and may be able to 

install a larger separator rather than each office 

having its own separator. 

19See the TEDD for the reported analyses using 

a 7% discount rate. 

20Costs of the rule, from the standpoint of cost 

to society, include compliance costs and 

administrative costs to control authorities. Social 

costs would also incorporate any adjustment based 

on a quantity demand response to a change in price 

driven by a price change due to cost pass-through 

to consumers. For this analysis, EPA is not able to 

demonstrate an observable change in price for 

dental services, therefore no observable change in 

amount of visits (quantity demanded). Therefore 

EPA makes no adjustment to social costs based on 

a change in quantity. 

21EPA adjusted the 2007 Economic Census 

revenue values to reflect 2010 dollars. 

22As a point of clarification, for this proposal, 

social costs equal the sum of compliance costs and 

administrative costs. 

B. Methodology for Developing Costs for 

Institutional Facilities 

Institutional dental service facilities 

(e.g., clinics or dental schools), have a 

larger number of chairs than the typical 

dental office. For these institutional 

dental facilities, EPA developed a 

costing methodology based on the 

methodology for offices described 

above. For purposes of costs, EPA 

assumed the average institutional 

facility has 15 chairs. In the 

methodology described previously, the 

model practice with the largest number 

of chairs for which EPA developed cost 

information is the 7+ chair model with 

an average of 10 chairs. Scaling the 

information on costs for the 10 chair 

model facility to a 15 chair operation 

using a straight ratio yields costs at 

these institutional facilities at 1.5 times 

the costs estimated for the largest chair 

range shown in Table XV–1 and Table 

XV–2. These costs are likely overstated 

as they do not reflect opportunities the 

largest offices may have to share costs,18

and they do not assume any economies 

of scale. EPA solicits comment and data 

regarding EPA’s analysis of clinics and 

institutional facilities. 

XVI. Economic Impact Analysis 

This section summarizes EPA’s 

assessment of the costs and impacts of 

the proposed pretreatment standards on 

the regulated industry. 

A. Social Cost Estimates 

As described earlier in Section XIV of 

this preamble, EPA proposes PSES and 

PSNS based on a widely available 

technology, amalgam separator, and 

employment of BMPs. Section XV 

provides a detailed explanation of how 

EPA estimated compliance costs for 

model dental offices. As described 

there, EPA developed compliance costs 

for six models based on the number of 

chairs in an office. The ranges for each 

model are as follows: 1 to 2 chairs, 3 

chairs, 4 chairs, 5 chairs, 6 chairs, and 

7+ chairs (average of 10 chairs). In 

addition to each of the size class 

models, EPA developed a model facility 

to represent institutional facilities such 

as clinics and universities. 

For each model facility, EPA 

estimated compliance costs for dental 

offices that currently use a separator, 

those that do not have a separator in 

place, and those that certify that they do 

not place or remove amalgam. For those 

that do not currently use a separator, 

EPA estimated costs as either capital 

costs (one-time costs associated with 

planning or installation of technologies), 

as O&M costs (costs that occur on a 

regular ongoing basis such as inspection 

or cleaning of the unit, annual 

purchases of amalgam cartridges, and 

recycling), and as reporting costs. For 

those that use a separator 

(approximately 40% of dental offices as 

reported in Section VIII), EPA estimated 

O&M costs and reporting costs only. As 

applicable, EPA annualized the capital 

costs over a 20-year period at a discount 

rate of 3%19 and summed these costs 

with the O&M and reporting costs to 

determine an annual compliance cost 

estimate for each model facility. In order 

to develop a national estimate of social 

costs 20 based on these model facilities, 

EPA estimated the number of dental 

offices represented by each model 

facility. As explained in Section IX, EPA 

estimated the number of dental offices 

based on data from the 2007 Economic 

Census 21 describing the number of 

establishments in the Offices of Dentists 

NAICS (621210), and their annual 

revenue. Because reported 

establishments were described by their 

annual revenue and not number of 

chairs (the basis of model compliance 

costs), EPA used data from two surveys, 

a Colorado survey and an ADA survey, 

to correlate the estimated number of 

chairs per office to the revenue range of 

dental offices. Because EPA used two 

different data sources, results are 

presented as a range. Details of the 

relationship between chairs and revenue 

can be found in the TEDD. 

To estimate nationwide social costs, 

EPA multiplied the estimated total 

annualized costs of rule compliance for 

each model facility by the estimated 

number of dental offices represented by 

that model (i.e. with the indicated 

number of chairs and with/without 

existing amalgam separators). EPA also 

accounted for some dental offices that 

may not place or remove amalgam and 

assigned them costs only for a one-time 

baseline monitoring report. EPA then 

summed the values for each chair range 

over the number of chair ranges to yield 

the total estimated compliance cost. 

Similarly, EPA calculated costs for 

institutional facilities by multiplying 

the compliance cost for its model 

institutional facility by the number of 

estimated institutional facilities 

indicated in Section IX. Lastly, EPA 

estimated costs for control authorities 

for administering the Dental Amalgam 

Rule.22 Details of this cost analysis can 

be found in the TEDD. See Table XVI– 

1 for EPA’s estimate of nationwide 

annualized costs for each chair range 

represented by EPA’s model facilities as 

well as EPA’s estimate of total 

nationwide annualized costs for this 

proposed rule. 

TABLE XVI–1—TOTAL ANNUALIZED SOCIAL COSTS BY NUMBER OF CHAIRS

[Millions of 2010 dollars] 

Number of chairs 

Total annualized costs by chair size 1

Colorado survey ADA Survey 

1–2 chairs .................................................................................................................................................... $3.4 $4.4 

3 chairs ........................................................................................................................................................ 9.5 16.3 

4 chairs ........................................................................................................................................................ 11.0 

5 chairs ........................................................................................................................................................ 5.4 14.8 

6 chairs ........................................................................................................................................................ 4.7 

7+ chairs ...................................................................................................................................................... 9.5 12.8 

Large Dental Facilities ................................................................................................................................. 0.1 0.1 


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23Risk Management Association reports financial 

statement information received from lending 

institutions, for businesses in a wide range of 

economic sectors, including Dental Offices. These 

data include a wide range of income statement and 

balance sheet information as well as financial and 

operating ratios. 

TABLE XVI–1—TOTAL ANNUALIZED SOCIAL COSTS BY NUMBER OF CHAIRS—Continued 

[Millions of 2010 dollars] 

Number of chairs 

Total annualized costs by chair size 1

Colorado survey ADA Survey 

Cost to Control Authorities .......................................................................................................................... 0.9 0.9 

Total Annualized Social Costs ............................................................................................................. 44.5 49.4 

1EPA assumed that initial capital outlays and initial incurrence of ongoing compliance expenses would occur in the third year following rule 

promulgation. EPA assumed that the amalgam separator technology would have a service life of 10 years, and used a 20-year analysis period to 

allow for one-time replacement of capital equipment 10 years following the initial installation. A 3% discount rate was used for the analysis reported in this table, see the TEDD for the analysis with a 7% discount rate. 

B. Economic Impact Methodologies 

EPA devised a set of tests for 

analyzing economic achievability. As is 

often the practice, EPA conducted a 

cost-to-revenue analysis to examine the 

relationship between the costs of the 

proposed rule to current (or pre-rule) 

dental office revenues. In addition, EPA 

chose to examine the financial impacts 

of the proposed rule using two measures 

that utilize the data EPA has on dental 

office baseline assets and estimated 

replacement capital costs: (1) Ratio of 

the Proposed Rule’s Capital Costs to 

Total Dental Office Capital Assets and 

(2) Ratio of the Proposed Rule’s Capital 

Costs to Annual Dental Office Capital 

Replacement Costs. 

EPA did not conduct a traditional 

closure analysis for this proposed rule 

because EPA does not have detailed 

data on baseline financial conditions of 

dental offices. Also, closure analyses 

typically rely on accounting measures 

such as present value of after-tax cash 

flow. However, such accounting 

measures are difficult to implement for 

businesses that are organized as sole 

proprietorships or partnerships, as is the 

case in the dental industry. Still, the 

2007 Economic Census reports that 

approximately 700 offices of the 

approximately 110,000 total offices had 

revenue of less than $25,000 (2007 

dollar basis). In reviewing the implied 

operating characteristics of these low 

revenue offices, EPA considered 

whether these offices should be 

excluded from the analyses on any of 

the following bases: 

• These low revenue offices could be 

single-dentist and/or part-time 

businesses that provide services as a 

subcontractor on an independent feefor-service basis, such as dental hygiene, 

in general service dental offices that are 

owned and operated by a larger dental 

practice. Because these establishments 

would not be the primary owner/

operator of the dental offices in which 

they provide services, they would not 

directly incur the compliance costs of a 

Dental Amalgam Rule. If they incurred 

any of these costs, it would be on a 

limited fractional share basis, most 

likely in proportion to the total value of 

their services as a fraction of the total 

revenue in the office. On the other hand, 

if these operators offer their services in 

a competitive market, it may be that 

none of the compliance costs are shared 

by these subcontractors. 

• Another possibility is these very 

low revenue offices could be non-profit 

groups which provide pay-as-you-can or 

free services to a low-income 

populations. In this case, these small 

businesses may be viable enterprises 

because they receive in-kind donations 

not counted as revenue, e.g., services of 

a practicing dentist. 

• Alternatively, these low revenue 

offices may be non-viable as for-profit 

businesses, if they are attempting to 

operate as general service dental 

practices. This is based on EPA’s 

assessment (see Ratio of Proposed Rule 

Capital Costs to Total Dental Office 

Capital Replacement Costs, below) that 

1–2 chair offices would incur pre-rule 

capital replacement costs of 

approximately $23,500 per year. This 

cost represents all or a substantial 

fraction of annual revenue of the 

business in the below-$25,000 revenue 

range. Accordingly, these businesses 

may not be operating viably as for-profit 

general service dental offices. 

As such, EPA could consider these 

offices to be the equivalent of baseline 

closures as traditionally accounted for 

in cost and economic impact analysis 

for effluent guidelines rulemakings. As 

a result of the uncertainty here, EPA 

analyzed the impacts twice: (1) 

Excluding dental offices that could 

represent baseline closures and (2) 

including all offices in the analysis. EPA 

solicits comment for additional 

information on these low revenue dental 

offices. 

1. Cost-to-Revenue Analysis 

To provide an assessment of the 

impact of the rule on dental offices, EPA 

used a cost-to-revenue analysis as is 

standard practice for ELGs when 

looking at impacts to small businesses. 

The cost-to-revenue analysis compares 

the total annualized compliance cost of 

each regulatory option with the revenue 

of the entities. It is also used under the 

Regulatory Flexibility Act (RFA) to 

determine if a rule has the potential to 

have a significant impact on a 

substantial number of small entities. 

EPA apportioned all dental offices into 

Economic Census revenue ranges. Using 

the relationship between revenue and 

number-of-chairs previously developed, 

each revenue range was assigned to a 

number-of-chairs category which 

determined its annual costs. EPA looked 

at whether all, some, or none of the 

offices in each revenue range would 

exceed the 1% or 3% threshold (to 

signal the potential for significant 

impact), and summed across chair-size 

categories to assess impact to the 

industry. To incorporate the discussion 

of low revenue dental offices described 

in Section XVI.B above, this analysis is 

conducted twice: (1) Excluding dental 

offices that could represent baseline 

closures and (2) including all offices in 

the analysis. 

2. Ratio of the Proposed Rule’s Capital 

Costs to Total Dental Office Capital 

Assets 

This ratio examines the initial 

spending on capital costs of compliance 

in relation to the baseline value of assets 

on the balance sheet of dental office 

businesses. EPA assumes a low ratio 

implies limited impact on dental offices’ 

ability to finance the initial spending on 

capital costs of the proposed rule. A 

high ratio may still allow costs to be 

financed but could imply a need to 

change capital planning and budgeting. 

EPA relied on data from Risk 

Management Association (RMA) 23 to 

estimate the average asset-to-sales ratio 


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in each number-of-chairs category for 

the dental office sector. This ratio was 

then applied to the revenue range/

number-of-chairs categories to find an 

asset value for the minimum (reported 

as low in Table XVI–3) and maximum 

(reported as high in Table XVI–3) 

revenue values for that number-of-chairs 

category. EPA used these baseline assets 

by number-of-chairs category as the 

denominator for the ratio. Total 

proposed rule compliance costs, as 

described in Section XVI.B above, were 

assigned to each number-of-chairs 

category as the numerator for the ratio. 

To incorporate the discussion of low 

revenue dental offices described in 

Section XVI.B above, this analysis is 

conducted twice: (1) Excluding dental 

offices that could represent baseline 

closures, and (2) including all offices in 

the analysis. This analysis assumes a 

minimum revenue value of $5,000 for 

the lowest revenue range to prevent 

division by zero. 

The RMA data contains the limitation 

that it may not be fully representative of 

all dental offices, because it only 

represents dental offices that are 

successful borrowers. It is possible that 

offices that are not financially healthy 

may be underrepresented in the RMA 

data. This would tend to understate 

EPA’s finding of impacts. 

3. Comparison of the Proposed Rule’s 

Capital Costs to Annual Dental Office 

Capital Replacement Costs 

EPA also compared the initial 

spending on capital costs of compliance 

associated with this proposed rule to the 

estimated capital replacement costs for 

a dental office business (e.g., computer 

systems, chairs, x-ray machines, etc.). 

The capital replacement costs represent 

a value that dental offices may 

reasonably expect to spend in any year 

to replace and/or upgrade dental office 

capital equipment. EPA assumes a low 

ratio implies limited impact on dental 

offices’ ability to finance the initial 

spending on capital costs of the 

proposed rule. A high ratio may still 

allow costs to be financed but could 

imply a need to change capital planning 

and budgeting. However, because EPA 

expects that annual dental office capital 

replacement would be smaller than total 

dental office capital assets, this ratio is 

likely to result in a higher value than 

the previous ratio. Because this ratio is 

based on a different data source, it 

provides an independent check that 

abstracts from the limitations of the 

RMA data. 

EPA used data from Safety Net Dental 

Clinic Manual, prepared by the National 

Maternal & Child Oral Health Resource 

Center at Georgetown University (see 

DCN DA00143). This study examines 

data describing the equipment needs 

and costs for starting a dental practice 

for a range of different number-of-chairs 

including information on the life of the 

dental equipment. EPA then used these 

data to estimate capital replacement 

costs, accounting for the total value of 

equipment purchases for different 

numbers of chairs, and the composition 

of purchases by equipment life category. 

EPA used these replacement capital 

costs by number-of-chairs as the 

denominator for the ratio. Total 

proposed rule compliance costs, as 

described in Section XVI.B above, were 

assigned to each number-of-chairs as the 

numerator for the ratio. 

Because the data are for starting a 

dental clinic instead of a dental 

practice, EPA is taking comment to 

solicit additional information on 

equipment needs and costs for starting 

a dental practice, including information 

on the life of the dental equipment. See 

the TEDD for details on this analysis. 

C. Results of Impact Analysis 

1. Cost-to-Revenue Analysis Results 

Following the methodology outlined 

in XVI.B, EPA estimated the occurrence 

of annualized compliance costs 

exceeding the 1% and 3% of revenue 

thresholds for the proposed option 

twice: (1) Excluding dental offices that 

could represent baseline closures, and 

(2) including all offices in the analysis. 

Table XVI–2 summarizes the results 

from this analysis. As shown there, 

under either scenario, over 99% of 

dentists would incur annualized 

compliance costs of less than 1% of 

revenue. With baseline set-asides 

excluded from the analysis, 507 offices 

(0.5% of offices using dental amalgam 

and exceeding the set-aside revenue 

threshold) are estimated to incur costs 

exceeding 1% of revenue; no offices are 

estimated to incur costs exceeding 3% 

of revenue. With baseline set-asides 

included in the analysis, 965 offices 

(0.9% of offices using dental amalgam) 

are estimated to incur costs exceeding 

1% of revenue; 221 offices (0.2% of 

offices using dental amalgam) are 

estimated to incur costs exceeding 3% 

of revenue. 

TABLE XVI–2—COST-TO-REVENUE ANALYSIS IMPACT SUMMARY

Number of chairs Total offices 

by chair size 

Costs >1% Revenue Costs >3% Revenue 

Number Percent Number Percent 

Excluding Baseline Set-Aside Offices from Analysis 

1–2 chairs ............................................................................ 12,197 507 4.2 0 0.0 

3 chairs ................................................................................ 25,835 0 0.0 0 0.0 

4 chairs ................................................................................ 27,976 0 0.0 0 0.0 

5 chairs ................................................................................ 15,194 0 0.0 0 0.0 

6 chairs ................................................................................ 12,047 0 0.0 0 0.0 

7+ chairs .............................................................................. 16,611 0 0.0 0 0.0 

Total .............................................................................. 109,859 507 0.5 0 0.0 

Including Baseline Set-Aside Offices in Analysis 

1–2 chairs ............................................................................ 12,197 965 7.9 221 1.8 

3 chairs ................................................................................ 25,835 0 0.0 0 0.0 

4 chairs ................................................................................ 27,976 0 0.0 0 0.0 

5 chairs ................................................................................ 15,194 0 0.0 0 0.0 

6 chairs ................................................................................ 12,047 0 0.0 0 0.0 

7+ chairs .............................................................................. 16,611 0 0.0 0 0.0 


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TABLE XVI–2—COST-TO-REVENUE ANALYSIS IMPACT SUMMARY—Continued 

Number of chairs Total offices 

by chair size 

Costs >1% Revenue Costs >3% Revenue 

Number Percent Number Percent 

Total .............................................................................. 109,859 965 0.9 221 0.2 

Source: EPA analysis. 

2. Ratio of the Proposed Rule’s Capital 

Costs to Total Dental Office Capital 

Assets 

Table XVI–3 reports the findings from 

this analysis, specifically the weighted 

average of the initial spending on the 

proposed rule’s capital costs divided by 

total assets of dental office across the 

revenue range/number-of-chairs 

analysis combinations. With baseline 

set-asides excluded from the analysis, 

the resulting initial capital costs to total 

capital assets values are low, with an 

average value 0.5% to 1.0% for the no 

technology in-place case and 0% for the 

technology in-place case. With baseline 

closures included in the analysis, the 

resulting initial capital costs to total 

capital assets values are low, with an 

average value 0.6% to 1.2% for the no 

technology in-place case and 0% for the 

technology in-place case. 

TABLE XVI–3—INITIAL SPENDING AS PERCENTAGE OF PRE-RULE TOTAL DENTAL OFFICE CAPITAL ASSETS 1

Number of chairs 

Technology in place No technology in place 

Low High Low High 

Excluding Baseline Set-Aside Establishments from Analysis 

1–2 chairs ........................................................................................................................ 0.1 0.1 2.7 1.3 

3 chairs ............................................................................................................................ 0.0 0.0 0.8 0.5 

4 chairs ............................................................................................................................ 0.0 0.0 0.5 0.3 

5 chairs ............................................................................................................................ 0.0 0.0 0.3 0.2 

6 chairs ............................................................................................................................ 0.0 0.0 0.3 0.2 

7+ chairs .......................................................................................................................... 0.0 0.0 0.2 0.2 

Weighted Average ........................................................................................................... 0.0 0.0 0.7 0.4 

Including Baseline Set-Aside Establishments in Analysis 

1–2 chairs ........................................................................................................................ 0.2 0.1 3.7 1.7 

3 chairs ............................................................................................................................ 0.0 0.0 0.8 0.5 

4 chairs ............................................................................................................................ 0.0 0.0 0.5 0.3 

5 chairs ............................................................................................................................ 0.0 0.0 0.3 0.2 

6 chairs ............................................................................................................................ 0.0 0.0 0.3 0.2 

7+ chairs .......................................................................................................................... 0.0 0.0 0.2 0.2 

Weighted Average ........................................................................................................... 0.0 0.0 0.8 0.5 

1EPA used the baseline asset value for the minimum (reported as low) and maximum (reported as high) revenue values by number-of-chairs 

category as the denominator for the ratio. Total proposed rule compliance costs, as described in Section XVI.B above, were assigned to each 

number-of-chairs category as the numerator for the ratio. 

3. Ratio of the Proposed Rule’s Capital 

Costs to Annual Dental Office Capital 

Replacement Costs Results 

EPA compared the estimated total 

initial spending on the proposed rule’s 

capital costs to the estimated capital 

replacement costs across all chair-sizes. 

The resulting values for the proposed 

option range from 2.9% to 3.5%, with 

a weighted average of 2.9% across all 

chair size ranges. 

TABLE XVI–4—INITIAL SPENDING AS

PERCENTAGE OF ESTIMATED ANNUAL DENTAL OFFICE CAPITAL REPLACEMENT COSTS 1

Number of chairs Percent 

1–2 chairs ................................. 3.4 

3 chairs ..................................... 3.2 

4 chairs ..................................... 2.6 

5 chairs ..................................... 2.2 

TABLE XVI–4—INITIAL SPENDING AS

PERCENTAGE OF ESTIMATED ANNUAL DENTAL OFFICE CAPITAL REPLACEMENT COSTS 1—Continued 

Number of chairs Percent 

6 chairs ..................................... 2.9 

7 chairs ..................................... 3.5 

8 chairs ..................................... 3.1 

9 chairs ..................................... 2.9 

Weighted Average .................... 2.9 

Source: EPA Analysis. 

1EPA estimated capital replacement costs, 

accounting for the total value of equipment 

purchases for different numbers of chairs, and 

the composition of purchases by equipment 

life category by number-of-chairs as the denominator for the ratio. Total proposed rule 

compliance costs, as described in Section 

XVI.B, were assigned to each number-ofchairs as the numerator for the ratio. 

D. Economic Achievability 

The analyses performed above 

demonstrate the impact of this proposed 

rule on the dental office sector. In the 

cost-to-revenue analysis, EPA found that 

no more than 0.2% of offices, mostly in 

the lower revenue ranges, would 

potentially incur costs in excess of 3% 

of revenue. The two financial ratios 

reported in Tables XVI–3 and XVI–4 

show that the proposed option would 

not cause dental offices to encounter 

difficulty in financing initial spending 

on capital costs of the proposed 

regulatory option. Based on the results 

of the three analyses above in 

combination, and EPA’s inability at this 

time to conduct a traditional facility 

closure analysis, EPA has determined 

that the proposed pretreatment standard 

is economically achievable. EPA notes 

that, due to a lack of data, the economic 


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24Because this approach is based on the number 

of dentists, it includes those dentists both at offices 

and institutional facilities. 25 71 million restorations times 31 mg per 

restoration. 

26 It also contains small amounts of indium and 

palladium. EPA did not estimate discharges of these 

two pollutants. 

impact analyses did not include large 

institutional facilities. However, the 

results of the economic analyses 

performed on a range of office sizes 

indicate that this proposal is 

economically achievable at every level. 

Therefore, EPA projects the rule would 

similarly be achievable for large 

institutional facilities. EPA requests 

comment on this projection and data to 

perform economic achievability 

analyses. 

E. Economic Impact for New Sources 

EPA determined that this proposed 

pretreatment standard for new sources 

would not impose a barrier to entry. 

EPA relied on data describing the 

equipment needs and costs for starting 

a dental practice as compiled in Safety 

Net Dental Clinic Manual, prepared by 

the National Maternal & Child Oral 

Health Resource Center at Georgetown 

University (see DCN DA00143). 

Information from the Georgetown 

Manual demonstrates that the amalgam 

separator capital costs (based on costs 

for existing model facilities as described 

in Section XI) comprised 0.3% to 0.4% 

of the cost of starting a dental practice 

and, therefore, does not pose a barrier to 

entry. 

TABLE XVI–5—INITIAL SPENDING AS

PERCENTAGE OF ESTIMATED DENTAL

OFFICE START-UP COSTS

Number of chairs Percent 

1–2 chairs ................................. 0.4 

3 chairs ..................................... 0.4 

4 chairs ..................................... 0.3 

5 chairs ..................................... 0.3 

6 chairs ..................................... 0.3 

7 chairs ..................................... 0.4 

8 chairs ..................................... 0.4 

9 chairs ..................................... 0.3 

Weighted Average .................... 0.3 

Source: EPA Analysis. 

XVII. Pollutant Reductions to POTWs 

and Surface Waters 

Consistent with its costing 

methodology, EPA’s pollutant reduction 

methodology assumes 2008 ISO 11143 

amalgam separators on the market today 

with BMPs, the proposed technology 

basis, would be used to comply with 

this proposed rule. As was the case for 

costing, EPA does not have office 

specific discharge data for the 

approximately 110,000 dental offices 

potentially subject to this proposal. 

Instead, EPA has modeled the 

discharges of mercury based on 

nationwide estimates of amalgam 

restorations and removals, and did not 

calculate the pollutant reductions on a 

per office basis. Rather, EPA calculated 

average mercury loadings by dividing 

the total number of annual procedures 

by the total number of dentists 

performing the procedure.24 This is the 

same approach and data that EPA 

presented in its Health Services 

Industry Detailed Study (EPA 821–R– 

08–014). EPA did not receive comments 

on this part of the health study that 

would cause EPA to reconsider its 

approach, and, therefore, EPA did not 

change the overall methodology. The 

following sections describe the method 

in more detail. 

A. Nationwide Estimate of Annual 

Mercury Discharges From Dental Offices 

First, EPA estimated the amount of 

mercury potentially discharged 

nationwide through amalgam 

restorations. EPA’s main source of the 

data underlying all of the estimates 

related to restorations is Vandeven and 

McGinnis, 2005 (DCN 00163). EPA 

estimates 71 million restorations occur 

at dental offices annually and that these 

restorations are performed with one 

amalgam capsule per restoration. Each 

amalgam capsule contains 450 mg of 

mercury and, on average, 75% of the 

capsule is used for the filling, with the 

remaining 25% remaining in the 

capsule. Therefore, 340 mg of mercury 

(75% of the capsule) are used per filling. 

Further, 9% of the 340 mg of mercury, 

or 31 mg, is discharged to the POTW as 

carvings and filings or other waste. 

Thus, EPA estimates a total of 2.4 tons 

of mercury nationwide 25 is discharged 

annually to POTWs from restorations. 

Second, EPA modeled mercury 

discharges from amalgam removals. 

Similar to restorations, EPA’s main 

source of the data underlying all of the 

estimates related to amalgam removals 

is Vandeven and McGinnis, 2005. Based 

on this information, EPA estimates 

approximately 97 million amalgam 

removals occur each year. An average of 

300 mg mercury is removed from the 

filling. Ninety percent of the removed 

filling is assumed to be discharged to 

wastewater, and the other 10% is 

handled as dry waste and/or gray 

bagged. Thus, EPA estimates 29 tons of 

mercury are discharged to POTWs from 

removals each year. 

Summing the total mercury 

discharged from restorations plus that 

associated with filling removals, 31.4 

tons of mercury are potentially 

discharged annually to POTWs from 

dental offices. However, these 

calculations do not account for the 

amount of mercury removed at the 

dental office and prior to POTW 

discharge through existing chair side 

traps, vacuum pump filters, and/or 

amalgam separators as described below. 

B. National Estimate of Annual Baseline 

Discharges of Mercury From Dental 

Offices to POTWs 

As described in Section VIII, EPA 

estimates that 40% of dental offices 

currently operate dental amalgam 

separators. Thus, on a nationwide basis, 

approximately 65,000 dental offices 

currently do not have separators and 

44,000 offices already have separators in 

place. Of the offices that do not 

currently have separators in place, EPA 

assumed that 20% do not install or 

remove amalgam, but EPA requests 

comment on this assumption. For the 

remainder, based on information in its 

record, EPA assumes all offices have 

chair side traps or a combination of 

chair side traps and vacuum filters that 

result in 68% and 78% collection of 

dental amalgam, respectively (Vandeven 

and McGinnis). After accounting for 

mercury reductions achieved through 

existing chair side traps, vacuum filters, 

and separators, as appropriate, EPA 

estimates the offices without separators 

that place or remove amalgam 

collectively discharge a total of 4.4 tons 

of mercury to POTWs per year. The 

offices with separators collectively 

discharge approximately 63 pounds of 

mercury to POTWs per year. Thus, EPA 

calculates the current nationwide 

annual baseline pounds of mercury 

discharged to POTWs from dental 

offices to be 4.4 tons mercury (out of a 

total of the 31.4 tons mercury originally 

generated). See Chapter 10 of the TEDD 

for more information. 

C. National Estimate of Annual Baseline 

Discharges of Other Metals Contained in 

Amalgam From Dental Offices to 

POTWs 

Amalgam is comprised of roughly 

49% mercury, 35% is silver, 9% tin, 6% 

copper and 1% zinc 26 (DCN DA00131). 

As explained earlier in Section XI, EPA 

concludes the technology basis for this 

proposal would be equally effective in 

reducing discharges of silver, tin, 

copper, and zinc as it is in reducing 

mercury. EPA similarly assumes chair 

side traps and the combination of chair 

side traps and vacuum filters will result 

in 68% and 78% collection of these 

metals, respectively. Accordingly, after 

accounting for existing technologies at 

dental offices, EPA estimates that in 


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27 Dissolved mercury accounts for a portion of 

surface water discharges, because amalgam 

separators do not remove dissolved mercury. 

addition to 4.4 tons of mercury, 

approximately 4.6 tons of these 

additional metals are discharged to 

POTWs annually for a total metal 

discharge to POTWs of 9 tons annually. 

D. National Estimate of Annual 

Pollutant Reductions to POTWs 

Associated With This Proposal 

1. Mercury 

EPA estimates the 52,000 offices that 

install separators would obtain an 

additional 99.0% removal by amalgam 

separator (median removal efficiency of 

amalgam separators; see 7.1 of TEDD). 

This would result in reduction of total 

mercury discharges to POTWs by 4.3 

tons. Because dissolved mercury 

accounts for much less than 1% of total 

mercury (DCN DA00018), and because 

amalgam separators are not effective in 

removing dissolved mercury, the 

dissolved mercury contribution and 

associated reduction in loads is 

assumed to be negligible. EPA solicits 

comment and data on this assumption. 

2. Other Metals 

As explained earlier in Section XI, 

EPA concludes the technology basis for 

this proposal would be equally effective 

in reducing discharges of silver, tin, 

copper, and zinc as it is in reducing 

mercury. Accordingly, EPA estimates a 

reduction of these metal discharges to 

POTWs of approximately 4.5 tons. 

3. Total Reductions 

EPA estimates this proposal would 

annually reduce mercury discharges by 

4.3 tons and other metal discharges by 

4.5 tons for a total annual reduction to 

POTWs of 8.8 tons. 

E. National Estimate of Annual 

Pollutant Reductions to Surface Waters 

Associated With This Proposal 

In order to evaluate final discharges of 

mercury (and other metals) to waters of 

the U.S. by the POTW, EPA used its 50 

POTW Study to calculate POTW 

removals of each metal. As explained 

above, at baseline and prior to 

implementation of this proposal, EPA 

estimates 4.4 tons of dental mercury is 

collectively discharged annually to 

POTWs. Based on the 50 POTW Study, 

EPA estimates POTWs remove 90% of 

the 4.4 tons mercury from the 

wastewater. Thus, POTWs collectively 

discharge 880 lbs of mercury from 

dental amalgam to surface waters 

annually. Under this proposed rule, 

99.0% of the solid mercury currently 

discharged annually to POTWs will be 

removed prior to the POTW. The 

POTWs then further remove 90% of 

total mercury from the wastewater. This 

reduces the total amount of dental 

mercury discharged from POTWs 

nationwide to surface water to 14 lbs of 

mercury annually. In other words, 

discharges of mercury to waters of the 

U.S. are expected to be reduced by 860 

pounds per year.27 Similarly, EPA’s 50 

POTW Study data shows 79% to 88% 

of other metals in the wastewater are 

removed by POTWs. As explained 

above, EPA estimates 4.6 tons of other 

metals are also collectively discharged 

annually to POTWs. Thus POTWs 

collectively discharge approximately 

1,280 lbs of other metals to surface 

waters annually. Following compliance 

with this proposed rule, the total 

amount of other metal discharges from 

POTWs nationwide to surface waters 

will be approximately 20 lbs or a 

reduction of 1,257 lbs. See TEDD for 

more details. 

XVIII. Cost Effectiveness 

EPA also conducted an analysis of the 

cost-effectiveness of the proposed 

option. For more information about the 

methodology, data, and results see the 

cost effectiveness section of the TEDD. 

The results of this cost-effectiveness 

analysis are expressed in terms of the 

costs (in 1981 dollars) per poundequivalent removed, where poundsequivalent removed for a particular 

pollutant is determined by multiplying 

the number of pounds of a pollutant 

removed by an option by a toxic 

weighting factor (TWF). The toxic 

weighting factors account for the 

differences in toxicity among pollutants 

and are derived using chronic aquatic 

life criteria (or toxic effect levels) and 

human health criteria (or toxic effect 

levels) established for the consumption 

of fish. For this proposal, EPA used the 

annual pounds removed for mercury, 

silver, tin, copper and zinc. The TWF 

for these pollutants is shown in Table 

XVIII–1. 

TABLE XVIII–1—TOXIC WEIGHTING

FACTORS FOR POLLUTANTS IN DENTAL AMALGAM

Total Mercury ................................ 117.12 

Silver ............................................. 16.47 

Tin ................................................. 0.30 

Copper .......................................... 0.63 

Zinc ............................................... 0.05 

EPA presents cost effectiveness in 

1981 dollars as a reporting convention. 

This allows EPA to compare the costeffectiveness of various ELGs. EPA 

calculates cost-effectiveness as the ratio 

of pre-tax annualized costs of an option 

to the annual pounds-equivalent 

removed by that option, and for this 

proposal is expressed as the average 

cost-effectiveness for the option. 

Average cost-effectiveness can be 

thought of as the ‘‘increment’’ between 

no regulation and the selected option for 

any given rule. The technology basis for 

PSES in this proposal has a costeffectiveness ratio of $181–$201/lbequivalent. This cost-effectiveness ratio 

falls within industry comparisons of 

PSES cost-effectiveness. A review of 

approximately 25 of the most recently 

promulgated or revised categorical 

pretreatment standards demonstrates 

that PSES cost effectiveness ranges from 

approximately $1/lb-equivalent 

(Inorganic Chemicals) to $380/lbequivalent (Transportation Equipment 

Cleaning) in 1981 dollars. 

TABLE XVIII–2—PSES COST EFFECTIVENESS ANALYSIS

Proposed option 

Pre-tax total 

annualized costs 

($1981 M) 

Removals 

(lbs-eq) 

Average cost 

effectiveness 

ADA National Survey ............................................................................................................. $23 113,152 $201 

Colorado Survey .................................................................................................................... 21 113,152 181 


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XIX. Environmental Assessment 

A. Environmental Impacts 

EPA conducted a literature review 

concerning potential environmental 

impacts associated with mercury in 

dental amalgam discharged to surface 

water by POTWs. See DCN DA00148. 

Studies indicate that dental offices are 

the largest source of mercury entering 

POTWs. The total annual baseline 

discharge of dental mercury to POTWs 

is approximately 8,800 pounds (4.4 

tons): 8,448 pounds are in the form of 

solid particles and 352 pounds (4%) are 

dissolved in the wastewater. Through 

POTW treatment, approximately 90% of 

dental mercury is removed from the 

wastewater and transferred to sewage 

sludge. The 10% of dental mercury not 

removed by POTW treatment is 

discharged to surface water. EPA 

estimates that POTWs annually 

discharge approximately 880 pounds of 

dental mercury nationwide. 

The CWA regulations known as 

Standards for Use and Disposal of 

Sewage Sludge, 40 CFR part 503, control 

the land application, surface disposal, 

and incineration of sewage sludge 

generated by POTWs. Of the 11.2 billion 

dry pounds of sewage sludge generated 

annually, about 60%, or 6.7 billion 

pounds, are treated to produce biosolids 

for beneficial use as a soil amendment 

and applied to about 0.1% of 

agricultural lands in the United States 

(National Research Council, 2002). 

Approximately 4,800 pounds per year of 

dental mercury are contained in land 

applied biosolids. 

Approximately 18%, or 2 billion 

pounds, of the sewage sludge generated 

annually by POTWs are surface 

disposed in facilities such as sewage 

sludge mono-fills or municipal landfills. 

Approximately 1,400 pounds per year of 

dental mercury are contained in surface 

disposed sewage sludge. Pollutant limits 

and monitoring requirements for surface 

disposed sewage sludge mono-fills are 

set by 40 CFR part 503 and by 40 CFR 

part 258 for municipal landfills. There 

may be additional state or local 

regulations that are more stringent than 

the federal biosolids regulations. 

The remaining 22%, or 2.5 billion 

pounds, of sewage sludge generated 

annually by POTWs is disposed of 

through incineration. An estimated 35 

pounds of dental mercury are emitted to 

the atmosphere annually from 

incineration of sewage sludge (U.S. 

EPA, 2005); about 11.5 pounds of which 

are deposited within the conterminous 

United States (U.S. EPA, 1997). 40 CFR 

part 503, subpart E sets requirements for 

the incineration of mercury and other 

toxic metals in sludge. For mercury, 

subpart E provides that incineration of 

sludge must meet the requirements of 

the National Emissions Standards for 

Mercury in subpart E of 40 CFR part 61. 

Environmental assessment of impacts 

associated with POTW discharges of 

dental mercury is complicated by 

uncertainties about the fate and 

transport of mercury in aquatic 

environments. The elemental form of 

mercury used in dentistry has low water 

solubility and is not readily absorbed 

when ingested by humans, fish, or 

wildlife. However, elemental mercury 

may be converted into highly toxic 

methylmercury in aquatic environments 

by certain forms of anaerobic sulfur 

reducing bacteria. Methylmercury is 

easily absorbed into muscle and fat 

tissues, but it is not readily excreted due 

to its low water solubility. 

Methylmercury thus has high potential 

to become increasingly concentrated up 

through aquatic food chains as larger 

fish eat smaller fish. Fish commonly 

eaten by humans may have 

methylmercury levels 100,000 times 

that of ambient water. The neurological 

effects of consumption of 

methylmercury contaminated fish are 

well documented. Developmental 

effects to fetuses, infants, children, and 

women of childbearing age are of 

special concern. Neurological effects 

from predation of methylmercury 

contaminated fish have been 

documented to occur in wild 

populations of fish, birds, and mammals 

in many areas of the United States. 

A plausible link has been identified 

between anthropogenic sources of 

mercury in the United States and 

methylmercury in fish. However, fish 

methylmercury concentrations also 

result from existing background 

concentrations of mercury which may 

consist of mercury from natural sources, 

mercury re-emitted from the oceans or 

soils, and mercury deposited in the 

United States from sources in other 

countries. Given the current scientific 

understanding of the environmental fate 

and transport of mercury, it is not 

possible to quantify how much of the 

methylmercury in fish consumed by the 

U.S. population is contributed by U.S. 

emissions relative to international 

mercury sources or natural mercury 

sources. 

EPA was unable to assess the specific 

environmental impacts of dental 

mercury discharged by POTWs due to 

insufficient data needed to evaluate 

several fundamental factors about the 

discharge, fate, and transport of dental 

mercury in aquatic environments, 

including: the degree and geographic 

extent of dental mercury methylation in 

aquatic environments, the amount of 

methylated dental mercury that is taken 

up by fish and wildlife, the human 

consumption rates of fish contaminated 

with methylated dental mercury, and 

the extent and magnitude of naturallyoccurring mercury in aquatic 

environments. 

B. Environmental Benefits 

While EPA did not perform an 

environmental benefits analysis of this 

proposed rule, due to insufficient data 

about the aquatic fate and transport of 

dental mercury discharged by POTWs, 

EPA was able to assess the qualitative 

environmental benefits based on 

existing information. For example, EPA 

identified studies that show that 

decreased point-source discharges of 

mercury to surface water result in lower 

methylmercury concentrations in fish. 

Moreover, several studies quantified 

economic benefits from improved 

human health and ecological conditions 

resulting from lower fish concentrations 

of methylmercury. See DCN DA00148. 

The proposed pretreatment standards 

will produce human health and 

ecological benefits by reducing the 

estimated annual nationwide POTW 

discharge of dental mercury to surface 

water from 880 pounds to 14 pounds. 

XX. Non-Water Quality Environmental 

Impacts Associated With the Proposed 

Technology Basis 

Eliminating or reducing one form of 

pollution may cause other 

environmental problems. Sections 

304(b) and 306 of the Clean Water Act 

require EPA to consider non-water 

quality environmental impacts 

(including energy requirements) 

associated with effluent limitations 

guidelines and standards. To comply 

with these requirements, EPA 

considered the potential impact of the 

collection and treatment technologies 

on energy consumption, air pollution, 

and solid waste generation. EPA 

anticipates that the proposed rule would 

produce minimal non-water quality 

impacts. The Administrator has 

determined that these very minimal 

impacts are acceptable. For additional 

information on the analysis of these 

non-water quality impacts, see the 

Technical and Economic Development 

Document. 

A. Energy Requirements 

Net energy consumption considers the 

incremental electrical requirements 

associated with operating and 

maintaining dental amalgam separators 

used in combination with BMPs that 

form the technology basis for the 

proposed rule standards. As described 

in Section VI, an amalgam separator in 


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a dental office is installed between 

chairs used for treatment and the 

vacuum pump. Amalgam separators use 

sedimentation, either alone or in 

conjunction with filtration to remove 

solids in the waste stream. Most 

separators rely on gravity or the suction 

of the existing vacuum system to 

operate, and do not require an 

additional electrical power source. As a 

result, EPA expects operation of an 

amalgam separator would pose 

negligible additional energy 

requirements on the existing vacuum 

pump. 

While the vendor data used to support 

this proposed rule have not identified 

incremental energy requirements for an 

amalgam separator, EPA is aware that 

some units described in the literature 

may require small pumps to remove 

settled effluent from the separator (DCN 

00162). EPA found that these pumps are 

designed to operate only at the end of 

the day or overnight, when the vacuum 

system is turned off. Any incremental 

energy requirements in those cases 

where a small supplemental pump is 

installed would be negligible compared 

to the energy demands of the vacuum 

pump. Based on this evaluation of 

energy requirements associated with 

this proposed rule, EPA concludes there 

will be no significant non-water quality 

impacts associated with the energy 

requirements of this proposed rule. 

B. Air Emissions 

Unbound mercury is highly volatile 

and can easily evaporate into the 

atmosphere. An estimated 99.6% of 

dental mercury discharges are in solid 

bound form; i.e. elemental mercury 

bound to amalgam particles (DCN 

DA00018). Because the majority of 

dental mercury is bound to solid 

particles, it likely will not volatize to 

the atmosphere. Therefore, EPA expects 

the proposed PSES and PSNS will not 

pose any increases in air pollution. EPA 

concludes there will be no significant 

non-water quality impacts associated 

with air emissions as a result of this 

proposed rule. 

C. Solid Waste Generation 

As explained above in Section XI, in 

the absence of amalgam separators, a 

portion of the amalgam rinsed into chair 

side drains is collected by chair side 

traps. The remainder is discharged to 

the POTW where the vast majority is 

removed from the wastewater and 

becomes part of the POTW sludge that 

may be land applied, disposed of in 

landfills or mono-fills, or incinerated. 

This proposed rule is expected to 

increase the use of amalgam separators 

nationwide by one and a half times, 

since EPA estimates 40% of dental 

offices have separators installed, with a 

corresponding increase in collection of 

used amalgam prior to POTW discharge 

and recycling of amalgam via the spent 

separator canisters. EPA expects the 

operation and maintenance 

requirements associated with the 

amalgam separator compliance option 

included as part of the proposed rule 

will further promote recycling as the 

primary means of amalgam waste 

management. EPA expects this proposed 

rule will not create additional solid 

waste, but will instead result in a shift 

in how dental amalgam is handled. 

Nationally, EPA expects less dental 

amalgam will partition to the POTW 

wastewater sludge leading to reductions 

in the amount of mercury currently land 

applied, landfilled, or released to the air 

during incineration. Instead, it will be 

collected in separator canisters and 

recycled. Based on this evaluation of 

solid waste generation, EPA concludes 

there will be a reduction in non-water 

quality impacts associated with solid 

waste generation as a result of this 

proposed rule. 

XXI. Implementation and Proposed 

Changes to General Pretreatment 

Regulations in 40 CFR Part 403 

A. Implementation Deadline 

1. Existing Sources 

For existing sources, EPA proposes a 

compliance date of three years after the 

effective date of the final rule. Section 

307(b)(1) of the CWA provides 

categorical pretreatment standards 

‘‘shall specify a time for compliance not 

to exceed three years from the date of 

promulgation.’’ See also 40 CFR 

403.6(b). In proposing a compliance 

date for existing sources subject to this 

proposed rule, EPA considered several 

factors. First, EPA considered the 

burden on Control Authorities (POTWs 

with approved Pretreatment Programs) 

of implementing this rule on an 

industry consisting of approximately 

110,000 dental offices, many of whom 

are small businesses. EPA expects that 

these POTWs will need to develop and 

implement new strategies and programs 

for managing the enforcement and 

compliance of these pretreatment 

standards given that the number of 

possibly affected facilities is 

approximately 10 times the total 

number of dischargers currently 

regulated under any categorical 

pretreatment standard. EPA expects that 

POTWs will need time to conduct 

outreach to dental offices subject to this 

proposed rule. Moreover, EPA envisions 

that dental offices may use the entire 

three year period to come into 

compliance with the numeric standard 

(presumably using amalgam separators) 

and implement the required BMPs. 

2. New Sources 

For new sources, the compliance 

deadline is governed by EPA’s 

regulation at 40 CFR 403.6(b), which 

provides that 

New Sources shall install and have in 

operating condition, and shall ‘start-up’ all 

pollution control equipment required to meet 

applicable Pretreatment Standards before 

beginning to Discharge. Within the shortest 

feasible time (not to exceed 90 days), new 

Sources must meet all applicable 

Pretreatment Standards. 

B. Upset and Bypass Provisions 

A ‘‘bypass’’ is an intentional diversion 

of the streams from any portion of a 

treatment facility. An ‘‘upset’’ is an 

exceptional incident in which there is 

unintentional and temporary 

noncompliance with technology-based 

permit effluent limitations because of 

factors beyond the reasonable control of 

the permittee. EPA’s regulations for 

indirect dischargers concerning 

bypasses and upsets are set forth at 40 

CFR 403.16 and 403.17. 

C. Variances and Modifications 

The CWA requires application of 

pretreatment standards established 

pursuant to sections 304 and 307 for all 

indirect dischargers. However, the 

statute provides for the modification of 

these national requirements in a limited 

number of circumstances. Moreover, the 

Agency has established administrative 

mechanisms to provide an opportunity 

for relief from the application of the 

national pretreatment standards for 

categories of existing sources. 

1. Fundamentally Different Factors 

Variance 

EPA may develop pretreatment 

standards different from the otherwise 

applicable requirements if an individual 

discharger is fundamentally different 

with respect to factors considered in 

establishing the standards applicable to 

the individual discharger. Such a 

modification is known as a 

‘‘fundamentally different factors’’ (FDF) 

variance. See 40 CFR 403.13. EPA, in its 

initial implementation of the effluent 

guidelines and standards program, 

provided for the FDF modifications in 

regulations. These were variances from 

the BCT effluent limitations, BAT 

limitations for toxic and 

nonconventional pollutants, and BPT 

limitations for conventional pollutants 

for direct dischargers. FDF variances for 

toxic pollutants were challenged 

judicially and ultimately sustained by 


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the Supreme Court. (Chemical 

Manufacturers Association v. Natural 

Resources Defense Council, 479 U.S.C. 

116 (1985)). 

Subsequently, in the Water Quality 

Act of 1987, Congress added new CWA 

section 301(n). This provision explicitly 

authorizes modifications of the 

otherwise applicable BAT effluent 

limitations or categorical pretreatment 

standards for existing sources if a 

discharger is fundamentally different 

with respect to the factors specified in 

CWA section 304 or 403 (other than 

costs) from those considered by EPA in 

establishing the effluent limitations or 

pretreatment standards. CWA section 

301(n) also defined the conditions 

under which EPA may establish 

alternative requirements. Under section 

301(n) of the CWA, an application for 

approval of a FDF variance must be 

based solely on (1) information 

submitted during rulemaking raising the 

factors that are fundamentally different 

or (2) information the applicant did not 

have an opportunity to submit. The 

alternate limitation or standard must be 

no less stringent than justified by the 

difference and must not result in 

markedly more adverse non-water 

quality environmental impacts than the 

national limitation or standard. 

EPA regulations at 40 CFR part 403, 

authorizing the Regional Administrators 

to establish alternative standards, 

further detail the substantive criteria 

used to evaluate FDF variance requests 

for existing dischargers to POTWs. 

Thus, 40 CFR 403.13(d) identifies six 

factors (e.g., volume of process 

wastewater, age and size of a 

discharger’s facility) that may be 

considered in determining if a 

discharger is fundamentally different. 

The Agency must determine whether, 

based on one or more of these factors, 

the discharger in question is 

fundamentally different from the 

dischargers and factors considered by 

EPA in developing the nationally 

applicable pretreatment standards. The 

regulation also lists four other factors 

(e.g., inability to install equipment 

within the time allowed or a 

discharger’s ability to pay) that may not 

provide a basis for an FDF variance. In 

addition, under 40 CFR 403.13(c)(2), a 

request for standards less stringent than 

the national standard may be approved 

only if compliance with the 

pretreatment standards would result in 

either (a) a removal cost wholly out of 

proportion to the removal cost 

considered during development of the 

pretreatment standards, or (b) a nonwater quality environmental impact 

(including energy requirements) 

fundamentally more adverse than the 

impact considered during development 

of the pretreatment standards. The 

legislative history of section 301(n) of 

the CWA underscores the necessity for 

the FDF variance applicant to establish 

eligibility for the variance. EPA’s 

regulations at 40 CFR 403.13 are explicit 

in imposing this burden upon the 

applicant. The applicant must show that 

the factors relating to the discharge 

controlled by the applicant’s permit 

which are claimed to be fundamentally 

different are, in fact, fundamentally 

different from those factors considered 

by EPA in establishing the applicable 

pretreatment standards. In practice, very 

few FDF variances have been granted for 

past ELGs. An FDF variance is not 

available to a new source subject to 

PSNS. 

2. Economic Variances 

Section 301(c) of the CWA authorizes 

a variance from the otherwise applicable 

PSES and PSNS for nonconventional 

pollutants due to economic factors. As 

this rule controls toxic pollutants and 

only controls nonconventional 

pollutants that are also found in the 

same waste stream, this variance would 

not be applicable to this particular rule. 

D. What are the roles of key entities 

involved in implementing the rule and 

how are pretreatment standards 

implemented? 

EPA recognizes the role of many 

interested parties in the development of, 

and, ultimately, the successful 

implementation of pretreatment 

standards for dental dischargers. To the 

greatest extent possible, EPA has 

attempted to strike a reasonable balance 

among the many interests. A short 

summary of the various roles involved 

in implementing categorical 

pretreatment standards is provided 

below. 

1. Control Authorities 

The ‘‘Control Authority’’ refers to the 

POTW if the POTW has an approved 

Pretreatment Program, or the Approval 

Authority if it has not been approved, 

which may be the state or EPA. A 

POTW is a treatment works as defined 

by section 212(2) of the CWA, which is 

owned by a state or municipality (as 

defined in CWA sections 502 (3) and (4), 

respectively). (see 40 CFR 403.3(q).) 

POTWs collect wastewater from homes, 

commercial buildings, and industrial 

facilities and typically transport it via a 

series of pipes, known as a collection 

system, to the treatment plant. Most 

POTWs are not designed to treat the 

toxics in commercial and industrial 

wastes, which can cause pass through, 

interfere with, or are otherwise 

incompatible with the operation of 

POTWs, including sludge disposal 

methods at POTWs. The General 

Pretreatment Regulations require 

POTWs that meet certain criteria (e.g. 

minimum design flow) to develop 

Pretreatment Programs to control 

industrial Discharges into their sewage 

collection systems, unless the state 

exercises its option to assume local 

responsibilities as provided in EPA’s 

regulations at 40 CFR 403.10(e) and (f). 

Today there are an estimated 1500 

approved POTW Pretreatment Programs. 

As required under 40 CFR part 403, 

Control Authorities implement and 

enforce control mechanisms (e.g., 

permits) to the Industrial Users (IUs) 

that discharge to their systems, inspect 

and sample, and enforce control 

requirements in order to protect the 

POTW against discharges which ‘‘pass 

through’’ or cause interference’’ with the 

POTW (see 40 CFR 403.3(p) and (k)). 

2. Approval Authority 

The Director in an NPDES state with 

an approved state Pretreatment Program 

may be authorized to serve as the 

Approval Authority for the 

implementation of a general 

pretreatment program. (40 CFR 

403.3(c)). Thirty-six states have such 

approved Pretreatment Programs and 

are authorized to serve as Approval 

Authorities for implementation of the 

Pretreatment Program. In a non-NPDES 

state or an NPDES state without an 

approved state Pretreatment Program, 

the EPA Regional Administrator is the 

Approval Authority. 

3. EPA 

EPA establishes and implements 

national regulations for Pretreatment 

Programs and categorical pretreatment 

standards for certain industries such as 

the pretreatment standards for dental 

amalgam proposed today. EPA also 

develops policy and guidance and 

provides training and oversight for 

Pretreatment Program implementation. 

As noted above, EPA’s Regional 

Administrator serves as the Approval 

Authority for a non-NPDES state or an 

NPDES state without an approved state 

Pretreatment Program, and as the 

Control Authority for POTWs without 

an approved Pretreatment Program in 

these states. 

4. Industrial Dischargers (i.e. Dentists) 

IUs of POTWs must comply with 

Pretreatment Standards prior to 

introducing pollutants into a POTW. 

The General Pretreatment Regulations 

include general prohibitions that forbid 

IUs from causing pass through and 

interference (i.e., cause the POTW to 


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violate its permits limits, or interfere 

with the operation of the POTW or the 

beneficial use of its sewage sludge), and 

specific prohibitions against the 

discharge of pollutants that cause 

problems at the POTW such as 

corrosion, fire or explosion, and danger 

to worker health and safety. As 

discussed in this document, EPA may 

also develop national categorical 

pretreatment standards, including 

numeric pollutant limits and BMPs, for 

IUs in specific industrial categories. The 

General Pretreatment Regulations 

include reporting and other 

requirements necessary to implement 

these categorical standards (e.g., 40 CFR 

403.12). 

E. What are the Control Authority 

requirements under existing General 

Pretreatment Regulations? 

The current regulations require 

certain minimum oversight of IUs by 

Control Authorities, which are typically 

POTWs with Approved Pretreatment 

Programs but could be states or EPA 

acting as Pretreatment Control 

Authorities. The required minimum 

oversight includes receipt and analysis 

of reports and other notices submitted 

by IUs, randomly sampling and 

analyzing effluent from IUs, and 

conducting surveillance activities to 

identify occasional and continuing noncompliance with pretreatment 

standards. In addition, for IUs 

designated as significant industrial 

users (SIUs), per 40 CFR 403.3(v), 

Control Authorities must inspect and 

sample the SIU effluent annually, 

review the need for a slug control plan, 

and issue a Permit or equivalent control 

mechanism with a duration not to 

exceed five years (40 CFR 403.8(f)(1)(iii) 

and 403.8(f)(2)(v), 403.10(e) and 

403.10(f)(2)(i)). Control authorities may 

determine that an industrial user is a 

non-significant categorical industrial 

user or that an industrial user is not an 

SIU (see 40 CFR 403.3(v)(2) and (v)(3)). 

Facilities that are subject to 

categorical pretreatment standards 

contained in regulations in 40 CFR 

Chapter I, subchapter N are referred to 

as Categorical Industrial Users (CIUs). 

The regulations related to SIU at 40 CFR 

403.3(v) define SIU to include CIUs, but 

also provide that a Control Authority 

may determine that a CIU may be a NonSignificant Categorical Industrial User 

(NSCIU) if certain conditions are met. 

(see 403.3(v)(1) and (v)(2)). State 

Approval Authorities and POTW 

Control Authorities who have the legal 

authority to implement the NSCIU 

classification may find some of their 

CIUs satisfy the qualifying conditions of 

NSCIU at 40 CFR 403.3(v)(2). Upon such 

finding, the Control Authority may 

exclude facilities meeting the NSCIU 

criteria from the SIU definition and its 

minimum oversight requirements. A 

Control Authority may not exclude CIUs 

from the requirements of the categorical 

pretreatment standards. 

F. Why is EPA revising the existing 

General Pretreatment Regulations? 

EPA proposes to amend selected parts 

of the General Pretreatment Regulations 

in order to simplify oversight 

requirements for the approximately 

110,000 dental offices subject to this 

proposed rule. As mentioned in 

paragraph E. of this section, when EPA 

promulgates categorical industrial 

pretreatment standards, as defined in 40 

CFR part 403, affected dischargers are 

referred to as Categorical Industrial 

Users (CIUs). The number of dental 

offices that would be subject to this 

proposed rule is approximately ten 

times the current number of Categorical 

Industrial Users. EPA recognizes 

regulatory oversight of this increased 

number of CIUs would need to be very 

different from regulating the current 

number of CIUs. Using the existing 

regulatory framework, enforcement of 

categorical pretreatment regulation on 

this industry would require an increase 

in local, state and federal resources 

whereas EPA does not expect such 

efforts to result in greater environmental 

benefit. EPA is focused on providing 

technical means to reduce 

administrative burden to dentists and 

Control Authorities, while still 

providing a clear understanding of who 

is affected and what they are expected 

to do, as well as achieving the projected 

pollutant reductions. EPA estimates that 

these changes to the Existing General 

Pretreatment Standards would reduce 

costs to POTWs to implement and 

enforce this proposed rule by $47 

million annually (see TEDD). 

G. What changes is EPA proposing to 

the General Pretreatment Standards? 

EPA proposes a new classification of 

CIU specifically tailored to the Dental 

Office Effluent Limitations Guidelines 

and Standards rule, ‘‘Dental Industrial 

User’’ (DIU). EPA proposes that such 

Users not be subject to the oversight 

requirements for SIUs (i.e., control 

mechanism issuance requirement, 

annual inspection and sampling 

requirements). Rather, EPA proposes to 

allow Control Authorities to focus their 

oversight efforts on those dental office 

facilities that fail to meet the 

compliance requirements of the DIU. 

H. When is a dental office a DIU? 

Under the proposed rule, a dental 

discharger is given the option of 

complying with monitoring and 

reporting requirements in 40 CFR 

441.60, which are tailored for dental 

dischargers, in lieu of the otherwise 

applicable monitoring and reporting 

requirements in 40 CFR part 403. If a 

dental discharger complies with (1) the 

special monitoring and reporting 

requirements in 40 CFR 441.60, (2) the 

remaining 40 CFR part 403 

requirements, and the applicable 

pretreatment standards (PSES or PSNS), 

then the Control Authority may treat the 

dental discharger as a DIU. The DIU 

must maintain compliance in order to 

retain its DIU status. 

I. When is a dental office not a DIU? 

If the dental office does not meet the 

requirements to be treated as a DIU, 

under this proposal the Control 

Authority must treat the dental 

discharger as a Significant Industrial 

User as defined in 40 CFR 403.3(v). As 

a Significant Industrial User, the POTW 

Control Authority would be required to 

conduct the oversight duties applicable 

to SIUs as described in 40 CFR 403.8(f). 

J. What oversight responsibilities for 

DIUs is EPA proposing for Control 

Authorities? 

This proposal would require that a 

Control Authority evaluate, at least once 

per year, whether an IU previously 

determined to be a DIU still meets the 

criteria for treatment as a DIU under 40 

CFR 441.60. EPA anticipates that this 

evaluation will primarily involve the 

Control Authority’s verification that the 

certification has been submitted by the 

dental office documenting continued 

eligibility for DIU status. In accordance 

with 40 CFR 403.8(f)(2)(viii)(F), a dental 

discharger would be in significant 

noncompliance if it fails to provide any 

required report within 45 days of the 

due date or if the Control Authority 

elects to inspect the facility and finds 

the facility is not in compliance with 40 

CFR 441.60. Upon discovery that a 

dental office is not in compliance with 

regulations at 40 CFR 441.60 (either 

reporting requirements, 403, or 441 

PSES/PSNS requirements), the Control 

Authority must initiate enforcement in 

accordance with its approved 

Pretreatment Program to return the 

dental discharger into compliance. In 

order for the Control Authority to 

continue to treat the dentist as a DIU, 

the Control Authority would need to 

verify and find, through an inspection, 

that the dental discharger has returned 

to full compliance with the criteria in 40 


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CFR 441.60. If, within 90 days, the 

Control Authority inspects, verifies, and 

finds that the dental discharger has 

returned to full compliance with 40 CFR 

441.60, then the dental discharger 

would remain a DIU. The 90 day 

compliance deadline is consistent with 

other portions of 40 CFR part 403 (e.g., 

significant noncompliance compliance 

report deadlines, 90 day report after 

effective dates of categorical standards), 

and provides both the dental discharger 

and Control Authority with an incentive 

to provide a timely return to 

compliance. If the dental discharger has 

not returned to compliance within 90 

days of the initial noncompliance, the 

Control Authority could no longer treat 

the dental discharger as a DIU and the 

dental discharger would become a 

Significant Industrial User. Control 

Authorities are required to provide 

oversight of SIUs which includes 

inspection and sampling of each SIU 

annually, reviewing the need for a slug 

control plan, and issuing a Permit or 

equivalent control mechanism with a 

duration not to exceed five years (40 

CFR 403.8(f)(1)(iii) and (f)(2)(v) and 

403.10(f)(2)(i)). 

K. Can a dental office DIU be a NonSignificant Industrial User (NSCIU)? 

EPA does not propose to prohibit a 

Control Authority from finding that a 

dental office may qualify as an NSCIU 

on an individual basis. State Approval 

Authorities and POTW Control 

Authorities who have the legal authority 

to implement the NSCIU classification 

may find that one or more of their 

dental office CIUs may qualify as 

NSCIUs. However, since its 

promulgation in 2005, many state 

Approval Authorities and POTW 

Control Authorities have not adopted 

regulations to implement the NSCIU 

classification. EPA believes that the DIU 

classification, tailored for this single 

categorical pretreatment standard, while 

comparable to the NSCIU classification, 

would be preferable, because it would 

significantly reduce the Control 

Authority’s burden in complying with 

the oversight requirements that would 

otherwise apply. 

L. Can Dental Industrial Users be 

covered under a general permit? 

Although this proposed rule does not 

require a Control Authority to regulate 

DIUs as SIUs thereby requiring the 

Control Authority to issue a control 

mechanism, designation of a dental 

office subject to 40 CFR part 441 as a 

DIU does not preclude a Control 

Authority’s option to regulate the dental 

office under a general control 

mechanism, 40 CFR 403.8(f)(1)(iii)(A), if 

that legal authority is adopted. The 

General Pretreatment Regulations 

describe conditions which must be met 

in order for the Control Authority to use 

a general control mechanism in lieu of 

an individual permit or control 

mechanism. Provided that the Control 

Authority adopted the necessary legal 

authority and modified its Pretreatment 

Program to incorporate such authority 

and procedures, the Control Authority 

may use a general control mechanism or 

‘‘general permit’’ for facilities that meet 

certain minimum criteria for being 

considered substantially similar. The 

use of general control mechanisms 

allows the permitting authority to 

allocate resources in a more efficient 

manner and to provide timelier permit 

coverage, particularly in the 

circumstances of covering large 

numbers of similar facilities under a 

single mechanism. EPA considers that 

most dental offices generally will 

conform to these requirements and 

could appropriately be covered by a 

general control mechanism issued by a 

Control Authority. The use of a general 

control mechanism also ensures 

consistency of permit conditions for 

similar facilities. Additional 

information on the use of general 

control mechanisms may be found in 

the Federal Register of October 14, 2005 

(70 FR 60143). 

M. Would any POTW with a dentist 

office in its service area be required to 

develop a Pretreatment Program? 

In accordance with 40 CFR 403.8(a), 

POTWs (or combination of POTWs 

operated by the same authority) with a 

total design flow greater than 5 million 

gallons per day and receiving pollutants 

from IUs which pass through or 

interfere with the operation of the 

POTW or are otherwise subject to 

Pretreatment Standards are required to 

establish a POTW Pretreatment Program 

unless the state with an approved 

Pretreatment Program exercises its 

option to assume local responsibilities 

as provided for in 40 CFR 403.10(e). For 

smaller POTWs, POTWs that have a 

design flow of 5 million gallons per day 

or less, the Regional Administrator or 

state Director may require the POTW to 

develop a local Pretreatment Program if 

the nature or volume of the industrial 

influent, treatment process upsets, 

violations of POTW effluent limitations, 

contamination of municipal sludge, or 

other circumstances warrant such 

development in order to prevent 

interference or pass through. 

Interference and pass through are 

defined at 40 CFR 403.3(k) and (p), 

respectively. As noted above, a state 

with an Approved state Pretreatment 

Program may instead assume local 

responsibilities as provided in 40 CFR 

403.10(e). EPA anticipates that the 

approved states will choose to carry out 

the oversight activities themselves 

rather than requiring a POTW to 

develop a full Pretreatment Program 

solely to regulate its dental dischargers. 

N. Would states or municipalities that 

already implement Dental Amalgam 

Control Programs need to modify their 

regulations? 

The proposed rulemaking would not 

affect existing state and local 

requirements that control discharges of 

dental amalgam. However, states with 

approved state programs and POTWs 

with approved Pretreatment Programs 

would need to enforce the federal 

requirements at a minimum. The new 

federal requirements include removal of 

at least 99.0% of total mercury from 

amalgam discharges which can be 

accomplished through proper use of a 

2008 ISO 11143 certified amalgam 

separator with a removal efficiency of at 

least 99.0%. The proposal at part 

441.40(d) would allow dentists 

currently operating amalgam separators 

no less efficient than 95% to continue 

to operate their separators for ten years 

before they would be required to meet 

the 99% removal standard. Where 

ongoing state or POTW Control 

Authority programs require additional 

information or implementation 

requirements, the Control Authority 

must implement and enforce both 

program requirements and, for 

overlapping requirements, the more 

stringent of the two programmatic 

requirements. 

O. Will states or municipalities that 

already implement Dental Amalgam 

Control Programs need to issue control 

mechanisms or permits to impose 

requirements that are more stringent 

than the federal requirements? 

The legal authority requirements for a 

POTW Pretreatment program only 

require issuance of an individual or 

general control mechanism to SIUs, 40 

CFR 403.8(f)(2)(1)(iii)(A). The proposed 

regulation modification in the General 

Pretreatment Regulations is to establish 

a new DIU classification of Industrial 

User. The proposal indicates that a DIU 

will not be a Significant Industrial User. 

Where the state or POTW existing 

dental amalgam control programs are 

equal to or less stringent than this 

proposal, and the state or Control 

Authority adopt and have their 

Pretreatment Programs appropriately 

approved to incorporate EPA’s DIU 

provisions, dental offices compliant 


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28Today’s proposal does not apply to third-party 

vendors because they are not dental dischargers, 

and therefore, as such, EPA cannot compel a thirdparty vendor to meet any reporting requirements. 

29This estimate reflects approximately three 

hours per office in the first year and one hour each 

subsequent year. 

with the DIU classification will not need 

to be issued a control mechanism. 

P. What reports would dental 

dischargers be required to submit? 

Existing and new dental dischargers 

could comply with the special reporting 

requirements in 40 CFR part 441 in lieu 

of the otherwise applicable reporting 

requirements in 40 CFR part 403 by 

submitting the Baseline Report (40 CFR 

441.60(a)(1)) and the 90 Day 

Compliance Report (40 CFR 

441.60(a)(2)) and Periodic Monitoring 

reports (40 CFR 441.60(a)(3)). 

Submission of these reports would 

satisfy the reporting requirements in 40 

CFR parts 403 and 441. Dental 

dischargers who do not submit reports 

consistent with the requirements in 40 

CFR 441.60 would be required to submit 

the reports described in 40 CFR 

403.12(b), (d), and (e). 

Q. Can the DIU designate a contractor 

or contract vendor to submit 

Compliance Reports to the Control 

Authority or EPA? 

In accordance with 40 CFR 403.12(l), 

Baseline Monitoring Reports, 90-day 

Compliance Reports, and Periodic 

monitoring reports (40 CFR 403.12(b), 

(d), and (e), respectively) must be signed 

by (1) a responsible corporate officer of 

the IU if it is a corporation; (2) a general 

partner or proprietor if the IU is a 

partnership or sole proprietorship; or (3) 

a duly authorized representative of the 

responsible corporate officer, general 

partner, or proprietor if the 

authorization specifies either an 

individual or a position having 

responsibility for the overall operation 

of the facility from which the industrial 

discharge originates, such as the 

position of plant manager or a position 

of equivalent responsibility for 

environmental matters for the company 

and the written authorization is 

submitted to the Control Authority.28

This does not preclude a third-party 

from submitting the reports as long as 

the submission includes the proper 

signature from the DIU. 

R. Would Control Authorities need to 

modify their Sewer Use Ordinance and 

state regulations, respectively, to 

incorporate these changes to 40 CFR 

part 403? 

The proposed changes to 40 CFR part 

403 to create the DIU classification are 

changes that the Control Authority may 

adopt at its discretion. The changes to 

40 CFR part 403 provide program 

flexibility and are not required to be 

incorporated into the state or POTW’s 

Pretreatment Program. However, for 

Control Authorities to designate dental 

offices as DIUs, the state and POTW 

Pretreatment program would need to 

incorporate these changes into their 

legal authority under 40 CFR 403.8(f)(l). 

XXII. Statutory and Executive Order 

Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

Under Executive Order 12866 (58 FR 

51735, October 4, 1993), this action is a 

‘‘significant regulatory action.’’ 

Accordingly, EPA submitted this action 

to the OMB for review under Executive 

Orders 12866 and 13563 (76 FR 3821, 

January 21, 2011) and any changes made 

in response to OMB recommendations 

have been documented in the docket for 

this action. 

B. Paperwork Reduction Act 

The information collection 

requirements in this proposed rule have 

been submitted for approval to the OMB 

under the Paperwork Reduction Act, 44 

U.S.C. 3501 et seq. The Information 

Collection Request (ICR) document 

prepared by EPA has been assigned EPA 

ICR number 2514.01. To reduce the 

overall costs associated with this rule, 

in lieu of discharge monitoring, 

proposed 40 CFR 441.60 allows dentists 

to certify compliance with requirements 

for amalgam capture and certain BMPs. 

For purposes of this estimate, EPA 

assumed all affected dentists would 

elect to comply with this proposal 

through certification rather than 

discharge monitoring. EPA estimates it 

would take a total annual average of 

153,000 hours 29 and $2.5 million for 

affected dental offices to collect and 

report the information required for 

certification in the proposed rule. This 

estimate includes effort for each dental 

office associated with completing the 

baseline monitoring report, a one-time 

compliance report and an annual 

compliance certification for each year of 

a three year ICR. This estimate is based 

on average labor rates from the Bureau 

of Labor Statistics for the dental office 

personnel involved in collecting and 

reporting the information required. EPA 

estimates it would take a total annual 

average of 17,400 hours and $960,000 

for control authorities to review the 

information submitted by dentists that 

certify they meet the requirements in 

the proposed rule. EPA estimates that 

there would be no start-up or capital 

costs associated with the information 

described above. Burden is defined at 5 

CFR 1320(b). 

An agency may not conduct or 

sponsor, and a person is not required to 

respond to, a collection of information 

unless it displays a currently valid OMB 

control number. The OMB control 

numbers for EPA’s regulations in 40 

CFR are listed in 40 CFR part 9. 

To comment on the Agency’s need for 

this information, the accuracy of the 

provided burden estimates, and any 

suggested methods for minimizing 

respondent burden, EPA has established 

a public docket for this proposed rule, 

which includes this ICR, under Docket 

identification ID number EPA–HQ–OW– 

2014–0693. Submit any comments 

related to the ICR to EPA and OMB. See 

ADDRESSES section in this document for 

where to submit comments to EPA. 

Since OMB is required to make a 

decision concerning the ICR between 30 

and 60 days after October 22, 2014, a 

comment to OMB is best assured of 

having its full effect if OMB receives it 

by November 21, 2014. The final rule 

will respond to any OMB or public 

comments on the information collection 

requirements contained in this proposal. 

C. Regulatory Flexibility Act 

The Regulatory Flexibility Act (RFA) 

generally requires an agency to prepare 

a regulatory flexibility analysis of any 

rule subject to notice and comment 

rulemaking requirements under the 

Administrative Procedure Act or any 

other statute unless the agency certifies 

that the rule will not have a significant 

economic impact on a substantial 

number of small entities. Small entities 

include small businesses, small 

organizations, and small governmental 

jurisdictions. 

For purposes of assessing the impacts 

of this proposed rule on small entities, 

small entity is defined as: (1) A small 

business in the Dental Office sector 

(NAICS 621210) with annual receipts of 

7 million dollars or less (based on SBA 

size standards); (2) a small 

governmental jurisdiction that is a 

government of a city, county, town, 

school district or special district with a 

population of less than 50,000; and (3) 

a small organization that is any not-forprofit enterprise which is independently 

owned and operated and is not 

dominant in its field. 

EPA estimates that 109,600 dental 

offices out of 109,859 dental offices 

potentially subject to this proposal meet 

the small business definition. EPA’s 

analysis of projected impacts on small 

dental offices is described in detail in 


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Section XVI. EPA projects less than 1% 

of 109,859 affected dental offices would 

incur compliance costs exceeding 1% of 

revenue and no more than 0.2% would 

incur compliance costs exceeding 3% of 

revenue. After considering the economic 

impact of this proposed rule on small 

entities, I certify that this action will not 

have a significant economic impact on 

a substantial number of small entities. 

Although this proposed rule will not 

have a significant economic impact on 

a substantial number of small entities, 

EPA nonetheless has tried to reduce the 

impact of this proposed rule on small 

entities. First, while some amalgam 

separators currently used at some 

dentists are certified to meet slightly 

less mercury removal than required in 

this proposed rule (e.g., they are 

certified to remove 95% total mercury), 

this proposal would allow dentists with 

existing separators to satisfy the 

requirements for a period of up to 10 

years. See Section XIV. In addition, this 

proposed rule includes a compliance 

option that would allow dental offices 

subject to the rule to certify proper 

operation of a widely available, 

inexpensive technology that meets 

certain requirements in combination 

with BMPs in lieu of conducting more 

onerous discharge monitoring 

requirements that would otherwise be 

associated with pretreatment standards. 

Finally, EPA has tried to minimize 

impacts to small governments 

responsible for Pretreatment Programs 

by proposing to amend the General 

Pretreatment Regulations to create the 

DIU classification. The DIU 

classification reduces oversight 

responsibilities for Control Authorities 

from the current regulatory scheme, 

while at the same time achieving the 

projected pollutant reductions. We 

continue to be interested in the 

potential impacts of the proposed rule 

on small entities and welcome 

comments on issues related to such 

impacts. 

D. Unfunded Mandates Reform Act 

(UMRA) 

This proposed rule does not contain 

a Federal mandate that may result in 

expenditures of $100 million or more 

for state, local, and tribal governments, 

in the aggregate, or the private sector in 

any 1 year. As explained in Section XVI, 

the annual cost of the proposed rule is 

$44–$49 million. Thus, this proposed 

rule is not subject to the requirements 

of sections 202 or 205 of UMRA. 

The proposal is also not subject to the 

requirements of section 203 of UMRA, 

because it contains no regulatory 

requirements that may significantly or 

uniquely affect small governments. EPA 

has not identified any dental offices that 

are owned by small governments. While 

this proposal would impact government 

entities required to administer the 

proposed pretreatment standards, EPA 

does not expect that this would include 

any small governments. By statute, a 

small government jurisdiction is defined 

as a government of a city, county, town, 

school district or special district with a 

population of less than 50,000 (5 U.S.C. 

601). As explained in Section XXI, 

control authorities are responsible for 

oversight and administration associated 

with this proposal. To qualify as a 

Control Authority, a POTW must have 

a flow of at least 5 million gallons per 

day. The average water use per person 

is 100 gallons per day so a POTW with 

a population less than 50,000 would 

likely have a flow less than 5 MGD. 

Therefore, EPA does not expect small 

government owned POTWs would meet 

the definition of a Control Authority. 

E. Executive Order 13132: Federalism 

This proposed rule would not have 

federalism implications. It would not 

have substantial direct effects on the 

states, on the relationship between the 

national government and the states, or 

on the distribution of power and 

responsibilities among the various 

levels of government, as specified in 

Executive Order 13132. The proposed 

rule would not alter the basic statefederal scheme established in the CWA 

under which EPA authorizes states to 

carry out the NPDES permit program. 

EPA expects the proposed rule would 

have little effect on the relationship 

between, or the distribution of power 

and responsibilities among, the federal 

and state governments. Thus, Executive 

Order 13132 does not apply to this 

proposed rule. 

EPA coordinated closely with states, 

via ECOS and local governments and 

with NACWA, throughout the 

development of this proposed rule. In 

the spirit of Executive Order 13132, and 

consistent with EPA policy to promote 

communications between EPA and state 

and local governments, EPA specifically 

solicits comment on this proposed rule 

from state and local officials. 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

This proposed rule does not have 

tribal implications, as specified in 

Executive Order 13175 (65 FR 67249, 

November 6, 2000). It would not have 

substantial direct effects on Tribal 

governments, on the relationship 

between the Federal government and 

Indian Tribes, or on the distribution of 

power and responsibilities between the 

Federal government and Indian Tribes. 

This proposed rule contains no Federal 

mandates for Tribal governments and 

does not impose any enforceable duties 

on Tribal governments. Thus, Executive 

Order 13175 does not apply to this rule. 

EPA specifically solicits additional 

comment on this proposed action from 

Tribal officials. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

and Safety Risks 

Executive Order 13045 (62 FR 19885, 

April 23, 1997) applies to rules that are 

economically significant according to 

Executive Order 12866 and involve a 

health or safety risk that may 

disproportionately affect children. This 

action is not subject to Executive Order 

13045 because it is estimated to cost less 

than $100 million and does not involve 

a safety or health risk that may have 

disproportionately negative effects on 

children. The proposed rule will reduce 

the amount of mercury from dental 

amalgam entering POTW’s and 

eventually the nation’s waters, which 

will reduce impacts to the neurological 

development of children. 

H. Executive Order 13211: Energy 

Effects 

This proposed rule is not a 

‘‘significant energy action’’ as defined in 

Executive Order 13211, ‘‘Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use’’ (66 FR 28355, May 

22, 2001) because it is not likely to have 

a significant adverse effect on the 

supply, distribution, or use of energy, as 

described in Section XX of this 

proposal. EPA determined that any 

additional energy usage would be 

insignificant to the total energy usage of 

Dental Offices and total annual U.S. 

energy consumption. 

I. National Technology Transfer 

Advancement Act 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act (NTTAA) of 1995, (Pub. L. 104–113; 

15 U.S.C. 272 note) directs EPA to use 

voluntary consensus standards in its 

regulatory activities unless to do so 

would be inconsistent with applicable 

law or otherwise impractical. Voluntary 

consensus standards are technical 

standards (e.g., materials specifications, 

test methods, sampling procedures, and 

business practices) that are developed or 

adopted by voluntary consensus 

standard bodies. The NTTAA directs 

EPA to provide Congress, through OMB, 

explanations when the Agency decides 

not to use available and applicable 

voluntary consensus standards. 


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63284 Federal Register / Vol. 79, No. 204 / Wednesday, October 22, 2014 / Proposed Rules 

This proposed rulemaking involves 

technical standards. The International 

Organization for Standardization (ISO) 

developed efficiency standards for 

amalgam separators (ISO 11143) in 1999 

and updated these standards in 2008. 

EPA proposes to use ISO 11143 2008. 

This voluntary standard setting 

organization established a standard for 

measuring amalgam separator efficiency 

by evaluating the retention of amalgam 

mercury using specified test procedures 

in a laboratory setting. It also includes 

requirements for instructions for use 

and operation and maintenance. 

EPA welcomes comments on this 

aspect of the proposed rulemaking and, 

specifically, invites the public to 

identify potentially-applicable 

voluntary consensus standards and to 

explain why such standards should be 

used in this regulation. 

J. Executive Order 12898: Federal 

Actions To Address Environmental 

Justice in Minority Populations and 

Low-Income Populations 

Executive Order 12898 (59 FR 7629, 

Feb. 16, 1994) establishes federal 

executive policy on environmental 

justice. Its main provision directs 

federal agencies, to the greatest extent 

practicable and permitted by law, to 

make environmental justice part of their 

mission by identifying and addressing, 

as appropriate, disproportionately high 

and adverse human health or 

environmental effects of their programs, 

policies, and activities on minority 

populations and low-income 

populations in the United States. 

EPA has determined that this 

proposed rule will not have 

disproportionately high and adverse 

human health or environmental effects 

on minority or low-income populations. 

While EPA was unable to perform a 

detailed environmental justice analysis 

because it lacks data on the location of 

POTWs to which dental discharges 

currently occur, the proposal would 

increase the level of environmental 

protection for all affected populations 

without having any disproportionately 

high and adverse human health or 

environmental effects on any 

population, including any minority or 

low-income population. The proposed 

rule will reduce the amount of mercury 

from dental amalgam entering POTW’s 

and eventually the nation’s waters, to 

benefit all of society, including minority 

communities. 

EPA welcomes comments on this 

aspect of the proposed rulemaking and, 

specifically, invites the public to 

identify potential environmental justice 

considerations associated with this 

proposed regulation. 

List of Subjects in 40 CFR Parts 403 and 

441 

Environmental protection, Dental, 

Dental office, Dentist, Mercury, 

Pretreatment, Waste treatment and 

disposal, Water pollution control. 

Dated: September 23, 2014. 

Gina McCarthy, 

Administrator. 

Therefore, it is proposed that 40 CFR 

parts 403 and 441 be amended as 

follows: 

PART 403—GENERAL 

PRETREATMENT REGULATIONS FOR 

EXISTING AND NEW SOURCES OF 

POLLUTION 

■ 1. The authority citation for part 403 

continues to read as follows: 

Authority: 33 U.S.C. 1251, 1311, 1314, 

1316, 1317, 1318, 1342, and 1361. 

■ 2. In § 403.3, add paragraph (v)(4) to 

read as follows: 

§ 403.3 Definitions. 

* * * * * 

(v) * * * 

(4) An industrial user subject to 

categorical Pretreatment Standards 

under 40 CFR part 441 is designated a 

Dental Industrial User (DIU) rather than 

a Significant Industrial User (SIU) if the 

Industrial User (IU) has complied with 

40 CFR part 403, the applicable 

pretreatment standards for existing 

sources (PSES) or pretreatment 

standards for new sources (PSNS) and 

the monitoring and reporting 

requirements of 40 CFR 441.60. If a DIU 

has not complied with these 

requirements and standards, such IU 

will be considered a SIU until the 

Control Authority evaluates the IU as 

specified in § 403.8(f)(2)(v)(D). 

* * * * * 

■ 3. In § 403.8, add paragraph 

(f)(2)(v)(D) to read as follows: 

§ 403.8 Pretreatment Program 

Requirements: Development and 

Implementation by POTW. 

* * * * * 

(f) * * * 

(2) * * * 

(v) * * * 

(D) Where the publicly owned 

treatment works (POTW) finds that an 

Industrial User (IU) meets the criteria 

for classification as a Dental Industrial 

User (DIU), the POTW must evaluate, at 

least once per year, whether the IU 

meets the criteria in § 403.3(v)(4). In the 

event that the POTW determines that a 

DIU does not meet the criteria in 

§ 403.3(v)(4), the POTW must 

immediately begin enforcement in 

accordance with its enforcement 

response plan. If the dental discharger 

has not returned to compliance within 

90 days of the initial noncompliance, 

the POTW may no longer treat the 

dental discharger as a DIU and must 

treat the dental discharger as a SIU. 

Upon verification by the POTW through 

an inspection and a finding that the 

dental discharger has complied with all 

of the applicable requirements in 

§ 403.3(v)(4), the dental discharger may 

be considered a DIU. 

* * * * * 

■ 4. Add part 441 to read as follows: 

PART 441—DENTAL OFFICE 

(MERCURY AMALGAM) POINT 

SOURCE CATEGORY 

Sec. 

441.10 Applicability. 

441.20 General definitions. 

441.30 General pretreatment requirements. 

441.40 Pretreatment standards for existing 

sources (PSES). 

441.50 Pretreatment standards for new 

sources (PSNS). 

441.60 Discharge monitoring, reporting, and 

recordkeeping requirements. 

Authority: 33 U.S.C. 1251, 1311, 1314, 

1316, 1317, 1318, 1342, and 1361. 42 U.S.C. 

13101 et seq. 

§ 441.10 Applicability. 

(a) Except as provided in paragraphs 

(b) and (c) of this section, the provisions 

of this part are applicable to discharges 

of wastewater to publicly owned 

treatment works from facilities where 

the practice of dentistry is performed 

(‘‘dental dischargers’’), including but 

not limited to institutions, permanent or 

temporary offices, clinics, mobile units, 

home offices, and facilities, and 

including dental facilities owned and 

operated by Federal, state, or local 

governments. 

(b) The provisions of this part do not 

apply to process wastewater discharges 

from dental dischargers which 

exclusively practice one or more of the 

following dental specialties: oral 

pathology, oral and maxillofacial 

radiology, oral and maxillofacial 

surgery, orthodontics, periodontics, or 

prosthodontics; 

(c) Dental Dischargers will be exempt 

from any further requirements of this 

rule so long as they: 

(1) Do not place or remove amalgam 

except in limited emergency 

circumstances 

(2) Certify to the Control Authority 

that that they do not and will not use 

or remove amalgam, including the 

following information: 

(i) The facility name, address, contact 

information. 

(ii) The dental license number of all 

practicing dentists at the location. 


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(3) Notify the Control Authority of 

any changes to information required 

under paragraphs (c)(2)(i) and (ii) of this 

section. 

(4) Information provided to comply 

with paragraphs (c)(2)(i) and (ii) of this 

section must be signed by the 

responsible corporate officer as defined 

in § 403.12(l). 

§ 441.20 General definitions. 

For purposes of this part: 

Amalgam process wastewater means 

any wastewater generated and 

discharged by a dental discharger 

through the practice of dentistry that 

may contain dental amalgam. 

Amalgam separator means a 

collection device designed to capture 

and remove dental amalgam from the 

amalgam process wastewater of a dental 

facility. 

Control Authority is defined in 40 

CFR 403.3(f). 

Dental amalgam means an alloy of 

elemental mercury and other metals that 

is used in the practice of dentistry. 

Dental Discharger means a source of 

wastewater to a publicly owned 

treatment works from a facility where 

the practice of dentistry is performed as 

described in 40 CFR 441.10. 

Dental Industrial User (DIU) means a 

dental discharger as described in 

§ 441.10(a) that meets the requirements 

of 40 CFR 441.60. 

§ 441.30 General pretreatment 

requirements. 

(a) Any source subject to this part that 

introduces process wastewater 

pollutants into a publicly owned 

treatment works (POTW) must comply 

with 40 CFR part 403. 

(b) [Reserved] 

§ 441.40 Pretreatment standards for 

existing sources (PSES). 

Except as provided in 40 CFR 403.7 

(removal credits) and 403.13 

(fundamentally different factors) and no 

later than [DATE 3 YEARS AFTER 

EFFECTIVE DATE OF THE FINAL 

RULE IN THE FEDERAL REGISTER], 

any existing source subject to this part 

must achieve the following pretreatment 

standards: 

(a) Removal of at least 99.0% of total 

mercury from amalgam process 

wastewater and 

(b) Incorporation of the following best 

management practices: 

(1) Scrap amalgam (contact and noncontact), including but not limited to 

dental amalgam from chair-side traps, 

screens, vacuum pump filters, dental 

tools, or collection devices may not be 

flushed down the drain. 

(2) Chair-side traps that may drain to 

a sewer must be cleaned with nonbleach, non-chlorine containing 

cleaners that have a pH of 6 to 8. Such 

cleaning must be conducted at least 

weekly. 

(3) Certification that the BMPs 

specified in paragraphs (b)(1) and (2) of 

this section are being followed is 

deemed to meet these requirements. 

(c) The requirements of paragraph (a) 

of this section may be met by 

installation and operation of at least one 

2008 ISO 11143 certified amalgam 

separator that: 

(1) Is certified to meet a removal 

efficiency of no less than 99.0%; 

(2) Receives all amalgam process 

wastewater; 

(3) Is sized to incorporate all 

wastewater that may pass through it; 

(4) Is inspected at least once per 

month to ensure proper operation and 

maintenance of the separator, including 

confirmation that amalgam process 

wastewater is flowing through the 

retaining cartridge, separator canister, or 

amalgam separating portion of the 

amalgam separator (preventing bypass); 

(5) In the event that the separator is 

found to not be functioning properly, is 

repaired or replaced according to 

manufacturer instructions; and 

(6) Is regularly maintained by 

replacing the amalgam retaining 

cartridge(s), separator canister(s), or 

separator unit(s) whenever the 

collection of retained solids reaches the 

manufacturer’s stated design capacity or 

annually, whichever comes first. 

(d) Dental Dischargers that operate an 

amalgam separator certified under the 

1999 or 2008 ISO 11143 standard 

installed at a dental facility prior to 

October 22, 2014, satisfy the 

requirements of paragraph (a) of this 

section until [DATE 10 YEARS AFTER 

EFFECTIVE DATE OF THE FINAL 

RULE IN THE FEDERAL REGISTER] if 

the existing amalgam separator: 

(1) Receives all amalgam process 

wastewater; 

(2) Is sized to incorporate all amalgam 

process wastewater that may pass 

through it; 

(3) Is inspected at least once per 

month to ensure proper operation and 

maintenance of the separator, including 

confirmation that wastewater is flowing 

through the retaining cartridge, 

separator canister, or amalgam 

separating portion of the amalgam 

separator (preventing bypass); and 

(4) Is regularly maintained by 

replacing the amalgam retaining 

cartridge(s), separator canister(s), or 

separator unit(s) whenever the 

collection of retained solids reaches the 

manufacturer’s rated design capacity or 

annually, whichever comes first. 

§ 441.50 Pretreatment standards for new 

sources (PSNS). 

Except as provided in 40 CFR 403.7 

(removal credits) and 40 CFR 403.13 

(fundamentally different factors), any 

new source subject to this part must 

achieve PSNS as follows: 

(a) Removal of at least 99.0% of total 

mercury from amalgam process 

wastewater and 

(b) Incorporation of the following best 

management practices (BMPs): 

(1) Scrap amalgam (contact and noncontact), including but not limited to 

dental amalgam from chair-side traps, 

screens, vacuum pump filters, dental 

tools, or collection devices may not be 

flushed down the drain. 

(2) Chair-side traps that may drain to 

a sewer must be cleaned with nonbleach, non-chlorine containing 

cleaners that have a pH of 6 to 8. Such 

cleaning must be conducted at least 

weekly. 

(3) Certification that the BMPs 

specified in (1) and (2) of this subpart 

are being followed is deemed to meet 

these requirements. 

(c) The requirements of paragraph (a) 

of this section may be met by 

installation and operation of at least one 

2008 ISO 11143 certified amalgam 

separator that: 

(1) Is certified to meet a removal 

efficiency of no less than 99.0%; 

(2) Captures all amalgam process 

wastewater; 

(3) Is sized to incorporate all amalgam 

process wastewater that may pass 

through it; 

(4) Is inspected at least once per 

month to ensure proper operation and 

maintenance of the separator, including 

confirmation that amalgam process 

wastewater is flowing through the 

retaining cartridge, separator canister, or 

amalgam separating portion of the 

amalgam separator (preventing bypass); 

(5) In the event that the separator is 

found to not be functioning properly, is 

repaired or replaced according to 

manufacturer instructions; and 

(6) Is regularly maintained by 

replacing the amalgam retaining 

cartridge(s), separator canister(s), or 

separator unit(s) whenever the 

collection of retained solids reaches the 

manufacturer’s stated design capacity or 

annually, whichever comes first. 

§ 441.60 Discharge monitoring, reporting, 

and recordkeeping requirements. 

(a) Dental dischargers may comply 

with the following monitoring and 

reporting requirements in lieu of the 

otherwise applicable requirements in 

§ 403.12(b), (d), and (e). 

(1) Baseline report. For existing 

sources, a baseline report must be 


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63286 Federal Register / Vol. 79, No. 204 / Wednesday, October 22, 2014 / Proposed Rules 

submitted within 180 days of the 

effective date of this rule. For new 

sources, a baseline report must be 

submitted at least 90 days prior to 

commencement of discharge. It must 

include: 

(i) The facility name, address, and 

contact information as well as the dental 

license number of all practicing dentists 

at the location. 

(ii) A description of the operation at 

the dental discharger including: 

(A) The total number of chairs, 

(B) The total number of chairs at 

which dental amalgam may be present 

in the resulting wastewater; 

(C) For existing sources, a description 

of any existing amalgam separators 

currently operated to include, at a 

minimum, the make, model, and 

manufacturers recommended frequency 

of container change. If no separators are 

currently employed, indicate none. For 

new sources, a description of any 

planned amalgam separators to include, 

at a minimum, the make, model, and 

manufacturers recommended frequency 

of container change. 

(iii) For existing sources, statement of 

whether or not the facility currently 

employs the best management practices 

(BMPs) specified in § 441.40(b). 

(2) 90-day compliance report. For 

existing sources, a compliance report 

must be submitted within [90 days after 

the final compliance date of this rule]. 

For new sources, a compliance report 

must be submitted within 90 days 

following commencement of the 

introduction of wastewater into the 

publicly owned treatment works 

(POTW). The report must include: 

(i) The facility name, address, and 

contact information as well as the dental 

license number of all practicing dentists 

at the location. 

(ii) A description of the operation at 

the dental office including: 

(A) The total number of chairs, and 

(B) The total number of chairs at 

which dental amalgam may be present 

in the resulting wastewater. 

(C) A description of any existing 

amalgam separators currently operated 

to include, at a minimum, the make, 

model, and manufacturers 

recommended frequency of container 

change. 

(iii) Certification that the design and 

operation of separators meet the 

requirements specified in § 441.40 or 

§ 441.50, as applicable. 

(iv) Certification that the facility is 

employing BMPs specified in 

§ 441.40(b) or § 441.50(b), as applicable. 

(3) Periodic monitoring report. A 

periodic report of ongoing compliance 

must be submitted annually. The reports 

must include: 

(i) The facility name, address, and 

contact information as well as the dental 

license number of all practicing dentists 

at the location; 

(ii) If no changes have occurred since 

submission of the most recent 

compliance submission (e.g. 90-day 

compliance report or periodic 

monitoring report); 

(iii) Certification that the design and 

operation of the separators meets the 

requirements specified in § 441.40 or 

§ 441.50, as applicable and that the 

facility is employing the BMPs specified 

in § 441.40(b) or § 441.50(b), as 

applicable; 

(iv) If changes have occurred since 

submission of the most recent 

compliance submission (e.g. 90-day 

compliance report or periodic 

monitoring report), you must submit the 

updated information required for the 90- 

day compliance report as specified in 

§ 441.60(a)(2). 

(b) If the dental discharger complies 

with the applicable requirements in 40 

CFR part 403 and the monitoring and 

reporting requirements described in 

paragraphs (a)(1) through (3) of this 

section, in addition to the applicable 

pretreatment standards for existing 

sources (PSES) or pretreatment 

standards for new sources (PSNS) in 

§ 441.40 or § 441.50, the dental 

discharger may be considered a Dental 

Industrial User (DIU) by the Control 

Authority; otherwise the Control 

Authority must treat the dental 

discharger as a Significant Industrial 

User (SIU) as defined in 40 CFR 

403.3(v). Reports submitted to comply 

with this section must be signed by the 

responsible corporate officer as defined 

in 40 CFR 403.12(l). 

(c) Dental dischargers must maintain 

on site and available for inspection (in 

either physical or electronic form) the 

following records for a period of three 

years from the date they are created: 

(1) The baseline report required in 

paragraph (a)(1) of this section; 

(2) The 90-day compliance report 

required in paragraph (a)(2) of this 

section; 

(3) The periodic monitoring report 

required paragraph (a)(3) of this section; 

(4) Documentation including the date 

of each visual inspection of the 

amalgam separator(s) as specified in 

§ 441.40(c)(4) or § 441.50(c)(4), 

including records of visual inspections 

of the amalgam separator to ensure that 

the device is not in bypass mode; 

(5) Documentation specifying the date 

of amalgam retaining cartridge 

replacement in accordance with 

§ 441.40(c)(5) or § 441.50(c)(5); and 

(6) Records indicating the date of 

amalgam retaining cartridges are sent off 

site for proper disposal and the shipping 

address of the facility to which amalgam 

retaining cartridges are sent. 

[FR Doc. 2014–24347 Filed 10–21–14; 8:45 am] 

BILLING CODE 6560–50–P 


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