[Federal Register Volume 64, Number 246 (Thursday, December 23, 1999)]
[Proposed Rules]
[Pages 72045-72062]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-33033]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 503

[FRL-6513-3]
RIN 2040-AC25


Standards for the Use or Disposal of Sewage Sludge

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
amend management standards for sewage sludge by adding a numeric 
concentration limit for dioxin and dioxin-like compounds (``dioxins'') 
in sewage sludge that is applied to the land, and monitoring, record 
keeping and reporting requirements for dioxins in sewage sludge that is 
land applied. Today's action also presents the results of risk 
assessments for dioxins in sewage sludge that is applied to the land, 
placed in surface disposal units, or incinerated. Based on these risk 
assessments, the Agency is not proposing additional numeric standards 
or management practice requirements

[[Page 72046]]

for dioxins in sewage sludge that is placed in surface disposal units 
or incinerated.
    EPA is proposing a standard for dioxins in sewage sludge that is 
applied to the land in order to protect public health and the 
environment from unreasonable risks of exposure to dioxins. The 
Agency's risk assessment for land application of sewage sludge 
estimates that sewage sludge with concentrations of dioxins above the 
proposed limit may present an unreasonable cancer risk to specific 
highly exposed individuals. The purpose of this standard would be to 
prohibit land application of sewage sludge containing concentrations of 
dioxins above the limit, and thereby protect the health of highly 
exposed individuals as well as the health of the general population.
    We are also proposing to exclude from the proposed numeric limit 
and monitoring requirements treatment works with a flow rate equal to 
or less than one million gallons per day and certain sludge-only 
entities that receive sewage sludge for further processing prior to 
land application. This exclusion is based on the relatively small 
amount of sewage sludge that is prepared by these facilities and 
entities and, therefore, the low probability that land application of 
these materials could significantly increase risk from dioxins to human 
health or the environment.
    Finally, we are proposing technical amendments to the frequency of 
monitoring requirements. These amendments are intended to clarify but, 
with one exception, not alter the monitoring schedule in the existing 
sludge rule. The one exception would require preparers of material 
derived from sewage sludge to determine the appropriate monitoring 
schedule based on quantity of material derived rather than quantity of 
sewage sludge received for processing.

DATES: Comments must be received or postmarked on or before midnight 
February 22, 2000.

ADDRESSES: Written comments and enclosures should be mailed or hand-
delivered to: Part 503 Sewage Sludge Use or Disposal Rule; Docket 
Number W-99-18, Comment Clerk, Water Docket MC-4101, Environmental 
Protection Agency, 401 M Street, SW, Washington, DC 20460. Comments may 
also be submitted electronically to OW-D[email protected]. For 
additional information see Additional Docket Information section below.

FOR FURTHER INFORMATION CONTACT: Arleen Plunkett, U.S. Environmental 
Protection Agency, Office of Water, Health and Ecological Criteria 
Division (4304), 401 M Street, SW, Washington, DC 20460. (202) 260-
3418.

SUPPLEMENTARY INFORMATION:

I. Regulated Entities
II Additional Docket Information
III. Legal Background
    A. Legal Authority Under Which EPA is Proposing to take Action
    B. Prior Regulation of Sewage Sludge Use or Disposal Under the 
Clean Water Act
IV. Proposed Round Two Sewage Sludge Regulation
    A. Selection of Dioxins for Round Two
    B. Proposed Requirements for Sewage Sludge That Is Land Applied
    1. Overview of Proposed Requirements
    2. Definition of Dioxins
    3. Analytical Methods
    4. Frequency of Monitoring Requirements
    5. Small Preparer Exclusion
    C. Proposal for Sewage Sludge That Is Placed in a Surface 
Disposal Unit or Incinerated in a Sewage Sludge Incinerator
    D. Estimate of Costs
V. Risk Assessment Methodologies and Results
    A. Approach and Assumptions in EPA's Risk Assessments for 
Exposure to Dioxins Resulting from Sewage Sludge Use or Disposal 
Practices
    B. Description of Land Application Risk Assessment
    1. Land Application Exposure Pathways
    2. Key Assumptions for the Land Application Risk Assessment
    3. Land Application Risk Characterization
    C. Description of Surface Disposal Risk Assessment
    1. Surface Disposal Exposure Pathways
    2. Key Assumptions for the Surface Disposal Risk Assessment
    3. Surface Disposal Risk Characterization
    D. Description of Incineration Risk Assessment
    1. Incineration Exposure Pathways
    2. Key Assumptions for the Incineration Risk Assessment
    3. Incineration Risk Characterization
VI. Other Options that EPA Considered
    A. Numeric Standards for All Use or Disposal Practices
    B. Require all Sewage Sludge To Be Landfilled or Surface 
Impounded
    C. No Further Regulation of Sewage Sludge for any Use or 
Disposal Practice
VII. Request for Public Comments
VIII. Regulatory Assessment Requirements
    A. Executive Order 12866, Regulatory Planning and Review
    B. Regulatory Flexibility Act (RFA), as Amended by the Small 
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 
U.S.C. 601 et seq.
    C. Paperwork Reduction Act
    D. Unfunded Mandate Reform Act
    E. Executive Order 13132, Federalism
    F. Executive Order 13084, Consultation and Coordination with 
Indian Tribal Governments
    G. Executive Order 13045, Protection of Children from 
Environmental Health Risks and Safety Risks
    H. National Technology Transfer and Advancement Act
X. List of References

I. Regulated Entities

    Entities potentially regulated by this proposed action are those 
that prepare sewage sludge and/or use or dispose of the sewage sludge 
through application to the land. Regulated categories and entities 
include:

------------------------------------------------------------------------
                Category                  Examples of regulated entities
------------------------------------------------------------------------
State/Local/Tribal Government..........  Publicly owned treatment works
                                          and other treatment works that
                                          treat domestic sewage, that
                                          prepare sewage sludge and/or
                                          apply sewage sludge to the
                                          land.
Federal Government.....................  Federal Agencies with treatment
                                          works that treat domestic
                                          sewage, that prepare sewage
                                          sludge and/or apply sewage
                                          sludge to the land.
Industry...............................  Privately-owned treatment works
                                          that treat domestic sewage,
                                          and persons who receive sewage
                                          sludge and change the quality
                                          of the sewage sludge before it
                                          is used or disposed.
------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. This table lists the types of entities that EPA is now aware 
could potentially be regulated by this action. Other types of entities 
not listed in the table could also be regulated. To determine whether 
your facility or company is regulated by this action, you should 
carefully examine the applicability criteria in Secs. 503.1 and 503.10 
of title 40 of the Code of Federal Regulations. If you have questions 
regarding the applicability of this action to a particular entity, 
consult the person listed in the preceding FOR FURTHER INFORMATION 
CONTACT section.

[[Page 72047]]

II. Additional Docket Information

    The record for this rulemaking has been established under docket 
number W-99-18 and includes supporting documentation as well as the 
printed paper versions of electronic materials. When submitting written 
comments to the Water Docket, (see ADDRESSES section above) please 
reference docket number W-99-18 and submit an original and three copies 
of your comments and enclosures (including references). For an 
acknowledgment that we have received your information, please include a 
self-addressed, stamped envelope. EPA will not accept facsimiles 
(faxes). Comments may also be submitted electronically to: ow-
[email protected]. Electronic comments must be submitted as an 
ASCII, WP5.1, WP6.1or WP8 file avoiding the use of special characters 
and form of encryption. Electronic comments must be identified by 
docket number W-99-18. Comments and data will also be accepted on discs 
in WP5.1, WP6.1, WP8, or ASCII file format. To ensure that EPA can 
read, understand, and, therefore, properly respond to comments, the 
Agency would prefer that commenters cite, where possible, the 
paragraph(s) or sections in the notice or supporting documents to which 
each comment refers. Commentors should use a separate paragraph for 
each issue.
    The record is available for inspection from 9:00 am to 4:00 pm 
Eastern Standard or Daylight time, Monday through Friday, excluding 
legal holidays at the Water Docket, EB 57, USEPA Headquarters, 401 M 
Street, SW, Washington, DC 20460. For access to the docket materials, 
please call 202-260-3027 to schedule an appointment.
    For information on the existing rule in 40 CFR Part 503, you may 
obtain a copy of A Plain English Guide to the EPA Part 503 Biosolids 
Rule on the Internet at http://www.epa.gov/owm/bio.htm or request the 
document (EPA publication number EPA/832/R-93/003) from: Municipal 
Technology Branch, Office of Wastewater Management (4204), Office of 
Water, U.S. Environmental Protection Agency, 401 M Street, SW, 
Washington, DC 20460.

III. Legal Background

A. Legal Authority Under Which EPA Is Proposing To Take Action

    EPA is proposing regulatory amendments to 40 CFR part 503 under 
section 405(d) and (e) of the Clean Water Act (CWA), 33 U.S.C. 1345(d), 
(e). In 1987, Congress amended section 405 and, for the first time, set 
forth a comprehensive program for reducing the potential environmental 
risks and maximizing the beneficial use of sewage sludge. As amended, 
section 405(d) of the CWA requires us to establish numeric limits and 
management practices that protect public health and the environment 
from the reasonably anticipated adverse effects of toxic pollutants in 
sewage sludge. Section 405(e) prohibits any person from disposing of 
sewage sludge from a publicly owned treatment works (POTW) or other 
treatment works treating domestic sewage through any use or disposal 
practice for which regulations have been established pursuant to 
section 405 except in compliance with the section 405 regulations.
    Amended section 405(d) also established a timetable for the 
development of the sewage sludge use or disposal regulations. H. Rep. 
No. 1004, 99th Cong. 2d. Sess. 158 (1986). Section 405(d) calls for two 
rounds of sewage sludge regulations. The first round required EPA to 
establish numeric limits and management practices for toxic pollutants 
we identified which, based on ``available information on their 
toxicity, persistence, concentration, mobility, or potential for 
exposure may be present in sewage sludge in concentrations which may 
adversely affect public health or the environment.'' CWA section 
405(d)(2)(A). The second round concerns toxic pollutants not regulated 
in the first round ``which may adversely affect public health or the 
environment.'' CWA Section 405(d)(2)(B).
    EPA did not meet the timetable in section 405(d) for promulgating 
the first round of regulations, and a citizen's suit was filed to 
require EPA to fulfill this mandate. (Gearhart v. Browner, Civ. No. 89-
6266-HO (D. Ore.)). In accordance with the consent decree entered by 
the court in this case, EPA promulgated the first round of sewage 
sludge regulations, 40 CFR Part 503. 58 FR 9248 (Feb. 19, 1993) 
(``Round One''). The consent decree also established a schedule for 
identifying additional toxic pollutants in sewage sludge and completing 
the second round of regulation under section 405(d)(2)(B) (``Round 
Two''). First, in May 1993, EPA identified 31 pollutants not regulated 
in Round One that we were considering for regulation. In November 1995, 
EPA notified the court that it was revising the original list of 31 
pollutants and considering two pollutant groups for the second round: 
polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/F) and dioxin-
like coplanar polychlorinated biphenyls (PCBs). Under the consent 
decree as modified by court order signed January 5, 1994, the 
Administrator is required to sign a notice for publication proposing 
such regulations no later than December 15, 1999, and to sign a notice 
taking final action on the proposal no later than December 15, 2001.

B. Prior Regulation of Sewage Sludge Use or Disposal Under the Clean 
Water Act

    As noted above, CWA section 405(d)(2)(A) required the first round 
of regulation to be based on ``available information on [the] toxicity, 
persistence, concentration, mobility, or potential for exposure'' of 
toxic pollutants in sewage sludge. After extensive consultation, EPA 
initially selected a list of some 50 pollutants to analyze. We then 
collected available data on those pollutants and developed further 
information on their toxicity, persistence, means of transport, and 
environmental fate. For 40 pollutants, we also developed preliminary 
information on the relative frequency of concentration by analyzing 
their concentrations in the sewage sludge of 43 to 45 POTWs in 40 
cities, which we presented in the report Fate of Priority Pollutants in 
Publicly Owned Treatment Works (the ``40 Cities Study''). Based on this 
information and a screening assessment to determine whether any or all 
of the pollutants may adversely affect human health or the environment, 
we sorted the pollutants into three groups: (1) those which did not 
exceed a human health or environmental criterion at the highest 
concentrations shown in the 40 Cities Study; (2) those for which we 
lacked sufficient data, and (3) those which warranted further risk 
analysis for possible regulation under section 405(d)(2)(A) (58 FR 
9263-9265).
    For the final Round One regulation, we conducted a National Sewage 
Sludge Survey (NSSS) (Notice of Data Availability, 55 FR 47210 (Nov. 9, 
1990)) (USEPA, 1990). We gathered data from sewage sludge samples taken 
at 180 POTWs, as well as survey data from 475 public treatment 
facilities with at least secondary wastewater treatment. We designed 
the NSSS to produce national estimates of (1) concentrations of toxic 
pollutants in municipal sewage sludge, (2) sewage sludge generation and 
treatment processes, (3) sewage sludge use or disposal practices and 
alternative use or disposal practices, and (4) sewage sludge treatment 
and disposal costs. We analyzed the samples of sewage sludge for a 
total of 412 pollutants, including every organic, pesticide, 
dibenzofuran, dioxin and PCB analyte for which EPA had gas

[[Page 72048]]

chromatography and mass spectrometry (GC/MS) standards (58 FR 9268-
9269).
    EPA published the Round One standards (40 CFR part 503) on February 
19, 1993. These regulations established requirements for the final use 
or disposal of sewage sludge under three circumstances:
     When it is applied to the land for a beneficial purpose, 
including use in home gardens;
     When it is placed in a surface disposal site, including 
sewage sludge-only landfills; and
     When it is incinerated.
    For land application, Part 503 set numeric limits for nine heavy 
metals in sewage sludge; established operational standards to reduce or 
eliminate pathogens in sewage sludge and to reduce vector attraction; 
and established management practices to restrict the application rate 
and placement of sewage sludge on the land. Regarding surface disposal, 
part 503 set numeric limits for three metals in sewage sludge, 
established requirements for the placement and management of a surface 
disposal site, and established operational standards to reduce or 
eliminate pathogens in sewage sludge and to reduce vector attraction. 
For incineration in a sewage sludge incinerator (SSI), part 503 
established limits for five pollutants in the sewage sludge fed to a 
SSI and adopted standards under the Clean Air Act for two additional 
pollutants. We also established performance standards for SSIs through 
an operational standard for total hydrocarbon or carbon monoxide 
emissions. Part 503 also allows disposal of sewage sludge in a 
municipal solid waste landfill in accordance with 40 CFR part 258. The 
final rule also requires some monitoring, record keeping and reporting. 
Standards apply to publicly- and privately-owned treatment works that 
generate or treat domestic sewage sludge and to anyone who uses or 
disposes of sewage sludge.
    EPA has amended part 503 several times since its initial 
publication in February 1993. Following promulgation of the Round One 
rule, several petitions for review were filed challenging various 
aspects of the rule. In one petition, several mining and chemical 
concerns challenged the land application molybdenum limits. EPA amended 
Part 503 to delete the cumulative loading rate and pollutant 
concentration rate for molybdenum in sewage sludge to be land applied 
(59 FR 9095, Feb. 25, 1994). Also in that Federal Register notice, EPA 
added continuous monitoring of carbon monoxide as an alternative to 
continuous monitoring of total hydrocarbons in the sewage sludge 
incinerator requirements. In another case, Leather Industries of 
America v. EPA, 40 F.3d 392 (D.C. Cir. 1994), the court remanded 
several of the land application requirements. As a result of that 
decision, EPA deleted all numerical standards for chromium in sewage 
sludge to be land applied and adjusted the Table 3 limit for selenium. 
(60 FR 54764, Oct. 25, 1995). EPA is considering further amendments to 
address the issues remaining from the partial remand as well as other 
issues. EPA most recently amended part 503 to make a number of 
technical amendments, provide some regulatory flexibility, and make the 
sewage sludge incinerator standards self-implementing. (64 FR 42552, 
Aug. 4, 1999).
    For a detailed discussion of the Part 503 Rule, see A Plain English 
Guide to the EPA Part 503 Biosolids Rule, which is available as stated 
in the ADDRESSES section of this preamble.

IV. Proposed Round Two Sewage Sludge Regulation

A. Selection of Dioxins for Round Two

    Chlorinated dioxins are unintentional byproducts of certain 
manufacturing processes and incomplete combustion of organic waste. 
Dioxins are not created in the sewage treatment process; rather, 
treatment works concentrate those dioxins that enter the sewage 
treatment system from other sources. Dioxins present in the influent to 
a wastewater treatment works are partially concentrated in sewage 
sludge and partially discharged in the effluent. The few sewage 
treatment works that incinerate sewage sludge may generate small 
amounts of dioxins and coplanar PCBs during the process of combustion. 
Dioxins are biologically active organic compounds that cause a variety 
of health impacts on mammalian species, including humans, at very low 
and chronic doses. They are found in extremely small quantities in air, 
water and soil; however, they are persistent in the environment and 
bioaccumulate in the foodchain. (USEPA, 1994)
    As described in Section III.B above, when EPA undertook the 40 
Cities Study, we identified one group of pollutants, for which we 
lacked sufficient data. That group included polychlorinated dibenzo-p-
dioxins and polychlorinated dibenzofurans.
    In the subsequent National Sewage Sludge Survey (NSSS) (EPA 1990), 
we obtained additional data, which we used to perform an initial 
statistical screening of 412 additional toxic pollutants detected in 
sewage sludge. We then reviewed the scientific literature for toxicity, 
fate, effect, and transport information for the pollutants identified 
in the initial screening. We decided what pollutants to consider for 
possible regulation by comparing the calculated levels associated with 
adverse effects to the actual level and occurrence data from the NSSS.
    The screening yielded a list of 31 pollutants or pollutant groups 
to be considered for the future regulation. We then conducted a 
Comprehensive Hazard Identification Study (USEPA, 1996), a screening 
type analysis that included dose-response evaluation, exposure 
assessment, and risk characterization. Our goal for the study was to 
identify pollutants that, based on very conservative or worst case 
assumptions, might pose human health risks for a hypothetical 
individual with the greatest possible exposure through any of ten 
pathways. Based on this evaluation, we considered further assessment 
and possible regulation for dioxins/dibenzofurans and coplanar PCBs 
only.

B. Proposed Requirements for Sewage Sludge That Is Land Applied

1. Overview of Proposed Requirements
    Today's action proposes to amend 40 CFR 503.8, 503.9, 503.10, 
503.13, and 503.16 to prohibit land application of sewage sludge that 
contains greater than 300 parts per trillion (ppt) toxic equivalents 
(TEQ) of dioxins. This proposed numeric standard would be expressed as 
0.0003 milligrams TEQ per kilogram dry sewage sludge in 
Sec. 503.13(b)(1) and (b)(3), Tables 1 and 3. See Section V.B. below, 
for an explanation of the risk assessment and how EPA determined that a 
limit of 300 ppt TEQ dioxins in sewage sludge that is land applied is 
protective of public health and the environment.
    We are proposing to define ``dioxins'' to mean 29 specific 
congeners of polychlorinated dibenzo-p-dioxins, polychlorinated 
dibenzofurans, and coplanar PCBs. Today's proposed rule also requires 
monitoring, record keeping, and reporting to ensure that this numeric 
limit (300 ppt TEQ) is met. The proposal specifies two analytical 
methods that would be used to analyze sewage sludge to determine the 
level of dioxins/dibenzofurans and coplanar PCBs in sewage sludge. The 
Agency is proposing two alternative monitoring schedules based on the 
level of dioxins measured in sewage sludge. EPA is also proposing to 
exclude from compliance with the standards for dioxins and the 
monitoring requirement, treatment works that treat domestic sewage and

[[Page 72049]]

that have a flow rate of one million gallons per day or less and 
certain small entities that derive material from sewage sludge received 
from sewage treatment works (``sludge-only entities''). These proposed 
provisions are discussed in detail in the following sections.
2. Definition of Dioxins
    The proposal includes a definition of ``dioxins'' to specify the 
seven 2,3,7,8,-substituted congeners of polychlorinated dibenzo-p-
dioxins (PCDDs), the ten 2,3,7,8-substituted congeners of 
polychlorinated dibenzofurans (PCDFs), and the twelve coplanar PCB 
congeners to which the numeric standard applies. The vast majority of 
information on the toxicity of dioxins relates to the congener 2,3,7,8-
tetrachlorodibenzo-p-dioxin (TCDD). Animals exposed to 2,3,7,8-TCDD 
exhibit a variety of biological responses and adverse effects. These 
include both carcinogenic and non-carcinogenic effects. These effects 
are primarily classified as chronic effects and consequently they are 
generally associated with long term exposure over years and decades. 
Relatively speaking, these exposures and effects are observable at very 
low levels in the laboratory and in the environment when compared with 
other environmental toxicants (USEPA, 1994).
    Studies to elucidate the mechanism of toxicity for 2,3,7,8-TCDD in 
mammalian species have indicated that the overall shape and chlorine 
substitution of this congener are keys to its biological potency. The 
fact that all of the lateral positions (the 2,3,7,8 positions) on the 
multi-ring system are substituted with chlorine and that the overall 
molecule assumes a flat or planar configuration apparently are 
essential factors that make this congener biologically active. Other 
congeners with a similar structure and chlorine substitution pattern 
are assumed to exhibit similar biological properties. These include the 
other six 2,3,7,8-chlorinated substituted dibenzo-p-dioxin congeners, 
the ten 2,3,7,8-chlorinated substituted dibenzofuran congeners and the 
12 coplanar PCB congeners. Coplanar PCB congeners are those congeners 
with no more than one ortho position and both para positions 
substituted with chlorine in the biphenyl ring system and the molecule 
assumes a relatively planar (i.e. flat) configuration.
    The 300 ppt TEQ numeric limit would apply to these 29 congeners in 
ppt TEQ or nanograms TEQ per kilogram of dry sewage sludge. The TEQ 
concentration is calculated by multiplying the concentration of each 
congener in the sewage sludge by its corresponding ``toxicity 
equivalent factor,'' or TEF, and then summing the resulting products 
from this calculation for all 29 congeners. The TEF schemes to be used 
are the International scheme described in USEPA, 1989, for the 17 
2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and 
polychlorinated dibenzofurans and the World Health Organization's TEF 
scheme (Van den Berg, 1998) for the 12 coplanar PCBs. We invite comment 
on the this proposed definition of dioxins.
3. Analytical Methods
    EPA is proposing two methods for analyzing dioxins in sewage sludge 
to be land applied. One method, EPA Method No. 1613, Revision B (1613B) 
would be required for monitoring for the seven dioxin and ten 
dibenzofuran congeners. EPA Method No. 1668 would be required for the 
12 coplanar PCB congeners.
    EPA proposes to use Method 1613, Revision B, ``Tetra-Through Octa-
Chlorinated Dioxins and Furans by Isotope Dilution HRGC/HRMS.'' Method 
1613B is an approved test method (40 CFR part 136) for use in EPA's 
wastewater program for determining dioxins and furans. This test method 
is applicable to both aqueous and solid samples, but was fully 
validated through an interlaboratory study prior to its promulgation 
only for use in wastewater. Method 1613B has not been approved in part 
136 for sewage sludge (62 FR 48394, Sept. 15, 1997).
    EPA proposes to use Method 1668, ``Chlorinated Biphenyl Congeners 
in Water, Soil, Sediment, and Tissue by HRGC/HRMS.'' Method 1668 was 
developed by EPA to analyze coplaner PCBs in a variety of matrices, 
including sewage sludge. Method 1668 was validated in a single 
laboratory and tested in a second laboratory. These data were published 
in the draft method ``Toxic Poly-Chlorinated Biphenyls by Isotope 
Dilution High Resolution Gas Chromatography/High Resolution Mass 
Spectrometry,'' EPA-821-R-97-001, March 1997. EPA revised the original 
version of this method to address additional PCB congeners. Method 
1668A is the state-of-the-art test method for the measurement of PCB 
congeners, including coplanar PCBs; however it is still in draft. 
Method 1668A was validated in a single laboratory and peer reviewed by 
21 laboratories, including EPA's laboratory in Bay St. Louis, 
Mississippi. Although Method 1668A has not gone through a full 
interlaboratory validation study yet, EPA has used this test method in 
monitoring surveys. Both Method 1668 and 1668A are in the docket for 
this rulemaking. If EPA finalizes Method 1668A before EPA takes final 
action on this proposed rulemaking, then the final rule would require 
use of Method 1668A. However, because Method 1668A is not final at this 
time, EPA is proposing the original version of Method 1668 to be used 
to analyze coplanar PCBs in sewage sludge.
    EPA requests public comment on the use of these two test methods 
for compliance with monitoring requirements for sewage sludge. EPA also 
specifically requests comment on the use of Method 1668A for coplanar 
PCBs.
4. Frequency of Monitoring Requirements
    As stated above, EPA is proposing two alternative monitoring 
schedules based on the level of dioxins in sewage sludge to be land 
applied. According to existing information on the amounts of dioxins 
present in sewage sludge, levels can vary considerably from one source 
to another. However, we believe that the level of dioxins in sewage 
sludge, both nationally and from specific sources, is relatively 
constant over time and may possibly be decreasing (U.S. Conference of 
Mayors, 1999). This observation is derived from comparisons of dioxin 
concentrations found in the 1988 NSSS (USEPA, 1990) and the more recent 
Association of Metropolitan Sewerage Agencies (AMSA) survey (Green, et. 
al., 1995), together with anecdotal information from several locations.
    We therefore believe it is appropriate to establish two monitoring 
schedules for dioxins in Sec. 503.16, depending upon the level of 
dioxins found in the initial two years of testing of the sewage sludge. 
Treatment works and other sewage sludge preparers (defined in 
Sec. 503.9(r)) that find the level of dioxin in their sewage sludge to 
be between 300 ppt TEQ and 30 ppt TEQ would be required to monitor 
annually. Treatment works and sludge preparers that measure dioxin 
levels of 30 ppt TEQ or less for two consecutive years would be 
required to monitor every five years thereafter.
    We selected 30 ppt TEQ as the level to allow less frequent 
monitoring since it is a full order of magnitude less than the proposed 
numeric standard of 300 ppt TEQ (i.e., one-tenth). Given the observed 
trends described above, we believe it is unlikely that sewage sludge 
with 30 ppt TEQ or less will exceed the 300 ppt TEQ limit. This 
observation is consistent with: (1) our assumption that dioxins 
primarily enter sewage treatment facilities from diffuse background 
sources which inherently are less subject to short-term spikes in

[[Page 72050]]

pollutant levels than point sources, and (2) a significant measured 
reduction in air emissions of dioxins, which are the principal 
contributors to these diffuse sources, according the Agency's United 
States Dioxin Inventory (USEPA, 1998). Furthermore, any health risks 
associated with dioxin exposure from land application of sewage sludge 
would not be significantly affected over a short period of time such as 
five years, but rather would require long-term exposure at these levels 
to potentially present unreasonable health risks. For these reasons we 
believe a five-year monitoring frequency is appropriate for sewage 
sludge which was last measured at or below 30 ppt TEQ. We are 
specifically requesting comments and additional data on the validity of 
our assumptions concerning rates and degree of changes in levels of 
dioxins in sewage sludge and the reasonableness of the proposed 
monitoring schedule.
    A treatment works or other person who prepares sewage sludge for 
land application would be able to switch to the reduced monitoring 
schedule if tests show that its sewage sludge contained 30 ppt TEQ or 
less in two consecutive annual tests. We believe that two consecutive 
annual tests are reasonable in order to ensure that the level of 
dioxins in the sewage sludge is consistently at or below the 30 ppt TEQ 
level. This is consistent with the existing provision in 
Sec. 503.16(a)(2), which allows the permitting authority to reduce the 
frequency of monitoring after sewage sludge has been monitored for two 
years. We are proposing these frequency of monitoring requirements for 
dioxins to be in a new paragraph (a)(3) in Sec. 503.16. We also 
specifically request comments on whether two consecutive years of 
monitoring results under 30 ppt TEQ should be required before allowing 
a reduced monitoring schedule.
    We are also proposing to amend Sec. 503.16(a) to clarify, but not 
alter, existing frequency of monitoring requirements. We propose to 
separate the existing requirements contained in Sec. 503.16(a)(1) into 
two paragraphs, (a)(1) and (a)(2). Paragraph (a)(1) would contain the 
requirements for monitoring concentrations of pollutants except 
dioxins, and paragraph (a)(2) would contain the requirements for 
monitoring compliance with pathogen reduction and vector attraction 
reduction requirements. Existing Sec. 503.16(a)(2) would be renumbered 
as Sec. 503.16(a)(4), but would be otherwise unchanged. These 
amendments are solely for the purpose of clarity and for expressing 
existing regulatory requirements in plain language, and they are not 
intended to reopen these requirements for comment. We invite comment on 
whether these proposed amendments unintentionally change the substance 
of the frequency of monitoring provisions currently in 
Sec. 503.16(a)(1).
    Finally, we are proposing to amend footnote 1 to Table 1 in 
Sec. 503.16. Currently this footnote states that a person who prepares 
material derived from sewage sludge received from another preparer must 
determine the frequency of monitoring based on the quantity of sewage 
sludge received. Sewage sludge is often mixed with other materials to 
produce the material derived from sewage sludge that is ultimately 
applied to the land. We believe that the frequency of monitoring should 
be based on the quantity of product that is actually applied to the 
land. We therefore propose to amend the footnote to Table 1 to require 
the monitoring schedule to be based on the amount of sewage sludge or 
material derived from sewage sludge to be land applied.
5. Small Preparer Exclusion
    We are proposing in today's action to exclude from the proposed 
requirements relating to dioxins, sewage treatment works with a 
wastewater flow of one million gallons per day (MGD) or less and 
sludge-only entities which prepare 290 dry metric tons or less of 
sewage sludge annually for land application. We estimate that a one MGD 
treatment works produces approximately 290 dry metric tons of sewage 
sludge annually. Sewage sludge from these small preparers would be 
excluded from the limitation on dioxins in sewage sludge; thus these 
small preparers would not be required to monitor for dioxins. Such 
preparers could continue to land apply their sewage sludge with no 
further restriction due to the sludge's dioxin content. Septage pumpers 
and haulers would also not be required to comply with the limitation on 
dioxins and the associated monitoring requirements. (See 58 FR 9362 for 
a discussion of requirements applicable to septage haulers and under 
part 503.)
    We believe that this exclusion is appropriate for several reasons. 
First, the vast majority of land-applied sewage sludge is produced by 
sewage treatment works with flow rates higher than one MGD. According 
to the 1988 NSSS, treatment works with flow rates of one MGD or less 
produce only 135,911 dry metric tons of sewage sludge annually for land 
application, or less than eight percent of the total sewage sludge that 
is land applied on an annual basis. Of the amount of land applied 
sewage sludge produced by those small treatment works, we estimate 
approximately 6800 dry metric tons (5%) contained in excess of the 254 
ppt TEQ PCDD and PCDF. This estimate is based on PCDD and PCDF only 
since the NSSS did not measure coplanar PCBs. Our data indicates that 
sewage sludge containing 300 ppt TEQ dioxins typically would have 254 
ppt TEQ PCDD and PCDF (USEPA, 1990; Green, et al., 1995). Second, the 
probability that this small amount of sewage sludge (i.e., 42 dry 
metric tons per facility annually) could unreasonably increase health 
risks for any individual is extremely small. As further explained in 
Section V.B. of this preamble, the risk assessment assumes a much 
greater amount of sewage sludge is applied to the same piece of land 
over a long period of time. At this much higher application rate, the 
risk assessment estimates unacceptable increase in cancer risk only to 
``high-end'' receptors. We have, therefore, concluded that the amounts 
of land-applied sewage sludge with dioxins in excess of 300 ppt TEQ 
produced by a treatment works with a flow rate of one MGD or less or by 
small sludge-only entities does not pose an unreasonable risk. We 
request comment on our proposal to exclude small preparers from the 
limit for dioxins in sewage sludge to be land applied. We specifically 
invite comment on our proposal to exclude small entities which receive 
and further process sewage sludge prior to land application. We also 
specifically invite comment on how we propose to define such small 
entities.
    We are, however, reserving the option of requiring initial 
monitoring and applying the limit for dioxins for small preparers 
(treatment works and sludge-only entities) which land apply sewage 
sludge. We are requesting information on the dioxin content and land 
application practices (e.g., annual application rates, numbers and 
sizes of sites and the number of applications per site) for sewage 
sludge from treatment works with a flow rate of one MGD or less. We 
specifically invite public comment on whether the Agency should 
promulgate such a requirement.
    We are also proposing to exempt septage pumpers and haulers from 
the proposed limit for dioxins. Septage pumpers and haulers are 
generally small businesses. A typical septage pumper and hauler removes 
between 500 and 1,000 gallons of septage from a residential septic or 
holding tank once every three to five years. The typical maximum 
capacity of a septic tanker that is hauling septage for land 
application is between 2,000 and 4,000

[[Page 72051]]

gallons. The solids content of septage is less than five percent. Using 
the same reasoning as that for sewage treatment works with flows of one 
MGD or less, the maximum amount of septage solids that could be land 
applied on any given area of land on an annual basis would be small. 
Even if this septage contained in excess of 300 ppt TEQ dioxins on a 
dry matter basis, the quantity of dioxins being land applied would be 
insignificant.

C. Proposal for Sewage Sludge That Is Placed in a Surface Disposal Unit 
or Incinerated in a Sewage Sludge Incinerator

    EPA is proposing to take no action to regulate current surface 
disposal or incineration practices for dioxins. As explained below in 
Sections V.C. and D., we do not predict an unreasonable risk of adverse 
effects to human health from cancer as a consequence of either 
placement in a surface disposal unit or incineration in a sewage sludge 
incinerator. Therefore, no additional numeric limit or operational 
standard or monitoring is being proposed for part 503, subparts C and 
E. We invite comment on proposing no action to regulate dioxins in 
sewage sludge that is placed in a surface disposal unit or incinerated 
in a sewage sludge incinerator.

D. Estimate of Costs

    The increased costs which would be imposed by this proposed 
regulation are the costs for initially monitoring for dioxins by all 
land applying treatment works greater than one MGD, annual monitoring 
at those facilities with dioxin levels between 30 ppt TEQ and 300 ppt 
TEQ, and switching to co-disposal with municipal solid waste for 
current land appliers whose sewage sludge contains over 300 ppt TEQ of 
dioxins. We assume that the cost of measuring dioxins in sewage sludge 
is $2000 per sample and the cost to switch to co-disposal with 
municipal solid waste is $189 per dry metric ton in 1998 dollars. We 
estimate that the annualized cost of this regulation nationwide would 
be approximately $18 million. Of this amount, 13 percent is for 
monitoring, and the balance is for switching use or disposal practices.
    The permitting authority, whether Federal or State, should not 
accrue any significant permitting burden as a result of these proposed 
part 503 amendments. The part 503 standards were designed to be self 
implementing and independently enforceable in the absence of a Federal 
permit. These proposed amendments merely add an additional numerical 
standard to the original part 503 rule which was promulgated in 1993.

V. Risk Assessment Methodologies and Results

A. Approach and Assumptions in EPA's Risk Assessments for Exposure to 
Dioxins Resulting from Sewage Sludge Use or Disposal Practices

    The four steps of the risk assessment process include hazard 
identification, dose-response assessment, exposure assessment, and risk 
characterization. We conducted risk assessments for land application of 
sewage sludge, surface disposal of sewage sludge, and incineration of 
sewage sludge in a sewage sludge incinerator. All three risk 
assessments used the same hazard identification and dose-response data 
and assumptions. However, the risk assessments examined different 
exposure pathways and have different risk characterizations. The 
following presents an overview of the approach used for these risk 
analyses and a general description of the assumptions common to all 
three risk assessments.
    Today's proposal is based on assessments of the risks to human 
health posed by dioxins that might be in sewage sludge or sewage sludge 
incinerator emissions using a deterministic risk analysis. A 
deterministic risk analysis produces a point estimate of risk or hazard 
for each person based on using a single value for each parameter in the 
analysis. A parameter is any one of a number of inputs or variables, 
such as soil to plant dioxin uptake coefficients, required for the fate 
and transport and exposure models and equations that EPA uses to assess 
risk. In some cases EPA selects a single set of multiple parameters for 
the purpose of conducting our analyses. We do this to prevent 
inadvertently combining parameters in our analyses in ways that are 
unrealistic. For example, EPA treats environmental setting (location) 
parameters such as climate, depth to groundwater, and aquifer type as a 
single set of parameters. We believe that, for example, allowing the 
climate from one location to be paired with the depth to groundwater 
for another location could result in a scenario that would not occur in 
nature.
    EPA conducts both ``central tendency'' and ``high end'' 
deterministic risk assessments to attempt to quantify the potential 
cancer risk for the ``average'' person in the population (the central 
tendency risk) and the risk or hazard for individuals in small, but 
definable ``high end'' segments of the population (the high end risk). 
For central tendency deterministic risk analyses, we set all parameters 
at their central tendency values. For the sewage sludge risk 
assessments, the central tendency values generally are either mean 
(average) or 50th percentile (median) values.
    We use high end deterministic risk analysis to estimate potential 
risks and hazards for those individuals exposed at the upper range of 
the distribution of exposures. EPA's Guidance For Risk Characterization 
(USEPA, 1995) advises that ``conceptually, high end exposure means 
exposure above about the 90th percentile of the population 
distribution, but not higher than the individual in the population who 
has the highest exposure,'' and recommends that ``the assessor should 
approach estimating high end by identifying the most sensitive 
variables and using high end values for a subset of these variables, 
leaving others at their central values.'' For the sewage sludge high 
end deterministic risk analyses, EPA used exposure pathways that we 
consider to represent how people may encounter the most potential 
exposure to dioxin; chose the 95th percentile concentration (USEPA, 
1999e) of dioxins in sewage sludge and the highest dioxin emitting 
incinerators; and used one other high end exposure factor from the 
Agency's Exposure Factors Handbook (USEPA, 1997) to perform a 
conservative public health analysis.
    The hazard identified for these risk assessments is cancer as a 
human health endpoint from the compounds assessed. We took into account 
the impacts on human cancer risk nationwide. We examined the cancer 
toxicity of 2,3,7,8-TCDD and estimated several dose-response 
relationships for this congener (USEPA, 1994). The toxicity of the 
other congeners included in the current risk assessment are expressed 
in relation to the cancer toxicity of 2,3,7,8-TCDD using guidance we 
published (USEPA, 1989) and from information published in the 
scientific literature (Van den Berg, et. al., 1998).
    Regarding exposure pathways, our evaluation of land application 
considered, among other things, risks of human exposure to dioxins 
through (a) inhaling or ingesting soil fertilized with sewage sludge, 
(b) eating crops grown on this soil or animal products from livestock 
grazed on this soil, and (c) ingesting ground or surface water or 
edible aquatic organisms contaminated as a result of applying sewage 
sludge to land. For surface disposal of sewage sludge, we evaluated the 
human health risks associated with drinking ground water contaminated 
by dioxins or breathing air affected by volatilized dioxins. For 
incineration in a sewage

[[Page 72052]]

sludge incinerator, we evaluated human exposure to dioxins directly 
through inhalation of gases and particles in the emissions from sewage 
sludge incinerators and indirectly by consumption of crops and animal 
products produced on agricultural lands and home gardens affected by 
the deposition of particles from sewage sludge incinerator emissions. 
We were unable to assess the ecological effects for any of the 
practices due to the scarcity of relevant information and evaluation 
methods.
    As indicated above, we attempted to assess the risk both for 
average exposed individuals (AEI) in the population and high end 
exposed individuals (HEI) in the population. In these analyses for the 
hypothetical AEI, average values were used for all parameters to 
capture average risk. For the hypothetical HEI, no more than two high 
end values for exposure variables, such as ingestion rates and 
inhalation rates, were used in the assessment to estimate high end 
risk. These values were obtained in large part from EPA's Exposure 
Factors Handbook (USEPA, 1997).
    You will find below descriptions of routes of exposure (called the 
exposure pathways) through land application, surface disposal, and 
incineration of sewage sludge that we assessed. We then calculated 
risks associated with these pathways by comparing exposures with dose-
response information for the pollutants. The Technical Support 
Documents for this rule making (USEPA, 1999b; USEPA, 1999c; USEPA, 
1999d) contain more details on the final comprehensive exposure pathway 
analyses, including the modeling algorithms and default parameters as 
well as descriptions of major uncertainties and variability.
    Agency experts reviewed the risk assessments used for land 
application and surface disposal. EPA will submit these risk 
assessments to an external peer review panel in accordance with the 
Agency's Peer Review Guidelines during the public comment period for 
this proposed rule. The risk assessment used for incineration was 
submitted to an external peer review panel in accordance with the 
Agency's Peer Review Guidelines. We will consider and address peer 
review comments and public comments on these risk assessments.

B. Description of Land Application Risk Assessment

    We evaluated both agricultural and non-agricultural application 
sites associated with the land application pathways. Agricultural 
sites, which include rangeland and pasture, are land on which a food, 
feed, or fiber crop is grown. Non-agricultural sites include 
reclamation, public contact, and forest sites. The term ``reclamation 
sites,'' defined in 40 CFR 503.11(n), refers to drastically-disturbed 
land that is reclaimed using sewage sludge, including strip mines and 
construction sites. ``Public contact sites'' are those that people 
frequent where contact is likely. Examples of public contact sites are 
parks, ball fields, cemeteries, plant nurseries, turf farms, and golf 
courses (40 CFR 503.11(l)).
1. Land Application Exposure Pathways
    We considered 15 exposure pathways for land application of sewage 
sludge. Five of these pathways were not evaluated since there was 
insufficient data. The pathways that were not evaluated included 
exposure and subsequent toxicity risks from ingestion of feedstuffs 
grown on sewage sludge-amended soils and fed to domesticated farm 
animals (animals commercially produced for human consumption), exposure 
and subsequent toxicity risks from incidental ingestion of sewage 
sludge-amended soils by domesticated farm animals during pasturing and 
grazing, phytotoxicity effects from dioxins in sewage sludge-amended 
soils, and exposure of soil macro organisms and their animal predators 
to dioxins from sewage sludge-amended soils. We invite public comment 
and any information regarding the exposure pathways not evaluated in 
the land application risk assessment.
    Exposure pathways that we fully evaluated for exposure to dioxins 
from land application of sewage sludge include:
     Consumption of commercially grown crops by the general 
population
     Consumption of home-grown crops by home gardeners
     Incidental ingestion of sewage sludge-amended soil by 
children
     Consumption of locally produced meat and dairy products by 
families living outside urban areas (taking into account both forage 
fed to the animals and incidental ingestion of soil by the animals)
     Inhalation of dust from sewage sludge-amended soils by 
farm workers
     Consumption of groundwater, surface water, and aquatic 
organisms affected by leachate and runoff from sewage sludge-amended 
soil
     Inhalation of volatilized pollutants from sewage-sludge 
amended soil
     And ingestion of breast milk by infants in families living 
outside of urban areas
2. Key Assumptions for the Land Application Risk Assessment
    As stated above, we evaluated pathways which represent ways in 
which people can be most exposed to dioxin, in combination with a 
concentration of 300 ppt TEQ of dioxins in sewage sludge and one other 
conservative exposure factor, to ensure a true high-end deterministic 
risk assessment. Some of the exposure factors for land application were 
more conservative than those used for similar incineration pathways. We 
did this because nationwide there are 145 known sewage treatment works 
with sewage sludge incinerators compared to an estimated 4,250 land 
application operations. We estimated the highest concentrations of 
dioxins for land applied sewage sludge from a statistically valid 
sampling of sewage sludge nationwide, while we were able to identify 
and directly monitor the highest dioxin emitting incinerators for this 
risk assessment.
    For land application, we assumed that the highly exposed individual 
lives on the same site for 58 consecutive years. We also assumed that 
sewage sludge at the 95th percentile of concentration of dioxins of 300 
ppt TEQ as estimated in the NSSS and in a data base from a survey 
conducted by the Association of Metropolitan Sewerage Agencies (AMSA) 
(Green, et. al., 1995) is applied to the land every other year for 100 
years at the rate of 10 metric tons per hectare. We note that the AMSA 
survey analyzed for only four of the 12 twelve coplanar PCB congeners. 
However, three of these congeners typically dominate the coplanar PCB 
TEQ values in most environmental samples and are considered adequate 
for generalizing dioxin-like coplanar PCB risk in support of this 
proposed rule. For assessing risks from individual facilities and for 
complying with the provisions of this proposed rule, a full 12 congener 
coplanar PCB analysis is required.
    The risk assessment also assumes that land-applied sewage sludge is 
incorporated into the soil to a depth of 15 centimeters. Our assumption 
is that incorporation into the soil occurs either mechanically at the 
time of application or ``naturally'' over time due primarily to the 
effects of weather and the activity of soil organisms such as worms and 
grubs. The pathways which are based on direct ingestion by grazing 
animals or humans assume that a sludge-soil mixture is ingested. The 
existing part 503 regulation requires a 30-day waiting period prior 
grazing animals after sludge application. We are requesting comment on 
whether we should require

[[Page 72053]]

mechanical incorporation of sewage sludge into the soil, whether 30 
days is a sufficient waiting period to assure adequate natural 
incorporation into the soil, or whether the rule should require a 
longer waiting period.
    Other key assumptions include the following:
     Crops grown on sewage sludge-amended soil are 2.5% of the 
lifetime diet for the general population.
     For a family living in a rural area, 10% of their beef 
diet, 10% of their beef liver diet, 10% of their lamb diet, and 3% of 
their dairy diet comes from local farms that raise animals on sewage 
sludge amended soils.
     Produce grown on sewage sludge-amended soil are 43% to 59% 
of a home gardener's diet.
     Children from ages 1-6 incidentally ingest 0.4 gram of 
sewage sludge-amended soil daily.
     People consume two liters of water and 39 grams of aquatic 
organisms daily from the same source over their lifetimes.
     The nursing period for infants is six months.
    All of the assumptions for the land application risk assessment and 
the basis for these assumptions are described in the land application 
Technical Support Document (TSD) (USEPA, 1999b).
3. Land Application Risk Characterization
    The risk assessment for the exposure pathways described above 
estimates high end risks. Given these conservative assumptions, the 
highest exposure pathways for the hypothetical highly exposed 
individuals for land application are rural families which consume 
products made from locally raised livestock that incidentally ingest 
sewage sludge-amended soil and nursing infants having breast milk from 
hypothetically highly exposed rural family mothers. The resulting high 
end estimate of cancer risk for any such person is 1.7 per 100,000 (1.7 
x 10-5), which is well within the Agency's range of 
acceptable risk of one in one million to one in ten thousand (1 x 
10-6 to 1 x 10-4). However, we estimate that a 
very small percentage of the sewage sludge produced nationwide may 
exceed 300 ppt TEQ dioxin. In order to ensure that any risks associated 
with land application of sewage sludge remain negligible, we propose to 
place a numeric limit of 300 ppt TEQ on the concentration of dioxins in 
sewage sludge which is land applied.

C. Description of Surface Disposal Risk Assessment

    Sewage sludge surface disposal facilities are of two types: (1) 
monofill and (2) surface impoundment. The monofill is a sewage sludge-
only trench fill receiving dewatered sludge with a solids content 
greater than 20%. The surface impoundment receives a continuous inflow 
of sewage sludge with a low solids content of between 2% and 5%. Both 
of these types of surface disposal facilities were subjected to the 
risk assessment for dioxins. The surface impoundment clearly offered 
the greater potential to emit dioxins to the environment and 
subsequently expose an individual to these pollutants. The results of 
the risk assessment with estimated incremental risks to the highly 
exposed individual are based, therefore, on the surface impoundment.
1. Surface Disposal Exposure Pathways
    The only two possible exposure pathways to an HEI are 
volatilization of dioxins from the facility with subsequent inhalation 
of these pollutants and the leaching of dioxins to groundwater with 
subsequent consumption of this groundwater. Based on the required 
management practices of these facilities, there is an insignificant 
chance that dioxins would be released to surface waters even during 
extreme wet weather conditions. Food chain pathways which are critical 
in the land application risk assessment are not relevant.
2. Key Assumptions for the Surface Disposal Risk Assessment
    The HEI for exposure to surface disposal facilities is a person who 
resides in immediate proximity (within 150 meters) to the site. We 
assumed that this person spends his/her entire life at this site. We 
also assumed that this person inhales outdoor air from this site 16 
hours per day and indoor air from within his/her residence adjacent to 
this site for eight hours per day. We set water consumption at two 
liters per day of groundwater obtained within 150 meters from the edge 
of this site at an assumed depth to groundwater of one meter. We 
assumed moderately porous soils for the surface impoundment with no 
synthetic liner to retain leachate (USEPA, 1999a).
3. Surface Disposal Risk Characterization
    The maximum incremental cancer risk to the HEI did not exceed one 
in ten million (1 x 10-7) for either exposure pathway 
(USEPA, 1999b). Dioxins have extremely low volatility and would not be 
expected to offer significant exposure to the HEI through inhalation. 
Also, dioxins do not dissolve readily in water. Even in the absence of 
a liner, combined with high porosity soil and a short distance to 
ground waters as assumed in the risk assessment, only insignificant 
amounts of dioxins could ever reach the groundwater. For these reasons, 
we are proposing no action to regulate dioxins for sewage sludge 
surface disposal.

D. Description of Incineration Risk Assessment

    We used four steps to estimate risks from firing sewage sludge in 
sewage sludge incinerators. First, we estimated the rate at which 
pollutants are emitted from incinerator stacks. Next, we estimated the 
movement of pollutants in air near incinerators, including how much 
pollutant plumes overlap. We then overlaid maps of expected ground-
level concentrations of pollutants and human populations. Finally, we 
determined the extent and nature of resulting health risks of human 
exposure to emitted dioxins.
    The last step was a multi-pathway risk assessment for exposure to 
dioxins that result from the firing of sewage sludge in a sewage sludge 
incinerator. The risk assessment estimated hypothetical average and 
high end risks to the highly exposed sub-populations of farmers and 
home gardeners. We evaluated the risk to the hypothetical highly-
exposed individual who is exposed by both a direct route like 
inhalation and other routes through eating contaminated food. In 
addition, we conducted a probabilistic analysis of uncertainty for the 
home gardener and for the farmer to quantify uncertainty and estimate 
the range of calculated risks possible for the facilities modeled.
    We considered multiple hearth units without afterburners to be the 
worst case technology for sewage sludge incineration and likely the 
highest emitters of dioxins and coplanar PCBs. To provide a high end to 
estimate of the risk from sewage sludge incineration, the analysis 
focused on the six highest emitting incinerators for dioxins/
dibenzofurans and coplanar PCBs in the United States from an initial 
screen of 135 incinerators.
1. Incineration Exposure Pathways
    The assessment considered, but did not evaluate, all 15 exposure 
pathways considered in the land application risk assessment. We 
evaluated those pathways expected to result in the highest risk 
estimates for which data were available. We selected two exposure 
scenarios to represent highly exposed sub-populations that reside

[[Page 72054]]

near sewage sludge incinerators: (1) beef and dairy farmers consuming, 
at recreational fisher levels, fish caught near sewage sludge 
incinerators, and (2) home gardeners consuming as a portion of their 
diet home-grown produce grown near a sewage sludge incinerator. For 
both scenarios, we estimated average and high end exposures for 
children and adults at locations where they are expected to reside. We 
used a geographical information system to identify land uses and 
terrain around facilities, to identify watershed and water body 
parameters to estimate fish and drinking water ingestion risks, and to 
provide census information about farmers and residents exposed to 
incinerator emissions. We estimated numbers of individuals exposed and 
the associated risks for six population age groups.
2. Key Assumptions for the Incineration Risk Assessment
    Many important factors in estimating exposure vary from one 
facility to the next, and as a result, the highest emitting facility 
will not always produce the highest risk. We therefore selected the six 
highest emitting incinerators that also resulted in the highest 
potential inhalation exposures from the initial screening assessment of 
135 incinerators. The variables that are important for exposure 
assessment and considered in the screen include, for example, distance 
to exposed population, activities of the exposed population, effective 
release height of pollutants, and meteorological conditions. We also 
considered emission rates, emission release characteristics, and actual 
populations near the facilities in the initial screening assessment.
    To address high end risk, plausible ranges of values for key 
exposure and model variables were modeled via Monte Carlo procedures to 
estimate the range of possible risk values and their probability of 
occurring. The variables considered for the Monte Carlo modeling were 
identified by sensitivity analyses. The variables were exposure 
duration, beef and dairy consumption, beef and dairy biotransfer 
factors, air to plant transfer, dry sludge throughput, adult inhalation 
rate, and fraction of time an adult is indoors and outdoors.
    The large number of exposure values used in the risk assessment are 
shown in Appendix B of the TSD for incineration (USEPA, 1999c). The 
following is a summary of a few key values:
     Adult body weight of 71.8 kilograms (kg)
     Body weight of a 3-5 year old is 17.5 kg
     Exposure duration for farmer is 17.3 years
     Exposure duration for home gardener is 12 years
     Adult inhalation rate of 13.3 cubic meters each day
     Child 3-5 years old inhalation rate is 8.3 cubic meters 
each day
     Child daily soil ingestion rate of 0.1 grams each day
     Adult daily soil ingestion rate of 0.05 grams each day
     Adult daily fish ingestion rate of 0.162 grams per kg. 
body weight per day
    For the farmer exposure pathway, we evaluated the inhalation of 
vapor and particle-bound pollutants released from the incinerator 
stack(s), soil ingestion, ingestion of homegrown fruits and vegetables, 
ingestion of home-produced beef and dairy products, ingestion of 
drinking water from nearby surface water bodies, and ingestion of fish 
at recreational fisher levels from those water bodies. The home 
gardener pathway included inhalation of vapor and particle-bound 
pollutants, soil ingestion, ingestion of homegrown fruits and 
vegetables, and ingestion of drinking water from surface water bodies. 
For infants in both pathways, breast milk ingestion from an adult's 
exposure to the above pathways is included. Dermal exposure to soil and 
water and consumption of other animal products were not quantified 
since exposures from these pathways are expected to be significantly 
less than the pathways evaluated.
3. Incineration Risk Characterization
    We found that average and high-end risks were higher for the farmer 
than for the home gardener. Estimated risks were higher for individuals 
closer to the facility than farther away. The most significant pathway 
for the farmer was ingestion of home-grown beef and dairy products and 
for the home gardener ingestion of home-grown produce. For infants of 
farmers, the breast milk ingestion pathway is often the most 
significant. For the six facilities, at locations where farmers and 
home gardeners are likely to reside, none of the estimated risk 
exceeded 1 x 10-6, including the estimated risk for infants. 
Based on census data, only extremely small numbers of farm families are 
predicted to be exposed to risk levels near the upper end of the 
predicted range.
    Additionally, the concentration of dioxins in sewage sludge being 
fed into sewage sludge incinerators does not influence the amounts of 
dioxins being emitted from the incinerator. The key factors influencing 
the amount of dioxins being emitted are the combustion conditions in 
the incinerator, incinerator design, and the efficiency and operational 
conditions of any air pollution control devices used on the 
incinerator. The Agency's most recent publicly available Dioxin Source 
Inventory associated with the Draft Dioxin Reassessment (USEPA, 1998) 
estimated that total dioxins (chlorinated dioxins and chlorinated 
dibenzofurans only) being emitted from all of the Nation's sewage 
sludge incinerators was approximately 14.6 grams TEQ per year, a very 
minor fraction of the total North American dioxin inventory. These 
amounts are expected to be further reduced over the next several years 
as the requirement for all sewage sludge incinerators to comply with 
either 100 parts per million (ppm) total hydrocarbons (THC) or 100 ppm 
carbon monoxide (CO) in their emissions is implemented.
    We investigated plans for any future changes for the six multiple 
hearth incinerators (MHI) used in the risk assessment to determine if 
any significant reductions in emissions of dioxin and dioxin-like 
compounds might be expected in the future. Three of the six 
incineration facilities indicated that no changes that might reduce 
emissions were planned in the foreseeable future. They are currently 
meeting the total hydrocarbon emission limitation of 100 ppm.
    Two of the six incineration facilities indicated replacement of the 
existing multiple hearth incinerators is taking place. One of these 
facilities is bringing a fluidized bed incinerator (FBI) on line in the 
first quarter of 2000, which will operate as the primary incinerator. 
The currently operating MHI will be shut down and will remain as a 
backup incinerator, with only occasional use. Tests of FBIs has 
demonstrated more complete destruction of organic compounds than in 
MHI. The other facility expects to shut down its incineration operation 
completely in 2001 and start drying sewage sludge instead. Drying 
involves lower temperatures and no combustion of the sewage sludge, so 
this facility will significantly reduce or eliminate emissions of 
organic pollutants.
    The largest and highest emitting of the incineration facilities 
plans to start to eliminate incineration of sewage sludge in their 
multiple hearth incinerators over the next four to five years. The 
facility is working to evaluate a new high temperature process that 
will convert sludge to a glass-like aggregate. The facility expects to 
submit a permit application within three years to build

[[Page 72055]]

the first aggregate unit. If this initial unit is successful, they will 
submit another permit application to build additional units to replace 
the entire multiple hearth incineration facility. However, if the new 
aggregate process does not prove to be feasible, then this facility 
will continue to use the existing multiple hearth incinerators. The 
facility may consider building FBIs to start replacing aging MHIs.
    On August 4, 1999, we promulgated amendments to the incineration 
subpart of the part 503 standards, 64 FR 42552. The amendments included 
a provision making all sewage sludge incineration requirements self-
implementing. All incinerator owners/operators must now continuously 
monitor for either THC or CO emissions and operate their incinerators 
to limit either THC or CO emissions to 100 ppm or less (40 CFR 
503.40(c), 503.44, 503.45(a)). We will continue to inspect the 
operations and records of these incinerators to assure attainment of 
THC or CO limits.
    Based on the results of the risk assessment for dioxins in sewage 
sludge fired in sewage sludge incinerators and the information we have 
regarding actual and projected incineration of sewage sludge in sewage 
sludge incinerators, we are proposing no national standard for 
incineration of sewage sludge in sewage sludge incinerators. We seek 
comment on this proposal.

VI. Other Options that EPA Considered

A. Numeric Standards for All Use or Disposal Practices

    Under this option, we would propose comprehensive risk-based 
regulations setting numeric standards for dioxins, as well as 
monitoring requirements, reporting, and record keeping provisions for 
all sewage sludge use or disposal practices. We are not proposing this 
option for surface disposal or incineration in a sewage sludge 
incinerator. As previously explained, the risk assessments for surface 
disposal and incineration did not show that the risk from placing 
sewage sludge on a surface disposal site or firing sewage sludge in a 
sewage sludge incinerator, including the highest emitting type of 
sewage sludge incinerator, posed an unreasonable risk to human health. 
We invite public comment on whether EPA should establish numeric limits 
for dioxins in sewage sludge for all use or disposal methods.

B. Require all Sewage Sludge to be Landfilled or Surface Impounded

    Under this option, we would propose a rule under part 503 that 
would require all sewage sludge to be placed in a landfill or surface 
impoundment. The rule would be based on total containment of dioxins in 
sewage sludge and would virtually eliminate all exposure to dioxins 
from sewage sludge. The risk assessments performed did not indicate 
unreasonable risk from exposure to land applied sewage sludge with 
dioxins content of 300 ppt TEQ or less or from exposure to emissions 
from sewage sludge incinerators with any level of dioxins in the 
incinerated sewage sludge. Therefore, we are not proposing this option.

C. No Further Regulation of Sewage Sludge for Any Use or Disposal 
Practice

    We considered this option for land application, as well as for 
surface disposal and incineration. As discussed above, the risk 
assessment shows that sewage sludge with 300 ppt TEQ dioxins that is 
land-applied poses a human cancer risk in excess of one in one hundred 
thousand (1 x 10-5) cancer risk only for highly exposed 
subpopulations using conservative assumptions. The estimated risk of 
1.7 x 10-5 is approximately one-fifth of the background risk 
posed by dioxins from all other sources (USEPA, 1994). However, data 
from the NSSS (USEPA, 1990) show that some treatment works produced 
sewage sludge containing dioxin/dibenzofurans (not including coplanar 
PCBs) as high as 1700 ppt TEQ. Although we have not done a detailed 
risk assessment of the potential impacts of this highest concentration, 
we believe that the incremental cancer risk would likely be on the 
order of one in ten thousand (1 x 10-4) for highly exposed 
subpopulations using conservative assumptions. This level of risk would 
be within the Agency's acceptable range of 1 x 10-6 to 
1 x 10-4. Nevertheless, we believe the better course of 
action is to propose a numeric limit for dioxins in sewage sludge that 
is applied to the land at a level which limits the incremental risk to 
approximately 1 x 10-5 to 2 x 10-5. This approach 
limits incremental risks for dioxins to levels well below background, 
because of concern with multiple sources and possible cumulative 
exposures. The Agency recognizes that its use of ``highly exposed 
individuals'' and other conservative assumptions also builds in some 
margin of safety. Therefore, we request comment on taking no action 
with respect to regulating dioxins for land application of sewage 
sludge.

VII. Request for Public Comments

    While we are requesting comments on all aspects of this proposed 
rule, we hope that public comments will also focus specifically on the 
following aspects of this proposal:
    (1) Establishing of a cap of 300 ppt TEQ dioxins for land applied 
sewage sludge that will protect a highly exposed individual from an 
incremental cancer risk of not greater than 
1.7 x 10-5 (IV.B.1).
    (2) Using EPA Analytical Method 1613B for the chlorinated dioxin 
and dibenzofuran congeners and EPA Analytical Method 1668 or 1668A for 
co-planar PCB congeners (IV.B.3).
    (3) Requiring two consecutive years of monitoring results under 30 
ppt TEQ before allowing a reduced monitoring schedule (IV.B.4).
    (4) Our assumption that the level of dioxins in sewage sludge is 
relatively constant over time and may possibly be decreasing (IV.B.4).
    (5) Whether we have clarified existing monitoring requirements by 
separating Sec. 503.16(a) into two paragraphs or if our proposed change 
unintentionally changes the substance of the frequency of monitoring 
provisions currently in Sec. 503.16(a)(1) (IV.B.4).
    (6) Requesting information on the dioxin content, annual 
application rates, numbers and sizes of sites, and applications per 
site for sewage sludge from treatment works with a flow rate of one MGD 
or less and whether to exempt small treatment works from both the 
initial monitoring requirements and the dioxin limit for land 
application.
    (7) Our proposed designation of small treatment works as one with a 
flow rate of one MGD or less, and our proposed designation of other 
small sludge preparers that are not treatment works as those preparing 
sewage sludge for land application in an amount of 290 dry metric tons 
or less annually (IV.B.5).
    (8) Requesting information on exposure pathways not evaluated, 
including direct risks to livestock, soil organisms, wildlife, and 
plants, resulting from dioxins in sewage sludge that is land applied or 
incinerated (V.B.1, V.D.1).
    (9) Proposing no action in regulating dioxins in sewage sludge that 
is placed in a surface disposal unit or incinerated in a sewage sludge 
incinerator (V.C.3, V.D.3).
    (10) Whether EPA should establish numeric limits for dioxins in 
sewage sludge for all use or disposal methods (VI.A).
    (11) Proposing no action for dioxins in sewage sludge that is land-
applied (VI.C).
    (12) Whether there are any privately-owned treatment works with 
flows greater than one MGD that also have revenues less than $6 
million. If such facilities are operating, we request information on 
flow, revenues, and sludge disposal methods (VIII.B).
    (13) Data on the cost to switch from land application to 
alternative use or disposal practices (compared to our assumption of 
$189 per dry metric ton

[[Page 72056]]

to switch to co-disposal with municipal solid waste) (VIII.B).
    (14) Potential impacts of the proposed rule on small entities and 
on issue related to such impacts (VIII.B).
    (15) The use of the proposed alternative definition of small 
entity--both for this proposed rule and for subsequent rulemakings 
(VIII.B).
    (16) Consensus methods that are suitable for compliance monitoring 
for determining concentrations of dioxins, furans, and coplanar PCBs in 
sewage sludge (VIII.H).

VIII. Regulatory Assessment Requirements

A. Executive Order 12866, Regulatory Planning and Review

    Under Executive Order 12866, [58 FR 51,735 (October 4, 1993)] the 
Agency must determine whether the regulatory action is ``significant'' 
and therefore subject to OMB review and the requirements of the 
Executive Order. The Order defines ``significant regulatory action'' as 
one that is likely to result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or tribal government or communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs or the rights and obligations of recipients 
thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    It has been determined that this rule is not a ``significant 
regulatory action'' under the terms of Executive Order 12866 and is 
therefore not subject to OMB review.

B. Regulatory Flexibility Act (RFA), as Amended by the Small Business 
Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 U.S.C. 601 et 
seq.

    The 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.
    Today's proposal affects two categories of entities: (1) publicly-
owned treatment works (POTWs) owned by local governmental 
jurisdictions, and (2) privately-owned treatment works and sludge-only 
preparers, which are businesses. For this proposal, EPA first assessed 
the effects on small entities using the small entity definition for 
each category as defined in the RFA. EPA also assessed the effects of 
the proposal using the alternative definition for each category of 
small entity that EPA is proposing to establish for this rule. (See the 
discussion under ``Use of Alternative Definition'' later in this 
section.)
    For purposes of assessing the impact of today's proposal on small 
entities, small entities are defined as (1) a small business that meets 
RFA default definitions based on SBA size standards found in 13 CFR 
121.201 (i.e., small refuse systems that have less than $6 million in 
annual revenues); (2) a small governmental jurisdiction that is a 
government of a city, county, town, school district, or special 
district with a population of less than 50,000; and (3) a small 
organization that is any not-for-profit enterprise which is 
independently owned and operated and is not dominant in its field.
    To evaluate the economic impact on small governmental jurisdictions 
subject to today's rule, EPA looked at the effect on municipalities 
owning a POTW that services a population of 50,000 or fewer with 
complete jurisdiction over all indirect discharges to and discharges 
from a treatment works. EPA considers this an appropriate surrogate for 
small governmental jurisdictions. (EPA recognizes that, to the extent a 
governmental jurisdiction may own more than one POTW serving a 
population of 50,000, this evaluation may overstate the number of small 
governmental jurisdictions.)
    Based upon average domestic sewage loadings, a POTW serving a 
population of 50,000 or fewer would correspond to one processing 
approximately five million gallons per day (five MGD) of wastewater. 
EPA's data, however, do not permit it to accurately estimate the number 
of POTWs in a one to five MGD range because EPA collected information 
for the flow range of one MGD to ten MGD. Therefore, in order to 
determine the impact on small governmental jurisdictions, EPA first 
looked at the economic impact of today's proposal on those POTWs with 
one to ten MGD flows who land apply their sewage sludge because the 
proposed dioxin limit would apply only to those POTWs that land apply 
their sewage sludge. EPA estimates that there are approximately 890 
POTWs in the one to ten MGD flow range who land applied their sewage 
sludge. EPA estimated costs for these facilities to comply with the 
proposed monitoring requirements, as described in Section IV.D. EPA 
estimates annual monitoring costs of $2,000 to test for the parameters 
included in today's proposal. The frequency of this monitoring varies, 
depending on the outcome of the test, as explained in Section IV.B.4. 
EPA also estimated incremental disposal costs for between 40 and 50 
facilities in the one to ten MGD flow range with sewage sludge that 
might exceed the proposed 300 ppt TEQ numeric limit for dioxins in 
sewage sludge. EPA estimates that the costs of the proposal would not 
exceed $6 million for the group of POTWs in the one to ten MGD flow 
range.
    For purposes of evaluating the economic impact of this rule on 
small governmental jurisdictions, EPA compared costs with average 
annual revenues for small governmental jurisdictions obtained from the 
1992 Census of Governments. The Census data are reported at a level of 
detail that allow EPA to focus on the small governmental jurisdictions, 
as defined in the RFA. The data further allow EPA to limit the revenue 
information to populations between 10,000 and 50,000, which correspond 
to the small POTWs covered by the proposed rule. (POTWs with flows at 
or below one MGD are exempt from this rule.) The revenues for the 
governmental jurisdictions in the 10,000 to 50,000 population group are 
approximately $57 billion. The costs of the proposed rule represent 
less than 0.01 percent of the entities' revenues. In other words, when 
EPA divided the total compliance costs for the group of POTWs (i.e., 
costs of $6 million) by the revenues for the group of small 
governmental jurisdictions (i.e., revenues of $57 billion), those costs 
are only one, one-hundredth of the revenues. EPA concludes that the 
rule will not have a significant impact on a substantial number of 
small governmental jurisdictions owning these POTWs.
    For privately-owned treatment works, the RFA definition of small 
entity is a small business as defined in U.S. Small Business 
Administration (SBA) regulations at 13 CFR 121.201. Those regulations 
define small refuse systems (Standard Industrial Classification 4953) 
as having less than $6 million in annual revenues. In the Regulatory 
Impact Analysis for the previous Part 503 regulations (EPA 821-R-93-
006, March 1993), EPA concluded that the universe of privately-owned 
treatment works is limited to facilities with wastewater

[[Page 72057]]

flows below one MGD. Today's proposed regulation excludes treatment 
works with flows at or below one MGD; thus, EPA concludes that the 
proposed rule imposes no requirements on small, privately-owned 
treatment works. Although EPA estimates that a privately-owned 
treatment works with annual revenues near $6 million (if one exists) 
corresponds to flows much greater than one MGD, EPA has not identified 
any such treatment works. Theoretically, any privately-owned treatment 
works with flows greater than one MGD and also having revenues less 
than $6 million would be small entities, as defined by the RFA. EPA 
solicits comment on whether such treatment works are operating, and if 
so, requests information on flow, revenues, and sludge disposal 
methods.
    For sludge-only preparers, under the RFA definition cited above, a 
small entity is a preparer with annual revenues of less than $6 
million. EPA data suggest that there are substantially fewer than 100 
sludge-only preparers that are small entities. EPA first considered the 
potential impacts to a subset of small preparers--those with annual 
revenues less than $80,000, which corresponds to production of 
approximately 290 dry metric tons of sewage sludge. EPA equates a 
production level of 290 dry metric tons of sewage sludge to a 
wastewater flow of one MGD. Today's proposed rule excludes this subset 
of very small sludge-only preparers (see section IV.B.5.). Thus, this 
analysis suggests for sludge-only preparers with annual revenues less 
than $80,000, today's proposed rule imposes no requirements. For the 
remaining sludge-only preparers that are also small businesses (by RFA 
definition), i.e., those with annual revenues between $80,000 and $6 
million, EPA estimated the potential impacts as additional monitoring 
costs (see section IV.D.). For the small preparers with revenues 
between $80,000 and $6 million, the estimated impacts will range from 
0.03 to 2.5 percent of revenues. Thus, EPA estimates that there is not 
a significant economic impact on a substantial number of small sludge-
only preparers.
    After considering the economic impacts of today's proposed rule on 
small entities, I certify that this action will not have a significant 
economic impacts on a substantial number of small entities. EPA 
nonetheless has tried to reduce the impacts of this rule on small 
entities. For example, the proposed rule imposes no requirements on 
treatment works (public or private) with flows less than or equal to 
one MGD. This regulatory exclusion markedly limits the number of 
treatment works with monitoring requirements. These smallest POTWs and 
privately-owned treatment works will face no changes in their sludge 
disposal operations. 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.
    Use of Alternative Definition. As noted, EPA is certifying that the 
proposed rule will not have a significant economic impact on a 
substantial number of small entities, using the RFA definitions for 
small entities. However, the RFA authorizes an agency to use 
alternative definitions for each category of small entity, ``which are 
appropriate to the activities of the agency'' after proposing the 
alternative definition(s) in the Federal Register and taking comment. 5 
U.S.C. 601(3)-(5). In addition, to establish an alternative definition 
for small business, agencies must consult with SBA's Chief Counsel for 
Advocacy.
    In today's rule, EPA is proposing to define ``small entity'' for 
purposes of its regulatory flexibility assessments under the RFA as 
follows: EPA is proposing to define ``small governmental jurisdiction'' 
as any municipality or special district operating a POTW with a 
capacity of one MGD or less. Generally flows in this size range 
correspond to service populations of 10,000 or less. EPA also is 
proposing to define ``small business'' as a privately-owned treatment 
works with a capacity of one MGD or less and sludge-sonly preparers 
with finished product amounts of 290 dry metric tons or less of sewage 
sludge. EPA will initiate consultation with the SBA on the alternative 
definition for ``small business'' shortly.
    EPA is proposing these alternative definitions for the purpose of 
consistency within the sewage sludge use or disposal program. When EPA 
published the Standards for the Use and Disposal of Sewage Sludge in 
1993, the Agency used the one MGD definition for its regulatory 
flexibility assessment. At that time (and in the 1990 Notice of Data 
Availability, 55 FR 47210 (Nov. 9, 1990) (USEPA, 1990)), EPA noted the 
well-accepted and frequent use of this definition for small POTWs. The 
existing part 503 land application rule differentiates between 
treatment works with flow rates of one MGD or less and larger treatment 
works. Treatment works with flow rates of one MGD or less are required 
to monitor less frequently and they are excluded from reporting 
requirements.
    In addition to proposing to establish these alternative definitions 
for this rule, EPA also is proposing to establish and use these 
alternative definitions of ``small entity'' for purposes of its 
regulatory flexibility assessments under the RFA for any subsequent 
rulemakings pursuant to section 405 of the Clean Water Act, 33 U.S.C. 
1345 and amendments to 40 CFR 503.
    The Agency is interested in receiving comments on the use of this 
alternative definition of small entity--both for this proposed rule and 
for subsequent rulemakings.
    If EPA had used the alternative definitions in its RFA assessment 
of the impact of today's proposed rule on small entities that would be 
subject to the requirements of the rule, the analysis would have 
supported the same conclusions; i.e., EPA would certify that there is 
no significant economic impact on a substantial number of small 
entities. The proposed rule would not impose any requirements on POTWs 
and privately-owned treatment works with wastewater flows at or below 
one MGD. Consequently, the proposed rule would not have any economic 
impact on small governmental jurisdictions and small businesses that 
are treatment works under the alternative definitions. Similarly, for 
sludge-only preparers, with a small entity definition based on 290 dry 
metric tons of sewage sludge, the proposed rule would not have any 
economic impact on small businesses that are sludge preparers.

C. Paperwork Reduction Act

    The Office of Management and Budget (OMB) approved the information 
collection requirements for existing 40 CFR part 503 under the 
Paperwork Reduction Act, 44 U.S.C. 3501 et seq. (PRA) and assigned OMB 
Control No. 2040-0004.
    The information collection requirements in this proposed rule have 
been submitted for approval to OMB under the PRA. An Information 
Collection Request (ICR) document has been prepared by EPA (ICR No. 
0229.14) and a copy may be obtained from Sandy Farmer by mail at OP 
Collection Strategies Division; U.S. Environmental Protection Agency 
(2822); 401 M St., SW., Washington, DC 20460, by e-mail at 
[email protected], or by calling (202) 260-2740. For 
technical information contact Arleen Plunkett by calling (202) 260-
3418. A copy may also be downloaded off the internet at
http://www.epa.gov/icr.
    This proposed rule will require certain sewage treatment plants 
which produce sewage sludge that is applied to the land and other 
preparers of sewage sludge for application to the land to monitor their 
sewage sludge for dioxins

[[Page 72058]]

and keep records of the analytical results. Entities which monitor for 
dioxin in their sewage sludge will be required to submit these records 
to the permitting authority. This information is needed by the 
permitting authority to ensure compliance with the proposed numerical 
standard for dioxins, thereby assuring that the acceptable incremental 
risk to the highly exposed individual from exposure to dioxins from 
land application of sewage sludge is not exceeded. The responses to the 
collection of information will be mandatory pursuant to section 405(d) 
of the CWA, 33 U.S.C. 1345(d).
    The Agency has estimated the total respondent burden hours and 
costs for these requirements of the proposed rule. Burden means the 
total time, effort, or financial resources expended by persons to 
generate, maintain, retain, or disclose or provide information to or 
for a Federal agency. This includes the time needed to review 
instructions; develop, acquire, install, and utilize technology and 
systems for the purposes of collecting, validating, and verifying 
information, processing and maintaining information, and disclosing and 
providing information; adjust the existing ways to comply with any 
previously applicable instructions and requirements; train personnel to 
be able to respond to a collection of information; search data sources; 
complete and review the collection of information; and transmit or 
otherwise disclose the information.
    The Agency estimates that each respondent, when required to monitor 
for dioxins, will expend a total of one hour to sample their sewage 
sludge, submit this sample to a laboratory for dioxins analysis, 
receive the analytical result from the laboratory, record the result, 
and for certain size entities, report this result to the permitting 
authority. EPA estimates that in the first year that this rule is in 
effect, 1154 facilities will perform dioxin monitoring. The total 
national burden is, therefore, estimated to be 1154 hours. During the 
second year that this rule is in effect, 1096 facilities will be 
performing monitoring for a total burden of 1096 hours. From the third 
year on, the Agency estimates that annually 754 facilities will be 
monitoring for dioxins for a total burden of 754 hours per year.
    Analytical costs per sample are estimated to be $2,000. Therefore 
in year one, total analytical costs to the 1154 respondents are 
estimated to be $2,308,000. Total analytical costs for the 1096 
respondents in year two are estimated to be $2,192,000. Total 
analytical costs for the 754 respondents in year three and beyond are 
estimated to be $1,508,000 annually.
    For the permitting authorities, whether they are the EPA Regional 
Offices or the three States that have received authority to administer 
the part 503 regulatory program (i.e., Utah, Oklahoma, and Texas), the 
Agency estimates that each will be required to spend one hour to review 
the analytical information submitted by the respondents. Therefore, the 
three States identified above and the 10 EPA Regions will expend a 
total of 13 hours annually due to these dioxin monitoring, 
recordkeeping, and reporting requirements.
    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 are listed in 40 CFR part 9 and 48 CFR Chapter 15.

D. Unfunded Mandate Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), P.L. 
104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private sector. Under section 202 of the UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and final rules with ``Federal mandates'' that 
may result in expenditures to State, local, and tribal governments, in 
the aggregate or to the private sector of $100 million or more in any 
one year. Before EPA can promulgate a rule for which a written 
statement is needed, section 205 of the UMRA generally requires EPA to 
identify and consider a reasonable number of regulatory alternatives 
and adopt the least costly, most cost-effective, or least burdensome 
alternative that achieves the objectives of the rule. The provisions of 
section 205 do not apply when they are inconsistent with other 
applicable law. Moreover, section 205 allows EPA to adopt an 
alternative other than the least costly, most cost-effective, or least 
burdensome alternative if the Administrator publishes with the final 
rule an explanation of why that alternative was not adopted.
    Before EPA establishes any regulatory requirements that may 
significantly or uniquely affect small governments, including tribal 
governments, it must have developed under section 203 of the UMRA, a 
small government agency plan. The plan must provide for notifying 
potentially affected small governments, enabling officials of affected 
small governments to have meaningful and timely input in the 
development of EPA regulatory proposals with significant Federal 
intergovernmental mandates, and informing, educating, and advising 
small governments on compliance with the regulatory requirements.
    EPA has determined that today's 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 one year. The highest estimated total costs in 
any one year (1998 dollars) of today's proposed rule are $18 million. 
Thus, today's proposed rule is not subject to the requirements of 
sections 202 and 205 of the UMRA.
    As indicated in the Regulatory Flexibility Act discussion (see 
section VIII. B.), we have determined that this rule will not have a 
significant impact on a substantial number of small governments. 
Additionally, this rule will not uniquely impact small governments 
because it applies to both large and small entities. Today's proposed 
rule exempts wastewater treatment works with flows of less than one MGD 
from the provisions of this proposed rule including monitoring 
requirements. This exemption for these low flow wastewater treatment 
works, therefore, will not create any costs for the small size 
municipalities or small private sector firms that own and operate these 
facilities. Thus, today's proposed rule is not subject to the 
requirements of section 203 of UMRA.

E. Executive Order 13132, Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' is defined in the 
Executive Order to include regulations that 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.''
    Under section 6 of Executive Order 13132, EPA may not issue a 
regulation that has federalism implications, that imposes substantial 
direct compliance costs, and that is not required by statute, unless 
the Federal government provides the funds necessary to pay the direct 
compliance costs incurred by State and local governments, or EPA 
consults with State and local officials early in the

[[Page 72059]]

process of developing the proposed regulation. EPA also may not issue a 
regulation that has federalism implications and that preempts State law 
unless the Agency consults with State and local officials early in the 
process of developing the proposed regulation.
    Section 4 of the Executive Order contains additional requirements 
for rules that preempt State or local law, even if those rules do not 
have federalism implications (i.e., the rules will 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). Those 
requirements include providing all affected State and local officials 
notice and an opportunity for appropriate participation in the 
development of the regulation. If the preemption is not based on 
express or implied statutory authority, EPA also must consult, to the 
extent practicable, with appropriate State and local officials 
regarding the conflict between State law and Federally protected 
interests within the agency's area of regulatory responsibility.
    This proposed rule does not have federalism implications. It will 
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. This proposal would add a 
regulated pollutant to one part of the existing regulatory program, 
however it would not change the existing relationship between federal, 
State, and local officials. Thus, the requirements of section 6 of the 
Executive Order do not apply to this proposed rule.
    This proposed rule will preempt State and or local law that is less 
stringent or inconsistent with these provisions, consistent with CWA 
section 510, 33 U.S.C. 1370. By publishing and inviting comment on this 
proposed rule, EPA hereby is providing State and local officials notice 
and an opportunity for appropriate participation. Thus, EPA has 
complied with the requirements of section 4 of the Executive Order.
F. Executive Order 13084, Consultation and Coordination With Indian 
Tribal Governments
    Under Executive Order 13084, EPA may not issue a regulation that is 
not required by statute, that significantly or uniquely affects the 
communities of Indian tribal governments, and that imposes substantial 
direct compliance costs on those communities, unless the Federal 
governments provides the funds necessary to pay the direct compliance 
costs incurred by the tribal governments, or EPA consults with those 
governments. If EPA complies by consulting, Executive Order 13084 
requires EPA to provide to the Office of Management and Budget, in a 
separately identified section of the preamble to the rule, a 
description of the extent of EPA's prior consultation with 
representatives of affected tribal governments, a summary of the nature 
of their concerns, and a statement supporting the need to issue the 
regulation. In addition, Executive Order 13084 requires EPA to develop 
an effective process permitting elected officials and other 
representatives of Indian tribal governments ``to provide meaningful 
and timely input in the development of regulatory policies on matters 
that significantly or uniquely affect their communities.''
    Today's proposed rule does not significantly or uniquely affect the 
community of Indian tribal governments nor does it impose substantial 
direct compliance costs on them. As indicated in the Regulatory 
Flexibility Act discussion (see section VIII. B.), we have determined 
that this rule will not have a significant impact on a substantial 
number of small governments. The impact on Tribal governments would 
similar to that on small governments. We, therefore, don't expect this 
rule to have a significant impact on tribal governments. Neither do we 
expect this rule will impose substantial direct compliance costs on 
them. Additionally, this rule will not uniquely impact the communities 
of Indian tribal governments because it applies to all entities which 
land apply sewage sludge. Today's proposed rule exempts small 
wastewater treatment works with flows of less than one MGD from the 
provisions of this proposed rule including monitoring requirements. 
This exemption for these low flow wastewater treatment works, 
therefore, will not create any costs for the small size tribal 
governments that own and operate these facilities. Accordingly, the 
requirements of section 3(b) of Executive Order 13084 do not apply to 
this rule.

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

    Executive Order 13045 (62 FR 19885, April 23, 1997) applies to any 
rule that: (1) Is determined to be ``economically significant'' as 
defined under Executive Order 12866, and (2) concerns an environmental 
health or safety risk that EPA has reason to believe may have a 
disproportionate effect on children. If the regulatory action meets 
both criteria, the Agency must evaluate the environmental health or 
safety effects of the planned rule on children and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the Agency.
    This proposed rule is not subject to the Executive Order because it 
is not ``economically significant'' as defined in Executive Order 
12866, and because the Agency does not have reason to believe the 
environmental health and safety risks addressed by this action present 
a disproportionate risk to children. Nevertheless, under EPA policy 
(EPA Policy on Evaluating Health Risks to Children), the risk 
assessment for this rule has addressed potential risk to breast-feeding 
infants and toddlers and the effects of exposure to dioxins. Two 
pathways of exposure are most important in addressing the risk 
potential for children. In the pathway which assumes incidental 
ingestion, we assumed that the toddler from ages one to six eats 0.4 
gram of soil mixed with sewage sludge every day for five years. In the 
breast-feeding infant pathway, the hypothetical highly exposed 
individual is the nursing infant (the nursing period is six months) of 
the rural family mother who eats, on a yearly basis, 10% of her beef, 
10% of her beef liver, 10% of her lamb and 3% of her dairy products 
from animals raised on the farm and fed forage grown on sewage sludge-
amended soils. Moreover, the animals are exposed through ingestion of 
sewage sludge and soils through grazing on pasture. The breast-feeding 
infant pathway was one of the pathways used for setting the proposed 
numeric limit.
    Our assessment of these pathways does not reveal a disproportionate 
environmental health or safety risks to children. Incremental dioxins 
exposure and subsequent cancer risks from sewage sludge use or disposal 
practices are within the risks that would normally be expected and 
within EPA's range of acceptable risk.
    The public is invited to submit or identify peer-reviewed studies 
and data, of which the Agency may not be aware, that assessed results 
of early life exposure to dioxins.

H. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272 
note) directs EPA to use voluntary consensus

[[Page 72060]]

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 the 
Office of Management and Budget (OMB), explanations when the Agency 
decides not to use available and applicable voluntary consensus 
standards. This proposed rule involves technical standards. Therefore, 
the Agency conducted a search to identify potentially applicable 
voluntary consensus standards. However, we identified no consensus 
methods for determination of dioxins, furans or PCBs in solid matrices 
such as sewage sludge. Therefore, EPA proposes to use Method 1613B and 
Method 1668. EPA welcomes comments on this aspect of the proposed 
rulemaking and, specifically, invites the public to identify 
potentially applicable voluntary consensus standards for determination 
of dioxins in sewage sludge and to explain why such standards should be 
used in this regulation.

IX. List of References

Green, et al. 1995. Comments on Estimating Exposure to Dioxin-Like 
Compounds: Review Draft and Addendum.
US Conference of Mayors 1999. The United States Conference of 
Mayors/ Urban Water Council Biosolids Land Application-The Dioxin 
Situation.
USEPA 1989. Interim Procedures for Estimating Risks Associated with 
Exposure to Mixtures of Chlorinated Dibenzo-p-dioxins and -
dibenzofurans (CDDs and CDFs) and 1989 Update. Washington, DC Risk 
Assessment Forum. EPA/625/3-89.016.
USEPA 1990. National Sewage Sludge Survey; Availability of 
Information and Data, and Anticipated Impacts on Proposed 
Regulations; Proposed Rule. Federal Register 55 (218): 47210-47283.
USEPA 1994. Health Assessment for 2,3,7,8-TCDD and Related 
Compounds. External Review Draft. EPA/600/BP-92/001a-c, and, 
Estimating Exposure to Dioxin-Like Compounds. Volume I. Executive 
Summary. Volume II. Properties, Sources, Occurrence, and Background 
Exposures.
Volume III. Site-Specific Assessment Procedures. External Review 
Draft. EPA/600/6-88/005Ca-c. National Center for Environmental 
Assessment. Washington, DC.
USEPA 1995. Policy for Risk Characterization. Memorandum of Carol M. 
Browner, Administrator, March 21, 1995, Washington, DC.
USEPA 1996. Technical Support Document for the Round Two Sewage 
Sludge Pollutants. Office of Science and Technology. Washington, DC. 
EPA-822-R-96-003.
USEPA 1997. Exposure Factors Handbook. National Center for 
Environmental Assessment. Washington, DC. EPA/600/P-95/002F(a-c).
USEPA 1998. The Inventory of Sources of Dioxin in the United States. 
National Center for Environmental Assessment. External Review Draft. 
Washington, DC. EPA/600/P-98/002Aa.
USEPA 1999a. Incremental Costs Associated with Regulating Dioxins 
and PCBs in Biosolids. Office of Science and Technology. Washington, 
DC.
USEPA 1999b. Risk Analysis for the Round Two Biosolids Pollutants. 
Office of Science and Technology. Washington, DC.
USEPA 1999c. Sewage Sludge Incinerators' Dioxin-Like Compound Risk 
Analysis-Draft Technical Documentation. Office of Air Quality 
Planning and Standards. Research Triangle Park, N.C.
USEPA 1999d. Sewage Sludge Incinerators' Dioxin-Like Compound Risk 
Analysis-Draft Addendum with PCB Emissions. Office of Air Quality 
Planning and Standards. Research Triangle Park, N.C.
USEPA 1999e. Pollutant Concentration Percentile Estimates to Support 
Phase II Regulations for Biosolids Use or Disposal. Office of 
Science and Technology. Washington, D.C.
Van den Berg M, et al. 1998. Toxic Equivalent Factors (TEFs) for 
PCBs, PCDDs, and PCDFs for Humans and Wildlife. Environ. Health 
Perspect. 106, 775-792.

List of Subjects in 40 CFR Part 503

    Environmental protection, Frequency of monitoring, Incineration, 
Intergovernmental relations, Land application, Management practices, 
Pathogens, Pollutants, Reporting and recordkeeping requirements, 
Surface disposal, Vector attraction reduction.

    Dated: December 15, 1999.
Carol M. Browner,
Administrator.

    For the reasons set out in the preamble, title 40, chapter I of the 
Code of Federal Regulations is proposed to be amended as follows:

PART 503--STANDARDS FOR THE USE OR DISPOSAL OF SEWAGE SLUDGE

    1. The authority citation for part 503 continues to read as 
follows:

    Authority: Sections 405(d) and (e) of the Clean Water Act, as 
amended by Pub. L. 95-217, Sec 54(d), 91 Stat. 1591 (33 U.S.C. 
1345(d) and (e)); and Pub. L. 100-4 Title IV, Sec. 406(a), (b), 101 
Stat., 71, 72 ( 33 U.S.C. 1251 et seq.).

    2. Add new paragraph (b)(8) to Sec. 503.8 as follows:


Sec. 503.8  Sampling and analysis.

* * * * *
    (b) * * *
    (8) Dioxins. EPA Method No. 1613B for the seven dioxin and ten 
dibenzo- furan congeners. EPA Method No.1668 for the 12 coplanar 
polychlorinated biphenyl congeners. You can purchase a copy of EPA 
Method No. 1613B from the National Technical Information Service (NTIS) 
by requesting NTIS publication number NTIS#: PB93-236024 at 1-800-553-
NTIS (or online at http://www.ntis.gov/). You can also obtain this 
document through the Educational Resources Information Center by 
requesting ERIC publication number W-105 at 1-800-443-ERIC (or online 
at http://www.accesseric.org/). EPA Method Number 1668 (EPA No.821/C-
97-005821/C-97-005) is available on the Office of Water Methods and 
Guidance Diskette 2#. You can request a copy from the EPA Office of 
Water Resource Center at (202) 260-7786 or by sending an e-mail to: 
[email protected].
    3. Redesignate paragraphs (f) through (bb) as (g) through (cc) in 
and add a new paragraph (f) as follows:


Sec. 503.9  General definitions.

* * * * *
    (f) Dioxins means all of the seven 2,3,7,8 chlorinated dibenzo-p-
dioxin congeners, ten 2,3,7,8 chlorinated dibenzofuran congeners, and 
12 coplanar polychlorinated biphenyl congeners as follows:

------------------------------------------------------------------------
                CAS No.                             Congener
------------------------------------------------------------------------
1746-01-6.............................  2,3,7,8-Tetrachlorodibenzo-p-
                                         dioxin
40321-76-4............................  1,2,3,7,8-Pentachlorodibenzo-p-
                                         dioxin
39227-28-6............................  1,2,3,4,7,8-Hexachlorodibenzo-p-
                                         dioxin
57653-85-7............................  1,2,3,6,7,8-Hexachlorodibenzo-p-
                                         dioxin
19408-74-3............................  1,2,3,7,8,9-Hexachlorodibenzo-p-
                                         dioxin
35822-46-9............................  1,2,3,4,6,7,8-Heptachlorodibenzo-
                                         p-dioxin
3268-87-9.............................  1,2,3,4,6,7,8,9-
                                         Octachlorodibenzo-p-dioxin

[[Page 72061]]

 
51207-31-9............................  2,3,7,8-Tetrachlorodibenzofuran
57117-41-6............................  1,2,3,7,8-
                                         Pentachlorodibenzofuran
57117-31-4............................  2,3,4,7,8-
                                         Pentachlorodibenzofuran
70648-26-9............................  1,2,3,4,7,8-
                                         Hexachlorodibenzofuran
57117-44-9............................  1,2,3,6,7,8-
                                         Hexachlorodibenzofuran
72918'21-9............................  1,2,3,7,8,9-
                                         Hexachlorodibenzofuran
60851-34-5............................  2,3,4,6,7,8-
                                         Hexachlorodibenzofuran
67562-39-4............................  1,2,3,4,6,7,8-
                                         Heptachlorodibenzofuran
55673-89-7............................  1,2,3,4,7,8,9-
                                         Heptachlorodibenzofuran
39001-02-0............................  1,2,3,4,6,7,8,9-
                                         Octachlorodibenzofuran
32598-13-3............................  3,3',4,4'-Tetrachlorobiphenyl
70362-50-4............................  3,4,4',5-Tetrachlorobiphenyl
57465-28-8............................  3,3',4,4',5-Pentachlorobiphenyl
32598-14-4............................  2,3,3',4,4'-Pentachlorobiphenyl
31508-00-6............................  2,3',4,4',5-Pentachlorobiphenyl
65510-44-3............................  2',3,4,4',5-Pentachlorobiphenyl
74472-37-0............................  2,3,4,4',5-Pentachlorobiphenyl
32774-16-6............................  3,3',4,4',5,5'-
                                         Hexachlorobiphenyl
38380-08-4............................  2,3,3',4,4',5-Hexachlorobiphenyl
69782-90-7............................  2,3,3',4,4',5'-
                                         Hexachlorobiphenyl
52663-72-6............................  2,3',4,4',5,5'-
                                         Hexachlorobiphenyl
39635-31-9............................  2,3,3',4,4',5,5'-
                                         Heptachlorobiphenyl
------------------------------------------------------------------------

* * * * *
    4. Amend Sec. 503.10 by redesignating paragraph (a) as (a)(1) and 
adding a title to paragraph (a) before (a) (1); and adding paragraph 
(a)(2) as follows:


Sec. 503.10  Applicability.

    (a) General applicability of Subpart B--Land Application.
* * * * *
    (2) The pollutant limits in Sec. 503.13(a)(1), (a)(2)(ii), (a)(3), 
and (a)(4)(i) do not apply to sewage sludge prepared by, and the 
monitoring requirements in Sec. 503.16(a)(3) do not apply to:
    (i) A treatment works that treats domestic sewage with a flow rate 
equal to or less than one million gallons per day or;
    (ii) A person who prepares sewage sludge or who derives a material 
from sewage sludge in an amount equal to or less than 290 dry metric 
tons per year.
* * * * *


Sec. 503.13  [Amended]

    5. Amend Sec. 503.13 by adding a sentence after the header to 
paragraph (a) and adding an entry for ``Dioxins'' in alphabetical order 
in paragraph (b)(1) and adding an entry for ``Dioxins'' in alphabetical 
order in paragraph (b)(3) as follows:


Sec. 503.13  Pollutant limits.

    (a) Sewage sludge. Except as provided in Sec. 503.10(a)(2), the 
following pollutant limits apply to sewage sludge that is applied to 
the land.
* * * * *
    (b) * * *
    (1) * * *

             Table 1 of Sec.  503.13--Ceiling Concentrations
------------------------------------------------------------------------
                                                 Ceiling  concentration
                  Pollutant                         (milligrams per
                                                     kilogram) \1\
------------------------------------------------------------------------
 
 
                                * * * * *
Dioxins (defined in Sec.  503.9(f)...........  0.003 TEQ
 
                                * * * * *
------------------------------------------------------------------------
\1\ Dry weight basis.

* * * * *
    (3) * * *

            Table 3 of Sec.  503.13--Pollutant Concentrations
------------------------------------------------------------------------
                                                    Monthly average
                  Pollutant                    concentration (milligrams
                                                   per kilogram) \1\
------------------------------------------------------------------------
 
                                * * * * *
Dioxins (defined in Sec.  503.9(f))..........  0.0003 TEQ
 
                                * * * * *
------------------------------------------------------------------------
\1\ 1 Dry weight basis.


[[Page 72062]]

* * * * *
    6. Revise (a) of Sec. 503.16 as follows:


Sec. 503.16  Frequency of monitoring.

    (a) Sewage sludge. You must monitor for pollutants in sewage 
sludge, pathogen density and vector attraction reduction according to 
the following schedule:
    (1) For all pollutants except dioxins listed in Sec. 503.13(b)(1) 
Table 1 and (b)(3) Table 3 and all pollutants listed in 
Sec. 503.13(b)(2) Table 2 and (b)(4) Table 4, you must monitor as 
provided in Table 1 of this section.
    (2) For pathogen density requirements in Sec. 503.32(b)(2) through 
(b)(4) and the vector attraction reduction requirements in 
Sec. 503.33(b)(1) through (b)(8), you must monitor as provided in Table 
1 of this section.

                          Table 1 of Sec.  503.16
------------------------------------------------------------------------
  Amount of sewage sludge \1\ (metric
        tons per 365 day period)                    Frequency
------------------------------------------------------------------------
Greater than zero but less than 290....  Once per year.
Equal to or greater than 290 but less    Once per quarter (four times
 than 1,500.                              per year).
Equal to or greater than 1,500 but less  Once per 60 days (six times per
 than 15,000.                             year).
Equal to or greater than 15,000........  Once per month (12 times per
                                          year).
------------------------------------------------------------------------
\1\ Either the amount of bulk sewage sludge applied to the land (dry
  weight basis), or the amount of sewage sludge or material derived from
  sewage sludge sold or given away in a bag or other container prepared
  by a person who prepares sewage sludge for application to the land
  (dry weight basis).

    (3) Except as provided in Sec. 503.10(a)(2), for dioxins listed in 
Sec. 503.13(b)(1) and (3), you must monitor your sewage sludge 
annually, as of [one year after effective date of final rule].
    (i) If the level of dioxins in your sewage sludge is above 30 ppt 
TEQ but below 300 ppt TEQ, then you must monitor for dioxins annually.
    (ii) If the level of dioxins in your sewage sludge is at or below 
30 ppt TEQ for any two consecutive years, then you may reduce the 
frequency of monitoring to once every five years.
    (iii) If you have reduced the frequency of monitoring under 
paragraph (a)(3)(ii) of this section and the level of dioxins in your 
sewage sludge exceeds 30 ppt TEQ, you must resume monitoring your 
sewage sludge annually.
    (4) After the sewage sludge has been monitored for two years at the 
frequency in Table 1 of this section, the permitting authority may 
reduce the frequency of monitoring for the pollutant concentrations and 
for the pathogen density requirements in Sec. 503.32(a)(5)(ii) and 
(a)(5)(iii).
* * * * *
[FR Doc. 99-33033 Filed 12-22-99; 8:45 am]
BILLING CODE 6560-50-U