United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
research Triangle I'ark NC 27711
EPA-453\R-93-035
February 1994
Documentation of De minimis
Emission Rates- Proposed
40 CFR Part 63, Subpart B
Background Document
Emission Standards Division
-------
Documentation of De mini mis
Emission Rates- Proposed
40 CFR Part 63, Subpart B
Background Document
Prepared by:
Jane Caldwell-Ken kel
and
Tim Smith
Program Intergration and Health Section
Pollutant Assessment Branch
Office of Air Quality Plannint and Standards
-------
-------
2
INTRODUCTION
Section 112(g) of the Clean Air Act ("the Act"), as amended
in 1990, requires control technology determinations for
"modifications" to plant sites that are major sources of
hazardous air pollutants (HAP). A "modification" is defined in
section 112(a) of the Act as a physical change or change in the
method of operation that causes an emission increase above de
minimis levels. The EPA is proposing a rule that provides
guidance for the implementation of the section 112(g)
requirements, including those for "modifications." One important
aspect of the proposed rule is a table (included in the proposed
rule as $63.44) of de minimis emission rates. The preamble to
the proposed rule discusses the overall risk management framework
for the proposed de minimis levels, and discusses the types of
data and analyses used by the EPA in developing them. The
purpose of this document is to provide further supporting
information for the de minimis emission rates, cited in the
section 112(g) proposed rule, such that reviewers will be
provided complete documentation of the basis for each value.
This background document contains seven sections and two
appendixes. Section I contains a discussion of the risk
management decisions contained in the methodology used to derive
de minimis levels. Section II is a summary of the proposed de
minimis levels and their basis. Section III contains a
description of methods used to determine de minimis levels for
"known, probable, or possible" human carcinogens while section IV
-------
3
contains a parallel discussion of documents, data, and
methodology used to define de minimis emission rates for effects
other than cancer. De minimis levels for pollutants of "high-
concern" under the Great Waters Program [section 112(m)] are
discussed in section V with special case pollutants which are
considered unrankable are discussed in section VI. The
provisions in the proposed rule to allow States to develop
programs for establishing case-by-case de minimis values are
found in section VII. Appendix A contains the results of a
dispersion analysis using a model plant to determine emission
rates. Appendix B contains data concerning fine mineral fibers
referred to in section VI.
I. GENERAL CONSIDERATIONS IN ESTABLISHING DE MINIMIS VALUES
A. De Minimis as a Risk Management Decision.
The statutory language contained in section 112(g) of the
Act does not specifically describe the criteria for setting de
minimis in the context of the modification provisions. However,
the EPA believes there are general principles which have been
established by the courts and by the Act that provide guidance
for the establishment of de minimis emission rates.
In general, the concept of de minimis has been used by the
courts for providing authority to regulatory agencies to make
exceptions for regulation when the regulatory burdens of those
affected by the rule would "yield a gain of trivial or no value."
(For a thorough discussion of these principles, readers can
-------
4
review the June 18, 1979 Alabama Power v. Costle court decision,
13 ERG 61225). The concept of de minimis, in the context of
section 112(g), is intended to prevent trivial emissions
increases to be considered "modifications" subject to regulation
and needlessly drain administrative resources. In order to
establish a de minimis emission rates under section 112(g), the
EPA seeks to demonstrate levels of emission increases that would
result in a trivial risk to the public health.
The EPA believes that Congress provided guidance as to what
may be considered a trivial risk to human health in sections
112(c)(9) and 112(f) of the Act. Under sections 112(c)(9),
source categories face no regulation and under section 112(f)
residual risk is assumed to be negligible when (a) emissions of a
known, probable, or possible human carcinogen could cause a
lifetime risk of cancer of less than one in a million to the
maximally exposed individual and (b) emissions of a non-
carcinogen would not exceed a level which is adequate to protect
public health with an "ample margin of safety" and would not
result in adverse environmental impacts.
In establishing the de minimis emission rates, the EPA
believes that where information is available to determine (1) an
exposure level which results in a one-per-million cancer risk
level, or (2) an exposure level which constitutes an "ample
margin of safety" level, this information should serve as the
basis for the de minimis levels. The risk management decisions
to use these two criteria to determine de minimis emission rates
-------
5
are fundamental assumptions in the methodology that follows.
For pollutants where insufficient dose-response information
is available to determine the exposure level associated with
either a one-per-million cancer risk or an "ample margin of
safety" for noncancer effects, the proposed rule contains default
values which reflect risk management decisions for establishing
the de minimis emissions rates.
An important risk management decision for establishing de
minimis levels under section 112(g) was to "cap" de minimis
emission rates at 10 tons per year. An emission rate of any HAP
of at least ten tons per year is considered a "major" amount
according to the definitions in section 112(a) of the Act. The
EPA believes that it would be difficult to support the
designation of a "trivial" level of emissions of an air pollutant
that is considered "major" by the guiding legislation.
Finally, the risk management process for establishing de
minimis values for the proposed rule for section 112(g) gave
consideration the interim nature of the section 112(g)
requirements. It is important to note that the de minimis rates
listed under section 112(q) are not intended to establish a
precedent for use in other 112 programs. Specifically, the
values themselves are not intended to be used as a precedent for
setting residual risk standards under section 112(f) of the Act
or for establishing criteria for removing source categories from
the list pursuant to section 112(cW9). However the principles
involved (i.e., use of one in a million cancer risk) and some of
-------
6
the supporting data (i.e., unit risks for cancer or RfCs) may be
applicable to other programs wishing to determine trivial levels
for regulatory purposes.
B. De Minimis Rates. Ambient Concentrations vs. Emission
Rates.
The EPA considered expressing de minimis values as ambient
concentrations rather than emission rates. Under this approach,
the applicant would be required to determine whether an emission
increase would cause an increase in ambient concentration that
would exceed the de minimis level. Such an approach would
require the applicant or the reviewing authority to perform a
dispersion calculation for each proposed release, which would add
an additional complicated step in the process. An individual
dispersion analysis would not be required if the de minimis
values were expressed as emission rates and based on a standard
model dispersion scenario. Consistent with conclusions reached
under the prevention of significant deterioration (PSD) program,
the EPA believes that the added complexity of the dispersion
analysis for each emission increase is not warranted. The
proposed subpart B regulation does, however, provide State
agencies with the option of providing for de minimis
determinations based on set ambient de minimis concentrations and
using a case-by-case dispersion analysis.
-------
7
II. SUMMARY OF DE MINIMIS VALUES
Section 112(b) of the Act contains a list of 189 HAP which
are to be regulated under the "modification" requirements of
section 112(g). This list of HAP includes 172 individual
pollutants and 17 chemical groups. The 17 chemical groups are
as follows: antimony compounds, arsenic compounds (inorganic
including arsine), beryllium compounds, chromium compounds,
cobalt compounds, coke oven emissions, cyanide compounds, glycol
ethers, lead compounds, manganese compounds, mercury compounds,
fine mineral fibers, nickel compounds, polycyclic organic matter,
radionuclides (including radon), and selenium compounds. As
discussed in the preamble to the proposed subpart B, the EPA
believes that where toxicity differences exist between members in
each grouping, the assignment of de minimis values should be
subdivided accordingly. The documentation for subdividing the
chemical groupings can be found in a technical background
document for another portion of the subpart B rule (the Draft
Technical Background Document to Support Rulemakinq Pursuant to
the Clean Air Act Section 112(q). Ranking of Pollutants with
Respect to Hazard to Human Health. EPA 450/3-92-010).
Table 1, below, contains the individual HAP, and chemical
groupings, and sub-groupings for which de minimis emission rates
have been proposed for section 112(g). Sub-groupings of
"radionuclides" are contained elsewhere and discussed in section
six of this document (subpart B and I, and Appendix E of 40 CFR
part 61). De minimis levels for fine mineral fibers are also
-------
7a
Table
112(g) DE MIIMIMIS LEVELS
CAS Chemical Name
OE MINIMIS
LEVEL
(TONS/YR)
BASJS
57147 1,1-Dimethyl hydrazine
79005 1,1,2-Trichloroethane
79345 1,1,2,2-Tetrachloroethane
96128 1,2-Dibromo-3-chloropropane
122667 1,2-D/phenylhydrazine
106887 1,2-Epoxybutane
75558 1,2-Propylenimine (2-Methyl aziridine)
120821 1,2,4-Trichlorobenzene
106990 1,3-Butadiene
542756 1,3-Dichloropropene
1120714 1,3-Propane sultone
106467 1,4-Dichlorobenzene(p)
123911 1,4-Dioxane (1,4-Diethyleneoxide)
53963 2-Acetylaminofluorine
532274 2-Chloroacetophenone
79469 2-Nitropropane
540841 2,2,4 - Trimethylpentane
1746016 2,3,7,8-Tetrachlorodibenzo-p-dioxin
584849 2,4 - Toluene diisocyanate
51285 2,4-Dinitrophenol
121142 2,4-Dinitrotoluene
94757 2,4-D, salts, esters(2,4-Dichlorophenoxy acetic acid)
95807 2,4-Toluene diamine
95954 2,4,5-Trichlorophenol
88062 2,4,6-Trichlorophenol
91941 3,3-Oichlorobenzidene
119904 3,3'-Dimethoxybenzidine
119937 3,3'-Dimethyl benzidine
92671 4-Aminobiphenyl
92933 4 - Nitrobiphenyl
, 100027 4 -Nitre-phenol
101144 4,4-Methylene bis(2-chloroaniline)
101779 4,4'-Methylenedianiline
534521 4,6-Dinitro-o-cresol, and salts
75070 Acetaldehyde
60355 Acetamide
A75058 Acetonrtrile
^98862 Acetophenone
'07028 Acrolein
0.008
1
0.3
0.01
0.09
1
0.003
10
0.07
1
0.03
3
6
0.005
0.06
1
5
6E-07
0.1
1
0.02
10
0.02
1
6
0.2
0.1
0.008
1
1
5
0.2
1
0.1
9
1
4
1
0.04
UR
UR
UR
UR
UR
DEF=1
UR
CAP-RfC
UR
DEF=1
UR
UR
UR
UR
RfC
DEF=1
DEF=5
UR
ACUTE
CS
UR
CS
UR
DEF=1
UR
UR
UR
UR
DEF=1
DEF=1
DEF=5
UR
DEF=1
ACUTE
UR
DEF=1
RfC
CS
RfC
-------
0 112(g) DE MINIMIS LEVELS
CAS Chemical Name
#
79061 Acrylamide
791 07 Acrylic acid
107131 Acrylonitrile
107051 Ally! chloride
62533 Aniline
71432 Benzene
92875 Benzidine
98077 Benzotrichloride
1 00447 Benzyl chloride
57578 beta-Propiolactone
92524 Biphenyl
117817 Bis(2-ethylhexyl)phtnalate (DEHP)
542881 Bis(chloromethyl) ether
75252 Bromoform
1 56627 Calcium cyanamide
1 05602 Caprolactam
1 33062 Captan
63252 Carbaryl
75 150 Carbon disulfide
56235 Carbon tetrachloride
463581 Carbonyl sulfide
1 20809 Catechol
133904 Chloramben
57749 Chlordane
7782505 Chlorine
791 1 8 Chloroacetic acid
1 08907 Chlorobenzene
51 01 56 Chlorobenzilate
67663 Chloroform
1 07302 Chloromethyl methyl ether
1 26998 Chloroprene
1319773 Cresols/Cresylic acid (isomers and mixture)
95487 o-Cresol
108394 m-Cresol
106445 p-Cresol
98828 Cumene
334883 Diazomethane
132649 Dibenzofuran
72559 DDE (p.p'-Dichlorodiphenyldichloroethylene)
84742 Dibutylphthalate
1 1 1444 Dichloroethyl ether (Bis(2-chloroethyl)ether)
62737 Dichlorvos
1 1 422 Diethanolamine
64675 Diethyl sulfate
60117 Dimethyl aminoazobenzene
79447 Dimethyl carbamoyl chloride
681 22 Dimethyl formamide
131113 Dimethyl phthalate
DE MINIMIS
LEVEL
(TONS/YR)
0.02
0.6
0.3
1
1
2
0.0003
0.006
0.1
0.1
10
5
0.0003
10
10
10
10
10
1
1
5
5
1
0.01
0.1
0.1
10
0.4
0.9
0.1
1
1
1
1
1
10
1
5
0.01
10
0.06
0.2
5
1
1
0.02
1
10
BASIS
<
UR
RfC
UR
DEF=1
UR
UR
UR
UR
ACUTE
ACUTE
CS
UR
UR
CAP-UR
CS
CS
CAP-UR
CS
CS
UR
DEF=5
DEF=5 *
DEF=1 J
GWP
ACUTE
ACUTE
CS
UR
UR
ACUTE
DEF=1
DEF=1
DEF=1
DEF=1
DEF=1
CS
DEF=1
DEF=5
GWP
CS
UR
UR
DEF=5
DEF=1
DEF=1
UR
DEF=1 \
CS
-------
7c
0 112(g) DE MINIMIS LEVELS
CAS Chemical Name
#
77781 Dimethyl sulfate
1 06898 Epichlorohydrin
140885 Ethyl acrylate
10041 4 Ethyl benzene
51796 Ethyl carbamate (Urethane)
75003 Ethyl chloride
1 06934 Ethylene dibromide (Dibromoethane)
1 07062 Ethylene dichloride (1 ,2-Dichloroethane)
107211 Ethylene glycol
151564 Ethylene imine (Aziridine)
7521 8 Ethylene oxide
96457 Ethylene thiourea
75343 Ethylidene dichloride (1,1-Dichloroethane)
50000 Formaldehyde
76448 Heptachlor
1 1 8741 Hexachlorobenzene
87683 Hexachlorobutadiene
77474 Hexachlorocyclopentadiene
67721 Hexachloroethane
822060 Hexamethylene,-1 , 6 -diisocyanate
680319 Hexamethylphosphoramide
110543Hexane
302012 Hydrazine
764701 0 Hydrochloric acid
7664393 Hydrogen fluoride
1 2331 9 Hydroquinone
78591 Isophorone
58899 LJndane (hexachlorcyclohexane, gamma)
1 0831 6 Maleic anhydride
67561 Methanol
72435 Methoxychlor
74839 Methyl bromide (Bromomethane)
74873 Methyl chloride (Chloromethane)
71556 Methyl chloroform (1,1,1 -Trichloroethane)
78933 Methyl ethyl ketone (2-Butanone)
60344 Methyl hydrazine
74884 Methyl iodide (lodomethane)
108101 Methyl isobutyl ketone
624839 Methyl isocyanate
80626 Methyl methacrylate
1634044 Methyl tert-butyl ether
12108133 Methylcyclopentadienyl manganese
75092 Methylene chloride (Dichloromethane)
1 01 688 Methylene diphenyl diisocyanate
91203 Naphthalene
98953 Nitrobenzene
62759 N-Nitrosodimethylamine
69892 N-Nitrosomorpholine
DE MINIMIS
LEVEL
(TONS/YR)
0.1
2
1
10
0.8
10
0.1
0.8
10
0.003
0.1
0.6
1
2
0.02
0.01
0.9
0.1
5
0.02
0.01
10
0.004
10
0.1
1
10
0.01
1
10
10
10
10
10
10
0.06
1
10
0.1
10
10
0.1
10
0.1
10
1
0.001
1
BASIS
ACUTE
RfC
UR
CAP-RfC
UR
CAP-RfC
UR
UR
CS
UR
ACUTE
UR
DEF=1
UR
UR
GWP
UR
ACUTE
UR
RfC
RfC
CAP-RfC
UR
CAP-RfC
ACUTE
DEF=1
CAP-UR
GWP
CS
CS
CS
RfC
CAP-UR
CS
CAP-RfC
UR
DEF=1
CS
ACUTE
CS
CAP-RfC
ACUTE
CAP-UR
RfC
CS
CS
UR
DEF=1
-------
7e
0 1 1 2(g) DE MINIMIS LEVELS
CAS Chemical Name DE MINIMIS
# LEVEL
(TONS/YR)
Beryllium salts
Cadmium compounds
13061 8 Cadmium oxide
Chromium compounds (except Hexavalent and Trivalent)
Hexavalent Chromium compounds
Trivalent Chromium compounds
1 0025737 Chromic chloride
744084 Cobalt metal (and compounds, except those specifically listed)*
10210681 Cobalt carbonyl
62207765 Fluomine
Coke oven emissions
Cyanide compounds (except those specifically listed)*
143339 Sodium cyanide
151508 Potassium cyanide
Glycol ethers (except those specifically listed)*
1 1 0805 2-Ethoxy ethanol
1 1 1 762 Ethylene glycol monobutyl ether
108864 2-Methoxy ethanol
Lead and compounds (except those specifically listed )*
75741 Tetramethyl lead
78002 Tetraethyl lead
7439965 Manganese and compounds (except those specifically listed)*
12108133 Methylcyclopentadienyl manganese
Mercury compounds (except those specifically listed)*
1 0045940 Mercuric nitrate
748794 Mercuric chloride
62384 Phenyl mercuric acetate
Elemental Mercury
Mineral fiber compounds (except those specifically listed)*
1332214 Asbestos
Erionite
Glass wool
Rock wool
Slag wool
Nickel compounds (except those specifically listed)*
13463393 Nickel Carbonyl
1 2035722 Nickel refinery dust
Nickel subsulfide
Polycyclic organic matter-POM (except those specifically listed)*
56553 Benz(a)anthracene
50328 Benzo(a)pyrene
205992 Benzo(b)fluoranthene
57976 7,1 2-Dimethylbenz(a)anthracene
225514 Benz(c)acridine
21 801 9 Chrysene
53703 Dibenz(ah) anthracene
1 89559 1 ,2:7,8-Dibenzopyrene
1 93395 lndeno(1 ,2,3-cd)pyrene
0.00002
0.01
0.01
5
0.002
5
0.1
0.1
0.1
0.1
0.03
5
0.1
0.1
5
10
10
10
0.01
0.01
0.01
0.8
0.1
0.01
0.01
0.01
0.01
0.01
a
a
a
a
a
a
1
0.1
0.08
0.04
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
BASIS
UR
UR
UR
DEF=5
UR
DEF=5
ACUTE
CS
ACUTE
ACUTE
UR
DEF=5
ACUTE
ACUTE
DEF=5
CAP-RfC
CAP-RfC
CAP-RfC
GWP
GWP
GWP
RfC
ACUTE
GWP
GWP
GWP
GWP
GWP
-
-
-
-
-
-
DEF=1
ACUTE
UR
UR
GWP
GWP
UR
GWP
GWP
GWP
GWP
GWP
GWP
GWP
-------
0 112(g) DE MINIMIS LEVELS
CAS Chemical Name
#
684935 N-Nitroso-N-methylurea
121697 N,N-Dimethylaniline
90040 o-Anisidine
95534 oToluidine
56382 Parathion
82688 Pentachloronitrobenzene (Quintobenzene)
87865 Pentachlorophenol
108952 Phenol
75445 Phosgene
780351 2 Phosphine
7723140 Phosphorous
85449 Phthalic anhydride
1 336363 Polychlorinated biphenyls (Aroclors)
1 06503 p-Phenylenediamine
1 23386 Propionaldehyde
114261 Propoxur (Baygone)
78875 Propylene dichloride (1 ,2-Dichloropropane)
75569 Propylene oxide
91225 Quinoline
106514 Quinone
1 00425 Styrene
96093 Styrene oxide
1 271 84 Tetrachloroethylene (Perchloroethylene)
7550450 Titanium tetrachloride
1 08883 Toluene
8001 352 Toxaphene (chlorinated camphene)
7901 6 Trichloroethylene
1 21 448 Triethylamine
1 582098 Trifluralin
1 08054 Vinyl acetate
593602 Vinyl bromide (bromoethene)
7501 4 Vinyl chloride
75354 Vinylidene chloride (1,1-Dichloroethylene)
1 330207 Xylenes (isomers and mixture)
1 08383 m-Xylenes
95476 o-Xylenes
106423 p-Xylenes
CHEMICAL COMPOUND CLASSES
Arsenic and inorganic arsenic compounds
7784421 Arsine
Antimony compounds (except those specifically listed)*
1 309644 Antimony trioxide
1 345046 Antimony trisulfide
7783702 Antimony pentafluoride
28300745 Antimony potassium tartrate
Beryllium compounds (except Beryllium salts)
DE MINIMIS
LEVEL
(TONS/YR)
0.0002
1
1
4
0.1
0.3
0.7
0.1
0.1
5
0.1
5
0.009
10
5
10
1
5
0.006
5
1
1
10
0.1
10
0.01
10
10
9
1
0.6
0.2
0.4
10
10
10
10
0.005
0.005
5
1
0.1
0.1
1
0.008
BASIS
UR
CS
DEF=1
UR
ACUTE
UR
UR
CS
ACUTE
DEF=5
ACUTE
DEF=5
UR
CS
DEF=5
CAP-UR
UR
UR
UR
DEF=5
DEF=1
DEF=1
CAP-UR
ACUTE
CAP-RfC
GWP
CAP-UR
CAP-RfC
UR
DEF=1
UR
UR
UR
CS
CS
CS
CS
UR
UR
DEF=5
DEF=1
CS
ACUTE
CS
UR
-------
8
discussed in section six and Appendix B of this document. Table
1 summarizes each individual chemical or group, a proposed de
minimis rate, and the basis for each determination.
III. DOCUMENTATION OF DE MINIMIS EMISSION RATES FOR "NON-
THRESHOLD" POLLUTANTS
For the proposed subpart B rule, more than half of the
pollutants on the section 112(b) list of HAP are considered to be
"non-threshold" pollutants. This designation is based upon
available EPA and IARC (International Agency for Research on
Cancer) weight-of-evidence indicating their classification as
"known," "probable," or "possible" human carcinogens.
Documentation for the weight-of-evidence and dose-response
information for these pollutants can be obtained from the hazard
ranking technical support document accompanying the section
112(g) rule (EPA/450/3-92-010).
In Table 1 of this background document, and in the Table in
§63.44 of the proposed rule, the following descriptors are used
in the "basis" column:
~ UR
— UR-CAP
— DBF = 1
The "UR" descriptor indicates that the de minimis
emission rate was calculated based upon a risk-specific dose for
the pollutant. The risk-specific dose is the exposure level
associated with a given lifetime cancer risk, in this case, a
-------
9
risk management decision of one-per-million cancer risk. The
risk-specific dose is derived from the unit risk, an upper-bound
estimate of the excess cancer risk over background associated
with a continuous lifetime exposure to the pollutant. Readers
should be aware that there are many uncertainties associated with
inferences of population risk based upon the estimate of unit
risk.
For pollutants for which unit risk estimates were available,
de minimis emission rates were calculated in four steps.
Step 1. Calculation of the Ambient Concentration Associated
with One-per-million Cancer Risk. First, based upon the unit
risk value, the EPA calculated the concentration in the ambient
air that would yield a lifetime cancer risk of one-per-million.
Using benzene as an example, lifetime continuous exposure to 1
microgram per cubic meter of benzene is associated with a risk
which may be as high as 8.3 in one million, with a lifetime risk
of one-per-million being equivalent to 0.12 micrograms per cubic
meter (one divided by 8.3). As a risk management decision for
the subpart B rule, unit risk estimates supported the calculation
of de minimis levels under the assumption that a 70 kg human
breathes 20 cubic meters of air daily.
In some cases, when inhalation unit risk values were not
available, estimates for oral exposures, expressed in units of
(mg/kg/day),-1 were used. There are uncertainties associated
with the use of data from the oral route to make inferences about
inhalation route of exposure. On one hand, the use of the risk
-------
10
associated with oral exposure to a HAP may be overly conservative
in estimating a risk-specific dose for inhalation exposure. Such
cases would occur, for example, when significant first pass
effects and activating metabolism are important to the observed
toxicologic effect. On the other hand, risks associated with
inhalation-related portal-of-entry effects may be underestimated
when based on information from oral exposure. A discussion of
extrapolation of oral to inhalation values and the attendant
uncertainties using such data may be found in the hazard ranking
technical support document (EPA/450/3-92-010).
Documentation of each unit risk estimate used in the
establishment of de minimis values for the subpart B rule can be
found in Table 2. Additionally some HAP only had carcinogenic
potency factors other than a unit risk available (Effective Doses
for 10 percent response over background, ED10). The EPA derived
unit risk estimates for such pollutants from the ED10. These
estimates appear in Table 3 and are supported by a technical
support document which can be found in the Docket for the
proposed rule (EPA/600/R-93/199, Slope Factor Estimates For
Several Hazardous Air Pollutants).
Step 2. Adjustment of risk-specific dose for duration of
exposure. The second step in the calculation was to adjust the
risk-specific dose to account for the expected maximum exposure
period that could elapse before a major source would be subject
to maximum achievable control technology (MACT) emission
limitation under section 112(d) or section 112(j) of the Act.
-------
iUa
5555§ii!
OJ
rH
.0
tS
H
8 l\
5hf
t _
H
*S?
T «!"
=-eo toiaia
SicrcZtrS '
S
£
ci ™
•» S • • • V8 •? < • • 8ft!c • 2 kJckS
ION p) W tfi ^ W W OT
' UJ UJ ' ' * ' ' ' ' UJ * UJ ' UJ ' Ul UJ UJ UJ
«w o» cw CM en CM »- »-
K" & $ e?
o w co Q £-<2 Q Q g, O •— OOJ^|« • tO, . . i i .h»( •m'*"1 •
$«??? 5
^ in m CM CM
• w
99
UJ UI
9
UJ
in in v
999
JiTJ
IS
o
.
• m o m
CM
'CD
9 9 So
UJ UJ
n . CD . , o r*.
*- (O CO U)
5?
LfJ UJ
U> ^ »*• *"
i
i w o
Sfy
r-
_ssa;
a n in n r
••>.£
iLpii
" 8-5 S S 5 *
8J!rt3
!**.
|||
? I S " l-s.
liii^l
ifi (S m m i ffl^^^
fl
• »- r> CM m h» f^-
-------
lOb
tOOOOOOO'-'-t
m "- i- •- •- o
2 b 6 *" 6 6 6
o
«-t-«-«-*-«-O*-IO^O
osgwin«-«-w*-O'-oj»-owO'-a>o
** P «" P ^" a ^O'~OQT~
d d1
eoo'-iow«-O'
_ x . . qo00 oo-<
00 00 '
99? 9 9
s«y s a
99
n , . i *«
9 99
B 88
o> , n CD ,
9 99 999 9999 9
ffi Wffi SSS SSffiS $
'
«eo
COCO CO UJ CO
trier ' ' * ' ' i>.inr^
S B » K
co K rv r^
— « r-
-------
10 c
It U
^(o^
ioi:
5 <
ui(C
.n ,- .- I uj U - I U -
i?iI'ii'.fc;'?5.trSiI
;co w
i O O
g
ooobo o
^ ,-; ^ O ^ ^
\%'>
job
8!
9 89
UJ UJ UJ
uiu/
5 9? $
^ n CM
!!!
^
n
li)
a
UJ ' '
n oj
LUUJ
9
UJ
n •- en
co I
' £ :
1
5
i
UJ
S
CO
1 • • eg '
co Q
~ °
Q JI-CO
§ ffiS
CO
1 ' ' I ' '
'7f °-
• 5 uj
'
Q
J
cr §
§
CO
cr
S.£c
UJ UJ C
UJ UJ
11
ill?
?
UJ
o
UJ
9 99
CM CM »-
8
LU
SS 5
ss.«
9
ui
?
UJ
s?
UJ
9 38 SSS
UJ UJ UJ UJ UJ UJ
tn pj ^^ n co m
tn
9
UJ
n
9
UJ
in
9?
UJ UJ
*. CO
9
UJ
CM
^> (O
99
UJ UJ
9
UJ
en
0
UJ
CM
UJ<0
; m CM , CD c« .
(
• u o S < o
<«2o . ,
.00
CC ff
s-
UJ
CO CD CO ^ ^
. = rf .=QQ-
1 CO 5 UJ UJ _
UJ UJ UJ
0
I
-------
lOd
(0 (
Ol
55!
§§'
00
'§§°5'°§'
si00 §
ggg«*c*ggggg
joooppopoooo
bbbbdbbbooo
<7
$
9999 9
9
to
??
UJ
CO O 0) (0 CO
w
ir
CO
£
CO
IT
CO CO CO
EE • • 2
9999 9
99
Ol CD W W r-
9
UJ
uico
IS
o
Ul
JO
) QC
»•" m >"
E ' ' ffi ' ' ' OC
CO Q CO CO CO
CO
£
CO
cr
SOS252 cococo
trice 'iccir
I
M
Z
s
CM
><*
o a
*- r-
-------
lOe
g i-i
If*
o —
U-
LU
-------
lOf
Table 3. Summary of Qt* and de minimis emission rates derived
from ED,as.
10*
CAS #
75558
1120714
119904
121142
101144
-
79447
51796
151564
75218
684935
95534
53963
79469
HAP
1,2, propylene imine
1,3, propane sultone
3 , 3-dimethoxy-
benzidine
2 , 4-dinitrotoluene
4,4' -methylene
bis ( 2-chloraniline )
beryllium salt
dimethylcarbamyl
chloride
ethyl carbamate
ethylene imine
ethylene oxide
N-nitroso-N-methyl
urea
o-toluidine
2-
acetylaminof luorine
2 -nitropropane
qi*
(mg/kg/day)-1
2.3E+1
3 . 9E+0
5.2E-1
3.7E-1
3.0E-1
8.1E-1
(microg/m3)
1.1E-3
(microg/m3)
9.1E-2
2.5E+1
2.3E-5
(microg/m3)
3.5E+2
2.0E-2
9.4E-1
-
De minimi s
emission
rates for
section
112(g)
(tons/yr)
0.003
0.03
0.1
0.02
0.2
0.00002
0.02
0.8
0.003
0.1
0.0002
3
0.005
DBF = 1
** Common
inhalation
unit risk
(micrograms
/m3)-1
6.7E-3
7.8E-4
1.5E-4
1.1E-4
8.7E-5
8.1E-1
1.1E-3
2.6E-5
7.3E-3
2.3E-5
l.OE-1
5.8E-6
3.9E-3
-
** The expression of the q1*
risk is intended for ease of
rates and does not reflect a
oral exposure for these HAP.
in terms of common inhalation unit
calculation of de minimis emission
derivation of inhalation risk from
-------
11
The EPA selected a 7-year period as the duration of
exposure, rather than the more frequently used 70-year lifetime
exposure. The 7-year period was selected because sources who
are subject to modification requirements under section 112(g)
would be required to achieve a MACT emission rate within 7 years
under sections 112(j) or 112(d). The EPA is required to
promulgate MACT standards in accordance with a schedule in
section 112(d) of the Act by November 15, 2000. Such standards
would require compliance for existing sources by no later than
the year 2003. Furthermore, if the EPA does not meet the
deadlines in its schedule for promulgation section 112(d)
emission standards, States are required under section 112(j) to
develop equivalent emission standards within 18 months after the
EPA fails to meets a deadline for promulgation of a MACT
standard. As a result, the longest time for which standards
would not be developed is 18 months after November 15, 2000, i.e.
May 2002. Because the section 112(g) program will start up in
most states in early 1995, it is judged that 2002 minus 1995, or
about 7 years, is a reasonable estimate of the time that would
elapse before imposition of technology requirements for emission
increases which have been subject to the modification
requirements of section 112(g).
Adjusting for this 7-year exposure period and using benzene
as the example, a lifetime cancer risk of one-per-million is
equivalent to (70/7) times 0.12 micrograms per cubic meter, or
1.2 micrograms per cubic meter.
-------
12
For any known, probable, or possible human carcinogen for
which a unit risk estimate is available, the risk-specific dose
used for the calculation of de minimis can be calculated as
follows:
Risk-Specific dose ((ig/m3) = EA X (1 X lO'6) / UR
where,
EA = exposure adjustment = 70/7 = 10
UR = Unit risk value, (ng/m3)'1
Step 3. Development of Standard Dispersion Assumptions.
Emissions increases of HAP from a given release point, when
dispersed in the atmosphere, will cause increases in ambient air
concentration of those HAP according to the following equation:
Concentration increase, x (ng/m3 ) = Q X x/Q
where,
Q = increase in the emission rate (typically tons/yr)
x/Q = a multiplier indicating the amount of dispersion
between the release point at a specified downwind
location (i.e., the amount ^ig/m3 added to the
atmosphere for every tons/yr increased).
As discussed above, for purposes of proposed subpart B, the
EPA decide to express the de minimis values as emission rates
rather than concentrations. As a result, it became necessary to
develop a standard x/Q value that could be used. Development of
this value required (a) development of a "model plant" that could
be used to characterize reasonable conditions for the purposes of
establishing de minimis values, and (b) performing dispersion
-------
13
calculations using this model plant under a number of different
sets of weather conditions.
The following set of assumptions were made for the model
plant:
Worst case down-wash is assumed
Stack Height = 10 meters
Stack Diameter = 1 meter
Exit Velocity = 0.1 meters / second
Stack Temperature = 295 degrees Kelvin (ambient)
Distance to Nearest exposed individual = 200 meters
For this model plant, the EPA performed dispersion
calculations using the EPA's Human Exposure Model for 314 sets of
meteorological data. Each of these calculations is provided in
Appendix A. The results of these calculations, which are
identical to those used by the EPA for identification of high-
risk pollutants in accordance with section 112(i)(5) of the Act,
are contained in Appendix A. The results indicate that, using
the median meteorological data, for each 5.02 micrograms per
cubic meter of a pollutant added to the atmosphere at the assumed
fence-line of 200 meters, there would be 10 tons of emissions.
This ratio, which is equivalent to 2 tons/yr per every 1 jig/m3 at
the fence-line, was used as the standard relationship between the
annual emission rate of any HAP and the ambient concentration at
the fence-line for the purposes of setting de minimis emission
rates for the proposed subpart B rule.
-------
14
The EPA believes that the assumptions used for this
dispersion analysis represent a reasonably conservative
dispersion scenario for sources of HAP emissions. It is
recognized that there are conditions that would result in less
dispersion, and that the dispersion analysis does not represent
an absolute worst-case. For example, higher ambient air
concentrations could be experienced for (1) releases for which
weather conditions represent the worst-case of the 314 stations,
rather than the median of the 314 stations (2) releases at ground
level, rather than the assumed 10 meters, and (3) releases
immediately adjacent to residences, which could occur at
distances less than the assumed 200 meters. The results
displayed in Appendix A show that the highest concentration
experienced at any one of the 314 stations was 15.6 ng/m3, while
the lowest concentration was 2.22 ng/m3. The median value,
therefore, could under-predict by a factor of approximately 3, or
could over-predict by a factor of approximately 2. The EPA also
analyzed the sensitivity of the ratio of annual emission rate to
ambient fence-line concentration with regard to stack height and
distance to nearest receptor. The results of this sensitivity
analysis are shown in Table 4. Stack release parameters for the
conditions cited in Table 4 are identical to those listed for the
standard x/Q value. The results indicate that, for any given 10
tons/year release, the resulting concentration could be
significantly higher than, or significantly lower, than that
resulting from the selected model plant.
-------
15
Table 4. Sensitivity of ambient fence-line concentration to
stack height and fence-line distance for the "Model" Plant
Stack height
(meters)
1
3
3
10
10
10
15
50
100
Distance to nearest
residence (meters)
200
100
500
100
200
500
200
200
200
Median
concentration
(Hg/m3)
16
34
3.4
6.7
5.0 *
2.8
2.5
0.15
0.026
* These parameters are assumed in the model plant used to
calculate emission rates for the proposed rule
-------
16
The EPA believes that if de minimis emission rates were
based upon absolute worst-case conditions, the number of
modifications subject to review would greatly increase, and that
a case-by-case dispersion assessment would probably be needed in
all cases to ensure that truly de minimis emission rates were not
regulated. The EPA does not believe that the increased scope and
complexity of the program are warranted.
Step 4. Calculation of De Minimis Emission Rate. As a
fourth step, the EPA used the risk-specific dose at a one-per-
million risk, identified in Step 2 above, in tandem with the
standard emission rate/concentration relationship developed in
Step 3, to calculate a de minimis emission rate. For example,
Step 2 indicated an exposure associated with one-per-million risk
of 1.2 ng/m3 over the 7-year exposure period for benzene. In
order to reach this exposure level, the model plant would need to
emit 1.2 X 2, or 2.4 tons per year of benzene. For purposes of
the proposed rule, each of the values is rounded to one
significant figure; for benzene, 2.4 tons per year is rounded to
2 tons per year. The EPA believes that one significant figure is
appropriate, given the uncertainties in the unit risk values and
exposure assumptions on which the values are based.
The "UR-CAP" description in Table 1 indicates that applying
the information on the risk-specific dose in tandem with the
standard emission rate/concentration relationship yielded an
-------
17
emissions rate greater than 10 tons per year. As indicated
previously, a risk management decision was made to "cap" de
minimis values at 10 tons per year.
The "DEF=1" descriptor indicates that the pollutant was
assigned a default value of 1 ton/yr. This default value was
assigned for "non-threshold" pollutants for which no unit risk
value was available. The choice of 1 ton/yr is a policy decision
based upon a review of the de minimis values for pollutants with
potency values. The EPA does not believe that these pollutants
should be assigned the 10 tons/year cap. An assumption is made
that if potency values were available for such pollutants, they
would be consistent with the distribution of de minimis values of
pollutants with adequate dose-response information, and the value
would likely be less than 10 tons per year.
IV. DOCUMENTATION OF DE MINIMIS EMISSION RATES FOR "THRESHOLD"
HEALTH ENDPOINTS
In addition to the considerations for "non-threshold"
pollutants discussed above, de minimis values were assigned for
"threshold" health endpoints based upon concentration benchmarks
representing "an ample margin of safety." For purposes of the
proposed rule, the EPA has made a policy determination that the
Inhalation Reference Concentration (RfC) represents an "ample
margin of safety" for non-cancer effects from long term
inhalation exposures.
-------
18
For pollutants in which an RfC has been verified by the EPA
and is listed on the Integrated Risk Information System (IRIS)
data base, the de minimis emission rate was determined using the
following equation:
Qd, = 1000 X RfC / (x/Q)
where:
RfC = EPA's reference concentration (mg/m3)
x/Q = relationship between emission rate (Q) and annual
average concentration (x) for the maximum exposed
individual, (micrograms per cubic meter per tons per
year), 2 tons/yr per 1 ng/m3
1000 = conversion from mg/m3 to [xg/m3
This equation uses the same "model plant" and standard
dispersion assumptions discussed previously for "non-threshold
pollutants." However, the equation does not adjust for the 7-
year exposure period. The RfC is designed to protect against
chronic exposure for a lifetime. It is inappropriate to adjust
exposure duration for a less than lifetime exposure and use the
RfC as a health safety benchmark. Each RfC used for the proposed
rule is indicated in Table 2.
For those pollutants with no available verified RfC, a
series of default values were used to establish de minimis
emission rates. The descriptor "CS" in Table 1 indicates that a
Composite Score was used as the basis for a de minimis emission
rate. A complete description of Composite Scores, and
documentation of the Composite Scores assigned each pollutant
-------
19
with the "CS" designation, can be found in the hazard ranking
technical support document (EPA 450/3-92-010). Where a composite
score (but no RfC) was available for a given pollutant, the
default assumptions were used to assign de minimis emission rates
as follows:
Range of Composite Score
CS = 1 to 20
CS = 21 - 40
CS > 41
De minimis Emission Rate
10 tons /year
1 ton/year
0.1 tons /year
The selection of composite score ranges for default de
minimis emission rate categories were similar to the ranges used
for setting Reportable Quantities under Section 102 of the
Comprehensive Environmental Response, Compensation and Liability
Act (CERCLA). The above ranges coincide, respectively, with
Reportable Quantities of 10, 100, and 1000 Ibs. In absence of
RfCs for de minimis determinations, the EPA believes that the
CERCLA program provides a reasonable basis for the overall
magnitude of the difference in de minimis values for section
112(g). However, the assignment of the emission rate for each
default category based on Composite Score is a policy-based
decision.
-------
20
The descriptor PSD indicates the use of a de minimis value
also used in the prevention of significant deterioration program
(40 CFR 52.21). The EPA believes that it is appropriate to
consider these values when available, because the section 112(g)
and PSD program have similar goals in establishing "trivial"
levels below which pollutants are not subject to regulation.
The descriptor "Def =5" indicates that the HAP does not
have an RfC, does not have a composite score, has not been
assigned a de minimis value under the PSD program, is not
classified according to EPA or IARC as a known, probable, or
possible carcinogen, and is not classified as a "high-concern"
pollutant under the hazard ranking. For such pollutants, a
default value of 5 tons per year was assigned. This value is
greater than the 1 ton per year value assigned to potential
carcinogens with no potency estimate but less than the 10 ton
cap. The EPA believes that the assignment of this default de
minimis emission rate is a reasonable risk management decision
considering the values assigned other HAP.
The descriptor "ACUTE" indicates that a risk management
decision was made to assign an annual de minimis emission rate
based on concern for toxicity from short-term exposures.
Identification of such pollutants of concern for short-term
toxicity, based upon "levels of concern" used for section 302 of
SARA, Title III, is documented in the hazard ranking technical
support document (EPA/450-3-92-010). For these pollutants, a
default annual de minimis emission rate of 0.1 tons per year is
-------
21
proposed. This de minimis value coincides with the default value
assigned to pollutants of highest concern for chronic non-cancer
effects.
Some HAP may produce a spectrum of health effects including
cancer and non-cancer effects from long or short-term exposures.
De minimis values for pollutants having multiple health concerns
are proposed to be set at the lowest identified value. For
example, a "non-threshold" pollutant with a de minimis emission
rate of 0.1 tons/yr based on concern for short-term exposure, and
a de minimis emission rate of 1 ton/yr based on a cancer risk of
one-per-million, will be assigned a de minimis emission rate for
purposes of the proposed rule of 0.1 tons/yr. Similarly, for
pollutants for which concern for chronic exposures, based upon
the RfC, yielded a value less than that for a one-per-million
cancer risk, the de minimis emission rate for the proposed rule
is based upon the RfC.
The EPA has asked for public comment in the proposed section
112(g) rule on an interim "default" methodology to assign short-
term Ib/hr de minimis emission rates for pollutants of concern
for short-term exposures. Ideally, the EPA would prefer to
develop hourly de minimis emission rates for acute exposure on
health criteria for short-term exposure. In the future, the EPA
may consider revising the de minimis emission rate table when
appropriate short-term RfCs or some other appropriate health
safety benchmarks are developed.
-------
22
The EPA considered the following approach as an interim
method to establish short-term de minimis values based upon
Levels of Concern (LOCs). LOCs have been established for
chemicals on the Superfund Amendments and Reauthorization Act
(SARA) Title III section 302 list of "extremely hazardous
substances." The LOCs indicate levels of airborne concentrations
of chemicals for which no serious irreversible health effects
occur following a short term exposure (30 minutes). LOCs are by
definition one-tenth of "immediately Dangerous to Life and
Health" levels (IDLHs) produced by NIOSH.
The EPA believes that LOCs have some possible merit for use
in setting short-term de minimis values. LOCs are the only
values used by the EPA which have an extensive data-base and are
designed to protect from serious effects of short-term or acute
exposures. LOCs are intended to protect the general population
including sensitive individuals.
However, there are several disadvantages for using LOCs to
set de minimis levels for such acutely toxic HAP. First, most of
the LOG values are based upon animal LC50, LD50, LCLO, and LDLO
data which may not protect against all health effects in humans.
Second, the safety factor of 10 which is applied to IDLHs to
protect sensitive individuals of the population and for
protection against serious health effects may not be adequate.
There are questions concerning the scientific peer review of the
rationale for each LOG and supporting data. Finally, it is not
known what the maximum duration of exposure at the LOG would be
-------
23
for protection against adverse effects. Despite these serious
disadvantages, LOCs may be appropriate as an interim basis for
setting short-term de minimis levels for acutely toxic pollutants
in the absence of a better methodology and supporting data.
The methodology is as follows. First, for each pollutant of
concern for acute exposures, a short-term de minimis
concentration for each pollutant would be derived by dividing its
LOG by a safety factor of 1000. This factor of 1000 is a crude
estimate of the factor needed to convert the LOG, which is based
upon mortality or very severe effects, into a level that would
ensure that no adverse health effects would be observed. It is a
risk management decision. Second a "reasonable worst case" model
plant, similar to that described above for de minimis
determinations for long-term exposure, is developed to describe
the relationship between the de minimis concentration and a de
minimis emission rate. Again, those model plant parameters are:
Stack height is 10 meters;
Exit gas velocity is negligible;
Stack diameter is 1 meter;
Exit gas temperature is equal to the ambient temperature;
Worst-case down-wash is assumed;
The nearest exposed individual is at a distance of 200
meters
For this model plant, the "Tier 1 screening approach"
described in A Tiered Modeling Approach for Assessing the Risks
Due to Hazardous Air Pollutants (EPA-450/4-92-01), is used to
-------
24
describe the relationship between the de minimis concentration
and a pound/hour de minimis emission rate. Use of this approach
results in a ratio of maximum off-site short-term concentration
to emission rate of 314 (micrograms/m3)/(lb/hr) or 0.314
(milligrams/m3)/(lb/hr). This factor indicates that the
prototypical facility which emits 1 Ib of pollutant in an hour
will have a maximum short-term concentration off-site which will
equal to 0.314 milligrams/m3.
The short-term concentration predictions made using the Tier
1 method are interpreted as 1-hour average concentrations, i.e.,
they account for the dilution due to the general meander of a
dispersed plume over the course of a 1-hour period. Since the de
minimis concentration values relate to "peak" or very short-term
exposure levels (maybe on the order of a few seconds), the EPA
believes it would be desirable to derive peak concentration
values from the 1-hour predictions. Data taken by the EPA
indicate that the concentration levels during any few second time
interval within the 1-hour period will not vary more than a
factor of two. Therefore, for purposes of the examples described
below, a "peak-to-mean" ratio of two was used, that is, the peak
concentration is assumed to be twice that of the 1-hour average.
Using the value, [(0.314 milligrams/m3)/(Ib/hr)], coupled
with the peak-to mean ratio of two, the de minimis emission rate
(Ed,,,, from the ambient de minimis concentration level (C^) for
each acutely toxic pollutant would be calculated as follows:
Ed» = [Cdn/(2)]/0.314
-------
25
The following Table lists a number of examples illustrating
the LOCs and the short-term de minimis emission rates that would
result based upon this method. The EPA has asked for comment in
the proposed rule on whether the final rule should incorporate
these values, and on other possible alternative methods that
could be used to derive short-term de minimis emission rates.
Table 5. Examples of possible short-term de minimis emission
rates
CAS #
107028
7783702
1303282
1377533
7784421
94077
100447
57578
1366190
7782505
79118
107302
10025737
10210681
77781
534521
151564
Pollutant
Acrolein
Antimony pentafluoride
Arsenic pentoxide
Arsenic oxide
Arsine
Benzotrichloride
Benzyl chloride
beta-Propiolactone
Cadmium oxide
Chlorine
Chloroacetic acid
Chloromethyl methyl ether
Chromic Chloride
Cobalt carbonyl
Dimethyl sulfate
4,6-Dinitro-O-cresol and salts
Ethyleneimine
LOG
(mg/m3)
1.15
2.70
8.00
1.40
1.90
0.700
5.18
1.50
4.00
7.25
1.80
1.82
0.0500
0.270
5.00
0.500
4.00
Short-
term de
minimis
value
(Ibs/hr)
0.00183
0.00430
0.0127
0.00223
0.00302
0.00111
0.00824
0.00239
0.00637
0.0115
0.00286
0.00290
0.0000795
0.000430
0.00800
0.000800
0.00636
-------
26
75218
62207765
77474
7664393
7783075
12108133
60344
624839
13463393
56382
75445
7723140
151508
143339
13410010
10102188
78002
75741
7550450
584849
Ethylene oxide
Fluomine
Hexachlorocyc lopentadiene
Hydrogen fluoride
Hydrogen selenide
Methylcyclopentadienyl-
manganese
Methyl hydrazine
Methyl isocyanate
Nickel carbonyl
Parathion
Phosgene
Phosphorous
Potassium cyanide
Sodium cyanide
Sodium selenate
Sodium selenite
Tetraethyllead
Tetramethyllead
Titanium tetrachloride
Toluene diisocyanate
0.3ppm
3.00
0.0195
1.64
0.660
0.600
0.940
4.70
0.350
2.00
0.800
3.00
5.00
5.00
1.60
2.30
4.00
4.00
1.00
7.00
—
0.00477
0.0000310
0.00261
0.00105
0.000955
0.00150
0.00748
0.000557
0.00318
0.00127
0.00477
0.00796
0.00796
0.00255
0.00366
0.00637
0.00637
0.00159
0.0111
-------
27
V. CONSIDERATIONS FOR POLLUTANTS OF CONCERN UNDER EPA's 112(m)
GREAT WATERS PROGRAM.
The descriptor "GWP" in the table of de minimis values
indicates that a value of 0.01 tons per year was assigned to a
"Great Waters Pollutant" for which a special de minimis value was
determined as a policy decision. The EPA believes that de
minimis values under section 112(g) can take into account a
hazardous air pollutant's potential for causing non-air quality
health and environmental impacts. For example, deposited
pollutants which are persistent and bioaccumulate are of possible
concern to the living resources in the ecosystem into which they
are deposited. The EPA is required by section 112(m) of the Act
to investigate the potential for adverse impacts of atmospheric
deposition to the Great Lakes, Chesapeake Bay, Lake Champlain and
Coastal Waters (collectively called the "Great Waters"). In
carrying out these requirements, the following 13 HAP appear to
be of the greatest concern for bioaccumulation and
bioconcentration: lead and lead compounds, POM,
hexachlorobenzene, mercury, PCBs, chlorinated dioxins,
chlorinated furans, toxaphene, chlordane, DDE, DDT, lindane, a-
hexachlorcyclohexane, and cadmium. Ref: Swain et al. Exposure
and Effects of Airborne Contamination for the Great Waters
Program Report. December 22, 1992.
For these pollutants, the EPA does not believe that methods
are currently available to quantify the relationship between
emission rates and exposures for these pollutants. Accordingly,
-------
28
the EPA does not believe that a quantitative method for
developing de minimis values for such HAP yet exists. The EPA
believes, however, that it would be reasonable from a policy
standpoint to assign relatively low values to these pollutants to
address concerns for their potential to concentrate and cause
adverse effects to the "Great Waters".
For the proposed rule, a policy-based "cap" of 0.01 tons per
year was used as a de minimis value for such pollutants. This
value represents 10 percent of the lowest de minimis value
assigned to HAP based upon chronic toxicity (i.e., 10 percent of
the value assigned to pollutants with a composite score greater
than 40). If the de minimis value for such pollutants was based
upon other considerations (described above) and yielded a value
greater than 0.01 tons per year, the 0.01 tons per cap based on
"Great Waters" consideration was assigned. For example,
depending on the specific mercury compound involved, the health-
based and default criteria yielded values of 0.1, 0.6, and 5 tons
per year. For each of these mercury compounds, the proposed rule
lowers the value by assigning the 0.01 tons per year "cap." On
the other hand, the value for dioxin was already well below 0.01
tons per year, so the 0.01 tons per year "cap" was not the
limiting consideration.
Other policy approaches were considered. One approach would
be to select an alternative "cap" such as 0.1 tons per year.
Another possible approach might be to lower the de minimis values
to one-tenth that of the default or health-based values. For
-------
29
example, under this approach elemental mercury would have a de
minimi3 emission rate of 0.06 tons per year rather than the value
which would have been assigned it based on PSD criteria.
VI. SPECIAL CASE OF RADIONUCLIDES AND FINE MINERAL FIBERS
(UNRANKABLE)
The chemical group "radionuclides" comprises a large number
of different radionuclides and requires special treatment in the
context of assigning appropriate de minimis values for the
purposes of section 112(g). The EPA is relying on previous
efforts by the Agency to evaluate cancer risks from radionuclide
exposure and to provide a subcategorization of the different
members of the grouping. For radionuclides, the EPA believes
that an effective dose equivalent of 0.3 millirem per year for a
7 year exposure period would result in a cancer risk consistent
with the one-per-million criteria used for other "non-threshold"
HAP. Accordingly, this 0.3 millirem level serves as the basis
for a de minimis level for section 112(g). Techniques for
evaluating the level of radionuclide emissions that would result
in a 0.3 millirem dose are contained in subpart B and I, and
Appendix E of 40 CFR part 61.
Fine mineral fibers, as a group, also require special
attention in setting de minimis levels under the proposed rule.
The fine mineral group contains members which have been
determined by the EPA or IARC to be at least possible human
carcinogens and such pollutants are cited in Appendix B of this
-------
30
document as well as the data concerning these HAP. Because size,
shape, as well as chemical composition of the fibers are
determinants of the toxicity of these fibers, they can not be
ranked with the other "non-threshold" HAP. The same
considerations make determining an appropriate de minimis levels
for this grouping difficult. Therefore, the EPA will have to
make a policy-based decision on what de minimis levels for this
grouping will be for section 112(g) and is asking for public
comment on what those levels should be in the promulgated rule.
The default level is proposed to be an emission rate of zero.
Although asbestos is listed separately in the Act, it is also to
be treated like the fine mineral fibers grouping and data
concerning its carcinogenicity is listed in Appendix B of this
document.
VII. CASE BY CASE DE MINIMIS DETERMINATIONS
As discussed previously, the proposed rule provides for
State reviewing authorities to use ambient benchmarks to develop
case-by-case determination of de minimis emission rates. In this
fashion, the particular dispersion characteristics of the source
of the emission increase can be taken into account. However, the
one in a million risk of cancer or ample margin of safety
criteria for noncarcinogens reflected in the allowable fence-line
ambient concentrations of HAP may not be altered. States may
submit for approval the methodology for such case-by-case
determinations. These programs must be reviewed by the EPA in
-------
31
accordance with section 112(1) of the Act, and regulations
proposed as subpart E to 40 CFR Part 63.
-------
Appendix A.
Dispersion Calculations for the Model Plant
-------
33
The following table indicates the results of 314 dispersion
calculations using EFA's human exposure model (HEM). The following
set of assumptions were used as input data for these calculations:
Worst case down-wash
Stack Height = 10 meters
Stack Diameter = 1 meter
Exit Velocity = 0.1 meters / second
Stack Temperature = 295 degrees Kelvin (ambient)
Distance to Nearest exposed individual = 200 meters
For purposes of de minimis values for the section 112(g)
program, only the first and last columns in these tables are
relevant. The last column (the column to the far right) indicates
the meteorological station number. The first column (the column to
the far left) indicates the resulting annual average concentration
for the model plant for a given set of meteorological conditions,
expressed in micrograms per cubic meter.
-------
3
e
33a
« e
3
a
oooaoooaooaoooaeoaooaoaoaooaaooaoooo
e •
••
Z O«O«OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
U I I I I I I f I I > I r I I I I I I I i I I I I i i i i I I i i i i i i i I i i i i i i i
C UMMWWWUWUUWUUWUUUUUUMIilUUUUUUUUUIJUUUhlblUWUUUUUU
I I
••••••MOOOOOOOOOOOOOQOQOOOOOOQOOOOOOOOOOOOOOOO
oooooooQooooooooooooooooooooQQOQOQOQooooooe
UUUUUUUUUUUMWhJUIWMUUUUUUUUUUUUUfatUUUUUUUUI
• a oa«eooaoeooooaaooaooooooooaoooooooooooooooooo
- • «»»»*»*»••-•»•»»»»»•*«»•»• «•••»••••»»»*»»•«.»»
*> 'W UMMMMUUMUUUUUhlUUUUUWWWIilUUUUUUUUUUUUfalUlUUUUUUUW
• ^< n«^^ma'^>^vv»o>>^_>x«9^\a«^p<><>ioiM>«ln>«o««i»9ir^>«ioi/^in-«<^><«nO'*«»»*»1^^>'N — '^-"<»>»>«>^r^r>«o»«^i/1>«in»«»— •^O««'N»ir-v««fi«ni/i — i^«^or~,
S tt
U
•
0 »* ^* ^ O^ 0* ^^ 0* ^ tf* ^ ^ ^ ff* 9 0* 0* 0* O^ 9^ 0^ 0^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ fl^ ^^ ^K 0^ 0* 0^ 0t 0% 0* 0^ ^ 9* tf* 0t
0
• 0,
— — — — — — ooooooooooooooooooooooooooooooooooooooo
,. •ooooooooosoeoooooooooooooopoooooooopooooooooo
_ — — ^•^••^•^^^•— —•—-^»^^^OBO*««H»M1HPOBOB^OB^^>— *~^^«H •• tJVHfHffMIHIIiaiMfBiw^U
UUUWUUUWUWU«JWWUUUUWUUU1UUUoJUWUWUUUUUWUbl«lbJUUU9
*^ ^^ ^* ** ** ^9 Ml ^* ^ ^ ™* ^* ^ O O 0k ttV ^* ^B irt t»ft ^^ ^^ *^ <^t ^* *•* "* *•* 0* 0* 0% TB) 0^ 1^ f* f"* ^B ^B ^B ^B ^O **^ '
*** ** ^* ** ** ** ^^ ^* ^ ^ ^ 0* 0* 9 0t ^B 0^ 4B* 0J 04 04 4V) ^B) 04 04 04 04 0^ ^V ^* ^* ^* j^ ^* f* ^* P** f* f* f* f^
43
^ s
•U U
O IU
-------
33b
9
e
«• ^* ^* %A ^V ^B ^P ^B irt irt ^9 ^tf ^^ ^tf •* ^A ^* ^A MB ^* ^A ^M ^R ^^ ^t 1B ift irt tA ^A *V ^A 9 ^t ^* ^A ^^ ^V ^A ^^ 1^ 1^ ^* ^* ^*
« > oooaoooaoooooooooooooooooooooooooooooooooooo
&• oooooooooooooooooeoooooooooooooooooooooooooo
B e
U
— e
3 9
e •«
eg ooooooooooooo«oooooooo«t««oooooooonooooooo* > o r>
a ""*"""*•" """
oooooooooooooooooooooooooooooooooooooooooooo
• ooooooooooooooooaooooooooooooooooooooooooooo
ooooaaaoooooooooooooooooooooaooooooooooooooo
& *• 40 49 40 ^A *• ^A ^0 ^0 ^0 f ^ ^ ^O ^ ^A ^O ^B %0 *0 ^ ^ ^ ^ %O %O ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ %tf ^ ^ vO
e •
a.
r oooooooooooooooooooooooooooooaoooooooooooooo
^ I I I I I I I I I I t I I I « If I I I I I I I I I ) , ! . , I I ) I .1 II
C UMUUWMUhlUWMUWWWUWUUMUMUUUUMUUMUUUWMUU^UIUUUUU
I ••
^* ^w •• ^* f* ^* ^^ ^t «^ ^* ^P •* ^B ^P ^* ^fc ^fc %^ •* *0 ^^ 4A fcrt ^P *• ^* •* ^i ^* *• O* ^* ^P ^* •• •* ^B ^* *^ ^** ^^ ^P ** ^^
jt oooooooooooooooooaoooooooooooooooeeoooooooeo
il OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
K UUUWblUUIWUUUUUlUUUUWUkiWWWblUlUUUUUUULJUUUWUUJUlULJUUI
« ™T ...
• U •••••^.•-•-•-•-••• — ^-••• — — — -«-»-«^.««..«.— .— ,«...,.•«, ^.._«..«—.»«^ — — .— — —
• e ooooooooooooooooooooooooooooooooooooooooeooo
W T> UMhlWUUUUUUUWUUUUUUUUUIUUUUlUUUUUUUUUUUUUUUlUWULJ
- e ....
i •• oooooooooooooooooooooooooooooooooooooaaaoooo
E
ooooooooocoaooooooooeooooooooooooooooooooooo
• aoeoooooosaeoaoceeooooooooooaaaaaeeooaoooooo
e
o
•c
o
c
c
-------
33c
• > ooeooooooooooooooooeoooooooeeoeoeoo
J, J 000000*0000000000000000000000000000
• +»
ct e
•
u
— e
« •
3 ^
c u ooo««oooooomoooooooo«>oooooooov«or»ooo
^ g ^o^^o^***ov««^M^«0^«in^inin*«r*iAiA^toor«^^^Q^ot4vin^«»*'iA^^r^«0«4^4a^
P4 «• •• VN ^W ^^ ^* •• ^* ^* *^ ^* *• ^* ••• ^* ^* ^* •* ^* ^* ^^ ^* •* ^* ^* ^* ^* ^* ^* *• ^* ^* ^* ^* ^* ^* ^*
* OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
, 3 ^*»»»»^»»»»»»»»»»»«»»»*»»»»»»»»»»»»»»»»»»«»»»
n ^y ^t *^ *^ ^^ ^* ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ** '^ ^^ ^* ^^ ^^ ^^ *^ ^9 ^^ ^^ *^ ^s ^^ *^ ^* ^^ ^^ ^^ ^^ ^9 ^^ 4s ^B ^9 ^& ^i ^s ^^ ^* ^* ^*
•
3
ooooooooooooooooooooooooooooooooooooooooooooo
• ooooooooooooooooooooooooooooooooooooooooooooo
ooooooooooooooooooooooooooooooooooooooooooooo
«
e •
f*
oooooeoooooooooooooooooooooooooooooeooooooooo
^ t|iitiiiitiiiii(iiitiiiitii
C ^1 ^A ^J ^A ^J ^A hi hi hi hi ^4 hi hi hi U hi hi hi ^J ^J ^J ^J hi ^J ^J ^A ^J ^d ^A ^J ^J ^J ^J ^1 ^J ^J U U ^J U U U U U U
o o»r»*»»^«»«««f»^»p>f*«"««r^rf»or>«^"io«oa>»rr»e«inlAiN.«'^tOtf1^^r«>*o^O>/^ON'^>»<»'^ri>V'^u^«'«r*'^nr.vr._
I .1
•*^«4A««B*9k9lt*lAV0*V«*tAF*^««««9'^9wa*«*»f>l»^l^v««v*%%AF*(*«*«*
.* oooooooooooooooaoooooooooooooaooooaoooooooooo
m oooooooooooooaooooooooooooooooooaoooooooooooo
« »»•»••»•••••••••*•»••••»••••••»••• — •«.••• — •»»•
OC hlhlhlhlhlhihlWhlhlhlhlhlUhlhlUhlhlhlhlhlhlhlhlhlhlhlhlhlMUUUUhlhlhlhlUUUUUU
•*««^r»f»»»<«»^««-«»««o\«r<«'«—••*o«a«r»r»«oo>f~«>o<««r>^^ro»««r»ion«o
K M»««*oooooooOTmmo»AWp>^«<«<«<«>o«tfitfi^^iir)inin
^
•
• u — — — — — — — «. — — — — — — — — -.« — — — — — — — — — — — — — — — — — — — — -.-. — -._-._
• e ooooooooooooooooooooooooooooooooooooooooooooo
•«• »«****»*•<••**»••»*»•**••«••«••«««..«••«.•«.•».
•J -O UMhlMWhJhlhlhlhlUhlhlhlUUUhlhlhlhlhlhlhlhlhlhlUUUhlhtUUUUUUUUUUUUU
• "^ ^* ^* ^i •< ^P ^S 1*9 ^^ €9 ^* i^ *^ ^* ^* W ^9 ^A ^^ ^0 lO ^P ^i ^* •< ^9 *O ^^ ^* ^9 ^^ ^^ ^^ '^ ^* ^* ^9 ^^ W ^^ • ^ %O ^< ^B r1^
-c "T~?~"
J»M rM.^^^^^mr»p>i'Mr*r»««**M*.^F^«**«f«p*r«p*p»<^f«ri*r"»r>*rii»fl*r>»40^^^ f^ tfl ^> #^ l^ «•% «^ «^ ^« M* ^« ^t .• •• ^ OtftOlOlVW^**^^''1*1^^
5 »
e
s ^a»»«i9«»>o>w^:-^~-«^p-»o>woN<*ff!O>eie<»>oo<«!Oo<^^wij>s>o''!r'
"a — — — — — — —— -- - — — — — __ — — -.-i — _____ — _ — __ _____
3
V
• —
ooooooooo = aeoooooooooooooooooaoooooo. ooooooooo
i aoooooooassaeaacaooooooooooooooooaooooaoooooa
•j .••«••-.--------.--••»..---•-••.-.-••....•----
-------
33d
S«t«*«««««r»<«
•««i«»«OTr»«*m
• >
• w
& •
• *
u
« •
3 "9
C *
S3
B
* o • • o o o o o a o o o o a « o o o o a a • • « • o • o a o a o a o a o o o o o o o o o o
I 3 **»*»**»»»»»»«»»»»»»»«»»»*»»»^»»»»»»»»***»»»»
• MMMMMMMMMMMUMMMMMMMMMMMMUMWUWMWMMMMWWWMMUMHHW
O •M«BMIV<*«»M«t««amo««i>t«BO^m«»M9P><«««««««v><^ain<*t«i«^f<*««*«<»«*
• p» <• •»*»«*« *^» «.<••• o to »»»»>•«• « •••«<••«•••«•••«<(«• •«» • •» •* *» • M i« «n «• « •!*»*» •• o
g
• oaeoeoeeoooooaoeoooeoooaooaooaooeooooaoeoooao
ooaaooaoaaooeooooooaaoooooeooooooaaoooeoooeoo
C a«ooeoooeoaoeaoooaooooooooaeeeeeaoooeeoeaoooo
u r i »i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i > • i i i i i i i i i i i
6 UMUttMUUUUUMMUIilUUUUMUUWUUUMUMUUMUUUUUWUUUUUUUU
U ^* ^B IO IO r^ ^0 V4 ^^ ^h ^B ^9 ^M
i .....
• oooaaoaooaoo
•« »»»**»»•»»»•«
M Itf H bj ^A ^A ^A fci ^A ^t W W ^t
mmoMO««<«<'>v<~<
r »»»»^»»»»»»»
• a oooeoooeoooooeaoooaooeeoooooaooooaao. eeoooeeo
*W U
- a
i w eoooooooaoaooeeooeaaooooooooeooooeooooooooooo
O
u
a
o
e
o
I
ooooooooooooooooeoooaooooooooO'Ooooooooo.ooooo
eeeaeaoaaeeeoeeeoaeeaaoeoeeeeaoeeQeaeoaoeoee
'
-------
33e
e
to
M -H
•a
9 S3
h
o
I
I
VI I
fl^ I
M • I
• > '
• M
• M
* e
M
•
U
a •*
^^ i
i • '
I 3 ***»**»»*»*»••«»»•»••.*.»»»»»»**••••*»•»****»»*
• UMMUUUWUUWMMMWMWUMU-MWMMMUWWMMMUUbllillilWMMMWMMMMM
fl ^ ^ ^ ^ ^ ^ ^ ^ ^ O Irt ^ ^* ** ^ • ^ ^ ^ ^t ^t ^^ 4MO O ^i Irt W ^ ^ O O ««»«««««««»««««««
9 • ,
• e e e e a a o o e e a o o o o o o a o o a. 010 e a o e o o o o a o o o e o o a a a o o a o
o«aoo«oooaoooaeoaaaa o. ar>^««r>«««^«<«vF>>«<«<«M«>r>«o4>i/v«i-«tr>><«inm«^r««««<«v<>tae^p«
I •
M OOOOOOOOOOOOOOOOOOOO OlOia OOOOOOOOQOOOOOOOOOOOOO.
M OOOOOOOOOOOOOOOOOOOO Oi OiO OOOOOOOOOOOOOOOOOOOOOO
•m *««*»«*««»««•««•««»«*.*.»*««•»**••»«•*««««**«»*
M u u ^A ^^ ^A ^A ^M ^j ^j ^A i^ ^£ LJ u ^ ^J ^g ^j £^ ^s ^A ^Al ^A ^A ^A U U ^A Id U ^A U U U ^J U ^t ^1 ^J ^A ^A ^J ^J ^d ^J
4 • _•'•••••••
• 8 OOOOOOOOOOOOOOOOOOOOO- OiO OOOOOOOOOOOOOOOOOOOOOO
M^) UMMMMMHWUUUUUUUUUUMUU UlU uUUUUMUUUUUUUUUUUMUUhlU
!sf 33^*I!^^![;I;""*"»«^^^^^I;I^I»^I!I»^»»^^^I;^I!«I2^
i k. oo**ooooooooooooooooo e.o ooooooooooooaooooooooo
• M hlMUUUUUUUUWWUUUUUUUWU U.U UUUUUUUhlUUUUUUUUUUUUUU
r * ....
• ^^ .
- — - — — — -«- — ______._ _ — « — « . - — _..___ __ — «___._
o
•
M e.
oooooooooooocooooooooooooooooooaooooooooooooo
* 000000000000000000009000000000000000000000000
u •••»•»•--.-•--«•- ••«««*«******«*«*«««*^«*«*««.
e uuuuuuuwuuuuuuuuwuiiiuia u.u UUUUUWWUUUUWUUUMMUUUUU
a)
iH
•H ^v
U C
J= C «
4J 0) -H '
o y *a
m M a)
« a
-------
33f
a
o
«* « o««««o-<>ooo — oaoooooaoooo««QO — — o — — ooo-«oo — ooooooo
« » o«*««o««aa««oaa«ao«oaoaooo«««oooaaoooooaoeaaa
• M •
& • o«««o««ooooaaoooeoo««oooo«ooo«eoooooooooaeooo
• M
• e
M
•
u
14
CM
3u o«r*ooo«ooo*ooooooo
• lrt«»»r«««»«»r«»*«O««v»<«*>»«iO*»<«o«»«»«"«'"O«O««««<^'««"»»««»^»<'»<'>'%«'<«
M ooeooooeeoooeeeaoeeoaeoooeeoaeoooaooooooooooe
I 3 »»»»«»«*****•»•••»»•»»•»»»»••*»»»•»»*»* + **» + »
• UMMMMMWMMhlUWUWUUUWMMMUUUMIiIUUUUIilUhlUMWhjMlilMUUUUU
o f<»irtr««»<««o»n'»^w««»^«««^»p,^, — — — »»,o<«i/ior-i-i«nior««r>««*>r»r»<<^
• & o«toi*w<»«*r>>«"'««ovoooo«omw9i>t««r»«*«B««0ir>«<'i)i«oo<«««i«>a«
e •
o,
•4
X. oooooooooooooooooooeooooooooooooooooooooooooo
U I I I I I I I I I I I I ' I I ' I I I I I I I I I I I I I I I I t I I I I I I I I I I I I
C U M U U U U MUUMWUUUUWUUUUUU M UUUUUMUUUUWUU W U hi hi fal ht^^fr U U
i o r»««>«»«»««>«'''«'«»««i»«"»n>«"«'^r»«o»i«or-r"»«»i'«..»-«'«!«<-'«o*^ifi«<»>r»»<-»<-««»
U "•"•»r«f»"»*»-«"«""»^'>«r»««»^»>fi»»H»s»^W(»»o-"'<»'^i/>«»'^"'««»r»r»'-ir»««»^o>«o
i
j< aeeaoooeoaooooaaooaaaaaaaaooaaeaoaooooaaooaao
• OOQQOOQOOOOOOOQOOOOOQOOOOOOOQOQOOQOOOOOOOOOOO
M »»»••»»»•••••••••••••••»•<,•••»». — ••••••^»»»»»»»*»-
flt UlUMWUMUUlUUUIUUMhIUUMUWUIUUUUUUUMUUUUUUUUUUUblUlUUU
M i* *4 •• •* •* ^B ^9 ^9 ^9 ^9 ^9 ^^ ^B 4k ^B €• ^B ^B ^B 4B 49 ^* ^* ^* ^* ^B ^B ^B ^ ^B ^B W^ Ul ^^ lA IA IA ^1 ^^ *V ^P *^ *^ ^^ ^
<•
•
• e ooooaooooooooooooooooooeooooooooooooooooooooo
« fl UMMMUMMUUUUlUlUUUUUUUUUUUUUUUUWUUUhlUUUUUUUMUIUUU
• ••• iH<«<*i*«tfiM%<«*v*'«1*<**<^aeooaooo«a«r>tf>tfttft^e>«<^>n>ni^<«
«• u <«««»«««»««««i/» — — — »»<«.*»«««^ — ->«m-«OMa. -laeaeaaoooaaeeoooo
*J ** lA *^ •• ^B fl^ «•* ** *^ ^* ^* ^* *^ *rt ^* %O ^* *rt ** M W ••• «M fcft •• ^M ^^ ^ %A ^* ••• ^H ^W ^* •* ^* *» *•* ^M *^ ^«* •* •* ^* •* "^
i •• aoeaaoooaooooaaoeooaoaaooeoaoaaeaaaeoooaooooo
• f> UMUUUUblUUlW_i>lU)UUUUUUUUUMUUUUUI4UWUUUUblUUUUblUUUU
O '*<^>««A«AW^t/l^^M"*u^*O*M«A«^M^OOOOOOOO^O«lnK^t^^A«A^A^^I*^l^t'>*^^^'**'*1'l'*M
& •*•• — — -. — — --> — — — •'-• — ~ — -i— — -.-.«^> — o — o — oooooooooooooooao
3 »
U in^« — — — «««n — — — ^>in — rf> — rf>« — •«._^i — — ,/> — «%«.•-. — — — — « — ^ui — -« — — -• —
•
9 ^^^W^W0*ff*^^^*^^^^^»o\^g*O*ff*3»W0*0*^^^W*^fl*^^WO*W^ff»^^^'3*^'
"a — — — — — — - — — — — — —— - -. — — — — — — — — — —« ——
3
•
* a.
oooaooaooo3oooooooooooooaoaoaoooooo9ooooooooo
•» aeeaeaooo333oaaaeeeeeeoaeeeooeeeaeoa
U *»• — ••••••---••---••••••••••• — •••»»»»*
C UUUUUUUUUU^^wuUUMUUUUUUUUUUUtdUUUUUUUUUUMMUhlUU
£ 0 ^ *^ ^* •• O ^N ^^ ^^ *"** O O ^ W • f^ ^ ^^ ^g ^t f*f ^^ ^| gi 0^ ^» ^» ^ ^^ ^i ^( ^} 0% 4V ^P ^P ^^
•u
o
C
-------
33g
9
O
M
• > oo««m«i«ioooooooooooooooooooooooooooooooooaeooo
• *•
m •
M
•
u
| - j _•_:_:-:_:-:-:-:_:.j-:-:_•_:-:-:_:-:-:_•-:-;-:_:_:-:_•_:_:-:_•_:-;_: .j-:<:_:-;_:-:-:_:_:
i •
I 9
• fe
9
• OOOOOOOOOOOOOQOOOOOOOOOOOOOOOOOOOOOOOOOOQOQOO
••••oovooaaoeaaaeaoooooooeaoaaaaeeaeaaaoaoaoo
a .............................................
a •
•^
r oo««oooooooooooooooooooooooooooooooooooooo«joo
u i i i i i i i i i i i i i i i i i i i i i i i • i i i i i t i i i i i i > i i i i i i i i
i
M ooooooooooooooooooooooooooooooooaoooooooooooo
* OOOOOOQOQOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOQOO
•« »»* + »*»»»*•*»•»»»»»•*•»••»»»••*»*»»••»»**.*»*.»
« UUUMUUUUtilUUUUUUUUUUMWUUWMWUIilUUUIJMWUUfalWUUbtUUUU)
•C ^* ^* ^* ^* f^ ^* ^^ ^* ^* ^* '^ ^* ^** ^* ^V ^P ^B ^P ^P ^P ^B ^P ^P ^P ^P ^P ^P Mf ^P ^P ^P> ^P ^P ^P ^P ^P ^P ^P ^P ^P ^9 ^P ^P ^9 ^
.•
g a ••••••oooooeooooooooeoooooooooooooooooeoooooo
^»4 «M«*«M«A«»«»«M ooooooaoooooooeooooooooeooooaooeooooooooooooo
• i/l UUUUUUUUUUWUUUUUMUUWWUUUUUMWUUMUWUUUUUUUUhJUUU
a « "". ~*. "*. ~*. "". . ~*. ~ ~ ~~.
U ^«»««^fl»^«M^««...«^^«£.«^«^^«...«M.M«.^^.M«M.«^^tn«.^.« in- «M.M.M^M**t»»..-«*M
•
•M ••««•• ••.•••^••M.M^ •• ^^^«B1M.B«.^M»^««««.««. «..«.M ^.«.«.MOT« «M^«W.M
a,
0
•
M ^
oooooeQoooeoooooooooooooooooooooooooooooooooo
V '000000000300000000000000000000000000000000000
e uuwuhiuiuuuuuuuuuwuuuuuuuuuuuuuuuuuuuuuuuuuuuuu
i "T™!"" . , . p "T~
f* f* f% f^ f* f* f^ p* f^ f* *^ 9^ »* f^ ^ ^ ^^ ^B ^A ^p ^M ^p ^p ^p ^B ^p ^p ^p) ^p ^p ^k ^p ^p ^p ^p ^p ^p ^p ^p ^p ^p ^p ^p ^p \^
d
• 01
-C U
O
oo
(1)
-------
33h
3
•
0
eeeeeeeeeeeeeeoeeee
•***»*»»*•»•••»*»**
uuuuuwuuuuuuuuuuuuu
eeeeoeeoeeeeeoeeoee
»»»»^*»»»»»*»*»»»**
UUUUUMUUUUUUIhJUItlWUUU
e
o
a
a.
o
i^ooeeooooooooooeoo
OMOOOOOOO aeooooooo
•••twoooaeoooooooooo
<-< « e «»~«o-»oo
eooeeeaoeooooeeo
e e a o o o o ooeeeeoeo
««eoeeeoeeaoooaee
o —
— a
o
o
1/1
e
o
««
3
c
o
U
OOOO
• •*«.
yuww
vOOOOOOOSC 3 = = =
OO S3 3OS9OOOOO
I I I I I
>
V
L
ooooooooooooooooooo
^^^^•^Illlllllllll1
UUUUhiUUUUUUUUUUUUUU
JOOOOOOOOOOOOOOOOOO
4 •
B -
B *
•3 *
V> X
•
C
.1
9
-------
Appendix B.
Data Concerning Hazard of Fine Mineral Fibers
-------
34a
Chemical Name; asbestos
CAS Number: 1332-21-4
Weight-of-Evidence Classification:1 A
Estimate of Potency (1/ED,J: see comments
Comments: The data used to estimate an ED,0 are derived from numerous epidemiologic studies, but it
is inappropriate to express the ED10 in mg/kg/day equivalents because the carcinogenic
potential is related to specific fiber shapes and sizes and atmospheric concentrations; there
is no direct relationship between air concentrations (fibers/ml) and mass concentrations
(mg/m3 or mg/kg/day).
Source: U.S. Environmental Protection Agency, 1988. Evaluation of the potential carcinogenicity of
asbestos. OHEA-C-073-23. Washington, DC: Office of Health and Environmental
Assessment.
aA-human carcinogen, B1 -probably carcinogenic to humans (limited human evidence), B2-probably
carcinogenic to humans (inadequate human evidence/no human data), C-possibly carcinogenic to humans,
D-not classifiable as to human carcinogenicity, E-evidence of non-carcinogenicrty for humans.
-------
34b
ll V •.'.:- '•.•:•:•'••':•••. '• ^^^^
|| : :: Elements of Hazard linking
Chemical Name: erionite
CAS Number: not applicable
(ARC Classification:* 1
Comments: Studies in humans exposed since birth in areas contaiminated with erionite have
observed high mortality from malignant mesothelioma. Additionally, lung tissue samples from
inhabitants in these areas have shown higher proportions of erionite fibers and ferruginous bodies
than those of controls taken from locations without erionite contamination. The epidemiologic
evidence was considered by IARC as "sufficient evidence" for carcinogenicity to humans.
Erionite has produced increased incidences of mesotheliomas in mice by intraperitoneal injection
and in rats by inhalation, intrapleural, and intraperitoneal administration.
Erionite has been tested in only a few short-term genetic tests. It induced transformation and
unscheduled DNA systhesis in mouse C3H 10T1/2 cells and, in vitro, unscheduled DNA synthesis
in human cells.
Source: International Agency for Research on Cancer, 1987. IARC Monographs on the evaluation
of carcinogenic risks to humans. Supplement 7: 203-205.
"1-the agent is carcinogenic to humans, 2A-the agent is probably carcinogenic to humans (limited
human evidence), 2B-the agent is possibly carcinogenic to humans (limited evidence in humans in
the absence of sufficient evidence in animals, or inadequate human evidence/non-existent human
data and sufficient evidence in animals), 3-the agent is not classifiable as to its carcinogenicity to
humans, 4-the agent is probably not carcinogenic to humans.
-------
34c
Elements ofliazard Racking ; ||
Chemical Name: glasswool
CAS Number: not applicable
I ARC Classification1: 2B
Comments: Two of three epidemiological studies show elevated mortality from repiratory cancer or
lung cancer with occupational exposure to glass wool. Increases were not related to duration of
exposure although one study showed the lung cancer increases were associated with time since
first exposure. A large multinational European study did not observe excesses in lung cancer
mortality when compared to local rates. I ARC considered the epidemioloic data as "inadequate
evidence" for carcinogenicity in humans.
Data in animals are considered "sufficient evidence" for the carcinogenicity of glasswool.
Glasswool has produced increased incidences of lung tumors in rats and lung tumors and
mesotheliomas in hamsters after intratracheal instillation, of pleural tumors in rats given intrapleural
implantation or injection, and of mesotheliomas or sarcomas of the peritoneal cavity in rats with
peritoneal injection.
Glasswool has induced chromosomal alterations but no sister chromatid exchanges in mammalian
cell in vitro and morphological transformations in rodent cells in vivo.
Source: International Agency for Research on Cancer, 1988. IARC Monographs on the evaluation
of carcinogenic risks to humans. Man-made mineral fibres and radon. Volume 43:
39-171.
'1-the agent is carcinogenic to humans, 2A-the agent is probably carcinogenic to humans (limited
human evidence), 2B-the agent is possibly carcinogenic to humans (limited evidence in humans in
the absence of sufficient evidence in animals, or inadequate human evidence/non-existent human
data and sufficient evidence in animals), 3-the agent is not classifiable as to its carcinogenicity to
humans, 4-the agent is probably not carcinogenic to humans.
-------
34d
|: % ':•'•'•:• Bemefits of: Hazard Ranking
Chemical Name: rockwool
CAS Number: not applicable
IARC Classification:' 2B
Comments: The overall classification of 26 is supported by "limited evidence" for carcinogenicity
in humans and "limited evidence" for carcinogenicity in animals.
Among workers exposed to rock-/slagwool, increased mortality from lung cancer was observed
when individual US and European cohorts were combined. Lung cancer risks appeared to increase
(not statistically significant) in the European cohort with time since first exposure; highest risk was
found after more than 20 years latency. No relationship was noted in either study with duration of
exposure. IARC considered these data as "limited evidence" for carcinogenicity in humans.
Rockwool has produced in rats an increase in the incidence of pleural mesotheliomas (not
statistically significant) and in abdominal cavity tumors after intraperitoneal injection. Two other
studies in rats exposed via inhalation did not show any statistically significant increase in lung
tumors. IARC considered these data as "limited evidence" for carcinogenicity in animals.
No adequate data on genetic and related effects of rockwool were available.
Source: International Agency for Research on Cancer, 1988. IARC Monographs on the evaluation
of carcinogenic risks to humans. Man-made mineral fibres and radon. Volume 43:
39-171.
*1-the agent is carcinogenic to humans, 2A-the agent is probably carcinogenic to humans (limited
human evidence), 2B-the agent is possibly carcinogenic to humans (limited evidence in humans in
the absence of sufficient evidence in animals, or inadequate human evidence/non-existent human
data and sufficient evidence in animals), 3-the agent is not classifiable as to its carcinogenicity to
humans, 4-the agent is probably not carcinogenic to humans.
-------
34e
Elf merits of Bazara:Ranking
Chemical Name: slagwool
CAS Number: not applicable
IARC Classification:* 2B
Comments: The overall classification of 2B is supported by "limited evidence" for carcinogenicity
in humans and "inadequate evidence" for carcinogenicity in animals.
Among workers exposed to rock-/slagwool, increased mortality from lung cancer was observed
when individual US and European cohorts were combined. Lung cancer risks appeared to increase
(not statistically significant) in the European cohort with time since first exposure; highest risk was
found after more than 20 years latency. No relationship was noted in either study with duration of
exposure. IARC considered these data as "limited evidence" for carcinogenicity in humans.
Slagwool has produced in rats an increase in the incidence of pleural mesotheiiomas (not
statistically significant) and in abdominal cavity tumors after intraperitoneal injection. Two other
studies in rats exposed via inhalation did not show any statistically significant increase in lung
tumors. IARC considered these data as "limited evidence" for carcinogenicity in animals.
No adequate data on genetic and related effects of slagwool were available.
Source: International Agency for Research on Cancer, 1988. IARC Monographs on the evaluation
of carcinogenic risks to humans. Man-made mineral fibres and radon. Volume 43:
39-171.
*1-the agent is carcinogenic to humans, 2A-the agent is probably carcinogenic to humans (limited
human evidence), 2B-the agent is possibly carcinogenic to humans (limited evidence in humans in
the absence of sufficient evidence in animals, or inadequate human evidence/non-existent human
data and sufficient evidence in animals), 3-the agent is not classifiable as to its carcinogenicity to
humans, 4-the agent is probably not carcinogenic to humans.
------- |