the best way to improve public health protection because of
the substantial differences in population densities {n the
vicinity of plants. In addition, of course, even a “costeffective” emission reduction when appraised in terms of
public health gains achieved may involve too much or too
little control of these plants, this is because theinitial level
of control was determined without reference to levels of
control that would be considered “reasonable.” ~
2. Subcategorization by Population Exposure
EPA recognizes that its reliance on a BAT approach
focuses on the “feasibility” of installing specific control
technologies and that little consideration is given to the
likely exposure and health risks associated with emissions
from these plants.” As EPA notes in its preamble, there are
substantial variations across plants in terms of public exposure and health risk. As a result, EPA discusses two alternative ways of taking this information into consideration in
setting standards for source categories posing “significant”
risks. One alternative would be to subdivide source categories on the basis of population density before determining
BAT. Within high population density areas (for illustrative
purposes, EPA uses a population cutoff of 10,000 persons
within 20 kilometers), BAT level controls would be more
stringent than for plants within low population density
areas. EPA’s second alternative would subdivide sources
into higher-risk, lower-risk categories by using risk assessment information for both individua] risk and aggregate
cancerincidence (see Table IV for the risk-exposure cutoffs
used by EPA). Under this alternative, higher-risk facilities
would be required to install BAT while lower-risk smelters
would not be regulated.
;
We support EPA's effort to consider additional information on public exposure and health risk in setling standards.
We think that consideration of this kind of information is
essential to sound public health regulation. However, we are
concerned about the way in which EPA proposes to use this
information as a part of the standard-setting process. Under
EPA's two alternative approaches, exposure and health risk
information would be used to establish separate subcategorjes of sources, and EPA would then determine the level of
control representing BAT for each “risk” subcategory. For
example, EPA suggests that it might establish a lower feed
rate cutoff—that is, a more stringent regulatory cutoff —for
plants located in high density population areas. This would
require some plants in high density areas to contro! emissions while plants with similar operating characteristics in
low density areas would not be required to control their
emissions further. Again, it is unclear what criteria EPA
would rely upon in setting BAT standards for plants falling
in one or the other subcategory." It appears, though, that
EPA would continue to rely on a technology-based approach
in determining the appropriate level of control within the
“high” and “low” risk subcategories.
“" In setting BAT requirements for copper smelters in high popula-
tion density areas, EPA would require control of the secondary
emissions from matte and slag operations at the Kennecott-Garfield
plant at an estimated removal cest of $302,000 per Mg of arsenic
removed: but, EPA would not require control of the smelter’s
secondary emissions from converter operations even though the
estimated removal cost is only $185,000 per Mg. 48 FR 33143-33144.
"48 FR 33145.
*
r
| Table Iv
.
4
ro’
Alternative aporcach
ms
#
sea
:
:
~ le wt
-s3
Risk
ané SCareosere
Cucsifs
Once
A.
Population Censity
If the Scpulation
Density within 20 km
is Greater
PB.
than 10,000
The Smelter
Would be Clzssified
“Higher Risk”
Risk/dealicth Effects Catofés
23
AND
The Expected Annual
Cancer Incidence is
Greater than:
ta
3£ the Maximus
Individual Risk
is Greater than:
0.0024
toTe
¢.0014
an
-
wg7F
oe.
“The Smelter
would te Classified
TYEN
"digher Risk”
0.0140
107
i¢75
0.0140
0.1400
197?
1.4000
Ssurce:
1-13-84
THEN
48 FR 33146-33147.
Environment Reporter
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