—
Ill. Intent to Propose Withdrawal of Proposed Stan-
dards for Three SourceCategories (maleic anhydride
plants, ethylbenzene and styrene plants, and benzene
storage vessels):
EPA's decision to withdraw the proposed standards for
these source categories is based on the conclysion that
regulatory action is sot warranted at the nationa) level
because the health risks from benzene from these categories
in the absence of federal regulations appear sma) and they
would not be appreciably reduced by the proposed regulation. For comparison, the risks from these sources to the
most exposed individuals and the population as a whole are
esiimated to be 10 to 100 times lower than for the two
benzene source categories which the agency intends to
regulate.
. Since the agency proposed standards for these source
categories in 1980, the potential number of sources affected
by the maleic anhydride standard, and the emission estimates for all three source categories, have declined signifi-
cantly. These changes have occurred as a result of closures,
process changes, improved estimates, and the voluntary
application of controls from both regulatory and economic
. Many of the sources that would have been affected
By the standards EPA proposes to withdraw would now be
considered to be in compliance with the standard because of
these changes. These changes have resulted in reductions in
the estimated before-control individual and population
health risks associated with each source category. For example, for benzene storage facilities, the estimated lifetime +4
&q
risk lo the most exposed individual has declined over tenfold’
to 3.6 in 100,000. Expected cancer incidence from benzene a
exposure for all three source categories is only one case rJ
every 13 years. Moreover, were EPA to issue the proposed
standards for these categories, it would eliminate’ only one
cancer case every 30 years.
EPAestimated that issuance of the standard for the three
source categories would affect only 3.3 percent of the total
benzene emissions from stationary sources.
SOTAOF FIVE DUCE GCL
Boat TO SEQUELS UXben Serr ton 112
Caroury
Serene
itive
Core
By-product
:
teker of
Tristing
Facilities
Total
Brissions
Stationsry
{teqeqgrans/year) Source
Selore / After
missions
Aaximun Lifet ine
Indivicss: Risk
Scfore / After
Zz
7,900
2,300
184
15/10,0U8
$s
27,000
83,500
si
4/10,00
,
deuce Cancer Cooes
Before / Aiter/Ditference
Cos:
(millions)
Cacital/A-mel
4.5/10,000
6.45
6.14
on
$5.5
0.4
3.5/10,000
2.69
6.23
2.37
3%.
62.3)
©.023
96.016
6.013
6.4
2.8
@.0057
6.00058
6.0051
2.7
0.77
6.043
6.028
0.015
7.3
1.3
rte TO PROMS! WITHOUAL OF PINOT D STANLARTS
Maiete
arnycride
thyLbonsene/
styrene
Serusne
storey
3
a]
420
wt
3
210
e
@.40
126
620
sou
.
Wfailiion
S.Vealliien
oS
.
«= 140faillion $.0/niliion
,
180: 3..6/100,000 2.3/100,000
12-23-83
nen re ee ee ee