& EPA
United States Solid Waste and
Environmental Protection Emergency Response EPA530-F-94-033
Agency (5305) November 1994
Status of Rulemaking
on Emissions
Standards and Controls
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STATUS OF RULEMAKING ON EMISSIONS STANDARDS AND CONTROLS
The Agency is in the process of upgrading its emissions
standards controls for hazardous waste combustors (HWCs).
Revised regulations for incinerators, cement kilns, light-weight
aggregate kilns, and metals recovery furnaces are scheduled to be
proposed in September 1995 and promulgated in December 1996.
Revised regulations for other HWCs, such as boilers and halogen
acid furnaces are scheduled to be proposed in September 1998 and
promulgated in December 1999. The Agency is making every effort
to beat these schedules, and hopes that it may be possible to
include revised regulations for boilers as part of the first
phase of the rulemakings.
Concerns with Existing ControIs
EPA established emissions standards and controls for
hazardous waste incinerators in 1981 and for boilers and
industrial furnaces (BIFs) burning hazardous waste in 1991.
Given that the regulatory emission standards for BIFs are more
comprehensive than the standards for incinerators (e.g., the BIF
rules establish emission limits for toxic metals while the Agency
must rely on its omnibus permit authority to control toxic metals
from incinerators), the Agency proposed in 1989 to revise the
incinerator standards to conform with the (at that time) proposed
BIF standards. The Agency has never finalized the proposed
standards for incinerators.
The Agency believes that emissions standards and controls
for HWCs should be upgraded for several reasons. First, the
Agency is concerned that the current regulations may not always
ensure that HWCs use best operating practices to minimize
emissions of hazardous air pollutants. Standards for some
pollutants (e.g., metals, HC1, C12) are based on levels that will
not result in significant health risk considering exposure via
inhalation. The levels of protection provided by such standards
is problematic, however, because some pollutants can pose health
risks via means of exposure other than inhalation, such as uptake
through the food chain. In addition, HWCs can often meet the
risk-based standards without using good operating practices. (To
address these two points, the Agency is requiring that a risk
assessment be conducted, including indirect exposure, before a
permit decision is made.)
Second, the current regulations do not establish limits for
chlorinated dioxins and furans (D/Fs) for most HWCs. Although
the current regulations establish risk-based limits for D/Fs for
BIFs that operate under certain conditions, most HWCs are not
subject to explicit D/F emission limits. Given the high toxicity
of some D/F congeners and the fact that good operating conditions
alone may not always control emissions of D/Fs, EPA believes that
emission limits are necessary. As discussed below, the Agency's
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intent is to develop revised technology-based emission limits for
D/F for HWCs.
Finally, the Agency has agreed to propose upgraded emissions
standards for HWCs under a Settlement Agreement resulting from
litigation on the BIF rule. The rulemaking schedule discussed
above was established in that Settlement Agreement.
Promulgation under Joint RCRA and CAA Authority
The Agency intends to develop the technical emissions
standards for HWCs under Resource Conservation and Recovery Act
(RCRA) and the Clean Air Act (CAA) authorities. This is because
the Agency has already targeted several types of HWCs (i.e.,
incinerators, boilers, cement kilns) as source categories under
Section 112 of the CAA. Thus, the Agency is reguired to
establish National Emission Steindards for Hazardous Air
Pollutants (NESHAPs) for these HWCs. Under Section 112, the
Agency will establish Maximum Achievable Control Technology
(MACT) standards for these source categories. Given that the
Agency is mandated to regulate several types of HWCs under both
the CAA and RCRA, the Agency's intent is to promulgate the
upgraded standards under joint authority. This will minimize the
regulatory development burden on the Agency and minimize the
burden on the regulated community by avoiding piecemeal or
sequential regulation.
EPA's Office of Solid Waste is coordinating with the Office
of Air and Radiation in developing the emissions standards. To
ensure that it also meets its RCRA mandate, the Agency is
considering options to address the residual risk that would
result from compliance with the MACT standards. The options
being considered include using representative facilities to
evaluate the residual risk (considering multi-pathway exposures)
that could be posed after compliance with the MACT standards
and/or use of site-specific risk assessments.
To regulate all HWCs under joint CAA and RCRA authority, the
Agency plans to propose adding to the list of MACT source
categories those types of HWCs that are not currently on the list
(e.g., light-weight aggregate kilns). These proposals would be
announced concurrently with the proposed emission standards.
HAPs to be Regulated
The hazardous air pollutants (HAPs) that the Agency is
considering regulating under the rulemakings are: chlorinated
dioxins/furans (D/Fs); 11 toxic metals; non-D/F toxic organic
compounds; HCl and C12. In addition, the Agency is considering
whether to establish emission limits for particulate matter (PM),
either to supplement its controls for toxic metals or to
supplement its controls for toxic organic compounds (i.e.,
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beceiuse some organics condense on PM and can be controlled by
controlling PM). Further, the Agency is considering using
surrogates (e.g., carbon monoxide, total hydrocarbons) to control
emissions of non-D/F toxic organics given the impracticability of
limiting dozens of individual organic compounds. Under this
approach, MACT standards would be established for the
surrogate(s).
Enhanced Monitoring
The Agency is undertaking a substantial effort to accelerate
the development and commercial availability of continuous
emissions monitors (CEMs). Full-scale testing is scheduled in
January 1995 for three PM CEMs. In addition, the Agency has
applied for funding in 1995 through the Environmental Technology
Initiative to pursue the development and validation of a multi-
metals CEM. Finally, the Agency is considering the
practicability of field testing in early 1995 CEMs for organic
compounds (e.g., a CEM for polycyclic aromatic hydrocarbons
(PAHs)).
Progress to Date
CETRED. In May 1994, EPA released a Combustion Emissions
Technical Resource Document (CETRED) that presented a preliminary
technical analysis of available dioxin and furan (D/F) and
particulate matter (PM) emissions data from existing hazardous
waste combustion facilities. EPA released CETRED to give the
regulated community and othet interested persons the earliest
possible opportunity to understand the nature of the technical
analysis that EPA is pursuing. The Agency received approximately
30 comments on the document, and will carefully consider those
comments as it continues with the analyses to develop and support
MACT emission standards.
Emissions Testing Program. To better understand the
capabilities of control technologies, the Agency is developing an
extensive emissions testing program. To date, the Agency plans,
among others, to conduct the following tests: (1) PM and metals
controls achievable with an add-on control device to an
incinerator with a wet control system; (2) D/F formation
mechanisms and control options for cement kilns, including the
use of inhibitors and the relationship between chlorine in the
feed and D/F emissions. This and other testing is scheduled to
be conducted in January-March 1995.
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