[Code of Federal Regulations]
[Title 40, Volume 26]
[Revised as of July 1, 2005]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR266.106]

[Page 37-41]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
                           AGENCY (CONTINUED)
 
PART 266_STANDARDS FOR THE MANAGEMENT OF SPECIFIC HAZARDOUS WASTES AND 
SPECIFIC TYPES OF HAZARDOUS WASTE MANAGEMENT FACILITIES--Table of Contents
 
   Subpart H_Hazardous Waste Burned in Boilers and Industrial Furnaces
 
Sec. 266.106  Standards to control metals emissions.

    (a) General. The owner or operator must comply with the metals 
standards provided by paragraphs (b), (c), (d), (e), or (f) of this 
section for each metal listed in paragraph (b) of this section that is 
present in the hazardous waste at detectable levels using analytical 
procedures specified in Test Methods for Evaluating Solid Waste, 
Physical/Chemical Methods (SW-846), incorporated by reference in Sec. 
260.11 of this chapter.
    (b) Tier I feed rate screening limits. Feed rate screening limits 
for metals are specified in appendix I of this part as a function of 
terrain-adjusted effective stack height and terrain and land use in the 
vicinity of the facility. Criteria for facilities that are not eligible 
to comply with the screening limits are provided in paragraph (b)(7) of 
this section.
    (1) Noncarcinogenic metals. The feed rates of antimony, barium, 
lead, mercury, thallium, and silver in all feed streams, including 
hazardous waste, fuels, and industrial furnace feed stocks shall not 
exceed the screening limits specified in appendix I of this part.
    (i) The feed rate screening limits for antimony, barium, mercury, 
thallium, and silver are based on either:
    (A) An hourly rolling average as defined in Sec. 
266.102(e)(6)(i)(B); or
    (B) An instantaneous limit not to be exceeded at any time.
    (ii) The feed rate screening limit for lead is based on one of the 
following:
    (A) An hourly rolling average as defined in Sec. 
266.102(e)(6)(i)(B);
    (B) An averaging period of 2 to 24 hours as defined in Sec. 
266.102(e)(6)(ii) with an instantaneous feed rate limit not to exceed 10 
times the feed rate that would be allowed on an hourly rolling average 
basis; or
    (C) An instantaneous limit not to be exceeded at any time.
    (2) Carcinogenic metals. (i) The feed rates of arsenic, cadmium, 
beryllium, and chromium in all feed streams, including hazardous waste, 
fuels, and industrial furnace feed stocks shall not exceed values 
derived from the screening limits specified in appendix I of this part. 
The feed rate of each of these metals is limited to a level such that 
the sum of the ratios of the actual feed rate to the feed rate screening 
limit specified in appendix I shall not ex ceed 1.0, as provided by the 
following equation:

[[Page 38]]

[GRAPHIC] [TIFF OMITTED] TC06NO91.001

where:

n=number of carcinogenic metals
AFR=actual feed rate to the device for metal ``i''
FRSL=feed rate screening limit provided by appendix I of this part for 
metal ``i''.

    (ii) The feed rate screening limits for the carcinogenic metals are 
based on either:
    (A) An hourly rolling average; or
    (B) An averaging period of 2 to 24 hours as defined in Sec. 
266.102(e)(6)(ii) with an instantaneous feed rate limit not to exceed 10 
times the feed rate that would be allowed on an hourly rolling average 
basis.
    (3) TESH. (i) The terrain-adjusted effective stack height is 
determined according to the following equation:

TESH=Ha+H1-Tr

where:

Ha=Actual physical stack height
H1=Plume rise as determined from appendix VI of this part as a function 
of stack flow rate and stack gas exhaust temperature.
Tr=Terrain rise within five kilometers of the stack.

    (ii) The stack height (Ha) may not exceed good engineering practice 
as specified in 40 CFR 51.100(ii).
    (iii) If the TESH for a particular facility is not listed in the 
table in the appendices, the nearest lower TESH listed in the table 
shall be used. If the TESH is four meters or less, a value of four 
meters shall be used.
    (4) Terrain type. The screening limits are a function of whether the 
facility is located in noncomplex or complex terrain. A device located 
where any part of the surrounding terrain within 5 kilometers of the 
stack equals or exceeds the elevation of the physical stack height (Ha) 
is considered to be in complex terrain and the screening limits for 
complex terrain apply. Terrain measurements are to be made from U.S. 
Geological Survey 7.5-minute topographic maps of the area surrounding 
the facility.
    (5) Land use. The screening limits are a function of whether the 
facility is located in an area where the land use is urban or rural. To 
determine whether land use in the vicinity of the facility is urban or 
rural, procedures provided in appendices IX or X of this part shall be 
used.
    (6) Multiple stacks. Owners and operators of facilities with more 
than one on-site stack from a boiler, industrial furnace, incinerator, 
or other thermal treatment unit subject to controls of metals emissions 
under a RCRA operating permit or interim status controls must comply 
with the screening limits for all such units assuming all hazardous 
waste is fed into the device with the worst-case stack based on 
dispersion characteristics. The worst-case stack is determined from the 
following equation as applied to each stack:

    K=HVT

Where:

K=a parameter accounting for relative influence of stack height and 
plume rise;
H=physical stack height (meters);
V=stack gas flow rate (m\3\/second); and
T=exhaust temperature ([deg]K).
The stack with the lowest value of K is the worst-case stack.

    (7) Criteria for facilities not eligible for screening limits. If 
any criteria below are met, the Tier I and Tier II screening limits do 
not apply. Owners and operators of such facilities must comply with 
either the Tier III standards provided by paragraph (d) of this section 
or with the adjusted Tier I feed rate screening limits provided by 
paragraph (e) of this section.
    (i) The device is located in a narrow valley less than one kilometer 
wide;
    (ii) The device has a stack taller than 20 meters and is located 
such that the terrain rises to the physical height within one kilometer 
of the facility;
    (iii) The device has a stack taller than 20 meters and is located 
within five kilometers of a shoreline of a large body of water such as 
an ocean or large lake;
    (iv) The physical stack height of any stack is less than 2.5 times 
the height of any building within five building heights or five 
projected building widths of the stack and the distance from the stack 
to the closest boundary is within five building heights or five 
projected building widths of the associated building; or

[[Page 39]]

    (v) The Director determines that standards based on site-specific 
dispersion modeling are required.
    (8) Implementation. The feed rate of metals in each feedstream must 
be monitored to ensure that the feed rate screening limits are not 
exceeded.
    (c) Tier II emission rate screening limits. Emission rate screening 
limits are specified in appendix I as a function of terrain-adjusted 
effective stack height and terrain and land use in the vicinity of the 
facility. Criteria for facilities that are not eligible to comply with 
the screening limits are provided in paragraph (b)(7) of this section.
    (1) Noncarcinogenic metals. The emission rates of antimony, barium, 
lead, mercury, thallium, and silver shall not exceed the screening 
limits specified in appendix I of this part.
    (2) Carcinogenic metals. The emission rates of arsenic, cadmium, 
beryllium, and chromium shall not exceed values derived from the 
screening limits specified in appendix I of this part. The emission rate 
of each of these metals is limited to a level such that the sum of the 
ratios of the actual emission rate to the emission rate screening limit 
specified in appendix I shall not exceed 1.0, as provided by the 
following equation:
[GRAPHIC] [TIFF OMITTED] TC06NO91.002

where:

n=number of carcinogenic metals
AER=actual emission rate for metal ``i''
ERSL=emission rate screening limit provided by appendix I of this part 
for metal ``i''.

    (3) Implementation. The emission rate limits must be implemented by 
limiting feed rates of the individual metals to levels during the trial 
burn (for new facilities or an interim status facility applying for a 
permit) or the compliance test (for interim status facilities). The feed 
rate averaging periods are the same as provided by paragraphs (b)(1)(i) 
and (ii) and (b)(2)(ii) of this section. The feed rate of metals in each 
feedstream must be monitored to ensure that the feed rate limits for the 
feedstreams specified under Sec. Sec. 266.102 or 266.103 are not 
exceeded.
    (4) Definitions and limitations. The definitions and limitations 
provided by paragraph (b) of this section for the following terms also 
apply to the Tier II emission rate screening limits provided by 
paragraph (c) of this section: terrain-adjusted effective stack height, 
good engineering practice stack height, terrain type, land use, and 
criteria for facilities not eligible to use the screening limits.
    (5) Multiple stacks. (i) Owners and operators of facilities with 
more than one onsite stack from a boiler, industrial furnace, 
incinerator, or other thermal treatment unit subject to controls on 
metals emissions under a RCRA operating permit or interim status 
controls must comply with the emissions screening limits for any such 
stacks assuming all hazardous waste is fed into the device with the 
worst-case stack based on dispersion characteristics.
    (ii) The worst-case stack is determined by procedures provided in 
paragraph (b)(6) of this section.
    (iii) For each metal, the total emissions of the metal from those 
stacks shall not exceed the screening limit for the worst-case stack.
    (d) Tier III and Adjusted Tier I site-specific risk assessment. The 
requirements of this paragraph apply to facilities complying with either 
the Tier III or Adjusted Tier I controls, except where specified 
otherwise.
    (1) General. Conformance with the Tier III metals controls must be 
demonstrated by emissions testing to determine the emission rate for 
each metal. In addition, conformance with either the Tier III or 
Adjusted Tier I metals controls must be demonstrated by air dispersion 
modeling to predict the maximum annual average off-site ground level 
concentration for each dispersion modeling to predict the maximum annual 
average off-site ground level concentration for each metal, and a 
demonstration that acceptable ambient levels are not exceeded.
    (2) Acceptable ambient levels. Appendices IV and V of this part list 
the acceptable ambient levels for purposes of this rule. Reference air 
concentrations (RACs) are listed for the noncarcinogenic metals and 
10-5 risk-specific doses (RSDs) are listed for the 
carcinogenic

[[Page 40]]

metals. The RSD for a metal is the acceptable ambient level for that 
metal provided that only one of the four carcinogenic metals is emitted. 
If more than one carcinogenic metal is emitted, the acceptable ambient 
level for the carcinogenic metals is a fraction of the RSD as described 
in paragraph (d)(3) of this section.
    (3) Carcinogenic metals. For the carcinogenic metals, arsenic, 
cadmium, beryllium, and chromium, the sum of the ratios of the predicted 
maximum annual average off-site ground level concentrations (except that 
on-site concentrations must be considered if a person resides on site) 
to the risk-specific dose (RSD) for all carcinogenic metals emitted 
shall not exceed 1.0 as determined by the following equation:
[GRAPHIC] [TIFF OMITTED] TC06NO91.003

where: n=number of carcinogenic metals

    (4) Noncarcinogenic metals. For the noncarcinogenic metals, the 
predicted maximum annual average off-site ground level concentration for 
each metal shall not exceed the reference air concentration (RAC).
    (5) Multiple stacks. Owners and operators of facilities with more 
than one on-site stack from a boiler, industrial furnace, incinerator, 
or other thermal treatment unit subject to controls on metals emissions 
under a RCRA operating permit or interim status controls must conduct 
emissions testing (except that facilities complying with Adjusted Tier I 
controls need not conduct emissions testing) and dispersion modeling to 
demonstrate that the aggregate emissions from all such on-site stacks do 
not result in an exceedance of the acceptable ambient levels.
    (6) Implementation. Under Tier III, the metals controls must be 
implemented by limiting feed rates of the individual metals to levels 
during the trial burn (for new facilities or an interim status facility 
applying for a permit) or the compliance test (for interim status 
facilities). The feed rate averaging periods are the same as provided by 
paragraphs (b)(1) (i) and (ii) and (b)(2)(ii) of this section. The feed 
rate of metals in each feedstream must be monitored to ensure that the 
feed rate limits for the feedstreams specified under Sec. Sec. 266.102 
or 266.103 are not exceeded.
    (e) Adjusted Tier I feed rate screening limits. The owner or 
operator may adjust the feed rate screening limits provided by appendix 
I of this part to account for site-specific dispersion modeling. Under 
this approach, the adjusted feed rate screening limit for a metal is 
determined by back-calculating from the acceptable ambient level 
provided by appendices IV and V of this part using dispersion modeling 
to determine the maximum allowable emission rate. This emission rate 
becomes the adjusted Tier I feed rate screening limit. The feed rate 
screening limits for carcinogenic metals are implemented as prescribed 
in paragraph (b)(2) of this section.
    (f) Alternative implementation approaches. (1) The Director may 
approve on a case-by-case basis approaches to implement the Tier II or 
Tier III metals emission limits provided by paragraphs (c) or (d) of 
this section alternative to monitoring the feed rate of metals in each 
feedstream.
    (2) The emission limits provided by paragraph (d) of this section 
must be determined as follows:
    (i) For each noncarcinogenic metal, by back-calculating from the RAC 
provided in appendix IV of this part to determine the allowable emission 
rate for each metal using the dilution factor for the maximum annual 
average ground level concentration predicted by dispersion modeling in 
conformance with paragraph (h) of this section; and
    (ii) For each carcinogenic metal by:
    (A) Back-calculating from the RSD provided in appendix V of this 
part to determine the allowable emission rate for each metal if that 
metal were the

[[Page 41]]

only carcinogenic metal emitted using the dilution factor for the 
maximum annual average ground level concentration predicted by 
dispersion modeling in conformance with paragraph (h) of this section; 
and
    (B) If more than one carcinogenic metal is emitted, selecting an 
emission limit for each carcinogenic metal not to exceed the emission 
rate determined by paragraph (f)(2)(ii)(A) of this section such that the 
sum for all carcinogenic metals of the ratios of the selected emission 
limit to the emission rate determined by that paragraph does not exceed 
1.0.
    (g) Emission testing--(1) General. Emission testing for metals shall 
be conducted using Method 0060, Determinations of Metals in Stack 
Emissions, EPA Publication SW-846, as incorporated by reference in Sec. 
260.11 of this chapter.
    (2) Hexavalent chromium. Emissions of chromium are assumed to be 
hexavalent chromium unless the owner or operator conducts emissions 
testing to determine hexavalent chromium emissions using procedures 
prescribed in Method 0061, Determination of Hexavalent Chromium 
Emissions from Stationary Sources, EPA Publication SW-846, as 
incorporated by reference in Sec. 260.11 of this chapter.
    (h) Dispersion Modeling. Dispersion modeling required under this 
section shall be conducted according to methods recommended in appendix 
W of part 51 of this chapter (``Guideline on Air Quality Models 
(Revised)'' (1986) and its supplements), the ``Hazardous Waste 
Combustion Air Quality Screening Procedure'', provided in appendix IX of 
this part, or in Screening Procedures for Estimating the Air Quality 
Impact of Stationary Sources, Revised (incorporated by reference in 
Sec. 260.11) to predict the maximum annual average off-site ground 
level concentration. However, on-site concentrations must be considered 
when a person resides on-site.
    (i) Enforcement. For the purposes of permit enforcement, compliance 
with the operating requirements specified in the permit (under Sec. 
266.102) will be regarded as compliance with this section. However, 
evidence that compliance with those permit conditions is insufficient to 
ensure compliance with the requirements of this section may be 
``information'' justifying modification or revocation and re-issuance of 
a permit under Sec. 270.41 of this chapter.

[56 FR 7208, Feb. 21, 1991; 56 FR 32689, July 17, 1991; 57 FR 38565, 
Aug. 25, 1992; 58 FR 38883, July 20, 1993; 62 FR 32463, June 13, 1997]

    Effective Date Note: At 70 FR 34588, June 14, 2005, Sec. 266.106 
was amended by revising paragraph (a), effective July 14, 2005. For the 
convenience of the user, the revised text is set forth as follows:

Sec. 266.106  Standards to control metals emissions.

    (a) General. The owner or operator must comply with the metals 
standards provided by paragraphs (b), (c), (d), (e), or (f) of this 
section for each metal listed in paragraph (b) of this section that is 
present in the hazardous waste at detectable levels by using appropriate 
analytical procedures.

                                * * * * *