|(a) General. For closure/remediation in accordance with Risk
Reduction Standard Number 3, persons shall propose media cleanup levels in
accordance with the conditions set forth in subsections (b) - (j) of this
(b) Carcinogens. For known or suspected carcinogens, media
cleanup levels shall be established at concentrations which represent an excess
upperbound lifetime risk of between one in 10,000 and one in one million.
The executive director will use one in one million as a goal in establishing
such concentration limits. The cumulative excess risk to exposed populations
(including sensitive subgroups) shall not be greater than one in 10,000.
(c) Systemic toxicants. For systemic toxicants, media cleanup
levels shall represent concentrations to which the human population (including
sensitive subgroups) could be exposed on a daily basis without appreciable
risk of deleterious effect during a lifetime or part of a lifetime and where:
(1) the hazard quotient, which is the ratio of a single systemic
toxicant exposure level for a specified time period to a reference dose for
that systemic toxicant derived from the same time period, shall not exceed
(2) the hazard index shall not exceed one. The hazard index
is the sum of the hazard quotients for a single or multiple systemic toxicants
which affect the same target organ or act by the same method of toxicity and
act through a single or multiple media exposure pathways.
(d) Additional considerations. In establishing media cleanup
levels pursuant to subsections (b) and (c) of this section, the executive
director may consider and may direct persons who submit plans or reports in
accordance with §335.553(b) of this title (relating to Required Information)
to address the following:
(1) multiple contaminants in a medium;
(2) exposure to multiple contaminated media;
(3) reasonable expected future exposure conditions at the facility;
(4) the technical limitations, effectiveness, practicability,
or other relevant features of available remedies.
(e) Standard exposure factors. In determining media cleanup
levels pursuant to subsections (b) and (c) of this section, persons shall
use the standard exposure factors for residential use of the facility as set
forward in Table 1 (located in §335.553 of this title) unless the person
documents to the satisfaction of the executive director that:
(1) site-specific data warrant deviation from the standard
exposure factors; or
(2) a land use other than residential is more appropriate based
(A) historical, current, and probable future land use; and
(B) effectiveness of institutional or legal controls placed
on the future use of the land.
(f) Air. Media cleanup levels for air will be established to
meet the lowest of the values determined by the requirements of paragraphs
(1) - (3) of this subsection.
(1) Concentrations of contaminants in air that emanate from
a facility, area of soil contamination, or plume of contaminated groundwater
shall not exceed:
(A) National Ambient Air Quality Standards (NAAQS), National
Emission Standards for Hazardous Air Pollutants (NESHPAS) (as found in 40
Code of Federal Regulation Parts 50 and 61 respectively) and other applicable
federal standards and guidelines of the Environmental Protection Agency; and
(B) concentrations established by the commission under the
Texas Clean Air Act, the state implementation plan, or other federal requirements.
Permit requirements, limitations established by standard exemptions, or other
requirements relative to atmospheric emissions and/or air quality may also
(2) For residential exposure conditions, concentrations of
contaminants in air that emanate from a facility, area of soil contamination,
or plume of contaminated ground water shall not exceed concentrations that
satisfy subsections (b) - (e) of this section at exposure points located both
within the contaminated area and at the property boundary.
(3) For nonresidential exposure conditions, concentrations
of contaminants in air that emanate from a facility, area of soil contamination,
or plume of contaminated groundwater shall not exceed either OSHA permissible
exposure limits, threshold limit values or other criteria applicable to an
industrial exposure setting within the facility boundaries or concentrations
that satisfy subsections (b) - (e) of this section at the property boundary.
(g) Surface water. In determining the necessity for remediation
at the facility, persons shall utilize Chapter 307 of this title (relating
to Texas Surface Water Quality Standards) or, if those values are not available,
maximum contaminant levels (MCLs) promulgated under the Safe Drinking Water
Act or, if MCLs are not available or appropriate, values calculated pursuant
to subsections (b) - (e) of this section based upon human ingestion of the
water or other site-specific exposure pathway. Any discharge or release into
or adjacent to surface water, including storm water runoff, occurring during
or after attainment of Risk Reduction Standard Number 3, shall be compliant
with Chapter 307 of this title and may be subject to the permitting requirements
of Chapter 305 of this title (relating to Consolidated Permits) or other authorization
from the commission.
(h) Groundwater. Media cleanup levels for groundwater that
is a current or potential source of drinking water as defined in paragraph
(1) of this subsection shall not exceed MCLs promulgated under the Safe Drinking
Water Act or, if MCLs are not available, values calculated according to subsections
(b) - (e) of this section based upon human ingestion of the water. Cleanup
levels for groundwater may be subject to the modifications of paragraphs (2)
- (4) of this subsection.
(1) Groundwater that has a background total dissolved solids
(TDS) content less than or equal to 10,000 milligrams per liter (mg/L) and
that occurs within a geologic zone that is sufficiently permeable to transmit
water to a pumping well in usable quantities shall be considered a current
or potential source of drinking water for the purpose of determining cleanup
(2) The cleanup levels shall be achieved throughout the plume
of contaminated groundwater, with the exception of the circumstances described
in subparagraphs (A) - (C) of this paragraph:
(A) when alternate concentration limits of §335.160(b)
of this title (relating to Alternate Concentration Limits) have been approved
in a permit issued by the commission for a hazardous waste management facility;
(B) when the selected remedy calls for waste to be left in
place and when appropriate control measures are installed or operated, the
executive director may authorize the zone underlying the area encompassing
the original source(s) of release to be excluded from this requirement;
(C) when the person documents to the executive director's satisfaction
pursuant to subsection (e) of this section that a future land use other than
residential is appropriate for the facility or area and further demonstrates
that institutional or legal controls will effectively prevent use of the contaminated
groundwater, the extent of plume remediation may be determined in a manner
consistent with §335.160(b) of this title.
(3) The executive director may determine that remediation of
groundwater to the extent required in paragraphs (1) or (2) of this subsection
is not necessary if the person demonstrates to the executive director's satisfaction
(A) the contaminant is present in groundwater that is not a
current or potential source of drinking water and the contaminated groundwater
is not hydraulically connected with and is not likely to migrate to either
surface water or to groundwater that is a current or potential source of drinking
(B) restoration of the groundwater to these levels is technically
(4) If a determination is made pursuant to paragraph (3) of
this subsection, the executive director may require any alternative measures
or cleanup levels that are necessary to protect human health and the environment.
At a minimum, for all cases described in this subsection, phase-separated
non-aqueous liquids shall be removed from groundwater zones to the extent
(i) Soil. Concentrations of contaminants in soil shall not
exceed the following values:
(1) the values calculated pursuant to subsections (b) - (d)
of this section based upon human ingestion of the soils at all points where
direct contact exposure to the soils may occur; and
(2) values which will allow the air, surface water, and groundwater
cleanup levels specified in subsections (f) - (h) of this section, respectively,
to be maintained over time taking into account the effects of engineering
(A) Such determinations shall be based on sound scientific
principles including fate and transport evaluation of contaminant migration.
Procedures and conclusions shall be documented to the satisfaction of the
(B) The executive director may require the evaluation of additional
migration pathways beyond those listed in this section if determined necessary.
Such additional pathways may include but are not limited to, food chain contamination,
impairment of soil for agricultural purposes, phytotoxicity, accumulations
of contaminants in sediment of surface water bodies, or other impairments
of natural resources, land, or water use.
(j) Other adjustments. Cleanup levels may be adjusted according
to paragraphs (1) - (3) of this subsection.
(1) If the practical quantitation limit (PQL) or the background
concentration (represented by results of analyses of samples taken from media
that are not affected by waste management or industrial activities) for a
contaminant is greater than the cleanup level determined by procedures of
this section, then the greater of the PQL or background shall become the cleanup
(2) Other scientifically valid published criteria, such as,
but not limited to threshold limit values for air and secondary maximum contaminant
levels for water, shall be utilized as cleanup levels for contaminants for
which the procedures of this section are not appropriate (e.g., mixtures or
substances that do not have toxicological data) or that do not exceed standards
or criteria protective of human health as determined by the procedures of
this section but otherwise adversely impact environmental quality, or the
public welfare and safety, or present objectionable characteristics (e.g.,
taste, odor, etc.), or make a natural resource unfit for use.
(3) More stringent cleanup levels may be established for a
facility than are specified in this section if, by utilizing available guidance
or scientific literature, the executive director determines that it is necessary
to protect environmental receptors.