Current through Register Vol. 6, March 22, 2024
(1) The department
shall categorize all releases from USTs and PSTs regulated under this chapter
as active, transferred, resolved, ground water management, or resolved with a
petroleum mixing zone releases.
(2)
Releases that do not meet the criteria set forth in (3), (4), (7), or (10) must
be categorized as active.
(3) The
department may categorize a release as transferred if another state or federal
program assumes jurisdiction over the facility and all releases and threatened
releases of hazardous or deleterious substances from USTs or PSTs regulated
under this chapter are to be addressed by that program at the facility. The
department shall notify the owner or operator before categorizing the release
as transferred. The notice must state which state or federal program has
jurisdiction over the release.
(4)
The department may categorize a release as resolved if the department has
determined that all cleanup requirements have been met and that conditions at
the site ensure present and long-term protection of human health, safety, and
the environment. The following requirements must also be met before a release
may be categorized as resolved:
(a) documented
investigations, conducted in accordance with ARM
17.56.604, identify the extent or
absence of contamination in the soil, ground water, surface water, and other
environmental media relevant to the release;
(b) risks to human health, safety and the
environment from residual contamination at the site have been evaluated using
methods listed in (4)(b)(i) or (ii) and the evaluation indicates that
unacceptable risks do not exist and are not expected to exist in the future.
The department considers a total hazard index that does not exceed 1.0 for
noncarcinogenic risks, and a total cancer risk that does not exceed 1 x
10-5, to be an acceptable risk level. Owners or
operators, or other persons may, with department approval, use either of the
following methods to evaluate risks from a release:
(i) Tier 1 evaluation using Montana
Risk-based Correction Action Guidance for Petroleum Releases (RBCA) for
evaluation of risks to human health, safety and the environment associated with
surface and subsurface soil and ground water contamination; or
(ii) a site-specific risk assessment method
approved by the department for evaluation of risks to human health, safety, and
the environment associated with contamination, or likely contamination, that
demonstrates to the department's satisfaction that current and potential future
exposure pathways are incomplete;
(c) all appropriate corrective actions
associated with the release and required by the department, including
compliance monitoring and confirmatory sampling, have been completed;
(d) all free product has been removed to the
maximum extent practicable; and
(e)
all applicable environmental laws associated with the release have been met.
These applicable requirements may include, but are not limited to, air quality,
drinking water and monitoring well requirements, solid waste management
requirements, hazardous waste management requirements, national pollutant
discharge elimination system (NPDES) and Montana pollutant discharge
elimination system (MPDES) requirements, underground injection controls and
standards, UST requirements, noxious weed control, ground water and surface
water quality standards, nondegradation requirements, storm water requirements,
and requirements for the protection of endangered species, historic sites,
wetlands and floodplains.
(5) The department may recategorize a
resolved or a resolved with a petroleum mixing zone release as active if the
department receives information with which it determines that further
corrective action is necessary. Such information may include, but is not
limited to, changes in land use or site conditions, including removal,
alteration, or failure to maintain department-approved institutional controls,
engineering controls, or physical conditions, that may increase the potential
for adverse impacts to human health, safety, or to the environment from
residual contamination. The department shall notify the owner or operator of
the department's determination to recategorize a resolved release as
active.
(6) If a release is
categorized as resolved, the department shall send a letter to the owner or
operator that:
(a) states that, based on
information available, no further corrective action will be required at that
time;
(b) requires that all
monitoring wells, piezometers, and other ground water sampling points either be
abandoned or maintained by the owner or operator in accordance with applicable
rules and requirements;
(c)
describes the nature, extent, concentration, and location of any residual
contamination;
(d) describes any
institutional controls, engineering controls, or physical conditions that must
be maintained to protect human health, safety, or the environment from residual
contamination;
(e) states the
reasons why the department believes the release does not pose a present or
future risk to human health, safety, or to the environment; and
(f) states that the department reserves the
right to conduct or to require further corrective action if a new release
occurs or if the department receives new or different information related to
the release.
(7) The
department may categorize a release as ground water management if:
(a) site conditions satisfy all criteria
listed under (4)(a) and (d);
(b)
risk evaluations conducted in accordance with (4)(b) demonstrate that there are
no unacceptable risks to human health, safety, ecological receptors, surface
water, or aquatic sediments from exposure or likely exposure to contamination;
(c) all cleanup actions required
by the department have been completed except for continued monitoring required
under (8);
(d) ground water quality
parameters exceed:
(i) a water quality
standard or nondegradation requirement;
(ii) a standard established as a drinking
water maximum contaminant level published in 40 CFR Part 141 ; or
(iii) a risk-based screening level published
in RBCA;
(e) ground water
performance monitoring and natural attenuation data collected in accordance
with U.S. Environmental Protection Agency Office of Solid Waste and Emergency
Response Directive 9200.4-17P indicate that the extent, magnitude, and
concentration of the dissolved contaminant plume have been stable or decreasing
under fluctuating hydrogeologic conditions for a period of monitoring that is
determined by the department to be sufficient to detect unacceptable risks to
human health, safety, or to the environment;
(f) the source area contamination has been
eliminated, controlled, or reduced to the maximum extent practicable, in
accordance with U.S. Environmental Protection Agency Office of Solid Waste and
Emergency Response Directive 9200.4-17P, and any remaining source area
contamination presents a low long-term threat to human health, safety or to the
environment;
(g) documented
investigations demonstrate that taking additional or different cleanup action
is not feasible and will not meet site corrective action objectives within a
reasonable timeframe as compared to monitored natural attenuation;
and
(h) institutional controls are
in place to ensure that identified risks to human health and safety are reduced
to acceptable levels. For the purposes of this rule, institutional controls
must consist of:
(i) deed restrictions or
restrictive covenants that run with the land and that have been approved by the
department and duly recorded;
(ii)
a designated controlled ground water area as provided for in
85-2-506, MCA;
(iii) environmental control easements created
and approved in accordance with
76-7-101 through
76-7-213, MCA; or
(iv) another method approved by the
department that has been shown to ensure that risk to human health has been
reduced to acceptable levels.
(8) If the department categorizes a release
as ground water management, the owner or operator shall monitor ground water in
accordance with a monitoring program developed for the site and approved by the
department.
(a) The monitoring program must
specify the location, frequency, and type of sampling required to evaluate site
conditions and confirm that residual contamination at the site is either
decreasing in extent and concentration or remaining stable.
(b) The frequency of monitoring must not be
less often than one monitoring event every three years.
(c) Monitoring must continue until the
corrective action objectives for the site are achieved and the release may be
categorized as resolved in accordance with (4).
(d) In developing a ground water monitoring
program, the department shall consider:
(i)
the nature, extent, and concentration of the contaminant plume;
(ii) the locations of human health and
environmental receptors relative to the predicted migration path of the
plume;
(iii) historical or
reasonably anticipated land use in the area; and
(iv) any other factors that the department
determines may affect the risk from residual contamination to human health,
safety, or the environment.
(9) If the department categorizes a release
as ground water management, the department shall send a letter to the owner or
operator that:
(a) states that contamination
from the release will be addressed by monitored natural attenuation;
(b) contains the information in (6)(b), (c),
and (e);
(c) states the reasons why
the department believes that the release does not pose an unacceptable present
or future risk to human health, safety, or ecological receptors;
(d) includes a monitoring program that
complies with (8);
(e) includes a
schedule for review of any institutional controls;
(f) states that the release is not
categorized as resolved and documents all conditions that preclude the site
from being categorized as resolved; and
(g) states that the department may require
further remedial investigation or corrective action to determine whether the
requirements in (4) are met if the owner, operator or department proposes to
recategorize the release as resolved.
(10) The department may categorize a release
as resolved with a petroleum mixing zone and send a letter to the owner or
operator in accordance with (11), if the department has determined that
conditions at the site ensure present and long-term protection of human health,
safety, and the environment and that residual petroleum in soil and ground
water will continue to be remediated through natural attenuation processes
without additional intervention, active cleanup, or monitoring. The following
requirements must also be met before a release may be categorized as resolved
with a petroleum mixing zone:
(a) the
petroleum mixing zone is included in a corrective action plan and all the
conditions set forth in
75-11-508, MCA, are met;
(b) documented investigations, conducted in
accordance with ARM 17.56.604, identify the extent or absence of contamination
in the soil, ground water, surface water, or other environmental media;
(c) all free product has been
removed to the maximum extent practicable;
(d) risk evaluations conducted in accordance
with (4)(b) demonstrate that there are no unacceptable risks to human health,
safety, ecological receptors, surface water, or aquatic sediments from exposure
or likely exposure to contamination;
(e) all appropriate corrective actions
associated with the release have been completed and no further corrective
actions are reasonably required by the department;
(f) all applicable environmental laws listed
in (4)(e) associated with the release have been met, except that ground water
quality exceeds a water quality standard for petroleum or petroleum
constituents. In addition, ground water quality may exceed a nondegradation
requirement or a standard established as a drinking water maximum contaminant
level published in 40 CFR Part 141 for petroleum or petroleum constituents;
(g) ground water performance
monitoring indicates that the extent, magnitude, and concentration of the
dissolved contaminant plume have been stable or decreasing under fluctuating
hydrogeologic conditions for a period of monitoring that is determined by the
department to be sufficient to detect unacceptable risks to human health and
safety;
(h) the source area
contamination has been removed to the maximum extent practicable, and any
remaining source area contamination does not pose an unacceptable present or
future risk to human health, safety, or the environment;
(i) at the downgradient boundary of a
petroleum mixing zone, the concentration of any petroleum constituent does not
exceed a water quality standard adopted pursuant to
75-5-301, MCA. The downgradient
boundary of a petroleum mixing zone must be determined by documented
investigations conducted in accordance with ARM 17.56.604;
(j) a petroleum mixing zone must remain
within the facility property boundary unless a recorded easement, a restrictive
covenant, or another institutional control approved by the department on an
adjoining property allows the petroleum mixing zone to extend off the facility
property. For purposes of this rule, the term "facility property" means a
single parcel or contiguous parcels on which one or more petroleum storage
tanks are or were located, provided that contiguous parcels must be under
single ownership at the time the petroleum mixing zone is established;
(k) a petroleum mixing zone may
not extend either beyond 500 feet from the origin of the release or within 500
feet of an existing drinking water well or surface water unless the department
determines, in writing and based on site-specific circumstances, that distances
not meeting the 500-foot criteria, as specified in the determination, will
ensure present and long-term protection of human health and safety and of the
environment in the specific circumstances. In making this determination, the
department shall consider the following factors:
(i) the specific contaminants and
concentrations involved;
(ii) the
nature, hydrogeologic characteristics, and quality of the aquifer(s)
involved;
(iii) the nature and
quality of any well or surface water potentially affected;
(iv) the degree of certainty that
site-specific scientific data supports the determinations made pursuant to (c),
(d), (g), and (h); and
(v) any
other consideration determined by the department to be relevant in the
particular circumstances.
(l) department-approved institutional
controls, engineering controls, or physical conditions are in place to ensure
that identified risks to human health and safety are reduced to acceptable
levels. For the purposes of this rule, institutional controls, engineering
controls, or physical conditions may consist of:
(i) easements, deed restrictions, or
restrictive covenants that run with the land and that have been approved by the
department and duly recorded;
(ii)
a designated controlled ground water area as provided for in
85-2-506, MCA;
(iii) environmental control easements created
and approved in accordance with
76-7-101 through
76-7-213, MCA; and
(iv) an engineering control, physical
condition, or other method or condition approved by the department and designed
to ensure that risk to human health has been reduced to acceptable levels;
and
(m) a notice is
placed on the deed of all parcels of real property on which the facility is
located that the source of the release is resolved with a petroleum mixing
zone. This deed notice must describe the nature and location of the residual
contamination remaining in the soil and ground water at the facility and must
describe all institutional controls, engineering controls, physical conditions,
or other controls or conditions required to maintain the petroleum mixing
zone.
(11) If the
department categorizes a release as resolved with a petroleum mixing zone, the
department shall send a no-further-action letter to the owner or operator. The
letter must describe the following conditions required to maintain the
petroleum mixing zone:
(a) no further
corrective action will be required to address the release provided that all
institutional controls, engineering controls, physical conditions, or other
department-approved controls or conditions are maintained;
(b) residual contamination from the release
will be addressed by natural attenuation processes designed to reduce residual
concentrations of contaminants to levels that meet all applicable environmental
laws, listed in (4)(e), at a point in the future;
(c) all monitoring wells, piezometers, and
other ground water sampling points either be abandoned or maintained by the
owner or operator in accordance with applicable rules and requirements and as
directed by the department. Monitoring well maintenance requirements include
reasonable well maintenance necessary to avoid waste or contamination of ground
water in accordance with Title 37, chapter 43, MCA. Maintenance does not
include monitoring of ground water level, flow, or quality, unless there is a
unique, overriding, site-specific, impact-related reason to require monitoring;
(d) the nature, extent,
concentration, and location of any residual contamination is defined and will
not expand or increase;
(e) the
release does not pose an unacceptable present or future risk to human health,
safety, or ecological receptors;
(f) there be a schedule for review of any
institutional controls;
(g) a
statement that the department may require further documentation of site
conditions to determine whether the requirements in (4) are met if the owner,
operator, or department proposes to recategorize the release as resolved; and
(h) a statement that the
department reserves the right to conduct or to require further investigation or
corrective action if a new release occurs or if the department receives new or
different information related to the release.
(12) Institutional controls, engineering
controls, physical conditions, and notices placed on deeds, required to
categorize a release as resolved with a petroleum mixing zone under (10), may
be removed when the department determines that residual petroleum contamination
in ground water exceeding a parameter listed in (10)(f) is no longer present or
when the release is categorized as resolved in accordance with (4).
AUTH:
75-11-319,
75-11-505, MCA; IMP:
75-11-309,
75-11-505,
MCA