§ 35-11-1605 — Voluntary remediation standards; site- specific, risk-based standards; considerations in choice of remedy; alternate standards for soil; alternate standards for soil or water; point of compliance; contamination from source not on site; alternate remediation standards for site contaminated from source not on site; supplemental requirements

(a) Consistent with any requirements necessary to retain
state primacy in federal programs, any remedy proposed by an
owner of an eligible site, or considered by the director, shall:
(i) Be protective of human health, safety and the
environment. A remedy shall be considered to be protective of
human health if it reduces risk to human receptors of acute and
chronic toxic exposures to contaminants to levels that do not
pose a significant risk to human health. A remedy shall be
considered to be protective of the environment if it adequately
reduces risk of significant adverse impacts to ecological
receptors for which habitats have been identified on or near the
site. Remedies may meet this requirement through a combination
of monitored natural attenuation, removal, treatment, or
engineering or institutional controls. Except as provided in
subsection (d) of this section, any site where a remedy is
proposed that includes engineering or institutional controls
must also have been designated as a use control area in accord
with W.S. 35-11-1609;
(ii) Attain standards established by the director
under this subsection for air, soil, and water affected by the
site, unless the director sets an alternate standard in accord
with subsection (c) or (d) of this section. No standard set
under this section for a contaminant shall be set at a level or
concentration lower than the background level or concentration
for that contaminant. A remedy must attain standards or
alternate standards by the end of the remediation period set
forth in the remedy agreement. A remedy shall be considered to
attain standards for air, soil and water if it:
(A) Meets any applicable media standards
established under federal or state law or rule or regulation; or
(B) Meets site-specific, risk-based standards
developed for the eligible site. Site-specific, risk-based
standards shall establish a risk reduction goal for contaminants
which are known or suspected carcinogens to ensure that the
excess upper bound lifetime cancer risk to any exposed
individual may not exceed a probability of developing cancer of
one in one million (1 in 1,000,000) to one in ten thousand (1 in
10,000). The one in one million (1 in 1,000,000) risk level
shall be used as the point of departure for determining
remediation goals for alternatives when individual contaminant
standards are not available, or are not sufficiently protective
because of the presence of multiple contaminants at a site or
multiple pathways of exposures. Site-specific, risk-based
standards must also require that for contaminants which are
systemic toxicants, the hazard index must not exceed one (1).
The director shall use residential exposure factors, giving
consideration to children and the elderly, to establish site-
specific, risk-based standards under this subsection for soils
and air. The exposure factors to be used by the director to
establish site-specific, risk-based standards under this
subsection for hazardous substances in groundwater shall assume
that groundwater may be used as a drinking water source,
provided that no standard set under this subsection for a
contaminant shall be set at a level or concentration lower than
the background level or concentration for that contaminant. For
nonhazardous substances, the exposure factors to be used by the
director shall assume uses consistent with the class of use
prior to contamination of the groundwater.
(iii) Control any sources of releases so as to reduce
or eliminate, to the extent technically practicable, further
releases as required to protect human health and the
environment. A remedy shall be considered to control sources of
releases if it controls the release of contaminants from sources
to any media in concentrations that exceed applicable standards
set by the director under paragraph (a)(ii) of this section, or
the soil standards under subsection (c) or (d) of this section;
and
(iv) Comply with any applicable standard for
management of wastes generated as a consequence of the remedy. A
remedy shall be considered to comply with applicable standards
for management of wastes if all wastes generated as a
consequence of implementation of the remedy are treated, stored
or disposed of in compliance with the requirements of this act.
(b) The director shall choose a remedy, or combination of
remedies, from among those remedies which meet the requirements
of subsection (a), (c) or (d) of this section, as applicable. In
choosing a remedy, the director shall consider:
(i) The extent to which the remedy will be reliable
and effective for the long term. For remedies that include
engineering or institutional controls in accord with a use
control area designation, the director shall consider the
expected life cycle performance of any engineering controls,
monitoring systems and institutional controls;
(ii) The extent to which the remedy results in a
reduction of toxicity, mobility or volume of contaminants. The
director shall consider the degree to which remedies incorporate
treatment or removal of contaminants to lower long term risk to
human health and the environment;
(iii) The short term effectiveness of the remedy.
The director shall consider the time required for each remedy to
attain standards for air, soil and water specified in paragraph
(a)(ii) or subsection (c) or (d) of this section, as applicable.
A remedy involving monitored natural attenuation may be
considered whether or not the director has made a determination
of technical impracticability under subsection (d) of this
section. Monitored natural attenuation shall be deemed effective
if there is evidence that natural attenuation is occurring and
will be completed within a reasonable time period;
(iv) Impacts which may be caused by implementation of
the remedy. The director shall consider any adverse impacts
which may be caused by a remedy, and shall take into
consideration the gravity of any projected impact and the cost
and availability of measures to mitigate the impact;
(v) The extent and nature of contamination and
practicable capabilities of remedial technologies, and whether
achieving standards is technically impracticable;
(vi) Reasonably anticipated future land uses or use
restrictions in a use control area designation;
(vii) Consistency of remedies with the nature and
complexities of releases of contaminants; and
(viii) Cost of the remedy. The director shall
consider whether a remedy presents a substantial and
disproportionately high cost for implementation and completion.
The director shall compare the costs of remedies considering the
degree of risk reduction that is afforded by each remedy. Costs
considered shall include capital, operation and maintenance,
engineering and institutional control costs and monitoring costs
for the anticipated life of the remedy.
(c) The director may establish alternate site-specific,
risk-based standards for surface and subsurface soils to be
employed at a site in lieu of the soil standards in paragraph
(a)(ii) of this section, for any site that is located within a
use control area designated under W.S. 35-11-1609. A remedy that
employs alternate standards established by the director under
this subsection shall meet the requirements of this subsection
and paragraphs (a)(i), (iii) and (iv) of this section. The
alternate standards for such a site shall use the carcinogenic
and systemic toxicant risk reduction goals of subparagraph
(a)(ii)(B) of this section, except that the exposure assumptions
used to calculate the alternate standards under this subsection
shall be consistent with the use restrictions contained in the
use control area designation. If the director establishes
alternate soil standards under this subsection, the owner or
operator must evaluate technologies that can meet the alternate
soil standards. Owners or operators of eligible sites that
implement remedies which achieve the alternate soil standards
set under this subsection may be issued a certificate of
completion and covenant not to sue pursuant to W.S. 35-11-1607.
The soil standards of paragraph (a)(ii) of this section must be
met if the owner or operator applies to remove the use
restrictions applicable to the site or to receive a no further
action letter under W.S. 35-11-1608.
(d) The director may establish alternate site-specific,
risk-based standards for soil or water to be employed at a site
in lieu of the soil and water standards in paragraph (a)(ii) of
this section if, after evaluation of currently available
technology the director determines that it is technically
impracticable to meet a standard at a specific site. A remedy
that employs alternate standards established by the director
under this subsection shall meet the requirements of this
subsection and paragraphs (a)(i), (iii) and (iv) of this
section. The technical impracticability determination shall
include evaluation of the cost of remedy alternatives, including
but not limited to, substantial and disproportionately high
costs, present worth of construction, operation and maintenance
costs, continued operational costs of the remedy selected and
costs of any proposed alternative remedy strategies. Whenever
the director sets an alternate standard, the director shall
select a remedy capable of meeting the alternate standard and
which is technically practicable, controls any sources of
contamination to the extent technically practicable, and
controls human and environmental exposures to contaminated air,
soil or water. The director may establish alternate standards
for soil or water under this subsection only if the owner has or
obtains rights to control human or environmental exposures to
contaminated media, and consents to impose such controls as are
required to protect human health and the environment.
Notwithstanding the provisions of paragraph (a)(i) of this
section, or W.S. 35-11-1609 such controls may be imposed by the
owner without the site receiving a use control area designation
under W.S. 35-11-1609. The standards of paragraph (a)(ii) of
this section must be met if the owner or operator applies to
remove the use restrictions applicable to the site or to receive
a no further action letter under W.S. 35-11-1608.
(e) When establishing standards under paragraph (a)(ii) or
subsection (c) or (d) of this section, the director shall
specify one (1) or more points of compliance where standards
must be achieved. In specifying a point of compliance, the
director shall consider the following factors:
(i) Compliance with groundwater standards shall be
monitored as close as reasonably practical to the contaminant
source or site boundary or boundary of the use control area. The
director shall select any groundwater point of compliance based
upon the evaluation of the properties of the aquifer, the
proximity of existing and reasonably anticipated points of
groundwater withdrawal or discharge to the surface, the location
of the contaminant plume relative to the site or use control
area boundary, the toxicity of the contaminant, the presence and
proximity of multiple contaminant sources, the exposure and
likelihood of actual exposure to contaminated groundwater, and
the technical practicability of groundwater remediation;
(ii) For soils, standards shall be met at locations
determined to ensure protection of human health and identified
environmental receptors, and protection of surface water,
groundwater and air resulting from any potential transfer of
contaminants from soils to these other media; and
(iii) For surface water, standards shall be met at
the point where any release enters any surface water of the
state consistent with applicable federal and state requirements.
If sediments are affected by releases to surface water, a
sediment point of compliance may also be established.
(f) Remediation standards for a site that has become
contaminated by a release or migration of contamination from a
source not located on the site shall be appropriate for any use
control area designation applicable to such site, or if desired
by the owner the remediation requirements shall be adequate to
restore the site to all uses for which it was suitable prior to
the contamination.
(g) The department may establish supplemental requirements
for owners or operators of lands or facilities subject to
permitting or corrective action requirements of the hazardous
waste rules and regulations promulgated under W.S. 35-11-503(d)
as may be necessary to ensure that such sites are characterized
and remediated in a manner which is consistent with, equivalent
to, and no less stringent [than] permitting, closure, post-
closure and corrective action requirements contained in rules
and regulations adopted by the United States Environmental
Protection Agency (EPA) under authority of subtitle C of the
Resource Conservation and Recovery Act, 42 U.S.C. § 6901, et
seq. Election by an eligible site owner or operator who is
subject to such hazardous waste permitting or corrective action
requirements to participate in the voluntary remediation program
under this article shall not relieve the owner or operator of
the duty to comply with all requirements of the hazardous waste
rules and regulations promulgated under W.S. 35-11-503(d).