Nebraska Administrative Code › Topic - ENVIRONMENT AND ENERGY › Title 118 - GROUND WATER QUALITY STANDARDS AND USE CLASSIFICATION › Appendix B - REMEDIAL ACTION PROTOCOL FOR PETROLEUM RELEASES

Current through June 17, 2024
Procedures for Determining Needed Action for Point Source Pollution
	 Events from Petroleum Releases Using Risk-Based Corrective Action
	 (RBCA).
If not already known, the Department will identify, if possible, the
	 source(s) of contamination and the responsible party (or parties). The
	 Department will notify the responsible party after the determination has been
	 made. A responsible party is to complete the following protocol in accordance
	 with Chapter 6, 002.
Part I. IMMEDIATE ACTION
Step 1. Initial Review
1) Perform an initial review to determine whether immediate action is
	 needed to eliminate the existence or likelihood of an imminent and substantial
	 threat to the public health and welfare or the environment or to mitigate the
	 significantly increasing difficulty of cleanup if action is delayed, and if so,
	 what actions are required. Base the review on as many of the items addressed in
	 Step 6 as possible.
a) imminent - a short time span (i.e., less than 90 days)
b) substantial - a significant impact on the public or environment
	 (e.g., human illness or death, serious financial loss, severe ecological
	 damage)
c) significant - if action delayed, cleanup costs increase by one or
	 two orders of magnitude
d) Immediate actions - may include cleanup to at least an initial
	 level, stabilization or containment, monitoring, shutdown/termination of
	 facility/activity, or any combination of measures. These actions are carried
	 out by the responsible party.
2) If the need for immediate action is apparent or if the need cannot
	 be readily determined, proceed to Step 2 and work in conjunction with
	 Department.
3) If no immediate action is necessary (e.g., due to the nature of the
	 pollution event developing over many years or moving slowly), proceed to Step
	 4.
Step 2. Implementation of Immediate Actions
1) Implement the immediate actions identified as required by Step 1 or
	 as determined necessary in consultation with the Department.
Proceed to Step 3 when the immediate actions have been
	 completed.
Step 3. Evaluation of Immediate Actions
1) Determine if immediate action has been successfully eliminated the
	 imminent and substantial threat to the public health and welfare and the
	 environment or successfully mitigated any significant increase in difficulty of
	 cleanup associated with delayed action.
2) If the immediate action was unsuccessful, return to Steps 1 and
	 2.
3) If requirements were met, proceed to Step 4.
Step 4. No Immediate Threat Present
Immediate action is not now needed, but additional measures for
	 complete and permanent resolution of the problem may be required. Further
	 assessment is necessary to determine the need for any final remedial
	 action.
Proceed to Part II, Step 5.
Part II. FINAL REMEDIAL ACTION
If at any time during the Part II assessment an immediate threat is
	 identified, return to Step 1 (Part I).
Step 5. Preliminary Assessment
1) Complete a preliminary assessment to evaluate the possible threat of
	 contamination to soils and ground water and threat to public health and
	 welfare. This assessment involve s a review of existing information and require
	 the collection of minimal or no field data. If it can be determined by the
	 Department from this preliminary assessment that there is limited soil
	 contamination and no threat of ground water contamination or threat to human
	 health and welfare, proceed to Step 12. If soil contamination is extensive or
	 its extent is unknown or ground water contamination is possible or likely,
	 proceed to Step 6.
Step 6. RBCA Tier 1 Site Assessment
1) Before this or any subsequent assessments are started, contact the
	 Department to establish what information must be collected. The Department will
	 specify sampling and analysis requirements.
2) Collect all information, including any site assessment data, as
	 directed by the Department. The required site assessment data will include, but
	 not be limited to, the following types of information:
1. historical information;
2. site information;
3. contamination characteristics;
4. aquifer characteristics.
3) Investigate Tthe following potential exposure pathways are to be
	 investigatedfor chemicals of concern designated by the Department:
1. Dermal contact with and ingestion of chemicals of concern from
	 contaminated surface soils;
2. Enclosed space inhalation of chemicals of concern from contaminated
	 subsurface soils;
3. Leaching of chemicals of concern from contaminated surface and
	 subsurface soils to ground water;
4. Enclosed space inhalation of chemicals of concern from
	 contaminated, shallow ground water; and,
5. Ingestion of chemicals of concern from contaminated ground
	 water.
Individual chemicals of concern are designated based on the petroleum
	 product(s) released at the site and include, but are not limited to, the
	 following:
Light Distillates (e.g., gasoline,
				  JP-4)
Benzene
Total Xylenes
Toluene
n-Hexane
Ethylbenzene
Methyl tertiary-Butyl Ether (MTBE)
Middle Distillates (e.g., diesel fuel,
				  kerosene)
Benzene
Naphthalene
Toluene
Pyrene
Ethylbenzene
Benzo(a)pyrene (BaP)
Total Xylenes
Waste Oil
Benzene
Naphthalene
Chlorinated
				solvents*
Toluene
Pyrene
Metals*
Ethylbenzene
BaP
Ethylene glycol*
Total Xylenes
To be determined on a case-by-case basis as directed by the Department.
	 The Department will provide investigative and sampling requirements for these
	 chemicals as needed.
4) Report the required information to the Department in the format
	 specified by the Department.
Step 7. Evaluation of RBCA Tier 1 Investigation
	 Results
In evaluating the RBCA Tier 1 investigation results, the contamination
	 levels found during the site investigation will be compared to risk-based
	 screening levels (RBSLs) which will be established by the Department using the
	 following criteria:
1. Remedial Action Classifications.
A remedial action class (RAC) is defined for pollution events in three
	 types of ground water (or overlying soils) depending on the degree (or
	 potential) of use of the ground water as drinking water. The extent of remedial
	 action recommended will differ depending on the RAC of the contaminated (or
	 likely to be contaminated) ground water. The RAC assigned will be determined
	 from the condition of the ground water prior to the pollution event. The
	 Department will assign the RAC based on information submitted by the
	 responsible party in the RBCA Tier 1 site assessment and other available
	 information.
RAC-1 This category includes ground waters of Class GA and the portion
	 of Class GB in a 500-foot radius (or greater, if determined necessary by the
	 Department) around all private drinking water supply wells. RAC-1 is
	 automatically assigned anytime a public or private drinking water supply well
	 has been polluted.
RAC-2. This category includes ground waters of Class GB (except for the
	 portion of Class GB placed in RAC-1) and Class GC(R).
RAC-3. This category includes, but is not limited to, ground waters of
	 Class GC (except for Class GC(R) which was placed in RAC-2).
The RAC categories are not intended to represent a ground water
	 classification system but rather a pollution event ranking scheme. It gives the
	 Department a method to determine the importance of remedial action based on the
	 use of the ground water. For instance RAC-1 is the category of highest rank; it
	 represents that ground water actually being used for drinking water and that
	 ground water intended to be used in a public drinking water supply. Therefore,
	 RAC-1 events will normally receive the most extensive remedial action
	 measures.
RAC-2 events involve ground water not now directly used as drinking
	 water but having a reasonable potential to be used in the future. The potential
	 for use exists if the ground water is located in a highly populated area or is
	 part of a regional, high-yielding aquifer or if otherwise justified. The RAC-2
	 category also includes ground water with prior contamination that may be easily
	 or cost-effectively treated to drinking water quality.
Pollution events will be of lowest importance, RAC-3, if the ground
	 water involved is not used, or likely to be used, as drinking water. Generally
	 remedial action measures will be least extensive for this category since the
	 future use of ground water for drinking is improbable. Justification for
	 assigning events to RAC-3 will be based on a combination of several different
	 reasons. One reason for unusability is poor natural quality which makes the
	 ground water unfit for human consumption. Insufficient yield is another reason
	 the ground water may not be used for drinking. A third reason is historical
	 contamination that occurred prior to the pollution event currently being
	 investigated (see NRS §
								81-1505(2)(d)).
	 This past contamination may have rendered ground water unsuitable for drinking
	 and uneconomical to treat. Past and present intensive land use is also a reason
	 why ground water could be unusable as drinking water. This includes areas of
	 concentrated industrial development or densely populated areas where ground
	 water is likely to be contaminated or will not be used as drinking
	 water.
The ranking of some events as RAC-3 does not mean there will be places
	 in the State where wholesale contamination of ground water will be allowed.
	 Departmental authority through its various programs to control practices or
	 discharges that may contaminate ground water will still be in effect. RAC-3
	 occurrences, in general, will be given a lower priority and less staff effort
	 by the Department than RAC-1 or RAC-2 occurrences; however, cleanup of a RAC-3
	 event may be required due to concerns about enclosed space inhalation exposure
	 pathways and vapors threatening public health and welfare.
RACs were developed primarily for use with the principal aquifer--the
	 ground water commonly used for drinking. They will also be adapted for use with
	 both deeper and perched ground water. When doing so, interconnections with
	 overlying or underlying ground water of different quality will be
	 considered.
Some contamination threats may occur in which the use potential of the
	 ground water would be RAC-1 or RAC-2, but the soil, geology, and other
	 site-specific characteristics are such that ground water contamination is
	 virtually impossible. After an appropriate assessment, the event may be
	 downgraded to RAC-3.
In every ground water contamination occurrence, certain minimum
	 requirements will be imposed upon the responsible party, depending on the RAC.
	 Cleanup of readily removable contaminants (e.g., free product) will be
	 required. Additional cleanup and/or mitigation may also be required. If
	 additional cleanup is not required, the remaining contaminated ground water
	 will be managed and monitored to prevent any further damage.
In RAC-3, cleanup of readily removable contaminants (e.g., free
	 product) will be required. Additional cleanup of a RAC-3 event may be required
	 due to concerns about enclosed space inhalation exposure pathways and public
	 health and welfare. Monitoring may also be necessary. Because RAC-3 ground
	 water is generally not used for drinking water, the ground water ingestion and
	 soil leaching to ground water pathways are considered to be incomplete in RAC-3
	 and not subject to this RBCA assessment.
2. Carcinogenic and non-carcinogenic health effects.
A. Carcinogenic effects
Chemical-specific Maximum Contaminant Levels (MCLs) (see Chapter 3)
	 will be used to calculate the appropriate RBSL for a carcinogen for the
	 groundwater ingestion and soil-leaching to groundwater exposure pathways of
	 concern for a RAC-1 release.
An Excess Lifetime Cancer Risk (ELCR) of
	 1x10-6 will be used in the calculation of the RBSLs
	 for a carcinogen for the dermal contact/soil ingestion exposure pathway and for
	 inhalation pathways in the presence of subsurface structures for all
	 releases.
An ELCR of 1x10-5 will be used in the
	 calculation of the RBSLs for a carcinogen for the groundwater ingestion and
	 soil-leaching to groundwater exposure pathways of concern for a RAC-2 release
	 and for the inhalation exposure pathways when no subsurface structures are
	 present for all releases.
B. Non-carcinogenic effects
Chemical-specific MCLs (or a health-based standard where an MCL has
	 not been promulgated for a particular chemical) will be used to calculate the
	 RBSL for a non-carcinogen for the groundwater ingestion and soil-leaching to
	 groundwater exposure pathways of concern for a RAC-1 release.
RBSLs for non-carcinogens for the groundwater ingestion and
	 soil-leaching to groundwater exposure pathways of concern for a RAC-2 release,
	 for the dermal contact/soil ingestion exposure pathway for all releases, and
	 for the enclosed space inhalation pathways for all releases will be established
	 by the Department using the following criteria:
1. exposure pathway;
2. RAC designation;
3. level of exposure based on the ratio of the observed concentration
	 of a chemical of concern to a chemical-specific reference concentration.
For purposes of the RBCA Tier 1 assessment, toluene, ethylbenzene and
	 total xylenes are considered to have additive health effects.
3. Fate and transport models. The Department will select various models
	 and model default values to calculate RBSLs for use in evaluating the RBCA Tier
	 1 data.
4. Land use.
5. Location of water supply wells.
6. Other criteria as determined by the Department.
Upon comparing the RBSLs to the actual contamination levels found
	 during the site investigation and consideration of other pertinent factors, the
	 Department will determine if additional remedial actions will be required. If
	 additional remedial actions are not required, proceed to Step 11. Otherwise,
	 proceed to Step 8.
Step 8. RBCA Tier 2 Site Assessment
1) Perform a RBCA Tier 2 site assessment for those exposure pathways
	 where actual site contamination levels were greater than the Tier 1 RBSLs under
	 Step 7. This investigation will define the extent of contamination from the
	 release and collect site-specific parameters to use in the Tier 2 evaluation
	 performed under Step 9. The Department will specify what data needs to be
	 collected for the Tier 2 site assessment. Work will be approved by the
	 Department prior to beginning the investigation.
2) Report the results of the Tier 2 site assessment in the format
	 specified by the Department. The Department may, at any time, request
	 additional information.
Step 9. Evaluation of RBCA Tier 2 Investigation Results,
	 Determination of Site-Specific Target Limits, and Review of Proposed Remedial
	 Actions
The site-specific physical and chemical assessment found during the
	 Tier 2 site assessment will be used to establish site-specific target limits
	 (SSTLs) using the same fate and transport models previously used to establish
	 the RBCA Tier 1 RBSLs. The contamination levels found during the investigation
	 will be compared to the SSTLs in a manner similar to that performed for the
	 RBCA Tier 1 evaluation.
1) The Department will determine if additional remedial actions will be
	 required. If additional remedial actions are not required, proceed to Step
	 11.
2) The Department will set a preliminary cleanup level for any
	 additional cleanup required. The level will normally be set at the appropriate
	 SSTL(s).
After receiving notification of the preliminary cleanup level, either
	 agree or propose an alternate level. If a different cleanup level is proposed,
	 it must be based on a technological, risk, or economic analysis. The Department
	 may also propose an alternate level.
a) A technological analysis will determine if technologies exist to
	 clean up the soil and/or ground water to the preliminary cleanup level. If
	 cleanup to the preliminary level is not technologically possible, report what
	 level of cleanup is attainable. As part of this analysis, the technological
	 feasibility of various mitigative actions (e.g., supplying new sources of water
	 and point-of-use treatment) should be investigated.
b) A risk analysis may include other factors, information, or
	 evaluations not previously considered. Other ELCR target levels may be
	 considered if appropriate.
c) For an economic analysis, examine the economics of cleaning up to
	 the preliminary level. If it is impossible to reach the preliminary cleanup
	 level, report what level of cleanup is economically possible. The economic
	 feasibility of mitigation instead of cleanup should also be analyzed.
If cleanup to the preliminary level is not attainable based on one or
	 more of the foregoing analyses, report what portion of the soil and/or ground
	 water will remain contaminated following a lesser degree of cleanup. Given the
	 technological considerations of cleanup, the appropriate calculations should be
	 used in an attempt to define the three-dimensional boundary of the
	 contamination plume under different remedial action scenarios (including no
	 cleanup). The contamination plume, in this case, is defined as soil and/or
	 ground water where the concentrations of identified contaminants exceed their
	 preliminary cleanup levels. For every cleanup scenario assessed, the economic
	 impacts are to be defined. The relationship of the contaminated media (i.e.,
	 ground water, soils, soil gas) boundaries to existing users and potential
	 points of exposure must be described.
If submitting an alternative cleanup level, include any supporting
	 justification for an alternate cleanup level, a contamination maintenance
	 program, a mitigation plan, or combination. The Department will consider the
	 information contained in the justification on a case-by-case basis and
	 establish a proposed final cleanup level or action. The level may be the same
	 as the Department's preliminary cleanup level, the same as the proposed
	 alternate cleanup level, or some other level.
The Department's decision on the remedial action necessary, including
	 the proposed final cleanup level, will be placed on public notice. Any person
	 may submit written comments on the proposed action or may request a
	 hearing.
Following the comment period and any hearing the Department will notify
	 the responsible party of Department's final decision (including changes made as
	 a result of a hearing).
3) Develop a workplan and schedule for performance of the final
	 remedial action. The time frame for required action (including cleanup) will be
	 the period of potential exposure to the contamination in the absence of any
	 remedial action or 20 years, whichever is less. On a case-by-case basis, a
	 longer period of time may be allowed if adequately justified by the responsible
	 party. The workplan is subject to the Department's approval.
Step 10. Implementation and Review of Remedial
	 Actions
1) Obtain any other permits from the Department that may be required to
	 implement the workplan (e.g., UIC, NPDES).
2) Implement the remedial actions approved in the workplan.
3) Keep the Department apprised of cleanup efforts, and the Department
	 will periodically review the effectiveness of the remedial actions. If the
	 Department determines the long-term needs of protecting the public health and
	 welfare and the environment have not been, or are not being, satisfied or if
	 additional remedial action is necessary, the Department may require a return to
	 Steps 8 and 9.
4) A request may be made to modify the required final remedial action
	 during the implementation process. Any request must be accompanied by
	 additional justification as described in Step 9. The Department may propose
	 modifications to the required final remedial action. If a change is
	 appropriate, a public notice will be issued.
Step 11. Final Review
A final review will be performed by the Department to determine the
	 need for any ongoing actions. These may include long-term monitoring to ensure
	 cleanup levels are stabilized and maintained, periodic sampling of nearby
	 supply wells, maintenance of installed structures, and annual case review. If
	 established cleanup levels were never reached, ongoing monitoring or
	 maintenance may be necessary to ensure other soil and/or ground water does not
	 become contaminated and/or public health and welfare threats do not
	 exist.
1) Continue any ongoing actions determined to be necessary by the
	 Department until ground water and soil contamination is no longer a
	 concern.
Step 12. Closure
The situation does not pose a threat to ground water quality or public
	 health and welfare.