The Department of Environmental Protection (hereafter referred to as the Department), in addition to local and federal agencies, regulates discharges to protect the quality of ground and surface water resources used for drinking water and other purposes. The Underground Injection Control (UIC) Program regulates discharges to "shallow injection wells" (310 CMR 27.00). Injection wells include most subsurface leaching systems (with the exception of septic systems used solely for sanitary waste disposal). Common examples of shallow injection wells in Massachusetts are dry wells, septic systems tied to floor drains in industrial areas, leaching catch basins, and oil/water separators leading to a leaching field. Floor drains themselves are not injection wells; however, they are a common point of entry to subsurface leaching systems which do constitute injection wells.

The discharge of liquid wastes to the environment via shallow injection wells has been a suspected source of contamination in many cases of public drinking water supply closure in Massachusetts. The costs resulting from such contamination are both environmental (permanent or temporary loss of a water supply resource) and financial (the costs of remediating a contaminated water supply and/or developing new sources of water supply). Preventing migration of any contamination emanating from an injection well is much less costly than contamination correction or new water supply development, and serves to protect the environment from long-term or irrevocable damage.

Pursuant to the UIC regulations, where the potential exists for pollutants to enter an injection well (e.g., by means of a floor drain) and where the presence of the pollutants causes, or is likely to cause, a violation of any Massachusetts Drinking Water Regulation, or in the opinion of the Department adversely affects, or is likely to adversely affect, the health of persons, the use of the well is prohibited. With the exception of those discharges authorized under the Department's Ground Water Discharge Permit program, the Department considers this prohibi- tion to include the use of any injection well with an indoor point of entry at facilities which use, store, or otherwise manage hazardous materials and/or wastes (as defined in 310 CMR 30.000 and 310 CMR 40.0000).

In addition to the procedures specified in this document, the owner or operator of a facility where an unauthorized injection well is located must discontinue the unauthorized use of the injection well. The use of an injection well may be discontinued by, for example, sealing the floor drain(s) which lead to it, or connecting the drain(s) to an industrial holding tank (Depart- ment permit required) or a municipal sewer system (Department or administrative entity permit required). For guidance on this process, contact the UIC Program at the address and phone number listed under "Submittals to UIC Program" (section 7.1). Copies of all Department permit applications are available from the Department's Infoline (617-338-2255 or 1-800-462-0444).

This guidance document applies to the closure of all unauthorized shallow injection wells in Massachusetts. All closure procedures should be performed as specified below in this document.

The information contained in this document is intended solely for guidance. This document does not create any substantive or procedural rights, enforceable by any party in any administrative proceeding with the Commonwealth. In addition to summarizing specific requirements, this document also provides guidance on what measures the Department considers acceptable for meeting the general requirements set forth in the regulations. Parties using this guidance should be aware that there may be other acceptable alternatives to this guidance for achieving compliance with such general regulatory requirements.

The regulatory citations provided throughout this document are not meant, and should not be relied upon, to be a complete list of all applicable regulatory requirements.

The purpose of this guidance document is both to outline the components of a shallow injection well closure and to alert the party undertaking the closure of his/her potential responsibilities under MGL c.21E and 310 CMR 40.0000, the Massachusetts Contingency Plan ("MCP", effective 1993 and as revised).

Closure procedures discussed in this document include:

• decommissioning an injection well;
• identifying, excavating, and managing contaminated materials encountered during the closure; and
• conducting confirmatory sampling in the footprint of the excavation.

While undertaking the closure of a shallow injection well, if contamination in soil or groundwater by oil and/or hazardous material (OHM) is encountered, then the provisions of the MCP and guidance provided by Bureau of Waste Site Cleanup (BWSC) policies are applicable. Under the authority of M.G.L. c. 21E, the MCP establishes specific requirements for providing notification to the Department and responding to releases of OHM. These notification requirements, collectively cited as 310 CMR 40.0300, should be reviewed in full by the party proposing to undertake the closure of a shallow injection well prior to doing so. "Assessment only" activities prior to notification under the MCP may be conducted without approval from the Department.

If contamination which constitutes a release of oil and/or hazardous material to the environment and triggers one or more reporting criteria of the MCP is encountered during the assessment activities and/or closure of a shallow injection well, the Department must be notified by the property owner or operator (see "Who Shall Notify" 310 CMR 40.0331) by the applicable deadline (2 Hour, 72 Hour or 120 Day reporting time limits; see 310 CMR 40.0310). In cases where the contamination above reporting thresholds is limited to soil, notification may not be required if a "Limited Removal Action (LRA)" can be properly completed in accordance with 310 CMR 40.0318.

After notification, an Immediate Response Action (IRA) may be required, or a Release Abatement Measure (RAM) may be appropriate. The sections of the MCP which discuss these actions (40.0410 and 40.0440 respectively) should be reviewed thoroughly prior to beginning the closure of the injection well. Like other activities under the MCP, these actions are subject to audit by the Department.

Appendix I summarizes LRAs, IRAs, RAMs, and Comprehensive Response Actions with regard to their applicability to shallow injection well closure.

The MCP requires persons conducting response actions (e.g., IRAs, RAMs, comprehensive response actions) to employ a Licensed Site Professional (LSP) to oversee assessment and cleanup actions and document that such actions are performed in compliance with the MCP. LSPs are experienced professionals in assessment and cleanup activities who are licensed by the Commonwealth. Performance of LRAs does not require the use of an LSP, except as specified under "Excavation and Management of Contaminated Soils" (section 6.3). For a list of LSPs, please contact the LSP Board at 617-292-5794.

All sampling and analyses should be performed in accordance with the MCP. In particular, the provisions of "Environmental Sample Collection and Analyses" (310 CMR 40.0017) and the performance standards at 310 CMR 40.0191 should be followed.

All chemical analyses of samples taken as part of closure and assessment activities should be performed by a laboratory certified by the Commonwealth for the analysis of the contaminants of concern, unless the analytical results provided by the laboratory are accompanied by sufficient QA/QC information to demonstrate the validity of the results.

Procedures noted below in 5.1 and 5.2 should be performed in every case of shallow injection well closure.

5.1 Removal of Existing Sludge\Wastewater:

Prior to performing any other closure procedures outlined in this document, any existing sludge or wastewater from the injection well (e.g., dry well, oil/water separator or MDC trap, septic system, other) should be pumped and disposed of as discussed below.

The Department recommends that a sample of the sludge/wastewater be taken. The results of this sample should be used to pre-characterize the oil and/or hazardous material which may also be present in the environment surrounding the injection well. Sludge/wastewater samples from the injection well should be analyzed for:

• volatile organic compounds (using EPA Method #8240 or 8260);
• total petroleum hydrocarbons (TPH) (using infrared EPA Method #418.1 or a GC/FID methodology);
• total metals (using EPA Methods 7000 series or EPA 6010). Metals analysis may be limited to those metals that could reasonably be expected to be present based on historical use of the facility and/or known discharges to the shallow injection well system;
• other parameters (e.g., PCBs, pesticides) based on specific knowledge of oil and/or hazardous materials used, stored or disposed of at the site, and the site's general history.

As indicated by the results of these analyses, additional testing of the sludge/wastewater may be warranted to determine for disposal purposes whether the material is a hazardous waste under 310 CMR 30.000, the "Massachusetts Hazardous Waste Regulations." Hazardous wastes must be transported by a hazardous waste hauler licensed under M.G.L. c.21C and 310 CMR 30.000. Non-hazardous industrial wastewaters may be taken to a Wastewater Treatment Facility (WWTF). Where required, permission from the WWTF to dispose of the wastewater at the WWTF should be obtained and/or additional testing performed prior to the transport of the wastewater.

5.2 Separators

Where in use, separators (also known and used as oil/water separators, sand traps, gas traps, and MDC traps) should be cleaned (with sludge/wastewater disposed of as noted above in section 5.1). Except in cases where the separator will remain in use (e.g., system connected to sewer line), the structure should either be removed or backfilled with clean fill, sand, or gravel with both the inlet(s) and outlet(s) plugged with a permanent seal.

Procedures outlined in sections 6.1 - 6.4:

• must be performed in cases in which the Department has issued a Notice of Noncom- pliance (NON) or enforcement order specifically requiring these procedures to be performed.
• should be performed as part of remedial actions in cases in which a known release or threat of release (as defined in the MCP) to the environment of OHM has occurred or exists. In these situations, all relevant requirements of the MCP and c.21E must be satisfied.
• are recommended by the Department to be performed as best environmental management practices in all other cases.

6.1 Decommissioning of Injection Well System

After removal of the contents (see "Removal of Existing Sludge/Wastewater" (section 5.1)) of the injection well, the well should be decommissioned according to the following criteria (which correspond to the injection well type). Remedial activities associated with contamination in the impacted leaching media are discussed in "Excavation and Management of Contaminated Soils" (section 6.3).

• Drywells/Cesspools: Excavate and remove underground structure. All inlets to the system must be plugged.
• Septic Systems: Visually inspect tank. Tanks without holes or cracks may be put back into service for sanitary waste only (no industrial or commercial process wastewater should be tied into the septic system). The local Board of Health should be notified in the event that holes and/or cracks are identified in a system. Actions to remove the tank should be coordinated with the local Board of Health.
• Other Systems: Any other injection well system (e.g., non-septic leach fields) should also, depending on the system, either be excavated and removed, or have any and all inlets, and where possible outlets, sealed off.

All excavation holes must be backfilled as noted under "Confirmatory Sampling" (section 6.4.A).

6.2 Samples Proximate to Point of Discharge

A minimum of two soil grab samples should be collected from different locations and analyzed in accordance with the following:

1. Each sample should be collected at or below, and within one foot of, the point of discharge to the ground;
2. Each sample should be screened for "total organic vapors" in headspace using a portable photoionization detector or flame ionization detector as prescribed in Appendix II, "Jar Headspace Analytical Screening Procedure." This data should be expressed as total organic vapor (volatiles) in ppm (v/v) as benzene.
3. The samples should be analyzed as follows:

   VOCs: The sample with the highest headspace reading response should be analyzed for VOCs according to EPA method 8240, or for Halogenated Hydrocarbons via EPA method 8010 or Aromatic Hydrocarbons via EPA method 8020 if the contaminants of concern have been targeted based on the earlier analyses, in accordance with EPA publication Test Methods for Evaluating Solid Waste (EPA/SW 846) or equivalent methods.

   TPH: Each sample should be analyzed for TPH as outlined in Appendix III, "Petroleum Hydrocarbon Analysis."

   OTHER: Each sample should be analyzed for metals and other parameters according to the corresponding criteria noted under "Removal of Existing Sludge\Wastewater" (section 5.1).

6.3 Excavation and Management of Contaminated Soils

If contamination above the applicable MCP cleanup standards is identified in the soils surrounding the injection well, the contaminated soils should then be remediated by soil excavation or other remedial methods.

Excavated contaminated soils should be managed according to the MCP (see 310 CMR 40.0030), the Massachusetts Hazardous Waste regulations (310 CMR 30.000), and related Department Policies. Contaminated soils should be segregated from uncontaminated soils (based on total organic vapor headspace readings and visual/olfactory observations) and stockpiled separately. Soils contaminated with a listed hazardous waste or identified as exhibiting a characteristic of a hazardous waste are subject to the management and disposal requirements of 310 CMR 30.000. All excavated contaminated soil, including that generated as a result of an LRA, should be managed as set forth in 310 CMR 40.0030 and 310 CMR 30.000 in a manner that ensures the protection of health, safety, public welfare, and the environment.

If soil excavation is conducted as part of an LRA, the following limits, as set forth in 310 CMR 40.0318, shall apply:

• Not more than 100 cubic yards of soil contaminated solely by a release of oil or waste oil may be excavated.
• Not more than 20 cubic yards of soil contaminated by a release of hazardous material, or a mixture of oil (or waste oil) and hazardous material may be excavated.
• If groundwater contamination above a reporting threshold is encountered, or if any 2- or 72-Hour reporting criterion is triggered while conducting an LRA, notification to MassDEP is required. Notification is also required if the removal action cannot be accomplished within the LRA volume limits specified above.

If temporary storage of contaminated soil is necessary, stockpiled soil should be placed on, and covered with, a polyethylene tarp (6-mil minimum thickness). Contaminated stockpiles that are to be managed off-site may not remain at the location any longer than 120 days.

Parties performing an LRA should note that, although an LSP is not required to perform the LRA, an LSP must nonetheless be employed if the Bill of Lading soil management process (310 CMR 40.0318(8) and 310 CMR 40.0035(1)(i)) is to be used to manage soils generated by the LRA.

6.4 Confirmatory Sampling

1. Confirmatory Soil Samples

   Once the contaminated soil has been excavated, separate soil grab samples should be taken from the bottom and sides of the excavation to characterize the levels of residual contamination in the remaining "clean" soils and determine whether additional remedial actions may be needed. These samples should be analyzed for the parameters identified by previous analyses.

   Once all contaminated soil is excavated and confirmatory samples taken, the excavation should be backfilled with clean compacted fill. For safety reasons, no hole should be left open or unsecured overnight.

2. Follow Up
   1. If the samples specified immediately above under "A. Confirmatory Soil Samples" do not require notification under the MCP and there is no reason to suspect ground- water contamination at or down-gradient from the injection well, the following items "B.2" and "B.3" may be skipped.
   2. If the confirmatory soil samples specified immediately above in "A" are above the MCP notification threshold, the party undertaking the closure shall notify (if notification has not already occurred) the BWSC in the appropriate MassDEP Regional Office and continue all further remedial activities in accordance with the MCP (see Appendix IV for information on how to contact MassDEP).

      Note: If conducting the cleanup as an LRA and the confirmatory samples indicate further contamination above the reporting threshold in soil, the party may continue to remove soil as an LRA provided the action still falls under the limitations noted in "Excavation and Management of Contaminated Soils" (section 6.3). If the activity cannot be concluded under the constraints of the LRA, then the party must notify the Department under the "120 Day" notification requirements. Excavation may be continued as a RAM with MassDEP's approval.

   3. If there is reason to suspect groundwater contamination at or down-gradient from the injection well, the party undertaking the closure should conduct further sampling (e.g., install monitoring wells). If groundwater contamination above applicable reportable concentrations is confirmed, the party must notify (if notification has not already occurred) the Department's BWSC accordingly and continue all further remedial activities in accordance with the MCP.

7.1 Submittals to UIC Program:

• Upon completion of the injection well closure, complete a UIC Notification Form (PDF) (19 KB) and submit it to the UIC program at the address below. This form will establish the date of closure of a shallow injection well for your own and the Department's records.
• In cases where soil sampling and associated activities are required due to the issuance of an enforcement order from the Department's UIC program, the following must also be submitted to the UIC program:
• a site plan with locations of floor drains, treatment systems (separators, septic systems, etc.), points of discharge to the ground, screening and sampling locations, the boundaries of the excavated area; and
  
• screening and analytical results.

Submittals to the UIC program should be made at the following address:
MassDEP/Division of Water Supply
Underground Injection Control Program
One Winter Street, 5th floor
Boston, MA 02108
(617-292-5770)

Copies should also be sent to:
Local Board of Health
Local Water Department

7.2 Submittals to BWSC and Record Retention:

Documentation associated with the closure of a shallow injection well should be submitted and/or retained as specified in Appendix I, section B.

Submittals to the Bureau of Waste Site Cleanup should be made at the appropriate Department regional office. Appendix IV is a list of Massachusetts cities and towns (indexed by regional jurisdictions) which provides the address and telephone numbers for the four regional offices and Boston.

All submittal forms and BWSC policies are available from the "MCP Hotline" through the Department's InfoLine (617-338-2255 or 1-800-462-0444). Computer/modem access to BWSC policies and regulations can be obtained by dialing 617-292-5546.

1. Response Actions Under the MCP
   Web page
2. Jar Headspace Analytical Screening Procedure
3. Petroleum Hydrocarbon Analysis
4. MassDEP Regional Phone #s and List of MA Cities and Towns by Region
5. UIC Notification  (PDF 19 KB)
6. Q & A Summary for the Non-Technical Reader
   Web page