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                  TABLE OP CONTENTS  (Continued)



                                                          Page




      10. Issue:  Definition of Liner                      82



      11. New Definitions                                  $3



V.    References                                           84



VI.   Appendix  - Final Regulatory  Language                 86

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 I.    INTRODUCTION




A.    Purpose and Scope




      Under the authority in Subtitle C of the Resource  Conservation




and Recovery Act of 1976, EPA is promulgating .interim status




standards for storage, treatment, and disposal of hazardous waste




in surface impoundments.




      Draft regulations on this subject were proposed for  public




comment on December 18, 1978.  Comments were received by the




Agency at public hearings and in writing.  This document provides




the rationale for the regulations and responds to the comments




received.




      This document is divided into four parts, followed by




references and appendices.  Part I, Introduction, describes the




purpose and scope of this document, the legislative authority for




the regulations, and key definitions used in their development.




Part II,  Need for Regulation, explains the basic public health




and environmental problems which show the need for regulation in




this area.  Part III,  Synopsis of the Proposed Regulations,



summarizes the proposed regulations.  Part IV, Analysis of Issues,




comprises the bulk of this document.  For each issue, it discusses



the proposed regulation and its rationale, comments received,




and the Agency's response, including any new information obtained,




and the final regulatory language.



B.    RCRA Mandate for the Regulation




      Section 3004 of Subtitle C requires EPA to promulgate




regulations establishing standards, applicable to owners and




operators of hazardous waste treatment,  storage,  and disposal




facilities, as may be necessary to protect human health






                                  1

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and the environment.  Section 3004 further  requires that  such



standards include requirements respecting   (1) the location,



design, construction, and operation of  such hazardous waste



treatment, storage, or disposal  facilities,  (2) records of



hazardous wastes treated, stored, or disposed, and (3) reporting,



monitoring; and inspection.  Surface impoundments are common



means of treating, storing,, or  disposing of hazardous wastes,



and are covered by Section  3004.



      Section 3005 (e) also provides a  period of interim  status



for owners and operators of existing facilities for treatment,



storage, and disposal of hazardous wastes.   After the effective



date of the regulations, treatment, storage,  and disposal may not



be carried out except in accordance with a  permit issued  under



Section 3005.  However, persons  who have applied for a permit and



who  have notified  EPA of their activities,  have interim status



and are treated as though a permit had  been issued.  Interim



status thus applies between the  effective date of treatment,



storage, and disposal regulations and the date on which a permit



is issued or denied to a particular owner or operator.



      A complete rationale  for establishing interim status



standards and responses to  the public comments on that subject



are presented in the preamble to the Parts  264 and 265 regulations



and  in the background document entitled "General Issues Regarding



Interim Status Standards ."



      This background document on interim status standards for



surface impoundments addresses the specific standards applicable



to surface impoundments during the time a facility has interim




status.

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C.    Definitions




      Key definitions pertinent to the surface impoundment




regulation are:




      (1)  "Dike"* means an embankment, or ridge of either natural




           or man-made materials used to prevent the movement of




           liquids, sludges, solids, or other materials.




      (2)  "Disposal" means the discharge, deposit, injection,




           dumping, spilling, leaking or placing of any solid




           waste or hazardous  waste into or on any land or water




           so that such solid waste or hazardous waste or any




           constituent thereof may enter the environment or be



           emitted into the air or discharged into any waters,




           including ground waters.




      (3)  "Disposal Facility"** means a facility or part of a




           facility at which hazardous waste is intentionally




           placed into or on any land or water, and at which




           wastes will remain after closure.




      (4)  "Facility"** means all contiguous land, structures,




           other appurtenances, and improvements on the land,




           used for treating, storing, or disposing of hazardous



           waste.  A facility may consist of several treatment,




           storage, or disposal operational units (e.g. one or




           more landfills,  surface impoundments or combinations




           of them.)
 *New definition, see rationale in Part IV of this document.

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      (5)   "Freeboard"* means the vertical distance between the

           top of a tank or surface impoundment dike,  and the

           surface of the waste contained therein.

      (6)   "Ground Water"** means water below the land surface in

           a zone of saturation.

      (7)   "Incompatible waste"** means a hazardous waste which

           is unsuitable for:

           (i)   Placement in a particular device or facility

                 because it may cause corrosion or decay of

                 containment materials (e.g., container inner liners

                 or tank walls); or

           (ii)  Commingling with another waste or material under

                 uncontrolled conditions because the commingling

                 might produce heat or pressure, fire or explosion,

                 violent reaction, toxic dusts, mists, fumes, or

                 gases, or flammable fumes or gases.

      (8)   "Injection well" means a bored, drilled, or driven

           well; or a dug well, where the depth of the dug well is

           greater than the largest surface dimensions.

      (9)  "Operator"** means any person who is responsible for

           the overall operation of a facility.

      (10) "Owner"** means any person who owns a facility or

           portion of a facility.
* Revised definition, see rationale in Part IV of this document.
**Revised definition, see background document on definitions.

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     (11)  "Storage"** means the holding of hazardous waste for a

          temporary period, at the end of which the hazardous

          waste is treated, disposed of, or stored elsewhere.

     (12)  "Surface Impoundments"* or "impoundment" means a

          facility or part of a facility which is a natural

          topographic depression, man-made excavation,  or diked

          area formed primarily of earthen materials (although

          it may be lined with man-made materials), which is

          designed to hold an accumulation of liquid wastes or

          wastes containing free liquids, and which is  not an

          injection well.  Examples of surface impoundments are

          holding, storage, settling,, and aeration pits, ponds,

          and lagoons.

     (13)  "Treatment"** means any method, technique, or process,

          including neutralization, designed to change  the

          physical, chemical, or biological character or

          composition of any hazardous waste so as to neutralize

          such waste, or so as to recover energy or material

          resources from the waste, or so as to render  such

          waste non-hazardous, or less hazardous; safer to

          transport, store, or dispose of; or amenable  for

          recovery, amenable for storage, or reduced in volume.
 *Revised definition, see rationale in Part IV of this document.
**Revised definition, see background document on definitions.

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II.   NEED FOR REGULATION



A.    Potential for Damage



      In 1978, EPA published a preliminary  survey of surface



impoundments and their effects on ground water quality-1  The



major findings of the study are  summarized  below:



      0  There is a minimum estimated total of about 132,700



         sites in the United States where municipal, industrial,



         or agricultural impoundments are used for the treatment,



         storage, or disposal of wastes.  A large percentage of



         the sites contain more  than one impoundment,  and EPA



         expects that the total  number of impoundments is several



         times greater than the  total number  of  sites.



      0  Billions of gallons of  wastes are  placed daily in surface



         impoundments.   These wastes contain a  wide variety of



         organic and inorganic substances,  some  of which are



         highly hazardous.



      0  Most impoundments are unlined, and because a large



         percentage of them are  underlain by  permeable soils, the



         potential for downward  seepage of  contaminated fluids



         into ground water is high.  However, only incomplete



         data are available on the volumes  of surface impoundment



         fluids that are lost by seepage into the ground water,



         by evaporation, and by  discharge to  surface water bodies.



      0  Some contaminants that  seep from impoundments may be



         attenuated by the soil  by ion exchange, absorption, or

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         other geochemical reactions.  Others can move readily



         through soil and into shallow, unconfined aquifers,



         especially where the sorptive capacity of the soil is



         exhausted by continuous seepage of contaminated fluids.



      0  Incidents of ground-water contamination from impoundments



         have been reported in nearly all states.



      0  Case history studies generally show that the water in



         shallow, unconfined aquifers is the first to be contaminated



         by seepage of wastes from impoundments.  The contaminated



         ground water is generally in the form of a discrete



         plume that may be localized or that may extend as much



         as one mile or more downgradient from an impoundment.



      0  Costs of preventive or remedial actions at individual



         impoundment sites can range from tens of thousands of



         dollars to millions of dollars.



      An earlier EPA study^ of industrial waste disposal sites



monitored 50 sites; 20 of these sites used lagoons for treatment



and/or disposal of waste.  The study determined that:



      0  the ground water around 17 of the 20 surface impoundment



         sites had concentrations of contaminants above background



         levels



      0  9 of the 17 surface impoundments with contaminated ground



         water had one or more components exceeding EPA's Primary



         Drinking Water Standards



      0  11 of the 20 surface impoundments were onsite operations



      0  17 of the 20 surface impoundments were still active at



         the time of the study.  Their ages ranged from 4 to 40+ years

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         none of the 20 surface impoundments had any liner or



         leachate collection system



      As the above studies indicate, the movement of hazardous



wastes through a surface impoundment into the ground water has



contaminated ground water in numerous instances.  Ground-water



contamination can cause serious damage to human health and the



environment.  Ground water generally has little assimilation



capacity compared to the surface water which has such characteristics



as greater rate of flow, more mixing, and often larger volume.



Unlike streams, which can rebound from pollution conditions in a



few years, ground water does not experience the purifying effects



of air, light or aerobic biological activity.  Instead, it flows



very slowly, receives less dilution, has essentially no oxygen to



degrade pollutants under aerobic conditions.  Since the potential



for the ground water to recover from a polluted condition is very



low,  a high degree of ground-water protection should be provided



by the regulations.



      A preliminary report^ of the Surface Impoundment Assessment



conducted by EPA's Office of Drinking Water found that approximately



20% of the industrial impoundments are unlined and have the



potential for allowing contaminants to infiltrate unimpeded into



the subsurface.   The report also indicates that about 95% of the



sites have virtually no ground-water monitoring and approximately



50% of the sites may have potentially hazardous constituents.
                                 8

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      However, surface water pollution incidents relative to



hazardous waste surface problems have also been caused in ways



not controlled through permits issued under the Clean Water Act.



For example, surface water contamination can result from breaks



in the dikes or overtopping, with subsequent spilling over of



hazardous wastes into the surface waters.  Such incidents have




resulted in water contamination, fish kills, and degradation of



the stream.  Contamination can also occur through direct contact



of surface water      with a surface impoundment, particularly



during times of high water such as floods.  In addition, surface



water contamination can also result from contaminated ground



water feeding surface water.



B.    Reported Damage Incidents



      The treatment and disposal of hazardous wastes in a properly



located, designed, constructed, operated and maintained surface



impoundment can be an environmentally sound waste management



practice.  However, numerous incidents of damage have occurred



because of the improper location, design, construction, operation



or maintenance of such facilities.  A few examples of such



incidents are described below:



Surface Water



      0   A copper reclamation company operating in a mid-Atlantic



         state from 1965 to 1969 bought industrial wastes from



         other plants, extracted copper, and then stored the



         remaining liquids in 11 cement lagoons.  Three of these



         lagoons developed open seams on the bottom from which

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pollutants seeped into an adjacent creek, which became



lifeless.  Also, the plant grounds became reddish green



with sulfuric acid wastes.  The county and state, after



prolonged litigation, finally had an injunction issued



to have all wastes properly treated.  Rather than face



this expense, the company abandoned the site, leaving



the  lagoons filled with 3-1/2 million gallons of



hazardous wastes, and leaving rusting drums of hazardous



materials strewn about the property-  In April 1970,



heavy rains threatened to wash much of the wastes in the



lagoons into the Delaware River via the adjacent creek.



When overflow reached 25 gallons a minute, county



officials were  forced to have the disposal site sandbagged



and a dike built to prevent further overflow.  Had the



lagoons continued to overflow, the Trenton water supply



downstream would have been rendered unusable.  Because



of this danger, and a steady underground seepage from



three of the lagoons, the state was forced to assume the



expense of cleaning up the site.  At a cost of $400,000



the wastes were neutralized and dumped (in the ocean) in



1971.  Although the wastes no longer poses a threat to



surrounding areas, the original plant site is still



contaminated and devoid of vegetation.3





Cn September 27, 1972, heavy rains broke the earthen



dike of a former refinery waste lagoon which is currently



owned by Pleasant Township.  The released sludge entered



the Allegheny River and killed about 450,000 fish (with



                       10

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an estimated value of $75,000) along a 60-mile  stretch.




Analysis of the discharge entering the river at  that




time indicated the following: pH, 1.7; COD, 116,112 ppm;




iron, 507.3 ppm; sulfates, 56.5 ppm.  Tb stop the  leak,




the town built up the lagoon bank and has been




adding clean fill as available.  Monitoring wells  placed




near the lagoon show that the ground-water quality still



is degraded.^






On October 27,  1978,  a waste storage lagoon on the




plant site of a Pennsylvania refining company broke,




spilling waste sludge containing oils, acid wastes,




and alkyl benzene sulfonate into the south branch  of




Bear Creek, killing an estimated 4.5 million fish



valued at $180,000.  Because the company was in  poor




financial condition, only a little over $250,000 in




fines were levied to cover the damage.^






On June 10, 1967, a dike containing an alkaline




waste lagoon for a steam generating plant at Carbo, Virginia,




collapsed and released approximately 400 acre-feet




(493,400 cubic meters) of fly ash waste into the Clinch




River.  The resulting contaminant sludge moved at  a rate




of 1 mile per hour (1.6 kilometers per hour) for several




days until it reached Nbrris Lake in Tennessee, whereupon




it is estimated to have killed 216,200 fish.  All  food




organisms in the 4-mile ( 6.43-kilometer s) stretch  of




river immediately below Carbo were' completely eliminated. 10






                       11

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On December 7, 1971, at a chemical plant site in



Fort Meade, Florida, a portion of a dike forming a waste



pond ruptured, releasing an estimated 2 billion gallons



(7.58 billion liters) of slime composed of phosphatic



clays and insoluble halides into Whidden Creek.  Flow



patterns of the creek led to subsequent contamination of



the Peace River and the estuarine area of Charlotte



Harbor.  The water of Charlotte Harbor took on a thick



milky white appearance.  Along the river, signs of life



were diminished, dead fish were sighted and normal



surface fish activity was absent.  No living organisms



were found in Whidden Creek downstream of the spill or



in the Peace River at a point 8 miles downstream of



Whidden Creek.  Clam and crab gills were coated with the



milk^ substance, and in general all benthic aquatic life



was affected in some
A holding pond and tanks at a chemical manufacturing



plant in Saltville, Virginia, failed, spilling chlorine,



hypochlorities, and ammonia into the north  fork of the



Holston River.  River water samples showed  concentration



levels at 0.5 ppm hypochlorite and 17.0 ppm of fixed



ammonia.  Dead fish were sighted along the  path of the



flow in the river- ^






In December 1973, overflow from a waste impoundment



at a chemical company in Clinton County,  Pennsylvania,



caused pollution of Bald Eagle Creek, a tributary of

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the Susquehanna River.  In addition to the degradation
of the stream quality, the overflow also saturated soil
around the bed of the Pennsylvania railroad, causing
derailment of several railroad cars.  The prime contaminants
of the polluted waters were: chromium, copper, iron and
high BOD.15,25

A liquid industrial waste treatment and disposal
company in Portage County, Ohio has stored on its site
several thousand leaking barrels and a 300,000-gallon
cracked and leaking concrete storage tank.  The site
presents a fire hazard from the improperly stored barrels
and chemicals and oils carried in rain water runoff from
the site present the possible contamination of a drinking
water reservoir.  Some of the stored wastes include
acetone, MEK,  toluene, latex, oils, hexachlorocyclopentadiene
and mirex.  The cost to remove the wastes and secure the
site exceed $2 million.29

In Lowell, Massachusetts, a million gallons of
hazardous wastes, including solvents, waste oils, plating
wastes, toxic metals anc chlorinated hydrocarbons were leaking
from an abandoned toxic wastes disposal site.  Rain water
runoff caused contamination of Concord River's aquatic
environment.  Most of the wastes were removed at a cost to the
State of $1.5 million.  Another $600,000 is needed to finish
the cleanup.29

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Seventy-five hundred drums of chemical wastes of  unknown



composition are stored at an industrial site in Oswego,



New York.  In addition, wastes  have overflowed dikes at the



facility killing vegetation in  an adjacent wetland.  The



State appropriated $750,000 for remedial  work, however,



bids for the cleanup were far above the amount of money



available.29






Pickling liquors mixed with lime escaped  from improperly



lined lagoons in Butler,  Pennsylvania.  An estimated 400,000



gallons per day of liquid wastes with a pH of 2.6 contaminated



a nearby tributary of  Raccoon Creek.29





Mercury leaching from  lagoons on an industrial plant site



in  Saltville, Virginia contaminated the Holston River.  As



a result a fishing ban was imposed by the State.  The company



has spent  over $700 thousand to stabilize and protect  the



lagoon levees.  The remedial plan includes covering the lagoon



and diverting surface  water at  a cost of  $4  million.29






Seven pits in Whitehouse, Florida covering seven  acres were



filled with waste oil  sludge contaminated with PCBs and



abandoned  in  1968.   In  1976 the levee of  one of the pits



gave way and  about 50,000 gallons of  oily material was



released to McGirts  Creek.   In  additon to PCBs, some of the



sludge was found to be highly acidic  and  contained high



concentrations of lead, zinc, and copper. Remedial actions



are being  considered.29
                          H

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Heavy rains eroded a dike of a waste-storage pond



for hexachlorocylopentadiene owned by a chemical



company near Marshall, Illinois.  The wastes



contaminated two tributaries which fed into the Wabash



and Ohio Rivers above Franklin, Illinois.29






A pit near Lisbon, Ohio that was used for the disposal



of neutralized spent pickling liquids began to leak in



1970.  As a result fish were killed in nearby Wilson's



pond.  In 1971, Wilson's pond overflowed into Little



Beaver Creek causing a major fish kill.  As a result,



the company was required to install a collection system



and neutralization plant.  In 1978 the site was again



causing contamination due to ammonia discharges.  The



company will now be required to reclaim the area.29





A West Memphis, Arkansas oil company operated pits



for disposal of oily sludges for a waste oil recycling



operation.  The 3.5 acre site is now abandoned and



subject to flooding.  Oil has been released into surface



water.  Further releases have been controlled by pumping



after each rain.  Estimated cleanup is expected to be



between $700,000 and $1,000,000.  The sludges contain



PCBs, cadmium, chromium, lead and zinc.29






A company operated a waste disposal facility in Wichita,



Kansas.  In the early 1970's extensive air and water



pollution were caused by improper management practices.



Breached lagoons and contaminated runoff resulted in
                          \s

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numerous fishkills.  The company paid a $10,000 fine for a




1976 fishkill, and claims to have spent $8.9 million on




site cleanup and implementation of a comprehensive




waste management program is complete.  The Kansas Department




of Health and Environment and the EPA Regional Office




inspected the site and facility during the summer of



1979 and approved the clean-up effort.29






In 1979, a trucking  firm in Kent, Washington violated




water pollution laws when its settling ponds, used to




filter  liquid wastes out of its tanker trucks, overflowed




into an adjacent swamp.  Surface water was contaminated;




groundwater had apparently not been affected.29






Mercury contamination from mercury mine tailings




ponds near Red Devil, Alaska are entering a stream.




Studies in the areas have shown that over time elemental




mercury is converted to the highly toxic methyl mercury




by bacteria.  Methyl mercury then bioaccumulates in




aquatic life, rendering fish unfit for consumption.29






On March 11,  1977, a fire and explosion occured at a




remote  housing development in Jefferson County near




Dittmar, Missouri.  A portion of the property was used




to store barrels of waste, and liquid wastes were dumped




into a  pit.  After a nearby resident complained of strong




odors coming  from the property, the State investigated




the site.  Some of the containers had labels with the
                          1C*

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         notations "Toxic", Lab Samples", " Herbicides" , "Corrosive",



         etc.  An analysis of the pit contents showed  it contained



         34,000 ppm of polychlorinatedbiphenols.  A nearby creek



         contained dead aquatic life and an oily film  was found



         downstream of the dump site.  Total cost for  clean-up is



         estimated at $575,000.30
Ground Water
         Four private wells in an eastern state were contaminated



         with phenols in late 1972.  The phenols had leached



         from unlined disposal lagoons of a fiberglass



         manufacturing operation.  In January 1973, the phenol



         concentration in one of the wells was 1.64 parts per



         million (ppm).  As a remedial measure,  the leaking



         lagoons have been emptied and lined disposal lagoons



         have been installed.  Recently, one of the affected



         wells still had a phenol concentration of 0.138 ppm.4






         Nitrate and nitrite contamination in several wells



         at the Bangor Annex Naval installation in Kitsap



         County, Washington, was discovered in March 1971



         during routine sampling.  The Navy then began a



         program of monitoring 39 wells, 33 of which are off



         the Annex.  As a result, it was found that the shallow



         perched aquifer underlying the area contained RDX and



         TNT in concentrations of 5.2 ppm and  13 ppm,



         respectively.  The contaminants were also found to



         have penetrated the soil underlying this aquifer to a depth

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approximately 260 feet above the main aquifer.  The



contamination source was in an unlined settling basin



used to discharge wastewater from the washing of spent



bomb casings after removal of the insoluble solids.  As



a remedial measure, the upper six inches of residue were



removed and incinerated in 1971 and the basin backfilled



with four feet of soil.  An estimated 9,000 pounds of



RDX still remain in the soil of the basins.  The U.S.G.S.



has released a final report on its study of the problem



which recommends that the site be covered with an



immpermeable material and drainage controlled on the



upgradient side.  Currently, 11 wells are still monitored



in an operation which has cost the Navy $150,000 so far.



Final costs are estimated to approach 1 million dollars.^






A 1974 report stated that a lagoon on the Lexington-



Blue Grass Army Depot was found to be leaking and



contaminated underground water with cadmium.31






Unlined holding ponds containing complex mixtures of



chemical by-products from the manufacture of pesticides



and herbicides during the years 1943-1957 at the Rocky



Mountain Arsenal near Denver, Colorado have been infiltrating



the shallow aquifer.  To date, thirty square miles of



the shallow aquifer have been contaminated resulting in



the abandonment of sixty-four domestic, stock, and



irrigation wells.  Soil and water in the vicinity of a



pond and a slough have become contaminated by the pesticides




aldrin and dieldrin.29





                       if

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Liquid and solid wastes from the manufacture of



pesticides and fertilizer products at a plant in



Lathrop, California have for years been dumped into



unlined ponds, a lined pond, ditches and other



disposal areas.  The shallow groundwater which is



utilized by the Lathrop County Water District as well



as other domestic and public water supplies has become



contaminated with Dibromochloropropane (DBCP),



Lindane, and S,S,S-Tributyl phosphorotrithioate (DBF).



In addition, chemicals detected in the soil at the



facility or in the groundwater include: Chlordane,



Dieldrin, Heptachlor, Ethylene Dibromide, Dimethoate,



and DDT-  Concentrations of sulfates and nitrates



found in production wells in the vicinity of the



facility also exceed the Regional Water Board's



limits.29





A fertilizer plant in Big Flats, New York discharged



waste nitrate material into a lagoon.  Nitrates



contaminated the surrounding soil and ground water



resulting in nitrate levels above 100 ppm in



approximately twenty domestic wells.  Residents were



forced to drink bottled water until a public water



supply line became available.29






Unlined lagoons in Whiteland Township, Pennsylvania



were used for the disposal of lithium.  The resulting

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groundwater contamination caused the abandonment of
600 wells.29

Unlined lagoons of a manufacturing company in Berwick
Borough, Pennsylvania caused contamination of private
wells in the area.  The lagoons were leaking plating
wastes containing cyanide, copper, nickel, alkylbenzene-
sulphonate and phosphate.29

Explosive residues have been found in wells in the
vicinity of industrial lagoons on an army ammunition
plant in Tennessee.  The lagoons have received plant
process water  since 1941, which contains residues of
TNT, DNT, RDX and "tetryl".  As a result of the findings,
two water supply wells for the army installation were
closed and a survey of onsite and private wells downgradient
from the installation was instituted.29

Industrial waste holding ponds on a chemical company's
property adjacent to the Mississippi River in East Saint
Louis, Illinois received wastes from the mid 1960's
until 1974.  Wastes dumped into the holding ponds included
phenols, nitrobenzene derivatives, sulfuric acid and fly
ash.  In 1972 and 1974, tests of shallow wells at the
perimeter of the site showed phenol contamination.29

Solvents were dumped into unlined pits at a disposal
site in Woodbury Township, Minnesota until 1966.  Test
drilling on the site found isopropyl ether concentrations

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of 4-5 ppm in shallow drifts and 0.11 ppm at a depth



of 100 feet.  The pits have since been pumped out and



three wells are continuously pumped to stop the spread



of contaminants.  The contaminated water is discharged to



a treatment system.29






An aluminum plant in Monroe County, Ohio grossly



contaminated the groundwater under its site with flourides,



high pH and other trace chemicals; the water was also



discolored.  The source of contamination is leachate



from a used tailing pond and used potline pits.29






In 1979, high levels of chromate were found to have



contaminated drinking water wells in Riverside, Texas.



State officials believe that a leak in a cooling tower



basin at a private firm was the source of pollution.29






A Kansas City, Missouri chemical waste treatment/disposal



facility is located on the river-side of the flood



control level, at the confluence of the Missouri and



Blue Rivers.  The facility was operated since the early



1960's and consisted of three disposal lagoons, a



neutralization basin and several storage tanks.  The



site is located in sandy soil and groundwater contamination



has been documented.  In July 1977, the State of Missouri



ordered the company to close, stabilize and cover the



lagoons.  The closure plan has not yet been completed.



Additional groundwater monitoring is necessary to more




specifically define the extent of contamination.29






                        b?/

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A company which occupies 8,000 acres south of the American



River near Rancho Cordova/ California discharged waste



streams directly into an open pit.  Sulfates, pesticides



and heavy metals from Cordova Chemical have been found



in an old dredge pit where these chemicals were dumped



over a 2-year period.  TCE has also been found off-site.



There are 30-40 contaminated wells along Folsum Blvd.,



and one along the American River.  At present a "sewage"



lagoon contains drums of unidentified wastes as well as



several unlined surface percolation ponds and defective



lined ponds receiving wastes.  The State of California



has brought suit against these companies seeking remedial



actions.29






A research institute in Henderson, Nevada discovered



thirthion pesticides in a well 200 yards from the retaining



ponds of a chemical company.• Until 1973, the chemical



company had discharged the waste into unlined retaining



ponds.  It corrected its disposal in 1973, and waste is



now put into lined pools for evaporation.29






A chemical company in Tacoma, Washington has recently



reported to the State of Washington and EPA Region X



that the groundwater at the plant site is contaminated



by chlorinated organic chemicals.  The contamination



may be due to waste chemical migration from disposal
                        22.

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         areas and lagoons on the plant site.  Additional



         groundwater monitoring is necessary to define the



         extent of contamination.29






     0   In 1978, private residential drinking wells near a



         Spokane, Washington chemical plant were found to have



         significant concentrations of cyanide.  The apparent



         cause of the contamination is the company's practice



         of pumping liquid wastes containing cyanide into on-



         site lagoons or directly into the ground.   The cyanide



         apparently migrated easily through the sandy flatland



         which overlies the Spokane aquifer-^9





Surface Water and Ground Water



     0   Chromium from a waste lagoon of a New Jersey company



         contaminated a municipal well,  at least one domestic



         well, and a nearby stream in the 1960s.  The company



         had been in operation for about ten years  before the



         problem was recognized in 1970.  At that time, a total



         chromium concentration of 150 ppm was measured in one



         of the wells 700 feet away from the waste  lagoon.  The



         source of contamination has been eliminated, but the



         plume of polluted ground water is still there.  The



         former municipal drinking water well is currently used



         for industrial purposes only.6





     0   Arsenic compounds, the byproducts of pharmaceutical



         manufacturing operations,  were discharged  into sludge



         lagoons behind a Pennsylvania plant prior  to 1966.   By
                                ,23

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1966, the ground water in the vicinity of the plant



was contaminated with arsenic.  The ground water in



the area discharges into Tupehocken Creek which downstream



contributes to Philadephia's water supply.  Despite



persiste.it pumping of the ground water to reduce the



arsenic level, analysis of the creek water revealed an



arsenic concentration of 0.94 ppm in February 1975.



This is significantly higher than the"0.010 ppm arsenic



analyzed upstream from the plant site.  Arsenic from



the ground water is also seeping into the Myerstown



municipal sewer lines and entering the treatment plant.



Arsenic has been detected at a concentration of 0.285



ppm in the sewage effluent, which now will require



upgraded treatment to reduce this level.9






A company in the business of reprocessing industrial



solvents stored still bottom sludge from a distillation



process in lagoons from 1955 to 1967.  The water table



intersected the bottom of the unlined lagoons carrying



contamination downgradient, eventually to the



Quinnipiac River.  In 1967, the lagoons were cleaned



out and filled.  A public drinking water well was



installed in 1976 at some distance from the facility



but was later closed because contaminant concentrations



exceeded EPA drinking water standards.^4






Chemical wastes and septage were placed in trenches



and at least ten unlined lagoons at a sand and gravel

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pit near North Smithfield, Rhode Island.  Groundwater



contamination by 1,1,1 trichloroethane and toluene has



been documented.  In addition, analysis has shown that



trichloroethylene, benzene, toluent, ethyl benzene and xylene



were leaching into Tarklin Brook and Statesville Reservoir • ^9






Pickle liquors and organic wastes stored in a pit at



a treatment and disposal facility in New Beaver,



Pennsylvania resulted in the contamination of a nearby



pond and residential wells.  Although the site was



cleaned-up at a cost of $300,000, the groundwater has



not been restored.29






A trucking firm in Lake County, Ohio that hauls bulk



chemicals washes residues from tank trailers into two



lagoons on its property.  About 5,000 gallons of wash-



water, including phenols, organic solvents,  phosphates



and suspended solids were added to the lagoons daily.



Wells on adjacent property were contaminated and



cattle refused to drink from a stream polluted by



effluent from the lagoons.29






In Harris County, Texas there is a 15 acre waste



disposal site that has been in use since 1965.



Approximately, 70 million gallons of acidic and oily



wastes were disposed into this unlined, abandoned sand



pit.  The oily sludges and sediment of the pits



contain PCBs.  In 1973, flooding of the San Jacinto

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^missions
River inundated the site and caused the dike to break.



Some of the oily sludges were released.  The site was



again inundated in 1979.  Drinking water wells are



contaminated and a nearby sand pit closed due to the



movement of toxic pollutants.  The State has neutralized



the pH of the sludges as the first step of remedial action.



Substantial cleanup is required which may exceed $1,500,000










Annual production of organic lead waste from



manufacturing processes for alkyl lead in the San



Francisco Bay area amounts to 50 tons  (45.4 metric



tons).  This waste was previously disposed of in ponds



at one industrial waste disposal site.  Attempts to



process this waste for recovery resulted in alkyl lead



intoxication of some plant employees in one instance;



in another instance, not only were plant employees



affected, but employees of firms in the surrounding



area were also exposed to an airborne alkyl lead vapor



hazard.  Toll collectors on a bridge along the truck



route to the plant became ill from escaping vapors



from transport trucks.  Currently, the manufacturers



that generate organic lead waste are storing this



material in holding basins at the plants pending



development of an acceptable recovery process.13





In April 1977, 14 children at a Columbus, Indiana



elementary school got sick after inhaling fumes from a

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         nearby waste-disposal lagoon.  Prior to the incident



         xylene was dumped into the lagoon and began giving off



         a sulfurous odor.32




      0  A recycling company in Chester, Pennsylvania rec ^ved



         drums of hazardous waste which were dumped on the



         ground.  The site is in a residential area and presents



         a threat of fire and explosion with resultant toxic



         fumes.  The latest fire produced an acid mist.  Site



         clean-up which started in January 1980, may exceed $3 million.29






Fumes and Fire



     0   In Antioch, Pennsylvania, a 55-acre site contained



         several ponds containing sulfuric acid.  When water



         contacted the sulfuric acid in the ponds it reacted



         violently  (on several occasions)  generating fumes that



         required an evacuation of the entire city.  The industrial



         waste ponds have been dubbed "potential bombs" by fire



         officials in the city.  Their past efforts to cover the



         pond with wood pulp and garbage made the site quicksand-like



         and a potential fire hazard.15






     0   On July 25, 1978, in Bayou Sorrel, Tiberville Parish,



         Louisiana, a truck driver died while dumping a load of



         chemicals into a open onsite pit.  According to the



         coroner's report, the cause of death was hydrogen sulfide



         asphyxiation.  The gas was generated by mixing of imcompatible



         wastes.  Approximately 16 million gallons of hazardous wastes
                                    27

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         have been disposed at the site to date.  Surface drainage



         from the pits is potentially discharged into Grand



         River and other waterways.*5
Surface Water
         A farm near Coventry, Rhode Island was utilized as a



         repository for hazardous chemical wastes.  Flammable



         chemicals were dumped in ditch areas and approximately



         20,000 55-gallon drums of chemicals were stored on the



         farm.  A substantial explosion and fire occurred in



         late 1977.  Subsequent to the explosion, surface water



         contamination has been confirmed.  Site clean-up costs



         are estimated at $38 million.^9
Air and Surface Water
         Near LaMarque, Texas is an unsecured, abandoned dump



         site situated  in a  flood plain.  The generator to this



         site is a major chemical company.  There are 88 drums



         containing toluene, triethanolamine, acetic anhydride,



         lead and mercury.   Pits on the  site contain oily



         sludges.  Analysis  of these wastes reveal significant



         concentrations of PCB, benzene, phenol, stryene,



         trichloroethylene,  chloroform,  toluene, ethylbenzene,



         and xylene.  The site is causing air and surface water



         pollution problems.  Attempts at recycling the wastes



         were halted due to  vinyl chloride emissions.  Costs



         for containment are estimated to be at  least $100,000



         with cleanup expected to cost $1,500,000 to $4,000,000.29
                                28

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      The damage incidents described above plus other similar cases




contained in the EPA internal files15 clearly indicate that



improperly located, designed, constructed, operated or maintained




hazardous waste surface impoundments can pollute usable aquifers




and surface waters creating public health and environmental




hazard.




III.  SYNOPSIS OF PROPOSED REGULATIONS




      The propose? regulations for surface impoundments were




specified in §250.43-3 of the proposed hazardous waste regulations




published in the Federal Register on December 18, 1978 (F.R.,




Vol. 43, No. 243).  The surface impoundment regulations were




divided into the following subsections:




      1.  Site Selection




      2.  Hazardous Waste Suitable for Surface Impoundments



      3.  Design and Construction




      4.  Operation and Maintenance




      5.  Closure and Post Closure



      In addition, certain requirements applicable to all




facilities, such as waste analysis and recordkeeping and reporting,




were specified in General Facility Standards, §250.43, of the




proposed regulations.  Finally, these portions of the above




standards applicable to surface impoundments during interim status




were proposed in §250.40, Purpose, Scope, and Applicability.




      The content of the proposed full set of surface impoundment




regulations is summarized below.  It is followed by a summary of




the portions of those standards which were proposed as applicable



during interim status.  Then a synopsis is presented of those

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portions of the General Facility  Standards proposed as applicable



during interim status which are now addressed  in the surface



impoundment interim status standards.



A.    Summary of Proposed Full Status  Regulations



1.    Site Selection




      The  proposed regulations specified that:



      0  the surface  impoundment  not be  in direct  contact with



         navigable water



      0  the bottom of  the impoundment liner be at least five



         feet above the historical high  water  table



      0  the impoundment be at least 500 feet  from a functioning



         public or private water  supply  or livestock supply



      0  landslides,  slumping, and erosion be  minimized



      Variances to the  second and third of these  requirements



      were allowed based on demonstration by a permit applicant



      to the Regional Administrator  that water contact or contamination



      could otherwise be prevented.



 2.    Hazardous Waste Suitable for Impoundments



      The proposed regulation prohibited:



      0   ignitable,  volatile, and reactive waste  from being



          placed  in an  impoundment unless it could be demonstrated



          that airborne contaminants would not exceed certain



          levels  and  the structural  integrity  of the impoundment



          containment system  would not be damaged  through heat



          generation, fires,  or explosions



      0   mixing  of incompatible  wastes  in impoundments



      0   placement of  wastes which  would be detrimental to the
                                   3o

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          impoundment containment system as determined by testing



          of wastes for compatibility with liner materials used



          in the impoundment



3.    Design and Construction



      The regulation required no discharge to ground or surface



waters.  This was followed with a number of design and operating



requirements including:



      0  minimum thicknesses and permeability of soil liners used



         in the impoundment



      0  specified liner designs



      0  limitations on soil types acceptable for use in an



         impoundment



      0  minimum thicknesses, permeability and lifetime of



         artificial liners used in the impoundment



      0  a minimum soil cover (18 inches) over artificial liners



      0  ground-water and leachate monitoring systems



      0  minimum permeability of earthen dikes and a protective



         cover to prevent erosion.



      Variances to several of these requirements were allowed if



the permit applicant could demonstrate equivalent performance of



alternate designs to the Regional Administrator.



4.    Operation and Maintenance



      Requirements included:



      8  maintenance of a specified minimum freeboard



      0  keeping of records of contents and location of each



         impoundment



      0  maintenance of the integrity of the liners

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         daily inspection of dikes and monitoring systems to



         detect and correct any damage or deterioration



§•     Closure and Post Closure



      The proposed regulations required:



      0  removal of all hazardous wastes and residuals and disposal



         as a hazardous waste unless the impoundment meets the



         requirements applicable to a landfill



      0  for an impoundment which meets the requirements of a



         landfill, all hazardous waste must be either:



         - removed and disposed as a. hazardous waste, or



         - treated to a nonflowing consistency, followed by closure



           of the impoundment according to the landfill closure



           requirements



      0  filling of emptied impoundments with an inert fill material,



         followed by seeding with a ground cover crop or conversion to



         an alternative acceptable use



B.    Summary of Proposed Interim Status Standards



      The proposed interim status standards (§250.40(c)(21))



included the following portions of the above standards.



      0  Keeping records of the contents and location of each



         surface impoundment



      0  Daily inspection of dikes and monitoring system to detect



         and correct any damage or deterioration



      0  Removal of all hazardous waste and residuals and disposal



         as a hazardous waste unless the impoundment meets the




         requirements of a landfill



      0  For an impoundment which meets the requirements of a

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         landfill all hazardous waste must be either:




         -  removed and disposed as a hazardous waste, or




         -  treated to a nonflowing consistency, followed by




            closure of the impoundment according to the landfill




            closure requirements of §250.45-2(c) and  (d) of the




            proposed regulation




      0  Filling of emptied surface impoundments        with an




         inert fill material, followed by seeding with a suitable




         grass or ground cover crop, or conversion to an alternative




         acceptable use




      In addition, the proposed interim status standards included




certain recordkeeping and reporting requirements which were applicable




to all facilities.  These requirements were listed under the




heading of Manifest System, Recordkeeping, and Reporting Requirements




in the proposed regulations and interim status standards.




Manifest, recordkeeping, and reporting requirements applicable to




all facilities are described separately in §265.70 of the final




interim status standards.




      The proposed recordkeeping and reporting requirements




included                                        an operating log,




a record of the quantity and description of each waste received,




locations where each waste is treated or disposed and the methods




and dates of treatment or disposal, the results of the waste




analysis performed, monitoring data, reports of visual inspections,




and records of incidents requiring initiation of a contingency plan.




      Finally, there were certain requirements proposed in the




full regulations for surface impoundment, but not in the proposed
                                33

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interim status standards, which the  Agency feels  should be added




to the interim status requirements.




      The rationale  the  Agency has used  in selecting  those




standards to be applicable during  interim  status  is described  in




the preamble to the  Part 264  and 265 regulations  and  the background




document entitled  "  General  Issues Regarding  Interim  Status




Standards."  Since the  interim status standards apply prior to




the time a permit  application is acted upon,  the  applicable




standards have been  limited  to those specific design  and operating




conditions that are  fairly straight  forward and do  not involve




tremendous capital expenditures.




      However, the Agency believes that  it is important to make




the interim  status standards  as comprehensive as  possible.




Consequently, the  following  requirements from the full standards




have been added to those originally  proposed  to be  applicable




during  interim status:




       0  Maintenance of a minimum  freeboard in the  impoundment;




       0  Containment system  consisting of  protective  cover for




         earthen dikes;




       0  Restrictions on placing ignitable and reactive wastes




         in  surface  impoundments;




       0  Restrictions on incompatible wastes  in a surface




         impoundment; and




       0  Waste analysis.



IV.   COMMENT ANALYSIS  AND REGULATION RATIONALE




1.     ISSUE;  DEFINITION OF  SURFACE  IMPOUNDMENTS




A.    Proposed Definitions



      As proposed, "surface  impoundment" means a  natural topographic




depression,  artificial  excavation, or dike arrangement with the

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following characteristics:  (i) it is used primarily for holding,



treatment, or disposal of waste; (ii) it may be constructed above,



below, or partially in the ground or in navigable waters (e.g.,



wetlands); and (iii) it may or it may not have a permeable bottom



and/or sides.  Examples include holding ponds and aeration ponds.



B.    Comments on Proposed Definition



      1.  Water impoundments in the direct stream of flow through



          a process was'tewater treatment system should be



          specifically excluded in this definition.  The definition



          for "basins" is sufficient to include waste oil pits,



          skimming basins and other such installations related to



          wastewater treatment byproducts.



      2.  Expand definition to make it clear that this term refers



          exclusively to operations associated with hazardous



          wastes, as opposed to all wastes.



      3.  Clarify definition to specifically state that structures



          used for the sole purpose of spill confinement are not



          surface impoundments subject to requirements under



          Section 3004.



      4.  The distinction between "storage" and "impoundment" is



          not clear.  Impoundments are suitable and often used as



          feed reservoirs for underground injection, which the



          EPA refers to as "storage" prior to injection.   Unless



          definitions are greatly clarified, the requirement to



          "store" only in tanks or containers is unreasonable and



          should be deleted.

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5.   In the definitions of surface impoundments and basins



    at Section 250.41(b)(7) and 250.41(6)(85), respectively,



    an effort is made to distinguish between types of



    wastewater treatment units in order to allow different



    levels of regulation.  As currently written, the



    definitions of basins and surface impoundments are



    unclear, imprecise, arbitrary, and basically useless



    for their intended purpose.  Because of this, the proposed



    definitions create potential major problems in applying



    the regulations because the requirements under Section 3004



    are much more stringent for surface impoundments than



    basins and EPA's definitions are so vague.  If EPA



    intends for basins to be only aboveground tankage, they



    should so state; the current definition with the term



    "usually with a capacity of less than 100,000 gallons"



    has no meaning whatsoever in terms of wastewater



    treatment or, for that matter, solid waste disposal.



6.  This definition should be modified to specifically



    exempt dike arrangements around storage tanks.  These



    facilities are temporary storage facilities only and



    primarily collect rainwater; in the event of a spill,



    control and cleanup are covered by existing SPCC



    requirements under the Clean Water Act.  Any material



    that could be considered a hazardous waste which would



    enter the dike area would be removed expeditiously and



    then at that point would enter the hazardous waste



    disposal network.  The dike arrangement itself is not a
                           36,

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          storage or disposal facility and should not fall under



          Subtitle C regulations.



C.    Response to Comments



      The Agency agrees with the comment stating that the surface



impoundments are used also as storage facilities.  The confusion



resulted from the use of the term "holding" which can apply to



storage, treatment, or disposal.  Therefore, the term "holding"



has been replaced by "storage" in respect to the "use" of surface



impoundments.



      The Agency does not agree with comment No. 1, that the



impoundments in the direct stream of the flow through wastewater



treatment systems should be specifically excluded from the



definition.  All surface impoundments regardless of their use, if



they contain hazardous wastes, have a potential for ground water



and surface water contamination especially if they are not properly



constructed or operated.  Therefore, they should be regulated.



      The Agency does not concur with the recommendation in the



comment which stated that the definition should refer exclusively



to the operations associated with hazardous wastes as opposed to



all wastes.  The recommendation that the structures used for  the



sole purpose of a spill confinement should be specifically exempted



from the definition, is similar to the recommendation in the



comment concerning dike arrangements around storage facilities.



The Agency believes that it would be an "unreasonable" interpretation



of the proposed definition to interpret such structures as surface



impoundments.   The Agency does not believe that it can anticipate



and specifically exclude every such situation from the definitions.

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      The Agency has made changes in the definitions of both

basins and surface impoundments which  should eliminate the concerns

expressed that the definitions are vague and difficult to

distinguish.  However, since the comment provided little specific

information on how the definitions should be changed, it is not

possible to determine whether the comment has been  fully addressed.

D.    Revised Definition

      "Surface impoundment" or "impoundment" means  a facility or

a part of a facility which is a natural topographic depression,

man-made excavation, or diked area formed primarily of earthen

materials (although it may be lined with man-made materials),

which is designed to hold an accumulation of liquid wastes or

wastes containing free liquids and which    is  not  an injection

well.  Examples of surface impoundments are holding, storage,

settling, and aeration pits, ponds, and lagoons.

2.    ISSUE;  NEED FOR RECORDS OF THE  CONTENT AND LOCATION OF
      EACH SURFACE IMPOUNDMENT

A.    Proposed Interim Status Regulation and Rationale

      The proposed regulations required owners/operators to keep

records of the contents and location of each surface impoundment.

This requirement was an extension of other general  recordkeeping

requirements applicable to all facilities  (§250.43-5).

      There are several reasons for keeping such records.  One is

to avoid accidental mixing of incompatible wastes.  Over several

weeks, months, or years the contents of impoundments could easily

be confused by the owner/operator.  If, as a result, incompatible
                                38

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wastes were mixed, environmental damages could result.  Mixing of



incompatible wastes can result in fires, explosions, excessive



heat buildup, generation of toxic gases, or increased solubility



or mobility of hazardous waste constituents or byproducts.  Such



reactions could endanger workers or population in the vicinity of



the facility (e.g., from toxic fumes), or they could damage the



facility liner or dike and result in release of hazardous wastes



to ground water or surface water.



      The second purpose of records is to provide information



that could be useful in quickly resolving and correcting damage



incidents.  For example, such records could aid in identifying



the specific source of contamination in ground or surface water



contamination at or beyond the site.  They could help



identify the specific contaminants that could be leaking so that



the extent of potential public health damages could be assessed.



And they could help in determining the cause of the incident; for



example, types of wastes which may have caused a leak because of



incompatibility with the impoundment liner.



      Since surface impoundments may be used for waste treatment,



it is essential that good records of impoundment contents be



kept.  This will ensure that the wastes mixed in the treatment



process are properly identified and, therefore,  will help avoid



accidents from improper mixing such as those discussed previously



for incompatible wastes .



      Finally, such records could be useful at the time a facility



is closed.  If wastes are removed from an impoundment,  their



composition must be known to assure proper disposal and worker



safety.  If they are to be treated as a part of closure, knowledge

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of their composition is essential to proper and safe treatment.



      There is a precedent in state hazardous waste regulations



for keeping records of the contents and location of wastes in



impoundments.  The current regulations of Texas16 and Oklahoma1**



for "ponds and lagoons" require maintenance of records on the



quality and composition of the waste treated or disposed of in



the facility-



B.    Comments on the Proposed Regulation



      Comment was received supporting the regulation as proposed.



However, comment was also received that surface impoundments



utilized for one type of hazardous waste should be exempted from



the requirement that records be kept of the content and location



of each impoundment, if the owner/operator can demonstrate that



these records are not necessary.



C.    Response to Comments



      The Agency agrees that the  rationale presented above is



less compelling if an impoundment handles only one type of waste.



Compatibility and treatment would not seem to be issues, and



identification of damage  sources  would be greatly simplified.  On



the other hand, the  recordkeeping task in such situations would be



so greatly  simplified that it hardly seems significant, and such



documentation could  be  very important under certain future



conditions.  For example, a facility may deal with additional



types of wastes at a future date. Therefore, records of the type



of waste managed up  to  that time  at the  facility could be useful



to avoid compatibility  problems.  Furthermore, a facility could



change ownership.  The  type of  records discussed above would be



useful in preventing compatibility problems, aid in safe closure,

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or could be utilized for identifying causes or sources of damage



incidents.



      At impoundments receiving one type of waste, records can be



kept with a      minimum of effort.  There is no need for a detailed



day-by-day, impoundment-by-impoundment recordkeeping.  An



owner/operator can simply record the location of the impoundment



once and maintain a record that a given type of waste is being



placed in the impoundment   , until such time as the waste might



change.  Thus, the Agency believes that for facilities managing a



single waste type, the recordkeeping requirement is greatly



simplified, and would have a negligible time and cost impact on



the owner/operator.  The Agency does not believe exempting a



facility from such requirements represents sound environmental



management, and the final regulatory language was not changed



from that proposed.  Because all hazardous waste facilities must



keep records on the types and placements of wastes, the recordkeeping



requirements for surface impoundments are included in the general



recordkeeping requirements for all facilities under Subpart E.



Furthermore, comments on the proposed recordkeeping requirements



are discussed in the background document dealing with the manifest,



recordkeeping, and reporting requirements.



3.    ISSUE;  INSPECTION



A.    Proposed Interim Status Regulation and Rationale



      The proposed regulations required that surface impoundment dikes



be inspected daily for the purpose of detecting and correcting



any deterioration.  They also specified that any maintenance or



corrective action necessary to restore the dike to its original



condition can be accomplished expeditiously.





                                 •H

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      The reasoning behind the general requirement for all



facilities (including surface impoundments) to routinely inspect



their operations is discussed in the background document covering



the inspection regulations.  In brief, the purpose is to detect



and remedy noticeable deterioration or malfunctions of facilities



and equipment before they result in public health or environmental



damages.  Relative to surface impoundments, the primary objective



of the proposed regulation was to minimize the possibility of



impoundment dike failure by early detection of impending problems



and prompt corrective action upon detection of any dike deterioration.



      The primary function of any surface impoundment dike is to



contain the liquids and sludges within the impoundment area and



to serve as a barrier between the contained wastes and the



environment.  To serve its intended purpose, the dike should be



impermeable and structurally stable to prevent hazardous waste



seepage or release into the environment.  The structural integrity



and impermeability of dikes can be adversely affected by improper



operation, erosion, deterioration over time, or simply structural



breakdown due to stress.  As a result, a portion of the dike



could be washed away, develop cracks, or break, thus allowing



hazardous waste to be released into the environment.



      The breaching of dikes is known to be one of the primary



sources of surface water pollution problems relative to hazardous



waste surface impoundments.  A number of the damage cases presented



earlier in this document were the result of dike failure.  Dike



failure can also cause ground-water contamination.  If the soils



surrounding an impoundment are highly permeable, hazardous wastes

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released from the impoundment through slow leaks or rapid



discharges could quickly infiltrate into the area ground water.



Thus, detection, maintenance, or corrective action necessary to



restore the dike to its original condition should be accomplished



expeditiously to avoid potential ground-water and surface water



contamination.



      The proposed requirement for   daily inspection of dikes was



an extension of the general requirements for daily inspections



outlined in §250.43-6 of the proposed regulations.  The rationale



for that proposed requirement is discussed in the background



document on facility inspection.  In brief, the Agency felt that



daily facility inspections were necessary to ensure that



deterioration,  breakdowns, or malfunctions did not result in



releases of hazardous wastes into the environment.



B*    Comments on the Proposed Regulation



      The following points were made by commenters:



      0  Daily inspection is not necessary since dike failure is



         a long term event, often with early warning signs.



      0  Monthly inspection requirements would result in more



         thorough inspection, since daily inspection would probably



         be little more than a "drive-by" in practice.



      0  A weekly or twice weekly inspection would be more



         reasonable, particularly for facilities which are not



         operated on weekends.



      0  Daily inspection is not needed to assure physical



         integrity of the facility.  Should specify an inspection



         schedule based on probability and seriousness of a failure,



         for example, weekly for dikes.

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      0  The section should be deleted and replaced with a



         requirement that facilities be inspected as necessary to



         detect any condition that would result in a violation of



         the regulations.



C.    Response to the Comments




      As a result of comments received on the proposed general



inspection requirements  (§250.43-6), the Agency has restructured



the inspection requirements.



      The Agency believes that the commenters' suggestions for



less frequent inspections of dikes are well reasoned.  The primary



purpose of dike inspections is to detect deterioration that would



lead to dike failure, or to quickly detect leaks before significant



quantities of hazardous wastes are released.  Some types of



deterioration would normally occur slowly over several weeks or



months, so that a monthly inspection frequency would be adequate



to identify the problem.



      As with any inspection program, the more frequent the



inspection, the better the chances for detecting potential problems



before they materialize.  However, there is clearly a point of



diminishing returns regarding inspection frequency.  The Agency



believes that minimum weekly inspections will be sufficient to



detect cracks or other problems and correct them before they



become serious and that  the benefits of a daily inspection do not



justify the rigor of such an inspection schedule.  As a commenter



suggested, it would be particularly burdensome for facilities not



operated on weekends.  A commenter suggested that daily inspections



would probably be done in a cursory manner.  If this were the

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case, a daily inspection would be less effective than a weekly



inspection.   Consequently, the Agency believes that the weekly



inspections schedule suggested by several coramenters strikes an



appropriate balance between need and practicality.  It should



provide ample protection of the environment against dike failure.



      However, unusual rainfall events may cause significant



erosion of a dike.  Under such circumstances, cracks in a dike



might occur in a few hours and potentially develop into a leak.



To ensure against such a problem, additional inspection may be



required during or as a result of an unusual rain event and should



be provided for in the inspection schedule or plan.



      The proposed regulations only required inspection of dikes.



However, the Agency has decided to add an inspection requirement



with respect to the maintenance of freeboard.  EPA believes that



the real potential for surface impoundment failure on a very



sudden basis (i.e., within a day) is from overtopping.   This



potential is greatest when the surface impoundment is in operation



and receiving wastes.  It is at this point in time when the



freeboard requirement may not be met because of



significant fluctuations in the level of the wastes.  Therefore,



the final interim status standards require a daily inspection of



freeboard on those days when surface impoundment is in operation.



D.    Final Regulatory Language



      §265.226 Inspections



      The owner or operator must inspect: (1) the freeboard level



at least once each operating day to ensure compliance with



§265.222, and (2) the surface impoundment, including dikes and

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vegetation surrounding the dike, at least once a week to detect

any leaks, deterioration, or failures in the impoundment.

4.    ISSUE;  FREQUENCY OF VISUAL INSPECTION OF EQUIPMENT FOR
      DETECTING A FAILURE OF THE IMPOUNDMENT CONTAINMENT SYSTEM

A.    Proposed Interim Status Regulation and Rationale

      The proposed regulation required daily visual inspection of

any system provided for detecting the failure of a liner system

or natural in place soil barrier to ensure that it is operating

property  for the purposes intended.

      The objective of this specific inspection regulation was to

minimize  the possibility of failure of the leachate detection

system  (required in the proposed regulations) through routine

inspection. The daily inspection frequency was an extension of

the general requirements for daily facility inspections  (§250.43-

6).   See  the background document on facility inspection  for a

discussion of the daily inspection requirement.

      In  the proposed general  status regulation, leachate detection

systems and ground-water monitoring systems were required to

detect  any  failure  in a liner  and any migration of waste to

to ground water.  Periodic  inspection of ground-water monitoring

equipment was not required, since in performing the ground-water

monitoring  specified  in the regulations, the equipment would

automatically be  "inspected" as a part of  its periodic use.  Any

part  of the sampling  equipment (pump, pipes, etc.) that  did not

function  properly could be  quickly replaced.  However, the fact that

the  leachate detection  system  would come into use only in a detection

mode  during a problem occurrence suggested that it be periodically

inspected to ensure that  it was in good working order.
                               ft-

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B.    Comments on the Regulation




      Comments on this issue were similar to those made relative to




inspection of dikes.  Commenters made the following points:




      0  Daily inspection in "unreasonable" or "unnecessary" to




         provide adequate environmental protection.  (No rationale




         was included for this claim.)




      0  The frequency should be based on the probability and




         seriousness of a failure.




      8  Daily inspection might be necessary only for "certain high




         risk wastes."




      0  Facilities should be inspected as necessary to detect any




         condition that would result in a violation of the regulation.




      In making these points commenters suggested frequencies of




weekly, biweekly, or monthly as alternatives to daily.




C.    Response to the Comments




      The Agency has made a determination to drop the requirements for




leachate detection systems in the interim status regulations.  The




deletion of this requirement has been made because EPA believes




that many, if not most, existing surface impoundments are not




lined.  It would be technically impractical and costly to require




such facilities to be retrofitted with liners.  Because liners




are not required for surface impoundments under interim status,




there is little point in requiring leachate detection systems.




Inevitably, unlined existing surface impoundments are leaking and




there is little usefulness in requiring leachate detection systems



to detect existing leachate.  Consequently, the requirement for




inspection of these systems has also been dropped.  Since the

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inspection frequency is no longer an issue, no further response



to those comments is necessary.



5.    ISSUE;  MAINTENANCE OF MINIMUM FREEBOARD



A.    Proposed Regulation and Rationale



      The proposed regulation required that the freeboard maintained



in a surface impoundment be capable of containing rainfall from a



24-hour, 25-year storm, but be no less than 2 feet.  The requirement



was not included in the proposed interim  status standards.



However, after further consideration the  Agency has determined



that this standard meets the criteria established by the Agency




for interim status standards.



      It is accepted engineering practice to design surface



impoundments with sufficient freeboard to protect against



overtopping by waves or precipitation, and most surface impoundments



already have  2 feet of freeboard.  As discussed below, at  least



six states already require the  2-foot freeboard required in



these regulations.  As a result, an  interim status freeboard



will not typically require large capital  expenditures



by owners or  operators, nor  will it  require interaction with  the



Regional Administrator.  For those  facilities which do not meet



the minimum  freeboard  requirements,  the minimum freeboard  can be



established  in a  short period  of time by  such means as reducing



the quantity  of waste  or adding additional height to the dilces.



      The objective of the proposed  regulation was to prevent



spillover of  hazardous waste from the impoundment with the



subsequent   possibility of ground-water or surface water



contamination.   Spillover of wastes  in  an impoundment could be

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caused by at least three types of events.  For example, an



impoundment with inadequate freeboard could overflow if a pump



malfunctioned and failed to shut off or if an operator failed to



shut it off during normal operation.  Freeboard allows a margin



of safety for such occurrences.  If an impoundment has little or no



 freeboard, wave action from a storm or from hydraulic turbulence



as a result of pumping could cause wastes to be washed over the



sides.  Finally, a heavy rainstorm or continuous rain for an



extended period could raise the level in an impoundment and cause



it to overflow if freeboard were inadequate.



      If hazardous wastes are washed over a dike by means of any



of the events discussed above, they could run into surface waters



or migrate into ground water if soils are sufficiently permeable.



Overflows are a significant potential source of surface water



pollution relative to hazardous waste impoundments.  Part II of



this document contains damage cases which exhibit the kind of



damages that can result from overflows.  Many less significant



overflows may never be reported.



      One means of preventing the possible environmental damage



which could occur from impoundment overflows is to maintain a



sufficient freeboard to prevent or minimize the types of overflows



discussed above.  Another technique is to provide backup dikes or



other systems to collect and contain or treat any overflow from



the primary containment structure.  Finally, protection against



storms or overfilling could be provided by utilizing level controls,



pumps, and auxiliary impoundment capacity to automatically pump

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wastes out of an impoundment  (e.g., during  a  storm  or  extended



rains) and either put it in another impoundment or  treat  and



discharge it in accordance with NPDES  requirements. The  latter



technique can also be used to help maintain a minimum  of  freeboard.



      The States of  Texas, Oklahoma, Pennsylvania,  South  Carolina,



Oregon, and New York are among the states with              programs



for preventing ground-water and surface  water contamination from



management of hazardous wastes.   Each  of these states  requires a



minimum freeboard for surface impoundments.  Texas-^,



Pennsylvania17, South Carolina26, and  New York27  require  a  minimum



of two feet of freeboard for  all hazardous  waste  "ponds and



lagoons."  Oklahoma1^ and Oregon2** require  three  feet  of  freeboard.



California' s2^ regulations tie minimum freeboard  to the greatest



anticipated 24-hour  or  six-day rainfall  and wind  conditions,



whichever is more restrictive.



       Support for minimum freeboard of at least  2 feet can  be



found  in several technical documents.   For  example, a  minimum 2-



foot  to 3-foot freeboard is recommended  in  proceedings from a



symposium on upgrading  of wastewater treatment plants . 2<-*  A



minimum 2-foot freeboard is also recommended  in  proceedings from



a  engineers handbook on water pollution2^- and in  a  wastewater



engineering textbook*2^



       In developing  a freeboard requirement in the  proposed RCRA



regulations, the Agency considered all of the above information.



The Agency felt that a  2-foot minimum  freeboard  requirement was



adequate to address  all of the potential avenues  of spillover



with  the possible exception of rainfall  from  highly unusual and



 heavy storms.  A minimum freeboard was  deemed simpler, less

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costly, and more effective in preventing damages than a "backup"



dike system, and offered more complete protection than level



controls.   (Level controls would by design be set at some minimum



freeboard anyway.)



      Therefore, the Agency specified in the proposed regulation



that a minimum 2-foot freeboard must be maintained and also, that



freeboard must be sufficient to maintain the 24-hour, 25-year



storm.  The latter requirement was intended to address the



possibility that a 2-foot requirement would be insufficient to



address such a storm occurrence.  (A 24-hour, 25-year storm



occurrence was also used in other parts of the proposed regulation



as a "reasonable worst case" storm scenario.)



B.    Comments on the Proposed Regulation



      Commente»rs made the following points:



      0  The 24-hour, 100-year storm should be used instead of



         the 24-hour, 25-year storm (regulation should be more stringent.)



      0  The 24-hour, 10 year storm should be used instead of the



         24-hour, 25-year storm.  (Rationale was not clear, but



         seemed to suggest that the intent was consistency with



         regulations under Section 402 of the Clean Water Act).



      0  Requirements should be expanded to provide for total



         containment in the wettest year of record superimposed



         with a 24-hour.- 25-year storm while maintaining at least



         a  2-foot freeboard at the end of the occurrence (No



         rationale provided).



      0  The Agency should remove all requirements for any specific



         freeboard.
                                51

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      0   The proposed requirement does not take into consideration



         the fact that some companies are  allowed to discharge,




         through their NPDES permitted outfalls, the difference



         between rainfall and evaporation.  In those regions of



         the country where rainfall exceeds evaporation, any requirement



         for total rainfall containment would be an economic



         hardship on the industry of that region.  Further, the



         requirement would have the net effect of modifying the



         effluent limitations guidelines for certain categories,



         like bauxite refining, without going through procedural



         steps mandated under the Clean Water Act.



C.    Response to Comments



      The Agency has reconsidered the impacts of the 24-hour, 25-



year storm and found that it is a less stringent requirement than



the proposed 2-foot minimum freeboard.



      The 24-hour, 25-year storm produces a maximum equivalent of



less than 12 inches of rain in 24 hours.25  Consequently, the



Agency felt that this was a redundant and unnecessary part of the



regulation.



      Similarly, the 2-foot minimum requirement also overrides a



24-hour, 10-year storm and the 24-hour, 100-year storm suggested



in the comments.25  Therefore, the Agency sees no need to maintain



the storm requirement unless there is a need for the requirements



to be additive, that is, maintenance of 2 feet of freeboard during



a 24-hour, 25-year storm.  Since a key purpose of the freeboard



is to contain such a storm, this additional protection does not



appear warranted.  Having less than 2 feet of freeboard during a
                               5*2.

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storm does not present a problem as long as the precipitation is



contained, and the facility is expeditiously returned to having a




minimum 2 foot freeboard.



      A similar rationale applies to a commenter's suggestion



that   total containment be provided/ sufficient to include



(additively) precipitation from the wettest year on record, a 24-



hour, 25-year storm, and a minimum 2 feet of freeboard.  No



specific rationale for the requirement was provided in the comment.



However, this comment raises an issue of how freeboard can be



maintained if precipitation exceeds evaporation and the impoundment



is not otherwise leaking or discharging.  If an owner/operator



has no mechanism for controlling the level in the impoundment,



presumably it would rise continuously under such conditions, even



if no wastes were being added to it.



      To control this situation, the Agency believes that many



impoundments will have to be equipped with some mechanical means



of level control in order to maintain freeboard and prevent



overflow of wastes.  For example, impoundments will either have



to have an effective mechanism for level control, such as NPDES



permitted discharge system, or a mechanism for pumping wastes to



another (surge) pond or basin, or a means of collecting any overflow



(e.g., through secondary dikes) and containing or treating it.



However, the Agency prefers to give owners/operators the flexibility



of maintaining the 2 feet of freeboard in any legal way they



choose.  Consequently, the Agency has rejected specifying either



level controls or a freeboard sufficient to maintain both storms



and continuous rains over a period of time.
                              5-3

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      Another commenter suggested that there should be no minimum



freeboard requirements for NPDES permitted facilities allowed to



discharge the difference between precipitation and evaporation.



If rainfall were the only issue addressed by the freeboard



requirements this would perhaps be a valid approach for those



particular facilities with such capability.  However, freeboard



also provides a margin of safety against overflows from pump



malfunctions or operator errors and against wave propagation from



pumping or windstorms.  In order to provide protection from



overflows due to these occurrences and to provide an additional



margin of safety  during sudden storms the Agency believes that a



minimum freeboard is essential.



      In view of the above considerations, the Agency has maintained



the requirement of a minimum  2-foot freeboard for surface



impoundments, but has dropped the reference to the 24-hour,



25-year storm.



      The Agency believes that in order to prevent overtopping



and maintain the appropriate  freeboard, a surface impoundment may



require the use of a conduit, pipe, or other conveyance for the



discharge of excess wastes.   In fact, many treatment systems



consist of two or more impoundments in series, allowing for



aeration or other treatment and settling of solids while the



cleaner fluid flows to the next impoundment.  If these wastes are



discharged to waters of the United States, they are subject to



the NPDES requirements of the Clean Water Act.  EPA is concerned



about the owner's/operator's  awareness of the interface of such a



discharge with the Clean Water Act requirements.  Therefore, EPA

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has provided an informational comment to the general operating



requirements stating that any such discharge to waters



of the United States is a point source subject to the requirements



of Section 402 of the Clean Water Act.  Also, the comment further



states that a spill from an impoundment may be subject to Section



311 of the Clean Water Act.



D.    Final Regulatory Language



      §265.222 General Operating Requirements



           A surface impoundment must maintain enough freeboard



           to prevent any overtopping of the dike by overfilling,



            wave action, or a storm.  There must be at least 60



            centimeters (2 feet) of freeboard.



            [Comment:  Any point source discharge from a surface



            impoundment to waters of the United States is subject



            to the requirements of Section 402 of the Clean Water



            Act, as amended.  Spills may be subject to Section



            311 of the Act.]



6.    ISSUE;  PROTECTIVE COVER FOR DIKES (Containment System)



A.    Proposed Regulation and Rationale



      The proposed regulation required that all earthen dikes



have a protective outside cover (e.g., grass, shale, or rock) to



minimize wind and water erosion.



      The requirement was not included in the proposed interim



status standards.  However, upon reexamination the Agency has



determined that this standard meets the criteria established by



the Agency for interim status standards.  Protective cover for



earthen dikes is considered to be standard engineering practice,






                                55

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and many impoundments already have such a cover.  Therefore, the



Agency does not believe that a substantial capital cost, or any



interaction with the Regional Administrator, will be necessitated



by this requirement.




      The objective of this regulation is to help maintain the



structural integrity of a dike.  The potential consequences of



failure to provide adequate protection against erosion by wind



and water is the deterioration of structural stability, possibly causing



breaching of the dike and subsequent release of hazardous wastes



to the environment.



      All soils used in dikes will require some type of protection



in zones subject to turbulence and agitation.  Such zones can be



created by wind-induced wave action, inlet and outlet increased



hydraulic activity, and aerator agitation.  Turbulent zones occur



around the discharge areas where wastes enter the impoundment, at



recirculation pumping stations, and areas around the influent and



effluent connections.



      Erosion protection on the interior dike walls can be provided



by cobblestones, broken or cast-in-place concrete, wooden bulkheads,



asphalt strips, etc.  The erosion protection selected should provide



both control of shorelines and control of aquatic growth.  Exterior



slopes of the dike are also subject to erosion by wind and rain and



require stabilization by a protective cover (e.g., grass, rocks, etc.).



B.    Comments on Proposed Regulation



      The only comment received on this regulation expressed



support for it as proposed, but did request that EPA point out

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that the purpose of protective cover is maintenance of the




structural stability of the dike.



C.    Response to the Comments




      The Agency believes that the comment provides a very good




and important point.  The intention of the proposed regulation



was the protection of the structural integrity of an earthen




dike.  However, adding language to manifestly  effect the




commenter's suggestion will make this intention more explicit.




Consequently, the final regulatory language specifies the




requirement for preserving the structural integrity of an earthen




dike.




D.    Final Regulatory Language




      §265.223 Containment System




      All earthen dikes must have a protective cover, such as




grass, shale, or rock, to minimize wind and water erosion and to




preserve their structural integrity.






7.    ISSUE;  RESTRICTION ON INCOMPATIBLE WASTES




A.    Proposed Regulation and Rationale




      The proposed regulation prohibited placing incompatible




wastes (as defined in Appendix I of the proposed regulation) in




an impoundment.




      The requirement was not included in the proposed interim




status standards.  However, upon reexamination the Agency has




determined that this standard meets the criteria established by




the Agency for interim status standards.

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      The objective of the proposed regulation was to prevent



reactions between incompatible wastes that could harm facility



personnel, emit hazardous air contaminants to surrounding



populations, or damage the structural integrity of the impoundment.



Mixing of hazardous wastes that are not compatible with each



other in hazardous waste surface impoundments can result in



environmental problems such as fires and explosions, excessive



heat generation, or production of toxic gases.



      For example, mixing alkaline wastes which contain cyanide



and sulfide with acidic wastes will release toxic HCN and H^S



vapors into the environment.  Uncontrolled mixing of concentrated



acidic and alkaline wastes could result in violent reactions and



excessive heat generation and subsequent environmental problems.



Mixing of hazardous wastes containing highly reactive components



(e.g., oxidation-reduction agents and organics, etc.) could result



in explosions and fires.



      In order to prevent such occurrences, the Agency proposed a



prohibition on placing such wastes together in an impoundment.



The types of wastes which, if mixed, could cause such reactions,



were defined in Appendix I of the proposed regulation.



B.    Comments on the Proposed Regulation



      The restriction on incompatible wastes in the proposed



regulations went beyond surface impoundments.  Similar restrictions



were included in the proposed regulations for all treatment and



disposal  facilities under §250.45, standards for landfills under



§250.45-2, and standards for basins under §250.45-5.  The background



documents dealing with those standards contain additional analyses



of comments on this issue.

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      Those comments which were directed specifically toward



prohibitions on incompatible wastes in surface impoundments are



as follows :



      0  Support for the regulation as proposed.



      0  Some surface impoundments are designed for treatment of



         wastes, such as addition of lime to acid wastes for



         neutralization, addition of a reactant for chemical



         destruction, etc.  Where the impoundments are properly



         designed for treatment,  such treatment should not be



         prohibited.



      8  This section as written will prevent controlled



         neutralization of certain wastes.



      0  Prohibiting the mixing of incompatible waste will prevent



         the controlled mixing of incompatible wastes for



beneficial mixing of incompatible wastes for the purpose of



treatment.  Neutralization was mentioned in several comments as



such a practice.  It was pointed out that such treatment can be



carried out without posing hazards.



      The Agency agrees with the comments and has modified the



regulations to allow the mixing of potentially incompatible wastes



or incompatible wastes and materials.  This treatment must be



carried out in such a way that it will not generate excessive



heat, or pressure, flammable fumes or gases in sufficient quantities



to pose a risk of fire or explosion, fires or explosive reactions,



violent reactions, toxic mists or dusts, or any reaction that



would damage the structural integrity of the

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impoundment or damage human health or the environment.  Appendix V

of the final interim status regulation gives examples of pairs of

incompatible wastes which either must not be mixed or which can

be mixed with proper safeguards.  It also now includes an expanded

discussion of incompatible wastes, including concerns for increased

solubility and mobility, and the mixing of acids with water and

acids with bases.

D.    Final Regulatory Language

      Incompatible wastes, or incompatible wastes and materials,

(see Appendix V  for examples) must not be placed in the same

surface impoundment, unless §265.17bis complied with.

8.    ISSUE;  RESTRICTION ON PLACING IGNITABLE AND REACTIVE WASTES
      IN A SURFACE IMPOUNDMENT

A.    Proposed Regulation and Rationale

      The proposed regulations, 250.45-3(b), prohibited placing

ignitable, reactive, or volatile waste in a surface impoundment

unless certain conditions in a variance were met as specified in

§250.45.  The variance required that it be demonstrated that

airborne contaminants would not exceed a specified concentration,

and that there would be no damage to the structural integrity of

the facility.

      This regulation was not included in the proposed interim

status standards.  However, after reexamination, the Agency has

determined that  it meets the criteria established by the Agency

for interim status standards.

      The objective of the proposed regulation was to prevent

damages to the public health and the environment which could

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result from fires or explosions in a surface impoundment.  Placing



ignitable or reactive wastes in an impoundment presents three



potential problems.  One problem is the contamination of the air



through volatilization, since most ignitable and some reactive



wastes have relatively high vapor pressures.



      A second problem is that ignitable and reactive wastes can



explode or burn easily, injuring the personnel at the facility



and releasing toxic fumes into the air that can reach surrounding



populations and cause personal and property damage.



      The third problem is that fires, or explosions caused by



ignitable and reactive wastes, can damage the structural integrity



of the impoundment and cause rupturing of a dike or liner with



subsequent leaks of hazardous wastes into the ground-water or



surface water.  For example, many synthetic liners could be melted



by a fire, and almost any liner could be ruptured by an explosion.



      In the proposed regulations, the Agency stopped short of a



complete ban on placing ignitable and reactive wastes in surface



impoundments by providing a variance in a note to the regulation.



The variance would have allowed placing these wastes in impoundments



as long as the permit applicant could provide assurance that the types



of potential damages mentioned above would not occur, i.e.,



excessive volatilization and damages from fires or explosions.



The purpose of the variance was to provide flexibility to facility



owners/operators as long as the practice could be carried out



with minimal potential for damages to public health and the environment.
                                   (.1

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B.    Comments on the Proposed Regulation



      The restriction on ignitable, reactive, and volatile wastes



in the proposed regulations went beyond surface impoundments.  A



general restriction on placement of such wastes in landfills,



surface impoundments, basins, and  landfarms was included in



§250.45-2 of the proposed regulations.  Standards for landfills



under §250.45-4, and landfarms under  §250.45-5 also contained



such a restriction.  The reader is referred to the background



documents on these regulations for further analysis of comments



on this issue.



      Those comments received which were directed specifically



toward restrictions on ignitable and  reactive wastes in surface



impoundments are as follows:



      0  Support for the regulation as proposed.



      0  Prohibiting storage of ignitable and volative wastes in



         impoundments is unreasonable.  It will seriously impact all



         refineries and disallow use  of storm water surge ponds.



      0  Petroleum refineries maintain emergency wastewater



         retention ponds and storm water retention ponds which



         may on occasion contain volatile oils and/or sulfides.



         Oil spill contaminant ponds  are encouraged by EPA under



         Spill Prevention Control  Coordination  (SPCC) plans, and



         these emergency and storm ponds are necessary in water



         quality control.   EPA should make allowance for such



         special situations.



      0  Ignitable waste  (e.g., inorganic oxidizers) that could



         be a hazard in a facility where wastes are indiscriminantly

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         mixed present no hazard in an impoundment (in aqueous



         solution) if minimal good management practices are



         followed.  The only alternative, incineration, would



         likely cause greater environmental damage than placement



         in a surface impoundment, where seepage to ground water



         presents no known or reasonably conceived harmful consequence.



      0  Onsite impoundments are readily controlled to accept



         "reactive" waste containing sulfides.  The degree of



         danger of acidification is the same as it would be in a



         closed container.  Prohibiting such use of impoundments



         and requiring liners for full containment is unreasonable



         and unwarranted.



      0  There should not be a complete prohibition on any quantity



         of ignitable, reactive, or volatile waste.  Such wastes



         have been handled without major incident.  Some quantitative



         limitation should be placed on the exclusion, to allow



         continued handling of small volumes of these materials



         without having to "prove the negative" specified in the



         note to the standard.



C.    Response to Comments



      Germane to the discussion of the comments above is the fact



that the Agency, in response to comments on the variance in §250.45(c)



dealing with volatility,  has found it necessary to defer any



requirements relative to controls on volatiles.  Similarly, the



variance in 250.45(c) regarding concentration of airborne



contaminants has been deferred and will be reconsidered when the Agency



addresses restrictions on volatile wastes.
                                    (.3

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      Several commenters suggested that the "prohibition" was



unreasonable/ and they seemed to have overlooked the note to the



standard which allowed for a variance to the prohibition if



certain conditions were met.  One of these conditions was that



the concentration of airborne contaminants not exceed a specified



level, a requirement that has now been deferred.  The other condition



was that the owner/operator demonstrate that the structural



integrity of the contaminant system would not be damaged.



      Although specific comments were not received on this latter



condition of the variance, the Agency did receive a number of



comments broadly addressing the subject of "note" in the regulations.



These comments frequently criticized the notes as being too vague



and not providing sufficient guidance on what would constitute



adequate compliance.



      The final interim status regulation is based on the premise



that  ignitable or reactive wastes can be handled safely in an



impoundment  if "good management practices" are followed, and that



the clearest example of good management practice would be to



render the wastes nonignitable or nonreactive before, or immediately



after, placement in the impoundment.  To allow a broader variance



for "good management practice" would not be sufficient to assure



protection against damages unless other types of acceptable good



management practices could be specified.  The only practice which



the Agency feels it can define as acceptable at this time is the



practice mentioned above.



      The comment regarding quantity limitations to allow handling



of small quantities of ignitable or reactive wastes is already

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addressed in the regulations.  Subpart A of the final regulations,




§265.l(b), defines a small quantity cutoff, a generation rate




below which wastes are excluded from the requirements of these




interim status regulations.  The background document on small




quantities discusses the rationale for the cutoff selected for




ignitable and reactive wastes.  The Agency believes that waste




quantities above this limit must be managed in accordance with




the requirements of the regulations.   Since the comment on this




issue presented no recommendations for what such quantity




limitations should be for surface impoundments, it is not possible




to determine whether the quantities the commenter had in mind are




within the limit defined in Subpart A.




      Commenters also argued that the proposed regulation would




place an unreasonable restriction on storm water surge ponds and




other emergency wastewater retention ponds at oil refineries.




The comments also pointed out that such ponds are encouraged by




EPA under SPCC plans and that they are necessary in water quality




control.



      The Agency agrees that such storm surge ponds and emergency




retention ponds are necessary.  Further, it would not be possible




to address the conditions associated with these ponds, since the waste




enters the impoundments under emergency circumstances.  Consequently,



the Agency has included this special situation as a variance to




the restriction on ignitable wastes.




      Finally, comment was received that some "onsite" impoundments




are readily controlled to accept certain reactive wastes (such as




those containing sulfides).  The Agency concludes that such types

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of reactive wastes can be properly managed in an impoundment if




they are kept separated from those substances with which they




react.  This type of control in effect renders the waste to be




nonignitable or nonreactive.  Consequently, the final regulation




includes an allowance for this condition by requiring the waste




be treated or rendered non-ignitable or nonreactive prior to or




immediately after entering a surface impoundment.




D.    Final Regulatory Language




      §265.229 Special Requirement for Ignitable or Reactive Waste




       Ignitable and reactive wastes must not be placed in a




surface impoundment unless:




      (1)  The waste is treated,  rendered, mixed prior to or




           immediately after entering the impoundment so that




           (i) the resulting waste, mixture, or dissolution of




           material no longer meets the definition of ignitable




           or reactive waste under §§261.21 or 261.23 of this




           chapter; and  (ii) §265.17(b) is complied with; or



      (2)  the surface impoundment is used solely for emergencies.




9.    ISSUE;  CLOSURE AND POST-CLOSURE REQUIREMENTS




A.    Proposed Interim Status Regulations and Rationale




      The proposed regulations contained  four separate requirements




regarding closure and post  closure.  They required that, upon




    closure:




      0  all hazardous waste and  residuals must be removed from




         the impoundment and disposed of  as a hazardous waste,




         unless the impoundment meets the landfill requirements




         under §250.45-2 of the proposed  regulation.

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      0  for those impoundments which do meet the criteria for



         landfills, the hazardous wastes and residuals could be



         either removed and disposed as a hazardous waste, or



         treated to a nonflowing consistency followed by closure



         of the impoundment as a landfill,



      0  emptied surface impoundments must be filled with an



         inert fill material and seeded with a grass or other



         cover crop or converted to another acceptable use.



      0  surface impoundments closed as a landfill must meet all



         post closure requirements for landfills under §250.45-2(d).



      The objective of the above regulation was to prevent



environmental damage from improper closure by only allowing



retention of hazardous wastes and hazardous residuals in impoundments



which were designed and constructed to contain hazardous components



on a long term and permanent basis.



      The proper closure of surface impoundments is essential for



protection of public health and the environment.  The hazardous



waste or hazardous waste residuals (e.g. liners saturated with



hazardous wastes) remaining in the impoundment after its active



life can become a major source of environmental problems if the



facility fails to contain these wastes.



      The damage cases described earlier in this document show



that hazardous wastes in a surface impoundment can be a major



source of environmental damage due to failure of the containment



system and subsequent leaks into the ground water or surface



water.  The cost of restoring aquifers after they become contaminated



is prohibitive, and the potential for the ground water to recover

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from polluted conditions is generally very low.  Consequently, proper



closure of a facility after its useful life is essential in order



to protect public health and the environment.



      Leaving waste unattended in an impoundment after closure



could result in a high probability of ground water contamination.



For example, the potential for infiltration of the liner by the



wastes would exist as long as liquid remained in the impoundment.



The hydraulic head created by the waste would promote infiltration.



Rain falling on the facility would continually add liquid which would



both add to the hydraulic head and/or migrate through the liner



materials, possibly carrying with it hazardous constituents.  It



is also possible that any synthetic liners used in an impoundment



could ultimately deteriorate after prolonged contact with the waste.



      In view of these points, the proposed regulation required



that all hazardous wastes and residuals be removed from an



impoundment.  An exception was provided for those impoundments



with a containment system designed in accordance with landfill



requirements.



      However, even with such a containment design, the standing



liquid in the impoundment would have to be eliminated in order to



support and to prevent infiltration of precipitation.  Thus,  the



regulation required that all liquids be treated to a nonflowable



consistency and that the facility be closed in accordance with



landfill closure procedures, which include a properly maintained



cover.



      The primary reason that an emptied  impoundment was required



to be filled with an inert material was to prevent conversion to

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an open dump since the emptied impoundment might be filled with



anything, including trash or other waste.  Filling an impoundment




with an inert material would also add to the potential for future




productive use of the land and prevent the accumulation of rainfall



or snow melt in the empty impoundment.




      Finally, the proposed regulation required that all post-




closure provisions for landfills be applicable to closed surface



impoundments, since the need for post-closure care would be




identical in either case.  The rationale for post-closure




requirements for landfills is presented in the background document



dealing with that subject.




      The comments on the proposed closure requirements and




responses to those comments are presented below,  organized by




major issues.  The final regulatory language for the complete




closure requirement is presented after all comments are discussed.




B.    Comments on the Proposed Regulation




1.    Closure as a Landfill




      0  Section 250.45-3(e)(2) is inconsistent.   It provides for




         the removal and disposal of hazardous waste upon final




         closeout of impoundments which meet the landfill criteria



         under 250.045-2.  Assuming that the impoundment meets




         the criteria for a landfill, there is no reason to remove



         the hazardous waste.




      0  The proposed rules should clarify what requirements must




         be met for the permanent disposal of hazardous waste in a



         surface impoundment.

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      0   By  its  nature,  a surface impoundment cannot comply with



         all regulations of a landfill,  therefore,  the requirements



         which must be met, especially at closure,  should be set



         forth more explicitly in the regulation.



      0   The requirement that waste be removed if a surface



         impoundment meets the criteria for a landfill is not



         reasonable because if the landfill requirements are met,



         closure as a landfill should be allowed.



      0   Section 250.45-3(e)(2)(ii) should be clarified so that an



         impoundment can be converted to a landfill either at



         closure or gradually during the life of a facility by



         sectioning off portions of a facility.



      0   The requirements for surface impoundments and landfills



         should  be made more compatible in recognition of fact



         that most surface impoundments are designated for



         permanent waste disposal.  Such categorization would be



         more in line with the intent of the Act,  which is to



         conserve resources and protect the environment.



      0   The regulation should allow permanent disposal in any



         basin,  impoundment, or other facility which meets the



         landfill provisions for protection of ground water, or



         for existing facilities which can be shown by monitoring



         to protect ground water.



2.     Feasibility and Desirability of Waste Removal



      0   Support the regulation proposed.



      0   In cases of metal mining, given the relatively large



         size of impoundment, heavy machinery would have to enter

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         an impoundment to remove the waste.   This would create



         substantial risk to human health and environment in



         several ways,  i.e.,  increase the risk of damage of



         structural integrity of impoundment,  increase the possibility



         of damage to the liner,  and increase direct human exposure



         to hazardous waste.   After removal,  hazardous waste



         would have to be transported elsewhere for final



         disposition, thus increasing hazard  to human health and the



         environment because of greater amounts of handling and



         movement of hazardous waste.



      0   Naturally occurring substances,  such as crude oil placed



         in surface impoundments,  should not  be included under



         landfill requirements of Section 250.45-2.   Crude oil,



         where covered and worked into soil during closure of



         facility, should fall under the land treatment Section



         250.45-5 of the proposed regulation.   Crude oil will



         biodegrade by natural action and will not harm human



         health and the environment.



      0   If EPA retains the provision for removal of wastes, this



         requirement should be emphasized in  the preamble.



         Surface impoundments, basins, and chemical, physical,



         and biological treatment facilities  as described in the



         draft regulations should be strongly described as being



         "intermediate" facilities.



3.     Filling of an Impoundment Where Waste Has Been Removed



      0   Why is inert fill material specified?  There may be



         situations in which it would be desirable to partially
                                "71

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         fill large impoundments with material which is not inert,



         reserving soil materials only for final cover.  Change



         regulations to read:  "... shall be filled, graded, and



         seeded..."




      c  The implication of this paragraph is that a new "inert"



         material must be brought in to replace the excavated waste.



         An alternative closure method for impoundments with



         above-grade dikes is to push the dike into the excavated



         space and level the area.  The dikes are, in effect,  the



         "inert" material.  The regulation should allow other



         construction techniques, such as filling and leveling



         with old dike material, in addition to filling with



         "inert" material.



      0  For generator owned onsite and offsite facilities,



         delete this requirement.  If hazardous materials have



         been removed, there is no necessity for fillings.



C.    Response to Comments



1.    Closure as a Landfill



      Apparently several commenters misinterpreted the closure



options presented in the regulation.  The regulation did offer as



an option that a surface impoundment which met the criteria for a



landfill could be closed as a landfill without removal of the waste.



      Commenters requested clarification on the specific criteria



that a surface impoundment would have to meet in order to comply



with the closure stipulations in the proposed regulation.  One



commenter correctly pointed out that it was not possible for a



surface impoundment to comply with all landfill criteria.

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      It is evident that the proposed regulation was read by many




commenters to allow existing surface impoundments to close as




landfills under interim status only if they met the proposed




general standards for design and construction of landfills as




well as the standards for closure.  Understandably, this drew




strong objections.  Such a requirement was not applied to landfills




closing under interim status, and it was not intended to be




extended to surface impoundments.  Although it was not well




reflected in the text of the proposed regulation, the Agency's



intent was to require surface impoundments closing under interim




status as landfills to meet only the interim status requirements for




closure of landfills, that is, the closure and post-closure care




requirements for landfills.  The present regulations have been




restructured along these lines.




      Furthermore, those facilities which will be granted interim




status under these regulations will be existing facilities which




were designed (in most instances) before the proposed regulations




were promulgated.  Thus, establishing equivalence with landfill



standards after the fact is both difficult and impractical.




      Therefore, the Agency has decided to drop the requirement




of equivalence to landfill criteria as a condition for closing a




surface impoundment without removal of the waste.




      Instead, the present regulations allow more flexibility




than the proposed interim status standards.  To avoid closing as




a landfill, the owner or operator must remove all hazardous wastes




and residues from the surface impoundment, including (unless he




can show that they are non-hazardous) the impoundment liner (if

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any) and underlying and surrounding contaminated soil.  However/



the choice whether to remove these materials or to close as a



landfill is up to the owner or operator  (subject to the approval



of the Regional Administrator under Subpart G).  In addition, the



owner or operator may choose to remove only part of the hazardous



materials and then close as a landfill.



      Finally, a comment suggested that  the regulation should



allow for gradual closure of a surface impoundment by diking off



a section at a time.  The Agency believes that the regulation



does not preclude such a procedure as long as the specific closure



plans are approved by the Agency.



2.    Feasibility and Desirability of Waste Removal



      The Agency does not agree that removal of waste and waste



residuals would pose a greater environmental threat than permanent



disposal within the impoundment.  The probablity of ground water



contamination if wastes remain in an impoundment is evident from



the damage cases presented earlier in this document.  On the



other hand, hazardous waste and waste residuals can be removed



from surface impoundments without significant environmental risk.



A number of existing surface impoundments are being periodically



dredged  (e.g., settled sludge removed) without known environmental



problems.  This, for example, is a commonly used operational



practice for flow-through settling ponds, which would otherwise



quickly  lose their capacity if the periodic sludge removal were



not performed.



      The comment that waste removal may require a large amount



of time  and money is valid in some situations.  However, there should

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be cases where waste removal is more feasible and cost-effective




than leaving the wastes in place with closure as a landfill.  For




those circumstances where complete removal of the wastes is




prohibitively expensive, the regulations provide the owner or




operator with alternatives such as partial removal of wastes and




closure as a landfill or leaving the wastes in place and closing




as a landfill.  The purpose of this flexible approach is to




provide the owner or operator with a wide choice of alternatives,




while still assuring adequate protection of human health and the




environment from any hazardous wastes remaining in the impoundment




after closure.  The owner or operator's choice of closure plans




may depend in substantial part on just how much material will




have to be removed from the impoundment.  The determination of




the amount of material to be removed will be a function of the




amount and mobility of the remaining hazardous wastes,  judgments




as to the precise nature of the cover materials needed, and the




post-closure care required.  The determinations for closure are



ultimately subject to the approval of the Regional Administrator.




      Similarly, the response to the specific comment on metals




mining and processing is largely the same.  However, the points




made in that comment regarding damage to the liner and structural




integrity of the impoundment appear not to be relevant.  Since the




waste is being removed, the need for maintaining the containment




system no longer exists.  The liner itself, particularly a soil



liner, may be contaminated with hazardous wastes, making removal




desirable.
                                75"

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      The commenter, who suggested that crude oil should be



exempted from the surface impoundment regulations regarding waste



removal, argues that crude oil worked into the soil should fall



under the land treatment regulations.  Since waste crude oil is



not listed as a hazardous waste in Subpart A of the final



regulation, it would not be covered by these regulations unless



it fails one of the criteria of ignitability, reactivity, corrosivity,



or toxicity.  However, if it is a hazardous waste, the Agency is



skeptical that working it into the soil of a surface impoundment



is an acceptable practice.  It is conceivable that a permit



could be obtained to operate a closed surface impoundment



as a land treatment facility.  Only under those circumstances



could this commenter's suggestion be carried out.  This approach



could be suggested in the owner/operator's closure plan.  If the



approach is sufficiently protective, it would be viewed favorably-



      Although it was not specifically questioned by any of the



commenters, the Agency believes that it is necessary to clarify



the term "waste residues" in the proposed regulation.  The Agency



intended waste residues to include those slimes, sludges, and



similar solids and semi-solids that may accumulate at the bottom



of an impoundment containing liquid wastes.  These residuals may



contain very high concentrations of hazardous materials, and in



some cases should be removed and disposed of as a hazardous

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waste along with the other hazardous wastes contained in the




impoundment.




      Consideration of how to specifically define waste residues




also raised the issue to the Agency of hazardous constituents of




waste that may migrate into a soil liner or natural in-place




soil.  Depending on the permeability of such soil, it could, at




least in its upper portions, become highly contaminated with




hazardous constituents.  Contamination could extend through the




soil to ground water in some instances.



      Such contaminated soil, particularly the highly contaminated




portions, could present a significant danger to public health and




the environment in some instances if left in place and/or not



shielded from infiltration of water.  Movement of water through




the soil could cause leaching of contaminants.  The probability




of ground water or surface water contamination actually occurring



from such contaminated soil depends on a variety of site specific




factors.




      The Agency believes that such factors should be considered




by the owner or operator determining whether a portion of the




soil liner or in-place soil should be removed and disposed along




with the hazardous wastes and waste residues.  This would also



become an important aspect for consideration by the Regional




Administrator in the evaluation of the closure plan.




      Since the potential for leaching of contaminants from



contaminated soil or waste residuals depends on the infiltration




of moisture,  that potential can be reduced or eliminated by




appropriate capping of the site with a cover to minimize
                                 •77

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infiltration.  The Agency believes that this option should be



considered in the development of a closure plan.



      In view of all of the above comments and considerations,



the Agency decided to modify its requirements regarding total



removal of wastes or total removal of hazardous wastes from a



surface impoundment as a closure option.



      The new approach affords the flexibility of considering



each facility on a case-by-case basis.  In evaluating each closure



plan the Regional Administrator will consider a number of factors



specific to that site which define the adequacy of the proposed



closure procedures to protect human health and the environment.



3.    Filling of an Impoundment Where Waste Has Been Removed



      Upon review of the comments which questioned the need for



fill in an impoundment where all the wastes have been removed,



EPA has re-evaluated its position.  The Agency believes that if



all the wastes have been removed, any subsequent addition of fill



material will not provide any greater protection of human health



and the environment.  As a result, the requirement for adding



fill material has been dropped in these regulations for impoundment



which has had all of the hazardous wastes removed.  Furthermore,



the Agency agrees with the comments regarding the requirement



that "inert" fill material be used.  Few native soils are truly



inert, and the requirement was probably overrestrictive.



      Comments also suggested that dikes could be pushed in and



leveled after waste removal.  The final regulations do not preclude



this.  The pushing in of dikes may be addressed in the closure



plan and/or may be required by the Regional Administrator



depending upon the site-specific situation.






                                   78

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      In summary, the Agency has adopted a more flexible closure



regulation which provides a greater opportunity for consideration



of site specific factors in designing a closure plan which will



be protective of public health and the environment.



      These regulations provide flexibility for closure requirements



and allow the wastes to be left in place.  The owner or operator



may elect to remove standing liquids, waste and waste residues,



the liner (if any) and underlying and surrounding contaminated



soil.  If any of the above constituents remain in the impoundment,



the owner or operator must both close the impoundment and provide



post-closure care as for a landfill.  The closure requirements will



ultimately depend upon the quantity and characteristics of the



hazardous constituents remaining in the impoundment.  The major



requirement for an impoundment to be closed as a landfill is that



the waste which remains in the impoundment must be capable of



supporting the final cover.  This may be accomplished by a



combination of removing wastes (e.g., the liquid portion) and



treating the residues (e.g., further dewatering, evaporation, or



chemically stablizing or solidifying the residues).



      It should be noted that the closure and post-closure



requirements are interim final.  The reason for this is because



the landfill closure requirements have changed significantly from



the proposed interim status requirements.  Inasmuch as the surface



impoundment closure requirements defer in part to the landfill



closure requirements, the Agency believes it is only appropriate



to indicate that these closure requirements are interim final.



This will provide an opportunity for the Agency to receive and



review comments on the closure requirements.






                                  71

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D.    Final Regulatory Language




      §265.228 Closure and Post-Closure  [Interim Final]




      (a)  At closure, the owner or operator may elect to remove




from the impoundment:




           (1)  Standing liquids;




           (2)  Waste and waste residues;




           (3)  The  liner, if any; and



           (4)  Underlying and surrounding  contaminated soil.




      (b)  If the owner or operator removes all the  impoundment




materials  in paragraph  (a) of this Section, or can demonstrate




under §261.3(f)  of  this Chapter that none  of the materials




listed  in  paragraph (a) of this Section  remaining at any stage




of  removal are hazardous wastes, the impoundment is  not further




subject to the requirements of the Part.




[Comment:  At closure,  as throughout the operating period,  unless




the owner  or operator  can demonstrate,  in  accordance with  §261.3(c)  or (d]




of  this Chapter, that  any solid waste  removed  from the surface




impoundment  is not  a hazardous waste,  he becomes a generator  of




hazardous  waste  and must manage  it in  accordance with all  applicable




requirements of  Parts  262,  263,  and  265  of this Chapter.   The




surface impoundment may be  subject to  Part 257 of this Chapter




even if it is  not  subject to  this  Part.]



       (c)   If  the  owner or  operator  does not  remove  all the




impoundment  materials  in paragraph  (a) of  this Section, or does




not make the demonstration  in paragraph (b) of this  Section,  he




must close the  impoundment  and provide post-closure  care as for  a

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landfill under Subpart G and §265.310.  If necessary,  to support



the final cover specified in the approved closure plan,  the owner



or operator must treat remaining liquids, residues,  and soils by



removal of liquids, drying,  or other means.



[Comment:  The closure requirements under §265.310 will vary with



the amount and nature of the residue remaining,  if any,  and the



degree of contamination of the underlying and surrounding soil.



Section 265.117(d) also permits the Regional Administrator to




vary post-closure requirements.]
                                 s\

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10.   ISSUE;  DEFINITION OF LINER



A.    Proposed Definition



      As proposed,  "liner" means a  layer of emplaced materials



beneath, a surface  impoundment or landfill which  serves to restrict



the escape of waste or  its constituents from  the  impoundment or




landfill.



B.    Comments on Proposed Definition



      1.  It is  not clear whether requirements  using this term



          would  result  in the appropriate barrier on the sides as



          well as the bottom of the impoundments  and landfills.



          Revised definition to read:   "liner"  means a  layer of



          emplaced  materials  (i) beneath or on  any of the sides



          of a surface  impoundment  or  landfill,  (ii) on the sides



          or bottom of  a surface impoundment  or landfill,  (iii)  on



          any of the  sides of a surface impoundment or  landfill...to



          restrict  the  escape of waste or  its constituents from



          the impoundment or  landfill.



       2.  Definition  is inadequate.  "Beneath"  should be expanded



          to  include  sides  in all  cases and top in others.  A



          liner  may encapsulate an  entire  disposal cell.



       3.   "Liner"  is  not defined adequately.  By referring to



           §250.45-3(c)(3),  one  can  see that a liner is  not confined



          to  "...beneath a  surface  impoundment...."



       4.   "Liner"  should be  defined to include  emplaced materials



          inside storage tanks,  and containers, in accordance




          with  §250.44(h).
                                     82-

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      5.  The definition should be broadened by specifying that


          it includes not only emplaced materials, but naturally


          occurring materials which may be found beneath a surface


          impoundment or landfill.  The permeability requirement


          could in many cases be satisfied by naturally occurring


          materials which are already in place.


      6.  Definition should be modified to allow the acceptance


          of in-place materials provided the permeability rate is

                      -7
          less than 10   cm/sec.


      7.  Modify definition to read "... continuous layer...,"


          and "...restrict the downward and lateral escape...."


C.    Response to Comments


      Liners are not required for interim status surface


impoundments.  The Agency believes that most existing surface


impoundments are not lined, and it would be impracticable to


require such.  Therefore, there is no need to define "liner" in


the interim status standard for surface impoundments.  As a


result, no response is required.


11.   NEW DEFINITIONS


      A definition of "dike" was not included in the proposed regulation


 and no comments were received on this point.  An understanding


of the term "dike" is essential for meeting the general operating


requirement for freeboard as well as the containment system


requirements.  Therefore, EPA has defined the term "dike" for


final interim status.  The term "dike" means an embankment ridge


of either natural or man-made materials used to prevent the


movement of liquids, sludges, solids, or other materials.

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                          V. REFERENCES


1.   Surface Impoundments and Their Effects on Groundwater Quality
    In the United States - A Preliminary Survey. EPA,  57019-78-004,
    1978.

2.   The Prevalence of Subsurface Migration of Hazardous Chemical
    Substances at Selected Industrial Waste Land Disposal Sites,
    EPA/5301 SW-6341, Oct. 1977.

3.   Personal communication. H.  Page Fielding, Delaware River
    Basin Commission, to Alice  Giles, Office of Solid  Waste,
    April 1975.

4.   New Jersey Department of Environmental Protection  files,
    Trenton, New Jersey.

5.   Bureau of Water  Quality Management  files, Pennsylvania
    Department of Environmental Resourcs, Harrisburg,  Pennsylvania.

6.   New Jersey Department of Environmental Protection  files,
    Trenton, New Jersey.

7-   Tracy, J.V., and N.P. Dion. Evaluation of Groundwater
    Contamination from  Cleaning Explosive-Projectile Casings  at
    the Bangor Annex, Kitsap County, Washington, Phase II.  U.S.
    Geological Survey,  Water-Resources  Investigations  62-75,
    Open-File Report, 1976. p.  44.

8.  Personal communication.  Edward Simmons, Harrisburg Regional Solid
    Waste Director,  Bureau of  Land Protection, Pennsylvania Department
    of Environmental Resources, to Robert Weems and Alice Giles,
    Office of Solid  Waste,  Spring, 1975.

9.  Personal communication.  Edward Simmons, Harrisburg Regional
    Solid Waste Director, Bureau of Land  Protection, Pennsylvania
    Department of Environmental Resources, to Robert Weems and Alice
    Giles, Office of Solid Waste,  Spring  1975.

10. U.S. Environmental  Protection Agency, Office of Solid Waste.
    Disposal of Hazardous Waste; Report to Congress.

11. Ibid.

12. Ibid.

13. Ibid.

14. U.S. Environmental  Protection  Agency, Office of Solid Waste,
    Preliminary Assessment  of  Cleanup  Costs  for National Hazardous
    Waste  Problems"  1979.

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15. U.S. Environmental Protection  Agency,  Office of Solid Waste
    internal file.

16. Texas Water Quality Board,  Industrial  Solid Waste Management,
    Technical Guide No. 4  (Ponds and  Lagoons) .

17. Pennsylvania Department of  Environmental  Resources, Solid Waste
    Management Rules and Regulations,  Title 25.

18. Oklahoma State Department of Health, Guidelines for Controlled
    Industrial Waste Surface Disposal  Sites,  Chapter V. Ponds and
    Lagoons.

19. Upgrading Wastewater Stabilization Ponds  to Meet New Discharge
    Standards, pg. 25. Symposium Proceedings  sponsored by Utah Water
    Research Laboratory, College of Engineering,,  Utah State
    University and by EPA, ORD, November 1974.

20. Process Design Manual  for Upgrading Existing Wastewater
    Treatment Plants, U.S. - EPA Technology Transfer,  October 1974.

21. B.C. Liptak:  Environmental Engineer's Handbook, Vol. 1, Water
    Pollution.

22. Stevens Company, sales brochure,  p. 3.

23. State of California, State Water  Resources  Control Board, Waste
    Discharge Requirements for  Nonsewerable Waste  Disposal to Land.
    Disposal Site Design and Operation Information.

24. Wastewater Engineering:  Collection, Treatment,  Disposal.

25. U.S. Environmental Protection  Agency,  Region III,  File on
    Hazardous Waste Damage Cases.

26. South Carolina Department of Health and Environmental Control,
    Hazardous Waste Management  Regulations, R.  61-79.4.

27. New York Department of Environmental Conservation, Solid Waste
    Management Facility, Content Guidelines for Plans and
    Specifications.

28. Oregon  Department of Environmental Quality, Rules Applicable to
    Hazardous Waste Facilities.

29. Damages and Threats Caused by  Hazardous Material Sites, Oil
    and Special Materials  Control  Division, U.S.  Evironmental
    Protection Agency, Washington, D.C., Feb.  1980.

30. Missouri Hazardous Waste Survey Report, Missouri Department
    of Natural Resources,  Jefferson City,  Missouri,  Aug. 1979.

31. Jim Detjen and Jim Adams,  "5 Military  Installations in Kentucky,
    Indiana Have Their  Problems". The Courier-J6urnal, Louisville,
    Kentucky, 1979.

32. Jim Detjen and Jim Adams, "Industrial  Wastewater Leaking from Lagoons
    Can Be  Problem".  The  Courier-Journal,  Louisville, Kentucky, 1979.

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   -Appendix -  Final Regulatory Language
                 Subpart K - Surface Impoundments

§265.220  Applicability

     The regulations in this Subpart apply to owners and operators

of facilities that use surface impoundments to treat, store, or

dispose of hazardous waste, except as  §265.1 provides otherwise.

[§265.221  Reserved]

§265.222  General operating requirements*

     A surface impoundment must maintain enough freeboard to

prevent any overtopping of the dike by overfilling, wave action,

or a storm.  There must be at least 60 centimeters  (2 feet) of

freeboard.

[Comment:  Any point source discharge  from a surface impoundment

to waters of the United States is subject to the requirements of

Section 402 of the Clean Water Act, as amended.  Spills may be

subj'ect to Section 311 of that Act.]

§265.223  Containment system*

     All earthen dikes must have a protective cover, such as

grass, shale, or rock, to minimize wind and water  erosion and to

preserve their structural integrity.

[§265.224  Reserved]

§265.225  Waste analysis and trial tests*

     In addition to the waste analyses required by §265.13,"

whenever a surface impoundment is to be used to:

     (1)  Chemically treat a hazardous waste which is substantially

     different from waste previously treated in that impoundment; or
                           8C.

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     (2)  Chemically treat hazardous waste with a substantially



     different process than any previously used in that impoundment;



the owner or operator must, before treating the different waste



or using the different process:



     (1)  Conduct waste analyses and trial treatment



     tests (e.g., bench scale or pilot plant scale tests); or



     (2)  Obtain written, documented information on similar



     treatment of similar waste under similar operating conditions;



to show that this treatment will comply with §265.17(b).



[Comment;  As required by §265.13,  the waste analysis plan must



include analyses needed to comply with §§265.229 and 265.230.



As required by §265.73, the owner or operator must place the



results from each waste analysis and trial test, or the documented



information,  in the operating record of the facility.]



§265.226  Inspections



     The owner or operator must inspect:



     (1)  The freeboard level at least once each operating day



     to ensure compliance with §265.222, and



     (2) The surface impoundment, including dikes and vegetation



     surrounding the dike, at least once a week to detect any



     leaks,  deterioration, or failures in the impoundment.



[Comment;  As required by §265.15(c), the owner or operator must



remedy any deterioration or malfunction he finds.]



[§265.227  Reserved]
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§265.228  Closure and post-closure [Interim Final]



     (a)  At closure/ the owner or operator may elect to remove from*



the impoundment:



     (1)  Standing liquids;



     (2)  Waste and waste residues;



     (3)  The liner/ if any; and



     (4)  Underlying and surrounding contaminated soil.



     (b)  If the owner or operator removes all the impoundment



materials in paragraph (a) of this Section, or can demonstrate



under §261.3(f) of this Chapter that none of the materials listed



in paragraph (a) of this Section remaining at any stage of



removal are hazardous wastes, the impoundment is not further subject



to the requirements of this Part.



CComment;  At closure, as- throughout the operating period, unless



the owner or operator can demonstrate, in accordance with §26l.3(c)



or (d) of this Chapter, that any solid waste removed from the surfao



impoundment is not a hazardous waste, he becomes a generator of



hazardous waste and must manage it in accordance with all appli-



cable requirements of Parts 262, 263, and 265 of this Chapter.  The



surface impoundment may be subject to Part 257 of this Chapter even



if it is not subject to this Part.]



     (c)  If the owner or operator does not remove all the impound-



ment materials in paragraph (a) of this Section, or does not make



the demonstration in paragraph  (b) of this Section, he must close



the impoundment and provide post-closure care as for a landfill

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under Subpart G and §265.310.  If necessary to support the final



cover specified in the approved closure plan, the owner or



operator must treat remaining liquids, residues, and soils by



removal of liquids, drying, or other means.



[Comment;  The closure requirements under §265.310 will vary with



the amount and nature of the residue remaining, if any, and the



degree of contamination of the underlying and surrounding soil.



Section 265.117(d) allows the Regional Administrator to vary



post-closure care requirements.]



§265.229  Special requirements for ignitable or reactive waste*



     Ignitable or reactive waste must not be placed in a surface



impoundment, unless:



     (1)  The waste is treated,  rendered, or mixed before or



     immediately after placement in the impoundment so that (i)



     the resulting waste, mixture,  or dissolution of material no



     longer meets the definition of ignitable or reactive waste



     under §§261.21 or 261.23 of this Chapter, and (ii) §265.17(b)



     is complied with; or



     (2)  The surface impoundment is used solely for emergencies.



§265.230  Special requirements for incompatible wastes*



     Incompatible wastes, or incompatible wastes and materials,



(see Appendix V for examples) must not be placed in the same



surface impoundment, unless §265.17(b) is complied with.



[§§265.231 - 265.249 Reserved]
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