BACKGROUND DOCUMENT


   RESOURCE  CONSERVATION AND RECOVERY ACT

  SUBTITLE C -   HAZARDOUS WASTE MANAGEMENT
SECTION 3001  -  IDENTIFICATION AND  LISTING OF
                HAZARDOUS WASTE
   §261.22  -  Characteristic of  Corrosivity
                                            MAY 2,  1980
    U.S. ENVIRONMENTAL PROTECTION  AGENCY
           OFFICE  OF  SOLID WASTE

-------
                      Table  of  Contents                      '<-'
                                                             >;.2.4401
  I.  Introduction

 II.  Proposed Regulations

III.  Rationale for the Proposed Regulations
      A.  Rationale for Proposing  a  Corrosiveness  Characteristic
      B.  Rationale for Proposing  Definition  of  Corrosiveness

 IV.  Test Methods
      A.  pH
      B.  Metal Corrosion

  V.  Comments on the Proposed Regulations

 VI.  Promulgated Regulation
Appendix A - Corrosiveness -  State  Identfication Criteria

Appendix B - Examples in which Corrosive Wastes  Caused Tissue
             Damage

Appendix C - Case Histories of Accidents Caused  by  Mixing
             of Incompatable  Wastes

Appendix D - Reactions Between Acids  or  Bases  and Other
             Substances - Possible  Adverse  Consequences

Appendix E - Examples of Corrosive  Wastes Caus-lng^-Damage
             to Aquatic Life

-------
 I.     Introduction



       Subtitle C of the  Solid Waste  Disposal Act, as amended by



 the  Resource  Conservation  and Recovery £<-t of  1976 creates a



 comprehensive "cradle-to-grave" management control system for



 the  disposal  of hazardous  waste designed to protect public



 health and the environment from the  improper disposal of



 such waste.   Section 3001  of that Subtitle requires EPA to



 identify the  characteristics of and  list hazardous wastes.



 Wastes identified or listed as hazardous will  be included in



 the  management control system created by Sections 3002-3006



 and  3010.  Wastes not identified or  listed will be subject to



 the  requirements  for non-hazardous waste imposed by the States



 under  Subtitle D.   The Agency has determined that corrosiveness,



 the  property  that makes a  substance  capable of dissolving



material with which it comes in contact, is a  hazardous



 characteristic because improperly managed corrosive wastes



pose a substantial  present or potential danger to human health



and  the environment.  The purpose of this document is to



explain the Agency's  definition of corrosive waste, to discuss



the  comments  received on the Agency's proposed definition of



corrosive waste and  to discuss the changes made in response



to those comments.

-------
II.   Proposed Regulation



      §250.13(b) Corrosive waste.



      (1)  Definition  -  A solid waste is a hazardous waste



      if a representative sample of the waste:



           (i)   Is aqueous and has a pH less than or equal



           to 3 or greater than or equal to 12 as determined



           by the method cited below or an equivalent method.



           (ii)  Corrodes steel (SAE 1020) at a rate greater



           than 0.250  inch per year at a test temperature of



           130°F as determined by the method cited below or an



           equivalent method.



      (2)  Identification method.



           (i)    pH shall be determined using a pH meter,  following



           the protocol-specified in the "Manual of Methods for



           Chemical Analysis of Water and Wastes"  (EPA



           625-16-74 003).



           (ii)   Rate of metal corrosion shall be determined



           using the protocol  specified in NACE (National



           Association of Corrosion Engineers)  Standard



           TM-01-69.

-------
 Ill.   Rationale for  the  Proposed  Regulation


       A.   Rationale  for  Proposing a  Corrosiveness Characteristic


           Corrosiveness  was chosen as a characteristic of


 hazardous  waste because  improperly managed corrosive wastes


 present a  danger to  human health  and the environment.


 Corrosion  involves the destruction of both animate and inanimate


 surfaces.   For  regulatory purposes,  the Agency believes that


 hazards associated with  each must be considered.  Wastes


 capable of destroying animate surfaces may injure human
                                                            «

 tissue while wastes  capable of corroding inanimate surfaces


 may destroy containers holding hazardous substances, thereby


 enhancing  the introduction of contaminants into the environment.


 In addition, corrosive wastes can react with other wastes to


 generate additional hazardous substances or dangerous amounts of


heat.  A number of States identify Corrosiveness as a hazardous


waste property  in their hazardous waste regulations.  These


 State regulations are indexed in  Appendix A.


      B.    Rationale  for Proposed  Definition of Corrosiveness


           1.  Introduction


              The Agency has chosen pH as one indicator of


Corrosiveness because the hydrogen ion concentration, which


pH measures, is causally related  to many of the hazards


associated with Corrosiveness (a thorough discussion of the con-


cept of pH may be found in Reference 1).  Application of a character-


istic based on pH encompasses the following hazards:


              o  Harm to human tissue.   Wastes exhibiting very


              high or low pH levels may cause harm to transporters

-------
               and other persons coming into contact with the



               waste.



               o  Solubilization of toxic constituents of



               solid waste resulting in migration to groundwater.



               Unregulated disposal of wastes with very high



               or low pH levels may contribute to the solubiliza-



               tion and migration of toxic constituents to



               groundwater/ thereby threatening the health of



             .  those who use groundwater as a source of drinking



               water.



               o  Dangerous chemical reactions.  Co-disposal of



               wastes with high or low pH levels may produce



               reactions resulting in dangerous heat production



               or generation of toxic fumes.



               o  Harm to aquatic life.  Improper disposal of



               wastes exhibiting either high or low pH levels



               may alter the pH of surface waters to the



               detriment of aquatic organisms.



     The Agency has chosen metal corrosion rate as another



expression of  corrosiveness because the metal  corrosion  rate



indicates the  ability of a corrosive waste to  eat through its



container and  escape to the surrounding area where it may .



react with nearby wastes to release hazardous  substances



or corrode other containers holding hazardous  wastes.  Available



information reveals that hazardous wastes are  frequently



stored, transported,  or disposed in metal containers.



Application of  a characteristic  based on metal corrosion rate

-------
encompasses  hazards associated with the escape  of  corrosive




wastes  from  their  containers to the surrounding  area.




     The  various hazards covered by the proposed corrosiveness




characteristic  are discussed below in greater detail.




           2.  Effects  of Improper Disposal of Wastes Exhibiting




High or Low  pH  Values




(a)  Injury  to  Humans




     Wastes  exhibiting very high or low pH levels  may  cause




harm to persons who come into contact with the  waste.   Acids




cause tissue  damage by coagulating skin proteins and  forming




acid albuminates.   Strong bases or alkalis,  on  the other




hand, exert  chemical action by dissolving skin  proteins,




combining  with  cutaneous fats and severely damaging keratin.




Alkali burns  tend  to be progressive due to the  formation  of




soluble alkaline proteinates and are therefore  more dangerous




than acid  burns which  may be limited by the  insolubility  of




acid albuminates.   In  each type of burn, the hydrogen  ion




and hydroxyl  ion concentration is a factor related to  injury.(2)




Studies indicate that  pH extremes above 11.5 and below 2.5




generally  are not  tolerated by human corneal (eye)  tissue (3).




     Substances most frequently implicated in damage  to human




tissue in  occupational settings are sulfuric, hydrochloric,




hydrofluoric, nitric,  acetic, carbolic, formic  and oxalic




acids and  ammonia,  caustic soda, and caustic potash (4,5).




EPA files  contain  descriptions of several incidents in which




contact with  corrosive wastes resulted in tissue damage  (6).




Three incidents are described in Appendix B.




                               5

-------
 (b)  Solubilization of Toxic Contaminants



      Low or high pH levels significantly promote the  solubili—



 zation of certain toxic substances such as heavy metals.



 Once solubilized, these hazardous substances can migrate  to



 a groundwater body where, under proper conditions,  they can



 move great distances without significant attenuation  of
                      i


 toxicity.  Since approximately half the population  of the



 United States depends on groundwater as a source of drinking



 water,  this enhanced migration of toxic constituents  warrants



 serious concern (7).   A study of 50 land disposal sites in



 which industrial wastes had been placed revealed that sub-surface



 migration of hazardous substances is prevalent.   Migration



 of  toxic  heavy metals was confirmed at 30 of the sites? at



 26  of the sites levels in excess of EPA drinking water standards



 were  discovered (8) .   Damage resulting from contamination of



 groundwater by toxic inorganic substances is well documented.



 Reference 6 contains  many examples  of injury to  human "health



 and the environment  attributable to contaminated groundwater.



      The  tendency of  toxic waste constituents to solubilize



 in  response to increased or decreased pH levels  is  illustrated



by  the  theoretical solubilities  of  heavy metal compounds  in



aqueous solutions at  various pH  values.   For instance,



calculations  demonstrate  that a  drop in  pH from  4.0 to 2.0



should  increase the  solubility of red mercury oxide (HgO)



or of chromium hydroxide  (Cr(OH)3)  in water  approximately



one hundred times (9).   In general,  compounds of mercury  tend



to solubilize in an acidic environment while chromium, cadnium,



                               6

-------
 lead and silver compounds may be soluble in either acidic  or



 alkaline media.,  Compounds of arsenic and selenium solubilize



 more readily in an alkaline environment.  (9,10,11)



      Because the solubilization of waste stream components is



 a complex phenomenon dependent upon factors such as the  ionic



 strength of the medium,  the oxidation potential,  and  the presence



 of complexing and chelating agents and available anions, the



 above theoretical solubilities—which are applicable  to  pure



 compounds in simple systems—cannot readily be  extrapolated



 to complex waste systems.   However,  these figures clearly



 reveal trends in the relationship  between pH and solubility.



 Thus,  although limits which precisely define the low  or  high



 pH values at which solubilization  of the  various  heavy metal



 compounds occurs in all  wastes cannot be  established  in  reliance



 on these  figures,  in general,  there is greater  potential for



 solubilization as  pH values approach the  lower  and  upper ends



 of the scale.



 (c)  Dangerous chemical  reactions



     Co-disposal of incompatible wastes may lead to the



 following harmful  reactions:   1.  heat generation,  2.  fire,



 3.  explosion,  4.   formation of flammable gases,  5.   volatili-



 zation of toxic  or  flammable substances,  6.   formation of



 substances of  greater toxicity, 7.   formation of  compounds



 sensitive to shock  and friction, 8.   pressurization in closed



vessels,  9.  formation of toxic fumes, 10.   dispersal of



toxic  dusts, mists  and particles, and  11.  violent polymeri-



zation  (12).   Improper disposal of wastes  exhibiting high  or



                               7

-------
Intentionally Blank
      -8-

-------
 low pH levels is often associated with these adverse conse-



 quences.  Toxic and flammable gases/  for instance,  may



 be generated when cyanides or sulfides are mixed with acids



 (13).   Violent chemical reactions can occur when strong acids



 are mixed with strong bases.   Appendix C contains case



 histories documenting damage  to human health,  the environment



 and property caused by mixing acidic  or caustic  wastes with



 other  wastes.   Appendix D lists possible adverse consequences



 resulting from reactions between acids or bases  and other



 classes of compounds.



     It is difficult to establish an  exact pH value at which



 wastes of varying composition pose a  hazard,  but certainly



 the tendency to cause  harmful chemical reactions becomes more



 pronounced at the extremes of the pH  scale.   By  any estimation,



 highly acidic  or highly alkaline liquid wastes have the potential



 to  cause chemical reactions which can have an  adverse effect on



 human  health and the environment.



 (d)  Injury to aquatic life



     Improper  disposal of wastes exhibiting high or low pH



 may alter  the  pH levels of surface  waters,  resulting in harm



 to  aquatic life.   Studies  indicate  that  the optimum pH range



 for freshwater fish  is 6.5 -  9.0;  an  increase  or decrease of



 2 pH units beyond  the  optimum causes  severe effects.   Bioassays



 conducted  on the  fathead minnow revealed that  a  generation



maintained in  environments  with pH  values  of 4.5 and  5.2



were deformed  and  exhibited abnormal  behavior.   As  Table 1



shows,  pH  levels of  11.0  or 3.5 are fatal  to all  species of



                               9

-------
 fish.  At pH levels below 3 and above 12,  very few organisms
 are capable of survival (14).
      Addition of wastes exhibiting low or  high pH levels to
 surface waters can also increase the toxicity of substances
 in the water.  Acidification of the water  can result in the
 release of free carbon dioxide in toxic quantities, and a
 drop of about 1.5 pH units can cause a thousand-fold increase
 in the acute toxicity of a metallocyanide  complex (14).  In
 addition,  alteration of the surface water  pH is capable of
 affecting  the productivity of food organisms which fish and
 wildlife need to survive.   Appendix E lists  incidents of
 damage to  aquatic life caused by wastes exhibiting high or
 low pH values (6).
 (e)   EPA' s f ina 1 pH 1 imi't's
      As noted above,  the Agency has chosen pH as one measure
 of  corrosiveness because pH provides an easily-measurable,
 multi-purpose indicator of several potentially hazardous
 conditions.   In its proposed regulation, the Agency defined
 aqueous wastes  with pH levels below 3.0 and  above 12.0 as
being hazardous.   These limits were chosen in an attempt to
balance the  following considerations:   sensitive human tissue
may be  damaged  when contacted with substances exhibiting pH
 levels  below 2.5 or above  11.5?  strongly acidic or basic
conditions significantly enhance the solubilization of toxic
contaminants  and are  an integral  cause  of  dangerous chemical
reactions; aquatic life is  adversely affected where the pH
of the water  is below 6.5 or above 9.0  and is virtually
                               10

-------
non-existent  in  media with pH values below 3.0  and  above




12.0.




     In  response to the proposed pH limits,  a  great  many




comments  were  received advocating the extension of  the




accpetable  pH  range.   A number of commenters  argued  that  the




proposed  upper pH limit of 12.0 would include  waste  lime  and




many lime treated wastes and sludges which generally have a




pH between  12.0  and 12.5 and which can be put  to agricultural




and other beneficial  uses.  Many of these commenters suggested




raising  the upper pH  limit to 12.5 while others suggested




raising  the limit to  13.0.  A number of commenters  argued




that the  proposed lower pH limit of 3.0 would  include many




common and  innocuous  substances such as cola  drinks  which




exhibit  pH  levels of  between 2.0 and 3.0 and  many  industrial




wastewaters prior to  neutralization which also  exhibit low




pH levels.  Many of these commenters suggested  lowering the




pH limit  to 2.0;  others suggested lowering the  limit to 1.5.




     Upon consideration of these comments and  after  further




deliberation,  the Agency has decided to extend  the  range  of




acceptable  pH  levels  by decreasing the lower  limit  from pH




3.0 to 2.0  and increasing the upper limit from  pH  12.0 to




12.5.  With respect to the upper limit, the  Agency  agrees




with the  coramenters that otherwise non-hazardous  lime stabilized




sludges  and wastes  should not be designated  as  hazardous.




Accordingly, the  Agency has adjusted the upper  limit to pH




12.5 to exclude  such  wastes from the system.   Raising the
                               11

-------
        TABLE —.1.-—A Summary of Some Effects of pH on
            Freshwater Fish and Other Aquatic Organisms 8
                                                KMWiefelS
11.5-1J.J.
11.0-11.5.
               ^e odfc rlej (Tridiocteri) tOTrt ktrt emerpsa reduced.
               Rigid* tetbilU it species ol fob.
 1C.MO.S...


 1.5-10.8...


 J.W.S


 LS-S.6

 I.M.5
 7.M.I....

 t. 5-7.0




 f.M.J .....



 5. 5-t.O .....



 i. C-5.5 .....
4.5-5.0
4.M.5
I.S-4.0
J.C-J.5
                leratnX i»d pike. UUal to some stonefies (Pletoplen) ind dratonffes (OdorataX ddds
                fly emefputa reduced.
           .   Withstood by almonds for short periods but eventually leUal  Eicwds tolerance ef ttwpBS
              (Lepomisiucrochinn)indpTo«ibly  jcldfisb. Some typial stoAefliesindmiyfiet(£pa*Mn)
                sanin witt reduced imervsna.
           .   Uthii to aliwids orer  i orobnpd period ol b'ne ind w viable fishery for coldwitor species.
                Reduces popabb'oas ol wirmwitor fish sad mty be hmilol to development stops, tntu
                reduced emapflct of some slortef&cs.
           .   likely to be tarmlol to almonids ind percb (Pera) H present lor I considerable knfth ef tin*
                ind w mbk fishery lor coldwiter species. Reduced popibtjpni ol wirmweter Ssb. Can I raid
                these lenb.
           .   Approaches tofcnnce limit ol SOIM almonids, whiteftsh (Ccnfonus), catfish (Icbbridae), ud
                perch. Anidrd by pJdfish. No ippirenl eftects on  inrerttbntes.
              Moblity ol art sperm reduced. Pirb'il mortality ol burbot (Uti loll) en*.
            F*ll rah production. No known harmful eflects on idult or immature fish, but 7.0 a nor  low Soil
               lor  Gimnuras reproduction ind perhips for some other cmticeins.
              Not kettal to frsh unless hury mttils or cyanides thit irt more tnic it tow pH ire present.
               Generally III! fish production, but  lor tithead  minnow (Pimeprales promebs). frequency  el
               ssiwnitf ind number ol etp ire somewhat reduced. Inrtrtebnlci eicept mntacnu nbbvtry
               Dormil. incrwfinj common ocairrence ol monusU. Micrgorpniims, ilpe. ind fcfber pbits
             Unliki ly to be tout to fisb unless fret arbon dioiide is present in emss ol 100 ppm. Good «ujbc
               papubtions with nried species an esist with some eucptions. Riprodurtort ol Gimmaras lad
               Diphnii primtod, perhips other crustaoins. Agiubc pbnts ind rmooorpniuns rebbrely
               normal esctpt lunfi Iregwnl
             Eistern brook trout (Silreinus lontinans) surrin it over pH 5i Rtinbow trout (Silno ptrdneri)
               do not OBOT. It uturil  situiboos,  small popubbon ol rebbnh; lew species of fist an be
               lound. Growth rate ol carp reduced. Spiwninf ol litheid minnow sitmfianUy reduced. Molfesfc]
               rare.
             Very restricted  tlsh popubbons but not  lethal to iny fish species onless CO; ii hifh (orer 25 ppoX
               or water eonlairti iron alts. Mfy be  Mthil to nil lid brae ol sensitive fish species. Prrmitt
               soawn'nt of littiad minnow. Benthic inrerlebrates moderately dinrst, with ceraii btact fta
               (SimDEidat).miyflies(Ephemerelli), stonefliM.itdniidps(Chironomidii)presatinaMiben.
               UUal to olhet invertebrates such is the mayfly. Bicteriil speciis diversity decrnsed; yeasti
               ind snltw ind iron bactorii (Thiobidllui-FinobiBllin) common. Alpe totonibrj dime and
               hi(hef pujets wiH pow.           ~'~~~                             •     '
             Ho viable  fisher; an be maintained. Likely to be leUal to erjs ind fry ol salmonids. A satmmid
               popubbon could  not reproduce. Hirmlul, bot not Mcnarily lethil to carp. Adut brow* troit
               (Salmo trctta) an survive in pell witen. Bentbic fiuiu restricted, mar flits reduced. UUal b
               several typial stancftcs.  Inhibits emerpme of certain caddil fly, stonefry, and Teidp brne.
               Otitonu are dominant ilpe.
             Fish popubrb'ons f roiled: only i lew specie! survive. Perth, some coarse fish, and pike on ucf-
               nite to this pM. bit only pike reproduce. Lethal to liUtead minnow. Some caddis ties ind dntoa-
               fles fcond in such  habiUts; certain  midps domirarrl Flora restricted.
             Uttal to almonids ind bluefllls. IJmil ol tolerance ol  punkimeed (Upomis  libbosus). perch,
               pike, ind some coirse fish. ATI flora ind IIUM severer; restricted in number ol species. Cattiil
               (Typha) is only common hif h« plant.
             Onikety that i*y tsh cae surrin lor more than I lew noun. A few kinds of irvrrtcbnta such as
              certain midps aod alderfies, aid I lew species of arpe nay be lound it this pH raep ard tower

-------
upper  limit  to pH 12.5 should not compromise  protection of




human  health.   Although eye tissue  is damaged  when  the pH is




above  11.5,  normal skin tissue is clearly  less  sensitive than




eye  tissue.   Consequently, increasing the  upper pH  limit to




12.5 should  not significantly increase  rhe likelihood of




damage  to  skin.  Also, taking into  account the  many factors




that might influence heavy metal solubility  and causation of




harmful  chemical reactions, an increase  of 0.5  pH unit is not




expected  to  significantly compromise protection against these




two h az ard s.




     With  respect to the lower limit, the  Agency is not




necessarily  in agreement with the comments that such "innocuous"




substances as  cola drinks, if disposed  of  in  a  landfill, will




have only  benign consequences.  Nevertheless,  it  agrees with




the comments  that 2.0 is a better justified  lower pH limit




than 3.0.  The Agency originally chose  3.0 as  its lower limit




based on  tissue damage and heavy metal  solubilizat ion.




Although  studies on corneal tissue  deaoastrated that injury




was sustained  on contact with substances exhibiting pH levels




below 2.5, the proposed pH limit was set at  3.0 to  provide an




extra margin  of protection against  heavy metal  solubilization.




Corneal  tissue,  however, is more sensitive than skin tissue




so reducing  the lower pH limit to 2.0 should  still  allow




adequate  protection against skin injury.   Similiarly, lowering




the pH  limit  to the avowedly highly acidic level  of 2.0




ensures  that  the limit is more likely to encompass  those




wastes which  tend to solubilize toxic substances  and .cause




harmful reactions.




                               15

-------
           3.  Effects of Improper Disposal of Wastes  Capable of



 Corroding Metal.



               Wastes which have the capacity to corrode metals



 can corrode their containers during transportation, storage



 or disposal and escape into the surrounding area.   If such



 corrosive wastes are toxic, their escape can cause  direct



 injury to persons handling the waste and can contaminate the



 environment.  If such wastes exhibit lov or high pH,  their



 escape can result in all the hazards associated with  low or



 high pH,  as discussed above.  Wastes capable of corroding



 metals can also cause the corrosion of other containers in



 which hazardous wastes are stored,  resulting in the leakage



 of those  wastes into the environment.   This unplanned  leakage



 can result in injury to persons handling the wastes and the



 contamination of the environment.



      Metal corrosion is a complex process;  a more detailed



 discussion of its mechanisms may be found in Reference 15.



 Factors which influence the rate of corrosion include tempera-



 ture,  the metal(s)  involved and aeration,  composition and pH



 of  the corrosive medium..  For example,  a corrosive material



 with  a pH less  than 4.0 will cause  iron to  dissolve rapidly



 accompanied  by  evolution of hydrogen.   At pH 4.0-9.5 the



 rate  of attack  is usually low and fairly constant then de-



 creases to a minimum at pH 12.0.  Increases in pH above 12.0



 accelerate dissolution  of the  metal but the corrosion rate is



generally much  less  than that  occurring under acidic conditions.



 In practice,  alkaline solutions  do not  severely damage steel.






                               16

-------
 The presence of dissolved salts  may also accelerate or inhibit



 corrosion;  chloride and  sulfate  ions interfere with development



 of protective films and  contribute  to the breakdown of passive



 films already in existence while calcium and bicarbonate ions



 tend to  limit attack.  The amount of dissolved oxygen is another



 important element because oxygen stimulates the corrosion



 process.   Temperature affects  corrosion by influencing the



 chemical  composition and physical properties of the corrosive



 solution, the nature of  deposits and the behavior of the



 metal.



      The  Department of Transportation has defined a corrosive



 material  as  one  that corrodes  a  low carbon steel (SAE 1020)



 at a severe  rate, i.e.,  greater  than 0.250 inch per year at a



 test temperature of 130"  F (49 CFR  173.240.).  The rate of



 0.250 inch per year was  selected by DOT because experience



 indicated that it represents a severe rate of corrosion.  SAE



 1020 steel was chosen as  a test  material by DOT because it is



 used frequently  in  the manufacture  of steel drums utilized in



 transportation,  and the  130* test temperature was selected



 because that  level  may be encountered during transportation



 of hazardous materials.



      EPA files contain numerous  descriptions of damage



 incidents involving  the use of steel drums to store, transport



 and  dispose of hazardous  waste.   The Agency believes that the



 rate  at which a waste corrodes a material commonly used in



 container construction is  a suitable measure of the hazardous-



ness of the waste.   The DOT metal corrosion standard was






                               17

-------
adopted  because it represents  an  appropriately severe rate of




corrosion,  and the required  test  conditions  adequately reflect




conditions  likely to be encountered  during  transportation,




storage  and disposal of wastes.   An  additional consideration




is the desire of the Agency  to maintain  consistency with




other  regulations whenever practicable.




           4.   Additional Considerations  for  Development of a




Corrosiveness Characteristic.




(a)  Direct Measurement of Tissue Damage




     The  Agency considered proposing  a corrosive  character-




istic  which would directly address tissue damage.   A standard




technique  referenced by Federal agencies  and several States




employs  the application of the suspected  corrosive to the




bare,  intact  skin of albino  rabbits.  The animals  are exposed




for a  specified period of time after  which  an assessment of




tissue damage is  made (16, 17, 18).   Conduction  of the test




requires  maintenance of special facilities  and the use of




skilled  personnel to evaluate the extent  of  injury.   The




Agency believes that performing this  type of testing on each




waste  stream  'would add little to  the  scope  of the  corrosivity




definition  and be unnecessarily burdensome  to many members




of the regulated  community.  For waste disposal  purposes,




relating  tissue damage to an easily measurable characteristic




such as  pH  is the more practical  approach because  the hydrogen




ion or hydroxyl ion  concentration is  related to  the degree of




injury.   The  pH provision will not encompass all  substances




that damage tissue,  but corrosive substances often display




                               18

-------
other hazardous  characteristics that will  bring  them into




the hazardous  waste  net.   For instance,  corrosive  metal




salts such  as  the  arsenicals, chromates  and mercurials proba-




bly will  be  covered  by the toxicity characteristic.




(b)  Acidity and Alkalinity




     During  the  development of these regulations,  it was




suggested  that the corrosiveness characteristic  should




address the  percent  acidity or alkalinity  of  the wastes




in addition  to the pH.   Percent acidity  or alkalinity




provides  an  indication of the capacity of  a liquid waste to




resist a  change  in pH (buffering capacity).   Because the




Agency did not have  adequate information concerning  the




necessity  of addressing acidity and alkalinity  as  a  component




of its hazardous waste definition and had  no  technical basis




upon which to  establish levels of hazard,  comments on this




issue were solicited in the preamble to  the proposed regula-




tions.  A  few  comments  favored adding a.  acid i ty / alkal inity




provision  to the pH  characteristic because it would  provide




useful information for  disposal purposes.  Most  comments,




however,  stated  that addressing acidity  and alkalinity would




not add significantly to  the determination of hazard and




would necessitate  the use of somewhat -more costly  and compli-




cated measurement  techniques than pH alone.




     The Agency  agrees  that the addition of an acidity/alkalinity




determination  to the pH provision of the corrosivity definition




is not necessary.   Although acidity and  alkalinity have some
                               19

-------
bearing  on the manner in which  these  wastes are disposed,




they  add little to the assessment  of  the hazard posed during




transportation, storage and  initial disposal.   Additionally,




because  the ability of a waste  to  retain low or high pH is as




much  a function of its disposal  environment as of its percent




acidity/alkalinity the Agency knows of  no scientifically




valid basis upon which to establish hazardous  threshold levels




of percent acidity/aIkalinity.   Therefore the  Agency has




elected  not to include percent  acidity/aIkalinity in the




definition.




(c)   Corrosiveness of Solids




      The Agency considered making  the pH provision of the




corrosiveness  characteristic  applicable  to  wastes in solid




form  which are capable of forming  aqueous solutions of low




or high  pH once disposed.  Estimates  in  the Agency's possession,




however,  indicate  that approximately  90% of all hazardous




wastes are in  liquid or in semi-liquid  form (19).  The Agency




therefore  solicited comments  in  the preamble to the proposed




regulations on the desirability  of  including solids in the




pH provision of the corrosiveness  characteristic.  The few




comments  that  were received  in  response  to  this inquiry




favored  the inclusion of solids  in  the  corrosiveness definition,




but did  not describe situations  where damage would be likely




to occur  as a  result of improper disposal of such wastes.




     Upon  consideration of these comments,  the Agency has




concluded  that there is no demonstrated  need to address
                               20

-------
solids which  may  become corrosive in its corrosiveness  definition




at this  time.   Liquid  wastes constitute by far the greater




percentage  of hazardous wastes and have a more immediate




potential to  effect  mobilization of toxic substances in the




environment.   Furthermore,  corrosive solids are not as  likely




to cause problems  as liquid wastes because the ability  of  a




solid to form an  aqueous solution of high or low pH varies




with its physical  and  chemical characteristics and the  manage-




ment conditions.   The1RCRA  prohibition against open dumping




coupled  with  the  requirements for proper management of  both




hazardous and non-hazardous wastes under the Section 3004




and 4004 regulations will reduce the risk of damage to  the




environment from  these wastes.  Additionally, some corrosive




solids will probably be subject to the regulations because




they exhibit  other hazardous characteristics, e.g., toxicity.




EPA will continue  to seek additional information on the




hazards  posed by  wastes in  solid form capable of generating •




solutions with  high  or low  pH and will consider specific




regulatory  measures  if the  need for more control becomes




apparent.




IV.   Test  Methods




      A.  pH




          pH  is measured by colorimetric or eleetrometric




means.  Colorimetric techniques have severe limitations which




make them inappropriate for the pH determination of wastes.




They are subject  to  severe  interference from turbidity, color,




high saline content, colloidal matter, free chlorine and
                               21

-------
 various oxidants and  reductants.   In addition, a single




 indicator is often  limited  to  a  relatively narrow pH range.




      An acceptable  method of pH  measurement by electrometric




 technique is described  in Methods  for Analysis of Water and




 Wastes  (EPA-600/4-79-020).   pH  is  determined using either a




 glass  electrode with  a  reference  potential or a combintion




 electrode.   The glass electrode  is  relatively free from most




 types  of interference,  but  may  display impaired response




 under  certain conditions.   The  alkaline error encountered at




 pH values above 10  can  be diminished by using "low sodium




 error"  electrodes.   Ambient  temperature and the temperature




 of the  sample also  influence electrometric measurement.




 The  effect  caused by  the alteration  in electrode output at




 various  temperatures  can be  controlled by  using instruments




 with  a  temperature   compensation  feature.  The variation in




 temperature  of  the   individual samples cannot be controlled;




 therefore,  sample temperature and  pH should be recorded as




 each  sample  is  measured. Other sources  of  interference include




 coatings  of  oily material or particulate matter on the elec-




 trode and reduction of  electrode  life due  to attack by solu-




 tions which  corrode glass.  These  can be minimized by proper




 cleaning  of  the electrode.




     The  form of the substance to be measured should be taken




 into account  during a determination  of  pH.   Blockage of the




 liquid  junction between the salt bridge and the test solution




must be  prevented when  measuring the pH of suspensions, sols
                               22

-------
or gels.   Suspensions  of highly charged sediments  such  as




soils  or  ion  exchange  resins may not give a true pH  reading; •




the solution  should be allowed to settle and the pH  of  the




supernatant measured (20).




     Measurement  of pH is a routine laboratory technique  for




which  a wide  variety of instruments is available.  A precision




of +_ 0.02  pH  unit  and  an accuracy of _+_ 0.05 pH unit  can be




achieved,  but + 0.1 pH unit represents the limit of  accuracy




under  normal  conditions.  Therefore, pH values should be




reported  to the nearest 0.1 pH unit (21).




       B.   Metal Corrosion




           For purposes of hazardous waste definition, EPA




believes  that it  should employ a metal corrosion test which




indicates  the general  corrosion of a metal frequently used  in




the manufacture of  hazardous waste containers.  Coupon




corrosion  testing  is designed for this purpose.  Other




procedures are available to test for special metallurgical




phenomena, but they are more useful in the development  of




specific  container  standards.




     NACE  Standard  TM-01-69 describes a simple immersion  test




to determine  rate  of corrosion.  The procedure is  not completely




standardized  because it was designed to test the suitability




of metals  for a variety of  uses.  Although the standard is




commonly  employed  as a method to detect the corrosiveness of




a solution of known composition on a certain metal,  its flexi-




bility makes  it suitable for determining the corrosiveness




of a mixture  of unknown composition such as a waste.







                              23

-------
      The NACE standard  gives recommended practices for

 sample preparation,  type  of equipment, and test conditions.

 Duplicate metal coupons  are first cleaned and weighed.  The

 solution is placed  in an  apparatus consisting of a flask,  a

 reflux condenser, a  thermowell,  a heating device and an

 appropriate specimen support system.   The preferred minimum

 volume to area ratio is 40  millimeters of solution per square

 centimeter of specimen.   The specimens are exposed to the

 test  solution at a  temperature  of 55eC (130"  F).  Corrosion

 should not be allowed to  proceed  to a point where the original

 specimen size or exposed  area is  drastically  reduced or the

 metal  is perforated.  Aeration  is unnecessary,  and corrosive

 constituents do not need  to  be  replenished because metal

 waste  containers are likely  to  be in  contact  with a limited

 amount  of solution.

     At  the end of the exposure period,  the coupons are

 removed  from the test environment,  then  cleaned and weighed.

 The corrosion rate can be calculated  by  the following equation:


  millimeters per year (mmpy)       =	weight lossx(0.268)
                                                   (area) (t ime)

Weight  loss is in milligrams, area is square  inches of exposed

metal  surface and time is hours exposed

V.   Comments on the Proposed Regulations

       Generally,  comments on  the  proposed  regulation can be

placed  in several broad categories.   The  greatest number of

responses concerned  the proposed  pH limits.   Others addressed
                               24

-------
the establishment  of  a characteristic that would encompass

acidity  and  alkalinity,  solids which form aqueous  solutions

of high  or  low  pH  or  a direct measure of tissue damage.   A

few comments  suggested that neither pH or the metal  corrosion

provision is  appropriate for defining corrosion.

      A.  pH  Limits


              o  The  proposed pH limits are unnecessarily
                 restrictive.

     A  great  many  comments  advocated extending the acceptable

pH range.   These comments  have been fully addressed  above and

need not be  further addressed here.

              o  The  Agency should define the term "aqueous"  waste

     The pH  characteristic  is applicable only to aqueous  waste

because  pH  relates  to  the  hydrogen ion activity in a  solution.

A few comments  suggested that EPA specifically define  "aqueous"

in terms of viscosity  or percent water.  The Agency has not

developed a  specific  definition because of the widely  varying

physical and  chemical  oroperties which influence the  form of

wastes.  Those who  generate,  treat, store or dispose  of a

waste can best determine whether it is in a suitable  form for

pH measurement.

              o  Corrosiveness is not typically defined in
                 terras  of  pH.

     A few  comments stated  that, in the correct technical

sense, corrosion is an  electrochemical reaction between the

environment and a metal  surface; pH is not, therefore, a

standard measure of corrosiveness.   The Agency does not agree

that  the concept of corrosiveness is so limited.  As  stated


                               25

-------
 previously, the Agency  believes that the definition of  a

 corrosive waste should  embrace  both hazards associated  with

 metal  corrosion and hazards  associated with high and low  pH.

 A  waste exhibiting either  a  very high or very low pH may

 corrode the skin tissue  of waste handlers.  pH is also  a

 significant factor in solubilization of heavy metal salts

 which  results in increased mobility of toxic substances in

 the  environment.  In addition  improper disposal of wastes ex-

 hibiting very high or low  pH values can cause dangerous chemical

 reactions in landfills.  Establishing pH limits appears to be

 the  most effective way  to  address the various concerns.

               o  pH limits should address organic wastes.

 Some comments suggested  that the pH limit should address  organic

 wastes.   If an organic waste is  in an aqueous solution  it will

 be subject  to the pH provision.

       B.   Tissue Damage

                o  The regulations should address tissue damage
                   in a more  direct manner.

     Some comments stated  that  the corrosiveness of some

 substances  which damage human tissue will not be adequately

 indicated by a pH measurement.   As discussed previously,  the

Agency  considered adopting the  skin corrosion test referenced

by the  Food and Drug Administration and the Department  of

Transportation,  but concluded that relating tissue damage to

 an easily measurable characteristic such as pH is a more

reasonable  approach for waste disposal purposes.   Not all
                              26

-------
substances  capable  of  damaging human tissue will be encompassed

by the pH provision.   However, wastes may display one or

more of  the  other hazardous  characteristics or possess

qualities which  cause  them to  be listed as hazardous wastes.

Several  comments mentioned the Consumer Product Safety Commission

detergent toxicity  survey  which found a relationship between

pH and corrosiveness to  tissue, but did not find a correlation

strong enough  to use for regulation of detergent products.

The Agency believes that inasmuch as its pH provision addresses

not just tissue  damage but also such things as the solubilizat ion

of toxic materials  and the causation of dangerous chemical

reactions, use of pH as  a  barometer of tissue damage is both

reasonable and justified.

      C.  Acidity/Alkalinity

          o  The regulations should address acidity and
             alkalinity.

     Several comments  addressed the addition of acidity and

alkalinity to  the pH criterion.  These comments have been

fully addressed  above  and  need not be further addressed

here .

      D.  Corrosiveness  of Solids

          o  The regulations should address solids which may
             form aqueous  solutions of high or low pH and solids
             which  are corrosive to metal and human tissue.

     A number  of comments  addressed the desirability of naking

the pH provision of the  corrosiveness characteristic applicable

to solid wastes  as  well  as liquid wastes.  These comments

have been fully  addressed  above and need not be further addressed


                               27

-------
here .




       E.   Metal Corrosion  Provision




           The Agency  received  a  number of comments on the




metal  corrosion provision,  many  of which wanted to inject




management practices  into  the  metal corrosion standard.  Some




commenters felt that  the metal corrosion test should apply




only  to  containerized waste.   Others believed that the test




should be performed on containerized materials using the




specific  material from which the container is made as the




test mat eri al.




           The Agency has made  the  metal  corrosion provision




applicable to non-containerized  wastes because such wastes




are capable of  corroding the containers  of co-disposed wastes.




The Agency has  chosen steel as a test material because steel




is commonly employed in the manufacture  of steel drums and




steel  drums are frequently  used  to store and  dispose of




hazardous waste.   Using the specific material from which a




generator's containers are  made  as the test  material for the




metal  corrosion test would  make  the hazardousness of the




waste  too dependent upon the actual management practices




employed  by the generator.  It must be emphasized that the




metal  corrosion provision  constitutes an attempt to define




which  wastes  are  hazardous  if  improperly managed, that is,




which  wastes  are  hazardous  under  some likely  mismanagement




scenario.   The  definition  is not  an attempt  to set out standards




for proper management; this is accomplished  by the Section




3004 regulations.




                              28

-------
     One  commenter remarked that the 130* test  temperature




specified by  the metal corrosion provision  is too  high.




The Agency picked that temperature to reflect conditions




encountered during transportation of hazardous  wastes  and in




landfills.   Studies show that temperatures  in that range are




encountered in landfills. (22, 23).




     Several  comments were made concerning  the  choice  of




steel  as  a test  material.  One comment  stated that the




corrosion rate of steel is influenced by many factors.  The




Agency  is aware  that corrosion is a complex  phenomenon and




has chosen the NACE test because that test,  by  giving  a




general indication of the ability of a  waste to  corrode  metal,




ably accoraodates the many factors influencing corrosion.  One




comment states that otherwise harmless  wastes such as  salt




water will  corrode steel but provides no information  on  the




corrosion rate of such harmless wastes.  Lacking  such




information,  the Agency is unable to evaluate the  merit  of




this contention.   In any event, the Agency  is convinced  that




any waste which  exhibits as severe a corrosion  rate as 6.35




mm/year must  be  segregated from containers holding other




hazardous wastes during transportation, storage  and disposal.




     One  comment suggested that the metal corrosion test is




unnecessary because steel drums will invariably  corrode  in a




landfill  environment.   The Agency disagrees.  The  metal




corrosion provision is designed to address hazards associated




with transportation,  storage or disposal as well  as hazards
                               29

-------
associated with placing  containerized wastes in landfills.

Furthermore, the Agency  doubts  that the corrosive  influences

found  in a landfill  exert  anything close to the corrosive

effect  exerted by wastes exhibiting a corrosion rate  of 0.250

inch per year.

               o  When  an aqueous  waste, is extremely  thick  or
                  is  not amenable to stirring to obtain homo-
                  geneity,  the  solids should be allowed to
                  settle  and  the  pH of the supernatant measured.

     Some comments suggested  that when an aqueous waste is

extremely thick or is  not  amenable to stirring to obtain

homogeneity (as in the case  of  a  slurry), the solids  should

be allowed to settle and the  pH  test applied to the  supernatant

liquid.   The Agency  finds  this  an acceptable practice to

prevent  interference caused by blocking of the electrode.

      G.   General Comments

               o  Permit writers  should judge the hazard
                  associated with  wastes exhibiting high or
                  low pH levels on a case-by-case basis.

     One  comment suggested that  permit writers should judge

the hazard associated with pH on  a case-by-case basis.  The

purpose  of RCRA Section 3001  is  to define a hazardous vaste

in terms  of physical,  chemical and biological properties.

Actual management standards will  be established under Section

3004.  Regulations promulgated pursuant to Section 3005 will

provide  sufficient flexibility in the permitting process to

accommodate various management methods for hazardous wastes

as long  as those methods protect  human health and the environment
                                30

-------
              Corrosive wastes should not be  classified  as
              hazardous if properly managed.


      Several  comments argued, in effect, that  corrosive wastes

which  are  properly managed or which do not otherwise  fit the

mismanagement scenario envisioned by the corrosiveness

definition should  not be classified as hazardous.   One  comment

stated  that corrosive wastes should be classified  as  hazardous

depending  on  the  containers used.  Other comments  argued that

the definition  should be revised to exclude  wastes  which are

not transported,  stored or disposed with other  wastes.   As

noted' above,  in defining hazardous corrosive waste,  the Agency

has attempted to  reach those wastes which are hazardous if

mismanaged under  some likely mismanagement scenario.  The

purpose of the  definition is to bring such wastes  into

the hazardous waste management system set up by  Sections

3002,  3003, 3004,  and 3005 of the Act -- not to  specify

management  practices.  If management practices  were made part

of the  definition  so that properly managed wastes  were  excluded

from the definition, the effectiveness of the management

system  created  under Sections 3002, 3003, 3004,  and 3005

might well be vitiated,  since properly managed  wastes would

be excluded at  the outset from the continuing supervision and

control provided by the  management system thus  prejudicing

the Agency's  ability to  ensure continued compliance with

these proper  management  practices.  The regulations

under Section 3004 and 3005 will be sufficiently flexible to
                             31

-------
accomodate wastes which are  properly  managed or which otherwise

don't  fit  the mismanagement  scenario  envisioned by the

corrosiveness definition.

     In  a  closely related comment,  one  commenter stated that

since  disposal of liquids in  landfills  is  not permitted,

liquid corrosives do not really  present  a  hazard.   This

argument  is largely circular  because  if  liquid corrosives

were not  classed as hazardous, they could  readily  be disposed

of in  landfill environments.

               o  Specify measurement  of  pH within  +^ 0.5 pH units

     One  comment suggested that  the Agency should  specify

measurement of pH within +_ 0.5 pH units.   Under normal

conditions, pH should be measured to  the nearest 0.1 of a

unit.  Measurement can be made more precisely if necessary.

The Agency sees no reason to  permit measurement within +_ 0.5

pH uni t s .

     Metal Corrosion

               o  NACE Standard TM-01-69  is not completely
                  standardized and permits  variation in a
                  number of test  conditions.

     One comment argued that  the NACE Standard TM-01-69 permits

variation  in  a number of test conditions and that  therefore

the test is not clearly enough defined.  The Agency recognizes

that this  is  the case and, to correct the  problem, has more

clearly  defined the appropriate  test  conditions.  A description

of these conditions is found  in  "Test Methods for  Evaluating

Solid Waste"  SW-846.
                               32

-------
               o   The  generator should be allowed to use  a
                  corrosion rate given in the Corrosion Data
                  Survey  as a substitute for employing the
                  NACE test.

     One comment  argued  that the generator should be allowed

to use  a corrosion  rate  given in the Corrosion Data Survey as

a substitute  for  the  NACE test.  The Agency does not agree.

The Corrosion  Data  Survey gives corrosion rates for water

dilutions of  pure compounds  (24).  Contaminants, however, may

exert a significant  effect on corrosion rate.  Because wastes

are often complex mixtures rather than simple aqueous solutions,

the Agency believes  that  actually performing the NACE test

provides a more appropriate  indication of hazard.

               o   The  corrosiveness of the waste is to be
                  determined  at the point of generation.
                  The  corrosiveness characteristic should not
                  apply  to wastes which lose their corrosive
                  nature  after a certain period of time.

     One comment  asked whether the corrosiveness of the  waste

is to be determined  at  the immediate point at which it becomes

a waste or in  the form  in which the generator disposes of it.

Another comment suggested that the corrosiveness characteristic

should not apply  to wastes which lose their corrosive nature

after a certain period of time.  A waste is defined as

hazardous at  the  point of generation unless it is piped

directly to a  treatment  facility.  Where wastes are stored

before treatment  or  transported in other than a closed pipe

system,  the Agency believes  that the hazardous waste

characteristics must  apply in order to protect human health

and the environment.  The Agency has not exempted from the


                               33

-------
corrosiveness characteristic wastes  which  lose their corrosive

nature  after  a period of time because  (a)  such wastes present

a hazard,  at  least initially (b)  the Agency  has no criteria

for  determining which corrosives  will  persist  and which will

not .

               o  The corrosiveness characteristic should not
                  be applicable to certain  wastes.

      Several  comments stated that the  corrosiveness  characteristic

should  not  be applicable to certain  wastes.   Some comments

stated  that the corrosivenness characteristic  should not

apply to  fly  ash since it is not  containerized and its disposal

does not  involve human contact.   As  discussed  previously,

for  the purpose of hazard definition the corrosiveness charac-

teristic  applies whether a waste  is  containerized or not or

whether waste handlers are involved.   If fly  ash  does not

corrode steel,  and exhibits a pH  less  than 12.5 then it is

not  a hazard  within the meaning of the corrosiveness character-

istic.

     It was suggested that organic acids be  exempted from

application of  the corrosiveness  characteristic because they

tend to degrade under landfill conditions.   Even  if  degra-

dation  does occur the Agency is concerned with storage and

transportation  as well as disposal.   Furthermore,  Appendix D

illustrates that unregulated co-disposal of  organic  acids

and other substances  can result in harmful consequences such

as generation of heat or toxic gases,  fire and explosion.

     Some comments suggested exempting drilling fluid because


                               34

-------
the pH  of  the  material decreases when  it  is  placed  in a reserve

pit.  No data  were given on the pH of  drillng  fluid before

discharge  to  the  pit.   The comment contends  that  this is a

treatment  procedure.   As such, it may  be  acceptable under

Section  3004  standards.   Hazardous was-e  definition standards

under Section  3001,  however, are applicable  at  the  point at

which a  waste  is  generated.  The Agency  sees no reason why

the corrosiveness  characteristic should  not  be  applicable to

drilling fluids  if they  meet the provisions  of  the  characteristic

               o   Separate the pH and metal  corrosion provision
                  in  the  regulations because  they  measure differ-
                  ent  effects.

     One comment  suggested separating  the pH and  metal

corrosion  provisions  in  the regulations  because they measure

different  effects.   The  Agency sees no reason  for doing this.

Each provision covers  a  type of corrosion,  i.e.  corrosion to

living tissue  or  corrosion to metal surfaces and  both types

are properly subsumed  under one characteristic.

               o   Determine the overlap between  the  pH provision
                  and  the metal corrosion  provision  to see
                  whether the metal corrosion provision can
                  be  el iminated.
                    4
     One comment  suggested that the Agency  determine the

overlap between  the  pH provision and the netal  corrosion

provision  to determine whether the metal corrosion  provision

can be eliminated.   The  Agency sees no justification for

this approach.  While  pH is an important  factor in  metal

corrosion,  the two provisions address  different  effects and

are 'not necessarily mutually inclusive.
                               35

-------
      H.    Summary of Data on  the Metal  Corrosion Test Published
           in the NUS Report*  and Response  to Comments Received
           on that Noticed Report

      As  part of the testing program  carried  out under this

contract,  EPA had a sample of  spent  pickle liquor and a sample

of  spent  caustic tested by two  laboratories  to determine the

rate  at  which these wastes corrode SAE  1020  steel.   As

expected,  the coupons exposed  to the spent caustic  showed no

appreciable corrosion.  (Alkaline wastes  are not especially

corrosive  to steel.)  The coupons exposed  to the spent pickle

liquor corroded at rates of 509 inches  per year in  Lab J and

220 inches  per year in Lab K.   The difference in corrosion

rates is  attributed to variations in test  conditions and the

extreme  corrosiveness of the  test medium.   The corrosiveness

characteristic provides that  a  liquid waste  is hazardous if

it has a  corrosion rate greater than 0.25  inch per  year.

      One  comme.nter stated that  the difference between the

corrosion  rate of the spent pickle liquor  samples indicated

that  the NACE test is not reproducible.   The Agency does not

agree.  The reproducibiity of  this test cannot be determined
                                         »
on the basis of the NUS test  performance  since variability

is to be expected at the extremely high corrosion rates

found by the two laboratories.  The  important point is that

the spent  pickle liquor in both samples flunked the corrosivity
*"Evalution  of  Solid Waste Extraction Procedures  and Various
 Hazard Identification Tests (Final Report)",  NUS Corporation,
 September,  1979 .
                               36

-------
characteristic  by  three orders of magnitude and  thus  would

be considered  a hazardous waste.

     VI.   Promulgated Regulation

           The  Agency  has reviewed the comments on  the proposed

regulations  and agrees that the pH limits should be  lowered

from 3.0  to  2.0 and  increased from 12.0 to 12.5.   The

corrosiveness  characteristic is now defined as follows:

§261.22    Characteristic of corrosivity

           (a)   A solid waste exhibits the characteristic  of

corrosivity  if  a representative sample of the waste  has  either

of the following properties:

                (1)   It is aqueous and has a pH less  than  or

equal to  2 or  greater than or equal to 12.5, as  determined  by

a pH meter using either the test method specified  in  the

"Test Methods  for  the Evaluation of Solid Waste, Physical/

Chemical  Methods"*  (also described in "Methods for Analysis

of Water  and Wastes"  EPA 600/4-79-020, March 1979),  or an

equivalent test  method approved by the Administrator  under

the procedures  set  forth in §§260.20 and 260.21.

                (2)   It is a liquid and corrodes  steel (SAE

1020) at  a rate  greater than 6.35 mm (0.250 inch)  per year  at

a test temperature  of 55cC (130CF) as determined by  the  test

method specified in NACE (National Association of  Corrosion

Engineers) Standard TM-01-69** as standarized in "Test Methods
*This document  is  available from Solid Waste Information,
 U.S. Environmental  Protection Agency, 26 W. St. Glair  Street,
 Cincinnati, Ohio  45268.

**The NACE Standard  is  available from the National  Association
  of Corrosion  Engineers,  P.O. Box 986, Katy Texas  7740

                               37

-------
for the Evaluation of Solid Waste, Physical/Chemical Methods,"




or an equivalent  test method approved by  the  Administrator




under the  procedures set forth in  §§260.20  and  260.21.




     (b)   A  solid waste that exhibits the characteristic  of




corrosivity,  but  is not listed as  a hazardous waste  in  Subpart




D, has the EPA  Hazardous Waste Number of  D002.
                               38

-------
                           References


1.   Bates, R.  G.,  Determination of pH, Theory  and  Practice.
     2nd Edition.   John Wiley & Sons, New York,  1973.

2.   Lewis, G.  K.,  Chemical Burns.  American Journal  of Surgery
     95:928-937,  1959.

3.   Encyclopedia  of  Occupational Health and Safety.   Volume  1.
     Geneva, International Labor Office, 1971-72.   pp.  220-221.

4.   MrCreanney, W. C., Skin Care.  In V. Handley,  ed.   Industrial
     Safety Handbook.   Maidenhead, Berkshire, England,  McGraw
     Hill, 1969.   pp.  399-403.

5. •  Birmingham, D. J., Acids,  alkalis, oils and  solvents.   In
     P. Cantor, ed. Traumatic Medicine and Surgery  for the
     Attorney.  Washington, Butterworth, Inc.,  1962.   pp.  364-370.

6.   U.S. EPA.  Office  of Water Programs Operations.   Oil  and
     Special Materials  Control  Division.  Open  Damage  Incident
     Files.

7.   Report to  Congress.   Waste Disposal Practices  and Their
     Effects on Groundwater, U.S. EPA, OWS/OSWMP, January,  1977.

8.   Geraghty and  Miller.  -The  Prevalence of Subsurface Migration
     of Hazardous  Chemical Substances at Selected Industrial
     Waste Land Disposal  Sites.  EPA/530/SW-634.  October,  1977.

9.   Pourbaix,  Marcel.   Atlas of Electrochemical  Equilibria in
     Aqueous Solutions.  Pergamon, Great Britain, 1966.

10.  SCS Engineers, Chemical Speciation of Contaminants in  FGD
     Sludge and Wastewater.  U.S. EPA., SHWRD/MERL,  Contract
     Number 68-03-2371  March, 1978.

11.  Curry, Nolan.  Guidelines  for Landfill of  Toxic  Industrial
     Sludges.   Presented  at the Twency-eighth Industrial Waste
     Conference, Purdue University,  Xav, 1973.
12.   Draft Report.   A Method for Determining Hazardous  Wastes
     Compatibility.  U.S.  EPA Grant Ku-ber R804692.   1979.

13.   Sax, Irving,  Dangerous  Properties of Industrial  Materials
     4th Edition,  Van Nostrand Reinholc.  New York,  1975.

14.   National Academy of  Sciences and National Academy  of
     Engineering..   "Acidity, Alkali-it-, and pH."   Water
     Quality Criteria.  EPA  R3-73-033.  March, 1973.

-------
15.  Butler,  G.  and H. Ison, Corrosion  and  its  Prevention
     in  Waters.   Reinhold, New York.  1966.

16.  49  CFR 173.240  Department  of  Transportation.

17.  21  CFR 191.1  Food and Drug Administration.

18.  16  CFR 1500.3  Consumer Product  Safety  Commission.

19.  A Study  of  Hazardous Wastes in Class  I  Landfills.   EPA
     600/2-78-064.  June, 1978.

20.  Mattack,  A.   pH Measurement and  Titration.   New York,
     MacMillan,  1961.  p. 257.

21.  Standard  Methods for the Examination  of Water  and  Waste-
     water,  14th  Edition (1975).

22.  Blannon,  J.C. and M. L. Peterson.   Survival  of Fecal
     Coliforras  and Fecal Streptococci in  a  Sanitary Landfill.
     Solid  and Hazardous Waste Research.   April  12,' 1974.

23.  Boone  County Field Site Interim  Report  - Test  Cells
     2A, 2B,  2C  and 2D.  EPA 600/2-79-058, July,  1979.   p. 84.

24.  Corrosion Data Survey.   National Association of Corrosion
     Engineers.   1967.

-------
                                                          Appendix  A
              CORROSIVENESS  -  STATE IDENTIFICATION CRITERIA
State
  PH Limits
                 Test  for
               Corrosion of
               Living  Tissue
                                         Test
                                       for  Metal
                                       Corros ion
California  -
Hazardous Waste
Criteria and
Definitions
Illinois - Tenta-
tive Land Dispo-
sal Criteria
Kentucky - Draft
Hazardous Waste
Regulations
Maine - Hazardous
Waste Management
Rules
Michigan - Pro-
posed Hazardous
Waste Regulations
Minnesota - Haz-
ardous Waste
Regulations
Oregon - Draft
Hazardous Waste
Regulat ions
Rhode Island -
Proposed Hazard-
ous Waste Gen-
erator Rules
and Regulations
pH < 2 or > 12
where pH is < 3
or > 10 percent
acidity or alka-
linity must be
determined
pH
3 or
            12
pH < 3 or >_ 12
                 T
pH < 3 or > 12
pH _< 3 or >_ 12
                     Yes
                     16  CFR  1500.41
                           Yes

                     49  CFR 173.240
                     Yes

               16 CFR  1500.41
               49 CFR  173.240
pH < 3 or >_ 12     |
(has provisions    I
for liquids,       I
solids and gases)  I
Yes
                                    Yes
                                    Yes
                                         Yes
                                         Yes
                                    Yes

-------
              CORROSIVENESS  - IDENTIFICATION CRITERIA
State
  PH Limits
Corrosion of
Living Tissue
Metal
Corrosion
Tennessee  -  Pro-
posed Hazardous
Waste Regulations
pH <_ 3 or >_ 12
                    Yes
Texas — Hazardous
Waste Guidelines:
Waste Evaluation
and Classifica-
tion
pH < 2.5 or > 12
                    Yes
Washington - Haz-
ardous Waste
Regulations
pH < 3.0 or > 11.0
(substances which
yield those pH
levels when mixed
with an equal
weight of water)
                    Yes

-------
                           APPENDIX B



   EXAMPLES  IN WHICH  CORROSIVE WASTES CAUSED TISSUE DAMAGE






                       Pennsylvania  1975



     An inspector attempting to halt unauthorized disposal



of a drum  in North Cordorus Township was splashed by the



contents of  the drum  as it ruptured  during compaction. The



inspector  sustained burns on the face and neck.






                        New Jersey 1974



     During  the first ten months of  the year/ seven chemical



waste disposal injuries were noted in the logs of a landfill



Injuries included eye irritation and chemical burns from



exposure to  corrosive wastes.






                          Texas 1971



     Barrels containing chemical wastes were caught in



shrimpers' nets in the Gulf of Mexico.  Physical damage to



nets and equipment occurred,  and exposed shrimper crewmen



experienced  skin burns and eye irritation.

-------
                           APPENDIX C



             CASE HISTORIES OF ACCIDENTS CAUSED BY




               MIXING OF INCOMPATIBLE WASTES  (12)






 1.   Violent. Reaction, Pressure Generation in Tank  Truck



     In Richmond, California, a hazardous waste "hauler mixed, in



     his 30-barrel tank truck,  a liquid waste containing butyl



     acetate in xylene with an etching waste containing



     sulfuric acid,  nitric acid and hydrofluoric acid.



     A hydrolysis reaction took place.  The reaction  generated



     pressure in the tank and blew the safety relief  value



     while  the truck was travelling through a residential



     area.   A private residence was sprayed with the  hazardous



     mixture.   No one was injured,  but considerable clean-up



     and repainting  of the-house was required.



 2.   Formation of Toxic Gas in  Sanitary Landfill



     In Los  Angeles  County,  a tank  truck emptied several



     thousand  gallons of cyanide waste onto refuse  at a sanitary



     landfill.   Another truck subsequently deposited  several



     thousand  gallons of acid waste at the same  location.



     Reaction  between the acid  and  the cyanide evolved large



     amounts of toxic hydrogen  cyanide gas.   A potential



     disaster  was averted when  a local chlorine  dealer was



     quickly called  to oxidize  the  cyanide with  chlorine




     solution.



3.   Formation of Toxic Gas  in  Excavated Site



    A load of acidic aluminum  sulfate waste was. inadvertently

-------
    discharged into an excavation already containing some sulfide



    waste.  Hydrogen sulfide was released, and the lorry driver



    died in his cab at the landfill site.



4.  Formation of Toxic Gas and Explosion in Waste Tank



    Sulfide waste was added to a soluble oil waste in a tanker



    and subsequently added to other oily wastes in a tank.



    Later treatment of the oil with acid to break the emulsified



    oil resulted in evolution of hydrogen sulfide.  Two



    operators were briefly affected by the gas.  There



    was also an explosion in the tank.



5.  Formation of Toxic Gas at a Landfill



    At a sanitary landfill near Dundalk, Maryland, a 2,000



    gallon liquid industrial waste load containing iron



    sulfide,  sodium sulfide, sodium carbonate and sodium



    thiosulfate along with smaller quantities of organic



    compounds was discharged into a depression atop an earth-



    covered area of the fill.  When it reached eight to ten



    feet below the point of discharge, the liquid started



    to bubble and fume blue smoke.   The smoke cloud quickly



    engulfed  the truck driver and disabled him.   Several



    nearby workers rushed to his aid and were also felled.



    During the clean-up operation,  one of the county fire— •




    fighters  also collapsed.  All six of the injured were



    hospitalized and treated for hydrogen sulfide poisoning.



    It was not determined whether the generation of hydrogen

-------
 sulfide was due to the instability of the waste  or  the

 incompatibility of the waste with some of the landfill

 materials.  The pH of the waste was measured to  be  13

 before it left the plant.

 Formation of Toxic Gas in a Disposal Well
                      *
 At a land disposal site in Southern California,  a tanker

 was observed unloading a waste  listed as  "waste  acid

 (5% HC1)" into a bottomless tank through  an open stack

 above the ground.  Shortly after the unloading operation

 commenced,  yellowish-brown clouds of nitrogen dioxide

 began to emanate from the open  stack.   The reactions

 appeared to have subsided when  the discharging of the

 wastes ceased.   However,  an hour later more NC>2  started

 to spew from the stack.   The  emission was  halted by

 filling the stack with soil.  There were  no injuries,

but the incident created  a significant air pollution

problem.   Complaints  from nearby business  were received

and a factory was evacuated.

Fire,  Dispersal  of Toxic  Dusts  from Leaky  Containers

At  a dump in Contra Costa County,  California, a  large

number of drums  containing solvents  were deposited in a

landfill.   In the immediate area were  leaky containers•

of  concentrated  mineral acids and several  bags containing

beryllium wastes in dust  form.   The  operators failed

to  cover  the  waste at  the  end of the day.   The acids

reacted with  the solvents  during the night,  ignited

-------
    them and started a large chemical fire.  There was possible



    dispersion of beryllium dust into the environment.



    Inhalation, ingestion or contact with beryllium dust by



    personnel could have led to serious health consequences.



8.  Violent Eruption in Waste Drum



    At an engineering works, hot chromic.acid waste was in-



    advertently added to a drum containing methylene chloride



    waste from degreasing operations.  There was a violent



    eruption resulting in chemicals being sprayed locally



    in the workshop but no one was harmed.



9.  Nitrogen Oxide Generation at a Sanitary Landfill



    A truck driver picked up a load of "nitric acid" from an



    automotive specialities manufacturing company in early



    July 1976 and delivered it to a site in Southern California



    for well disposal.   The well accepted approximately 50



    gallons and then "pressurized".   The driver then took



    the remainder of the load to another landfill in Southern



    California for trench disposal.   Upon unloading,  a reaction



    took place which generated brown nitrogen dioxide fumes



    which were carried by the wind and interfered with traffic



    500 yards away.   Towards the end of the month the same



    driver picked up another load of the same type from the



    same company and delivered it directly to the second



    landfill site.   Upon arrival at the weigh station,  he



    was instructed to tell the catapillar driver to "dig a



    deep hole".   The catapillar operator dug a hole approxi-

-------
     raately 12 ft.  deep,  12  ft.  wide, and 20 ft. long into a



     previously filled area.   The truck driver said that he



     observed  damp  ground and  decomposing refuse in the



     trench.   The driver  then  unloaded his truck and backed



     away from the  trench as he did not want to be exposed to



     the hazard he  had observed on the previous occasion.  He



     observed  a dense  brown cloud emanating from the trench



     and could not  return to his truck until its contents had



     been drained and  the hazard reduced.  A chemical analysis




     of the retained sample showed that it contained approximately



     70% nitric acid and  5% hydrofluoric acid along with



     aluminum  and chromium.  The sample was funing when it




     was taken  from the truck.



10.  Cyanide Generation at A Sanitary Landfill




     A standard procedure at a Southern California disposal



     site for handling liquid wastes containing cyanides



     and spent caustic solutions was to inject these loads



     into covered wells dug into a completed section of a



     sanitary landfill.   Routine air sampling in the vicinity



     of the wells detected low levels of HCN.  Sampling in the



     well head detected more than 1000 ppm HCN.   No cyanide



     was detected during addition of the spent caustic to  -  .



     a  new well.  On the basis of these discoveries,  use of



     the wells was discontinued.   The cyanide gas was ap-



     arently formed in the well as a result of lowering of



     the pH of the waste by CC>2 and organic acids produced

-------
     in the decomposition of refuse.



11.  Nitric Acid and Alcohol Cause Explosion of Tank Car;



     While transfering 64% nitric acid to a supposedly empty



     tank car, the tank car exploded.  An investigation



     revealed that the tank car contained a small residual



     of alcohol which was converted to acetaldehyde by the



     acid.  The heat of reaction vaporized the acetaldehyde



     and subsequently ignited the acetal<*ehyde-air mixture



     causing an explosion.  No injuries or fatalities resulted.



12.  Nitric Acid - Ammonia Fire Generate Toxic Fumes



     In a Carroll County, Arkansas fertilizer warehouse, a



     mixture of ammonia and nitric acid ignited and destroyed the



     plant.  Toxic fumes generated by the blaze forced the



     evacuation of the town's residents.   No injuries or fat-



     alities were reported.



13.  Vacuum Truck Rupture Caused by Formation of Hydrogen Gas



     In Los Angeles,  a vacuum truck containing an unknown



     quantity of residual wastes picked-up a spent sulfuric



     acid metal stripping solution.   On the way to the disposal



     site a violent explosion ocurred, rupturing the tank and



     injuring the driver.   Subsequent investigation revealed



     that the residue in the tank prior to the pick-up of the



     acid solution contained aluminum and magnesium turnings and



     fines.   The action of the  acid on these metal particles



     produced hydrogen gas and  heat.   Extreme pressure build-



     up resulted in the violent rupture of the tank.

-------
                           APPENDIX D



              REACTIONS BETWEEN ACIDS OR BASES AND



      OTHER SUBSTANCES-POSSIBLE ADVERSE CONSEQUENCES  (12)






 MINERAL ACIDS + ALCOHOLS AND GLYCOLS



 Dehydration reactions and displacement with  the halide



 result in heat generation.



 MINERAL ACIDS -I- ALDEHYDES



 Condensation reactions cause heat generation.  Acrolein



 and other unsaturated aldehydes polymerize readily.



 MINERAL ACIDS + AMIDE



 Hydrolysis of amide to the corresponding carboxylic



 acid results in an exotherm.



 MINERAL ACIDS + AMINES



 The  acid base reaction between these two types of



 compounds forming  the ammonium salts may be  sufficiently



 exothermic to cause a hazard.



 MINERAL ACIDS + AZO COMPOUNDS



 Amyl azo and diazo compounds decompose  exothermically



 upon mixing  with strong mineral acids to yield nitrogen



 gas and  the  corresponding  amyl cation.  Aliphatic azo and



diazo compounds/ particularly  diazoalkanes,  can polymerize



violently with heat generation.   Organo azides can also



decompose  exothermically with  strong acid to form nitrogen




gas and  the  respective cations.   An  exotherm also results



from the  acid-base reaction of hydrazines with mineral acids

-------
 as  hydrazines are comparable in base strength to  ammonia.




 Diazomethane is a particularly reactive  compound  in  this group.




 MINERAL  ACIDS + CARBAMATES




 Carbamates  can undergo hydrolysis as well  as  decarboxylation




 upon  mixing with strong mineral acids.   Both  reactions  are




 exothermic  and the latter can generate pressure if  it  occurs




 in  a  closed container.




 MINERAL  ACIDS + CAUSTICS




 The acid-base reaction between strong mineral acids  and




 strong caustics is extremely exothermic  and can be  violent.




 Fires can result if the caustic substance  is  an alkoxide.




 MINERAL  ACIDS + CYANIDE




 Inorganic cyanides rapidly form extrerrel.y  toxic and  flam-




 mable hydrogen cyanide gas upon contact  with  mineral acids.




 MINERAL  ACIDS + DITHIOCARBAMATES




 Acid  hydrolysis of dithiocarbamate heavy metal salts with




 strong mineral acids yields extremely flammable and  toxic




 carbon disulfide gas.   An exotherm can be  expected  from the




 reaction.




MINERAL  ACIDS + ESTERS




 Strong mineral acids in excess will cause  hydrolysis and .




 decomposition of esters with heat generation.




MINERAL  ACIDS + ETHERS




Ether may undergo hydrolysis with strong acids exothermi-




cally.

-------
 MINERAL ACIDS + FLUORIDES

 Most inorganic fluorides yield toxic and corrosive hydrogen

 fluoride gas upon reaction with strong mineral acids.

 MINERAL ACIDS + HALOGENATED ORGANICS

 Strong mineral acids in excess may cause decomposition with


 generation of heat and toxic fumes of hydrogen halides.

 MINERAL ACIDS + ISOCYANATES

 Acid catalyzed decarboxylation as well as vigorous decompo-

 sition can occur upon mixing of isocyanates  with  strong

 mineral acids.

 MINERAL ACID + KETONE
                                        *
 Acid catalyzed aldol condensation occurs exothermically.

 MINERAL ACIDS 4- MERCAPTANS

 Alkyl mercaptans are particularly reactive with mineral acids


 yielding extremely toxic and flammable hydrogen sulfide gas.

 Other mercaptans can yield hydrogen sulfide  with  excess strong

 acids.   Excess  strong acid can also result in  decomposition


 and  generation  of toxic fumes of sulfur oxides.

 MINERAL ACIDS + ALKALI AND ALKALINE EARTH METALS

 The  reaction of strong mineral acids wifb alkali  and alkaline


 earth metals in any form will result in a vigorous exothermic

 generation of flammable hydrogen gas and possible fire.

 MINERAL ACIDS 4- METAL POWDERS,  VAPORS,  OR SPONGES


 Reactions  of strong mineral acids with finely  divided

metals  or  metals in a form with high surface area will result

-------
 in vigorous generation of flammable hydrogen gas and possible




 explosion caused by the heat of reaction.




 MINERAL  ACIDS + METAL SHEETS, RODS, DROPS. ETC.




 Strong mineral acids will form flammable hydrogen gas upon




 contact  with metals in the form of plates, sheets, chunks,




 and other bulk forms.   The heat of reaction may ignite  the




 gas formed.




 MINERAL  ACIDS + NITRIDES




 The aqueous  fraction of strong mineral acids will- react with




 nitrides  evolving caustic and flammable ammonia gas.  The




 acid-base reaction of  mineral acids and nitrides can also




 evolve much  heat and ammonia.




 MINERAL  ACIDS -1- NITRILES




 Exothermic hydrolysis  of nit-riles to the corresponding




 carboxylic acid and ammonium ion is known to occur with




 mineral  acids.   Extremely toxic and flammable hydrogen




 cyanide  gas  may be evolved with such compounds as acetone,




 cyanohydrin  and propionitriles.




 MINERAL ACIDS  + UNSATURATED ALIPHATICS




 Addition  of  mineral acids to alkenes usually results in




 exothermic acid catalyzed hydration and partial addition of




 the hydrogen halide or  sulfates.   Acetylenes are also sus-




 ceptible  to  exothermic  acid catalyzed hydration, forming the




 corresponding  aldehyde  or ketone with possible addition of




 the hydrogen halide in  the case  of halogen acids.




MINERAL ACIDS  + ORGANIC PEROXIDES




Strong mineral  acids can react with organic peroxides and

-------
 hydroperoxides with enough heat generated  to  cause  explosive




 decomposition in the more unstable compounds.   Oxygen  can




 also  be  generated.




 MINERAL  ACIDS + PHENOLS AND CRESOLS




 Exothermic sulfonation reactions can occur with addition of




 sulfonic acid to phenols and cresols.  Substitution of the




 hydroxyl with a halide can occur with addition  of the  halogen




 acids.   Excess strong acid can decompose phenols and cresols




 with  heat generation.




 MINERAL  ACID  + ORGANOPHOSPHATES




 Excess strong mineral acid can cause decomposition  of  organo-




 phosphates, phosphothioate and phosphodithioates with  heat




 generation and possible toxic gas formation.




 MINERAL  ACIDS + SULFIDES




 Extremely toxic and flammable hydrogen sulfide  gas  results




 from  the combination of mineral acids and  sulfides.




 MINERAL  ACIDS + EPOXIDES




 Acid  catalyzed cleavage can occur, initiating polymerization




 with  much heat generated.




 MINERAL  ACIDS + COMBUSTIBLE MATERIALS




 Dehydration and decomposition on addition  of  excess  strong




 mineral  acid  can cause heat and possible toxic  gas  generation,




'MINERAL  ACIDS -I- EXPLOSIVES




 Many  explosives are extremely heat sensitive  and can be




 detonated by  heat generated from the action of  strong




 mineral  acids on these compounds.

-------
  MINERAL ACIDS + POLYMERIZABLE COMPOUNDS
  Strong mineral acids can act as initiators  in  the  poly-




  merization of these compounds.  The reactions  are  exothermic




  and can occur violently.




  MINERAL ACIDS + STRONG OXIDIZING AGENTS




  Many combinations of strong mineral acids and  strong  oxidizing




  agents are sensitive to heat and shock and  may decompose




  violently.   The halogen acids may be oxidized  yielding




  highly toxic and corrosive halogen gases, accompanied by




  heat generation.




 'MINERAL ACIDS + STRONG REDUCING AGENTS




  Many reducing agents form flammable hydrogen gas on contact




  with mineral acids.   The heat generated can cause  spontaneous




  ignition.   Some reducing agents such as metal phosphides  and




  inorganic  sulfides evolve extremely toxic and  flammable




  fumes  of phosphine and hydrogen sulfides, respectively.




  MINERAL  ACIDS + WASTE  AND MISCELLANEOUS AQUEOUS MIXTURES




  Much heat  can be evolved upon solubilization and hydrolysis




  of  these acids.




  OXIDIZING  MINERAL  ACIDS 4- ORGANIC ACIDS




 These  mineral acids  can oxidize the hydrocarbon moeity  of




  organic  acids with resulting heat and gas formation.




' OXIDIZING  MINERAL  ACIDS + ALCOHOLS AND GLYCOLS




 Oxidation  of  the  hydrocarbon moeity can occur resulting in




 heat and gas  formation.   Nitration with nitric acid can take




 place  in the  presence  of sulfuric acid forming extremely




 unstable nitro  compounds.

-------
 OXIDIZING MINERAL ACIDS + ALDEHYDES



 Oxidation of the hydrocarbon raoeity can occur resulting in




 heat and gas formation.



 OXIDIZING MINERAL ACIDS + AMIDES



 Oxidation with excess acid can result in heat generation and



 formation of toxic fumes of nitrogen oxides.



 OXIDIZING MINERAL ACIDS + AMINES



 The  acid-base reaction produces much heat  and exhaustive



 oxidation results in generation of  heat and toxic fumes of



 nitrogen oxide.



 OXIDIZING MINERAL ACIDS + AZO COMPOUNDS



 Azo  compounds and diazo compounds are easily  decomposed by



 strong  acids evolving much heat and nitrogen  gas. . They are



 very susceptible to oxidation and can evolve  toxic fumes



 of nitrogen  oxides upon exhaustive  oxidation.  Hydrazines are



 expecially susceptible to oxidation and inflame upon contact



 with oxidizing agents.  Many of the compounds  in this group



 such as diazomethane and the azides are very  unstable and



 can  decompose explosively upon heating.



 OXIDIZING MINERAL ACIDS + CARBAMATES



 Carbamates can undergo exothermic hydrolysis  and decarboxyla-



 tion upon mixing with these acids.   Exhaustive oxidation can



 also result  in formation of toxic fumes  of nitrogen oxides,



 and  sulfur oxides in the case of thiocarbamates.



 OXIDIZING MINERAL ACIDS + CAUSTICS



 The  neutralization reaction can be  violent with evolution of




much heat.

-------
 OXIDIZING MINERAL ACIDS + CYANIDES




 Evolution of extremely toxic and flanmable hydrogen  cyanide




 gas  will occur before oxidation.




 OXIDIZING MINERAL ACIDS + DITHIOCARBAMATES




 Acids  will cause decomposition of dithiocarbamates with




 evolution of extremely flammable carbon disulfide.   Significant




 heat may be generated by the oxidation and decomposition  to




 ignite the carbon disulfide.




 OXIDIZING MINERAL ACIDS + ESTERS




 Exhaustive oxidation of esters can cause decomposition with




 heat and possible ignition of the more flammable esters.




 Conversion to  the organic acid and decarboxylation can also




 occur.




 OXIDIZING MINERAL ACIDS..+ ETHERS




 Heat generated from the exhaustive oxidation of ethers can




 ignite the more flammable ethers.  These compounds can also




 undergo  exothermic acid catalyzed cleavage.




 OXIDIZING MINERAL ACIDS + FLUORIDES




 Gaseous  hydrogen  fluoride can result from a combination of




 inorganic fluorides and these acids.  Hydrogen fluoride is




 extremely corrosive and toxic.   Some heat can also be evolved.




 OXIDIZING MINERAL + HALOGENATED ORGAKICS




These  acids  can cause  oxidation and decomposition of




halogenated  organics resulting in heat and generation of




extremely  toxic  fumes  of  hydrogen chloride, phosgene, and




other  gaseous  halogenated compounds.

-------
 OXIDIZING MINERAL ACIDS  + ISOCYANATES
 Isocyanates may be  hydrolyzed by the water in concentrated




 acids to yield heat and  carbon dioxide.   They may also be




 oxidized by these acids  to  yield heat and toxic nitrogen




 oxides.




 OXIDIZING MINERAL ACIDS  + KETONES




 Ketones  can undergo  exothermic aldol condensations under




 acidic conditions.   Oxidizing acids can  cleave the ketone to




 give  a mixture of acids.  Excess acid can cause complete




 decomposition yielding much heat and gas.   Fire can also




 r esult.




 OXIDIZING MINERAL ACIDS  + MERCAPTANS




 Extremely toxic and  flammable hydrogen sulfide gas can be




 formed by the action of  the acid on mercaptans.   Oxidation




 of mercaptans and other  sulfur  compounds  can result in formation




 of toxic sulfur dioxide  and heat.




 OXIDIZING MINERAL ACIDS  + ALKALI AND ALKALINE EARTH METALS




 Extremely flammable hydrogen gas can be  generated upon contact




 of acids and  these metals.    The  reaction  of  such a strong




 oxidizing agent and strong  reducing agents can be so violent




 as to  cause a fire and possibly  an  explosion.




 OXIDIZING MINERAL ACIDS  + METAL  POWDERS,  VAPORS,  AND SPONGES




 The action  of acid on these  metals  produces  hydrogen gas




 and heat.   Due to the large  surface area  of  these forms of




metals,  the reaction can occur with explosive violence.




 OXIDIZING MINERAL ACIDS  + METAL  SHEETS, RODS,  DROPS. ETC.




The reaction  of acids on metals  as  sheets,  plates, and other

-------
 bulk forms can evolve hydrogen gas  and  some heat*   Although




 the reaction proceeds much slower than  in  the case  of  powders,




 a definite fire hazard exists.  Many metals are  attacked




 by nitric acid.




 OXIDIZING MINERAL ACIDS + NITRIDES




 Nitrides are extremely strong bases and  will participate in




 an acid-base reaction evolving much heat.   This  reaction can pro-




 ceed with explosive violence due to the  instability of metal




 nitrides and the generation of flammable ammonia gas.




 OXIDIZING MINERAL ACIDS + NITRILES




 The primary hazard in mixing these  types of compounds  appears




 to be oxidation of the nitriles with generation  of  heat




 and toxic fumes of nitrogen oxides.  In  some cases  such as




 acetone  cyanohydrin and propionitrile,  extremely toxic hydrogen




 cyanide  gas is  known to result from ciising  with  strong acids.




 These fumes are also flammable.   Mixtures  of nitric acid and




 acetonitrile are high explosives.




 OXIDIZING MINERAL ACIDS + NITRO COMPOUNDS




 These acids can decompose nitro compounds  to produce heat




 and  toxic fumes of nitrogen oxide.   This oxidation  can be




 extremely violent.   Mixtures.of nitric acid and  nitro-




 aromatics are known to exhibit explosive properties.




Mixtures  of some nitroalkanes  (nitronethane)  with nitric




acid  can  also be detonated.




OXIDIZING  MINERAL ACIDS  + UNSATURATED ALIPHATICS




Aliphatic  unsaturated hydrocarbons are extremely susceptible




to oxidation resulting in heat generation and  fire.

-------
 OXIDIZING MINERAL ACIDS  + SATURATED ALIPEATICS


 Aliphatic saturated  hydrocarbons  are easily oxidized by


 these acids yielding heat and carbon dioxide.


 OXIDIZING MINERAL ACIDS  + ORGANIC PEROXIDES


 The lower molecular  weight organic peroxides and hydro-


 peroxides are very sensitive  to heat and shock.   Mixing
                                             •j - \    : • i

 of  oxidizing mineral acids with such unstable  compounds
  »•                            . .                   '

 can cause heat generation due to  the oxidizing capacity of


 the acids and acid catalyzed  hydrolysis.  These  reactions


 can cause explosive  decomposition.


 OXIDIZING MINERAL ACIDS  + PHENOLS  AND CRESOLS


 Phenols  and cresols  are  easily oxidized and excess oxidizing


 acids can result in  much heat generation.


 OXIDIZING MINERAL ACIDS - + ORGANOPHOSPHATES


 Excess  oxidizing acid can decompose these  compounds  to yield


 heat  and toxic fumes of  nitrogen  oxides, sulfur  oxides, and


 phosphorous oxides.


 OXIDIZING MINERAL ACIDS  + WATER AND WATER  MIXTURES


 Much  heat can be evolved  from the  dissolution  of these


 acids by water.


 OXIDIZING MINERAL ACIDS  + SULFIDES


 Toxic and flammable  hydrogen  sulfide gas can be  generated by


 the action of these  acids  on  inorganic  sulfides.   These


 sulfides can also be oxidized  exothemically to  sulfur dioxide,


 also  a  toxic gas.  This  reaction  can occur  very  violently.


OXIDIZING MINERAL ACIDS + EPOXIDES


Epoxides are very easily  cleaved  by acids  with heat  generation.

-------
 This ring opening can be the initiating step in the  formation




 of epoxy resins,  and uncontrolled polymerization can result  in



 extreme lieat generation.  The oxidation capacity of  these



 acids can cause ignition of the epoxides.



 OXIDIZING MINERAL ACIDS + COMBUSTIBLE MATERIALS



 Oxidizing mineral acids can decompose some substances with heat



 generation and possible fire.   Toxic gases may also  be  formed



 as combustion products,  but the type of gas will depend upon



 the composition of these miscellaneous substances.



 OXIDIZING MINERAL ACIDS + EXPLOSIVES



 Such strong acids can easily detonate compounds in this group



 of explosives due to the heat  generated upon mixing.  The



 oxidizing character of these acids merely  enhances the



 possibility of detonation.



 OXIDIZING MINERAL ACIDS  + POLYMERIZABLE COMPOUNDS



 These acids can act as initiators  in the polymerization of



 many compounds.   These reactions are exothermic and  can



 occur violently.   In addition,  these acids can oxidize



 certain  compounds producing  more heat and  possible toxic




 fumes.



 OXIDIZING MINERAL ACIDS  + STRONG REDUCING  AGENTS



 Mixing of compounds  in these two groups can result in very




 violent,  extremely exothermic  reactions.   Fires  and  explosions



 can  result.



 ORGANIC ACIDS  + ALDEHYDES



Exothermic  condensation  reactions  can occur between  these



two types of compounds.   The acidic  character  of the organic

-------
 acids may be sufficient to catalyze the reaction.  Polybasic and



 unsaturated acids are susceptible to polymerization under these




 condition, resulting in much heat generated.



 ORGANIC ACIDS + AMINES



 An acid-base reaction between the stronger acids and amines




 can generate some heat.   Dicarboxylic acids and diamines



 can copolymerize with heat generation.



 ORGANIC ACIDS + AZO COMPOUNDS



 Aliphatic and aromatic diazo compounds are readily decomposed



 by organic acids releasing heat and nitrogen gas as reaction



 products.  Azo compounds are not sensitive to  such decomposition.



 Hydrazine azide is extremely sensitive to heat or shock.  An



 acid-base reaction with  hydrazine can produce  some heat.



 ORGANIC ACIDS + CAUSTICS




 Acid-base reactions produce heat.



 ORGANIC ACIDS + CYANIDES



 Hydrogen cyanide,  an extremely toxic and flammable gas, is




 generated upon mixing.



 ORGANIC ACIDS + DITHIOCARBAMATES



 Toxic  and flammable carbon disulfide can be formed upon




 contact of dithiocarbamate with the stronger organic acids.



 Although CS2 is a  liquid at room temperature,  it has a very



high vapor pressure.   Some heat can be generated from the




hydrolysis of the  dithiocarbamate salts.



 ORGANIC ACIDS + FLUORIDES



Toxic  and corrosive hydrogen fluoride fumes can be generated



by the action of strong  organic acids upon metal fluoride

-------
  salts.  Alkali metal fluorides are  especially susceptible




  to decomposition in this manner.




  ORGANIC ACIDS + ISOCYANATES




  Some water is normally associated with  organic acids,  and




  this can cause hydrolysis of isocyanates  to  carbon  dioxide




  and amines with some heat generated.




  ORGANIC ACIDS + ALKALI AND ALKALINE EARTH METALS




  Reaction of organic acids with these metals  in any  form




  can result in exothermic generation of  flammable  hydrogen




  gas and possible fire.




  ORGANIC ACIDS + METAL POWDERS, VAPORS,  AND SPONGES




  The stronger  organic acids can liberate flammable hydrogen




  gas upon contact with metals in these forms.   The heat  of




  reaction can  cause  explosions.




  ORGANIC ACIDS + NITRIDES




  An  acid-base  reaction can occur resulting  in  heat and  possible




  evolution  of  flammable ammonia gas.  Many  of  these nitrides




  are explosively unstable and can be detonated  by  the heat of




  reaction.




  ORGANIC ACIDS + NITRILES




  Strong  organic acids can convert nitriles  to  their  corres-




  ponding organic acid with some  heat generation.




'  ORGANIC ACIDS + SULFIDES




 Extremely  toxic and flammable hydrogen  sulfide and  some heat




 can be  generated.




 ORGANIC ACIDS + EPOXIDES




 Acid catalyzed cleavage  of the  epoxide ring can initiate

-------
 violent polymerization with much heat generated.



 ORGANIC ACIDS + EXPLOSIVES



 Strong organic acids can decompose compounds  in this group



 resulting in enough heat to cause detonation.



 ORGANIC ACIDS + POLYMERIZABLE COMPOUNDS



 Strong organic acids can initiate cationic polymerization.




 Dicarboxylic acids can copolymerize with  diamines as in the



 reaction of adipic acid and hexamethylene diamine to form



 Nylon 6,6.



 ORGANIC ACIDS + OXIDIZING AGENTS



 The hydrocarbon moeity of the organic acids are susceptible



 to decomposition by strong oxidizing agents releasing heat and




 gas.   The gas produced can be toxic if the acid contains



 halogens such as dichlorophenoxy acetic acid, or if it contains



 other hetero atoms.



 ORGANIC ACIDS + REDUCING AGENTS



 Carboxylic  acids are easily reduced by lithium aluminum



hydride to  the corresponding alcohols with some heat genera-




 tion.   Other reducing agents require more vigorous reaction



 conditions.   Flammable hydrogen  gas can be produced from the



 extractions  of the hydroxyl proton and the ^ -hydrogens.




 CAUSTICS -I-  ESTERS



Esters  are  easily hydrolyzed by  caustics  to a salt and



alcohol  with heat generation.




CAUSTICS +  HALOGENATED ORGANICS'



Aliphatic halides can undergo substitution or dehydro-



halogenation upon treatment with  strong caustics.  Both

-------
 processes involve some heat generation while the second



 evolves flammable olefins and acetylenes, especially with



 the lower molecular weight compounds.  Halogenated aromatics,



 however,  are relatively stable to strong caustics.



 CAUSTICS  + ISOCYANATES



 Caustics  catalyze the polymerization of diisocyanates



 yielding  much heat.   The mono isocyanates decompose to



 amines and carbon dioxide upon contact with caustics.



 CAUSTICS  + KETONES



 Caustics  can catalyze the self-condensation of ketones,



 yielding  heat.



 CAUSTICS  + ALKALI AND ALKALINE EARTH MET.M.S



 Heat  and  flammable hydrogen gas can be generated due to  the



 aqueous nature  of most caustics.



 CAUSTICS  4- METAL POWDERS,  VAPORS,  AND SPONGES



 Heat  and  flammable hydrogen gas may be generated with some



 metals such as  aluminum,  magnesium,  zinc, and beryllium.



 Explosions  may  also  occur due  to  the high surface area of



 these  forms.



 CAUSTICS  +  NITRO COMPOUNDS



 Nitro  alkanes and caustics form salts in the  presence of



 water.  The dry salts  are explosive.



 CAUSTICS  +  ORGANOPHOSPHATES



 Alkaline hydrolysis  of phosphorothioates can  generate



 enough heat  to  cause explosive  rearrangement  from the



 thiono to the thiolo form.   Hydrolysis  of other organo-




phosphates can  generate heat.

-------
CAUSTICS -I-  EPOXIDES
Base catalyzed cleavage can result  in polymerization  with




much heat.




CAUSTICS +  EXPLOSIVES




Alkaline hydrolysis or other reactions can generate




enough heat to detonate these compounds.




CAUSTICS +  POLYMERIZABLE COMPOUNDS




These compounds can undergo anionic polymerization with




caustics as initiators yielding much heat.

-------