I.   Introduc t ion

     Subtitle  C  of  the  Solid  Waste Disposal Act, as amended

by the Resource  Conservation  and Recovery Act of 1976 creates

a comprehensive  "cradle-to-grave" management control systea

for the disposal of  hazardous waste designed to protect the

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 3002-3005

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 reactivity

is a hazardous characteristic because improperly managed

reactive wastes  (i.e., explosives, etc.) 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  reactive wastes, to discuss the comments received

on the proposed  definition of reactive waste (43 FR 58956,

December 18,  1978) and  the changes subsequently made.

I1.  Proposed  Regulation

     Reactive  waste.   (1) Definition - A solid waste is a

hazardous waste  if a representative sample of the waste:

     (i)  Is normally unstable and readily undergoes violent

chemical change without  detonating;  reacts violently with

water,  forms potentially  explosive mixtures with water, or

generates toxic  gases, vapors, or fumes when mixed with water;

or is a cyanide or  sulfide bearing waste which can generate

toxic gases, vapors, or fumes when exposed to mild acidic or

basic conditions.

     (ii) Is capable of detonation or explosive reaction but

requires a strong initiating source or which must be heated

under confinement before initiation can take place, or which

reacts explosively  with water.

     (iii) Is readily capable of detonation or of explosive

decomposition or reaction at normal temperatures and pressures

     (iv) Is a forbidden explosive as defined in 49 CFR

173.51, a Class A explosive as defined in 49 CFR 173.53, or a

Class B explosive as defined in 49 CFR 173.58.

     NOTESuch waste includes pyrophoric .substances,

     explosives, autopolymerization material and oxidizing

     agents.   If it is not apparent whether a waste is a

     hazardous waste using this description,  then the

     methods cited below or equivalent methods can be used

     to determine if the waste is hazardous waste.

     Identification method.  (1)  Thermally unstable waste

can be  identified using the Explosion Temperature Test cited

in Appendix II of this Subpart (waste for which explosion,

ignition,  or decomposition occurs at 125C after 5 ninutes is

classed as hazardous waste).

     (i)   Waste unstable to mechanical shock can be identified

using the Bureau of Explosives impact apparatus and the tests

cited in  49 CFR 173.53 (b), (c), (d),  or (f),  as appropriate.


Ill. Rationale for Proposed Regulation

     A.   Rationale for proposing a reactivity characteristic

     Reactivity was chosen as a characteristic of hazardous

waste because improperly managed reactive wastes present a

danger to human health and the environment.  By definition,

reactive wastes are those which are capable of violently

generating heat and pressure, reacting vigorously with air or

water, reacting with water to generate toxic fumes, etc.  The

dangers which these wastes pose to transporters, waste disposal

personnel, and the public are thus for the most part obvious.

In the past, there have been a number of incidents of damage

to persons or property which have resulted from the improper

management of reactive wastes.  Some of these damage incidents

are listed and discussed in Appendix I.

     Because of their acknowledged danger, reactive materials

are often controlled by federal and state regulations and

suggestions for their safe use or management are often

published by public or private organizations.  Some of these

federal and state regulations and the guidelines for reactive

materials prescribed by the National Fire Protection Association

(NFPA) are listed and discussed in Appendix II.

     B.   Rationale for proposed reactivity definition

     Reactive substances can be described as those which:

     1)   autopolymerize

     2)   are unstable with respect to heat or shock

     3)   are explosive


      4)    are strong oxidizers

      5)    react vigorously with air or water

      6)    react with water to generate toxic  fumes

      As  can  be seen from this description, the  tern  "reactivity"

 encompasses  a diverse and somewhat loosely conjoined  class  of

 physical  properties or effects.   These effects  are not  mutually

 exclusive  and a particular substance might exhibit several  of

 the properties mentioned above.   For instance,  certain

 peroxides  would fall into four of the above six  categories.

 Additionally,  these categories overlap not only  with  each

 other, but also with the other characteristics.  For  example,

 the difference between flammabi1ity (conflagration)  and  ex-

 plosiveness  (deflagration)  is only one of degree --  an  illustra-

 tion  of the  fact  that the properties embraced by the  term

 "reactivity"  are,  like the term  "reactivity" itself,  relative

 properties which  have meaning only in a relative sense.

      The Agency has attempted where possible to  define

hazardous waste characteristics  in terms  of specific,

numerically  quantified properties measurable by  standardized

 and available  testing protocols.   This has proven difficult

in the case  of  reactive  wastes.   The first problen vith

constructing  a  numerically  quantified  definition cf  reactive

wastes arises  from  the fact  that  the term "reactivity" ecbraces

a wide variety  of different  (though overlapping) effects,

each  of which  can be  triggered by an equally wide variety of

initiating conditions  or  forces.   It would be cumbersome, if

not completely  impractical,  to construct  a numerically


quantified definition which  included all these different

effects  and their potential  initiating  forces.  The second

problem  arises  from the  fact, as noted  above, that the

properties embraced by the term reactivity are relative

properties.  The determination that something "reacts vigorously

with air or water" or is  "unstable with respect to heat or

shock" is a relative determination, not an absolute one.  The

effects  being measured proceed along a  continuum.  Thus, it

is difficult to draw the  line at any particular point.

     These problems are  reflected in the testing methods

which might be used to identify reactive substances.  These

methods  suffer  from the  following generic deficiences:

     1.   The available tests are too specific and do not
          reflect the wide variety of waste management

     The available tests  are used to determine how a specific

aspect or manifestation of waste reactivity behaves under a

special  and specific type of stress.  For example, DTA

(Differential Thermal Analysis) measures how the rate of

temperature rise of the waste (one specific aspect of waste

reactivity) correlates with the slow input of thermal energy

(one special and specific type of stress).  This would not

indicate how the waste reacts to mechanical shock (a drop

test would be necessary to determine that), electrical shock,

whether  the waste is a strong oxidizer, or even what is

producing the rate of temperature change (pressure buildup,

toxic or nontoxic fumes,  heat of mixing, etc.).   The information

derived  from the available tests,  then, is too specialized

and does not reflect the wide variety of stresses and initiating

forces likely to be found in a disposal environment.

     2.   Reactivity of a sample may not reflect reactivity of
          the whole waste:

     In the case of wastes which are thermally unstable, the

reactivity of the sample may not adequately reflect the

reactivity of the whole waste.  The kinetics of reaction are

not only a function of the available initiating sources and

ambient temperature, but are also a function of the mass,

configuration,  geometry, etc. of the sample.  For a "runaway"

reaction to occur, the system must transcend that steady

state where the energy (heat) produced by reaction is equal

to the energy transferred to the surroundings from the re-

acting mass.   When this critical temperature is reached, the

mass experiences catastrophic self-heating.  This heat

transfer phenomena is a function of sample size, density, and

geometry.   As demonstrated in equation 1:^

     Cdt/dt - QVp exp (-E/RT) + hS (T - To)       (1)

     C = me (m=mass and c = specific heat)

     T = Temperature of the material

     Q = Heat of decomposition

     V = Volume

     p = Density

     E = Activation energy

     R = Gas  constant

     h => Heat transfer coefficient

     S = Surface are of the material

 As  can be  seen  from  this  equation the rate of temperature

 rise will  be affected both by the intensive properties of the

 waste, such as  density, and  the extensive properties of the

 waste, such as.  surface area  and geometry.  Since the extensive

 properties of the  sample  are likely to be different from the

 extensive  properties of the whole waste, the reactivity of

 the sample may  not reflect the reactivity of the whole waste.

     3.    The test results are in most cases subjective or
           not directly applicable.

     The ideal  test  to use in a regulatory program is usually

 one which requires minimal interpretation.  The majority of

 available  reactivity testing methods are not of the "pass-

 fail" type.  Rather, these testing methods usually produce

 test results which consist of a first order differential

 plotted against time or against a standard, from which relative

 reactivity can be assessed.  When a test of this sort is run,

 it is not run to determine "reactivity" per se but rather to

 elicit information concerning how "fast" a material reacts

 (i.e.  kinetic information) or how vigorously it reacts (thermo-

 dynamic information).  Thus,  the decision as to whether a

waste is reactive requires subjective interpretation of the

 test results.

     Additionally,  the information derived from such tests

may not be directly related to reactivity.  For example, the

test results might provide information on the activation

energy - a useful,  but potentially misleading bit of information

since it reflects the speed of the reaction rather than the

 reaction's  effects.   The  inapplicability of some of the test

 results  emphasizes  the  indefinite  meaning of the term

 "reactivity",  a  term  which  draws  its  meaning from the context

 of  its use.  A chemist  might  think of a  "reactive" substance

 as  one with  a  small activation  energy (the energy difference

 between  the  reactive  substance's  initial and transition

 states),  i.e., one which  reacts  easily.   The Agency,  however,

 unlike the hypothetical chemist,  is  not  just interested in

 things that  react "easily"  but  also  in things  which react

 vigorously.  It  consequently  needs  to take into  account not

 just the  activation energy  of a  substance but  also the  heat

 of  reaction, the molecularity of  the  reaction  and other

 factors  - information which the  available tests  often do not

 supply.   It  is,  in other words,, not  really interested in

 performing a thermodynamic  measurement,  but  rather in observing

 if  a waste behaves in such  a  way  as  to pose  a  danger  under

 normal handling  conditions.

     4.   The  standardized  methods  that  do exist  were not
          developed for waste testing.

     Use  of  the  available testing  methods on waste materials

 often results  in the  application of  standardized  methods to

 non-standardized samples and  the application of  standardized

methods  to samples with physical consistencies the method  was

not designed for.  If such methods  are used, there suits

might be difficult to interpret with  certainty.

     The avai lable reactivity testing methods  are  individually

 described  and  evaluated  in Appendix  3*.  As is evident from

 those  specific evaluations and  from  the preceeding discussion

 of  the generic shortcomings of  the available testing methods,

 none of these  "type" methods are suitable  for use to

 unequivocally.determine  if a waste presents a reactive hazard.

 For essentially the same reasons, a  numerically quantified

 definition of  reactive waste is not  feasible.  This is not as

 big a  problem  as might be thought on initial reflection.

 Most generators whose wastes are dangerous because they are

 reactive are well aware  of this property of their waste.

 Reactive wastes present  special problems in handling, storage

 and transprot.  Also, reactive wastes are  rarely generated

 from unreactive feed stocks or  in processes producing unreactive

 products or intermediates.  Furthermore, the problems posed

 by  reactive wastes appear to be confined to a fairly narrow

 category of wastes.  The damage incidents  show that the major

 problems seem  to be the  formation of hydrogen sulfide (H2S)

 from either soluble sulfides or biological degradation of

 sulfur  containing wastes, the formation of hydrogen cyanide

 (HCN)  from soluble cyanides,  and the explosion of some
*These evaluations are taken from "A Second Appraisal of
Methods for Estimating Self Reaction Hazards", E. D. Domalski,
Report No. DOT/MTB/OHMD-76-6,"Classification of Test Methods
for Oxidizing Materials", V.M.  Kuchta,  A. C. Furno,  and
A. C. Imof, Bureau of Mines, Report of Investigations 7954 and
"Classification of Hazards of Materials-Water Reactive Materials,
and Inorganic Peroxides", C. Mason and V. C. Cooper, NTIS No.
PB 209-422.  The evaluations are slightly modified so as to
determine applicability of test methods to waste materials.

 "unidentified"  waste  material.   It  will  thus  only be in a

 rare  instance  that  a  generator  would  be  unsure  of the reactivity

 class  of  the waste, or  would  be unable  to  assess  whether the

 waste  fits  a prose  definition,  ,and  would require  the application

 of  testing  protocols  to determine  the reactivity  of  this

 waste.  Since  the available testing methods  are not  ideal

 for identifying  those wastes  categorized as  hazardous due to

 reactivity, the  approach  chosen is  to prescribe a prose

 description of  reactive waste for  self-determination by

 generators  and  to list  wastes which meet this description and

 have been identified  as  reactive.

     The  prose  definition  chosen is a paraphrase  of  the top

 three  of  the reactive classes of the  National Fire Protection

 Association (.NFPA)  reactivity classification  system.   The

 other  two classes in  the NFPA c1 assificat ion  scheme  are not

 included  since  these  would include  materials  which are  inert

 under  normal handlingconditions.   This  definition is used

 because it includes all  aspects  and types  of  reactivity which

 present a danger* and is already familiar  to  persons  handling

 reactive materials.    The Chemical Manufacturers Association^-

 uses this definition  to  classify reactive  wastes  in  its

 "Laboratory Waste Disposal Manual".   Also, a  paraphrase of

 this classification system is used  by the  Navy2 in. their

hazardous waste disposal guide  and  is used in other  hazardous

materials handling guides^>^ as  a classification  system.
*A11 wastes which have been identified as having caused
 damage are identified under this definition as are  all
 commonly defined types of reactivity.


Furthermore, the States of California and Oklahoma use this

system to define reactive wastes.

1.   "Laboratory Waste Disposal Manual" Chemical Manufacturers
     Association (1975).

2.   "NEPSS Hazardous Waste Disposal Guide", Naval Environ-
     mental Protection Support Service (1976).

3.   "Handling Guide for Potentially Hazardous  Materials",
     Material Safety Management Inc. (1975).

4.   Material Data Safety Sheets.

5.   E.  J. Domalski, "A Second Appraisal of Methods for Estimating
     Self-Reaction Hazards", DOT/MTB/OHHO-76/6,  G.P.O.  (1976).

 IV.  Comments Received on the Proposed Characteristics
     and the Agency's Response to These Comments

     The Agency received approximately forty comment letters

 addressing reactivity.  These letters contained approximately

 sixty discrete recommendations or comments on the proposed

 regulation (in some letters more than one point was addressed).

 Several of the commenters felt that the proposed reactivity

 definition was adequate and provides desirable flexibility

 for the generator to use judgement.  However, the large

majority of comments expressed concern with the Agency's

 reactivity characteristic.  These comments have been categorized

by either content or the portion of the regulation addressed.

A discussion of these follows:

A.   A large majority of the comments dealt with the asserted

lack of specificity and ambiguity of the prose definition.

     0  A number of commenters argued that the prose definition

       employed by the Agency is, as a general matter,  too

       vague and should be replaced by a numerically quanti-

       fied definition accompanied by appropriate testing

       protocols.   This comment has been fully addressed in

       Part III above and need not be addressed further here.

     0  A number of commenters argued that the inclusion in

       the definition of wastes which "generate toxic gases,

       vapors,  or  fumes when mixed with water" and of "cyanide

       or sulfide  bearing wasteCs] which can generate toxic

       gases,  vapors,  or fumes when exposed to mild acidic


or basic conditions" needs to be made more specific.

Several of the commenters suggested that a phrase

such as "in harmful quantities" be inserted into the

proposed regulations as follows: "...or generates

toxic gases, vapors, or fumes in hamful quantities

when mixed with water"; "or is a cyanide or sulfide

bearing waste which can generate toxic gases,  vapors,

or fumes in harmful quantities when exposed to mild

acidic or basic conditions."  The comments on the

cyanide and sulfide bearing wastes all pointed out

that everything contains sulfides and most things

contain cyanides (albeit in trace amounts) and many

of these can generate minute quantities of hydrogen

sulfide or hydrogen cyanide under mildly acidic or

basic conditions.  The Agency is sympathetic to these

concerns,  and, in anticipation of such problems, had

attempted to make clear in the preamble and background

documents that the Agency Was leaving the determination

of reactivity hazard up to the reasonable judgement

of the generator based upon the generator's past

experience with.the waste.   Taking this conmon sense

approach,  such material as soil or flyash with sulfides

contamination (examples of sulfide and cyanide bearing

wastes supplied by the commenters) would clearly not

meet the reactivity definition.  Despite this, the

point made by the commenters is certainly valid.  There-

fore, so that there will be no confusion, the  Agency has


  changed the final regulation to make it more specific,  as

  follows:  "...or generates toxic gases, vapors  or fumes:

  in quantities sufficient to present a danger to public

  health or the environment when mixed with water; or is  a

  cyanide or sulfide bearing waste which can generate toxic

  gases,  vapors or fumes in quantities sufficient to present a

  danger to public health or the environment when exposed..."

  This would certainly better reflect our regulatory intent.

e A number of commenters advocated that the Agency specify

  what is meant by mildly acidic or basic conditions.   One

  commenter specified a pH range (5 to 9),  but offered no

  rationale as to  why this particular range should be used.

  Since a substantal percentage  of the commenters found the

  phrase  "mildly acidic or basic"  to be rather nebulous,  the

  Agency  has decided that a specific pH range should be speci-

  fied.   The pH range chosen is  that which  is considered  non-

  hazardous by the  corrosivity characteristic (2  <  pH <12.5).

  This range was chosen because  any liquid  outside  the range

  is hazardous and  requires  management within the Subtitle  C

  regulations.   Only liquid  wastes  inside this  range can  be

  landfilled without regard  to the  strictures  on  compatibility

  imposed by the Subtitle  C  regulations  and co-disposed with

  wastes  containing  soluble  cyanides  or  sulfides.   These  are

  then the most stringent  pH conditions  which a waste  could be

  subjected to outside  of  a  Subtitle  C facility.   (Natural

  waters  are unlikely  to be  outside  this  pH range).


0 Several commenters suggested that the definition of

  cyanide bearing waste should distinguish between "free

  cyanide" and ferro cyanide" since the latter would not

  be available to generate hydrogen cyanide under mild

  acidic or basic conditions.  The Agency beleives that

  such a clarification is not necessary.   If the cyanide

  is unavailable under the specified acidic or basic

  conditions then toxic hydrogen cyanide fumes.cannot be

  generated and the wastes containing these unavailable

  cyanides are not reactive.   To specify these as exemp-

  tions would be redundant and by implication might lead

  generators to conclude that other unavailable sulfides

  or cyanides NOT specifically exempted,  do meet the

  reactivity characteristic.

0  A number of commenters advocated specifying the concen-

  tration of sulfide or cyanide needed to make cyanide

  or sulfide bearing wastes hazardous.  As explained above,

  the identity of wastes which generate toxic gases under

  the conditions specified in the Definition should be

  obvious to the generator and thus,  this level of sophi-

  stication is unnecessary.

0  One commenter suggested that the Agency specify a

  rate of evolution of toxic  gas,  but included no sugges-

  tions as to how to do so.  The Agency is unsure of how

  a laboratory test method measuring  gas  evolution rate


        could be developed which could then be meaningfully

        related to field conditions.  Therefore, an evolution

        rate of toxic gas will not be included in the final

        regulat ions.

        One comtnenter argued that sulfides and cyanides should

        not be singled out in the regulations and further

        stated that all other potential toxic fume generators

        be  included or, alternatively, that no toxic fume gen-

        erators be  included.   The Agency  disagrees.   According

        to  information which  the Agency has in its possession

        (see  Appendix I),  the primary vastes  implicated in the

        generation  of toxic  gas  are  sulfides  and cyanides.  Thus,

        the Agency  would  be  remiss  if it  did  not specify thase

        types  of wastes.   If  others  are identified,  they will

        be  included also.

B.   A  number  of commenters  argued  that  the  test protocols

proposed in  Section  250.13  (c)(2)  of the  regulations  were

expensive, unreliable  and not specific enough.   Additionally,

several other  commenters had  problems  with specific  test

protocols.   (For instance, some  commeaters argued  that  the

125C temperature  adopted for the Explosion Temperature Test

was not a  reasonable  temperature and that  decomposition,  as

used in this test, needs to be defined.)

     As a  result of  some preliminary work  undertaken  by the

Agency on  the Explosion Temperature  Test*  and  after  revieving
*Evaluation of Solid Waste Extraction ?rocedures  and  Various
 Hazard Identification Tests  (Final Report)",  NUS  Corporation,
 September, 1979, (see Appendix IV).


 the  comments  received  on these test protocols* (and in view of the

 generic  problems  with  such  tests,  discussed above and in Appendix

 III),  the  Agency  has  decided  to remove the test protocols from

 261.23  of the  regulations.   The Agency agrees in general that

 they  are are  unsuitable  in  defining a "reactive" waste for RCRA

 regulatory purposes.   The Agency has accordingly removed the des-

 ignated  test  protocols  from  the regulations except to the extent

 that  the Department  of  Transportation's definition of Class A

 explosiv.es -requires  use  of  the shock instability test.  As a result

 of this  decision,  the Agency  does  not believe it is necessary to

 discuss  the individual  concerns on the various test protocols.

 C.    A number of  commenters  argued that only under landfill con-

 ditions will  a  waste be  subjected  to strong initiating sources

 or heated  under confinement.   Therefore,  they stated that since

 no landf.illing  of  explosive waste  is permitted, these conditions

 will  never occur  and Section  250.13(c)(1) (ii ) is unnecessary.

      This  argument is completely circular.   If Secti'on 250.13

 (c)(l)(ii) were removed  from  the regulations, explosive wastes

 would not  be  considered  hazardous  and could be disposed of in

 a sanitary landfill, thus subjecting the  wastes to the very

 conditions which  the commenters contend will cause the waste

 to explode.   In any event, the'Agency.does' not agree that a

 landfill is the only place in  which strong  initiating forces
*Comments were received from.the  public  on  the  proposed
 reactivity test protocols both during  the  90-dav  comment
 period on the proposed 3001 regulations  (43 FR 58956) and
 in response to the solicitation  of  corn-merits  on the  NUS report
 (Evaluation of Solid Waste Extraction  Procedures  and Various
 Hazard Identification Tests) which  was  noticed in the Federal
 Register on December 28, 1979. (44 FR 75827-76828)


or heating under  pressure  can  occur.   Pressure  increase  can

be caused by  confinement  (e.g.,  a  drum)  together  with

temperature increase  (e.g.,  caused  by  mixing) or  gas  generation

(e.g., desolubilization of  gases or  deconposit ion into  gases).

D.  A number  of commenters  advocated exempting  emergency

situations (i.e., homemade  bombs)  from coverage of  RCRA  so

that emergency  teams  can dispose of  these  explosive materials

as expeditiously  as possible without delay  (i.e.,  without

requiring a manifest, etc.).

     The regulation already makes  accommodation for cases of

imminent hazard in 263.30.  Thus,  emergency handling of

explosive wastes would be exempted  by  this  section.

E.  Other Comments

       A number of commenters  advocated  that all  the character-

       istics  be made as flexible as the reactivity character-


       The Agency disagrees with these comments;  the broad

       meaning and generic character of  the reactivity "uni-

       verse"  requires a flexible characteristic.   The Agency

       would  have preferred to define,  reactivity  by specific

       test  protocols.  However, this  is not possible.  The

       other  characterisitics, (except ignitable  solids) can

       be delineated  or  gauged by measurement of  one (or a

       few)  specific  chemical/physical properties; therefore,

       the  Agency will continue to  define the ignitable,

       corrosive,  and toxicity characteristic as  proposed.


 0 One commenter argued that just because a waste may

  undergo a violent chemical change with another waste

  is no reason to consider a waste hazardous.  To illu-

  strate this point, the commenter pointed out that an

  acid and base when mixed will undergo violent chemical

  change, but that such mixing (neutralization) is a

  necessary part of many treatment systems and should

  not be prohibited.

  The Agency believes this commenter to be under a mis-

  apprehension about the scope of the reactivity defi-

  nition.  The definition of reactivity refers to wastes

  which undergo violent change in an uncontrolled raanner

  either by themselves, or when mixed with water.  There-

  fore,  the example of neutralization given by the commente;

  is inappropriate, in as much as that example involves the

  mixing of wastes.  Furthermore, the Agency does not

  believe that the example given by the commenter is a fair

  representation of the hazards posed by wastes capable

  of undergoing a violent chemical change.   The example

  given involves the controlled interaction between two

  wastes which is a treatment  technique and thus does not

  reflect the hazards presented by uncontrolled violent

  chemical change characteristic of waste management


0 One commenter suggested that the definition of reactive

  waste  be subdivided into sections which might be later


 indexed  into a  compatibility  chart.

     The  primary  purpose  of  Section  3001 is  to identify

 hazardous  wastes,  and  not  to  dictate  management  tech-

 niques.  Section 3004  will  address  the various management

 techniques  including  incompatible wastes  (see 265.17

 of  the regulations).   An appendix to  the  regulations

 (Appendix  5  in Part 265) is provided  with just such  infor-

 mat ion.

 One  commenter suggested  that  the Agency allow a  genera-

 tor  to use  any test that is believed  appropriate  for

 determining  reactivity.  Similarly, one commenter

 suggested  that Appendix  III to  this background document

 be removed because it  might discourage  use  of a  suitable

 test .

      This comment must  be evaluated  in light of  the

 Agency's decision not  toprescribe any  tests  for mea-

 suring reactivity.  Ordinarily, when  the  Agency  pre-

 scribes a  specific test  for measuring  a characteristic,

 the  generator is free  to employ a different test  if he

 can  demonstrate, in accordance with the equivalency

 procedurees  set  forth  in Subpart E,  that  his  test  is

equivalent  to the Agency-prescribed test.   Since  the

Agency has  elected not to prescribe any test  protocols

 for measuring reactivity, the question  of equivivalent

test methods is.  largely mooted: test results  are no

 longer determinative of whether a waste is  reactive

and there is nothing against which to measure equivalency.


 This  is  not  to  say,  however,  that  the  use  of tests  by

 the  generators  is  precluded.   The  generator is  free

 to conduct  any  tests  which  aid him in  assessing whether

 his  waste  fits  within the prose definition of reactivity.

 However, the  Agency  is  not  bound  in any  way by  these

 tests  and will  make  its  assessment of  whether a waste

 is reactive by  reference to  the prose  definition.

      If  a generator  devises  a  test method  which he  be-

 lieves adequately  measures  the reactivity  of a  waste, he

 should submit that test method to  the  Agency for evalua-


 One  commenter suggested that  the Agency  address  reacti-

 vity  over time  in  the definition since a material may

 undergo  physical and  chemical  changes  as it  ages  and

 become extremely reactive, whereas  it  might  not  be

 reactive when first generated.

      The Agency agrees with  the comraenter  that  some

 materials,  such as certain ethers,  can become more  re-

 active with time.  However,   the Agency has  no information

 (such as damage incidents) concerning  any  was te s which

might present this type of problem.  Additionally,  the

Agency is not aware of any testing  method  by  which  such

wastes might be identified.   Therefore, the  final regula-

 tion will not address reactivity over  time  per  s e;  as

 these wastes are identified  by  the  Agency  they  will be

 listed in Subpart D of Part  261 of  the regulations.


        One  commenter  objected  to  the Agency defining as reactive

        those  wastes which  are  capable of detonation or explosive

        reaction  if  subjected  to  a strong initiating source or

        heated under confinement.   The commenter asserted that

        many inert,  non-reactive materials,  including tap water,

        can be triggered  to  detonate  or explode under confinement

        when subjected  to strong,  heat,  pressure,  or a combination

        of these  and other  initiating sources.

            The  Agency disagrees  with this  coTamenter and takes

        specific  issue with  the assertion that  many  relatively

        inert  substances  could be  made to explode  when subjec-

        ted to  extreme heat  and pressure.  In any  event,  even

        if relatively inert  substances could be made to explode

        when subjected to strong heat  and pressure,  these sub-

        stances would not be considered  reactive under the  pro-

        posed  definition.  The Agency  is  only concerned with

        substances capable of exploding  under reasonable  confine-

        ment conditions -- i.e., those  confinement conditions

        likely  to be encountered in disposal environments.

V .    Promulgated Regulations

     As a result of EPA's review  of  the  comnents  regarding

the reactivity characteristic, EPA is  promulgating  a  reactivity

characteristic which significantly differs  from the proposed

regulations  in two aspects:  the  thermal  instability  and shock

instability test protocols  cited  in  the  proposed  regulation

has been removed and the sect ion  relative to generation  of

toxic gas, hydrogen cyanide and hydrogen  sulfide has  been


 made more  specific.   The  thermal  instability  test  protocol

 was removed  because  the Agency  determined  that  its  interpre-

 tation  was too  subjective  for use  in  a  regulatory  program*.

 (See Appendix  IV) .

 261.23  Characteristic of  reactivity

     (a)   A  solid waste exhibits  the  characteristic  of  reactivity

 if a representative  sample  of the  waste  has any  of  the  following


 (1)  It is normally  unstable and  readily undergoes  violent

     change  without  detonating.

 (2)  It reacts  violently with water.

 (3)  It forms potentially explosive mixtures  with water.

 (4)  When mixed with  water, it  generates toxic gases, vapors

     or fumes in a q'uantity sufficient  to  present danger  to

     human health or  the environment.

 (5)  It is a cyanide  or sulfide bearing  waste which, when ex-

     posed to conditions of pH  between  2 and  12.5,  can  gen-e

     erate toxic gases, vapors  or  fumes  in a  quantity suffi-

     cient to present danger to human health  or  the  environ-

     ment .

 (6)  It is capable of detonation or explosive reaction  if sub-

     jected  to  a strong initiating source  or  if  heated  under


 (7)  It is  readily capable of detonation or explosive decompo-

     sition or reaction at standard temperature  and  pressure.
*"Evaluation of Solid Waste Extraction Procedure and Various
Hazard Identification Tests" , (Final Report), NUS Corporation,
September, 1979, (Appendix IV)


(8)  It is a forbidden explosive as defined in 49 CFR 173.51

     or a Class A explosive as defined in 49 CFR 173.53,  or

     a Class B explosive as defined in 49 CFR 173.88.

     (b)  A solid waste that exhibits the characteristic  of

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

D, has the EPA Hazardous Waste Number D003.

                          APPENDIX I


                      OF REACTIVE WASTE

1.   Santa Cruz, California - A bulldozer operator was overcome

by hydrogen sulfide (H2S) fumes generated while mixing tanning

wastes with other wastes.  (Four deaths have occured in

California between 1963-1976 from inhalation of H2S from

waste tanning sludge.

2.   Baltimore County, Maryland - Six nen were hospitalized

due to the inhalation of hydrogen sulfide gas liberated from

salts being landfilled.

3.   Edison Township, New Jersey - A bulldozer operator was

killed at a landfill when a barrel of unknown waste exploded.

4.   Crosby, Texas -Residentsin-the area were subjected to

sore throats,  nauseau, and headaches when toxic fumes were

released from the reaction between oily wastes and acids,

dumped in an abandoned sand pit (twenty-six wells were closed

by this  incident).

5.   Edison Township, New Jersey - Cases of conjunctivetis ,

eye irritation,  burn on cornea, and chemical burns resulted

from reactive wastes being landfilled.

6.   Northern California - A drum of toluene ciisocyanate

(TDI) exploded,  spreading extremely toxic toluene diisocyanate

throughout the area.

 7.   Los Angeles,  California  -  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  thousan'ds gallons of acid waste at  the sane

 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.

 8.   California -  Sulfide waste was added  to s.oluble  oil

 waste in a tanker  and subsequently added to other oily wastes

 in a tank.  Later  treatment fo  the oil with acid to break the

 emulsified oil resulted in the  evolution of hydrogen  sulfide.

 Two operators were briefly affected by the gas.  There was

 also an explosion  in the tank.

 9.   Dundalk, Maryland - At a. sanitary landfill near  Dundalk,

Maryland^ a 2,000-gallon liqu.id 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 firefighters 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 13 when measured before

 it left the  plant).

 10.  Los Angeles,  California - When  the laboratory  drain  at a.

 Los Angeles  hospital was being cleaned by  scraping,  the drain

 pipe exploded scattering fragments  of aetal from  the pipe.

 Two subsequent attempts to remove  the  residual piping with

 screwdriver  and hacksaw resulted in  explosions in both

 instances.   Fortunately, no one was  injured in these explosions.

 The cause was later attributed to  shock, sensitive lead azide

 formed in the lead pipes.   A test  solution, containing sodium

 azide as a preservative, was routinely poured  into  the sewer

 drain line after use.   This chemical accumulated  in  the pipes

 and reacted  with the lead in the pipe  to forn  shack-sensitive,

 explosive crystals of lead azide.

 11.  Riverside County, California -  Several drums of phosphorus

 oxychloride, phosphorus thiochloride and thionyl  chloride

 (all oxidizing agents) were improperly dropped off  at1 a dump.

Later,  during a flood, the drums were unearthed,  ruptured, 

 and washed downstream, releasing highly toxic hydrogen chloride

gas and contaminated the water.

 12.  California - A disposal site in central California

accepted a load of solid dichroaate  salts  (oxidizing agents)

and dumped it into a pit along with  pesticide formulations

and empty  pesticide conainers.   For  several days  thereafter,


 snail  fires  erupted  in  the  pit  due  to  the oxidation of  the

 pesticide  formulations  by the dichromate.  Fortunately,  the

 site personnel were  able to extinguish these fires before

 they burned  out of control.

 13.  Southern California -  A company using toluene diisocyanate

 (TDI)  in the manufacture of plastic and foam rubber automobile

 products collected and  stored its TDI wastes on-site in  55-

 gallon metal drums with clamp type  lids.  After an extended

 period of  time during which thirty  such drums had been

 collected, a hauler  was contacted to transport the wastes to

 a Class I  site in Southern  California.  The hauler stored

 these drums  in an open  area at his  facility for approximately

 two weeks.   Heavy rainfall  occurred during this period.  Upon

 arrival at the disposal site a violent explosion ruptured one

 of the drums.  There were no injuries associated with this

 incident.   During storage some water apparently condensed or

 leaked into  the drums through the clamp-type lids.  Transportation

 of the drums then provided the agitation to accelerate the

 reaction between water  and TDI.  The rapid production of C02

 caused extreme pressure build-up on one of the drums and

 subsequent violent rupture.

 14.   Southern California - In 1972 at a disposal site in

 Southern California,  reaction of sodium chlorate (oxidizing

 agent)  with refuse started a fire which lasted for two hours.

There were no injuries associated with the incident.

Dirt contaminated with NaC104  (oxidizing agent) was drummed

and tranported as "Nad" to the sanitary landfill.  The drums

were emptied onto re.fuse.  The contents of the drums were wet

but reacted with the refuse to cause a fire upon dumping out.

A similar incident involving NaC104 and refuse producing a

fire occured in 1973.  This incident involved containerized

material that reacted with refuse when a container ruptured

during the covering operation.

15.  Southern California - A' standard procedure at a Southern

California disposal site for handling cyanide-bearing liquid

wastes 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

defected low levels of 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 apparently formed in the well as a result of

lowering of the pH of the waste by carbon dioxide and organic

acids produced in the decomposition of refuse.

16.   A delayed reaction between phosphorus oxychloride (oxidizing

agent)  and water in a 55 gallon drum caused violent rupture

of the  durm and killed a plant; operator.   The steam and

hydrogen chloride gas generated by the reaction caused the

explosion which propelled the bottom head of  the drum

approximately 100 yards from the scene.

                          APPENDIX  II


 1 .  Texas
The Texas Water  Quality  Board  uses  the  following  definition:

"Industrial Hazardous Waste" means  any  waste  or mixture  of

waste which ...  generates  sudden  pressure  by  decomposition,

heat or other means  and  would  therefore  be  likely  to  cause

substantial personnel injury..."  -  in combination  with a listing

of 40 compounds.

2.  State of Washington

Defines explosive using  a  5" drop test,  or  class A explosive

(see DOT) definition.

3.  P ennsyIv an i a

Combines Flammables  and  Explosives  and  uses only  the  following


          (1)   Munit ions

          (2)   Blasting  Materials

          (3)   Pressurized Cans

          (4)   Paint Thinners

          (5)   Solvents

          (6)   Kerosene

          (7)   Oils

          (8)   Petrochemical Waste  Sludges

          (9)   Petroleum Waste Sludge

4 .   California

Uses the following definition:


      "A waste,  or  component  of  waste  is  considered  pressure

 generating  or  reactive  if  it:

      1)   Is a  Forbidden or  class  A,  B,  or  C  explosive  as  de-

          fined  in  Title 49  CFR, Sect ions  173 . 51, 173.88,

          and  173.100 respectively (see  DOT).

      2)   Is a  water reactive material.

      3)   Is in  NFPA category 2, 3, or 4  (see  NFPA)".

 5 .  Illinois

 Uses  the  following  definitions:

      "Explosives" - Any waste having  concentration  of 1 % or

 more  of a substance described as an explosive  (high,  low,  or

 permissible) by  Sax (Dangerous  Properties of Hazardous  Materials

 by N.  Irving Sax, Van Nostrand  Reinhold)  shall be considered

 as explosive "per se".

      "Reactives" - Any waste having a composition of  5% of more

 of a  substance that (as described  by Sax) readily reacts

with  air,  water, or other substances to produce heat  and/or

 toxic  fumes  shall be considered a  reactive waste.   The  definition

 includes oxidizing agents.

6.  NFPA

          Category 0 -  Materials which in themselves  are nor-

                       mally stable, even, under fire  exposure

                       conditions,  and which are not  reactive

                       with wat  er.

          Category 1 -  Materials which themselves are normally

                       unstable  and readily undergo violent

                       chemical  change but do not detonate.


                       Also materials  which may  react  violently

                       with water  or which may  form  potentially

                       explosive mixtures with  water.

          Category 3 - Materials which  in themselves are  capable

                       of detonation or  explosive  reaction  but

                       require  a strong  initiating source or

                       which must  be heated under  confinement

                       before initiation or which  react explo-

                       sively with water.

          Category 4 - Materials which  in themselves are

                       readily  capable  of detonation or of

                       explosive composition or  reaction  at

                       normal temperatures, and pressures.

7 .   DOT

The Department of Transportation lists  explosive wastes (these

are typically propellants, explosives,  initiating  compounds

etc.) and also specifies testing methods for liquids and

solids unstable to thermal and  mechanical stresses.  (See 49

CFR 173.53) .

                       Appendix  III

     The testing methods examined  in  this section* are

separated  into tests  for thermal instability,  (Tests I thru

X)  tests for  impact mechanical shock  instability  (Tests XI a

and b) tests  identifying oxidizing agents,  (Tests XII thru

XIV) and a  test identifying water  reactive materials (Test

1.   Most of the information contained in this Appendix was
taken from "A Second Appraisal of Methods for Estimating Self
Reaction Hazards" E.S. Domalski Report No. DOT/MTB/OHMO-76/6.

A.   Tests Identifying Wastes Unstable to Thermal Stress

    I.    JANAF (Joint Army Navy Air Force) Thermal Stability Test

    Number Six for Liquid Propellants.

    1.    Purpose of Test:

         To determine the maximum temperatures to which thermally

    unstable liquids can be subjected for short periods of time

    without danger of explosive decomposition.

    2.    Operating Principle:

         Under confinement in  a microbomb,  a liquid sample is either

    heated rapidly and held at  a pre-determined temperature for

    an  arbitrary time interval, or heated at a constant rate until

    evidence of rapid decomposition appears.  Spot immersion is

    also  possible,  where th'e microbomb containing the sample is

    immersed into  the bath at  some elevated temperature.

    3.    Test  Description;

         A microbomb which is  drilled and tapped for  a thermocouple

    and burst  disc  fitting,  has an internal volume of 1.3  cm^.   A

    liquid sample  of 0.5 ml  volume is used  and burst  diaphrams

    ranging  from 300 to  8400 psi failure pressure can be  used.   The

    microbomb  is immersed  in a  bath  containing a bismuth-lead alloy,

    which  melts  in  the  range of 65.6C(150F) to 12 1 . 1 .C ( 25 0  F ) .

    Maintenance  of  the  bath  around 93 .3C (200"F) and of  the

  .heating  rate at  -6.7eC  (20F)  per minute, allows  detection

    of the  rate  of  decomposition of  -16.7C  (2" F) to  -1'5'C (5F)

    per minute.  An  air-vibrator is  used to  agitate  the bath and

    the sample  in  order  to  establish  the desired.heat transfer


 between  bath  and  sample.   The  sample  temperature  and  the

 temperature difference  between the  bath  and  sample  are  recorded

 as  a  functions  of  time.   The  temperature at  which self-decompo-

 sition begins  and  the rate  of  decomposition  can be  derived.

 4.    Test Evaluation:
     This  test  utilizes  small  samples  of  material  in  good  thermal

contact with  thermostated  suroundings.  The  temperature  of the

sample can be increased  with time  at such a  slow rate  that

quasi-steady  states  are  maintained.

     Rates of decomposition can be  estimated  from  plots  of the

sample temperature vs. time, and from  plots  of  the  temperature

difference between the sample  and  bath vs. time.   The  slope  of

the temperature differential curve  represents  the  rate of  heat

transfer between the sample and the bath.  Factors  which need

to be taken into account are the rate  at  which  the  bath  is  being

heated, heat ing from the self-reaction of the  sample,  and

temperature gradients in the microbomb.   From  a plot of  the

self-heating rate of the sample vs. the reciprocal  of  the

temperature, a  linear slope proportional  to  the activation

energy should result.  The precision of activation  energies

derived in this manner is about +_  15 percent.

5.   Applicability, of Test as an Index of  Waste Reactivity:

     The activation energy of  the reaction in quest ion, while

certainly an important parameter in assessing waste reactivity

 (as discussed  previously)  is  not  the only parameter.

 Also  important  are  heat  of  reaction, waste geonetry,

 density; the heat  transfer  etc.   To  indicate a particular

 activation energy  as  a cut-off  for waste reactivity would

 result  in many  false  positives  and negatives.

 II.  ASTM \(_Am_erican So^ie_ty f^or JTe_s_t ing_and_Mater ials)  Standard

     Method of  Test E-476-73^ Thermal I_ns tability_of Con-

     fined Co_nde_nse_d  ^hase  Sys_te_ms_( Confinement T^est)

 1.  Purpos^e of  T_est:

     To determine  the temperature at which a checical mixture will

 commence reaction,  liberating appreciable heat or pressure,

 when subject to a  pro-grammed  temperature rise.  This method

 applies to solids or  liquids  in a closed system in air  or some

 other atmosphere present initially under normal laboratory


 2 .  Ope_rat_ing_Pr i ncip_lej

     The sample to  be tested  is confined in a  closed vessel

 equipped with a burst diaphram, pressure transducer, and

 thermocouple.   The  apparatus  is equilibrated in a bath  at

room temperature and  subsequently heated at a  constant  rate.

The temperature difference  between the  bath and sample,  the

pressure in the closed vessel, and the  bath temperature  are

recorded continuously during  the  course of  the test.

 3 .    Test  Description;

      This  apparatus  is  a modification of that described under

 the  JANAF  Thermal Stability Test.   The sample (300 rag.) is

 placed  in  the  test  cell  or  vessel  (volume 1 cm')  and is in

 intimate contact  with  a  thermocouple.   The apparatus also has

 a burst diaphram-vent  tube  system  to release gases formed during

 decomposition  if  the  pressure  reaches  too high a  value, and a

 pressure transducer  to  provide measurement of the total pressure

 inside  the  vessel as heat  is  supplied  from a bath at a. constant

 rate.   The  nominal heating  rate of the bath is 8 *C (46.4F)

 to 10C (50"F)  per minute.   Silicone oil is used  in the

 range 0" C  (32*F)  to  370C  (698F)  and  a low-melting alloy

 (i.e., Wood's metal) in  the range  100C (212eF)  to 500C  (932F).

 Recorders  are used to ..monitor,  firs.t,  the difference between

 the  sample  temperature,  (T)  and bath temperature, (Tg)  as a

 function of bath -temperature,  and,  second,  pressure, (P)  as a

 function of bath  temperature.   No  agitation is used so  as to

 minimize thermal  lag.

 4 .   Test Evaluation:

     The threshold temperature  is  the  lowest temperature  at the

 left hand base  of the positive  peak  which appears in the  plot

 of (T)-(TQ) vs  TO .  The  threshold  temperature is  an indication of

 the onset of thermal instability in  the sample.   A potential

hazard exists,  therefore, when  the  temperature of the  sample

 exceeds this value.  The instantaneous  rate of pressure versus

bath temperature, the maximum  pressure  generated  and the  rate

 of pressure rise  are useful hazard  parameters  related  to  rough

 approximations  of reaction  time, and damage potential.


      Examination  of  the  rate  of  temperature  rise  of  the

 sample,  (dT/dt) and  rate  of temperature  rise  of  the  bath  '(dT0/dt)

 not  only  allows an evaluation  of  the  Arrhenius constants,  but

 also  provides  for arbitrary scaling  of  the process.   A simpler,

 and  probably preferable  procedure, may  be  to  record  only  TQ

 corresponding  to  a runaway condition  (e.g..  a. specified value

 dT/dt dTo/dt,  or  rupture  of a  pressure  disk  (there  is some

 arbitrariness  in  the  definition  of the  runaway criterion,  but

 this  feature may  not  be  serious)), and  then  repeat  the experiment

 with  a different  sample  diameter, d.  The  Frank-Kamenetskii

 condition then gives  the  value of E  from

          (dl/d2)2 =  (Toi/To2)2  exP  (E/R)  (1/Tol~1To2U-

 This  procedure obviates  the necessity of evaluating  A and IN , and

 allows immediate  seal-ing  to any  size.

 5.    App_licab_il_ijty of_Tej_t_ a_s_  an _Ind_ex_of_Waste_ Reactivity:

      This test suffers from the  same  drawbacks as the JANAF

 test, i.e., the activation energy obtained from the  test

 is not a definitive  indicator  of waste  reactivity.


      This test is run under adiabatic conditions.   Conditions  of

 this  sort do not correspond to normal waste management conditions,

 and thus the test results are  not likely to be reflective  of actual

waste reactivity.   Since  different information cannot be  obtained

from  this test than  is already available from tests  I and  II,  a_n_d

the test conditions correspond less to waste  management conditions

than do tests I and II, no further evaluation of  this test is

presented here.



1.   Purpjpse of Test1.

     To determine explosion  temperature  (temperatures  for

which there is a delay time  of 250 sec before  explosion).

2.   Operating Principle:

     The discharge of a  capacitor across a  thin-walled  tube

provides the thernal stimulus to initiate explosive decomposition.

The time-temperature profile of the decomposition  is obtained

from oscillographic records.  Although the  tubes are thin-walled

(0.089 mm), they have considerable strength and provide  a  state

of heavy confinement for the explosive or unstable material.

3.   Test_Description:

     A test sample is loaded into hypodermic needle tubing which

is heated, essentiall-y instantaneously,  by  a capacitor  discharge.

The temperature and time of  the explosive event are recorded

from a continuous measurement of the electrical resistance of

the tubing by means of an oscilloscope.  The test  is particularly

suited to liquid material but solids can also  be accomodated

by melting prior to their insertion into the hypodermic  needle

tubing.   Materials are subject to temperatures in  the range of

260C (500F) to 1100C .(2012F) and delay  times of 50  in

sec. to 50  sec.   The delay  time, T is given by A  exp (B/RT)

where A and B are constants  (somewhat related  to the Arrhenius

pre-exponential factor and activation energy), R is the  gas

constant,  and T is the absolute temperature.

4.   J_es_t Ev au 1 j_t_i on :

     The thermal surge test  supplies data on explosion


 temperatures which  represent  conditions  of minimal heat  transfer.

 This test measures  the true induction  tine of an explosive  rather

 than the time  required to heat up  the  sample.  Wenograd  15

 was able to show a  correspondence  between the temperature of the

 system 250 sec prior  to explosion  and  impact test data.  The

 activation energy parameter obtained in  thermal surge test

 measurements under  dynamic conditions  are considerably lower

 than those determined in other measurements under isothermal

 conditions.  This test is probably one of the best available

 approximations to a point source heat  initiation of an unstable

 material in a multicomponent  system.

 5.   Applicability  of Test aj_ an Index of	Was_te	Reactivity

     The high temperatures the test materials are subjected

 to in this test do  not correspond  to the temperatures which

wastes might be subject to during  management (unless the

waste is subject to a strong electric  discharge).  For this

 reason, this test is unacceptable.


     Like test III, this test is run also under adiabatic

conditions, and therefore no further evaluation is presented.


     This test determines the heat generation rate as a  function

of time and estimates the induction period at a given temperature

for a material.  This test is run  under  isothermal conditions

and takes anywhere  from weeks to months  to complete.   For these

reasons,  no further evaluation is  presented.



1.    Purpose  of T_est

      To  determine  the  temperature  at  which  a  material  explodes,

ignites, or decomposes after a five second  immersion in a Wood's

metal bath.

2.  Operating_Principle

     This  test gives an  estimate of how close  the  explosion

temperature is to  ambient condition for a material, and, hence

provides a measurable  indication of thermal instability.

3.   Tet Description:   

     The material  to be  tested (25 mg.) is  placed  in a copper

test tube (high thermal  conductivity)  and immersed in  a Wood's

metal bath.   This  test is made at  a. series  of  bath temperatures,

and the time  lag prior to explosion at each temperature is recorded.

The bath temperature is  lowered until  a temperature is reached a-c--"

which explosion, ignition, or apparent decomposition does not occur.

The bath temperature working range is  from  about 125C (257F)

to 400C (752F).   The sample is removed from  the  bath after

5 minutes if  no explosion has occurred at 3608C (680F).

4.   Test Eva_luji_t^on:

     The explosion time  is very nearly independent of  sample

size provided, the sample size is in the range  10 to 40 mg.

Particle size is also important in providing consistent re-

sults  for a group of materials.   Rapid equilibration of the

sample upon contact with the high  tenperature  bath will depend

upon the heat capacity and thermal conductivity of the material,

 and  could  be  a  major  uncertainty in the test.   Explosion tempera-

 ture  data  is  a' function  of  time  and serves  as  useful indicators

 to assist  in  maintaining safe  thermal  conditions  during handling

.and  transport.

 5.    Applicability  of  Test  as  an Index  of Waste Reaetivity:

      This  test  would  seem the  most  suitable  for our purposes.

 The  test results  are  pass-fail,  either  an explosion, ignition,

 decomposition etc.  takes place or not.

      Problems  do  arise out  of  distortion of  thermal transport

 from  sample size.   However,  this is a  problem  with  all  tests.

 Also  the Woods  Metal  Bath  results in Cadmium fumes  being generated

 and  should only be  operated  in a hood.  A sand  bath or  nonflammable

 oil bath might  be more suitable  for our purposes.

      Field testing  of  this  method indicate  that it  is unsuitable

 for use without other modifications (see Appendix IV).


 1.    Purpose  of Test;

      To determine the self-heating  of  a sample  at small to

moderate heat generation  rates as a function of temperature

or t ime.

2 .    Operating Principle:

      A cylindrical  aluminum block contains  a cavity which  has

a Peltier element attached  at the bottom and a  sample is  placed

on the Peltier element.  Heat flow  from the  block to the  sample

is measured by means of  the Pe1tier e1ement  which provides

an'electrical  signal  to  a  recording  device.

3.   Test Description:

     A sample  vessel  constructed  of  stainless  steel  (volume,

2 cm^) is positioned  over  a Peltier  element, and  both  are

housed inside  the  cavity of a  cylindrical  aluminum block.

This central block is surrounded  by  mantles containing  elec-

trical heating  elements  in addition  to  an  insulating  layer.

The electrical  input  to  the block and mantles  is  maintained

in  such a manner as to keep the temperature difference  between

the block and  mantles as small as possible while  the  block is

heated linearly at about 108C  (50F) per hour.  The heat flow

from the aluminum block  to the sample is measured by  the

Peltier element.  As  soon  as the  sample begins  self-reaction

the heat flux  to the  sample starts to decrease.   From  a plot
of  the heat generation of  the  sample vs. the reciprocal of

the absolute temperature,  the  activation energy can be  calculated.

4.   Test EvaJUiatij3n_:_

     Changes in the heat capacity of the aluminum block over the

temperature range 20C (68F)  to 200C  (392F) will cause the

temperature increase over  this range to be slightly non-linear.

The Peltier element is temperature dependent, and calibration

using a pure copper sample having known thermal properties is


5 .   Ap p Li_c_ab_il_ity of T_es t_as an _Index_o_f_Waste Re a c t i v i t y

     This test yields activation energy and is, as a  result,

subject therefore to the same  drawbacks as tests  I and  II.


 IX    Homogeneous Explo_sion_Test

 1.    Purpose of Tes_t:

      To  determine  the pressure-time profile of the  thermal

 explosion  of solid or liquid materials.

 2.    Operating Principle:

      A sample is heated under adiabatic conditions  in a closed

 vessel until explosion occurs.  The maximum rate of pressure rise

 and the  maximum overpressure are measured as a function of

 time  at  different heat input rates.

 3.    Test__Description_:_

      About 100 ml of a sample is introduced into the lower part

 of a  stainless steel vessel. The lower section is sealed off

 from  a larger upper section above by a membrane (breaking

 pressure 1 bar).   The larger upper section serves as a free

 space for  the expansion of reactant or product vapors.

 During the main part of the induction period,  pressure equali-

 zation is  accomplished by a capillary tube connecting the

 upper and  lower sections of the vessel.   The two-compartment

 vessel is  placed inside a larger vessel of 20 liter capacity

 which seals the former from the external surroundings.  A

 heating mantle around the latter vessel allows heating of the

 inner vessel to take place as near to adiabatic conditions

 as possible.   Around the sample vessel there is also an

auxiliary heater  which heats the sample at a constant (but

adiabatic)  rate until explosion occurs.   When explosion

takes  place,  the  membrane is ruptured and expansion into the

larger volume takes place.  A piezo-electric pressure transducer


 records  the  pressure  prior  to,  during,  and  after  explosion.

 4.   Test  Evaluation:

     Differentiation  of materials which give  large rates of

 pressure rise and  overpressures  can be  singled  out from those

 which give low values.  Subsequent precautions  for management

 can be taken.

 5.   Applicability of Test  as an Index  of Waste Reactivity;

     This  test identifies those  wastes  which  react under

 thermal  stress to  produce la.rge  pressure gradients.  This

 information  could  be  of use to  identify potentially reactive

 wastes, hazardous  due to pressure generation.   This type of

 reactive waste would  also be identified by  the  explosion

 temperature  test since some part of degradation or change  in

 the sample would be apparent for the samples  failing this  test.

 X.   Differential Thermal Analysis (DTA) Test

 1.   P_urj>jos_e_ of Test:

     To determine  exothermic and eadothermic  reactions in  a

 material as  heat is applied at a particular input rate.

 2.   Operating-Principle;                   l

     The material under test and a stable reference material

 are heated simultaneously at the same rate.   Exothermic and

 endothermic  traces are measured  using a recorder  providing a

 temperature-time plot of the reaction process.

 3.   Test Description:

     The material to be tested (5 to 25 mg) and a. reference

material (such as alumina or glass beads) are placed into

 identical compartments in an aluminum block.  Heat is supplied


 to both  compartments  at  the  same  constant rate  of  input.

 Temperatures are measured using therno-cocples  in  conjunction

 with automatic  recording devices  so  that a plot  of  temperature

 vs. time is obtained.  A shift in  the  base line  results  from a

 change in  the heat capacity  or mass  of  the naterial under test.

 Particular care must  be given to  the type of  temperature sensor

 used and to the choice of its location, in the conpartment inside

 the aluminum block.   The geometry  of the sanple  and thermal

 characteristics (such as thermal  conductivity)  of  the  sample

 will affect the shape of the DTA  curve.

 4.   Test_Ev_a_luation_:_

     From  the exotherms and  endotherzs  of the DTA  curve,

 decomposition temperatures corresponding to various rates of

 temperature rise can ~be obtained.  Kinetic parameters  can be

 calculated as a result of properly varying the heating rates

 and assuming a constant degree of  conversion  of  reactant when

 a specific thermal event (such as  the peak temperature of a

 given exotherra) takes place.  When the  temperature sensors are

 placed in the path of the heat flow the DTA apparatus  can

measure the enthalpies of processes such as heats of deconposition

 or transition.          .

5.   Applicability of Test as an Index  of Waste Reactivity:

     This test  will give information as to how a waste reacts,

 thermally,  to thermal stress.  There are several problems beyond

 those  normally  associated with test's of this kind:

     (1)   The stress   is specialized, as is the reactivity

     inf orinat ion.


          (2)  The test must be interpreted, and is sometimes

          ambiguous (as in the case where several reactions are

          taking place, one of which is eadothermic e.g. decomposition

          of NH4N03).

          (3)  Usually very small samples are used, which makes

          getting a representative sample even more difficult.

     On the other handj this is a .standardized procedure which is

     familiar to industry, widely known and often used.

B.   Tests for Reactive Wastes Sensitive to Mechanical S_tr_e_ss

          A great many sensitivity tests using mechanical stimuli

     have been devised, mostly by the military, hence generally

     intended for the  rating of sensitive energetic materials

     (explosives and propellants).  Since we are interested mostly

     in waste commercial materials or b--?roducts of lower sensitivity

     (although handled in larger amounts), the raain problem is to

     select a few suitable tests from the large number of existing


     XI .   Impa_c_t_Te_s_t

     1.   Purpose of .Te_s_t ^

          To determine the minimum drop height of a falling weight

     which strikes an  explosive material and produces either a mild

     or violent decomposition reaction.  Both falling weight and

     explosive material have a fixed and constant mass.

     2.   Operating Principle:

          Impact energy is supplied to an explosive by a weight, of

     constant mass which is dropped fron varying heights to establish

     the  minimum height to providedetonation, decomposition, or


charring.  The impact provides rapid  compression and crushing

of the sample (which may involve a frictional component  of

crystals rubbing against crystals) and detonation ensues.

3.   T_est De_sc^rj.jrtion :

     The two most prevalent impact tests are those by  Picatinny

Arsenal (PA) (Test XI a) and the Bureau of Mines (3M)(Test XI  b).

     In the PA apparatus a sample is  placed in the recess of a

small steel die cup, and capped with  a thin brass cover.  A

cylindrical steel plug is placed in the center of the  cover,

which contains a slotted-vent and the impact of the 2  kiram

weight is transferred to the steel plug.

     In the BM apparatus a. 20 rag. weight is always employed while

the PA sample size may be varied for  each experiment.  The explosive

sample is held betwee'n two flat parallel plates made of  hardened

steel and impact is transmitted to the sample by means of the

upper plate.   Sample decomposition is detectable by audible,

visual or other sensory means.

     In an apparatus used by the Bureau of Explosives  (part

of the Association of American Railroads) and cited in Title

49 CFR (DOT Hazardous Materials Regulations) a falling weight

is guided by a pair of rigid uprights into a haamer-anvil

assembly containing a 10 mg. sample of explosive.  Reproduci-

bility can become a problem here because of a non-ideal

collision between the drop weight and the impact hantaer  since

only  a fraction of the drop-weight energy is transmitted to

the sample.

     4.   Test Evaluation:

          Greater confinement of the sasple will limit the translational

     component of the impulse to a smaller area as is the case with

     the PA apparatus.  Factors which play an influential role in

     the test are:  materials of construction, sample thickness, sample

     density, hammer geometry, mass of drop weight, impact area,

     surface finish, the surrounding atnosphere, temperature, and

     pressure.  Modifications can also be made to accomodate cast

     and liquid samples.

     5.   Applicability	of These Tests^as^Indicies of Waste Reactivity;

          Impact tests suffer from the drawback that the fundamental

     processes leading to energy release are complicated and poorly

     understood.  Failure of good agreement between various impact

     tests shows that these tests contain uncontrolled parameters.

     On the other hand,  (1) partial correlations do exist, (2) the

     history of the test indicates rough agreement with field

     experience, (3) the stimulus is of reasonable severity,  (4) the

     tests are widely known and realtivelj easy to use.  These facts

     make them useful for a partial definition of hazards.

C.    Tests Identifying Oxidizing Wastes^

     XII . Burning Rate Test for Solid Oxidizers^

     1. .   j? ur_p_oj_e of Tes tj_

          To determine the relative fire hazard present when in-

     organic oxidizers are heated in the presence of wood or  cellulosic

     subs tances.

     2 Most~o~fthe information contained in this section was  taken
       from "Classification Test Methods for Oxidiz.ing Materials"
       by J. M. Kutcha,  A. I,.  Furno,  and A. C. Imhof,  Bureau  of
       Mines,  Report of  Investigations 7594.


 2.   Operating  Principle:

     A  set  sample  size and  ratio  of dried  sawdust  (12-50 nesh)

 and oxidizer  is  ignited and  the burning  rate  is  determined by

 measuring the time  for the  burning to  propogate  at least 5 inchest

 3.   Test Description

     For the  test,  sawdust  is initially  screened to provide

 particles ranging  in size from 12 to 50  mesh  (Tyler screen

 series).  The sawdust is dried in an oven  at  101.5C  (215F)

 + -15C (5F) for  about six hours, and then test mixtures

 having various  concentrations of  the oxidizers are prepared.

 To obtain a uniform mixture, the materials are agitated for

 10 minutes  or more  in a closed container.  Generally,  fine

 oxidizers are used  "as received" but coarse oxidizers can be

 pulverized  and  screened to obtain sanples  at  least as fine

 as the wood sawdust.  For most of the oxidizers, a particle

 size range  of about 20 to 100 mesh appears to be adequate

 for determining their hazard classification by this proposed

 test.   However, where the hazard level of  such materials is

uncertain because of particle size considerations,  the burning

rates  of the mixtures should also be determined using oxidizer

samples that have fractions finer than 100 mesh.

     Burning rates are measured using a  rectangular rack that

was mounted horizontally and equipped with a  60-nesh  steel screen

to support  the sample.   The sample bed is  separated fron the side

rack nounts  to insure unrestricted .burning along the  sides of the

 sample.   To  form the sample bed,  the sawdust-oxidizer mixture

 is  placed on a  rack  between a pair of spacer bars vhich fixed the

 bed  size  and which  are  removed before ignition.  The bed can also

 be  formed in a  U-shaped wire screen channel which is transferred

 onto  the  burning rack;  the  wire screen channel is then removed

 before ignition.  The  sample is ignited by a. propane torch or

 similar flame source and the burning rate determined by

 measurements  made with  two  fuse wire (0.5 anp) stations

 and  an electric  timer,  although slow-burning nixtures can be

 followed  visually and  timed with  a stoowatch.   The sample bed

 was  normally  7  inches  long  and the rates are measured over a

 distance  of  5 inches and at least  1 inch from the ooint of


 4.    Test  Evaluation:
     This proposed  test method  permits  classification of solid

oxidizers into  two  or more  groups  based on their relative

burning rates with  a cellulose-type  cotnbustible such  as  wood

sawdust.  The least hazardous class  includes  those  oxidizers that

burn at low rates 10 in/min)  when  aixed  with  the  select-grade,

red oak sawdust.  A second  class consists  of  oxidizers,  such as

the alkali nitrates and chlorates, which burn at relatively high

rates (>10 in/min) when mixed with this sawdust. A third,  more

hazardous class should include  those  oxidizers, which when  un-

mixed or mixed  with a combustible, might ignite spontaneously

and burn vigorously if moisture  is present or if they are heated

slightly.  This class would include sodium peroxide and calcium

hypochlorite (69.5 percentage C12) which gives very high burning

rates with the sawdust.  A fourth class is also required for those

oxidizers, such as ammonium perchlorate, which may detonate

when heated under confinement or when exposed to shock.

5.   Applicability of Test a_s_ a_n Index of Waste Oxidizing


     This method is designed to provide a relative measure of

the increased ignition or burning hazard that may exist when

inorganic oxidizers are mixed with an organic substance such

as sawdust.  They are not applicable to organic peroxides or

to inorganic oxidizers that may detonate when heated with or

without a combustible.

     In the application of this test method, it must be recog-

nized that a reliable hazard rating may not be possible for

all oxidizers using a single reference combustible.  If the

adjacent material is not cellulosic in nature, (and in a

landfill this may or maynot be the case) it is conceivable

that an oxidizer may display a greater level of hazard than

observed with the select-grade, red oak sawdust used in the

present study.

XIII. Ignition Hazard Test for Liquid Oxidizers:

1.    Purpose of Test:

     To determine the relative fire hazard by exothermic reaction

of liquid inorganic oxidizers  with other substances or by

decomposition to products which ignite or sustain a fire.


Generally,  these  liquids react with nany organic substances and

some are capable  of producing spontaneous ignition when nixed

with the combustible at normal or slightly elevated temperatures;

some may also ignite spontaneously when heated in the absence

of a combustible  material.

2.   Operating Principle;

     In this proposed test, the ignitability or reactivity of

the oxidizer sawdust mixtures is determined in an open reaction

vessel using small quantities of the reactants.  Temperatures

up to at least 87.8C (190F) are used to compare the oxidizers,

depending upon their reactivity.  Such temperatures are not

necessarily unrealistic, considering particularly the possibility

of over-heating from the reaction of liquid oxidizers with

contaminants.  The reaction vessel in these experiments is a

200-cm^' Pyrex beaker that is equipped with insulated heating

tapes and which rested on a flat ceramic heater;  however, a stain-

less steel beaker can also be used.   Because of possible violent

reactions,  the reaction vessel is placed in a larger vessel of

heavy-duty steel  and the experiments are to be performed in a

prot ected area.

3 .   Test Description;

     In a trial,  a predetermined quantity of the sawdust (12 to

50 mesh)  is added to the reaction vessel and brought to the

desired temperature.  The liquid oxidizer is then cautiously

injected  with a  long hypodermic syringe ( 12 inches) fron behind

a  protective shield, and the extent  of reaction is determined

from continuous  temperature measurements and visual observations.


 The  mixture  temperature  is  measured with a 30-gage iron-

 constantan  thermocouple  protected  against corrosion by a thin-

 walled  glass  sheath  and  located  near the center of the reacting

 mass.   Ignitions  are  confirmed visually  since  the  flame reactions

 does not  necessarily  occur  in  the  immediate  area of the

 thermocouple;  in  many  ignitions, the sawdust-oxidizer  mixture

 is scattered  or the  flames  occurred primarily  near the top  or

 outside of the test vessel.  Generally,  evidence of ignition

 is observed  for periods  of  at  least 15 minutes.   If no significant

 temperature  increase  occurred, experiments  are  made at higher

 temperatures  and  with  various  sawdust-oxidizer  quantities.

 Preliminary  trials are always made  with  a small  quantity of

 oxidizer  1  ml), particularly in  the  case  of  an oxidizer of

 unknown reactivity.

 4.   Test Evaluation:

     This method  is not  applicable  to  detonable  liquid oxidizers,

 such as concentrated hydrogen'peroxide (90  percent)  or perchloric

 acid (72  percent).  A  shock sensitivity  or  thermal  stability test

 (Test XIV) is required for  evaluating  these  types.

 5.   Applicability of Test  as an Index of Waste  Oxldizing Strength

     (see Test XII, No.  5).

XIV.  Self-Heating Test for Organic  Peroxides*

 1.   Purpose  of Test;

     To determine the minimum ambient  temperatures  for  self-

heating to explosion of  thermally unstable compounds in  charges

of specified  shape but varying size.

2.   Operating Principle:

     The thermal decomposition of organic peroxides is observed

from studying temperature-tine plots to obtain the critical

temperatures for explosion, heat transfer coefficient data, and

apparent activation energies.

     A circulating fan located within the working space of the

furnace provides temperature control to within 0.5C.

3.   Test Description:

     A cylindrical tube furnace is constructed of steel housed and

an aluminum open-topped cylindrical container which could hold 40

to 60 grams of organic peroxide.  The furnace was heated elec-

trically over the range of 50C (122F) to 350C (662F) and

could be maintained at a fixed temperature to within 0.3C.

The progress of selfheating in the peroxide sample relative

to the furnace was observed by using a differential thermocouple

at the center of the sample.  A second thermocouple attached

to the side of the container monitored the surface temperature.

Temperature-time plots were recorded for different cylindrical

diameters for the samples and critical temperatures were


     Explosion studies were carried out with sample amounts

as large as 800 grams using a somewhat modified apparatus,

and similar parameters examined.

4 .   Test Evaluation:

     The chief disadvantage of the method is the long period

over which readings must be recorded and the long time required

for the furnace to stabilize following a large change in

operating temperature.


     5.   Applicability_of_T_est as an Index of Waste Oxidizing


          This test can be used to identify detonable oxidizers, but

     does not give any additional information other than that provided

     by the explosion temperature test.

D.    Tests for Identifying Water Reactivity3

     XV.  Test Method for Water Reactivity3

     1.   u..rJL ^ of Test:

          To identify materials which react so violently with

     water and provide a danger from ignition of nearby combustables,

     generation of flammable gases or generation of toxic fumes.

     2.   Operating Principle:

          Water reactivity of a substance is determined either

     by adding a given weight of water, to a given weight of material

     or vice versa.  In either  case,  the rate of temperature rise

     and the gross temperature  rise are recorded, and the gases

     evolved are sampled for analysis.

     3.    Test Description:

          The sample container  is a Pyrex tube,  1-3/8 inches in

     diameter by 10 inches  long, imbedded to a depth of 3-1/2

     inches in a block of insulating  foam (polyurethane or poly-

     styrene) 3 inches square by 5 inches high.  A thin piece of

     copper 3/8 inch square  and weighing 0.5 gram (about 0.025

     inch  thick)  is silver-soldered to the tip of a chromel-

     al.umel thermocouple which  measures the temperature rise.  This
       Test  XV  is  taken from "Classification of Hazards of Materials--
       Wat er-React ive  Materials  and Organic Peroxides", C. Mason and
       J.  C.  Cooper, NTIS  Number PB-209  422.


thermocouple  is placed in the Pyrex tube in such a way that the

copper square is near enough to the bottom to be covered by

the sample.   The output of the thermocouple is fed to a

suitable recorder.

     An initial estimate of the severity of the reaction is

made by adding 5 grams of water slowly to 0.5 gram of material

with, the apparatus behind a protective shield.  Since either

toxic or flammable gases may be evolved, the test must be

carried put in a suitable fume hood.  The temperature rise

is measured by adding 10 grams of water slowly (10-20 sec) from

behind a protective shield to 1, 2, 5, 10, and 20 grams,

successively, of the sample.   Measurements are continued

until the temperature reaches a peak and then begins to drop.

If 1,  2, and 5 grams of the material give virtually no temper-

ature increase in 4 minutes,  10 grams of water are added to

10 grams of sample and the temperature is monitored for 1

hour to determine whether a slow reaction occurs.  If the

reaction is not too violent,  10 grams of water are added

to 20 grams of the material to see whether a greater rise in

temperature results.  The procedure may be reversed by adding

the material to the water in the container.  The best method

to determine whether a flammable or toxic gas is evolved is

by chemical analysis of the gas.  If a gas is evolved, a

sample from the reacting material is collected through a.

flexible needle inserted into .the reaction container to with-

in about an inch of the reacting mixture.  The.sample is then

analyzed on a. chromatograph for flammable and/or toxic gas.


 4.    Test

      The test  is  reproducible  to within  10 percent.   The  test

 results for  known  reactives  like the hydules  of  the alkali

 metals are positive.   There  seems  to be  little difference in

 the results  caused by  the order of mixing.

 5.    Applicability of  Test as  an Index of Waste  Reactivity:

      A test  such as this could be used to identify pyrophoric

 wastes, wastes which generate  toxic gases when contacted  with water


      The test method appears to define the activity of  the

 various materials  tested.  Classification of  the water  reactivity

 hazard could be based  on the temperature rise which is  a

 measure of the heat released by reaction with water.  The

 release of flammable and/or  toxic gases would create  an

 additional hazard which could be covered by a classification

 such  as the  following:

                           t ive Wastes:
          Wastes which react with water to give

          temperature rises of 60C (140F) a_nd_

          evolve toxic or flammable gases.

          Wastes which react with water to give

          temperature rises greater than 60C (140F)

          or evolve toxic or flammable gases.

     Simplified methods of analysis for toxic gas, (particu-

larly HCN and H2S) must be developed before this test could

be considered.


                         APPENDIX IV
     The information contained in this Appendix was extracted

from "Evaluation of Solid Waste Extraction Procedures and

Various Hazard Identification Tests (Final Report)", NUS

Corporation, September 1979.

  1.    Reactivityt Explosion Temperature Test Testing Method

       The Explosion Temperature Test, which is described in

  Attachment A to this Appendix, was used by two independent.

  laboratories (Safety Consulting Engineers, Inc. of Rosemont,

  Illinois and United States Testing Cotapany, lac.) to determine

  reactivity.  The purpose of this test is to determine the

  temperature at which a material explodes, ignites, or deconposes

  in a  Wood's metal bath after being immersed for five minutes.

 Table IV-I gives the testing results obtained from the Explosion

 Temperature Test.
 2.    Conclusions and Recommendations of the Explosion

      Temperature test

      The proposed Explosion Temperature Test is unacceptable

 on  the basis of the testing results.  Interpretation of the

 testing results is too subjective.

      As a replacement for the Explosion Temperature test, it

 is  recommended that differential temperature methods be

 considered.   For example, differential .scanning calorimeter

 testing (i.e., differential temperature analysis)  is a quick

 and accurate means for objectively  determining  the temperature

 at  which a material will  decompose  or react with other materials

'This  system  is composed of  a  sensitive array of temperature

 sensors,  an  adiabatic chamber,  several small heating elements,

 and  a  data processing and recording system.

     To determine  the amount  of  energy absorbed or given up

 by  a substance,  a  0.1 to  5.0  mg  sample is  placed into the


                          TABLE  IV-I


Ferromanganese Dust

Ammonium Nitrate



    Testing Results

5 min.  at 350C,  no  reaction

207C,  slignt reaction

Between 300C and 325eC,
major reaction (sample de-
composed,  smoke visible)

 210C, major reaction

 adiabatic chamber and the temperature Is increased via the

 heating elements.  The data are recorded on a strip chart.

      This is a very sensitive method.  It can detect changes

 such as loss of water of  hydraticn,  phase changes,  etc.

 It will give indications  of innocuous events as  well as  severe

 ones.   Endo- or exothermic  reactions are clearly indicated

 by changes  in the recorded  temperature curves.

 3.    Supplemental General Comments  (These comaents  are those

      provided by  the  two  laboratories participating in the

      testing program)

 1)   Wood's  metal  is  composed  of bismuth (50.09%),  lead  (25%),

     tin  (12.5%),  and  cadmium  (12.5%).   The  use  of  a  molten

     metal bath could  re'sult  in potential OSHA violations

     because  of the toxic nature of  the  metal fumes.

 2)   The  proposed  method  is archaic  and  the  results  are  highly

     subjective rather than objective.   The  nethod  is  time

     consuming.  A thermal  analysis  (i.e., differential  tem-

     perature analysis) is  rapidly performed and the  thermal

     properties are easily  identified.   Testing  results  are

     reproducible and many  commercial laboratories  provide

     these analytical services at reasonable fees.

3)   Determining if a reaction has taken  place by visual

     observations is very subjective.  One laboratory  sealed

     the copper tubes with vise-grip pliers and immersed the

     tubes in the bath.  A reaction was judged to have taken


place If bubbles were observed in the molten bath.  The

test procedure gives no standard nethod for sealing the

tubes to prevent molten metal for contacting the sample,

and determining if a reaction has taken place is the

opinion of the analyst.

                          Attachment A
                     (March 17, 1978 Draft)
 1.   Purpose of Test

      To determine the temperature at which material explodes,

      ignites, or decomposes after a five minute immersion in

      a Wood's metal bath.

 2.   Operating Principle

      This test gives an estimate of how close the explosion

      temperature is to ambient conditions for a material, and

      hence,  provides a measurable indication of theraal insta-


 3.   Test Description

      The  material to be tested (25  mg.)  is placed ia  a  copper

      test tube (high thermal  conductivity) and  immersed in a

      Woodf's metal bath.   This test  is made at a series  of bath

      temperatures ,  and the  tine  lag  prior to explosion  at each

      temperature is  recorded.  The  bath  temperature is  lowered

      until a.  temperature  is reached  at  which explosion,  ignition,

      or apparent decomposition does  not  occur.   The bath temp-

      erature  working  range  is  from  about  125 to  400'C.   Tbe

      sample is removed  from the  bath after 5 ninutes  if  no

      explosion has occured  at  360C.

Taken from "A  Second  Appraisal of Methods  for Estimating Self
Reaction Hazards," E.S. Domalski, Report  No.  DOT/MTB/OHMO-76/6.
Department of Transportation.