United States
            Environmental Protection
            Office of
            Solid Waste &
            Emergency Response
June 1984
           Solid Waste
Assessing the Releases and
Costs Associated with Truck
Transport of Hazardous Wastes
           Executive Summary

     This report was prepared by Dr.  Mark Abkowitz  and Dr.  Amir  Eiger,  Faculty
Members, Department of Civil Engineering,  Rensselaer Polytechnic Institute,  Troy,
N.Y., and Mr. Suresh Srinivasan of Transportation Consultants, for the  U.S.
Environmental Protection Agency and IGF Incorporated under  contract.

     The report has been reviewed by the U.S.  Environmental Protection  Agency (EPA)
and approved for publication.  Its publication does not signify  that  the  contents
necessarily reflect the views and policies of  the U.S. EPA, nor  does  mention of
commercial products constitute endorsement or  recommendation for use  by the  U.S.


        This report was prepared for
      the Office of Solid Waste under
          contract no.  68-01-6621

              Washington,  D.C.

     This report presents an analysis which estimates the releases
from and costs of transporting hazardous wastes.   These estimates will
be included in a larger, more general analysis of hazardous waste manage-
ment, namely, the Office of Solid Waste "RCRA Risk-Cost Analysis Model."
The complete report on the transportation analysis will be available
from the National Technical Information Service (NTIS), Springfield,
Virginia 22161.  Single copies of the Executive Summary (including the
Table of Contents to the entire report) are available directly from EPA.

                       TABLE OF  CONTENTS




     Fraction Release Analysis Methodology	3

        Data Description	4
        Estimating the Truck Accident  Rate	6
        Incident  Modeling	7
        Estimating the Expected  Amount Released	9

     Estimating  the  Cost  of Transporting Waste	   10

        Trip Profile Analysis	   10
        Cost Methodology	   12

     Model Application	   14

        Release Computation	   14
        Cost Analysis	   15

     Concluding  Remarks	   15




     3.1 Truck Accident  and Volume  Data	   25

        3.1.1 Texas	   26
        3.1.2 California	   26
        3.1.3 New  Jersey	   26

     3.2 Hazardous  Waste Shipment Information	   28

        3.2.1 California	   29
        3.2.2 Texas	   31
        3.2.3 Massachusetts	   31
        3.2.4 New  York	   34


      The  authors  would like  to  acknowledge the advice,  guidance and

cooperation  of  Curtis  Haymore,  Arline  Sheehan  and Eric Males of the

Office  of  Solid  Waste,  U.S.  Environmental  Protection  Agency.   The

assistance  provided by  Joseph  Kirk,  Leslie  Kostrich,  Stephen  Bailey

and  Jean  Tilly  of  ICF  Incorporated  is  also  sincerely  appreciated.

Finally,  substantial and  useful  comments during  the  review  process

were  made  by  Russell  Cappelle  of American  Trucking Associations,

Inc.,  Joseph  Nalevanko  of the  U.S.  Department of  Transporation's

Materials Transportation  Bureau  and John  Thompson  of  the  Office  of

Solid Waste,  U.S.  Environmental  Protection  Agency.

      3.3 Hazardous  Waste Incident  Data	   34


      4.1  Data  Refinement	   40

      4.2 Analysis  Results	   42

          4.2.1  California	   42
          4.2.2  Texas	   45
          4.2.3  Massachusetts	   48
          4.2.4  New  York	   51

      4.3  Implications of  Pooling  State Data	   54

      4.4  Summary	   56


      5.1  Container  Classification	   59

      5.2  Incident Occurrence Model	   61

      5.3  Estimating the Mean Shipment Distance	   65

      5.4  Fraction Release Model	   67

      5.5  Fraction Release Estimators	   76

     5.6  Fraction Release Estimates	   77

     5.7  Errors  of the Estimates	   79

     5.8  Results and  Implications	   81


     6.1  Analysis	   84


     6.2 Results  and Implications	   86


     7.1 Literature Review	   93

     7.2 Revised Procedure	104

        7.2.1  Average Cost  Approach - 6,000  Gallon Tanker. .  .   106
        7.2.2  Average Cost  Approcah - 18 Ton Stake Truck  .  .   107
        7.2.3  Deriving Cost Formulas	108

     7.3 Comparison with  Actual Charges	109

     7.4 Summary	Ill


     8.1 Scenario 1	112

        8.1.1  Release Computation	112
        8.1.2  Cost  Analysis	114

     8.2 Scenario 2	115

        8.2.1  Release Computation	115
        8.2.2  Cost  Analysis	116

     8.3 Concluding Remarks	116


     CODES   	132

                        EXECUTIVE SUMMARY

      In   response  to  a  growing  concern  over  the  management  of

hazardous wastes  and their  impact  on  the population  and environment,

the Resource  Conservation and  Recovery  Act  (RCRA)  was enacted  in

1976.    RCRA  authorized  the  EPA to  establish  a  hazardous  waste

control  program  for the  nation,  which  includes the  identification  and

classification   of   hazardous  wastes,   requirements   for  owners  and

operators   of   hazardous  waste  facilities,  and  guidelines  for  state

programs  developed  under the act.

      In  1981, as part  of the  national hazards waste control  program,

EPA's  Office  of  Solid  Waste  began  to  develop  its  RCRA  Risk/Cost

Analysis  Model.   The model  is  designed  to assist  in the development

of hazardous  waste  policies.

      The  RCRA  Risk/Cost  Analysis  Model  consists of  an  array  of

possible ways to  treat,  transport  and  dispose  of the  hazardous  wastes

generated  in  the  United  States.   There   are  three  main  factors

considered in  the  model's  formulation  of  possible  ways  to  manage

hazardous waste:

        (1)   The   type   of  waste   (and   its   hazardous   chemical


        (2)   The  types  of technologies  used  to  treat,  transport  and

             dispose of  the  wastes.

        (3)   The  environmental  settings   in   which   the  wastes  are

             treated, transported  and  disposed.

       The  model forms  ail  possible  combinations  of  a  list of wastes,

 technologies and environmental settings  --  or W-E-T cells.  The model

 then calculates  the  risks  and  costs  involved in each W-E-T  cell.   In

 this  fashion,  the relative merits  and drawbacks of  various  hazardous

 waste management strategies  can  be  identified.

       This  report focuses on one component of the RCRA  Risk/Cost

 Analysis  Model:  the  costs   incurred and  expected  fraction  released

 (R  ) during  transport  of hazardous wastes.   The objectives  of our

 project were  governed by the following  criteria:

          In  order to establish a  tool for  policy analysis, we  wanted

          to estimate  a  fraction release  model that  reflected,  as  much

          as  possible,  actual  data on hazardous  waste  shipments  and

          incidents.      Compiling    a   comprehensive   data   sample

          necessitated  extensive  data collection  at  both  the  state  and

          federal levels.

         In order to  ascertain whether  previous  studies  were  reliable

          for  policy   analysis,  we  performed   a   critical  review  of

          existing truck transport cost  studies.    We then  developed

          revised cost formulas to  account  for deficiencies  identified  in

          the  review  process  and  compared  the  revised  cost  procedure

          with quoted  rates  to validate its  applicability.

Because  90  percent  of  all current  hazardous waste transport  is  via

truck, the  transport   release  model and cost  review were  restricted  to

truck transport.1
      authors are presently conducting studies of the release rates
and  costs  of  hazardous waste  shipments by  rail and  waterborne

  Fraction  Release Analysis Methodology

       Hazardous waste  releases  during  transport  can  result  from  a

  number  of causes  (failures modes) and  can occur either  at shipping

  terminal points  or  en route.   We  defined  three incident  types:

         (1)  Container failures due to vehicular  accidents enroute.

         (2)  Container failures occurring  enroute  due  to causes  other

              than vehicular  accidents.

         (3)  Container failures at shipment  terminal points.

 We  formulated   a  Transport Release  Model  to   compute  the expected

 fraction  released (Rt_)  during transport.   This  is a  function  of:  (1)

 the expected  fraction released enroute  and  (2)  the expected fraction

 released  at terminal  points.   Deriving these  release fractions requires

 an understanding of the  expected  fraction  released given  an incident

 for  each failure mode, the  probability of  an incident   for each failure

 mode  and,   for enroute  incidents,  the   distance shipped.   It  is

 necessary  to  estimate these parameters  for each  container  type  used

 in  transport.   Thus,  the total  number of  parameters   to be estimated

 depends   on   the  number  of   container   types  and   failure  modes.

 Furthermore,   the  use  of  the   model  for  policy  analysis  requires

 hazardous waste shipment  distances  as input.

      Estimating  incident  probabilities  also  requires a determination  of

the  total  involvement.    For example,  total  involvement  for incidents

which occur enroute is a function of the total  distance  shipped  (i.e.,

the   average   shipment   distance   multiplied    by  the   number   of

shipments).   For incidents  which  occur  at  terminal points,  the  total

involvement is the total  number of shipments.   Thus,  it is  necessary

to  estimate   the   average   shipping  distance  and   the  number  of

shipments for each container type.

      We  computed  these   measures  using:  (1)  shipping  distances

derived  from  incident  data,  2)  data   on  the  number  of  vehicular

accidents  and 3) independently  derived  estimates  of vehicular accident

rates.   Subsequently,  it became possible to compute  incident rates for

other failure  modes.    It was not  necessary to  perform  this explicitly

for each  container type.   Rather,  we expressed  all  incident rates in

terms  of  a  common   vehicle  accident  rate.   We  assumed  that   this

accident  rate  does   not   depend  'on   the  container  type  used  for


Data Description

      We  identified  three  types  of  data   which  were  necessary  to

conduct the release and cost analyses:

        (1)  Truck accident and volume  data.

        (2)  Hazardous waste  shipment information.

        (3)  Hazardous waste  incident data.

Wherever  possible,  we  obtained  data   from  1980,   1981   and  1982,

because   they  represent   the   most  recent  information  available  on

hazardous waste incidents  and  shipments.

      We  obtained   truck   accident  and   volume  data  from   Texas,

California  and  New  Jersey  records.    Each  record   included  average

daily  counts of vehicular traffic characterized by vehicle type  and the

annual  number  of  truck  accidents.   The   California  and  Texas   data

included  observations  for  interstate  highways,   U.S.   highways  and

state  routes.    The  New  Jersey  data,  on  the  other  hand,  included

 many  highway  sections containing intersections with traffic  signals.

       We collected data on  hazardous  waste shipments  from  California,

 Texas,  Massachusetts  and  New  York  manifest records.    In  general,

 each  record  contained  the  following   information:   origin   location,

 destination  location,   waste  type  transported,  quantity  shipped  and

 unit  of  shipment.  A  significant problem  with this database was its

 lack  of  accuracy  in  reporting  the locations of generation and disposal

 sites.    In  some  cases, the county  of  origin  or  the  destination  state

 was the  only  location  description.   Thus,  it was necessary to make

 some assumptions  to  correct for this. problem.  State data  also did  not

 consistently include  interstate shipments.

       The  primary data source  for estimating  the incident   probability

 and fraction  release  parameters  was  the  Hazardous  Material  Incident

 File (HAZMAT)  maintained  by  the U.S.  Department  of  Transportation's

 Materials   Transportation  Bureau  (MTB).    HAZMAT,   a  compilation  of

 nationwide  data  on hazardous material   spills,  contains information on

 the  frequency  and circumstances  (container involvement,  failure mode,

 severity  of  resulting  spills,  etc.)  surrounding  hazardous  material


      Although   over  8,000  incidents   of  hazardous   material   spills

 involving  truck  travel  were reported  in   1981, a closer  inspection  of

these  data indicated  that  an extremely small number (84)  of  these

spills  involved   hazardous   wastes.     Because   the   sample  size  of

hazardous   waste  incidents  was   not   large   enough   for   statistical

analysis,  we  considered  all  of  these hazardous  materials  incidents  in

developing  the  incident model.    Also,  because we postulated that the

incident  rate and fraction  release  models   do  not  depend on the type

 of waste  being shipped, but  rather, on  the container type  used, and

 because the HAZMAT file covers a  wide  range of container types, this

 approach  is justified.

 Estimating the Truck Accident Rate

      We  assumed  that  the truck  accident rate  is  a function of  the

 highway  type  and  traffic  conditions.   Truck  accident and volume data

 were obtained  from  California,  Texas  and  New Jersey;  these  data

 represented  a  wide  range  of  traffic  and  truck  volumes  and  four

 different  highway  types.   To test the  statistical significance of any

 differences   in  accident  rates   under  different  highway  and  traffic

 conditions,   we conducted  an analysis  of variance  (ANOVA),   which

 indicated  the significance of the traffic  volume,  truck percentages and

 highway type.

      The  analysis of  the  accident  rate  data   yielded  the  following

 estimate for aggregate  accident  involvement rates (releasing  accidents

 per  million  truck  miles):

 Interstates                    0.13

 U.S.  and State Highways     0.45

 Urban                        0.73

Composite                     0.28

      These  results  fall  within  the  range   of  previously   reported

estimates  and   demonstrate  the  difference  in   the  accident  rate  for

various  highway types.   The truck accident rate is  also  dependent  on

both  the  total traffic  volume  and the  percentage  of  trucks  in  the

 traffic stream.   These  results suggest that in applying  the estimates

 provided,  cell means should  be  used  in  lieu  of aggregate means  if

 sufficient information  is available to identify the highway  type and the

 traffic volume.

 Incident  Modeling

       The  HAZMAT   file   of  reported  hazardous  materials  incidents

 allows the  coding of  up to  334  container  types and 27 failure  modes.

 From  our analyses of these data,  we identified 8 container  types with

 reasonably  uniform  physical  characteristics  and  incident  involvement


        (1)  Cylinders

        (2)  Cans

        (3)  Glass

        (4)  Plastic

        (5)  Fiber Boxes

        (6)  Tanks

        (7)  Metal Drums/Pails

        (8)  Open Metal  Containers

       For   each  of   these  container   classes,   we   determined  the

 respective  parameters  in  the   fraction   release  model.    Table  1

 summarizes   the  resulting   estimates   of   the  fraction   released   by

 container  type.

      The  results of our   analyses  indicate  that  in  terms of  their

order  of  magnitude,  the expected  fractions  released  per  mile shipped

               -8        -6
 range  from  10   to  10  ,   depending  on  the  container  class.    The

expected  fractions   released  at  terminal  points  range  from  10    to

10  ,  depending on the  container  class.

 Table 1   Estimates of Fraction Released by Container Class
Expected Fraction
  Released Per
  Mile Shipped**
Expected Fraction
Released at Terminal







1.3 x 10~6 + (.13 X1)

2.6 x 10~6 +(.12 A')

1.7 x 10"6 +(.27 A')

4.1 x 10"6 +(.14 A')

1.3 x 10"6 +(.12 A')

4.2 x 10"8 +(.19 A')

2.4 x 10~6 +(.10 A')

7.5 x 1(T6
 1.4 x 10
 4.0 x 10
 2.6 x 10
 5.2 x 10
 6.1 x 10
 7.6 x 10
 2.9 x 10
                                                          1.2 x 10
*astimate  associated with the  release fraction during  accident  is  not
**A'  = releasing vehicle accident rate.

      Our  computed estimates indicate that:

        (1)  The  release  rates  for  tank  trucks  are much lower  than

             for  other container types.

        (2)  The  expected amount  released at terminal points  is  one to

             three  orders   of  magnitude  higher   than  the  amount

             released  en route.

        (3)  The  expected   release  fractions   during   transport   are

             potentially  as  high  as the  release  fractions  at disposal

             sites and treatment facilities,  which  range  from 10"   to

               -3                             -5       -3
             10   for routine spillage  and  10    to  10   for  accidental


Estimating  the Expected Amount Released

      Using  the  model parameters  given  in the  previous  sections, we

employed  the  following  procedure  to  estimate  the  expected fraction

released  during transport:

        (1)  Identify  shipment  characteristics.

               -  number  of  shipments

               -  volume per  shipment

               -  trip  distance

               -  container type

        (2)  Identify  highway characteristics.

               -  highway  type

               -  traffic  volumes

        (3)  Select  appropriate  values  of fraction   release  parameters

             for the container type being considered.

        (4)  Compute  the fraction  of  accidents  that involve releases

              (derived as the truck accident rate multiplied by 0.2).

         (5)   Determine  fraction   released   en route  and   at  terminal


         (6)   Multiply  fraction  released enroute  by total  trip  miles and

              fraction  released  at terminal  points  by  the  number  of


         (7)   Add  these  values  to  arrive  at total  expected  fraction


         (8)   Multiply  this  by  the  total  volume  to  obtain  the  total

              expected amount  released.

 This  procedure  is demonstrated  in  the discussion  on  model application.

 Estimating the Cost  of Transporting Waste

 Trip  Profile Analysis

      Using   the   waste   shipment   data  from   Texas,   California,

 Massachusetts and New York,  we examined the following:

         (1)  The mean shipping  distance,  segmented  by  waste  type

              (for each state).

         (2)  The  quantity   shipped,   segmented   by  waste  type  (for

             each state).

         (3)  The extent  to which   the  above  measures  vary  across


The resulting  information was  used  in  cost  applications where specific

trip lengths  and the quantities shipped  were  not  known.

      In order to determine if the quantity  and/or distance shipped  is

related   to  the  waste type (solid  or  liquid)  or  the  particular  state

under  consideration,  we  conducted  a  multivariate  analysis of  variance.

 The results  of the analysis indicated  that  the  shipment characteristics

 of  liquid  and  solid wastes  vary  by state  and  consequently  we  could

 not  derive  aggregate  estimates.    This  resulted  in  our conducting

 separate analyses for each  state.

       Our  analysis results  indicated that  trip  distance  and  quantity

 shipped  vary  by  waste category  and  also vary  considerably  among

 states.   This  is  likely due  to  differences  in  the  manifest system,

 geographic location,  size and  industrial activity of each state.

       We  did,   however,  conclude   that  the quantity  transported  is

 independent  of  trip  distance.   Our findings do  not  substantiate  the

 argument  that  shipments  are  filled  closer to capacity on  longer  trips

 than shorter ones.   We also  found  that  in  three of the  four  states,

 the   mean   shipment   size  for   liquids  is  larger  than  for  solids

 shipments,  and that  in  three of  the  four  states,  the  average  trip

 distance is longer for solids shipments than  for liquids  shipments.

      Questions  are sometimes raised regarding  general  waste  shipment

 characteristics  for  the United  States.   Although  there  is  no  basis  for

 assuming that  our  sample   is  typical  of  the  entire  hazardous  waste

 transport  industry,  we computed weighted  averages of  the  shipping

 distances and quantities which  reflect  the number of annual  manifests

 in  each  of  the  states.    These  weighted  averages   should not  be

 misinterpreted to apply  to specific hazardous waste  transport  scenarios

 in the United States.

      The  mean trip  length for  all shipments  is 84.2  miles,  with a

mean trip  length   for  liquids  of  77.1  miles  and  for  solids  of   109.6

miles.   For liquids,  the mean  quantity shipped  is  3,171  gallons.    For

solids,  it  is  2,791  gallons   (11.6  tons).   The  trip  distance  frequency

distribution for all four  states, for both  liquids and  solids, follows  an

exponential  distribution.   This  is not  surprising  because disposal  sites

are likely to be  located  near  points of waste generation.

Cost Methodology

      We  reviewed the existing  literature on the  cost  of  transporting

hazardous  waste  and  identified seven  studies which  treated the  issue

of estimating the cost  of transporting  hazardous  waste   by  truck.   All

seven  studies  considered this  issue within the  larger framework of  the

total cost and  risk  of  hazardous waste treatment at a regional  level.

      The  studies' results varied from  gross estimates of the  unit cost

of transport to more sophisticated  derivations of costs   based  on  fixed

and  variable  components.    We  noted   several  deficiencies  in  these

methods,   particularly   in   the   assumptions   relating  to  shipment

characteristics   (for example,   all  of the  studies  assumed  that  vehicles

travel  at capacity,  which is  not substantiated  by the  results  of  the

trip  profile  analysis)   and their failure to compare their results to  the

actual  rates  charged by   haulers.

      Using    the   most   comprehensive   of  the   methodologies,   we

developed   a  revised   costing   procedure   which   was   designed   to

overcome these   deficiencies.    Our modifications  included considering

trip  distances  and  shipment  sizes  based on  the  trip  profile  analysis

results,   using   1983  component  costs,   and   comparing  the  revised

methodology to actual  price quotes from  waste  haulers.

      We  then   used    the   revised   costing   procedure   to   estimate

transport  costs   for 6,000  gallon  tankers   and  18-ton  stake   (flatbed)

trucks.    The   average  costs   computed   using  the   trip   profile

characteristics are:

                         Tankers                 Stake Trucks

Average Cost  Per        $4.14                    $4.55

Loaded Mile  ($)

Average Cost  Per        $0.31                    SO.39

Loaded Ton-Mile ($)
The average  costs  per loaded  mile and loaded ton-mile are larger for

stake  trucks  than  tankers.    This  is  due  to  the  smaller  loads

associated  with  stake trucks.

      In  order  to  estimate  the  cost .of  transport  when   details  on

specific  shipments are available,  we derived the  following  formulas for

tankers  and  stake trucks:
      elm.   .    ($/loaded mile)  = 3.08 *
                                       3.08   88.8
      cltm.   ,    ($/loaded ton -mile)  = - *
      clmstake ($/loaded mile)  = 3-02
                                      3.02    129.38
      cltm  ,  .   ($/loaded  ton-mile)  =  	 *
                                       Y       XY


          elm = cost per  loaded  mile

          cltm  = cost per loaded ton-mile

          X  =  shipment distance (miles)

          Y  =  shipment size (tons)

      To determine the accuracy of the revised costing procedure,  we

 compared its  estimates with the actual  rates  charged by  haulers.   The

 comparison  showed  that  the  estimates  we  obtained  using  this  cost

 formula  appear  to  be quite  representative  of  quoted   rates  in  the

 hazardous   waste  transport   industry.    The   average  cost  figures,

 however,  did  not  compare  quite as  favorably.   Consequently,  we

 recommend  that  the  average  cost  figures  should  be  used   rather

 carefully,   and  should  only  be  employed  when  information  js  not

 available on trip distance and/or  shipment size.

 Model Application

      To  illustrate  the established release  and  cost  procedures,  we

 posed the  following problem:

 Suppose 200  55-gallon  drums are  being  shipped  a  distance  of  TOO

 miles  on  interstate  highways.   The  average  daily  traffic  (ADT) and

 truck  percentages  on  the  highways  are  unknown.   What  are  the

 expected releases and  cost involved?

 Release  Computation

      From  previously  reported  results,  we  obtained   the  releasing

 accident rate for  interstates  as  0.13  x  10     releasing   accidents  per

truck mile.   The expected amount released enroute was obtained  using

the fraction released from  Table 1 as:
E  (release enroute) =  (2.4x10~6  *  0.10x0.13x10~6) x  100  x  200 x 55

                      = 2.65 gallons

 E  (release at  terminals) = 2.9x10~4  x  200 x 55

                         = 3.19 gallons

 Total  expected release  = 5.84 gallons
 Cost Analysis

       The  average  load  carried  by  stake  trucks  is  2,791   gallons,

 which  is  equivalent  to  11.6  tons.    The  quantity  being   shipped  is

 11,000 gallons,  which   is  equivalent  to 45.83  tons.   The cost  per

 loaded ton-mile is:

                                     3.02      129.38
      cltm .  .   ($/loaded ton-mile)  =  	 +  	 = 0.37
         staKe                       11.6   (100M11.6)

      Number  of ton-miles per shipment = 11.6 x 100  =  1160

      Cost  per shipment  =  1160  x  0.37 = $429.20

      Average number of shipments =  3.94

      Total  Cost = 3.94  x 429.20 = $1,691.05
Concluding  Remarks

      This  project  has  addressed the  potential  releases and  costs of

transporting hazardous  wastes by truck.   In the course of  conducting

this  study,  we drew  several  conclusions  that are  useful  for policy

analysis.   Below, we briefly  discuss our  conclusions.

      A  trip   profile  analysis  conducted  on  data  from several  states

indicated  that, on  average,  wastes  are  shipped  less  than  TOO  miles

from their generation  to their  disposal  sites.   The average trip  length

is  lower for  liquids than  for  solids.  Generally  speaking,  the  mean

quantity shipped  is independent of shipping distance.

      In  assessing  truck  transport   releases,    it  is  important  to

distinguish  between two kinds  of  incidents  that result in  spills.  For

one class  of incidents,  the probability of occurrence  is  a function of

the distance traveled;   for  the  other, the occurrence  probability for a

particular  shipment is   fixed.    We  computed  expected  fraction  release

estimates  for  both kinds of incidents.

      The  costs  of transporting   hazardous  wastes  by truck  can  be

reasonably  approximated  using  the  formulas  derived  in  this   study.

These  cost  formulas compare well  with  actual industry  quotes.

      The  individual  and  collective results  of the  entire  analysis are

applicable  at  many  levels  of  aggregation.   Using  this  study's  models

and  cost  formulas,  it is possible  to obtain  broad  estimates of expected

releases and transport  costs,  as well  as  estimates  of  the  releases and

costs  involved in  individual shipments.

      Perhaps  the  most important result of  this  study  is  that the

release  rates   associated with  transporting  hazardous  wastes  by  truck

appear  to  be  as  large  as  the  potential   releases  at  treatment and

disposal  sites.    In fact,  for some W-E-T combinations,  transport may

be  a  potentially  more   dangerous   activity.   As  a  result,  policymakers

should  give careful  consideration  to  the relative  risks  involved  in  the

treatment, transport and  disposal  of  hazardous  wastes.