22204
         2-(2,4,5-trichlorophenoxy)  Propionic  Acid  (Silvex)

              Notice  of  Intent  to  Cancel  Certain  Registra-
              tions  of Pesticide Products  Containing  Silvex

       I.   INTRODUCTION

           I  am  today issuing  an emergency order  suspending

       immediately  the forestry, rightsrof-way, pasture,  commercial/

       ornamental turf,  home and garden,  and aquatic  weed control/

       ditch  bank uses of  pesticide  products containing  silvex,  and

       a  statement  of reasons.  Sect ion. 6(c)(1) of  the Federal

       Insecticide,  Fungicide  and  Rodenticide Act (FIFRA) [7 U.S.C.

       Section 136d(c)(D]  provides  that  a suspension order cannot

       be  issued unless  a  notice of  intent  to cancel  the  registra-

       tions  or  change the  classifications  of the pesticide products

       concerned has  already been  issued or is issued with the

       suspension order.   For  the  reasons  set  forth below, I find

       that  forestry, rights-of-way, pasture, commercial/ornamental

       turf, home and garden,  and  aquatic  weed control/ditch bank

       uses of pesticide products  containing silvex,  in  accordance

       with current use  instructions, appear to pose  an  unreasonable

       risk to humans.   I  am therefore announcing my  intention, to

       cancel all these  registered uses of  silvex under  Section  6(b)

       of FIFRA  [7 U.S.C,  Section  136(d)(b)].

           LEGAL AUTHORITY

           Section 6(b)  of FIFRA  [7 U.S.C. Section 136d(b)]

         horizes the Administrator to issue a notice of intent

         cancel the  registration  of a pesticide or to change

         t classification  if it appears to him that the pesticide

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or its labeling "does not comply with  the provisions of


IFIFRA] or, when used in accordance with widespread and


commonly recognized practice, generally causes unreason-


able adverse effects on the  environment."  Thus, the

      /

Administrator may cancel the  registration of  a pesticide


whenever he determines  that  it  no  longer satisfies the


statutory  standard  for  registration which requires (among


other things) that  the  pesticide  "perform its  intended


function without unreasonable adverse  effects  on the


environment" [FIFRA Section  3(c)(5);  7 U . S .C .  Section


136a(c)(5)3.  He may also change  the  classification  of  any


use of a pesticide  if he determines that such a  change  "is


necessary  to prevent unreasonable  adverse effects  on  the


environment" [FIFRA Section  3(c)(2);  7 U.S.C.  Section


136a(d)(2)].  "Unreasonable  adverse effects  on the


environment" means "any unreasonable  risk to  man  or  the


environment, taking into account  the  economic,  social  and


environmental costs and benefits  of the use  of any pesticide"


IFIFRA Section 2(bb); 7 U.S.C.  Section 136(bb)].


     The burden  of  proof  for establishing the safety  of a


pesticide  product  to support a  decision  concerning


registration or  continued registration rests  at  all  times


on  the proponent of  registration  [Environmental Defense


Fund  v.  Environmental _g.rjp_te.ct i on  Agency, 465  F.2d  528,  532


(D.C.  Cir. 1972);  EOF v. EPA, 510  F.2d 1293,  1297  (D.C.  Cir.
                         % -

1975); EOF v. EPA,  548  F.2d  998,  1004  (D.C.  Cir. 1976)].
                  i

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     In effect, FIFRA requires  the Administrator to weigh




the risks and benefits  associated  with each use of a pesticide.




If he determines  for any  particular use that the risks




exceed the benefits, he must  then  determine whether those




risks can be sufficiently reduced  (so that they are outweighed




by the benefits)  by  the imposition of restrictions upon use




through changes in  the  labeling  and/or by the classification




of the use for restricted use.   If he determines that




ade/jate risk reduction  cannot be achieved by such regulatory




measures, the  registration of the  pesticide for that use




must be fully  cancelled.




III.  REASONS  FOR INITIATING  PROCEEDINGS TO CANCEL




     A.  Risks




       On the  basis of  data available to the Agency, I




conclude that  silvex and/or its contaminant, 2,3,7,8-




tetrachlorodibenzo-p-dioxin (TCDD), create a serious health




risk  for humans  and that  human exposure to silvex and/or  its




contaminant, TCDD,  is  cause for considerable concern.




       The Agency has  reviewed numerous studies in which




industrial,  academic,  and government  scientists have reported




that TCDD and/or  silvex contaminated with TCDD produce




fetotoxic, teratogenic, and carcinogenic effects  in test.




animals that have been  exposed to  these chemicals.  The




occurrence of  these adverse effects in test animals following




exposure to  silvex  and/or TCDD indicates that humans who




are  exposed  to silvex may experience comparable effects.




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Concern  for  the  health of humans who may be exposed to TCDD,

and therefore  silvex contaminated with TCDD is heightened

because  scientists  have not demonstrated that there is a

level  of  exposure  that has no adverse effects in humans.—

       A  recent  EPA-sponsored epidemiological study shows

human  miscarriages  to be related both geographically and

temporally  to  the  use of 2,4,5-T (a chlorophenoxy herbicide

closely  related  to  silvex, and which also contains TCDD).

Specifically,  the  study indicates that women who live in an

Oregon area  (Study  area) where 2,4,5-T is used for forest

management  experience miscarriages more frequently than do

women  who live in  other Oregon areas where there is little

or no  known  use  of  2,4,5-T or other dioxin-containing

phenoxy herbicides.   Most significantly, the data generated

through  this study  show that the increase in frequency of

miscarriages for women in the Study area is greatest two

months after the period when 2,4,5-T is used in this area,

and that  there is  a close correlation between the amount of

2,4,5-T  used by  month and the size of the increase in the

frequency of miscarriages two months later.  Information has

recently  become  available to the Agency which documents the

use of silvex  in the Alsea area during the period of time
T/  A  Committee  of  the National Research Council of Canada
recently  agreed  with the  authors of the World Health
Organization's monograph, on TCDD that "for TCDD a no-
effect  level  for man could not be established" (NRCC 1978).

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studied.  However, even without  this  information,  I would




have found that the serious implications  of  this  study  are




as applicable to silvex as to 2,4,5-T.  TCDD,  the  contaminant




contained in both herbicides, is  a  potent  mammalian fetotoxin




and teratogen at very  low doses.  Conversely,  silvex and




2,4,5-T are  fetotoxic  and teratogenic  at  comparatively  high




doses.  It is reasonable to assume  that the  adverse human




reproductive effects observed in Alsea which have  been




attributed to low-level exposure to 2,4,5-T  are due primarily




to the TCDD  in  2,4,5-T.  Therefore,  since silvex also




contains TCDD,  I conclude  that  the  Alsea  data are  applicable




to areas where  silvex  is used when  evaluating potential




reproductive risk  to humans.




        I also conclude that  it  is prudent to assume that




individuals  living  in  or  frequenting areas where the




forestry use of silvex occurs  may experience exposure to




TCDD  qualitatively  similar  to  that  experienced by the Alsea




women and  may  suffer  the  adverse effects  which silvex,




2,4,5-T,  and/or TCDD  produce.   I further  conclude that




individuals, living in or  frequenting areas where the use




patterns  of  silvex create  similar or greater possibilities




for  exposure than  the  forestry  use, have  a potential risk of




adverse effects from  silvex exposure.  A comparable risk




potential  is applicable to persons  who are occupationally




exposed to  silvex  through  these uses.  Such use patterns




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include, without necessarily being limited to, the rlg'h't's-
of-way and pasture uses of silvex.  Additional uses c,
silvex (home and garden, aquatic weed control/ditch tL-ik,
and commercial/ornamental turf uses) are comparable to uses
of 2,4,5-T cancelled or suspended in 1970 because of concern
that exposure to 2,4,5-T and/or TCDD posed an imminent
hazard to humans and to the environment.  Because silvex
also contains TCDD, I conclude that it  is prudent to take
similar action for these silvex uses.   The Agency has
identified pesticide applicators and persons involved in
pesticide application support activities, and persons living
in or frequenting areas of  silvex   use  as the principal
groups of individuals who may be exposed as a result of
the forestry, right-of-way, pasture, home and garden,
aquatic weed control/ditch bank, and commercial/ornamental turf
uses of silvex.  Based upon animal data and other information
(including the recent Oregon study), individuals exposed to
silvex may suffer adverse reproductive  effects or develop
cancer.
     B.  Determination of Benefits
       The Agency has evaluated the economic effects of
cancelling non-crop uses of silvex.  The non-crop uses of
silvex include those it has in common with major uses of
2,4,5-T (forestry, pasture, and rights-of-way), as well as
turf (home and garden and commercial/ornamental turf) and
aquatic weed control/ditch bank uses.
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       Domestic usage of silvex is estimated to be about 2.8




to 3.3 million pounds annually.  Commercial/ornamental turf




and home and garden uses of silvex are the largest volume



uses, comprising more than 50% of domestic usage.  Aqtfatic




weed control/ ditch bank usage account for about  8% of



annual usage.  Other uses, primarily pasture,  account for




about 10% of use.  The uses of  silvex subject to this cancel-




lation notice account for about two-thirds of  its  annual



usage.



       The Agency's analysis indicates that cancellation of




silvex non-crop uses would not significantly affect U.S.



production or prices of  any commodities  or services in



affected sectors.  Economic impacts of the cancellation



would be minor  in most cases,  even at  the  local/regional



level.  The major significance of cancelling silvex is  that



it would not  be available to replace 2,4,5-T on  forest  and



pasture sites.




       The economic  impacts of cancelling  each of the non-



crop  uses of  silvex  are  discussed below.




      (1)  Forestry



       The cancellation  of  forestry  uses of  silvex would




not  have any  significant economic impact because  the  chemical



is not now in use.   The  principal potential  useis, the




Department of the Interior  (USDI) and  the  U.S.  Forest



Service (USFS), have already discontinued  "se.   The signifi-




cance of the  silvex  cancellation  for fores-t^y  use is  that,  it



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would not be available  as  a  substitute  for  2,4,5-T.   However,




silvex is not an  acceptable  substitute  for  2,4,5-T on aany




acres because it  is  toxic  to pines.   Thus,  impacts would




be limited  to non-pine  Western  conifer  forests  and some




Northeastern fir  spruce stands.




       Silvex has  been  used  in,forestry mostly  by  the U.S.




Department  of the  Interior,  on  parts  of approximately 2




million acres of Bureau  of  Land  Management  (BLM)  lands;




lesser amounts have  been used by  the  USFS.   Silvex is used




prior to planting  for site preparation  and  later to  assist




growth of young trees by "releasing"  them  from  competing




hardwood trees and brush.




       There are many alternatives  to. silvex for site




preparation.  Several chemicals (2,4-D,  pic loram, Atrazine,




Banvel,  and dicamba), as well as  mechanical, methods,




controlled burning,  and  combination methods,  may be




effectively used for this  purpose.




       Release of young  conifers  requires  a selective




herbicide or manual  methods  to  reduce hardwood  competition.




Silvex,  2,4,5-T, and 2,4-D are  the  only Federally registered




chemicals providing  this selective  control.   Silvex  and




2,4,5-T are preferred because 2,4-D controls  a  more  limited



spectrum of woody  species.




       Silvex is not widely  used  in forest  site  preparation/




release activities.  So  far  as  is known, the  only extensive




recent use of silvex has been by  BLM  in  western  Oregon.




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However, BLM has used no herbicides since 1977.  The USFS




treated approximately 2,700 acres of  forest  lands wicU  1,750




Ibs of silvex in 1977.  USDI is presently considering




prohibiting the use of silvex.  Plans have been  developed




for vegetation management without silvex.




     (2)  Rights-of-Way                   ,




       The economic impact of cancellation of  the use of




silvex on rights-of-way would be minimal.  Chemical, manual,




and mechanical methods are used on highway,  electric,,




railroad, and pipeline rights-of-way  acres to  control woody




and.herbaceous plants that would otherwise impede, the use




of  equipment, interfere with  inspection  and  maintenance and




in  extreme situations interfere with  the  functioning of the




right-of-way  system.




    .'„ - Manual and  mechanical  methods  are  the most common




control  practices  on  rights-of-way  acreage.   Present  usage




of  silvex for rights-of-way vegetation  control is minimal,




e.g.,  less than  2% of rights-of-way  firms use  it.   If




silvex were not  available,  users could  treat with other




herbicides.   Dichloroprop,  2,4-D,  and.picloram mixed with




2,4-D  are all cheaper than  silvex,  and  in some instances are




more  effective;




      (3)  Pasture




       The phenoxy herbicides  (2,4-D, 2,4,5-T  and silvex)




are registered  for the control  of .many  woody and herbaceous




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weeds on pasture.—   Silvex  is -generally  more  effective  for

woody plant control  than  2,4-D,  but  less  effective  that!

2,4,5-T.  No more than  250,000  Ibs  of  silvex are  used  oa'

pasture acreage each year.

       Other chemicals,  such as  pelleted  formulations  of

picloram, dicamba, 2,4-D  are generally preferred  to silvex

for  pasture use.  Therefore, farmers-who  currently  use

silvex would turn to these  alternative herbicides.   The  use

of alternatives would  prevent reductions  in yield or pro-

duction.  Therefore, there  would be no impact on  consumer

prices, or the  general  economy.   Agricultural income may  be

reduced by an  immeasurably  small amount.

      (4)  Commercial/Ornamental  Turf                   •-''

       Silvex  is used  on  various types of commercial and

ornamental turf, such  as  golf courses, athletic fields,

parks, playgrounds,  highway  turf, and turf farms. Golf

courses are the principal use.   Annual usage could be   >'

as much as 2 million pounds  of active ingredients.

       Effective alternatives are available.  Among them

are  2,4-D, MCP.P, and dicamba.  Use of alternatives could

increase  costs by  about $3.50/acre.  However, the use of

these more expensive alternatives would not add substantially
^Y   Pasture is  defined as land producing forage for animal
consumption,  harvested by grazing,  which has annual or more
frequent  cultivation,  seeding, fertilization, irrigation,
pesticide application  an^d other similar practices applied
to  it.   Fencerows enclosing pastures are included as part
of  the  pasture.

                              -10-

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to overall turf maintenance costs in most situations.  For




example,  turf maintenance for golf courses now costs




approximately $80-90 per acre.  Thus, the economic impact of




cancelling, silvex use would not be highly significant.




     (5)   Home and Garden




       Several hundred thousand pounds of silvex are used




per year  on home lawns and garden areas.  Most of  the




herbicides used by homeowners in the U.S. are for  control of




broadleaf weeds and grass pests in lawns.  However, most




homeowners do not use any herbicides.




       Several equally efficaceous alternatives to silvex,




are available and comparable  in cost.  Homeowners  could




shift to products containing  2,4-D, MCPP, and dicamba




without experiencing  inconvenience.  Thus, homeowner  impacts




stemming  from cancellation would be negligible.




     (6)  Aquatic Weed Control/Ditch Bank




       Aquatic weeds  are  a nuisance  in water  bodies  used  for




recreatibn  and in  farm ponds  used  for watering  livestock.




Major uses  of herbicides  for  aquatic weed control*are




government  and private recreational  organizations  and




farmers.  Economic  effects of cancelling aquatic/ditch




bank uses of  silvex would  be  nominal because  effective,




economical  alternatives  (2,4-D, diquat,  endothall, dichlobenil,




and biological controls)  are  generally available.






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     C.  Conclusion


       On the basis  of  information  currently  available,


I conclude that  the  risks  posed  by  the  continued use  of


silvex on forests, rights-of-way,  pastures, homes  and


gardens, commercial/ornamental  turf and aquatic weed  control/


ditch bank areas  in  accordance  with current terms  and
i

conditions of registrations  and  commonly recognized practice


appear to outweigh the  benefits  of  these uses.  For these


reasons, I conclude  that  these  uses of  silvex appear  to generally


cause unreasonable adverse effects  on the environment  [see


FIFRA Section 2(bb)]  when  used  in  accordance  with  widespread


and commonly recognized practice.   Accordingly, I  am  hereby


initiating proceedings  to  cancel the registrations of  all


pesticide products containing silvex registered for forestry,


rights-of-way, pasture, home and garden, commercial/ornamental


turf and aquatic  weed control/ditch bank uses.


IV.  PROCEDURAL MATTERS


     This Notice  initiates an action to cancel the


 registrations of the forestry,  rights-of-way, pasture,


home and garden,  aquatic weed control/ditch bank,  and


commercial/ornamental turf uses  of  silvex.—    Under


Section 6(b) and  3(c)(6) of  FIFRA  [7 U.S.C. 136d(b);  7


U.S.C. 136b(a) (c)(5)J  registrants  and  other  interested
T7Other procedural matters relating  to  the emergency
actions are presented  in the accompanying order suspending
the uses in question.
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 persons  may  request  a hearing on the cancellation actions

 that  this  Notice  initiates.   This section explains th<2

 prohibition  against  ex parte  communications,  when and how

 affected persons  may request  a hearing,  and the consequences o|

 filing or  of  failing to file  a request  for a  hearing in

 accordance with  the  procedures specified in this Notice.—^

      A.   Ex  Parte  Communications

      The Agency's  Rules of Practice  for  hearings conducted

 pursuant to  Section  6 of FIFRA forbid  the Administrator,

 the Judicial  Officer,  and the Administrative  Law Judge, at

 all stages of the  proceeding, from  discussing the merits  of

 the proceeding ex  parte with  any party or with any person

 who has  been  connected with the  preparation of presentation

 of the proceeding  as an advocate or  in an investigative or

 expert capacity,  or  with any  of  their  representatives.  (40

 CFR Section  164.7).

      Accordingly,  the following  Agency officers, and the

 staffs thereof,  are  designated to perform all investigative

 and prosecutorial  functions in this  case:   the Office of


 4/  Although  Section 6(b) of  FIFRA  generally  requires prior
 review of  and comment  upon proposed  notices of intent to
 cancel or  change  classification  by  the Secretary of  Agricul-
 ture  and  a Scientific  Advisory Panel,  I  am specifically
 authorized to waive  such requirements  and  proceed in accord-
 ance  with Section  6(c)  of FIFRA  whenever I find  that  sus-
 pension  of a  pesticide  registration  is necessary to  prevent
 an imminent hazard to  human health.  I have found that
 immediate suspension of the registrations  of  pesticide
 products containing  silvex is  necessary  to prevent an
 imminent hazard to human health  (see Emergency Suspension
Order and Notice of  Intent to  Suspend Uses of  SiIvex,issued
this day).  I hereby  invoke my authority  to waive the
external review requirements.                  *

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Toxic Substances, the Office  of  Pesticide  Programs, the

Office of General Counsel,  and  the  Office  of Enforcement.

     From the date  of this  notice  until  any decision,

neither the Administrative  Law  Judge,  the  Judicial Officer

nor myself shall have any  ex  parte  contact or  communication

with any investigative  or  trial  staff  employee,  or any

other interested persons not  employed  by EPA,  on any  of  the

issues involved in  this proceeding.  However,  persons

interested in this  case should  feel free to contact  any

other EPA employee,  including both  investigative and  trial

staff, with any questions  they  may  have.

     B*  Procedures  for Requesting  a Hearing

     (1)  When a Hearing Must be Requested
          for Cancellation  Actions

       Registrants  affected by  cancellation actions  initiated

by this Notice may  request  a  hearing within 30 days  of

receipt of this notice, or  within  thirty days  of the  date of

publication of this  notice  in the  Federal  Register whichever

occurs later.  Any  person  adversely affected by  the  cancel-

lation actions initiated by this Notice  may request  a

hearing within thirty days  of the  date of  publication of

this Notice in the  Federal  Register.

     (2)  How t o Re q ue s t a  Hearing

       All registrants  and  other interested persons who

request a hearing must  follow the Agency's Rules of Practice

Governing Hearings  (40 CFR, Part 164).   These  procedures

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specify, among other things, that:  (1) all requests for a

hearing must be accompanied by objections that are specific

for each use for which a hearing  is requested [40 CFR

164.20(b)], and (2) that all requests must be received by

the Hearing Clerk within the applicable thirty (30) day

period [40 CFR 164.5(a)].  Failure to comply with these

requirements will automatically result in denial of the

request for a hearing.

       Requests for hearings must be submitted to:

               Hearing Clerk (A-110)
               U.S. Environmental Protection Agency
               401 M Street, S.W.
               Washington, D.C.   20460
     C.  Consequences of Filing or Failing  to
         File a Hearing Request

       If a hearing  is requested on  any cancellation  action

on a silvex use initiated by  this Notice  before  the end

of the 30-day notice period,  the hearing  will  be  governed  by

the Agency's rules of practice  for hearings  under FIFRA

Section  6 (40 CFR, Part  164).   In the  event  of a hearing,

the cancellation  action(s)  subject  to  the hearing will not

become effective  except  pursuant to  orders  of  the Administra-

tor at the  conclusion of  the  hearL
       FEB 28 B?9
Date:
                                 Douglas
                                 Adoinis
                            -15-

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      DECISION AND EMERGENCY ORDER SUSPENDING
         REGISTRATIONS FOR CERTAIN USES OF
2-(2,4,5-TRICHLOROPHENOXY) PROPIONIC ACID (SILVEX)
   UNITED  STATES  ENVIRONMENTAL  PROTECTION  AGENCY
              WASHINGTON,  D.  C.  20460
          Office of Pesticide Programs
                 February  28,  1979

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                     Suspension  Order


       Registrations issued under  the Federal Insecticide,

Fungicide and  Rodenticide Act  (FIFRA), as amended,  7  U.S.C.

Section  136  e_t. ,  seq. of all pesticide products containing

2-(2,4,5-trichlorophenoxy) Propionic Acid (Silvex)  for  the

forestry uses  (including site  preparation, conifer  release,

and brush and  weed control), rights-of-way uses (including

                                       */
brush  and weed control), pasture  uses— ,  home and garden

uses,  commercial/ornamental turf  uses (including recreational

area uses),  and aquatic weed control/ditch bank uses  are

hereby suspended and the sale,  distribution, or other

movement in  commerce, and the  use of all such pesticide

products for the foregoing u^esj isf /prohibit ed.
                       Douglas/M.
                          Adminis
Date:
        FEB 18  I979
JV Pasture is defined as  land producing forage  for  animal
consumption,  harvested by  grazing, which has  annual or more
frequent  cultivation, seeding,  fertilization, irrigation,
pesticide application, and other similar practices
applied to it.   Fencerows  enclosing pastures  are  included
as part of the pasture*

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Decision and Emergency Order Suspending Registrations for
Certain Uses of 2-(2,4,5-Trichlorophenoxy) Propionic Acid
(Silvex)

I.  INTRODUCTION

       During the past two years, the Agency has been

gathering information about the closely related phenoxy

herbicides, 2-(2,4,5-trichlorophenoxy) propionic acid

(silvex) and 2,4,5-trichlorophenxoy acetic acid (2,4,5-T),

as part of  its Rebuttable Presumption Against Registration

(RPAR) process in order to decide whether the registration

of this pesticide should be continued.  This review was

prompted by studies showing that silvex,  2,4,5-T, and/or

their dioxin contaminant, 2,3,7,8-tetrachlordibenzo-p-

             */
dioxin  (TCDD)—' , caused reproductive  and  oncogenic effects

in test animals. During the public debate initiated by the

2,4,5-T RPAR  (43 FR 17116, April 21,  1978), the Agency

received reports that women living  in the vicinity of Alsea,

Oregon, had miscarriages  shortly after  2,4,5-T was sprayed

in the  forest  areas where they  reside.  The Agency investiga-

ted  the circumstances surrounding  these reported miscarriages
 */   Current  methods  for manufacturing  silvex  produce  TCDD as
 a by-product of  the  manufacturing  process.  Although silvex
 manufacturers attempt to remove  this contaminant,  TCDD
 cannot  be completely removed.  An  EPA  contract  laboratory
 has  measured the TCDD content  in 8 recently produced
 commercial samples of technical  grade  silvex  from  two
 different manufacturers. The contractor  reported that the
 TCDD content in  these samples  ranged from  0.012 to 0.024 ppm
 TCDD (limit  of detection:  0.01 ppm). Therefore, because TCDD
 is present as a  low-level  contaminant  in commercial samples
 of silyex, references in this  document to  "silvex" or the
 "pesticide product"  mean silvex  that is  contaminated  with
 TCDD.

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and compared the frequency of miscarriage  in the Alsea area

with comparable data from a control area.  The Agency has

concluded that the use of 2,4,5-T over a six-year period in

the Alsea area was related to a  statistically significant

increase in the frequency of miscarriages  by women residents

of the area, and that these miscarriages occurred shortly

after the use of 2,4,5-T in the  area where these women

resided.

    Based on this and other information, I am ordering

several emergency suspensions under FIFRA  Section 6(c),

which halt the distribution, sale, and use of 2,4,5-T for
                                     ** /
forestry, rights-of-way, and pastures—' until the completion
                                      */
of further administrative proceedings.—    Because both

silvex and 2,4,5-T are contaminated with TCDD, and because

of similarities in chemical structure, manufacturing processes,

use patterns, and effects in experimental  systems, I consider

it prudent to take similar regulatory action against silvex.

I am therefore ordering emergency suspension of the forestry,

rights-of-way, and pasture uses  of silvex  because I find

that they pose an "imminent hazard" to humans and to the
**/  Pasture  is defined as land producing forage for animal
consumption,  harvested by grazing, which has annual or more
frequent cultivation, seeding, fertilization, irrigation,
pesticide application, and other similar practices applied to
it.  Fencerows enclosing pastures are included as part of
the pasture.
^J  For details, see the risk discussion in Section IV of
this document and the 2,4,5-T suspension document, published
simultaneously with this document.

                       -2-

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environment; I also  find  that  an  "emergency"  exists because




there not enough time  to  hold  a  suspension hearing before




the next spraying  season.




       In addition,  I  am  ordering the emergency suspension




of the home and garden,  aquatic  weed control/ditch bank, and




commercial/ornamental  turf  uses  of silvex.  These additional




uses of silvex are  comparable  to  uses of 2,4,5-T cancelled




or suspended in 1970 because  of  concern that  exposure to




2,4,5-T and/or TCDD  posed an  imminent hazard  to humans and




to the environment.  I  now make similar findings of imminent




hazard for these uses  of  silvex.   I also find that an




emergency exists relative to  these uses because there is not




enough time to hold  a  suspension hearing before the spring




and early summer period  of  major silvex application for home




and garden, aquatic  weed  control/ditch bank,  and commerical/




ornamental turf uses.   In addition, I find that the year-round




application of silvex  in  certain areas of the country adds




to the urgency of  the  situation  for the home  and garden and




commereial/ornamental  turf  uses.




II.  LEGAL AUTHORITY




     A.  Standards  for Maintaining a Registration




       In order to  obtain a registration for  a pesticide




under FIFRA, a manufacturer must  demonstrate  that the




pesticide satisfies  the  statutory standard for registration.




That standard requires (among  other things) that the pesticide






                          -3-

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perform its intended  function  without  "unreasonable  adverse




effects" on the environment  [FIFRA Section 3(c)(5)].




"Unreasonable  adverse  effect on the environment"  means  "any




unreasonable risk  to  man  or  the environment,  taking  into




account the economic,  social and environmental costs  and




benefits of the use  of any  pesticide"  [FIFKA Section  2(bb)].




In effect, this standard  requires a finding that  the  benefits




of each use of the pesticide exceed the risks of  the  use.




The burden of  proving  that  a pesticide satisfies  the  regis-




tration standard rests with  the registrant and continues  for




as long as the registration  remains in effect [Environmental




Defense Fund v. Environmental  Protection Agency,  510  F.2d  1292,




1297  (D.C. Cir., 1975); Environmental  Defense Fund v.




Environmental  Protection  Agency, 465 F.2d 528, 532 (D.C.Cir.,




1972)].  Under Section 6  of  FIFRA, the Administrator  is




required to cancel the registration, or change the classifi-




cation, of a pesticide whenever he determines that the




pesticide no longer  satisfies  the statutory standard  for




registration.




      B.  Purpose and  Standard  for Suspending a Pesticide




      The suspension  provisions in Section 6(c) of the




statute give the Administrator authority to take  interim




action until completion of  the time-consuming procedures




required to reach  final cancellation decisions.   Under  this




Section, the Administrator  may suspend the registrations  of




a product and  prohibit its  distribution,  sale, or use during




cancellation proceedings  upon  a finding that  the  pesticide




                          -4-

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poses an "imminent  hazard"  to humans or the environment.


"Imminent hazard"  is  defined by the statute to mean that:

                              a
         The continued  use  of pesticide during the


         time  required  for  cancellation proceedings


         would be  likely  to result in unreasonable


         adverse effects  on the environment or will


         involve unreasonable hazard to the survival of


         a species  declared endangered by the Secretary


         of the Interior  under Public Law 94-135.


       As discussed  above,  "unreasonable adverse effects


on the environment"  means  that the risks from use of a


pesticide outweigh  the  benefits of its use.  Thus, in order


to find an imminent  hazard, it is necessary to find that the


risks of use during  the  period likely to be required for


cancellation proceedings  appear to outweigh the benefits.


The Administrator may not  suspend a pesticide without


having issued  a notice  of  his intention to cancel the


registration,  or to  change  the classification, of the


pestic ide.


       Suspension  is  the  Administrator's tool for quickly


correcting a situation  which endangers public health.  The


courts have repeatedly  held that "the function of a suspension


decision is to make  a preliminary assessment of evidence,


and probabilities,  not  an  ultimate resolution of difficult


issues" [Environmental  Defense Fund v. Environmental Protec-


tion Agency, supra,  510  F.2d at 1298].  "It is enough if


                          -5-

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there is a substantial  1 ike 1ihood  [emphasis  in original]




that serious harm  will  be  experienced  during the  year  or  two




required in any realistic  projection of  the  administrative




(cancellation) process"  [Environmental Defense Fund,  Inc. v.




Environmental Protection Agency,  510 F.2d  1292,  1297,  (D.C.




Cir. 1975) quoting from Environmental  Defense Fund,  Inc.  v.




Environmental Protection Agency,  supra,  465  F.2d  540  (D.C.




Cir. 1972)].  Moreover,  the  registrant bears the  burden of




proof during a suspension  proceeding because, as  indicated




above, the burden  of  proof under "FIFRA always resides  with




the proponent of registration  throughout the life of  a




registration.  (See,  e.g.,  Environmental Defense  Fund  v.




Environmental Protection Agency,  510 F.2d  at 1297;  Environmen-




tal Defense Fund v. Environmental  Protection Agency,  supra,




465 F.2d at 532.)




     C.  Types of  Suspension Proceedings




       In this order, I have begun emergency suspension




proceedings.  This is not  the  only type  of suspension




provided in FIFRA.  Section  6(c)  provides  for two kinds




of suspension proceedings:   ordinary suspensions  [FIFRA




Section 6(c)(2)J and  emergency  suspensions [FIFRA Section




6(c)(3)].  I have  chosen to  discuss  both kinds of suspension




because the procedures  applicable  to each  action  are  inter-




twined and because of the  complexity of  the  suspension




provision as a whole.






                        -6-

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       (1)  Ordinary Suspensions
       The Administrator may begin an ordinary suspension
when he finds that action is required to prevent an "imminent
hazard."   An ordinary suspension is not effective immediately;
instead,  the Administrator is required to give registrants
notice of his intent to suspend and to allow five days for
them to request a hearing.  Only a registrant may request a
hearing.   If a hearing is not requested within five days,
the suspension order becomes final and is not reviewable by
a court.   If a hearing is requested, the Administrator is
required  to convene an expedited proceeding at which other
interested persons can intervene.  The sole issue at a
hearing is whether an imminent hazard in fact exists.  The
procedures for conducting the hearing, with limited exceptions
discussed below, parallel the hearing procedures for an
emergency suspension.  The Administrator decides whether to
affirm his imminent hazard determination at the conclusion
of the hearing; if he does, he issues a suspension order.
This order is accompanied by a notice of intent to cancel
the registration, or to change the classification, of a
pesticide (if one has not previously been issued).  A final
order on  suspension following a hearing is reviewable in the
Court of  Appeals.
       (2)  Emergency Suspensions
       Before issuing an emergency suspension order, the
Administrator is required to make two findings:  (!) that
                       -7-

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the pesticide poses an "imminent hazard"  and  (2)  that  an

"emergency" exists.  An "emergency"  exists  when  the  situation

"does hot permit  [the Administrator]  to hold  a hearing

before suspending"  IFIFRA  Section  6(c)(3),  7  U.S.C.  136d(c)(3)]

The Agency interprets this  statutory provision to mean that,

if the threat of  harm to humans  and  to  the  environment is  so

immediate that  the  continuation  of a pesticide use is  likely

to result in unreasonable  adverse  effects - i.e.  the risks

outweigh the benefits - during  a suspension hearing, the

registration of any product  for  that use  may be  suspended

immediately— .

       An emergency suspension  order is  issued without

prior notice to registrants  and  takes effect immediately;

it remains in effect until  the  cancellation decision

if no expedited hearing is  requested.  If an expedited

hearing is requested on the  issue  of imminent hazard,  the

emergency order continues  in effect  until the issuance of  a
*y  The term  "emergency"  is  not  defined by FIFRA, and
the statute in  the  emergency suspension section does not
specifically  require  the  Agency  to balance benefits against
health and environmental  risk of pesticide use.  An alter-
native reading  would  be  that an  emergency exists whenever a
serious risk  could  result from pesticide use during the time
for conducting  a  suspension  hearing.   However,  for the
purpose of this proceeding I have decided to consider the
risks and benefits  in ordering an emergency suspension, just
as I balance  risks  and benefits  in deciding whether to
register a pesticide  or  to take  the pesticide off the market
through a cancellation or ordinary suspension order.  FIFRA
is a risk/benefit statute,  and I see  no reason  to depart
from this balancing test  in  issuing emergency suspension
orders .

                            _ 0_

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final suspension order. Registrants are given five days to



request an expedited hearing.  The hearing stage is to begin



within five days of the Agency's receipt of the hearing



request.  Unlike the ordinary suspension situation, no party



other than the registrant and the Agency may participate in



the expedited hearing on the emergency order, except to file



briefs.  The procedures for conducting the hearing are



otherwise the same as in an ordinary suspension.  For both



types of suspension, the hearing is to be conducted in



accordance with 5 U.S.C. Section 554.556 and 557 except that



the presiding officer need not be a certified hearing



examiner.  For both types of suspension, the presiding



officer shall have ten days from the conclusion of the



presentation of evidence to submit recommended findings and



conclusions to the Administrator.  The Administrator shall



then have seven days to issue a final order on the issue of



suspension.



       FIFRA provides for a special appeal of an emergency



suspension order to the District Court.  If an administrative



hearing is requested, an emergency suspension order is



subject to immediate review in District Court by the regis-



trant or by other interested persons with the registrant's



consent.  On the other hand, if no request for a hearing



before the Agency is made, the emergency order becomes



final and is not reviewable by any court [FIFRA Section



6(c)(2), 6(c)(3)].  The District Court action may occur



                       -9-

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simultaneously with the suspension proceeding before the




Administrator.




       The District Court reviews only whether the  emergency




finding is supported.  The standard  for review by the




District Court is very narrow—whether the  order of suspension




is "arbitrary, capricious, or an  abuse of discretion,  or




whether the order was  issued in accordance  with  the procedures




established by law"  iFIFRA Section 6(c)(4)].   If the District




Court  finds against  the Agency, it may stay the  suspension




order  until completion of the expedited suspension  hearing.




       The District Court order may  be appealed  to  the




Appellate Court by either the Agency or the registrant,




depending on the outcome.  A final order on suspension,




after  a hearing before the Agency, may be reviewed  in  the




Court  of Appeals on an expedited basis even though  related




cancellation proceedings may not have been  completed.




III.   SUMMARY OF FINDINGS




     A. Summary of Findings on Risk




       Numerous studies have clearly demonstrated that TCDD




and/or silvex contaminated with TCDD can produce fetotoxic,




teratogenic, and carcinogenic effects in experimental  animals




which  have been exposed to these  chemicals.  I  find  that  the




occurrence of these effects in test  animals indicates  that




humans who are exposed to TCDD and/or silvex may experience




comparable effects.






                         -10-

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       A recent  epidemic logical  study reported that women

living in the vicinity  of  Alsea,  Oregon (an area where

2,4,5-T and  silvex  were  extensively used),—  have a

statistically significant  higher  incidence of spontaneous

abortions (miscarriages)  than  women living in a control

area.  Specifically,  the  study shows that:

       (1) The  spontaneous abortion index for the Alsea

Study area where  2,4,5-T  is used  is significantly higher

than the index  for  urban  or rural control areas where there

is little or no  known use  of 2,4,5-T.

       (2) There  is  a significant increase in the abortion

index in the study  area  relative  to the control area in the

months of June  and  July.   This increase follows by approxi-

mately two months a  period in  March and April when 2,4,5-T

is used to control  vegetation  in  the forested areas in which

these women  live.

       (3) Statistical  analyses  of these data indicate that

there is a significant  correlation between 2,4,5-T used in

the study area  during the  spraying season and the subsequent

increase in  the  spontaneous abortion index in the study.

       This  relationship  between  exposure to 2,4,5-T

spraying and an  increased  incidence of miscarriages in

humans is not surprising.   This  is the same relationship

that has been demonstrated to  exist in test animals through
^7Althoughthe  study  addressed only 2,4,5-T usage, it
is now known that  silvex  was  also used in the Alsea area
during the period  of  the  study.

                          -11-

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 numerous  animal  studies.   While there are uncertainties


 concerning  the amount of  2,4,5-T and/or TCDD to which

                  Vjrmu. Kflv& bitty}
 the  Study area women' w-ep«~~ e x:p o s e d and concerning the


 precise  route (or routes) of human exposure, the statis-


 tically  significant incidence of miscarriages described


 above  makes it prurleB-t  for  the Agency to conclude that


 these  women in the Alsea  study area were exposed to 2,4,5-T.


 In  addition,  because of the relative toxicities of 2,4,5-T


 and  TCDD, the Agency concludes that it is reasonable


 to  assume that any adverse  reproductive effects attributable


 to  low-level  exposure to  2,4,5-T are primarily due to


 its  contaminant,  TCDD.   Since silvex contains TCDD, the


 Agency may  reasonably assume that exposure to silvex may


 also cause  adverse reproductive effects.


       Therefore,  the Agency concludes  that it is also

reoscoab/e-
 prudent  to  assume  that  individuals  may  be  exposed to silvex


 and/or TCDD who frequent  or  live  in areas  where  silvex is


 used in ways  and  under  conditions which may cause them to


 experience  exposure  opportunities qualitatively  similar


 to those  experienced  by the  Study area  women.   The  Agency


 has concluded  that silvex use  patterns  involving  exposure


 opportunities  qualitatively  similar to  those  experienced


 by the Study  area  women are  the forestry,  rights-of-way,


 pasture,  home  and  garden, commercial/ornamental  turf and


 aquatic weed  control/ditch bank uses  of  silvex.   The Agency


has identitfied pesticide applicators  and  persons involved in


pesticide application support  activities,  and  persons  living


                          -12-

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in or frequenting, areas  of  silvex  use  as the principal

groups of individuals who  may  be  exposed as a result of the

forestry, rights-of-way,  and pasture  uses of silvex.  Based

upon the animal test data  and  other information, including

the Alsea study, the Agency  has  concluded that individuals

exposed to silvex and/or  TCDD  may experience adverse

reproductive effects and  cancer.   Accordingly, the Agency

concludes that it is prudent to  regard  individuals who may

experience exposures qualitatively  similar to those

experienced by the Study  area  women as  a result of the

forestry, rights-of-way,  pastures,  home and garden,

commercial/ornamental turf and aquatic  weed control/ditch

bank uses,  as individuals who may  suffer reproductive

effects or cancer as a  result  of  these  uses of silvex.

     B. Summary of Finding_g_ on. Benefits During the
        Cancellation Proceedings

       The suspended uses  (forestry,  rights-of-way, pastures,

home, aquatic weed controI/ditch  bank,  and commercial/ornamental

turf) comprise about 67%  of  the  estimated 2.8 to 3.3 million

pounds of silvex used in  the United States.

       I find that the  economic  impact  of either an initial

3 1/2 month emergency suspension  or a 2-year suspension

will be insignificant,  based on  several considerations.

The inherent flexibility  in  the  tratment schedules permits

delays in treatment during the suspension period.  Alternative

chemicals, mechanical,  and manual control treatments are

available and are currently  being used.  Even though these

alternatives may not generally be as  cost-effective as

                            -13-

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silvex,  their  availability  will  minimize the impacts of




the  suspension period.   The major significance of a silvex




suspension  is  that  silvex would  not  be available for more




extensive  use  on  forest  and pasture  sites as an alternative




for  2,4,5-T.




      (1)  Forestry




        Use  of  silvex  in  forestry is  primarily for release




of  young conifers and  site  preparation activities.   However,




silvex  is  not  widely  used because of its relatively limited




control  spectrum  and  toxicity  to pines.   The only extensive




forestry use of silvex in recent years has  been by  the




Bureau  of  Land Management in Western Oregon.   (Use  of




2,4,5-T  and picloram was prohibited  or restricted by the




Interior Department in 1970).




        Several chemical, mechanical  (including  controlled




burning) and combination methods  are  available  as alternatives




for  site preparation.  Only  silvex,  2,4,5-T  and  2,4-D are




preferred for  the release of conifers; however,  for  this




purpose  2,4-D  has the most  limited control  spectrum.   Manual




methods  are also  available  for release activities.




        I find  that  the suspension of  the  forestry uses  of




silvex  for a 3 1/2  month or  2-year period would  not  have  any




significant economic impact, because  the  principal  past users,




the United States Department of  the  Interior  and  Forest Ser-




vice, have recently almost  completely  discontinued  use  of the






                          -14-

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herbicide.  Both agencies have already absorbed the additional



costs of using alternatives.



     (2) Rights-of-way



       Silvex is used to control woody and herbaceous plants



on railroads/ highways, electric transmission lines and



pipelines. Chemical, mechanical and manual methods of control



are often combined for use on rights-of-way acreage, with



manual and mechanical methods the most commonly used.



       If silvex were not available, users would use alternative



herbicides, since combinations of these provide equivalent



control, and are cheaper than silvex.  Therefore, I find



that suspension of silvex use for 3 1/2 months or two years



on rights-of-way would have no economic impact.



     (3) Pasture



       Silvex weed control  in pastures is now practiced



on only a very small proportion of the nation's pasturelands.



Generally, users prefer other chemical herbicides to silvex



for use in pastures.  There are effective chemicals and/or



mechanical control alternatives, although these alternatives



may be more expensive than  silvex.



       If silvex were not avaiable, current users would



probably adopt one of the alternative herbicides.  In so



doing, their incomes may be reduced by the small additional



cost of using the alternative.  I find that this impact of



a 3 1/2 month or 2-year suspension would be nominal.





                       -15-

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     C4)  Commercial/Ornamental  Turf




        Silvex  use  on  ornamental  turf  (golf  courses,  parks,




athletic,  fields, etc.) may  be  as high as  two  million pounds.




Use on  golf  courses  is extensive.  Silvex  is generally




applied in combination with other herbicides.   Use  of




combinations of  the  same  herbicides,  without  silvex, is




estimated to be  as effective and comparably priced.




        Without silvex, users would shift  to the readily




available alternatives.   I  find  that  the  economic impacts  on




this group of  users  would be minimal  if silvex were  suspended




for 3  1/2 months or  two  years.




     (5)  Home  and  Garden




        Most  homeowner use of herbicides in  the United States




is  for  control of  weeds  in  lawns.   Less than 25% of  the




U.S. homeowners  use  herbicides.   As with  use  on commercial/




ornamental turf, silvex  is  usually used on  lawns in  com-




binations with other  herbicides.   These combinations are




considered equally as effective  without silvex, and




comparatively  priced.




        If silvex were no  longer  available,  homeowners




would switch to the  alternative  combinations.   I find that




the impact of  suspension  for 3 1/2  months or  two years  would




be negligible.




     (6) Aquatic Weed Control/Ditch Bank




       Silvex  is used to  control  aquatic weeds in static




water areas  used for  recreation  and in  farm ponds used  for




watering livestock. It controls  submerged,  emerged and




                        -16-

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floating weeds. Essentially all  weeds controlled by this




use of silvex are  sensitive to other aquatic herbicides or




biological agents.




       Silvex is also  applied to drainage ditch banks and




canal levees. Although  there are no known chemical alternatives




for control of a few of  the weed pests found in these areas,




there are registered chemicals which are effectve against




many of them.  Manual  and  mechanical methods are also




avail able.




       I find that  the  suspension of silvex for 3 1/2 months




or two years would  not  be  a significant economic burden on




users for control  of weeds in static bodies of water,




because of the availability of effective, economical alterna-




tives.  The effect  of  a  suspension on ditch/canal users




would be somewhat  greater  because of the resistant weeds.




Nonetheless, I find that  the impact of the suspension of




silvex would be nominal.




     C.  Summary of Findings on Imminent Hazard




     (1) Forestry  Use




       In order to  find  an imminent hazard, I must find that




the risks of use during  the period likely to be required  for




cancellation proceedings  appear to outweigh the benefits.




The Alsea study, establishing correlation between use of




2,4,5-T in forest  management and miscarriages in humans,




coupled with animal studies showing similar effects, indicates




that there is a substantial likelihood that serious harm




could result to persons  with qualitatively similar exposure







                           -17-

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from the  forestry  use  of 2,4,5-T.   Because  of  the  high




probability  that the  adverse  effects  attributable  to  low




levels  of  2,4,5-T  are  primarily  due to  its  TCDD  contaminant,




comparable exposure to the  TCDD  contaminant in silvex would




result  in  similar  risk potentials.




        At  this  point,  because of the  voluntary discontinuation




of  the  forestry uses  of silvex by  the major users, there




appear  to  be  no risks  or benefits  of  its  use during a




cancellation  proceeding.  However,  since  forestry  use of




2,4,5-T is being suspended,  the  real  possibility of the




reinstatement of silvex must  be  considered.  In that  event,




I conclude that the risks of  the forestry uses of  silvex




outweigh  the  benefits.   The  economic  impacts of suspension




would be  small  because of the flexibility of treatment




schedules  and the  availability of  alternatives.   Hence, I




find that  an  imminent  hazard  exists for the forestry  use of




siIvex.




     (2) The Rights-of-Way Use




       The use  patterns of  silvex  for rights-of-way use




create the same, or greater,  potential  for  human exposure as




the forestry use.  Hence, the  rights-of-way use  results in a




hazard to human health  which  in  my  judgment outweighs the




corresponding benefits.  A use moratorium during the




cancellation proceedings would not  have a significant




economic impact because many  rights-of-way  managers  are






                         -18-

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likely to use alternate chemicals which are available and,



taken as a whole, are relatively similar in cost and effec-



tiveness.  Therefore, I find that an imminent hazard exists



for the rights-of-way use of silvex during the cancellation



proceedings.



     (3)  Pasture Use



       The use of silvex on pastures results in a lower



potential for exposure than the use of silvex in forestry



because silvex is applied in pastures for spot treatment by



knapsack spraying equipment.  The forestry use involves



substantial application by aerial methods., which have a



greater potential for creating drift than does ground



equipment.



       The benefits of pasture use of silvex are marginal.



Silvex weed control is practiced on a very small portion



of pasture acreage, showing the relative unimportance



of the chemical for this purpose.  Moreover, there are



effective chemical and/or mechanical control alternatives.



Hence, it is readily apparent that the risks to human



health outweigh the benefits of use during the cancellation



proceeding.  Accordingly, I find that the use of silvex on



pastures results in an imminent hazard.



     (4)  Commercial/Ornamental Turf



       The use of silvex on commercial and ornamental turf



creates the potential for the same, or greater, exposure  to



humans as the forestry use, and therefore presents a compar-



                       -19-

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able hazard to human health. Although use on commercial and
ornamental turf represents the largest single use of silvex,
a suspension of this use would not have a significant
economic impact.  Users would switch to readily available,
effective, economical alternatives. Therefore, I find that
an imminent hazard exists for commercial/ornamental turf
uses of silvex during the cancellation proceedings.
     (5) Home and Garden Use
       If the forestry use of silvex creates a potential
health hazard for humans, the home and garden use has an
even greater hazard potential.   In home application, there
are the additional problems of hand application by a non-
professional, unlimited application frequency and rates, and
high probability of bystanders.  The available alternatives
to silvex for home and garden use are effective and economical,
Because the potential risks from home and garden use of
silvex during the course of a cancellation proceeding
far outweigh any of the benefits of its use, I find that an
imminent hazard exists relative  to this use.
     (6) Aquatic Weed Control/Ditch Bank
       Silvex use for the control of aquatic weeds has the
potential for human exposure equal to or greater than that
likely from forestry use.  In addition to the exposure
possibly resulting from the actual application of the
herbicide, there is the possibility of exposure from contact
with the treated water. The suspension of the aquatic uses
                       -20-

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of silvex for static bodies  of  water  would  have no significant




economic impact, because  of  the  availability of alternatives;




the suspension of uses  for drainage  ditch banks and canal




levees would result in  a  nominal  economic impact.  Nevertheless,




when viewed as a whole, I  find  that  the potential  risks of




these uses outweigh the benefits.   Therefore,  I find that an




imminent hazard exists  for the  period of the cancellation




proceeding relative to  these uses.




     D.   Summary of Findings on Emergency




       As previously discussed,  I  have interpreted the




statutory provision on  emergency suspensions [FIFRA Section




6(c)(3)] to require a preliminary  balancing of risks against




benefits of use during  the time for  holding a suspension




hearing. Hence, an emergency finding involves two issues:




(1) immediate intervention is required because there is not




time to hold a suspension hearing  before the next period of




pesticide use; and (2)  the risks outweigh the benefits




during the time for holding  the suspension hearing.  At the




end of the suspension proceeding,  I  have discretion to




affirm,  modify, or reverse my suspension order.




     (1)  Forestry Use




       There is not enough time to hold a hearing before




the next forest spraying  season.  The next spray  season




begins in March.   I am  advised that  in some parts of the




Pacific Northwest, spraying  is about to begin or  has already




begun.  Hence, assuming silvex use on forests poses unreason-




                           -21-

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 able  adverse  effects,  immediate action is required to stop




 silvex  use.




        The  risks posed by silvex forestry use clearly




 outweigh  the  benefits  of use during the suspension proceeding




 which is  anticipated to run from March through June (see




 discussion  in Section  V below).  The Alsea study suggests




 that  persons  in the vicinity of forest spray are being




 exposed to  TCDD-containing herbicides, and consequently




 suffer  a  potential  risk from their use. Many scheduled




 silvex  treatments can  be deferred for the duration of




 cancellation  proceedings.  Therefore, those treatments can




 be  deferred during  the suspension proceedings.  In any case,




 alternatives  are often available for use in areas where




 treatment is  deemed essential.




        Accordingly,  I  find that an emergency exists for the




 forestry  use  of silvex.   Therefore, I am ordering immediate




 suspension of  all silvex registrations for these uses of




 silvex.




      (2)  Rights-of-Way  Use




        Silvex  is applied on rights-of-way (railways,  highways,




 electric  transmission  lines,  and pipelines)  during the




 spring  growth  season,  which is  due to start  in March  in some




 parts of  the  courntry.   Additionally,  some methods of




 application may be  year-round.   Hence,  there  is not enough




 time to hold  a  suspension  hearing  before  the  period of




maximum use of  silvex  on rights-of-way.




                           -22-

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       The risk of silvex use outweighs the benefits during
the time for holding the suspension proceedings.  As indicated
earlier, silvex poses a severe health risk to people living,
working, or passing through affected rights-of-way areas;
on the other hand, the benefits of use during the suspension
proceedings are very small.  On areas scheduled for treatment,
treatment can generally be postponed for the anticipated
3 1/2 month duration of a suspension proceeding.  Incremental
growth during the time required to hold a suspension hearing
is unlikely to be so great that treatment could not be
deferred.  Furthermore, there are effective and economical
alternatives for the small number of instances where weed
growth would interfere with equipment or endanger the safety
of a system's users.
       Accordingly, I find that an emergency exists for the
rights-of-way use of silvex.  Therefore, I am ordering an
immediate suspension of all silvex registrations for the use
of silvex on rights-of-way.
     (3) Pasture Use
       The application of silvex to restrict weed growth
on pastures is expected to occur in March in some parts
of the country and in even more areas before the anticipated
completion of the suspension proceeding in June.  Hence,
emergency measures are required to prevent human exposure to
silvex from pasture use during the suspension hearing.
                       -23-

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       As previously  noted,  the risk to humans  from  silvex
use on pastures  is  roughly comparable to the risk  to people
in treated  forest areas.  On the other hand,  the benefits of
use during  the 3- to  4-month suspension period  are virtually
nil.  Treatment  can most  certainly be postponed during
this  short  period.   In  any case, there are effective chemical
and/or mechanical control alternatives which can be  used in
areas where treatment cannot be postponed.
       Accordingly, I find that an emergency exists  for the
pasture  use of silvex.  Therefore, I am ordering immediate
suspension  of all silvex  registrations for the  use of silvex
on pastures.
      (4)  Commercial/Ornamental Turf
       Silvex is usually  applied to commercial  and ornamental
turf  during the  spring  and fall seasons.  Therefore, a
period of heavy  usage is  now pending.  Moreover, in  some
areas of the  country, use can be expected to be year-round.
There is not  enough time  to  hold a suspension hearing before
the period  of maximum use of silvex on commercial  and
ornamental  turf.
       The  potential  risks to human health from the  use
of silvex on  commercial/oraniental  turf outweigh the  benefits
of use during the time  necessary to hold a suspension
proceeding.  As  indicated  above,  the use of  silvex on
ornamental  turf during  this  period,  would pose  at  least the
same hazard as forestry use  for  a  similar period.  The
                       -24-

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benefits of use during  the  time  required for a suspension




proceeding would be minimal.   In most cases where treatment




was necessary during  this  period,  users would switch to




alternatives which  are  effective and comparably priced.




       Accordingly, I  find  that  an emergency exists  for the




use of silvex on commercial/ornamental turf.  Therefore, I




am ordering an  immediate  suspension of all silvex registra-




tions for the use  of  silvex on commereial/ornamental turf.




     (5) Home and  Garden




       Home and garden  use  of silvex normally occurs in the




spring and fall.   However,  as in commercial/ornamental  turf




use, application could  be  year-round in some areas  of




the country.  Therefore,  because of the nearness of  a




major usage  period,  and  the probability of continuous  use




in certain sections of  the  country, emergency measures  are




necessary to prevent  possible substantial human health




hazards during  the  course  of the suspension hearing.




       As previously  indicated,  the potential threat to




humans is probably  greater  from the home and garden  use of




silvex than from its  forestry use.  The fact that use  of




silvex by homeowners  is almost entirely aesthetic,  rather




than for other  purposes,  indicates that the economic benefits




of their use are marginal  at any time.  For the few  areas




where some control  method  may be necessary during the  period




of the suspension  proceeding, effective and economical




alternatives are available.




                            -25-

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       Accordingly, I find that  an emergency  exists  for  the




home and garden uses of  silvex.   Therefore, I  am  ordering  an




immediate suspension of  all  silvex registrations  for  this




purpose.




     (6) Aquatic Weed Control/Ditch  Bank




       The application of  silvex to  restrict  aquatic  weed




growth is generally begun  in the spring and continued




through early  summer. Hence,  there is  insufficient  time  to




hold a suspension hearing  before humans are exposed  to  the




potential risks to their health  due  to this use  of  silvex.




       The potential human risks  from  the  aquatic use




of silvex during the suspension  hearing clearly  outweigh




the benefits of use during that  limited period.   The  human




health hazard  is at least  as  great as  that from  forestry




use. The benefits to be derived  from the aquatic  use  of




silvex during  a suspension hearing are very small.   In most




instances, the use of any herbicide could be deferred for




this short period of time.   However,  for static water areas




where some herbicidal use would be necessary,  there are




available chemical alternatives;  for the few drainage ditch




and canal levee areas which contain pests resistant to




chemical alternatives,  manual methods could be used.




       Accordingly, I find that  an emergency exists for




the aquatic weed control/ditchbank use of silvex.  Therefore,




I am ordering  an immediate suspension of all silvex registra-




tions for these purposes.




                           -26-

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IV.   DETAILED FINDINGS CONCERNING  IMMINENT HAZARD AND EMERGENCY



       In Section III of  this  notice,  I have presented a



summary of my findings that  an imminent hazard and emergency


                          • ^                     *. Ifl-fld qqfcc
exist for the forestry, right s-of-way,  pasture, homejf^ IT



aquatic weed control/ditch bank,  and commercial/ornamental



turf uses of silvex.  The data,  information, and analyses



upon which these  findings are  based are detailed below.



     A.  Findings Relating to  Adverse  Effects in Test

         Animals



     (1) Adverse  Reproductive  Effects  in Test Animals



       This section  presents  the  test  animal data upon



which I relied in finding that exposure to TCDD and/or



silvex is likely  to  result in  adverse  reproductive effects



in humans.  Except as specified  below,  these data were



derived from studies  in which  pregnant  rodents or primates



were orally exposed  to the test  substance during the



second trimester  of  the gestational period.  The pregnant



rodents were sacrificed shortly  before  parturition, and



live fetuses were examined  for abnormalities.  The Agency



has extracted key data for presentation in this report



of findings.  Experimental details and  descriptions of the



underlying data  are  available  in the 2,4,5-T RPAR notice and



in the published  literature.
                              -27-

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       (a)  Exposure of Test Animals  to TCDD
       TCDD produces fetotoxic  effects such as death
and reduced fetal size; skeletal deformities such as cleft
palate and clubfoot; injury to  internal organs such as
intestinal bleeding, intestinal lesions,  and abnormal
kidneys; and post-partum  effects such as  reduced survival.
These effects appear in several different rodent strains and
species, occur  in all of  the litters  in some dose groups,
                ^3±J&S5JL)
and occur at doses Jas low as 0.01  ug  TCDD/kg.  The repeated
and regular appearance of several  different forms of damage
to test animals of several different  strains and species
indicates that TCDD is a  teratogenic  and  fetotoxic agent in
mammals.
       (i)  Fetotoxic and Embryolethal Effects
       Fetotoxic and embryolethal  effects have been reported
for at least three different mouse strains, two different
rat strains, and one strain of  subhuman primates exposed to
TCDD during gestation.  For example,  in studies using
generally low-dose regimens of  TCDD,  Neubert and Dillmann
reported that resorption  sites  (resorbed  or dead embryos)
occurred in 54% (7/13) of the litters at  0.3 ug/kg and in
100% (3/3) of the litters at 9.0 ug/kg for NMRI mice,
compared to 24-32% (23/95 and 24/65)  of litters exhibiting
resorptions in control animals  which  had  not been exposed to
TCDD.   Sparschu et al. reported resorption of 100% (110/110)
of the fetuses in Sprague-Dawley rats exposed to 8 ug
                       -28-

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TCDD/kgf compared to 20% resorption (63/309) of the fetuses
from the control animals.  Khera and Ruddick reported 100%
(77/77)  resorption of fetuses at 4 ug/kg and 36% (56/153) at
exposures of 1 ug/kg in Wistar rats, compared to 2-7% (3/152
and 10/127)  in the control animals.  Smith et al. reported
resorptions  in 95% (18/19) of the litters of CF-1 mice
exposed  to 1.0 ug/kg, compared to 74% (25/34) in the control
animals; despite the high control incidence of resorptions
in this  study, the increased incidence in the experimental
animals  was  statistically significant.  In an abstract of a
current  study, Schantz et al. (1979) reported 57% (4/7) of
pregnant monkeys aborted and one delivered a stillbirth.
Two others on the 50-ppt diet failed to conceive, and two
delivered normally.  The eight control animals all delivered
normal infants.  Maternal toxicity was observed in some dose
groups in some of these studies.
       Similar effects have been reported at higher dose
levels of TCDD.  Neubert and Dillmann reported that a single
dose of  45 ug/kg to NMRI mice on day 6 produced resorptions
in 100%  (3/3) of the viable litters, compared to resorptions
in 24% (23/95) of the control litters.  Courtney reported
an average of 87% mortality in 6 litters of CD-I mice orally
exposed  to 200 ug/kg, compared to an average mortality of 6%
in 15 vehicle control litters.  This investigator also
reported an average of 76% mortality in 6 litters of CD-I
mice exposed subcutaneously to 200 ug TCDD, compared to 14%
                       -29-

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in the six litters of control animals.  Some of these



studies also describe statistically significant weight



depression in the surviving embryos (e.g., Sparschu et al.).



       These and other studies also report that TCDD had no



measureable adverse effects at some dose levels in some



strains.  For example, Khera and Ruddick report no fetotoxic



effects at 0.125 ug/kg in Wistar rats, and Neubert and



Dillmann report no teratogenic effects at 0.3 ug/kg in NMRI



mice.  Courtney and Moore reported that TCDD had no effect



on fetal weight or embryonic mortality at 0.5 ug/kg in CD



rats, and Sparschu et al. reported no effect at 0.03 ug/kg



in Sprague-Dawley rats.



       Dow Chemical Company, a silvex registrant, has



recently completed a study of the effects of TCDD on re-



production in Sprague-Dawley rats exposed to low dose levels



of this chemical for three generations. The registrant



concluded that "impairment of reproduction was clearly



evident among rats ingesting 0.01 or 0.1 ug TCDD/kg/day.



Significant decreases were observed in fertility, litter



size, gestation survival, post-natal survival and postnatal



body weight."  In addition, exposure to 0.001 ug TCDD/kg



per day resulted in statistically significant increases in





                       -30-

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per day resulted  in  statistically  significant  increases in

the percentage of  pups  dead  at  birth  and/or dying  before the

end of three weeks of  life  in  some  generations.—

       Although the  experimental  protocols  and strains

differ for the several  studies  cited,  in each  case TCDD
                                                  lor-
significantly increased  the  incidence  of resorbed embryos f

relative to the rate  observed  in  control animals not exposed

to TCDD.  The regular  occurrence  of  embryonic  death in

studies by different  investigators  in  primates and in

different rodent strains  indicates  that  exposure to TCDD

during mammalian gestation may result  in the death of the

embryos and related maternal  reproductive failure.

       ( i i )  Skeletal  Anomalies

       Skeletal defects  appear in six  studies  involving four

different mouse strains.  Courtney  and Moore report the

following incidences  of  cleft  palate in  the indicated
*_l  Dow Chemical Company  has  claimed  that the results
of this study are "trade  secret"  or  "confidential."  An
injunction issued on April  4,  1978,  in the case of Dow
Chemical Co.  v. Costle, Civil  Action  No.  76-10087, U.S.
District Court for the Eastern District of Michigan (Northern
Division), arguably precludes  EPA from disclosing the data
from this study at the present time.   Although the relevant
provisions of FIFRA have  since been  amended to allow disclo-
sure of data such as this  [see,  e.g.,  FIFRA Section 10(d)
and 10(g)J, the injunction  has not yet been modified.  EPA
intends to promptly request  the  Court  to  modify the injunction,
but until this has been done  the  Agency will not publicly
disclose the data from the  study.  The summary presented in
the text of this Order does  not,  in  EPA's opinion, constitute
disclosure of the allegedly  "trade secret" data submitted  by
Dow and would not cause any  harm  to  Dow's legitimate competi-
tive interests.  The data  from the study  may be made available
to any party in a suspension  or  cancellation proceeding
under an appropriate protective  arrangement.

                           -31-

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strains exposed to 3 ug/kg TCDD:  71% (5/7) in litters of
                        \
C57BL/6 mice, compared to none  (0/23) in the controls; 22%

(2/9) in litters of DBA/2 mice  compared to none (0/23) in

the controls; and 30% (3/10) for CD-I mice, compared to none

(0/9) in the controls.  Neubert and Dillmann, also using 3 ug

TCDD/kg, reported 29% (7/24) of the viable litters had

fetuses with cleft palate for NMRI mice compared to 6%

(10/160) of the control litters.  Smith et al. reported

cleft palate in 71%  (10/14) of  CF-1 mouse litters at 3

ug/kg, compared to none (0/34)  in the controls.

       In exposures of shorter  duration, Moore et al.

reported cleft palate in 86% (12/14) of C57BL/6 mouse

litters exposed on days 10-13 to 3 ug/kg, compared to none

(0/27) in the control litters.  Neubert and Dillmann reported

cleft palate in 71% (10/14) of  litters of NMRI mice exposed

to a single 45 ug/kg dose on day 11, compared to 6% (6/95)

of litters in the controls.

       Courtney and Moore reported no cleft palate in any of

the litters in CD rats exposed  to 0.5 ug/kg.  Similarly,

Khera and Ruddick, using Wistar rats, reported that the

occurrence of the skeletal anomalies in the fetuses exposed

to 2.0 ug/kg was comparable to  the rate for the untreated

animals.

       (iii)  Injury to Internal Organs

       Exposure to TCDD produced injury to the kidneys and

intestinal tracts of at least five different mouse and rat

                       -32-

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strains.  Smith et al. reported 28% (4/14) of litters with
kidney anomalies at 3 ug/kg in CF-1 mice, compared to none
(0/34) in the controls.  Moore et al. reported 100% (14/14)
of litters with kidney anomalies in C57BL/6 mice exposed to
3 ug/kg on days 10-13, compared to none (0/27) in the
control litters.  Courtney and Moore reported kidney anomalies
in 100% (10/10) of the litters of CD-I mice at 3 ug/kg,
compared to 33% (3/9) in the controls, and 67% (4/6) litters
with abnormal kidneys in the CD rat at 0.5 ug/kg as compared
to none (0/9) in the  control litters.  Sparschu et al.
reported hemorrhages  or lesions in the intestine of 36%
(36/99) of the fetuses of Sprague-Dawley  rats exposed
to 0.5 ug/kg, compared to none (0/246) in the control
fetuses.
       (b)  Exposure  of Test Animals to Silvex
       Silvex has been shown to produce fetotoxic effects
such as fetal mortality, reduced body weight, skeletal
anomalies, and injury to internal organs.  The effects
have been observed in test rodent species at maternal
doses as low as 50 mg/kg (TCDD < 0.05 ppm).  These results
clearly indicate that silvex is fetotoxic and teratogenic
in mammals.
       Courtney—  reported significant incidences of
increased fetal mortality and reduced fetal weight  in CD-I
*7Courtney, K.D.  1977.   Prenatal  effects of herbicides:
evaluation by the prenatal  development  index.  Arch. Environ.
Contam. Toxicol.  6(1):33-46.
                       -33-

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mice which had received prenatal exposure to silvex.
Maternal subcutaneous exposure to 405 mg/kg silvex (TCDD <
0.1 ppra) resulted in 25% (33/132) fetal mortality and an
average fetal weight of 0.87 g, compared with control values
of 12% (19/171) and 1.03 g, respectively.  Oral exposure to
the same dose resulted in an average fetal weight of 0.83 g,
compared with 1.01 g in the controls.  An increased incidence
of cleft palate was also observed among the treated fetuses.
Oral exposure resulted in an incidence of 7% (7/95); subcuta-
neous exposure resulted in 3%  (3/99).  No cleft palates
(0/260) were observed among the control animals.
       Dow Chemical Company—'  studied the reproductive
effects of silvex and the propylene glycol butyl ether ester
of silvex (silvex-PGBE), each  containing less than 0.05 ppm
TCDD. Sprague-Dawley rats were exposed to 25 to 100 mg/kg on
days 6 through 15 of gestation.  Significant effects on
fetal mortality and birth weight were observed in the
litters of treated dams.  Skeletal anomalies, such as cleft
palate, retarded ossification, and extra cervical ribs were
observed among the exposed fetuses.  Micropththalmia (abnormal
smallness of the eyeball)  and circulatory system abnormalities
were also-seen.  Similar effects were observed when animals
were dosed with silvex-PGBE, or when dosed for three-day
intervals during the period of early organogenesis.
    Dow Chemical Co. has also requested confidentiality
for the results of this study.  The discussion in the
footnote in Section IV.A.(1)(a)(i) of this document
applies to these data.
                       -34-

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       In each of the studies cited above, some maternal

toxic effects were observed.  Courtney found increased

maternal weight gains and  increases in liver to body weight

ratios among the treated groups; Dow noted baldness (alopecia),

lack of appetite and vaginal bleeding.  However, the existence

of maternal toxic effects  does not negate the impact of the

observed injury to and death of the fetus.

     (2)  Oncogenic Effects in Test Animals; Exposure of
          Test Animals to  TCDD

       The Carcinogen Assessment Group (CAG) has concluded

that TCDD induces carcinogenic responses in mice and rats

at exceedingly low dose levels and that these effects,

together with data showing that TCDD is mutagenic, con-

stitute substantial evidence that TCDD is likely to be

a human carcinogen.

       Dow Chemical Company, a silvex registrant, studied

the effects of TCDD on male and female Sprague-Dawley

rats exposed to 0.022, 0.220, or 2.2 ppb TCDD.  CAG

agrees with the registrant's conclusion that there is a

statistically significant  increase in the incidence of

heapatocellular carcinoma  in female rats exposed to 2.2 ppb

TCDD.  In another study using Sprague-Dawley rats, Van

Miller reported that 1 ppb and 5 ppb TCDD produced a carcino-

genic response in the livers of male Sprague-Dawley rats.

These observations tend to confirm the registrant's observa-

tions that TCDD produces an oncogenic response in the livers

                       -35-

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                            ** /
of male Sprague-Dawley rats.—Further, a preliminary


report of a not-yet-completed National Cancer Institute


study tends to confirm these observations of a carcinogenic


response in rats.  A contractor for the National Cancer


Institute has reported that TCDD is carcinogenic in the rats


and mice used in that study.


       CAG also emphasized that, at low levels/ TCDD is


a potent inducer of arylhydrocarbon hydroxylase, an enzyme


system that contains an enzyme that is known to mediate


the formation of epoxides, compounds which are potentially


active carcinogenic metabolites.


       CAG also reported that TCDD is mutagenic in the


Ames test without the metabolic activation system.  Its


mutagenic activity is exhibited by frameshift mutations


caused by intercalation between base-pairs of DNA.


     B.  Findings Relating to Risk to Humans


     (1)  Study of Miscarriages in Alsea, Oregon


       The Alsea study detailed below was performed taking


into consideration only 2f4,5-T applications during the


reference period.  Information has recently become available


to the Agency which documents the use of silvex in the
**/  The CAG and an EPA audit found that this study had
major shortcomings in design and conduct that limited the
reliability of the data developed at dose levels lower than
1 ppb.


                       -36-

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                                              * /
Alsea area during the  period  of  time  studied.—    However,

even without this information,  I  would  have  found that  the

serious implications of  this  study  are  as  applicable  to

silvex as to 2,4,5-T.  TCDD,  the  contaminant  contained  in

both herbicides, is  a  potent  mammalian  fetotoxin and  teratogen

at very low doses.   Conversely,  silvex  and 2,4,5-T are

fetotoxic and teratogenic  at  comparatively high  doses.   It

is reasonable to assume  that  the  adverse human  reproductive

effects observed in  Alsea  which  have  been attributed  to

low-level exposure to  2,4,5-T are due primarily  to the  TCDD

in the 2,4,5-T. Therefore,  since  silvex also  contains TCDD,

I conclude that the  Alsea  data are  applicable to areas  where

silvex is used when  evaluating potential reproductive risk

to humans.

       (a)  General  Discussion

       In response to  the  2,4,5-T RPAR  notice,  a group

of eight women informed  the Agency  that they  lived within  12

miles of Alsea, Oregon,  where 2,4,5-T and silvex are  used  in

forest management and  that  they had experienced  a total of

13 miscarriages between  1972  to 1977.  In their  letter, the

women presented information showing that most of their


*7Herbicidespray  records for Alsea basin,  1972-1978
TEPA 1979).  Use of  silvex was also claimed by  the women in
the 2,4,5-T RPAR response  which prompted the  Alsea study
[2,4,5-T  RPAR rebuttal comment,  30000/26:#363].

                         -37-

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miscarriages occurred eight to ten weeks after conception
and followed by four or six weeks the date of the spring
application of 2,4,5-T in the forest areas in which these
women reside. The women indicated their belief that this
information suggested that the unusually high number of
miscarriages in their group was related to the use of
2,4,5-T and/or silvex.
       The effects which these women reported were comparable
to the embryolethal and fetotoxic effects observed in
test animals that have been exposed to 2r4,5-T and/or TCDD.
Moreover, because embryos are particularly susceptible to
the harmful or lethal effects of fetotoxic or teratogenic
agents during the early stages of pregnancy, the occurrence
of these miscarriages within approximately two months of the use
of 2,4,5-T in the Alsea area suggested a possible relationship
between the use of the pesticide and the miscarriages
reported for this group of women.  For these reasons, the
Agency began an epidemiological study to determine if the
occurrence of the spontaneous abortions in the entire Alsea
area (parts of three counties comprising 1,600 square miles)
bore any relation to the use of 2,4,5-T in the area. To
answer this question, the Agency gathered information and
data from hospitals on the occurrence of spontaneous
abortions in the Alsea Study area and compared these
data to comparable data from a rural area where there was
little or no known use of 2,4,5-T or other dioxin-contaminated
                       -38-

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phenoxy herbicides  (Control  area).  Data on spontaneous

abortions  from  an Urban area near Alsea were also reviewed

for the study.

       The Agency's  preliminary analysis of the data generated

through this  study  indicates that:

       (1)  The  spontaneous  abortion index—  (hospitalized

miscarriages  per  1,000  births)  for the Alsea Study area

where 2,4,5-T was used  was significantly greater than the

index for  the Urban  and Control areas where there was little

or no known use  of  2,4,5-T;

       (2)  There was  a dramatic increase in the spontaneous

abortion index  for  the  Study area relative to the Urban and

Control areas in  the months  of  June and July; this increase

followed,  by  approximately two  months, a period in March and

April when 2,4,5-T  was  used  to  control vegetation in the

forested Study  area; and

       (3)  Statistical analyses of these data indicated

that there was  a  significant correlation between the amounts

of 2,4,5-T used  in  the  Study area during the spraying

season and the  subsequent  increase in the spontaneous

abortion index  in the  Study  area.
^_l  The investigators  determined the spontaneous abortion
index by relating  the  number of hospitalized spontaneous
abortions to the number of live births, corresponding
to month of conception.   The ratio derived in this way
is express as  abort ions/1,000 births, related to month
of conception,  and  permits comaprison between areas of
different total population size.  The index is based on
a five-month moving  average for births to correspond with
monthly miscarriages  for  terms up to 20 weeks (about
five months).

                         -39-

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       In conclusion, the Agency's systematic survey of



the occurrence of spontaneous abortions in an area of



2,4,5-T use indicates that there was an unusually high number



of spontaneous abortions in the area, and that the incidence



of spontaneous abortions may reasonably be related to the



use of 2,4,5-T in the area. The data further indicate that



the miscarriage experiences which the eight Alsea women



reported to the Agency were representative of the experiences



of the larger population of women living in the Study area.



The data and information which provide the basis for these



conclusions are summarized below.



       (b)   Results and Analysis



       Comparison of the spontaneous abortion indices



for the Study, Urban, and Control areas for the period from



1972 through 1977 shows that women living in the Study area



where 2,4,5-T is used were more likely to experience



spontaneous abortions than women living in either the



Urban or Control areas (Table 1).  The six-year spontaneous



abortion index averaged 80.8 for the Study area, compared to



averages of 43.8 and 65.4 for the Urban and Control areas,



respectively.



       In addition to this general elevation in the Study



area spontaneous abortion index, there was a striking increase



in the Study area index for the months of June and July.



During June, the index in the Study area was 130.4, compared



to 44.9 and 46.0 in the Urban and Control areas, respectively.



                       -40-

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Table 1.  Monthly Spontaneous Abortion  Index  for  the  Study,
          Urban, and Control Areas  (Oregon, 1972-1977)
          —- •  • • • •  II  • . •! r _ -  _| _- - — .- - -.- ^_ 	\_ - __ „. -^rf- (,_,-— '- • T . • -- - __.!-•_,	._ J_
I Month
January
February
March
April
May
I June
i
1
1 July
August
September
October
November
December
[Average

Study Area
48.1
82.2
93.8
61.9
89.9
130.4
105.4
88.1
46.0
76.2
76.7
70.3

Urban Area
73.9
49.3
43.9
47.0
50.8
44.9
14.6
31.8
49.6
54.8
19.6
45.6

Control Area I Average I
1
82.0
28.1
48.1
97.5
63.2
46.0
55.3
79.8
85.3
50.5
54.3
94.5

1
68.0
53.2
61.9
68.8
68.0
73 .~8 f
I
1
58.4 |
r
66.6
60.3
60.5
50.2
70.1

80.8 I 43.8 1 65.4 | 63.3 I
1 1 1 	
                             -40a-

-------
For July, the indices were 105.4  for  the  Study  area,  compared

to 14.6 and 55.3 for the Urban  and Control  areas,  respectively,

These data are presented graphically  in Figure  A.

       The increased spontaneous  abortion  indices  in  the

Study area during June and July are particularly  significant

when viewed in terms of data on the use of  2,4,5-T in the

           */
Study area.—   Spraying records for the Alsea area for  the
j^/  The preliminary report inadvertently  included  3,530
pounds of silvex as 2,4,5-T in the  estimates  of  usage  in
the Study area.  Conceptually, this  flaw  is not  signifi-
cant:  1) since its effect would merely modify  slightly
the very significant correlation coefficient  between
herbicide use and miscarriages; 2)  the nature of the
relationship between time of application  and  the mis-
carriages is expected to remain unchanged;  and  silvex
contains TCDD and could be expected  to result in the same
effect.
    Nonetheless, the Agency immediately had the  analysis
rerun to determine whether specific  change  in numerical
estimates result.
    Corrected 2,4,5-T use remained  significantly correla-
ted with miscarriages occurring 2-3  months  later (r=72;
p<«°O.  Combined silvex and 2,4,5-T  spray data  were  also
correlated with miscarriages since  both compounds  could
be hypothesized to cause the observed effect  due to  a  com-
mon TCDD contaminant.  This analysis also showed strong
correlation between use and miscarriages  as would  be
expected on the basis of animal studies (r=.69;  p<.02).
    The relative insensitivity of the correlation  to
changes in quantity further demonstrates  the  inherent
strength of the relationship between the  basic  use pat-
tern and miscarriages occurring 2 to 3 months later.
                        -41-

-------
Figure A.   Plot of Monthly Spontaneous Abortion  Index for

                the Study, Urban,  and Control Areas
  130 .



  120



  110 -



  100 .



   90


 x

 5 BO
 c
 H

 c 70 J
 o
 1-1

 t; eo
 o
 XI

 « 50 .



   40 -



   30



   20 .




   10 -
                           •   • Study  Area


                           o	-e> Urban  Area


                           A	A Control  Area
            c
            m
Xi
0)
                      —r

                       M
                ~r~

                c
                   CO
                           ffl
a
0)
u
o
0
2
U
0)
D
                                 Month
                                   -41a-

-------
study period indicate that 2,4,5-T use occurs primarily



between March 1 and April 30; substantially lower amounts of



the pesticide are used during May and still lower amounts



are used during July and August (Figure B).  Examination of



this information on the use of 2,4,5-T in light of data on



the increased incidence of spontaneous abortions reveals



that this increase occurs approximately two months after the



period of annual application of 2,4,5-T in the Alsea area.



       More refined analysis of these data on total abortions



and total 2,4,5-T use by month during the period from 1972



to 1977 indicates that there was a statistically significant



correlation between the abortion index in the Study area



and the amount of 2,4,5-T used there.  That is, when the



increased spontaneous abortion index was compared to the



amount of 2,4,5-T used each month in the areas where the



women resided, the peak in the abortion index followed the



peak in the spray pattern by approximately two months. This



two-month lag time corresponds to the time predicted on the



basis of the initial reports from the eight Alsea women.



Because this correlation is statistically significant



(p<0.01), there is strong reason to suspect that the



spontaneous abortion increase was related to the use of



2,4,5-T.



       In view of the laboratory data establishing that



2,4,5-T and its contaminant TCDD have embryolethal effects



in test animals and the susceptibility of the young embryo



                       -42-

-------
Figure B.
Pounds of  2  4,5-T  Sprayed in Alsea Basin
    Accumulated  by Respective Month,  1972  through 1977,
    Compared  with  Abortion Index for  the  Same Period
                                           Pounds Sprayed
130 -
120

110 -

100 .
90
X
•S 80 _
c
H
c 70 .
o
t! 60 _
o
A
* 50 -
40 -



30

20
10







A
/ ^ 	
/
/
/
/
y









\
\
\
\
V











A >•
t-i ti X a
A






•
/
/
/










,

,
/
/

















\
\
\
\
\
















•




\
\
\
\














>, C '-t
4 (0 S3
S '








\
\
\
\
\

• Aoortion index







X
f "*
^
•
\/
t










C7>
3









- 5


0
0
0
.H
- 4 x
c.
OJ
•H
T!
a)
cr>
" 3 5
i— i
OJ
4J
U
rt.
_ o tj |
0
13
C
3
O
d.
- 1



D U 0 «
^ (-3 *c w o 20
                              Month
                                  -42a-

-------
to fetotoxic and teratogenic agents, the increased spontaneous

abortion index in an area of 2f4,5-T use may reasonably be

interpreted to be a consequence of the exposure of women

residents of the area to the 2,4,5-T used for forest

           */
management.—

     (2)  Seveso (Italy) and Vietnam

       (a)  Seveso, Italy

       On July 10, 1976, an accident at the ICMESA chemical

plant in the Seveso region of Italy released 2 to 10 pounds

of TCDD over a wide area.  Hundreds of animals died, many

area residents reported skin disorders, and an area of

110 hectares was evacuated.  The most pertinent reports on

this incident are provided by Reggiani  (1977), Tuchman-Duplessis

(1977), and Whiteside (1977; 1978).

      There is an apparent consensus that the reproductive

epidemiology of Seveso, as presented, does  not provide

firm evidence of increased risk of  spontaneous abortions  or

congenital malformations following  the  explosion.   The

Agency does not believe, however, that  those  investigations
 V  The Alsea experience  may not  be  an  isolated  incident.
 Reports of people  adversely affected by exposure to  phenoxy
 herbicides and/or  TCDD  have frequently  appeared  in medical
 and scientific  journals.   Recent  summaries  appear in IARC,
 NRCC, and U.S.  Air Force  documents on phenoxy  herbicides  and
 dioxins.  Further, as a result of the 2,4,5-T  RPAR,  the
 Agency recently received  numerous accounts  of  human  health
 effects attributed to phenoxy herbicides and/or  TCDD.  These
 have been summarized  in a document  included in the record.
 The cumulative  effect of  these reported incidents suggests
 that people  who live  and/or work  in  areas of 2,4,5-T use  may
 experience adverse health effects.

                        -43-

-------
provide sufficient evidence of the absence of increased
teratogenic risk in humans, either for dioxin in general or
among the women of Seveso in particular.  There are three
reasons for this conclusion:  (1) deficiencies in the
available data; (2) methodologic deficiencies in the treatment
and interpretation of the data which are available; and
(3) suggestive indications in the available data that there
may actually have been an increase in teratogenic risk in
the area after the incident.
      Major points which illustrate deficiencies in the
available data include:  reproductive data in the area
"either do not exist or are deliberately underreported"
(Reggiani 1977); baseline rates for spontaneous abortions
and congenital malformations in the area prior to the
incident are not available; less than complete cooperation
was obtained from local physcians and less than complete
registration of pregnant women was attained (623 pregnant
women were registered, but 2,513 deliveries were recorded in
the area for July 1976 to May 1977; registration was thus
about 25%); while 34 women obtained therapeutic abortions in
the area, it is estimated that more than 2 times that number
obtained them legally or illegally elsewhere (Whiteside
estimates the number to be 4 times as many);  and the
conventional pitfalls of reproductive epidemiology could not
be avoided (e.g., dependence on hospitalized spontaneous
abortions for numerators and hospitalized births for
                       -44-

-------
denominators, and different gestational cohorts for spontaneous



abortions and births occurring in the same calendar period).



       Major points which illustrate methodologic deficiencies



in the treatment and interpretation of the available data



include: estimates of the total amount of dioxin released



ranged from 650 g (Reggiani 1977) to 11 kg (Whiteside), to



130 kg (Nature 11/28/76); estimates of exposure per person


                   2                                  2
varied from 29 ug/m  (Tuchman-Duplessis) to 5,620 ug/m



(Reggiani 1977); exposure was characterized by geographic



zones, but reproductive data were gathered by geographic



districts raising questions whether the zones were contiguous



with the districts; spontaneous abortion rates were grouped



in 6-month intervals, but congenital malformation rates for



1976 were grouped in 12-month intervals which could have



masked an effect expected to be relatively acute or with a



2-3 month lag period; and the rates listed as "totals" for



the two groups of districts in Table 13 (in Reggiani  1977)



appear to be averages of the district  rates and as such are



invalid and cannot be interpreted; the  lack of chromosomal



abnormalities in the products of  therapeutic abortions is



overemphasized since dioxin could conceivably produce a



teratogenic effect without producing a  concomitant mutagenic



effect; and the wide interspecies variation seen in lethality



studies should not automatically  be applied to teratogenic



effects because it is known that  very  low doses are teratogenic



in the rat (e.g., 0.01 ug/kg) and dioxin doses which  caused



                       -45-

-------
teratogenic effects  in  rhesus  monkeys  were  apparently  as  low




as 2.5, 50, and 500  nanogr atns/kg.




       Suggestive  indications  of  a  possible  teratogenic




effect in humans,  from  the  available data,  include:  the




congenital malformation rate  increased by 570%  (about




7-fold) between 1976 and  the  first  five  months  of  1977




(Table 14, 0.13 to 0.87 per  100  live births)  (in Reggiani




1977).  The birth  rate  dropped "sharply" following  the




explosion (Whiteside) and cows aborted and  produced  malformed




offspring following  the explosion.  This lowered fertility




could be evidence  of increased teratogenic  risk; a  local




doctor noted a "marked  increase"  in convulsions among




infants.  (convulsions  could be delayed  effects of  neuro-




toxicity in utero).




       (b)  Vietnam




       A large amount of TCDD-contaminated  herbicides




were used in Vietnam during 1962-1971.   Possible health




effects have been  reported upon retrospectively by  groups




entering Vietnam.  Tung  et al. charged  that  2,4,5-T  was




responsible for much of the Down's  Syndrome  seen in  [South]




Vietnam. Crummer was quoted by Honoroff  as  having  observed




high incidences of children with Down's  Syndrome.   Tung et




al.  also noted a very significant increase  in the Hanoi




hospitals in hepatic carcinomas in  the period 1962-1968




[1790/7911 cancer cases (10%), compared  to  159/5492  (2.9%)




for  the period 1955-1961].




                         -46-

-------
        It  should  be  remembered  that  most  of  the  accidents
 reported here  were retrospective  accounts.   In the  cases
 of Seveso  and  Vietnam,  reporting  was (and still  is)  at
 best piecemeal.   The exposed  populations  contained  numbers
 of highly  mobile  persons  who  could not  be accounted  for
 adequately.
     (3)   Exposure Analysis
        (a)  General  Considerations
        There are  two components to any  pesticide-related
 risk: (1)  the  toxicological properties  of a  chemical,
 and (2) exposure  to  the chemical. The risk assessment is a
 summation  of the  conclusions  in each of these areas. A
 highly  toxic chemical may pose high  risk  even if exposure
 is low; conversely,  a compound of low to  moderate toxicity
 may pose high  risks  if exposure is high.
        Estimating probable exposure  is  difficult for a
 number of  reasons.   While it  would be inappropriate  to
 attempt a definitive discussion of these  problems here, it
 is useful  to note a  few examples.  First, empirical data on
 exposure is less available than is toxicology data.  Second,
 there are a number of exposure pathways which require
 consideration  (e.g.,   inhalation, dermal absorption,  ingestion
of food residues, and ingestion of water  residues).
Third,  the inherent  complexities of  the dynamics of a
chemical's movement  through the environment create formidable
obstacles to describing any given exposure pathway.  For
                       -47-

-------
example, the chemical may behave differently in various



media depending upon a number of environmental factors which



can vary at any one application site.  Thus, even when some



empirical data on a given route of exposure is available,



there are often uncertainties concerning the applicability



of the data to situations involving conditions which vary



from those which obtained at the study site.



       The inherent difficulties of exposure assessment



always create a troublesome problem for decision makers.



These problems are of great concern in situations involving



chemicals which appear to pose risks even at very low levels



of exposure.  As discussed above, the TCDD contaminant in



2,4,5-T and silvex is clearly such a chemical. For example,



TCDD is carcinogenic in rats at doses as low as 1 ppb and



fetotoxic in mice at doses as low as 0.01 mg/kg/day.



       Moreover, the complexities of exposure assessment



are also amplified in situations involving persistent



chemicals.  This is because the length of time a chemical



persists in the environment can increase the opportunities



for movement of the chemical and confound attempts to



eliminate pathways as pathways of concern.  Time increases



the possibilities of variation in environmental factors



affecting chemical mobility.



       The environmental persistence of 2,4,5-T and silvex



is relatively short due to physical, chemical, and biological



degradation processes.  On the other hand, the contaminant



                       -48-

-------
TCDD has a much longer persistence in soil and is known to
bioaccumulate in fish (Matsumura and Benezet, 1973; Kearney
et al., 1973).
       Generally, exposure assessments involve attempts at
modeling the likely exposure potential through several
pathways which are identified as pathways of principal
concern.  The exposure assessment typically will involve
attempts to describe the movement of the chemical from the
site of application to persons potentially at risk, using
such empirical data as are available on the presence of the
chemical at various intermediate points in the critical
path.  Conservative assumptions based upon such things as
knowledge about the behavior of similar chemicals, typical
environmental conditions affecting the use site, and
the like, are used to bridge inevitable gaps in the empirical
data. The objective, however, is a simple one: to obtain a
qualitative and (if possible) quantitative description of
the likelihood that a given chemical will move from where
it is applied to a given group of potentially exposed
individuals.
       Since 2,4,5-T first surfaced as a subject of regula-
tory concern, determining potential exposure has been
the critical issue on the risk side of the regulatory
equation. Uncertainties about exposure resulted in suspension
of regulatory action in 1974, and the launching of an
ambitious project to generate exposure data (the "Dioxin
                       -49-

-------
Implementation Plan" or "DIP").  Primarily  because  of  great

difficulties encountered in developing  analytical methodologiei

with sufficient sensitivity to measure  the  extremely  low

levels of TCDD which are of biological  concern,  the progress

of the DIP has been disappointing. To date,  it has  yielded

only fragmentary information.

       In my judgment, the  information  which  has  recently

come to my attention as a result of  the Alsea study consti-

tutes a dramatic and troubling new point  of departure

for analysis of TCDD exposure concerns.   As indicated  above,

these data show a striking  relationship between  2,4,5-T  use

and increased incidences of spontaneous abortions among

women residing in the use area.  As  further developed  above,

this effect is an effect which one would  have predicted  as  a

likely outcome of human exposure, based upon  a body of

animal data of almost unprecedented  conelusiveness.  The

Alsea study, to be sure, contained no data  showing  actual

exposure.   However, concern  for the health of humans  who

may be exposed to TCDD, and therefore to  2,4,5-T  or silvex

contaminated with TCDD, is heightened because scientists have

not demonstrated that there is a level  of exposure  that  has

no adverse effects in humans.—   Thus,  in the face  of  the

highly significant relationship which the study  showed,  and
jj[/  A committe of the National Research  Council  of  Canada
recently agreed with the authors  of  the  World  Health  Organiza-
tion's monograph on TCDD that "for TCDD  a  no-effect  level
for man could not be established"  (NRCC  1978).

                          -50-

-------
the animal data, I conclude  it  is  reasonable and in the

public interest to assume  that  the women in Alsea study were
                *#/
exposed to TCDD.	

       Moreover, I also  conclude  that  it is prudent to

assume that individuals  who  frequent  or live in areas where

2,4,5-T or silvex are  used may  be  exposed to TCDD in ways

and under conditions which may  cause  these individuals to be

exposed in ways qualitatively similar  to those experienced

by the Study area women.

       As developed below, I find  that silvex use patterns

likely to cause exposure  opportunities similar to the

exposure experienced by  the  Study  area women are the forestry,

rights-of-way, pasture,  home and  garden, commercial/ornamental

turf, and aquatic weed control/ditch  bank uses of silvex.

The Agency has identified  pesticide applicators and persons

involved in pesticide  application  support activities, and

persons living in or frequenting  areas of silvex use as the

principal groups of individuals who may be exposed as a

result of these uses of  silvex.
**/  I have found  it  prudent  to suspend because data from
the Alsea Epidemiological  Study indicates that women experi-
encing adverse reproductive  effects may have been exposed to
2,4,5-T. Information  of  this  kind concerning a chemical's
effects on human populations  is rarely available.  Before
the Alsea Study was completed,  Agency scientists developed
preliminary exposure  analyses for 2,4,5-T based on use
information, assumptions,  and modeling.  Since I have
information of adverse human  effects correlating with the
use of 2,4,5-T, I  have chosen to rely on this correlation as
a basis for regulatory action,  rather than on exposure
analyses based exclusively on use information and modeling.
                           -51-

-------
       (b)  The Alsea Study Area
       (i)  Description of Area
       The Alsea Study Area comprises approximately
1,600 square miles of Oregon's forested Coastal Range centered
around the "Alsea basin," an area of approximately 400
square miles.  It is bounded on the west by approximately
70 miles of the Pacific Coast and extends  inland for distances
ranging from 10 to 35 miles. The Study area includes all but
the northern and southern reaches of the Suislaw National
Forest.  Numerous commercially owned and Bureau of Land
Management forested acreages are interspersed throughout
this region. Mountain elevations of approximately 1,000 feet
are not uncommon; peak elevation is slightly more than 4,000
feet.  The principal rivers are the Siletz, Alsa, Yaquina
and the Suislaw.  Eastern fringes of the area drain eastward
into the Willamette Valley.  Maximum runoff is reached
generally during the winter months as the  result of storms
off the Pacific occurring usually as rain.
       The Study area is predominantly rural.  The four
largest towns have a total population of 14,450.  All
other towns/villages have populations of less than 1,700.
Alsea has a population of 400 (1970 census).  In addition,
many residences are scattered througout the forest areas.
All of the nine women who were idenitified in the first
phase of the investigation resided, at the time of pregnancy,
in rural residences located within 12 miles of Alsea.
                       -52-

-------
       (ii)   Use Pattern
       2,4,5-T is applied to the forests in the Alsea
area almost  exclusively by helicopter for control of undesir-
able vegetation such  as red alder, vine maple, salmonberry,
and thimbleberry. In general, the compound is used in the
spring (March, April, or May) with a second application
made, if  needed, in middle to late summer (July and/or
August).   Over the six-year study period, 10,000 pounds of
2,4,5-T was  distributed over a total area of approximately
7,000 acres.  The usual practice was to treat any particular
site approximately once every five years.  However, contiguous
stands could be treated in succeeding years.  The spray
program spans only a few days' time, with the duration
depending on the number of acres to be treated and the
weather conditions.
       To avoid contamination of water sources prior to
1978, the general application policy was to avoid spraying
near homes and to provide for a single swath of 30 to
60 feet on each side of any major stream.  In September
1978, the Oregon Forest Practices Act created guidelines
which prohibited spraying within 500 feet of an inhabited
residence or within 200 feet on either side of streams with
fish and/or ones that are used for domestic water supplies.
However,  drift and runoff could contaminate surface waters.
                       -53-

-------
       (iii) Population Exposed  to  the Herbicide




       Population of the Alsea Region  is  clustered  in




several small towns; there  are also  isolated  homes  and




farmsteads in the forest area.   Other  groups  which  may  be




traversing the forests of the Alsea  Region  include  workers




engaged in forest management, incidental  travelers,  hikers,




students, surveyors, and delivery persons.




       (iv) Modes of Exposure




       The major method of  dispensing  2,4,5-T in  the




Alsea Forest Region is by helicopters.  Although  the




Oregon Forest Practices Act prohibits  spraying  near  homes




or streams, there appears a likelihood that residents and




travelers of the Alsea Region might  be directly exposed  to




2,4,5-T during periods of application  as  a  result of drift.




Drift from a helicopter flying over  a  forest  canopy  can




produce drift of the herbicidal  spray  at  significant




distances from the path of  the aircraft.  Residents  or




travelers in the path of the spray might  be doused  with  the




pesticide spray.




       Exposure to the population from drift  and  direct




contact is by the dermal (exposed skin) and inhalation




routes.  Resident populations may also incur  exposure to




2,4,5-T and TCDD subsequent to application.   Waterborne




residues are a possible route of exposure;  other  possible






                          -54-

-------
exposure routes include  fish, wildlife,  and  other  foods

produced or found in the  area.   The  fact that  TCDD is

somewhat persistent and  bioaccumulat ive  may  enhance exposure

possibilities.  Furthermore,  pesticide  mixers,  loaders,

applicators, and other workers  may be exposed  to the pesticide.

       ( c)   Comparison Between  Presumed Exposure in The
            Al sea Study  Area  and Possible Exposure in
                  U s eS
       The Alsea Study  shows  a  significant correlation

between the use of  2,4,5-T  in the Alsea area and increased

incidence of spontaneous  abortions within approximately two

months after application.   The  Agency believes that it is

prudent to assume that  the  women studied were exposed to

2,4,5-T.  While the Agency  cannot determine the actual

routes of exposure,  information about how 2,4,5-T is applied,

population densities,  and proximity of Study area residents

to spray areas provides a basis for making assumptions about

possible chances for exposure.

       That 2,4,5-T was applied by helicopter rather than by

ground application  methods  in Alsea, enhanced the potential

for exposure to 2,4,5-T from drift.  Aerial application is a

principal method for applying 2,4,5-T and silvex.  Most of

the phenoxy herbicides applied in forests and on rights-of-

way are applied aerially.  In contrast, in pastures, applica-

tion  of 2,4,5-T and silvex usually is by  spot treatment with

knapsack spraying  equipment. This method, causing less spray

distribution than  aerial application, lessens potential

exposure from  drift.

                        -54a-

-------
       Alsea inhabitants live in towns  and  residences




scattered throughout forests in which 2,4,5-T was  applied.




Effects occurred even though application  near residences




and streams was prohibited.  The Study  area women  who




experienced spontaneous abortions were  residents of  the




area.  Their exposure to 2,4,5-T or TCDD  may have  occurred




either while they were at home or while they were  in nearby




forest areas. Bystanders, workers engaged in forest  management,




people visiting the forests for recreational purposes, and
                       -54b-

-------
others would have exposure  potential  similar to the exposure




potential of the Study  area women away from their homes.



Because TCDD persists  in  the environment, such non-residents



may have been exposed  to  2,4,5-T and  TCDD during or for some



unknown length of time  after application had occurred.



       The Study area  women may have  been exposed to



2,4,5-T or TCDD through ingestion of  drinking water,  fish,



and wildlife.  Residents  are more likely to be exposed



through this route  than infrequent visitors to the  spray



area. Frequent visitors or  workers in the area would  have



exposure potential  similar  to that of residents.  All other



forest areas in which  2,4,5-T or silvex  is used  are most


                                     */
obviously similar to  the  Study area.—



       The use of silvex  to maintain rights-of-way  involves



exposure potential  similar  to the exposure potential



of the Study area women:  residents of the application area




and workers  and visitors  who frequent the area may  be




exposed.



       The Agency estimates that a considerable  number  of




people may be  exposed  to silvex  and TCDD as  a result  of the



use of  silvex  in  non-urban  areas to maintain  rights-of-way.



Rights-of-way  uses  include highways, railway  lines,  electric



power  lines,  and  pipelines.  A principal method  of  applying
~*1Commercialforests are defined  as  those  lands  not

withdrawn for non-timber purposes which  are  capable of

growing  20 cubic feet of wood per year  of  desirable species.



                            -55-

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silvex is by aircraft, which was the method of application

in the Alsea, Oregon area.

       The population that is most likely to be exposed are

people who live in the path of the spray or in the area of

drift.—   A large potential exposure group would be

comprised of people living along railroad tracks and along

highways.  Other groups that may be exposed are those that

live in forests or plains along power lines and pipelines.

The residents may be exposed to TCDD through the diet for

longer periods of time due to low levels of TCDD contam-

ination in water and food.  An additional potentially

exposed group are people working in, or traveling through,

the treated area.

       Exposure from the use of silvex in pastures is
                                       ** /
likely to be lower than the Study area.—7   Pastures
V  Factors which affect drift include wind direction and
velocity, turbulence, relative humidity and air temperature,
atmospheric stability, pesticide formulation, application
equipment, and spray volume.  For purposes of this analysis,
the Agency conservatively estimated possible pesticide drift
at 1/2 mile.  The Agency notes, however, that pesticides
could drift farther depending on the variables listed above.
Some pesticide drift has been reported as far as 22 miles
from target (EPA DRAFT: "Report to Congress/Study - ULV," p.
95).  In addition, this same draft report estimates that
percent of pesticide drift over 1,000 feet from the target
variously ranges from a low of 10% to a high of 90%.
**/  Pasture is defined as land producing forage for animal
consumption, harvested by grazing, which has annual or more
frequent cultivation, seeding, fertilization, irrigation,
pesticide application, and other similar practices applied to
it.  Fencerows enclosing pastures are included as part of
the pasture.

                       -56-

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are likely to be near  farmhouses  and  small  towns.  The

populations which may  be  exposed  to  silvex  include farm

families, other rural  residents,  and  workers  in rural

occupations. The predominant  method  of application for

controlling brush in pastures  is  spot treatment with knapsack

spraying equipment. The distribution  of silvex from this

technique is lower than thai,  from forestry  and right s-o f-way

use, because this technique  produces  only short-range  drift.

Indirect exposure due  to  residues in food is  possible.

       Generally, persons involved in applying pesticides

have greater exposure  to  the  chemicals than do residents of

the area in which the  pesticides  are used.   There is no

reason to believe that this  would not be true of  silvex.

Therefore,  the Agency  is  concerned about potential exposure

to  pilots,  ground spray  crews, mixers and loaders, and

flaggers, all of whom  are exposed to silvex in the applica-

             */
tion process .—

       For  aerial application, the ground crew, including

mixers and  loaders  of  the aircraft,  is the group  with  the

highest  potential  for  exposure by both dermal  and inhalation
T]In  response  to the 2,4,5-T RPAR, the American Paper
Ynstitute  and  the National Forest Products Association
recently  submitted a detailed study of applicator ex-
posure  to  2,4,5-T during both aerial and ground appli-
cations (2,4,5-T RPAR submission #1023H - 30000/26).
The  results  of this study indicate that workers who handled
the  pesticide  concentrate had the highest exposure, followed
by knapsack  sprayer applicators, mist blower  drivers,
helicopter pilots, supervisors, and flagmen.

                          -57-

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routes, because they handle the concentrated formulations.
The flaggers on the ground are exposed mainly by drift of
the diluted spray deposited on their exposed skin, and to a
lesser degree by inhalation.  The pilots are expected to be
exposed to smaller amounts of silvex by dermal and inhalation
routes because they sit in the enclosed cabin of the helicopter
while applying the diluted herbicide spray.  For the ground
application techniques, the applicators and mixers are the
workers running exposure risk.  Inhalation exposure may be
more significant when fine mist sprayers (for example,
foliar treatment are used) in contrast to stump treatment
spraying with a coarse spray.  The reason for this is that
smaller spray droplets are more readily absorbed through the
lungs.
       The exposure to silvex of persons using the pesti-
cide for home and garden use may be higher than the ex-
posure of most other groups potentially exposed.  The
exposure from home and garden use would appear to be
greater than the exposure from forestry use in areas
such as Alsea.  Furthermore, home and garden exposure
to owners/applicators may be greater than the exposure
of persons involved in commercial application of silvex
or 2,4,5-T since home users are not likely to wear
appropriate protective clothing or to take adequate
precautionary measures.
                       -58-

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       Several home and garden application techniques



have inherent exposure potential.  Hose-end diluters



probably have a high potential for dermal exposure to



both applicators and bystanders because of the long range of



the spray arising from these devices.  The coarseness of the



spray, however, probably precludes any significant inhalation



exposure or drift away from the site of treatment.



       Another possibility for exposure from home and



garden use occurs during the dilution of liquid concentrates



of silvex. The concentrate may spill or splash onto the



exposed skin of the user. Additional exposure to householders



may occur during spraying, mixing, and cleanup of equipment.



It is unfortunately true that householders may not exercise



appropriate caution, and may, for example, spray upwind,



thus receiving an unduly high amount of drift on face,



hands, and other unprotected parts of the body.  Other



sources of potential applicator exposure include splashing



and low-distance drift droplets from tank sprayers, aerosol



containers, and dust particle drift from granular application.



       Persons who are bystanders could also receive exposure



to silvex by accidental splashing or drift, or low-level



drift droplets and/or dust particles from granular formulations,



       Some home and garden applications of silvex are



made by lawn care professionals, who work much more extensively



with this herbicide than would a single homeowner.  These



professionals, however, are likely to exercise more care



                       -59-

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during the use of pesticide chemicals, and  thus  avoid




spills or substantial dermal exposure.




       Silvex is also used for weed control  in sites  such




as public parks, golf courses, athletic  fields,  institutional




lawns, and sod farms.  These uses  are  similar to the  home




and garden uses described above.   The  most  exposed group  is




likely to be the applicators.  Another group of  persons




who may be exposed are bystanders, sports enthusiasts,




residents of the institutions, etc.  The routes  of exposure




for all these groups are likely to be  chiefly dermal.  The




applicators are exposed not only by applying the herbicide,




but also by mixing and diluting the concentrate.  Bystanders




and people who enter treated areas will  incur less exposure




than applicators, unless they get  aceidentially  splashed  or




sprayed.




       Silvex is used to control plants  in  waters used for




recreation and in farm ponds.  Thus, the general population




may be exposed from this use of silvex by swimming, engaging




in water skiing, drinking treated  waters, or eating fish




caught in waters where silvex has  been applied.




       The applicators involved in this  use  of silvex




are professional or staff persons  engaged by authorities




responsible for maintaining clean  waterways.  Applicators




apply the material from boats.  Applicator  exposure is




likely to be greater if the applicator uses  a mechanical




sprayer than if the applicator pours the formulation






                       -60-

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directly onto the water,  unless  spillage results acci-

dentally from pouring.  The  fine  mist  dispensed by the

mechanical sprayer could  be  deposited on unprotected skin or

could be inhaled.

     C.   Determination  of Benefits

       The Agency has evaluated  the economic effects of

suspension of non-crop  uses  of  silvex for a period of two

years until completion  of the  decision whether these uses

                   */
should be cancelled—  .  The  co  nsideration of economic

impacts  stemming from a suspension  is limited to a two-year

period because the maximum  projected  length of a cancellatin

proceeding would be tgwo  years.   A  suspension order remains

in effect only during a cancellation  proceeding.  Thus, only

the impacts which would arise  during  this period would be at

issue in a suspension.   Any  impacts which would be caused by

a suspension, but which would  be felt after this period, are
               **/
also considered—  .
^_l The emergency  suspension order will take effect immediately
upon issuance of  this  Notice and remain in effect during
any subsequent emergency  suspension hearings.  At the
conclusion of the  hearings, a decision will be made whether
to continue or remove  the suspension order during the
ensuing cancellation  proceedings.  Economic impacts are
therefore separately  evaluated for the 3 1/2 month period
allocated for an  emergency suspension proceeding as well as
for the two years  which  may be required for a cancellation
proceeding.
**/ The Agency's  analysis is based on information from a
"rTumber of sources  including RPAR rebuttal comments received
by the Agency from registrants, users and other parties
during the RPAR process;  and the USDA-States-EPA 2,4,5-T
RPAR Assessment Report (February 15, 1979) as well as other
relevant data.  Although  the 2,4,5-T Report attributes a
role to EPA, the  final report has neither been completely
reviewed nor approved  by  EPA.  Therefore, although the
Agency has relied  on  some portions of the report, it
cannot and does not wish  to adopt all portions of the report
as reflecting the  Agency  position on matters discussed
herein.

                         -61-

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       The non-crop  uses  of silvex include those it has in




common with major  uses  of 2,4,5-T (forestry, pasture, and




rights-of-way), as well as  home and garden, and commercial/




ornamental turf and  aquatic weed contro1/ditch bank.




(Rangeland is  not  included).   In addition, the Agency




has evaluated  the  economic effects of emergency  suspension




of these uses  - i.e.,  the consequences of silvex not being




available for  these  uses  for the duration of an  emergency




suspension (3  1/2  months).




       Domestic usage  of  silvex is estimated to  be  about 2.8




to 3.3 million pounds.   Commercial/ ornamental turf  and home




and garden uses of  silvex are the largest volume uses,




comprising more than 50%  of domestic usage.  Aquatic weed




control/ditch  bank  usage  accounts for about 8% of  annual
                         -61a-

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usage.  Other uses, primarily pasture,  account  for  about  10%




of use.  The proposed suspended uses  of  silvex  account  for




about two-thirds of its annual usage.   The major  remaining




uses are rangeland, rice, and sugarcane.




       Economic impacts of suspending  forestry, pasture,




rights-of-way,  and non-crop usage of  silvex during  a  two-year




period, generally were estimated by assuming  all  registered




alternatives are available, except 2,4,5-T which  is also




subject to suspension.  The analysis  generally  provides




qualitative estimates of impacts since  data are not available




to support precise quantitative estimates.




       Economic impacts during a suspension would depend




upon the treatment options actually selected  by users.  For




many, use of silvex during 1979 and 1980  would  be optional




(i.e., could be delayed to a later year).  Other  users might




choose to use alternatives immediately.




       The Agency's analysis indicates  that a two-year




suspension of silvex non-crop uses would  not  significantly




affect U.S. production or prices of any  commodities or




services in affected sectors.  Economic  impacts of  the




suspension would be minor in most cases,  even at  the  local/




regional level.




       The major economic significance  of suspending  silvex




is that it would not be available for  more extensive  use  on




forest and pasture sites as a 2,4,5-T  substitute.   Silvex






                          -62-

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usage on those sites could  increase  significantly in the




event of suspension of  2,4,5-T  on  those sites because silvex




is an economic alternative  for  2,4,5-T in many instances.




       Economic impacts  during  the 3 1/2 month emergency




suspension proceeding would  be  negligible.   Any silvex




treatments scheduled for this  period could be delayed




without affecting the efficacy  of  the treatments or cost to




users .




       The economic impacts  of  suspending each individual




non-crop use of silvex,  including  those it has in common




with 2,4,5-T, are discussed  below.




     (1)  Forestry




       Silvex now appear to  be  used on a rather limited




scale in forestry.  Bureaus  of  the  U.S. Department of Interior




(USDI)  and the U.S. Forest  Service  (USFS) have used  silvex




in the past year.   A USDI policy memorandum  (June 12, 1970)




prohibited use of 2,4,5-T and  restricted the use of  picloram,




but did not include  silvex  on  either  prohibited or  restricted




lists.   Nonetheless, USDI use  of  silvex appears to  have  been




discontinued during  1977.  However, as much  as 30,000 acres




(up to 50,000 pounds  a.e.)  were treated annually by  BLM




during the early  to mid-1970's.   Forest Service use  has




declined and currently  involves very  small quantities (less




than 500 pounds  a.e.)   Some silvex  could be  used by  non-




govermental users,  but  no documentation of such usage is




available.






                          -63-

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        Silvex can be used at either  or  both  of  two stages in

 the  production—  of conifers:   (1) preparing  sites for

 reforestation and (2) releasing young trees  from hardwood

 competition.   Each operation is undertaken once  in the  50
jj[_/ Silvex is  sometimes used for other forestry herbicide
operations, including  rehabilitation or species conversion,
fuel break maintenance,  and timber stand improvement.  The
major forestry  uses  of silvex are site preparation and
release, which  are  the focus of this analysis.
                             -63a-

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year cycle of a softwood stand. Silvex,  as well  as  other




chemical and non-chemical control methods, may be  used




individually or in combination  for  site  preparation and




release.




       Use of silvex for site preparation  is  not critical




although it is cost effective.  Several  other chemicals,  as




well as non-chemical methods, are also  effective for site




preparation. Picloram and 2,4-D, sometimes combined,  are




the most effective substitute chemicals.   2,4-D  costs  less




than silvex but controls a more limited  spectrum of weeds




and often has to be used more frequently,  thus resulting  in




higher costs than a single silvex treatment.  In  the past,




2,4,5-T has been preferred to silvex  for  site preparation




because it controls a wider variety of  hardwoods.




       Because the release (weeding)  operation is  conducted




after the seedling trees are in place,  a  selective  herbicide




which will not harm the seedlings is  preferred.  This  is




particularly true for pine; silvex  provides  control of many




hardwood competitors; however it also can  damage pine




seedlings.  As a consequence of its lack  of  selectivity




silvex has not been extensively used  for  release treatments.




Its use has been limited to non-pine  conifer  stands in the




west and fir-spruce stands in the Northeast.






                        -64-

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       In both agencies,  costs have already been  increased




by $20-$200/acre due  to  the use of release methods  other




than silvex and 2,4,5-T.   Site preparation continues  at cost




increases of $10-$40/acre using picloram/2,4-D  and  other




chemicals on those  areas  which require herbicide  controls.




Release costs in Washington and Oregon are  $20-$50/acre  for




substitute chemical  control.   Manual control, when  used,




increases costs about  $60-$1OO/acre more than silvex.




       USDI is presently  reviewing the department policy




regarding pesticide  use  and is considering adding silvex  to




the list of prohibited chemicals.  USDI decisions regarding




1979 plans for use  of  silvex  are pending EPA decisions, and




alternative plans have been developed for  vegetation  management




wi thout silvex.




       The suspension  of  forestry uses of  silvex  for  either




3 1/2 months or two  years would not have any significant




current economic impact  because the chemical is not now in




use.  The prinicipal  potential users, USDI and  USFS,  have




already discontinued  use.  The only significance  of the
                          -65-

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silvex suspension for forestry use is that it would not be
available as a substitute for 2,4,5-T.
     (3)  Rights-of-Way
       Silvex is used to control woody and herbaceous
plants on vegetated rights-of-way (railroad, highway,
electric transmission, and pipeline) which could hamper
the use of the system (weeds encroaching on highways)
threaten the system's equipment, and/or interfere with
inspection and maintenance of the system.
       Manual and mechanical methods are the most common
control practices on rights-of-way acreage.  Combining
chemical and non-chemical control methods is common as is
use of herbicide combinations to enhance their effectiveness
and expand the spectrum of plants to be controlled in a
single application.
       Chemical treatment uses a variety of chemicals,
including phenoxy herbicides.  Usage of silvex for rights-of-
way vegetation control is minimal, e.g., less than 2% of
rights-of-way firms use it.
       If silvex is not available, users can be expected to
treat with other herbicides.  Dichlorprop, 2,4-D, and
picloram mixed with 2,4-D are all cheaper than silvex.
Several alternatives control more species than silvex, and
equivalent control may be achievable at less cost. No
significant negative economic impacts could be expected from
a two-year suspension of this use.  Economic impacts during
a 3 1/2 month emergency suspension would also be  insignificant,
                       -66-

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     (3)   Pasture
       The phenoxy herbicides (2,4-Df 2,4,5-T and silvex)
are registered for the control of many woody and herbaceous
weeds on pasture.  Silvex is generally more effective
for woody plant control than 2,4-D but controls a
narrower spectrum of weeds than 2,4,5-T.
       Current silvex usage on range and pasture is apparently
small enough that no reliable estimates of use have become
available.  No more than 500,000 pounds active ingredient are
used annually.  Most of this amount is probably used on
range, although states such as Minnesota, Virginia, and New
England states recommend silvex for control of some weeds in
pasture.   In Massachusetts, about 9,000 pasture acres are
treated with silvex annually, but pasture usage in other
states has not been reported.  Silvex was not considered by
the 2,4,5-T Assessment Team to be an alternative to 2,4,5-T
for pasture or fencerow applications because of its relatively
narrow spectrum of control.
       Brush control with herbicides on pasture and along
pasture fencerows is usually accomplished by spot treatment.
Presumably, silvex is also applied in this manner when it is
used.
       Since other chemicals, e.g., picloram, dicamba,
2,4-D, are generally preferred to silvex for pasture use,
farmers who currently use silvex would presumably adopt
these alternative herbicides.
                       -67-

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       No yield or production effects would occur during a
two year suspension.  For individual farmers using silvex,
alternative controls might be more expensive.  If so, these
farmers' income will be reduced by the amount of the cost-of-
control increase.  Such effects will be nominal in most
cases. There would be no impacts on consumer prices or the
general economy.  Agricultural income may be reduced by an
immeasurably small amount.  In view of the limited economic
impacts from a two year suspension period, economic impacts
during the 3 1/2 months required for an emergency suspension
proceeding would be of no significance.
     (4)  Commercial/Ornamental Turf
       Ornamental turf includes golf courses, athletic
fields, parks, playgrounds, highway turf, and turf farms for
purposes of this analysis. Of these, golf courses are the
major consumer of herbicides used to control broadleaf turf
weeds.
       Precise current estimates of silvex use on turf are
not available but annual usage could be as high as 2 million
pounds active ingredient.  Combinations of 2,4-D, MCPP, and
dicamba are readily available and effective treatments for
clover and chickweed which are major broadleaf weed pests.
In golf courses, these chemicals are common control treatments
for these pests.  Data on other turf uses are not available.
       Without silvex, users will shift to combinations
of 2,4-D, MCPP, and dicamba to control broadleaf weed
                       -68-

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pests. Treatment  costs with silvex, silvex combinations,




alternatives,  and combinations of alternatives vary depend-




ing on region,  target weed species, application  rates,




formulations,  and package size.  Material costs  for silvex




and dicaraba  are  comparable at $7.50 per acre.  Silvex




combined with  2,4-D is about $1 per acre more expensive  than




MCPP, MCPP + 2,4-D, and 2,4-D + dicamba.  Combinations of




MCPP/2,4-D/dicamba are about $4.50 to $14.50 per  acre more




expensive than  silvex/2,4-D mixtures.  On the average,




alternatives are  about $3.50 per acre more expensive than




silvex and silvex mixtures.




       For individual turf managers, these control cost




increases will  be nominal.  Golf courses, for example,




spend $80-$90  per acre for turf maintenance which includes




chemical fertilizers, fungicides, herbicides, and insecti-




cides, but excludes irrigation, mowing, and other direct




costs.  Thus,  increased broadleaf weed control costs of




$3.50 per acre  could increase maintenance costs by about 4




percent.  Economic impacts during a two year suspension




would not be adverse to the overall commercial/ornamental




turf sector.No  economic impacts are anticipated during the 3




1/2 month emergency suspension proceeding.  Most  treatments




scheduled during  this period could be delayed without




causing significant control problems or increasing user




costs.




                           -69-

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     (5)  Home and Garden




       Most of the herbicides used by  the homeowner  in  the




U.S. are for control of broadleaf weeds  and  grass  pests  in




lawns.  At least three-fourths of U.S. homeowners  do  not  use




any herbicides.  Liquids are more popular than  granular




forms in terms of quantities used and  dollar  sales.   Several




hundred thousand pounds of silvex are  used annually  on  home




lawns.




       Silvex is most commonly used with 2,4-D, MCPP,  and




dicamba to control species resistant to  2,4-D (i.e.,




chickweed, clover, spurge and henbit).   Based on  label




claims and state recommendations, combinations  of  2,4-D,




MCPP, and dicamba would be equally effective.




       Homeowners would shift to products containing  2,4-D,




MCPP, and dicamba in the event of a silvex suspension.




These alternatives are effective, readily available,




and comparably priced.  Thus, homeowner  adjustments  for




either 3 1/2 months and/or 2 years suspension would  be




nominal.




     (6)  Aquatic Weed Control/Ditch Bank




       Aquatic weeds are a nuisance in water  bodies  used  for




recreation and in farm ponds used for  watering  livestock.




Major users of herbicides for aquatic  weed control  are




government and private recreational organizations  and




farmers.  Government purchases of aquatic herbicides  account




for nearly half of annual sales. Private recreation  organiza-




tions account for more than a third and  farmers the  remainder.




                           -70-

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       Silvex and  a  mixture  of silvex and endothall are




registered for use  in  aquatic  weed control in ponds, lakes,




marshes, and shorelines.   Silvex controls submerged, emerged,




and floating types  of  flowering plants.  Essentially all




weeds controlled by  silvex are sensitive to various other




major aquatic herbicides,  including 2,4-D, diquat, endothall,




and dichlobenil.   Silvex,  2,4-D, and diquat exhibit similar




herbicidal activities  in  aquatic sites.




       Silvex is also  applied  to drainage ditch banks and




canal levees.  Particular  target weeds include the phyrea-




tophytes, various  exotics, and other woody plants  such as




rubber and willow  trees  (Loeser, 1975; Baker, 1975).




There appear to be  no  viable alternative chemical  controls




for some plant pests such  as the phreatophytes and some




exotics (Loeser, 1975).   However, there are many  other




chemicals registered that  are  effective on many species




found along ditch  banks  and canal levees.




       For most uses of  silvex, 6 pounds a.i./acre per




foot are applied in  late  spring to early summer.   Approximately




240,000 pounds of  silvex  were  used in 1972 for water




management purposes  (von  Rumker et al. 1974).  This estimate




includes silvex used in  static water  areas such as recrea-




tional sites, reservoirs,  settling ponds, and ditch banks.




At an assumed application  rate of 6 pounds of silvex per




acre, approximately  60 thousand acres of static water and




ditch banks were treated  in 1972.






                             -71-

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       Consumption of silvex for weed  control  in  stationary

water areas is not critical due to  the  availability  of

effective chemical alternatives including  2,4-D,  diquat  and

dichlobenil.  Also, the Argentine  flea  beetle  is  an  effective

biological control of alligator weed when  used  in an IPM

program with silvex or 2,4-D.

       Economic effects of  suspending  aquatic/ditch  bank

users of silvex for 3 1/2 months or 2  years  would be nominal

because effective, economical alternatives  are  available.

There would not be a significant economic  burden  on  users.

V.  PROCEDURAL MATTERS

       This order directs the emergency  suspension of the

forestry, rights-of-way, pasture, home  and  garden, aquatic

weed control/ditch bank, and commercial/ornamental turf  uses

of silvex.  Registrants affected by emergency  suspension

actions may request an expedited hearing before  the  Agency.

This section explains how to request an  expedited hearing,

the consequences of requesting or not  requesting  an  expedited

hearing, and the procedures which govern an  expedited

hearing in the event one is requested.

     A.  Procedures for Requesting  a Hearing

       (1)  Who May Request a Hearing  and  When  the Request
            Should Be Made

       Registrants of silvex products  registered  for the

forestry, pasture, rights-of-way, home  and  garden, aquatic

weed control/ditch bank, or commercial/ornamental turf  uses


                          -72-

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of  silvex  may  request a hearing on these  specific  registered

uses of  silvex within five days after receipt  of  this

opinion  and  order.

        (2)   How to  Request a Hearing

       Registrants  who request a hearing  must  follow

the Agency's Rules  of Practice Governing  Hearings  (40  CFR,

Part 164).   These  procedures specify, among other  things:

(1) that all requests for a hearing must  be accompanied  by

objections that  are specific for each use  for  which a

hearing  is requested [40 CFR 164.121(a) and 164.123(b)]  and

(2) that all requests must be filed with  the Office of the

Hearing  Clerk  within the applicable five  (5) days  [40  CFR

164.l21(a)].   Failure to comply with these requirements  will

automatically  result in denial of the, request  for  a hearing.

       Requests  for hearings must be submitted  to:

                   Hearing Clerk (A-110)
                   U.S.  Environmental Protection Agency
                   401 M Street, S.W.
                   Washington, D.C. 20460

     B.  Consequences of Filing a Hearing Request

       Under FIFRA  Section 6(c)(3) the emergency  suspension

order becomes  effective immediately and,  unless stayed,

continues  in effect  until completion of the expedited

hearing  and  issuance of a final order of  suspension.  The

statute  provides that where an administrative hearing is

requested, the  emergency order is subject to District Court

review on  the  emergency finding.   The final suspension order

                             -73-

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issued by the Administrator after a hearing may keep the
suspension in effect, modify it, or terminate it.  A final
suspension order issued following a hearing is then reviewable
in the Court of Appeals.
       The statute provides that if a hearing is requested
on the Administrator's emergency suspension actions regarding
silvex before the end of the five-day notice period, the
hearing stage is to begin within five days after receipt
of the request, unless the registrant and the Agency agree
that it shall begin at a later time. No party, other than
the registrant and the Agency, is to participate, except
that any person adversely affected may file briefs within
the time allowed by the Agency's rule.  Hearings on emergency
suspension, like hearings on ordinary suspension, are
subject to the provisions of subchapters II of Title
5 of the United States Code, except that the presiding
officer need not be a certified hearing examiner.  The
presiding officer has ten days from the conclusion of the
presentation of evidence to submit recommendations to the
Administrator, who in turn has seven days to issue a
final order on the issue of suspension.
     C.  Consequences of Not Filing a Hearing Request
       Under the statutory scheme, if there is no request
for a hearing on the Administrator's suspension actions
within the five-day notice period, the emergency suspension
order becomes a final suspension order, which remains in
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effect until the conclusion of the cancellation proceedings,
unless modified or vacated sooner (40 CFR 164.130).  Court
review of an emergency suspension order, including the
special review before the District Court discussed in Part
II, is available only if an administrative hearing has been
requested within the applicable five-day period [FIFRA
Section 6(c)(2), 6(c)(3)].
     D.  Supplementary Procedures
       EPA's Rules of Practice for expedited hearings are
set forth at 40 CFR Part 164, Subpart C.  I do not know if a
hearing will be requested on these suspensions.  If it is,
however, I am establishing the following procedures to
supplement the existing  regulations  in governing its
conduct.
       1.  A deadline is being established for the comple-
tion of all hearing procedures and the rendering of a
recommended decision under 40 CFR 164.121(j).  That dead-
line is 90 calendar days from the first prehearing con-
ference, which shall be  held  in  accordance with the time
requirements described below.
       2.  I am naming certain EPA employees  to serve as  a
hearing panel  in  any hearing  arising out of this notice  (see
Appendix A).
       I am naming  certain additional persons  to be available
to provide technical advice  and  staff support  to the hearing
panel  (see also Appendix A).   If questions  arise at the
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hearing which persons in this category  are  uniquely  qualified




to assess, they may be called on to serve on  the  panel




either in addition to, or in substitution for,  the  three




panel members named above.




       The panel will conduct the hearing and  submit  a




recommended decision to me under 40 CFR  Section  164.121(j).




None of the persons named above is subject  in  the  normal




course of their duties to the supervision or  direction




of any employee or agent of EPA who is  a member  of  the




Agency trial staff named below.  See 5  U.S.C.  Section




554UH2).




       Since 5 U.S.C. Section 554(d)(l)  provides  that




those presiding at adjudicatory hearings may  not  "con-




sult a person or party on a fact in issue [in  the  course




of preparing their decision] unless on  notice  and  opportunity




for all parties to participate," neither myself  nor  my




appellate staff will consult with the panel or its  supporting




staff on any matters involving this case from  the  date  of




notice until a recommended decision is  issued.   Members of




my appellate staff are listed in Appendix A.   We  will




conduct an independent review of the questions presented on




appeal of any recommended decision.  However,  in  doing  this




we will feel free to consult with the hearing  panel  and the




support panel, since they will have conducted  the  initial




proceedings and brought expert knowledge to evaluating  the




record.






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        The  following Agency bureaus or  divisions,  and

 ther  staffs,  are  designated to perform  all  investigative

 and prosecutorial functions in this case:   Office  of

 the Deputy  Administrator— , Office of Toxic  Substances,

 the Office  of General Counsel,

 and the  Office of Enforcement.

        From the  date of this notice until any  final decision,

 no member of  the  hearing panel, its support  staff, my

 appellate staff,  or myself, shall have  any  esx_  parte contact

 with  any trial staff employees, or any  other interested

 person  not  employed by EPA, on any of the issues  involved  in

 this  proceeding.   However,  persons interested  in  this  case

 should  feel  free  to contact any other EPA employee, including

 both  trial  staff  and persons not explicitly  named  as panel

 members or  assistants, with any questions they may have.

        3.   I  am  directing the hearing panel  to proceed as

 follows to  streamline proceedings in this case:

            a.  My findings  on imminent  hazard  and  emergency

 for suspended  uses  of silvex together with  supporting
^_/  The Deputy Administrator may properly be included in
the trial staff  since  the prohibitions of 5 U.S.C. Section
554(d) do not apply  to "the agency".  Her inclusion is
necessary if guidance  on general policy matters is to be
available to the  trial staff and, to free a high agency
official to talk  to  outside interested persons about the
questions involved without the constrains otherwise imposed
by the ex parte  provisions of the APA and the Government
in the Sunshine Act.   The Deputy Administrator will take
no part in the detailed work of preparing and presenting
the Agency's case.
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information are in my opinion and order, which is available

for inspection in the Office of the Hearing Clerk.  Additional

supporting information, including references cited in the

opinion and orders, is also available for inspection in

the Office of the Hearing Clerk.  Together these documents
                                            ** /
constitute the Agency record in this matter.—EPA has

also attempted to put this information in perspective

through a narrative summary and analysis.

           b.  The scheduling of any hearing, particularly

in its earlier stages, involves a balancing between the

need to conduct an expeditious hearing and a concern

that the hearing not proceed too far before the identity

of those registrants requesting a hearing is established.

In arranging for the first prehearing conference, I have

attempted to accommodate both interests.  The hearing

panel shall convene the first prehearing conference within

five days after receipt of the last request for a hearing

by a registrant or 15 days after the issuance of my

opinion and order, whichever comes earlier.  The 15-day

maximum should ensure that all registrants wishing to

participate in the hearing have been given ample time

to file a hearing request after receiving notification

of my suspension actions.


**/ Some of the documents in the record may be entitled
to confidential treatment under FIFRA Section 10, as amended.
Parties to the hearing may have access to such documents,
if appropriate protective arrangements are made.  See
also the footnote to this Order concerning confidentiality
of data in Section IV.A.(1)(a)(i).

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           c.  Within  ten  days from the first prehearing




conference, any  person requesting a hearing shall submit




focused written  comments  on  this opinion and order con-




sisting of a count erstatement  of proposed findings on




the issue of imminent  hazard presented by silvex  together




with supporting  information.  A narrative summary explaining




its bearing on the  case should also be included.




           d.  The  Agency  trial staff shall have  seven




days thereafter  to  file supplemental information  and




comment s.




           e.  Within  five calendar days from the




filing of any  supplemental information by the Agency




staff, the panel  shall convene a second prehearing




conference.  At  this  conference all parties shall




appear prepared  to  present arguments on the signfici-




ance and relevance  of  the  material already presented.




This prehearing  conference shall also hear all  requests




for oral presentation  of direct evidence and cross-




examination, and the  reasons  supporting them.   At  this




time each party  shall  present the names of witnesses




available  for  cross-examination on the matters  the




party  is putting into  issue.  The party may list




documents  (or  portions thereof) on which the potential




witness is  available   for cross-examination in  lieu




of  filing  a  formal witness  statement.







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           f.  Within  five days  after  the  prehearing




conference is over, the panel  shall  issue  a  hearing order




setting the schedule for oral  presentation of  witnesses and




cross-examinat ion.




           (1)  Requests for oral  presentation of direct




testimony shall be granted only  if it  is  demonstrated that




the testimony can be presented meaningfully  only in that




form; in all other cases, direct testimony shall be in




writ ing.




           (2)  Requests for cross-examination shall  be




granted only if all of the following showings  are made:




         i.  The  request concerns  factual  matters.   Cross-




examination will  not be granted  on matters of  policy




or law.




         ii.  The factual matters  are  legitimately  in




dispute in light  of the record.




         iii.  The factual matters are  material  to  the




decision to be made.




         iv.  Cross-examination  is the  most  efficient




way of resolving  the dispute over  these factual  matters (as




opposed to such alternatives as  production of  further




information, or informal conferences).




         v. There is a reasonable  expectation  that  cross-




examination will  resolve the issue of material  fact in a way




likely to influence the final  decision.




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           g.  The  testimonial  phase of the hearing shall




begin three days  after  issuance of the order setting the




hearing schedule.   At  the  hearing, the panel shall take an




active role in the  development  of the record through




questioning of witnesses  and  by issuing procedural orders




where necessary.




           h.  At  the  end  of  the initial testimonial




phase, the hearing  panel  may  permit the introduction of




additional information designed to rebut the contentions




made by opposing  parties.




           i.  The  panel  may  revise any of  the procedural




provisions of  this  notice  other than the overall 90-day




deadline  for rendering a  recommended decision, the time  for




which starts running after the first prehearing conference.




       A  discussion of some aspects of  these procedures




follows:




       (1)  Deadlines




       Deadlines  for completing proceedings  under  FIFRA




have  been twice  endorsed  by the National Academy  of  Sciences




[National Academy of Sciences, Decision Making in  the




Environmental  Protection  Agency,  Vol.  II,  p. 84 (1977);




National  Academy of Sciences,  Decision  Making  for  Regulating




Chemicals in  the Environment,  p.  30  (1975)].




       In addition, Congress has  demonstrated  a concern




for  speedy action where suspensions  based  on a potential




threat to human health are concerned.   It  has  required a




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 hearing  on  such  a  suspension to begin five days after it is

          */
 requested—  ,  and has  allowed ten and seven days respectively

 for  preparation  of  the  initial  and  final  decisions once the

 hearing  is  over  [FIFRA  Section  6(c)(2)].   FIFRA was amended

 in  1975  to  require  consultation by  EPA with the Department

 of Agriculture and  a  scientific advisory  panel  before taking

 action in many cases; suspensions based on human health

 grounds,  however, were  exempted from those requirements to

 allow speedy  action where  speedy action was desirable

 [121 Cong. Rec. H 9895-96  (daily ed.  Oct.  9,  1975); 121

 Cong. Rec. Section  19820-21  (daily  ed.  Nov. 12, 1975)].

       Deadlines for  completing the  hearing have been

 imposed  in prior suspensions.   See,  e.g.,  In  re: Vesicol

 Chemical  Co., et al.. 41 F.R.7552,  7553 (Feb.  19,  1976)

 [Notice  of Intent to  Suspend  Heptachlor and Chlordane],  and

jn re:   Dibromochloropropane, 42 FR  48915  (Sept. 26,  1977).

 [Notice  of intent to  suspend  and conditionally  suspend

registrations of pesticide products].   The requirements  set

 forth in  this order simply carry forward  that  practice.

       (2)  Use of a Panel

       Despite the need for  speedy action,  the  issues

involved  in suspension are complex. Under  the  statute,  a
*7Ido notregard the procedures set forth below  as
inconsistent with this directive.  What concerned Congress
was plainly that the hearing stage of Agency decision-
making begin promptly, not that  the oral hearing itself
start unconditionally in less than a week.  To  interpret
the law otherwise would forbid the use of such  accepted
aids to efficient decisions as prehearing conferences  in
precisely the cases where efficiency is most required.

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judgement of "imminent hazard" must be based on considera-



tion of costs and risks of all types [FIFRA Sections 2(1),



2(bb)]. Given the necessary time constraints and the prelimi-



nary nature of suspension as a remedy, factual certainty may



be elusive.  "[T]he function of the suspension decision



is to make a preliminary assessment of evidence, and probabi-



lities, not any ultimate resolution of difficult issues"



[Environmental Defense Fund, Inc. v. EPA, 510 F.2d. 1292,



1298 (D.C. Cir. 1975), quoting from Environmental Defense



Fund, Inc. v. EPA, 465 F.2d. 528, 537 (D.C. Cir. 1972)].



       Arriving at even such a preliminary assessment



can present formidable difficulties.  Considering risks,



questions can arise concerning the dispersion and persistance



of the pesticide in the environment and certain parts of



it, the conduct of animal feeding studies, the meaning



of those studies for human health, the validity of relevant



epidemiological studies, the reliability of using known



human exposure from one use pattern as a predictor of



potential human exposure in other use patterns, and finally



on what the upper and lower boundaries of any risks may



be and how firmly they are established.  Considering benefits,



questions can be raised about the extent of use, the



availability, practicality, and effectiveness of substitutes



both now and in the future, and the range of the probable



economic impacts of a temporary ban on the pesticide, or



some use of  it, in the light of all these factors.



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       The job will be easier and better performed, if
I am allowed to rely directly on the talents of EPA employees
with expert knowledge of the technical fields involved
and with the professional ability to assess problems arising
in them. I believe it is for this reason that Congress has
provided that those presiding over suspension hearings need
                        */
not be hearing examiners—'.
       (3)  Conduct of the Hearing
       Overuse of cross-examination and courtroom formali-
ties, I believe, has made many FIFRA proceedings far longer
than was consistent with any rational purpose.  The overwhelm-
ing bulk of legal analyses by those who have studied the
problem, and EPA's own experience demonstrate that scientific
and economic issues can be clarified by the exchange of
written material far more efficiently than through courtroom
hearings. I am directing that written submissions be used
here to focus the issues in an attempt to implement those
lessons.  At the same time,  particularly where Congress has
explicitly called for formal hearings, the accompanying
rights to reasonable cros.s-examination and oral presentation
must be preserved.
^J The fact that more than one person will preside is
of no legal significance.  Even when 5 U.S.C. Section
556 requires a hearing to be presided over by an examiner
(or a person representing the Agency), it also specifies
that "one or more" of those qualified may preside.
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       All three elements of these supplementary procedures



are meant to work together.  The use of a panel will ensure



that expert knowledge is indeed brought to the task of



making a decision. The provision for preliminary written



submissions will allow that panel to screen the issues and



narrow the formal part of the hearing down to those that



are legitimately in dispute and suited to adjudicatory



resolution. Finally, setting a schedule for decision will



help ensure that the potential gains in efficiency represen-



ted by the first two reforms >£re/realized/in practice.
         FEB 28  079
                         Admirtistritor
Dated:
                        -85-

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       APPENDIX A
HEARING PANEL

Charles Gregg, Chairperson
William Brungs
Robert Coughlin
TECHNICAL SUPPORT PANEL

Robert Chapman, M.D.
Neil Chernoff
Arnold Kuzmack
Dr. James Lichtenberg
ADMINISTRATIVE APPELLATE PANEL

Ronald L. McCallum
Charles R. Ford
Dr. Edwin H. Clark
Ms. Mary Ann Massey
Dr. Richard M. Dowd
Dr. Stephen J. Gage

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