Exhibit 10.35.6

STANDSTILL AGREEMENT

     THIS AGREEMENT  effective as provided  herein by and between  ENVIRONMENTAL
REMEDIATION HOLDING CORPORATION ("ERHC"), a Colorado  corporation,  with offices
at 1686 General  Mouton Avenue,  Lafayette,  LA 70508 and the Investors or their
permitted assigns whose names are included in Schedule A annexed hereto and made
a part hereof (collectively the "Investors" or individually, the "Investor").

     WHEREAS,  ERHC and the Investors  executed a Securities  Purchase Agreement
and Registration  Rights Agreement at three (3) closings in July and August 1998
under which ERHC issued its 8.0% convertible  notes due July 29, 2000, August 4,
2000 and August 19, 2000 (the  "Notes),  ERHC and J.P.  Carey  executed  Warrant
Agreements  for each of the three (3)  closings  (the  "WA")  under  which  ERHC
granted J.P. Carey warrants to purchase  ERHC's common stock with exercise dates
on or before July 28, 2003,  August 3, 2003 and August 18, 2003 (the "Warrants")
and  ERHC  agreed  to file a  Registration  Statement  with the  Securities  and
Exchange  Commission  ("SEC")  relative to the Notes and Warrants (the "SPA" and
"RRA" respectively) ; and

     WHEREAS,  ERHC has  executed  and its Board of  Directors  have  approved a
letter of intent  dated April 8, 1999 with ERHC  Investment  Group,  Inc.  which
requires certain consents from the Investors and amendments and modifications to
the SPA, WA, RRA the Notes and the Warrants, a copy of which letter of intent is
annexed hereto and made a part hereof as Exhibit A (the "Letter of Intent"); and

     WHEREAS,  the parties wish to confirm in writing  their  understanding  and
agreement regarding these matter.

     NOW THEREFORE in consideration of the mutual promises  contained herein and
for other good and valuable consideration, the receipt and adequacy of which are
hereby acknowledged, the parties agree as follows:

1.   Confidential   Information.   Investors'   consent   and   amendments   and
     modifications  to the SPA,  WA,  RRA,  Notes and Warrant as provided in the
     Letter of Intent are conditions  precedent to the Initial Closing.  This is
     due to the fact that the Notes and Warrants have certain  adjustments which
     may render it impossible for ERHC to issue the requisite  control  interest
     required  under the term of the Letter of  Intent.  The  matters  contained
     herein  and in the  Letter  of  Intent  are  confidential  information  not
     available  to the  public.  These  matters  will only be made public with a
     filing  by ERHC of a Form 8K  within  the time  required  from the  Initial
     Closing as defined in the Letter of Intent  (the  "Initial  Closing"),  the
     date on which an 8K event takes place. Accordingly, the Investors expressly
     agree not to disclose,  use or trade on this information either directly or
     indirectly  in any  manner  until such time as the Form 8K  reporting  this
     Letter of Intent is filed with the SEC.







2.   Amendments  and  Modifications.  The SPA provides  that upon the vote of 66
     2/3% of the Investors under such agreement, any of the terms and conditions
     of the SPA, WA, RRA, the Notes and the Warrants may be amended or modified,
     provided such amendment or  modification  is in writing and executed by not
     less  than 66 2/3% of the  Investors.  In such  event,  the  amendment  and
     modification  will  be  effective  as to all of the  Investors  under  such
     agreement. In the event that 66 2/3% of the Investors under the SPA execute
     this Agreement,  and except as otherwise  specifically provided for herein,
     from the date of the  Initial  Closing  under the Letter of  Intent,  it is
     agreed that the following terms and conditions are amended and modified:

     A.   The  adjustment  provisions to the terms of the Notes or Warrants,  if
          any, contained in the SPA are deleted.

     B.   The Notes are amended and modified as follows:

          1.   The provision for payment of interest contained in paragraph 1(b)
               is amended to permit, in addition to the other methods of payment
               contained  therein,  for the  payment of  interest in the form of
               shares  in  common  stock in an  amount  equal to the  amount  of
               interest due divided by the Conversion Price.

          2.   In addition to the  amendment to paragraph  1(b),  the  following
               will be  added  to such  paragraph:  "Notwithstanding  any  other
               provision  contained in this paragraph  1(b),  interest is waived
               from the date of the Initial Closing and thereafter until October
               15, 1999.

          3.   The  provisions for voluntary  conversion  contained in paragraph
               5(a) is amended to permit,  in addition to conversion of all or a
               portion of the Notes, for the conversion of outstanding  interest
               and penalties,  if any, into Common Stock at the time a voluntary
               conversion of principal is made for the amount of interest due on
               the Notes.

          4.   The conversion  formula in paragraph 5(c) of the Notes is deleted
               in its  entirety  and the  following  substituted  in its  place,
               "Subject  to the  Adjustments  from time to time as  provided  in
               Section 5(d) below, the "Conversion Price" shall mean $0.25.

          5.   The  adjustments  of  Conversion  Price in paragraph  5(d) of the
               Notes are  deleted  in their  entirety  and the text set forth in
               Exhibit B annexed  hereto and made a part hereof  substituted  in
               its place:

     C.   The Warrant Agreements are amended and modified as follows:







          1.   The  antidilution  provisions  in  paragraph  7  of  the  Warrant
               Agreements  are deleted in their  entirety and the text set forth
               in Exhibit C substituted in its place.

     D.   The RRA is amended and modified to add the following subparagraph:

          1.   ARTICLE 2, Paragraph  2.2(a) - "(vii)  Notwithstanding  any other
               provision contained in this subparagraph (a) , the penalty and/or
               liquidated damage set forth in this paragraph for failing to have
               ERHC's Registration Statement become effective during a specified
               period of time is waived from the date of the Initial Closing and
               thereafter until October 15, 1999."

     E.   In  addition  to  the  foregoing  amendments  and  modifications,  the
          Investors consent and agree to the following additional terms:

          1.   From the date of the Initial Closing and thereafter until October
               15,  1999 (i) not to convert  all or any part of the Notes,  (ii)
               not to declare a default  or seek  acceleration  of any  payments
               under the Notes, (iii) not to commence any collections actions or
               proceedings under the Notes, (iv) not to commence any foreclosure
               or bankruptcy actions under the Notes, and (v) not to declare any
               Event of Default or commence any  arbitration  actions  under the
               SPA, WA, RRA, Notes or Warrants.

          2.   From the date of execution of this Agreement, to waive all rights
               under any  adjustments,  antidilution  provisions  or  preemptive
               rights previously granted in the SPA, WA, Notes, Warrants, or RRA
               or provided by these amendments and modifications (i) relative to
               the  transaction  contemplated  in the  Letter  of Intent or (ii)
               relative to any settlement with Procura Financial entered into by
               the Company upon  commercially  reasonable  terms to complete the
               assignment of all rights, title and interest in Sao Tome in favor
               of the Company.

          3.   Through the Initial Closing, to accept shares of Common Stock for
               all accrued and unpaid  interest and penalties on the Notes as of
               the Initial  Closing,  which shares shall be delivered within ten
               (10) days of the Closing Date.

          4.   From the date of execution of this Agreement and thereafter until
               October 15, 1999,  to vote with the Company in the event that any
               third  party,  other  than  each of the  other  note and  warrant
               holders listed as a Selling Shareholder in Amendment No. 3 to the
               Form S- 1  filed  with  the  SEC,  commences  any  bankruptcy  or
               foreclosure   action   against   the   Company   or  any  of  its
               subsidiaries.







3.   Effects  of No Closing  under the  Letter of  Intent.  In the event that no
     Closing as defined in the Letter of Intent (the  "Closing")  occurs  within
     ninety  (90) days from the date of the  Initial  Closing,  the  amendments,
     modifications  and  consents in paragraph 2 above shall be null and void ab
     initio.

4.   ERHC Representations and Warranties.  ERHC represents and warrants that the
     amendments,  modifications  and  consents  set  forth  in  paragraph  2 are
     substantially similar to the amendments,  modifications and consents sought
     from each of the  other  convertible  note and  warrant  holders  listed as
     Selling  Shareholders in the Amendment No. 3 to the Form S-1 filed with the
     SEC and differ only in those matters  which are specific to any  particular
     note or warrant transaction listed therein.

5.   Effect upon Other Terms and Conditions.  Notwithstanding the amendments and
     modifications  contained  herein,  it is  expressly  agreed by the  parties
     hereto that all other terms, conditions and provisions of the SPA, WA, RRA,
     Notes and Warrants remain in full force and effect.

6.   Ratification.  The Investors ratify the acts of and hold harmless the Board
     of Directors and Officers for all actions taken by them in compliance  with
     the  interpretations  of any  court  of  competent  jurisdiction  as to the
     application  of the  Business  Judgment  Rule from  inception  through  the
     Initial Closing Date.

7.   Intended  Beneficiaries.  ERHC  and  ERHC  Investment  Group  Inc.  are the
     intended  beneficiaries of this Agreement.  In the event of any breach, the
     parties and the intended  beneficiaries  of this  Agreement  shall have all
     remedies  available  at  law or in  equity  including  the  right  to  seek
     injunctive relief.

8.   Effective Date. This Agreement shall be effective and binding upon ERHC and
     the  Investors  set  forth  in  Schedule  A from  the  date  ERHC  receives
     signatures  from not less than 66 2/3% of such  Investors as to paragraph 2
     and from the date of execution by each  Investor as to such  Investor as to
     the other provisions of this Agreement.

9.   Binding Obligations.  The obligations of the parties set forth herein shall
     be binding upon and inure to the benefit of each party's heirs,  executors,
     administrators, beneficiaries, transferees, successors and assigns.

10.  Governing Law,  Jurisdiction and Venue. The governing law, jurisdiction and
     venue set forth in the SPA,  WA,  Notes,  Warrants  and RRA shall remain in
     full force and effect.

11.  Counterparts.  This  Agreement may be executed in one or more  counterpart,
     each of which when taken  together shall  represent one binding  agreement.
     Delivery  of an  executed  counterpart  hereof via  telecopier  shall be as
     effective as delivery of a manually executed counterpart hereof.






     IN  WITNESS  WHEREOF,  each  party set  their  hand and seal  effective  as
provided herein.

                         ENVIRONMENTAL   REMEDIATION   HOLDING   CORPORATION
                         By:  /s/  JAMES  A.GRIFFIN
                           ------------------------
                        James A. Griffin, Secretary

                         INVESTOR:

Execution Date: April 22, 1999       Atlantis Capital Fund Ltd
                                     By: /s/ MARK VALENTINE
                                       --------------------
                                      Signature and Title
                                     Print Name: Mark Valentine
                                     Print Title: Agent
                                     Standstill on: $100,000

Execution Date:      , 1999          By: /s/ SANDRO GRIMALDI
                                       ---------------------
                                       Signature and Title
                                     Print Name: Sandro Grimaldi

Execution Date:       , 1999         By: /s/ MOHAMMED KHLIFA
                                       ---------------------
                                         Signature and Title
                                     Print Name: Mohammed Khlifa
                                     for $460,000 of unconverted debenture

[Signature Page July/August 1998 Funding]






                                   SCHEDULE A





           ATLANTIS CAPITOL FUND, LTD

           ATLAS CAPITAL FUND, LTD.

           OSCAR BRITO

           CORRELLUS INTERNATIONAL, LTD.

           SANDRO GRIMALDI

           HOLDEN HOLDING, LTD.

           PRIMECAP MANAGEMENT GROUP, LTD.

           MOHAMMED KHALIFA

           GPS AMERICA FUND, LTD.

           J. P. CAREY, INC.









                                    EXHIBIT B

Adjustments of Conversion  Price.  The  Conversion  Price in effect from time to
time shall be,  subject to adjustment in accordance  with the provisions of this
Section .

     (i) Adjustments for Stock Splits and Combinations.  If the Company shall at
any time or from time to time after the Issuance  Date,  effect a stock split of
the  outstanding  Common  Stock,  the  applicable  Conversion  Price  in  effect
immediately prior to the stock split shall be proportionately  decreased. If the
Company shall at any time or from time to time after the Issuance Date,  combine
the  outstanding  shares of Common Stock,  the  applicable  Conversion  Price in
effect immediately prior to the combination shall be proportionately  increased.
Any  adjustments  under  this  Section  (i) shall be  effective  at the close of
business on the date the stock split or combination occurs.

     (ii) Adjustments for Certain  Dividends and  Distributions.  If the Company
shall at any time or from time after the Issuance  Date,  make or issue or set a
record date for the determination of holders of Common Stock entitled to receive
a dividend or other distribution payable in shares of Common Stock, then, and in
each event, the applicable  Conversion Price in effect immediately prior to such
event shall be decreased as of the time of such issuance or, in the event such a
record  date shall have been  fixed,  as of the close of business on such record
date, by multiplying,  as applicable,  the applicable  Conversion  Price then in
effect by a fraction;

          (A) the  numerator  of which  shall be the  total  number of shares of
Common  Stock  issued  and  outstanding  immediately  prior  to the time of such
issuance or the close of business on such record date; and

          (B) the  denominator  of which shall be the total  number of shares of
Common  Stock  issued  and  outstanding  immediately  prior  to the time of such
issuance  or the close of business on such record date plus the number of shares
of Common Stock issuable in payment of such dividend or distribution.

     (iii)  Adjustment  for Other  Dividends and  Distributions.  If the Company
shall at any time or from time to time after the Issuance Date, make or issue or
set a record date for the  determination  of holders of Common Stock entitled to
receive a dividend or other distribution  payable in other than shares of Common
Stock, then, and in each event, an appropriate  revision to the Conversion Price
shall be made and  provision  shall be made (by  adjustments  of the  Conversion
Price  or  otherwise)  so that  the  holder  of this  Note  shall  receive  upon
conversions  thereof,  in  addition  to the  number of  shares  of Common  Stock
receivable  thereon,  the number of  securities  of the Company which they would
have received had this Note been converted into Common Stock on the date of such
event and had  thereafter,  during the period from the date of such event to and
including the  Conversion  Date,  retained such  securities  (together  with any
distributions  payable  thereon during such period),  giving  application to all
adjustments  called for during such period under this Section (iii) with respect
to the rights of the holders of the Note.

     (iv) Adjustments for  Reclassification,  Exchange or  Substitution.  If the
Common Stock  issuable upon  conversion of this Note at any time or from time to
time after the Issuance Date shall be  changed  into the same or  different






number of shares of any class or classes of stock,  whether by reclassification,
exchange,  substitution  or  otherwise  (other  than by way of a stock  split or
combination of shares or stock dividends  provided for in Sections (i), (ii) and
(iii), or a reorganization,  merger,  consolidation,  or sale of assets provided
for in Section (v)),  then, and in each event,  an  appropriate  revision to the
Conversion  Price shall by made and provisions  shall be made (by adjustments of
the  Conversion  Price of  otherwise) so that the holder of this Note shall have
the right  thereafter to convert such Note into the kind and amount of shares of
stock  and  other  securities   receivable  upon   reclassification,   exchange,
substitution or other change, by holders of the number of shares of Common Stock
into  which  such Note  might  have  been  converted  immediately  prior to such
reclassification, exchange, substitution or other change, all subject to further
adjustment as provided herein.

     (v)  Adjustments  for  Reorganization,  Merger,  Consolidation  or Sales of
Assets.  If at any time or from time to time after the Issuance Date there shall
be a capital  reorganization  of the Company (other than by way of a stock split
or combination  of shares or stock  dividends or  distributions  provided for in
Section (i), (ii) and (iii), or a reclassification,  exchange or substitution of
shares  provided  for in  Section  (iv)),  or a merger or  consolidation  of the
Company with or into another  corporation,  or the sale of all or  substantially
all of the Company's properties or assets to any other person, then as a part of
such reorganization,  merger, consolidation, or sale, an appropriate revision to
the Conversion  Price shall be made and provision  shall be made (by adjustments
of the Conversion Price or otherwise) so that the holder of this Note shall have
the right  thereafter to convert this Note into the kind and amount of shares of
stock  and  other  securities  or  property  of the  Company  or  any  successor
corporation resulting from such reorganization,  merger, consolidation, or sale,
to which a holder of Common Stock  deliverable  upon  conversion  of such shares
would have been entitled upon such  reorganization,  merger,  consolidation,  or
sale,  to which a holder of Common Stock  deliverable  upon  conversion  of such
shares would have been entitled upon such reorganization, merger, consolidation,
or  sale.  In any  such  case,  appropriate  adjustment  shall  be  made  in the
application  of the provisions of this Section (v) with respect to the rights of
the holders of this Note after the  reorganization,  merger,  consolidation,  or
sale to the  end  that  the  provisions  of  this  Section  (v)  (including  any
adjustment in the applicable  Conversion  Ratio then in effect and the number of
shares of stock or other  securities  deliverable  upon conversion of this Note)
shall be applied  after that event in as nearly an  equivalent  manner as may be
practicable.







                                    EXHIBIT C

Antidilution Provision. The Exercise Price in effect from time to time shall be,
subject to adjustment in accordance with the provisions of this Section .

     (a) Adjustments for Stock Splits and Combinations.  If the Company shall at
any time or from time to time after the date hereof, effect a stock split of the
outstanding  Common Stock, the applicable  Exercise Price in effect  immediately
prior to the stock  split  shall be  proportionately  decreased.  If the Company
shall at any  time or from  time to time  after  the date  hereof,  combine  the
outstanding  shares of Common Stock,  the  applicable  Exercise  Price in effect
immediately prior to the combination  shall be  proportionately  increased.  Any
adjustments  under this  Section (a) shall be effective at the close of business
on the date the stock split or combination occurs.

     (b) Adjustments  for Certain  Dividends and  Distributions.  If the Company
shall at any time or from  time  after the date  hereof,  make or issue or set a
record date for the determination of holders of Common Stock entitled to receive
a dividend or other distribution payable in shares of Common Stock, then, and in
each event, the applicable  Exercise Price in effect  immediately  prior to such
event shall be decreased as of the time of such issuance or, in the event such a
record  date shall have been  fixed,  as of the close of business on such record
date, by  multiplying,  as  applicable,  the  applicable  Exercise Price then in
effect by a fraction;

          (i) the  numerator  of which  shall be the  total  number of shares of
Common  Stock  issued  and  outstanding  immediately  prior  to the time of such
issuance or the close of business on such record date; and

          (ii) the  denominator  of which shall be the total number of shares of
Common  Stock  issued  and  outstanding  immediately  prior  to the time of such
issuance  or the close of business on such record date plus the number of shares
of Common Stock issuable in payment of such dividend or distribution.

     (c) Adjustment for Other Dividends and Distributions.  If the Company shall
at any time or from time to time after the date  hereof,  make or issue or set a
record date for the determination of holders of Common Stock entitled to receive
a dividend or other  distribution  payable in other than shares of Common Stock,
then, and in each event, an appropriate  revision to the Exercise Price shall be
made and  provision  shall  be made (by  adjustments  of the  Exercise  Price or
otherwise)  so that the  holder  of this Note  shall  receive  upon  conversions
thereof, in addition to the number of shares of Common Stock receivable thereon,
the number of  securities of the Company which they would have received had this
Note  been  converted  into  Common  Stock  on the  date of such  event  and had
thereafter,  during the period from the date of such event to and  including the
date hereof,  retained such securities (together with any distributions  payable
thereon during such period),  giving  application to all adjustments  called for
during such  period  under this  Section  (c) with  respect to the rights of the
holders of the Warrant.

     (d)  Adjustments for  Reclassification,  Exchange or  Substitution.  If the
Common Stock  issuable upon  conversion of this Warrant at any time or from time
to time after the date hereof shall be changed into the same or different number
of shares of any class or classes of stock, whether by reclassification,






exchange,  substitution  or  otherwise  (other  than by way of a stock  split or
combination of shares or stock  dividends  provided for in Sections (a), (b) and
(c), or a reorganization,  merger, consolidation, or sale of assets provided for
in Section (e), then, and in each event, an appropriate revision to the Exercise
Price shall by made and provisions shall be made (by adjustments of the Exercise
Price of  otherwise)  so that the  holder of this  Warrant  shall have the right
thereafter  to convert  such Warrant into the kind and amount of shares of stock
and other securities receivable upon reclassification, exchange, substitution or
other change, by holders of the number of shares of Common Stock into which such
Warrant might have been converted  immediately  prior to such  reclassification,
exchange,  substitution  or other change,  all subject to further  adjustment as
provided herein.

     (e)  Adjustments  for  Reorganization,  Merger,  Consolidation  or Sales of
Assets. If at any time or from time to time after the date hereof there shall be
a capital  reorganization  of the Company (other than by way of a stock split or
combination  of shares  or stock  dividends  or  distributions  provided  for in
Section (a), (b), and (c), or a  reclassification,  exchange or  substitution of
shares provided for in Section (d), or a merger or  consolidation of the Company
with or into another corporation, or the sale of all or substantially all of the
Company's  properties  or  assets to any  other  person,  then as a part of such
reorganization,  merger, consolidation,  or sale, an appropriate revision to the
Exercise Price shall be made and provision  shall be made (by adjustments of the
Exercise  Price or  otherwise) so that the holder of this Warrant shall have the
right  thereafter  to convert this Warrant into the kind and amount of shares of
stock  and  other  securities  or  property  of the  Company  or  any  successor
corporation resulting from such reorganization,  merger, consolidation, or sale,
to which a holder of Common Stock  deliverable  upon  conversion  of such shares
would have been entitled upon such  reorganization,  merger,  consolidation,  or
sale,  to which a holder of Common Stock  deliverable  upon  conversion  of such
shares would have been entitled upon such reorganization, merger, consolidation,
or  sale.  In any  such  case,  appropriate  adjustment  shall  be  made  in the
application  of the provisions of this Section (e) with respect to the rights of
the holders of this Warrant after the reorganization,  merger, consolidation, or
sale to the  end  that  the  provisions  of  this  Section  (e)  (including  any
adjustment in the applicable  conversion  ratio then in effect and the number of
shares of stock or other securities deliverable upon conversion of this Warrant)
shall be applied  after that event in as nearly an  equivalent  manner as may be
practicable.