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                                                                  EXHIBIT 4.6(b)




                           MASTER CORPORATE GUARANTY


                 Pioneer Americas Acquisition Corp., a Delaware corporation
(the "Borrower") has requested that Bank of America Illinois ("BAI") and the
other Lenders now or hereafter party to the Loan Agreement (as defined below)
(the "Lenders"), provide certain financial accommodations to the Borrower.  As
one of the conditions to providing financing to the Borrower, BAI, as agent for
itself and each of the other Lenders ("Agent"), has required that each of the
subsidiaries of Borrower set forth on Exhibit A attached hereto (collectively,
"Guarantors", and individually a "Guarantor") guaranty the obligations of the
Borrower to Agent and the Lenders.

                 For value received and in consideration of any loan, advance,
or financial accommodation of any kind whatsoever heretofore, now or hereafter
made, given or granted to the Borrower by Agent and the Lenders, each Guarantor
jointly and severally unconditionally guaranties the full and prompt payment
when due, whether at maturity or earlier, by reason of acceleration or
otherwise, and at all times thereafter, of all "Liabilities" as such term is
defined in that certain Loan and Security Agreement among the Borrower, Agent
and the Lenders of even date herewith (the "Loan Agreement") (all such
Liabilities being hereinafter referred to as "Borrower's Obligations").  Each
Guarantor further agrees to pay all costs and expenses including, without
limitation, all court costs and attorneys' and paralegals' fees and expenses
paid or incurred by Agent or the Lenders in endeavoring to collect all or any
part of Borrower's Obligations from, or in prosecuting any action against, any
Guarantor or any other guarantor of all or any part of Borrower's Obligations.

                 Each Guarantor hereby agrees that its obligations under this
Master Corporate Guaranty shall be unconditional, irrespective of (i) the
validity or enforceability of Borrower's Obligations or any part thereof, or of
any promissory note or other document evidencing all or any part of Borrower's
Obligations, (ii) the absence of any attempt to collect Borrower's Obligations
from the Borrower, any Guarantor or any other guarantor, or other action to
enforce the same, (iii) the waiver or consent by Agent or the Lenders with
respect to any provision of any instrument evidencing Borrower's Obligations,
or any part thereof, or any other agreement now or hereafter executed by the
Borrower and delivered to Agent and the Lenders, (iv) failure by Agent to take
any steps to perfect and maintain its security interest in, or to preserve its
rights to, any security or collateral for Borrower's Obligations, for its
benefit or the ratable benefit of the Lenders, (v) Agent's election, in any
proceeding instituted under Chapter 11 of Title 11 of the United States Code
(11 U.S.C. Section 101 et seq.), as amended (the "Bankruptcy Code") of the
application of Section 1111(b)(2) of the Bankruptcy Code, (vi) any borrowing or
grant of a security interest by the Borrower as debtor-in- possession, under
Section 364 of the Bankruptcy Code, (vii) the disallowance, under Section 502
of the Bankruptcy Code, of all or any portion of Agent and the Lenders'
claim(s) for repayment of Borrower's Obligations, or (viii) any other
circumstance which might otherwise constitute a legal or equitable discharge or
defense of the Borrower or a guarantor.
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                 Until the Payment Liabilities have been repaid in full and
there is no further commitment to make Loans or issue Letters of Credit under
the Loan Agreement, no payment made by or for the account or benefit of any
Guarantor (including without limitation (i) a payment made by the Borrower in
respect of Borrower's Obligations, (ii) a payment made by any Guarantor in
respect of Borrower's Obligations, (iii) a payment made by any person under any
other guaranty of Borrower's Obligations or (iv) a payment made by means of
set-off or other application of funds by Agent or the Lenders) pursuant to this
Master Corporate Guaranty shall entitle any Guarantor, by subrogation or
otherwise, to any payment by the Borrower or from or out of any property of the
Borrower, and no Guarantor may exercise any right or remedy against the
Borrower or any property of the Borrower including, without limitation, any
right of contribution or reimbursement by reason of any performance by such
Guarantor under this Master Corporate Guaranty.  The provisions of this
paragraph shall survive the termination of this Master Corporate Guaranty or
the release or discharge of any and all Guarantors from liability hereunder.
Each Guarantor and Agent hereby agree that the Borrower is and shall be a third
party beneficiary of the provisions of this paragraph.

                 Each Guarantor hereby waives diligence, presentment, demand of
payment, filing of claims with a court in the event of receivership or
bankruptcy of the Borrower, protest or notice with respect to Borrower's
Obligations and all demands whatsoever, and covenants that this Master
Corporate Guaranty will not be discharged, except by complete and irrevocable
payment and performance of the obligations and liabilities contained herein.
No notice to any party, including any Guarantor, shall be required for Agent to
make demand hereunder.  Such demand shall constitute a mature and liquidated
claim against each Guarantor.  Upon any Event of Default (as defined in the
Loan Agreement) by the Borrower as provided in any instrument or document
evidencing all or any part of Borrower's Obligations, including without
limitation the Loan Agreement, Agent may, at its sole election, proceed
directly and at once, without notice, against any Guarantor, or all of the
Guarantors, to collect and recover the full amount or any portion of Borrower's
Obligations, without first proceeding against the Borrower, any other
Guarantor, or any other person, firm, or corporation, or against any security
or collateral for Borrower's Obligations.  Agent shall have the exclusive right
to determine the application of payments and credits, if any, from any
Guarantor, the Borrower or from any other person, firm or corporation, on
account of Borrower's Obligations or of any other liability of any Guarantor to
Agent and the Lenders.

                 Agent and the Lenders are hereby authorized, without notice or
demand and without affecting the liability of any Guarantor hereunder, to, from
time to time, (i) renew, extend, accelerate or otherwise change the time for
payment of, or other terms relating to, Borrower's Obligations or otherwise
modify, amend or change the terms of any promissory note or other agreement,
document or instrument now or hereafter executed by the Borrower and delivered
to Agent and the Lenders; (ii) accept partial payments on Borrower's
Obligations; (iii) take and hold security or collateral for the payment of
Borrower's Obligations guaranteed hereby, or for the payment of this Master
Corporate Guaranty, or for the payment of any other guaranties or Borrower's
Obligations or other liabilities of the Borrower, and exchange,


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enforce, waive and release any such security or collateral; (iv) apply such
security or collateral and direct the order or manner of sale thereof as in its
sole discretion it may determine; and (v) settle, release, compromise, collect
or otherwise liquidate Borrower's Obligations and any security or collateral
therefor in any manner, without affecting or impairing the obligations of any
Guarantor hereunder.

                 At any time after maturity of Borrower's Obligations, Agent
may, in its sole discretion, without notice to any Guarantor and regardless of
the acceptance of any security or collateral for the payment hereof,
appropriate and apply toward payments of Borrower's Obligations (i) any
indebtedness due or to become due from Agent or any of the Lenders to any
Guarantor, and (ii) any moneys, credits or other property belonging to any
Guarantor, at any time held by or coming into the possession of Agent or any of
the Lenders or any affiliates thereof, whether for deposit or otherwise.

                 Each Guarantor hereby assumes responsibility for keeping
itself informed of the financial condition of the Borrower, the other
Guarantors, and any and all endorsers and/or other guarantors of any instrument
or document evidencing all or any part of Borrower's Obligations and of all
other circumstances bearing upon the risk of nonpayment of Borrower's
Obligations or any part thereof that diligent inquiry would reveal and each
Guarantor hereby agrees that Agent shall have no duty to advise any Guarantor
of information known to Agent or the Lenders regarding such condition or any
such circumstances.  Each Guarantor hereby acknowledges familiarity with the
Borrower's financial condition and has not relied on any statements by Agent or
the Lenders in obtaining such information.  In the event Agent, in its sole
discretion, undertakes at any time or from time to time to provide any such
information to any Guarantor, Agent shall be under no obligation (i) to
undertake any investigation not a part of its regular business routine, (ii) to
disclose any information which, pursuant to accepted or reasonable commercial
finance practices, Agent wishes to maintain confidential or (iii) to make any
other or future disclosures of such information or any other information to
such Guarantor.

                 Notwithstanding any provision of this Master Corporate
Guaranty to the contrary, it is intended that this Master Corporate Guaranty,
and any liens and security interests granted by any Guarantor to secure this
Master Corporate Guaranty, not constitute a "Fraudulent Conveyance" (as defined
below) by any Guarantor.  Consequently, each Guarantor agrees that if this
Master Corporate Guaranty, or any liens or security interests securing this
Master Corporate Guaranty, would, but for the application of this sentence,
constitute a Fraudulent Conveyance by it, this Master Corporate Guaranty and
each such lien and security interest shall be valid and enforceable only to the
maximum extent that would not cause this Master Corporate Guaranty or such lien
or security interest to constitute a Fraudulent Conveyance by such Guarantor,
and this Master Corporate Guaranty shall automatically be deemed to have been
amended accordingly at all relevant times.  For purposes hereof, "Fraudulent
Conveyance" means a fraudulent conveyance under Section 548 of the Bankruptcy
Code or a fraudulent conveyance or fraudulent transfer under the provisions of
any applicable





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fraudulent conveyance or fraudulent transfer law or similar law of any state,
nation or other governmental unit, as in effect from time to time.

                 Each Guarantor consents and agrees that Agent shall be under
no obligation to marshall any assets in favor of any Guarantor or against or in
payment of any or all of Borrower's Obligations.  Each Guarantor further agrees
that, to the extent that the Borrower makes a payment or payments to Agent, or
Agent receives any proceeds of collateral, for its benefit and the ratable
benefit of the Lenders, which payment or payments or any part thereof are
subsequently invalidated, declared to be fraudulent or preferential, set aside
and/or required to be repaid to the Borrower, its estate, trustee, receiver or
any other party, including without limitation any Guarantor, under any
bankruptcy law, state or federal law, common law or equitable cause, then to
the extent of such payment or repayment, Borrower's Obligations or the part
thereof which has been paid, reduced or satisfied by such amount shall be
reinstated and continued in full force and effect as of the date such initial
payment, reduction or satisfaction occurred and this Master Corporate Guaranty
shall continue to be in existence and in full force and effect, irrespective of
whether any evidence of indebtedness has been surrendered or canceled.

                 Each Guarantor also waives all setoffs and counterclaims and
all presentments, demands for performance, notices of nonperformance, protests,
notices of protest, notices of dishonor, and notices of acceptance of this
Master Corporate Guaranty.  Each Guarantor further waives all notices of the
existence, creation or incurring of new or additional indebtedness, arising
either from additional loans extended to the Borrower or otherwise, and also
waives all notices that the principal amount, or any portion thereof, and/or
any interest on any instrument or document evidencing all or any part of
Borrower's Obligations is due, notices of any and all proceedings to collect
from the maker, any endorser or any other Guarantor or guarantor of all or any
part of Borrower's Obligations, or from anyone else, and, to the extent
permitted by law, notices of exchange, sale, surrender or other handling of any
security or collateral given to Agent, for its benefit and the ratable benefit
of the Lenders, to secure payment of Borrower's Obligations.

                 No delay on the part of Agent in the exercise of any right or
remedy shall operate as a waiver thereof, and no single or partial exercise by
Agent of any right or remedy shall preclude any further exercise thereof; nor
shall any modification or waiver of any of the provisions of this Master
Corporate Guaranty be binding upon Agent or the Lenders, except as expressly
set forth in a writing duly signed and delivered on Agent's behalf by an
authorized officer or agent of Agent.  Agent's or the Lenders' failure at any
time or times hereafter to require strict performance by the Borrower or any
Guarantor of any of the provisions, warranties, terms and conditions contained
in any promissory note, security agreement, agreement, guaranty, instrument or
document now or at any time or times hereafter executed by the Borrower or any
Guarantor and delivered to Agent and the Lenders shall not waive, affect or
diminish any right of Agent and the Lenders at any time or times hereafter to
demand strict performance thereof and such right shall not be deemed to have
been waived by any act or





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knowledge of Agent or the Lenders, or their respective agents, officers or
employees, unless such waiver is contained in an instrument in writing signed
by an officer or agent of Agent, and directed to the Borrower or a Guarantor,
as applicable, specifying such waiver.  No waiver by Agent and the Lenders of
any default shall operate as a waiver of any other default or the same default
on a future occasion, and no action by Agent or the Lenders permitted hereunder
shall in any way affect or impair Agent's or the Lenders' rights or the
obligations of any Guarantor under this Master Corporate Guaranty.  Any
determination by a court of competent jurisdiction of the amount of any
principal and/or interest owing by the Borrower to Agent and the Lenders shall
be conclusive and binding on each Guarantor irrespective of whether such
Guarantor was a party to the suit or action in which such determination was
made.

                 This Master Corporate Guaranty shall terminate upon payment of
all of the Payment Liabilities (as defined in the Loan Agreement) and the
termination of the Loan Agreement in connection with its terms.

                 This Master Corporate Guaranty shall be binding upon each
Guarantor and upon the successors and permitted assigns of such Guarantor and
shall inure to the benefit of Agent's and the Lenders' respective successors
and assigns; all references herein to the Borrower shall be deemed to include
their successors and permitted assigns and all references herein to Agent or
the Lenders shall be deemed to include their successors and assigns.  The
Borrower's successors and permitted assigns shall include, without limitation,
a receiver, trustee or debtor in possession of or for the Borrower.  All
references to the singular shall be deemed to include the plural where the
context so requires.

                 EACH GUARANTOR HEREBY CONSENTS TO THE JURISDICTION OF STATE OR
FEDERAL COURT LOCATED WITHIN COOK COUNTY, ILLINOIS AND WAIVES ANY OBJECTION
WHICH IT MAY HAVE BASED ON IMPROPER VENUE OR FORUM NON CONVENIENS TO THE
CONDUCT OF ANY PROCEEDING IN ANY SUCH COURT AND CONSENTS THAT ALL SERVICE OF
PROCESS UPON IT BE MADE BY REGISTERED MAIL OR MESSENGER DIRECTED TO IT AT THE
ADDRESS SET FORTH BELOW SUCH GUARANTOR'S SIGNATURE AND THAT SERVICE SO MADE
SHALL BE DEEMED TO BE COMPLETED UPON THE EARLIER OF ACTUAL RECEIPT OR THREE (3)
DAYS AFTER THE SAME SHALL HAVE BEEN POSTED TO SUCH GUARANTOR'S AGENT SET FORTH
BELOW.  EACH GUARANTOR HEREBY IRREVOCABLY APPOINTS CT CORPORATION SYSTEM AS ITS
AGENT FOR THE PURPOSE OF ACCEPTING THE SERVICE OF ANY PROCESS WITHIN THE STATE
OF ILLINOIS.  THE BORROWER, EACH GUARANTOR AND AGENT EACH HEREBY WAIVE, TO THE
EXTENT PERMITTED BY LAW, TRIAL BY JURY.  BORROWER AND EACH GUARANTOR FURTHER
WAIVES ANY BOND OR SURETY OR SECURITY UPON SUCH BOND WHICH MIGHT, BUT FOR THIS
WAIVER, BE REQUIRED OF AGENT.  NOTHING CONTAINED HEREIN SHALL AFFECT THE RIGHT
OF AGENT TO SERVE LEGAL PROCESS IN ANY OTHER MANNER





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PERMITTED BY LAW OR AFFECT THE RIGHT OF AGENT TO BRING ANY ACTION OR PROCEEDING
AGAINST ANY GUARANTOR OR ITS PROPERTY IN THE COURTS OF ANY OTHER JURISDICTION.

                 THIS MASTER CORPORATE GUARANTY SHALL BE GOVERNED IN ALL
RESPECTS BY THE LAWS OF THE STATE OF ILLINOIS.

                 Wherever possible each provision of this Master Corporate
Guaranty shall be interpreted in such manner as to be effective and valid under
applicable law, but if any provision of this Master Corporate Guaranty shall be
prohibited by or invalid under such law, such provision shall be ineffective to
the extent of such prohibition or invalidity without invalidating the remainder
of such provision or the remaining provisions of this Master Corporate
Guaranty.

                 Each Guarantor hereby certifies that it has all necessary
corporate authority to grant and execute this Master Corporate Guaranty.

                 The obligations of each Guarantor are secured by that certain
Master Collateral Security Agreement, of even date herewith, between Agent and
each Guarantor.





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                 IN WITNESS WHEREOF, this Master Corporate Guaranty has been
duly executed by each Guarantor listed below this 17th day of June, 1997.

                                     EACH OF THE SUBSIDIARIES SET FORTH ON 
                                     EXHIBIT A HERETO


                                     By /s/ PHILIP J. ABLOVE
                                        ---------------------------------------

                                     Vice President of each of such Subsidiaries



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                                   EXHIBIT A


PIONEER AMERICAS, INC.
PIONEER CHLOR ALKALI COMPANY, INC.
IMPERIAL WEST CHEMICAL CO.
ALL-PURE CHEMICAL CO.
ALL-PURE CHEMICAL NORTHWEST, INC.
BLACK MOUNTAIN POWER COMPANY