EXHIBIT 4.12

                                 AMENDMENT NO. 4

                                       TO

               REVOLVING CREDIT, TERM LOAN AND SECURITY AGREEMENT

        THIS AMENDMENT NO. 4 ("Amendment") is entered into as of March 25, 2005
by and among PERMA-FIX ENVIRONMENTAL SERVICES, INC., a corporation organized
under the laws of the State of Delaware ("Borrower"), PNC BANK, NATIONAL
ASSOCIATION ("PNC"), the various other financial institutions (together with
PNC, collectively the "Lenders") named in or which hereafter become a party to
the Loan Agreement (as hereafter defined) and PNC as agent for Lenders (in such
capacity, "Agent") and as Issuing Bank.

                                   BACKGROUND

        Borrower, Agent and Lenders are parties to a Revolving Credit, Term Loan
and Security Agreement dated as of December 22, 2000 (as amended, supplemented
or otherwise modified from time to time, the "Loan Agreement") pursuant to which
Lenders provide Borrower with certain financial accommodations.

        Borrower has requested that Lenders amend certain provisions of the Loan
Agreement and Agent, on behalf of Lenders is willing to do so on the terms and
conditions hereafter set forth.

        NOW, THEREFORE, in consideration of any loan or advance or grant of
credit heretofore or hereafter made to or for the account of Borrower by
Lenders, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto hereby agree as
follows:

        1.      Definitions. All capitalized terms not otherwise defined herein
shall have the meanings given to them in the Loan Agreement.

        2.      Amendment to Loan Agreement. Subject to satisfaction of the
conditions precedent set forth in Section 3 below, the Loan Agreement is hereby
amended as follows:

                (a)     Section 1.2 of the Loan Agreement is hereby amended to
provide as follows:

                        (i)     The following defined terms are added in their
appropriate alphabetical order:

                "Amendment No. 4" shall mean Amendment No. 4 to Revolving
                Credit, Term Loan and Security Agreement dated as of March 25,
                2005.

                "Amendment No. 4 Effective Date" shall mean the date when the
                conditions of effectiveness set forth in Section 3 of Amendment
                No. 4 have been met to Agent's satisfaction.

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                "Anti-Terrorism Laws" shall mean any Applicable Laws relating to
                terrorism or money laundering, including Executive Order No.
                13224, the USA Patriot Act, the Applicable Laws comprising or
                implementing the Bank Secrecy Act, and the Applicable Laws
                administered by the United States Treasury Department's Office
                of Foreign Asset Control (as any of the foregoing Applicable
                Laws may from time to time be amended, renewed, extended, or
                replaced).

                "Applicable Law" shall mean all laws, rules and regulations
                applicable to the Person, conduct, transaction, covenant, Other
                Document or contract in question, including all applicable
                common law and equitable principles; all provisions of all
                applicable state, federal and foreign constitutions, statutes,
                rules, regulations and orders of any governmental body, and all
                orders, judgments and decrees of all courts and arbitrators.

                "Executive Order No. 13224" shall mean the Executive Order No.
                13224 on Terrorist Financing, effective September 24, 2001, as
                the same has been, or shall hereafter be, renewed, extended,
                amended or replaced.

                "Preferred Stock" means Borrower's Series 17 Class Q Preferred
                Stock consisting of Borrower's former Series 9 Class I
                Convertible Preferred Stock, Series 14 Class N Convertible
                Preferred Stock, Series 15 Class O Convertible Preferred Stock
                and Series 16 Class P Convertible Preferred Stock.

                "Tennessee Equipment" shall mean the Equipment located at the
                Kingston, TN and Oak Ridge, TN facilities, and more fully set
                forth in the appraisal dated January 28, 2005 conducted by
                Marshall & Stevens Incorporated.

                "Trading with the Enemy Act" shall mean the foreign assets
                control regulations of the United States Treasury Department (31
                CFR, Subtitle B, Chapter V, as amended) and any enabling
                legislation or executive order relating thereto.

                "USA Patriot Act" shall mean the Uniting and Strengthening
                America by Providing Appropriate Tools Required to Intercept and
                Obstruct Terrorism Act of 2001, Public Law 107-56, as the same
                has been, or shall hereafter be, renewed, extended, amended or
                replaced.

                        (ii)    The following defined terms are amended in their
entirety to provide as follows:

                "Amortizing Availability" shall mean $4,000,000, less $48,000 on

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                the fifteenth (15th) day of each month commencing with April 15,
                2005 but reducing to $0 upon the end of the Term. In the event
                any Tennessee Equipment is sold on or after the Amendment No. 4
                Effective Date, the Amortizing Availability shall be further
                reduced by 80% of the appraised OLV value of the applicable
                Tennessee Equipment as set forth in the appraisal referenced in
                the defined term "Tennessee Equipment".

                "Applicable Interest Rate" shall mean an interest rate per annum
                equal to (a) for the Revolving Credit Facility, (i) the sum of
                the Domestic Rate plus one-half of one percent (0.50%) with
                respect to Domestic Rate Loans and (ii) the sum of the
                Eurodollar Rate plus three percent (3.00%) with respect to
                Eurodollar Rate Loans, and (b) for the Term Loan, (i) the sum of
                the Domestic Rate plus one percent (1.00%) with respect to the
                Domestic Rate Loans and (ii) the sum of the Eurodollar Rate plus
                three and one-half percent (3.5%) with respect to Eurodollar
                Rate Loans.

                "L/C Commitment" means the commitment of the Issuing Bank to
                Issue, and the commitment of the Lenders severally to
                participate in, Letters of Credit from time to time Issued or
                outstanding as provided herein, in an aggregate amount not to
                exceed on any date the sum of $1,000,000; provided that the L/C
                Commitment is part of the Revolving Credit Facility, rather than
                a separate independent commitment.

                (b)     Section 2.11(b) of the Loan Agreement is hereby deleted
in its entirety.

                (c)     Section 2.14(c)(i) is hereby amended by inserting "prior
to 10 a.m. (New York time)" immediately prior to "at least five (5) Business
Days".

                (d)     A new Section 2.14(c)(iv) to the Loan Agreement is added
which provides as follows:

                "(iv) Borrower shall authorize and direct any Issuer to name
                Borrower as the "Applicant" or "Account Party" of each Letter of
                Credit. If Agent is not the Issuer of any Letter of Credit,
                Borrower shall authorize and direct the Issuer to deliver to
                Agent all instruments, documents, and other writings and
                property received by the Issuer pursuant to the Letter of Credit
                and to accept and rely upon Agent's instructions and agreements
                with respect to all matters arising in connection with the
                Letter of Credit, or the application therefor."

                (e)     Section 2.14(d)(v) of the Loan Agreement is hereby
amended in its entirety to provide as follows:

                "(v) Each Lender's participation obligation shall continue until
                the

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                last to occur of any of the following events: (x) Agent ceases
                to be obligated to issue or cause to be issued Letters of Credit
                hereunder; (y) no Letter of Credit issued or created hereunder
                remains outstanding and uncancelled and (z) all Persons (other
                than the Borrower) have been fully reimbursed for all payments
                made under or relating to Letters of Credit."

                (f)     Section 2.14(f)(i) of the Loan Agreement is hereby
amended by adding the following to the end thereof:

                "(i) In determining whether to honor any request for drawing
                under any Letter of Credit by the beneficiary thereof, Agent
                shall be responsible only to determine that the documents and
                certificates required to be delivered under such Letter of
                Credit have been delivered and that they comply on their face
                with the requirements of such Letter of Credit and that any
                other drawing condition appearing on the face of such Letter of
                Credit has been satisfied in the manner so set forth."

                (g)     Section 2.14(f)(iii) of the Loan Agreement is amended in
its entirety to provide as follows:

                "(iii) As between Borrower and Issuing Bank, Agent and Lenders,
                Borrower assumes all risks of the acts and omissions of, or
                misuse of the Letters of Credit by, the respective beneficiaries
                of such Letters of Credit; provided, however, that this
                assumption is not intended to, and shall not, preclude
                Borrower's pursuing such rights and remedies as it may have
                against the beneficiary at law or under any other agreement. In
                furtherance and not in limitation of the respective foregoing,
                neither Agent or any of its Affiliates, nor Issuing Bank or any
                of its correspondents, participants or assignees of the Issuing
                Bank shall be responsible for: (i) the form, validity,
                sufficiency, accuracy, genuineness or legal effect of any
                document submitted by any party in connection with the
                application for an issuance of any such Letter of Credit, even
                if it should in fact prove to be in any or all respects invalid,
                insufficient, inaccurate, fraudulent or forged (even if Agent or
                Issuing Bank shall have been notified thereof); (ii) the
                validity or sufficiency of any instrument transferring or
                assigning or purporting to transfer or assign any such Letter of
                Credit or the rights or benefits thereunder or proceeds thereof,
                in whole or in part, which may prove to be invalid or
                ineffective for any reason; (iii) the failure of the beneficiary
                of any such Letter of Credit, or any other party to which such
                Letter of Credit may be transferred, to comply fully with any
                conditions required in order to draw upon such Letter of Credit
                or any other claim of Borrower against any beneficiary of such
                Letter of Credit, or any such transferee, or any dispute

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                between or among Borrower and any beneficiary of any Letter of
                Credit or any such transferee; (iv) errors, omissions,
                interruptions or delays in transmission or delivery of any
                messages, by mail, cable, telegraph, telex or otherwise, whether
                or not they be in cipher; (v) errors in interpretation of
                technical terms; (vi) any loss or delay in the transmission or
                otherwise of any document required in order to make a drawing
                under any such Letter of Credit or of the proceeds thereof;
                (vii) the misapplication by the beneficiary of any such Letter
                of Credit of the proceeds of any drawing under such Letter of
                Credit; or (viii) any consequences arising from causes beyond
                the control of Agent or Issuing Bank, including any governmental
                acts, and none of the above shall affect or impair, or prevent
                the vesting of, any of Agent's or Issuing Bank's rights or
                powers hereunder. Nothing in the preceding sentence shall
                relieve Agent or Issuing Bank from liability for Agent's or
                Issuing Bank's gross negligence or willful misconduct (as
                determined by a court of competent jurisdiction in a final
                non-appealable judgment) in connection with actions or omissions
                described in such clauses (i) through (viii) of such sentence
                but only to the extent of any direct, as opposed to
                consequential or exemplary, damages suffered by Borrower due to
                such actions or omissions or due to Issuing Bank's willful
                failure to pay under any Letter of Credit after presentation to
                it by the beneficiary of a sight draft and certificate(s)
                strictly complying with the terms and conditions of a Letter of
                Credit. In no event shall Agent or Agent's Affiliates or Issuing
                Bank or any of its correspondents, participants or assignees be
                liable to the Borrower for any indirect, consequential,
                incidental, punitive, exemplary or special damages or expenses
                (including without limitation attorneys' fees), or for any
                damages resulting from any change in the value of any property
                relating to a Letter of Credit.

                        Without limiting the generality of the foregoing, Agent
                and each of its Affiliates and Issuing Bank and its
                correspondents, participants or assignees (i) may rely on any
                oral or other communication believed in good faith by it to have
                been authorized or given by or on behalf of the applicant for a
                Letter of Credit, (ii) may honor any presentation if the
                documents presented appear on their face substantially to comply
                with the terms and conditions of the relevant Letter of Credit;
                (iii) may honor a previously dishonored presentation under a
                Letter of Credit, whether such dishonor was pursuant to a court
                order, to settle or compromise any claim of wrongful dishonor,
                or otherwise, and shall be entitled to reimbursement to the same
                extent as if such presentation had initially been honored,
                together with any interest paid by it; (iv) may honor any
                drawing that is payable upon presentation of a statement
                advising negotiation or payment, upon

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                receipt of such statement (even if such statement indicates that
                a draft or other document is being delivered separately), and
                shall not be liable for any failure of any such draft or other
                document to arrive, or to conform in any way with the relevant
                Letter of Credit; (v) may pay any paying or negotiating bank
                claiming that it rightfully honored under the laws or practices
                of the place where such bank is located; and (vi) may settle or
                adjust any claim or demand made on it in any way related to any
                order issued at the applicant's request to an air carrier, a
                letter of guarantee or of indemnity issued to a carrier or any
                similar document (each an "Order") and honor any drawing in
                connection with any Letter of Credit that is the subject of such
                Order, notwithstanding that any drafts or other documents
                presented in connection with such Letter of Credit fail to
                conform in any way with such Letter of Credit.

                        In furtherance and extension and not in limitation of
                the specific provisions set forth above, any action taken or
                omitted by Agent, its Affiliates, Issuing Bank or its
                correspondents, participants or assignees under or in connection
                with the Letters of Credit issued by it or any documents and
                certificates delivered thereunder, if taken or omitted in good
                faith and without gross negligence (as determined by a court of
                competent jurisdiction in a final non-appealable judgment),
                shall not put it under any resulting liability to Borrower or
                any Lender."

                (h)     Section 2.14(g) of the Loan Agreement is hereby amended
in its entirety to provide as follows:

                "Nature of Participation and Reimbursement Obligations. Each
                Lender's obligation in accordance with this Agreement and any
                L/C-Related Document to make the Revolving Advances or
                Participation Advances as a result of a drawing under a Letter
                of Credit, and the obligations of Borrower to reimburse Agent
                and Issuing Bank upon a draw under a Letter of Credit, shall be
                absolute, unconditional and irrevocable, and shall be performed
                strictly in accordance with the terms of this Agreement and each
                such other L/C-Related Document under all circumstances,
                including the following circumstances:

                        (i)     any set-off, counterclaim, recoupment, defense
                or other right which such Lender may have against Agent,
                Borrower or any other Person for any reason whatsoever;

                        (ii)    the failure of Borrower or any other Person to
                comply, in connection with a Letter of Credit Borrowing, with
                the conditions set forth in this Agreement for the making of a
                Revolving Advance, it being acknowledged that such conditions

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                are not required for the making of a L/C Borrowing and the
                obligation of such Lender to satisfy its participation
                obligation under Section 2.14(d);

                        (iii)   any lack of validity or enforceability of any
                Letter of Credit;

                        (iv)    any claim of breach of warranty that might be
                made by Borrower or any Lender against the beneficiary of a
                Letter of Credit, or the existence of any claim, set-off,
                recoupment, counterclaim, crossclaim, defense or other right
                which Borrower or any Lender may have at any time against a
                beneficiary, any successor beneficiary or any transferee of any
                Letter of Credit or the proceeds thereof (or any Persons for
                whom any such transferee may be acting), Agent or any Lender or
                any other Person, whether in connection with this Agreement, the
                transactions contemplated herein or any unrelated transaction
                (including any underlying transaction between Borrower or any
                Subsidiaries of Borrower and the beneficiary for which any
                Letter of Credit was procured);

                        (v)     the lack of power or authority of any signer of
                (or any defect in or forgery of any signature or endorsement on)
                or the form of or lack of validity, sufficiency, accuracy,
                enforceability or genuineness of any draft, demand, instrument,
                certificate or other document presented under or in connection
                with any Letter of Credit, or any fraud or alleged fraud in
                connection with any Letter of Credit, or the transport of any
                property or provisions of services relating to a Letter of
                Credit, in each case even if Agent or any of Agent's Affiliates
                or Issuing Bank or any of its correspondents, participants or
                assignees has been notified thereof;

                        (vi)    payment by Agent or Issuing Bank under any
                Letter of Credit against presentation of a demand, draft or
                certificate or other document which does not comply with the
                terms of such Letter of Credit;

                        (vii)   the solvency of, or any acts or omissions by,
                any beneficiary of any Letter of Credit, or any other Person
                having a role in any transaction or obligation relating to a
                Letter of Credit, or the existence, nature, quality, quantity,
                condition, value or other characteristic of any property or
                services relating to a Letter of Credit;

                        (viii)  any failure by the Agent or any of Agent's
                Affiliates or Issuing Bank or any of its correspondents,
                participants or assignees to issue any Letter of Credit in the
                form requested by Borrower, unless such Person has received
                written notice from

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                Borrower of such failure within three (3) Business Days after
                the Agent or Issuing Bank shall have furnished Borrower a copy
                of such Letter of Credit and such error is material and no
                drawing has been made thereon prior to receipt of such notice;

                        (ix)    any Material Adverse Effect on Borrower or any
                Guarantor;

                        (x)     any breach of this Agreement or any Loan
                Document by any party thereto;

                        (xi)    the occurrence or continuance of an insolvency
                proceeding with respect to Borrower or any Guarantor;

                        (xii)   the fact that a Default or Event of Default
                shall have occurred and be continuing;

                        (xiii)  the fact that the Term shall have expired or
                this Agreement or the Obligations hereunder shall have been
                terminated; and

                        (xiv)   any other circumstance or happening whatsoever,
                whether or not similar to any of the foregoing, including any
                other circumstance that might otherwise constitute a defense
                available to, or a discharge of, Borrower or a Guarantor.

                Borrower and each Lender agrees to be bound by the terms of any
                L/C-Related Document and by Agent's or Issuing Bank's
                interpretations of any Letter of Credit issued for Borrower's
                account and by Agent's or Issuing Bank's written regulations and
                customary practices relating to letters of credit, though
                Agent's interpretations may be different from Borrower's or such
                Lender's own. In the event of a conflict between the Letter of
                Credit Application and this Agreement, this Agreement shall
                govern. It is understood and agreed that, except in the case of
                gross negligence or willful misconduct (as determined by a court
                of competent jurisdiction in a final non-appealable judgment),
                Agent or Issuing Bank shall not be liable for any error,
                negligence and/or mistakes, whether of omission or commission,
                in following Borrower's instructions or those contained in the
                Letters of Credit or any modifications, amendments or
                supplements thereto."

                (i)     Section 2.14(i)(i) of the Loan Agreement is hereby
amended by replacing the phrase "rate per annum equal to three percent (3%) per
annum" with "rate per annum equal to two and one-half percent (2 1/2%) per
annum."

                (j)     A new Section 2.14(l) to the Loan Agreement is hereby
added which provides as follows:

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                "(l) Indemnity. In addition to amounts payable as provided in
                Section 15.5, the Borrower hereby agrees to protect, indemnify,
                pay and save harmless Agent, any of Agent's Affiliates and
                Issuing Bank and any of its correspondents, participants or
                assignees that have issued a Letter of Credit from and against
                any and all claims, demands, liabilities, damages, taxes,
                penalties, interest, judgments, losses, costs, charges and
                expenses (including reasonable fees, expenses and disbursements
                of counsel and allocated costs of internal counsel) which such
                Person may incur or be subject to as a consequence, direct or
                indirect, of the issuance of any Letter of Credit, other than as
                a result of (a) the gross negligence or willful misconduct of
                such Person as determined by a final and non-appealable judgment
                of a court of competent jurisdiction or (b) the wrongful
                dishonor by such Person of a proper demand for payment made
                under any Letter of Credit, except if such dishonor resulted
                from any act or omission, whether rightful or wrongful, of any
                present or future de jure or de facto Governmental Body."

                (k)     Section 3.2 of the Loan Agreement is hereby amended in
its entirety to provide as follows:

                3.2     Facility and Other Fees. If, for any month during the
                Term, the average daily unpaid balance of the Revolving Credit
                Facility Advances and the undrawn amount of any outstanding
                Letters of Credit for each day of such month does not equal the
                Revolving Credit Limit, then Borrower shall pay to Agent for the
                ratable benefit of Lenders a fee at a rate equal to three-eights
                of one percent (.375%) per annum on the amount by which the
                Revolving Credit Limit exceeds such average daily unpaid
                balance. Such fee shall be payable to Agent in arrears on the
                last day of each quarter and shall be calculated as provided in
                Section 3.3. In addition, Borrower shall pay the fees set forth
                in the Fee letter.

                (l)     A new Section 5.26 is hereby added to the Loan Agreement
to provide as follows:

                5.26    Anti-Terrorism Laws.

                (a)     General. Neither Borrower nor any Affiliate of Borrower
                is in violation of any Anti-Terrorism Law or engages in on
                conspires to engage in any transaction that evades or avoids, or
                has the purpose of evading or avoiding, or attempts to violate,
                any of the prohibitions set forth in any Anti-Terrorism Law.

                (b)     Executive Order No. 13224. Neither Borrower nor any
                Affiliate of Borrower or their respective agents acting or
                benefiting
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                in any capacity in connection with the Advances or other
                transactions hereunder, is any of the following (each a "Blocked
                Person"):

                        (i)     a person that is listed in the annex to, or is
                otherwise subject to the provisions of, the Executive order No.
                13224;

                        (ii)    a person owned or controlled by, or acting for
                or on behalf of, any persona that is listed in the annex to, or
                is otherwise subject to the provisions of the Executive Order
                No. 13224;

                        (iii)   a Person or entity with which any lender is
                prohibited from dealing or otherwise engaged in any transaction
                by any Anti-Terrorism Law;

                        (iv)    a Person or entity that comments, threatens or
                conspires to commit or supports "terrorism" as defined in the
                Executive Order No. 13324;

                        (v)     a person or entity that is named as a "specially
                designated national" on the most current list published by the
                U.S. Treasury Department Office of Foreign Asset Control at its
                official website or any replacement website or other replacement
                official publication of such list; or

                        (iv)    a person or entity who is affiliated or
                associated with a Person or entity listed above.

                Nether Borrower or to the knowledge of Borrower, any of its
                agents acting in any capacity in connection with the Advances or
                other transactions hereunder (i) conducts any business or
                engages in making or receiving any contribution of funds, goods
                or services to or for the benefit of any Blocked Person, or (ii)
                deal in, or otherwise engages in any transaction relating to,
                any property or interests in property blocked pursuant to
                Executive Order No. 13324.

                (m)     Section 6.5 of the Loan Agreement is amended in its
entirety to provide as follows:

                6.5.    Tangible Adjusted Net Worth. Maintain Tangible Adjusted
                Net Worth in an amount not less then $30,000,000 at all times.

                (n)     Section 7.6 of the Loan Agreement is hereby amended in
its entirety to provide as follows:

                7.6     Capital Expenditures. Contract for, purchase or make any
                expenditure or commitments for fixed or capital assets
                (including
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                Capitalized leases) in any fiscal year commencing with the
                fiscal year ending 2005 in an aggregate amount for all Credit
                Parties in excess of (a) in the case of Unfinanced Capital
                Expenditures, $4,000,000 plus the amount of any cash net
                proceeds of any equity issuance received by any Credit Party in
                any such fiscal year, and (b) in the case of all Capital
                Expenditures (whether financed or unfinanced), $6,000,000.

                (o)     Section 7.11 of the Loan Agreement is hereby amended by
replacing the amount "$250,000" with "$500,000."

                (p)     The following sections are hereby added to the end of
Article VII to provide as follows:

                7.20.   Anti-Terrorism Laws. Borrower shall not, until
                satisfaction in full of the Obligations and termination of this
                Agreement, nor shall it permit an Affiliate or agent to:

                        (a)     Conduct any business or engage in any
                transaction or deal with any Blocked Person, including making or
                receiving any contribution of funds, goods or services to or for
                the benefit of any Blocked Person.

                        (b)     Deal in, or otherwise engage in any transaction
                relating to, any property or interests in property blocked
                pursuant to the Executive Order No. 13324.

                        (c)     Engage in or conspire to engage in any
                transaction that evades or avoids, or has the purpose of evading
                or avoiding, or attempts to violate, any of the publications set
                forth in the Executive Order No. 13324, the USA Patriot Act or
                any other Anti-Terrorism Law. Borrower shall deliver to Agent
                any certification or other evidence requested from time to time
                by Agent in its sole discretion, confirming Borrower's
                compliance with this Section.

                7.21    Trading with the Enemy Act. Engage in any business or
                activity in violation of the Trading with the Enemy Act.

                (q)     Section 13.1 of the Loan Agreement is hereby amended in
its entirety to provide as follows:

                13.1.   Term. This Agreement, which shall insure to benefit of
                and shall be binding upon the respective successors and
                permitted assigns of Borrower, Agent and each Lender, shall
                become effective on the date hereof and shall continue in full
                force and effect until May 31, 2008 (the "Termination Date")
                unless sooner terminated as herein provided. Borrower may
                terminate this

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                Agreement at any time upon sixty (60) days' prior written notice
                upon payment in full of the Obligations. In the event that the
                Obligations are prepaid in full prior to the Termination Date
                (the date of such prepayment hereinafter referred to as the
                "Early Termination Date"), Borrower shall pay to Agent for the
                benefit of Lenders an early termination fee in an amount equal
                to (x) one percent (1.00%) of the Total Financing Amount if the
                Early Termination Date occurs on or after the Amendment No. 4
                Effective Date, to and including the date immediately preceding
                the first anniversary of the Amendment No. 4 Effective Date, and
                (y) one-half of one percent (0.50%) of the Total Financing
                Amount if the Early Termination Date occurs on or after the
                first anniversary of the Amendment No. 4 Effective Date but
                prior to the second anniversary of the Amendment No. 4 Effective
                Date. In the event the Early Termination Date occurs on or after
                the second anniversary of the Amendment No. 4 Effective Date, no
                early termination fee shall be due from Borrower.

        3.      Conditions of Effectiveness. This Amendment shall become
effective upon satisfaction of the following conditions precedent: Agent shall
have received (i) four (4) copies of this Amendment executed by Borrower and
consented and agreed to by Guarantors, (ii) an amendment fee of $140,000 (which
fee shall be charged to Borrower's Account), (iii) a copy of the resolutions, in
form and substance reasonably satisfactory to Agent, of the Board of Directors
of Borrower authorizing the execution, delivery and performance of this
Amendment and (iv) such other certificates, instruments, documents, agreements
and opinions of counsel as may be required by Agent or its counsel, each of
which shall be in form and substance satisfactory to Agent and its counsel.

        4.      Representations and Warranties. Borrower hereby represents and
warrants as follows:

                (a)     This Amendment and the Loan Agreement, as amended
hereby, constitute legal, valid and binding obligations of Borrower and are
enforceable against Borrower in accordance with their respective terms.

                (b)     Upon the effectiveness of this Amendment, Borrower
hereby reaffirms all covenants, representations and warranties made in the Loan
Agreement to the extent the same are not amended hereby and agrees that all such
covenants, representations and warranties shall be deemed to have been remade as
of the effective date of this Amendment.

                (c)     No Event of Default or Default has occurred and is
continuing or would exist after giving effect to this Amendment.

                (d)     Borrower has no defense, counterclaim or offset with
respect to the Loan Agreement.

                (e)     Borrower is incorporated in the State of Delaware and
the Guarantors are

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incorporated in the states set forth on Schedule 5.2(a) hereto.

        5.      Effect on the Loan Agreement.

                (a)     Upon the effectiveness of Section 2 hereof, each
reference in the Loan Agreement to "this Agreement," "hereunder," "hereof,"
"herein" or words of like import shall mean and be a reference to the Loan
Agreement as amended hereby.

                (b)     Except as specifically amended herein, the Loan
Agreement, and all other documents, instruments and agreements executed and/or
delivered in connection therewith, shall remain in full force and effect, and
are hereby ratified and confirmed.

                (c)     The execution, delivery and effectiveness of this
Amendment shall not operate as a waiver of any right, power or remedy of Agent
or any Lender, nor constitute a waiver of any provision of the Loan Agreement,
or any other documents, instruments or agreements executed and/or delivered
under or in connection therewith.

        6.      Governing Law. This Amendment shall be binding upon and inure to
the benefit of the parties hereto and their respective successors and assigns
and shall be governed by and construed in accordance with the laws of the State
of New York.

        7.      Headings. Section headings in this Amendment are included herein
for convenience of reference only and shall not constitute a part of this
Amendment for any other purpose.

        8.      Counterparts. This Amendment may be executed by the parties
hereto in one or more counterparts, each of which shall be deemed an original
and all of which when taken together shall constitute one and the same
agreement.

        IN WITNESS WHEREOF, this Amendment has been duly executed as of the day
and year first written above.

                                          PERMA-FIX ENVIRONMENTAL SERVICES, INC.

                                          By:    /s/ Richard T. Kelecy
                                                 -------------------------------
                                          Name:  Richard T. Kelecy
                                          Title: V.P. and CFO

                                          PNC BANK, NATIONAL ASSOCIATION, as
                                          Agent and Lender

                                          By:    /s/ Alex M. Council, IV
                                                 -------------------------------
                                          Name:  Alex M. Council, IV
                                          Title: Vice President

                [SIGNATURES CONTINUED ON FOLLOWING PAGE]

<PAGE>

CONSENTED AND AGREED TO:

SCHREIBER, YONLEY AND ASSOCIATES, INC.
PERMA-FIX TREATMENT SERVICES, INC.
PERMA-FIX OF FLORIDA, INC.
PERMA-FIX OF MEMPHIS, INC.
PERMA-FIX OF DAYTON, INC.
PERMA-FIX OF FT. LAUDERDALE, INC.
PERMA-FIX OF ORLANDO, INC.
PERMA-FIX OF SOUTH GEORGIA, INC.
PERMA-FIX OF MICHIGAN, INC.
DIVERSIFIED SCIENTIFIC SERVICES, INC.
INDUSTRIAL WASTE MANAGEMENT, INC.
EAST TENNESSEE MATERIALS & ENERGY
CORPORATION
PERMA-FIX OF MARYLAND, INC.
PERMA-FIX OF PITTSBURGH, INC.

By:    /s/ Richard T. Kelecy
       --------------------------
Name:  Richard T. Kelecy
Title: Vice President
of each of the foregoing entities