Exhibit 99.10

                     DTC PARTICIPANT OVER-SUBSCRIPTION FORM

                                       FOR
                               RIGHTS OFFERING BY
                            HUDSON TECHNOLOGIES, INC.
                           OF NON-TRANSFERABLE RIGHTS
                             EXERCISABLE TO PURCHASE
                                  COMMON SHARES


THIS FORM IS TO BE USED ONLY BY DEPOSITORY TRUST COMPANY PARTICIPANTS TO
EXERCISE THE OVER-SUBSCRIPTION PRIVILEGE IN RESPECT OF RIGHTS WITH RESPECT TO
WHICH THE BASIC SUBSCRIPTION RIGHT WAS EXERCISED AND DELIVERED THROUGH THE
FACILITIES OF THE DEPOSITORY TRUST COMPANY. ALL OTHER EXERCISES OF
OVER-SUBSCRIPTION PRIVILEGES MUST BE EFFECTED BY THE DELIVERY OF THE STOCKHOLDER
SUBSCRIPTION AGREEMENT.

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THE TERMS AND CONDITIONS OF THE RIGHTS OFFERING ARE SET FORTH IN THE PROSPECTUS
OF HUDSON TECHNOLOGIES, INC. ("HUDSON") DATED AUGUST __, 2003 (THE "PROSPECTUS")
AND ARE INCORPORATED HEREIN BY REFERENCE. COPIES OF THE PROSPECTUS ARE AVAILABLE
UPON REQUEST FROM HUDSON AND THE SUBSCRIPTION AGENT.

                      ------------------------------------

VOID UNLESS RECEIVED BY THE SUBSCRIPTION AGENT WITH PAYMENT IN FULL BY 5:00
P.M., EASTERN TIME, ON SEPTEMBER __, 2003 OR SUCH LATER DATE AS MAY BE EXTENDED
BY HUDSON (THE "EXPIRATION DATE").

                      ------------------------------------

1.    The undersigned hereby certifies to HUDSON and the Subscription Agent that
      it is a participant in The Depository Trust Company ("DTC") and that it
      has exercised the Basic Subscription Right in respect of rights (the
      "Rights") to purchase shares of common stock (the "Common Stock") of
      HUDSON and delivered such exercised Rights to the Subscription Agent by
      means of transfer to the DTC account of the Subscription Agent. The
      undersigned hereby certifies to HUDSON and the Subscription Agent that it
      owned ____________ Shares of Common Stock on August 1, 2003 (the "Record
      Date").

2.    The undersigned hereby exercises the Over-subscription Privilege to
      purchase, to the extent available, ____________ shares of Common Stock of
      HUDSON and certifies to HUDSON and the Subscription Agent that such
      Over-subscription Privilege is being exercised for the account or accounts
      of persons (which may include the undersigned) on whose behalf all Basic
      Subscription Rights have been exercised.

3.    The undersigned understands that payment of the Subscription Price of
      $____ per share for each share of Common Stock subscribed for pursuant to
      the Over-subscription Privilege must be



      received by the Subscription Agent at or before 5:00 p.m. Eastern time on
      the Expiration Date and represents that such payment, in the aggregate
      amount of $____________ either (check appropriate box):

            |_|   is being delivered to the Subscription Agent herewith;

                                       or

            |_|   has been delivered separately to the Subscription Agent;

and, is or was delivered in the manner set forth below (check appropriate box
and complete information relating thereto):

            |_|   uncertified check

            |_|   certified check

            |_|   bank draft

            |_|   wire transfer

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Basic Subscription Confirmation Number

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DTC Participant

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Name of DTC Participant


By:
   --------------------------------------------
         Name:
         Title:

Contact Name:
             -------------------------------

Phone Number:
             -------------------------------

Dated:                              , 2003
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