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                                    EXHIBIT A


                 RELEVANT SUBSIDIARIES OF PARENT HOLDING COMPANY

PART A: TCW ENTITIES

PARENT HOLDING COMPANY:

            The TCW Group, Inc.

            Robert Day (an individual who may be deemed to control The TCW
            Group, Inc.)


RELEVANT SUBSIDIARIES THAT ARE PERSONS DESCRIBED IN RULE 13d-1(b):

     (i)    Trust Company of the West, a California corporation and a bank as
     defined in Section 3(a)(6) of the Securities Exchange Act of 1934.

     (ii)   TCW Asset Management Company, a California corporation and an
     Investment Adviser registered under Section 203 of the Investment Advisers
     Act of 1940.


Note:       No Common Stock of ABS Industries, Inc. is held directly by The TCW
            Group, Inc.  Other than the indirect holdings of The TCW Group, Inc.
            no Common Stock of ABS Industries, Inc. is held directly or
            indirectly by Robert Day, an individual who may be deemed to control
            The TCW Group, Inc.

PART B: NON TCW ENTITIES

PARENT HOLDING COMPANY:

            Robert Day (an individual who may be deemed to control the holders
            described below which are not subsidiaries of The TCW Group, Inc.)

RELEVANT SUBSIDIARIES THAT ARE PERSONS DESCRIBED IN
RULE 13d-1(b):

            Oakmont Corporation, a California corporation and an Investment
            Adviser registered under Section 203 of the Investment Advisers Act
            of 1940.

            Cypress International Partners Limited, a British Virgin Islands
            corporation and an Investment Adviser registered under Section 203
            of the Investment Advisers Act of 1940.


                                       A-1

