

FOR IMMEDIATE RELEASE
December 31, 1997

Contact:     Guy T. Marcus          Dirk Vande Beek           Li-San Hwang
             V. P.-Inv. Rel.        News Media                President & CEO
             Halliburton            Halliburton               Tetra Tech
             (214) 978-2691         (713) 676-8097            (626) 351-4664


              TETRA TECH, INC. COMPLETES PURCHASE OF HALLIBURTON'S
                        ENVIRONMENTAL SERVICES BUSINESS


         DALLAS,  Texas - Halliburton  Company  (NYSE:HAL) and Tetra Tech,  Inc.
(NASDAQ:WATR)  jointly announced today that Halliburton's Brown & Root, Inc. and
Halliburton  NUS  Corporation   completed  the  sale  of  the  assets  of  their
environmental services business to Tetra Tech. The cash transaction is valued at
about $32 million,  but is subject to certain  December 31, 1997 closing balance
sheet adjustments.
         The environmental  business acquired by Tetra Tech provides consulting,
engineering   and  design   services  for  the   environmental   remediation  of
contaminated  air,  water  and soil  conditions.  Customers  include  industrial
clients as well as federal,  state and local governments,  focused in the United
States.
         Tetra Tech provides comprehensive  environmental and telecommunications
support  services  including research  and development,  engineering and design,

                                     -more-

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Halliburton Company                    2

construction  management,  and  operation and  maintenance.  Tetra Tech provides
these services to a broad base of customers world-wide.
     Halliburton  Company  is one  of the  world's  largest  diversified  energy
services, engineering, maintenance, and construction companies. Founded in 1919,
Halliburton  provides a broad range of energy services and products,  industrial
and marine engineering and construction services.

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