Contact: Millennium Chemicals Inc.              Lyondell
         Mickey Foster                          Jackie Wilson (media)
         Vice President - Investor Relations    (713) 652-4596
         (732) 603-6777                         Kevin DeNicola (investors)
                                                (713) 652-4590

                              FOR IMMEDIATE RELEASE


             LYONDELL AND MILLENNIUM COMPLETE EQUISTAR JOINT VENTURE

Houston,  Texas,  Iselin,  New Jersey and  London,  England,  December 1, 1997 -
Lyondell  Petrochemical  Company (NYSE:LYO) and Millennium Chemicals Inc. (NYSE:
MCH)  announced  today  that the  joint  venture  transaction  to form  Equistar
Chemicals LP,  combining both companies'  olefins and polymers  businesses,  has
been completed. Equistar is now the largest and one of the lowest-cost producers
of ethylene and polyethylene in North America. Equistar is owned 57% by Lyondell
and 43% by Millennium.

With the completion of the transaction,  Millennium  Chemicals has received $750
million today in cash and, in addition,  expects to receive  approximately  $250
million more over the next couple of months.

William  M.  Landuyt,   Chairman  and  Chief  Executive  Officer  of  Millennium
Chemicals,  said,  "We are pleased  that  Equistar  has been  launched  right on
schedule.  We anticipate  that this unique  combination  of assets and attitudes
will result in the creation of added economic value for Millennium shareholders.
The added  financial  flexibility  that results from the transaction has already
been put to use as we are on track to  acquire  the Thann et  Mulhouse  titanium
dioxide and specialty and intermediate  chemicals business from Rhone Poulenc by
year end."

Dan F. Smith,  President and Chief Executive  Officer of Lyondell,  said,  "This
transaction  represents a major step in improving  Lyondell's  earnings and cash
flow outlook during all parts of the business cycle.  With Equistar,  as well as
with our majority interest in LYONDELL-CITGO  Refining Company Ltd., Lyondell is
well positioned to generate  significant  cash flow over the next several years,
which will  provide a broad  spectrum of value  creation  opportunities  for the
company." Smith is also serving as Chief Executive Officer of Equistar.

Lyondell  Petrochemical Company (website:  www.lyondell.com) is a major chemical
and refining company,  with majority ownership positions in the premier olefins,
polymers and refining companies in North America.

Lyondell Petrochemical Company is

     The largest  producer of ethylene,  propylene  and  polyethylene  in North
     America and a leading  producer  of high  value-added  specialty  polymers,
     color  concentrates  and  polymeric  powder  through  its 57%  interest  in
     Equistar Chemicals, LP.

     One of the largest  and most  profitable  refiners  in the United  States,
     processing very heavy Venezuelan crude oil to produce gasoline,  low sulfur
     diesel and jet fuel,  through its 58% interest in  LYONDELL-CITGO  Refining
     Company Ltd.

     The third largest methanol producer in the U.S.,  through its 75% interest
     in Lyondell Methanol Company LP.

Millennium   Chemicals  Inc.  (website:   www.millenniumchem.com)   is  a  major
international  chemicals company, with leading market positions in a broad range
of commodity, industrial, performance and specialty chemicals.

Millennium Chemicals Inc. is

     the  second-largest  producer  of TiO2 in the United  States and  third-
     largest  in the world and a leading  producer of titanium tetrachloride;
     the second-largest producer of acetic acid and vinyl acetate monomer in 
     the United States;
     
     a leading  producer of fragrance and flavor  chemicals and other products,
     including  cadmium/selenium  pigments  and silica gel; and through its 43%
     interest  in  Equistar   Chemicals  LP,  a  joint  venture  with  Lyondell
     Petrochemicals, a partner in the largest producer of ethylene,  propylene 
     and  polyethylene  in North America and a leading producer of high value-
     added specialty polymers, color concentrates and polymeric powders.

The statements in this release relating to matters that are not historical facts
are forward-looking statements that involve risks and uncertainties,  including,
but not limited to,  future global  economic  conditions,  production  capacity,
competitive  products and prices and other risks and  uncertainties  detailed in
the Securities and Exchange  Commission  filings of Lyondell  Petrochemicals and
Millennium Chemicals.