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                                                                    Exhibit 99.1


Press release,  dated September 19, 2000, announcing the completion of the sale
of the LNG business.

FOR IMMEDIATE RELEASE

                                          Contact: Eduardo E. Cordeiro
                                                 Director,  Investor Relations
                                                 (617) 342-6244
                                                 Ethel Shepard
                                                 Manager, Corporate Affairs
                                                 (617) 342-6254

                       Cabot Corporation Completes Sale of
                         its LNG Unit to Tractebel, Inc.

BOSTON, MA (September 19, 2000) - Cabot Corporation  (NYSE: CBT) today announced
the  completion  of its sale of Cabot  LNG,  LLC to  Tractebel,  Inc.,  the U.S.
subsidiary of Tractebel Group,  for $680 million in cash.  Tractebel is a global
energy and services  business and is the sole arm for the energy  activities  of
Suez Lyonnaise des Eaux.

"We are very pleased with the successful  completion of this  transaction," said
Samuel W. Bodman,  Chairman and CEO, Cabot Corporation.  "Cabot is proud to have
grown the LNG business  into a successful  and widely  recognized  leader in the
energy industry.  The Company and its shareholders  have benefited  greatly from
our  investment in LNG. We will continue to focus our attention and resources on
growing our core businesses and on developing new  opportunities to create value
for Cabot's shareholders."

Cabot LNG imports liquefied  natural gas (LNG) from Algeria,  Trinidad and other
countries to its marine terminal in Everett, MA where it is distributed as vapor
and liquid to utilities,  electric power generators, and industrial end users in
the Northeast United States.

About Cabot Corporation

Cabot  Corporation  is a  global  specialty  chemicals  and  materials  company.
Headquartered  in Boston,  MA,  Cabot's major  products are carbon black,  fumed
silica, inkjet colorants, and capacitor materials. Cabot has approximately 4,800
employees  in more  than 45  manufacturing  plants  and  offices  located  in 23
countries around the world.

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