Exhibit No. 99.1

Official Press Release of the MarketSpan Board:


                        MARKETSPAN ANNOUNCES CEO CHANGE
                WILLIAM CATACOSINOS RESIGNS; ROBERT CATELL NAMED

     July 31, 1998 (Brooklyn,  NY) u MARKETSPAN  CORPORATION (NYSE:MN) announced
today  that Dr.  William J.  Catacosinos  has  resigned  as  Chairman  and Chief
Executive  Officer and that Robert B. Catell,  the  company's  President,  would
become Chairman and CEO. These changes were effective immediately.

      In accepting Dr.  Catacosinos'  resignation,  the Board  acknowledged  his
contributions  to  LILCO,  MarketSpan's  predecessor  company,  over the past 14
years.  The Board also  expressed  confidence in Bob Catell's  leadership and in
MarketSpan's   ability  to  build   confidence   among  all  of  the   company's
stakeholders.

      Robert  Catell  said,  "Our focus and intent is to move ahead  strongly in
serving  our  customers.  We have the  people,  the  resources,  and the will to
maximize shareholder value, deliver superior services to customers,  and provide
opportunities for employees."

      Dr.  Catacosinos  said,  "I  leave  with  a  sense  of  accomplishment  in
transforming  LILCO  from a deeply  troubled  utility  into a  customer  focused
company with a clean balance  sheet.  For these  accomplishments,  I am proud to
have been associated with the LILCO management team and its dedicated workforce.
I am confident that the new MarketSpan  leadership will  successfully  serve all
parties."

      Before joining  MarketSpan,  Mr. Catell,  61, was Chairman,  President and
Chief  Executive  Officer of KeySpan Energy  Corporation,  formed in 1997 as the
parent  company of Brooklyn Union Gas Co., which combined with segments of LILCO
to form MarketSpan. Mr. Catell joined Brooklyn Union Gas in 1958 after receiving
both his bachelor's  and master's  degrees in mechanical  engineering  from City
College  of New York.  He became an officer  of  Brooklyn  Union Gas in 1974 and
served as President and Chief Executive from 1991.