Exhibit 10.21

                                 AMENDMENT TO
                             EMPLOYMENT AGREEMENT

      THIS AMENDMENT TO EMPLOYMENT AGREEMENT ("Amendment"), effective as
of the 30th day of October,  1998,  is entered  into by and between The Brooklyn
Union  Gas  Company,  a New York  Corporation,  KeySpan  Energy  Corporation,  a
Delaware  corporation,  MarketSpan  Corporation,  a New York  Corporation  doing
business as KeySpan  Energy,  hereinafter  referred to either by company name or
collectively as the "Company" and David L. Phillips,  hereinafter referred to as
"Employee."

      WHEREAS,  Employee  and The Brooklyn  Union Gas Company  entered into that
certain  EMPLOYMENT  AGREEMENT  (the  "Agreement")  effective  January  1, 1997,
expressly  providing  for the term  employment of Employee by the Company in the
capacity of Senior Vice President, Strategic Planning & Corporate Development.

      WHEREAS,  Article III(d) of the Agreement provides that Employee shall not
be eligible to  participate  in The Brooklyn  Union Senior  Executive  Change of
Control  Severance  Plan (the "BU  Plan"),  and  Article  V(a) of the  Agreement
provides that, notwithstanding anything contained in the BU Plan, Employee shall
be entitled to specific benefits set forth in the Agreement; and

      WHEREAS,  on October 30, 1998,  the Board of  Directors of KeySpan  Energy
adopted a KeySpan  Energy  Senior  Executive  Change of Control  Severance  Plan
("KeySpan Plan").

      NOW THEREFORE,  as additional  incentive to Employee in consideration  for
rendering  services  to  the  Company  and  in  order  to  provide  similar  and
appropriate  separation  benefits to Employee as are currently provided to other
senior  executives of the Company in similar  positions,  and for other good and
valuable  consideration  the  receipt  and  sufficiency  of  which  are  hereby,
acknowledged by the Company, the undersigned hereby agrees as follows:

      1. (a) Article  III(d) of the  Agreement and Article V(a) of the Agreement
are hereby  amended to provide that Employee shall be entitled to the separation
benefits and all other benefits set forth in the KeySpan Plan.

            (b)  Employee  and the Company  acknowledge  and agree that,  in the
event of a change of  control  (as such term is defined  in the  KeySpan  Plan),
Employee  shall be entitled to all  separation  benefits in accordance  with the
KeySpan Plan and that such  benefits  shall be in lieu of and not in addition to
the benefits set forth in Article V of the Agreement  and that,  notwithstanding
anything to the  contrary in the  Agreement,  the change of control  provisions,
provisions  relating to Gross-Up  Payments (as defined in the KeySpan  Plan) and
all other  provisions of the KeySpan Plan shall apply when  inconsistent  or not
addressed in the Agreement.

            (c) In accordance  with Section 3.1 of the KeySpan Plan, the Company
hereby agrees that  Schedule I of the KeySpan Plan shall  designate the Employee
as a  Participant  (as defined in the KeySpan Plan) and, for the purposes of the
KeySpan Plan,  the Multiple (as defined in the KeySpan Plan) for Employee  shall
be equal to the Multiple set forth on Schedule I of the Key Span


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Plan for all senior executive officers of the Company.

      2. This amendment is effective as of the date above indicated.

      IN WITNESS WHEREOF, the execution hereof shall be effective as of the date
hereinabove indicated.

THE BROOKLYN UNION GAS COMPANY                  EMPLOYEE

By:  /s/ Robert B. Catell                      By:   /s/ David L. PhillipsN
--------------------------                     --------------------------
Name: Robert B. Catell                          Name: David L. Phillips
Title:Chairman & CEO


KEYSPAN ENERGY CORPORATION


By:   /s/ Robert C. Catell
--------------------------
Name: Robert B. Catell
Title:Chairman & CEO


KEYSPAN ENERGY CORPORATION


By:  /s/ Robert B. Catell   
----------------------------
Name: Robert B. Catell
Title:Chairman & CEO






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