Exhibit 99.1

                                                                       NEWS
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KeySpan Corporation                                        For Immediate Release

Contacts:         Investors                                Media Relations
                  George Laskaris                          Andrea Staub
                  718.403.2526                             516.545.5052
                                                           516.824.1241 (pager)


      KeySpan Reduces its Ownership in Houston Exploration from 55% to 24%
            through an Exchange for a Houston Exploration Subsidiary

KeySpan Corporation  (NYSE:KSE)  announced today that the company plans to enter
into an agreement with The Houston  Exploration  Company  (NYSE:THX) under which
KeySpan will  transfer to Houston  Exploration  10.8  million  shares of Houston
Exploration  common  stock  in  exchange  for  100% of a  wholly  owned  Houston
Exploration  subsidiary,  Seneca-Upshur  Petroleum,  Inc.  At  the  time  of the
exchange,  the  subsidiary  will hold all of Houston  Exploration's  Appalachian
Basin assets and an amount of additional  cash  calculated so as to equalize the
value  of the  operating  business  and the  Houston  Exploration  shares  being
exchanged.

The transaction is consistent  with the business  strategies of both KeySpan and
Houston Exploration. As previously discussed,  KeySpan does not consider Houston
Exploration to be a strategic  holding and has been working to  restructure  its
stake in the company in a manner  that will be  beneficial  to both  KeySpan and
Houston Exploration.

"This transaction  represents an important step to restructuring our interest in
Houston Exploration. We welcome Seneca-Upshur into the KeySpan family and intend
to grow this business  through  additional  investments in energy related assets
that support our core businesses," said Robert B. Catell, KeySpan's Chairman and
Chief  Executive  Officer.  "This  transaction  allows  the  Company  to further
concentrate on executing its strategy of growing its core energy businesses."

The  parties  have  ascribed a value of $60 million  dollars to the  Appalachian
Basin  producing  assets.  At December 31,  2003,  these  properties  had proved
reserves  of 50.5  billion  cubic  feet of natural  gas  equivalent  (Bcfe),  or
approximately  7 percent of Houston  Exploration's  total proved  reserves.  The
Appalachian  assets  include  properties  originally  acquired  and  owned  by a
predecessor  company to KeySpan in the early 1970's to strengthen its gas supply
strategy. At the time of the transaction, it is expected that Seneca-Upshur will
have  cash in  excess  of $350  million  based  on the  initial  offering  price
assumptions set forth below.  This KeySpan  subsidiary  plans to use the cash to
make additional investments in energy related assets.

Of the 10.8  million  shares that  Houston  Exploration  expects to receive from
KeySpan,  Houston Exploration intends to retire approximately 4.6 million shares
and plans to offer 6.2 million shares of common stock in a public offering.

The value of the exchange  will be dependent  on the  ultimate  public  offering
price of the Houston  Exploration  shares in the  offering.  Assuming an initial
public  offering  price of $45.01 (which is the May 21,2004,  NYSE last sale for
Houston  Exploration),  KeySpan  will receive a per share value equal to $40.09,
before  expenses.  The value per share  received  by KeySpan  will  increase  or





decrease,  as  the  case  may  be,  by  approximately  $0.51  per  share  for  a
corresponding  $1.00 increase or decrease in the public offering price of $45.01
per share.

This transaction will reduce KeySpan's ownership interest in Houston Exploration
to  approximately  24% from the current 55% level with the number of outstanding
shares being reduced from approximately 17.4 million shares to approximately 6.6
million shares. In addition, three of KeySpan's five designated directors on the
Houston  Exploration  Board will resign at the closing of the  transaction,  and
KeySpan will retain the right to nominate two of the remaining  seven  directors
on the Houston Exploration Board.

Consummation of this  transaction is subject to each party's  satisfaction  with
the public  offering  price.  Accordingly,  no  assurance  can be given that the
transaction  will be completed.  The  underwriters  will be granted an option to
purchase  an   additional   930,000   shares  of  common   stock  to  cover  any
over-allotments.   If  this  over-allotment  is  exercised  in  full,  KeySpan's
ownership  interest  in Houston  Exploration  will be  reduced to  approximately
22.5%.

This press release shall not constitute an offer to sell or the  solicitation of
an offer to buy nor shall there be any sale of these  securities in any state in
which such offer,  solicitation  or sale would be unlawful prior to registration
or qualification under the securities law of any state.

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A member of the Standard & Poor's 500 Index,  KeySpan Corporation  (NYSE:KSE) is
the fifth  largest  distributor  of  natural  gas in the  United  States and the
largest  in the  Northeast,  operating  regulated  gas  utilities  in New  York,
Massachusetts  and  New  Hampshire,   serving  2.5  million   customers.   These
customer-focused businesses are complemented by a portfolio of service companies
which  offer  energy-related  products,  services  and  solutions  to homes  and
businesses. KeySpan is also the largest electric generator in New York State. We
own approximately 6,600 megawatts of generating capacity, providing power to 1.1
million  customers  of the  Long  Island  Power  Authority  on Long  Island  and
supplying  approximately  25  percent  of New York  City's  capacity  needs.  In
addition to these  assets,  KeySpan  has  strategic  investments  in natural gas
exploration, production, pipeline transportation,  distribution and storage, and
Canadian gas processing.  KeySpan has headquarters in Brooklyn,  New England and
Long   Island.   For   more   information,   visit   KeySpan's   web   site   at
www.keyspanenergy.com.

Certain  statements  contained  herein  are  forward-looking  statements,  which
reflect  numerous  assumptions  and  estimates and involve a number of risks and
uncertainties.  For these statements, we claim the protection of the safe harbor
for  forward-looking  statements  provided by the Private Securities  Litigation
Reform Act of 1995. There are possible  developments that could cause our actual
results  to  differ   materially   from  those   forecast   or  implied  in  the
forward-looking  statements.  You are cautioned  not to place undue  reliance on
these forward-looking statements,  which are current only as of the date of this
filing.  We  disclaim  any  intention  or  obligation  to update  or revise  any
forward-looking  statements,  whether  as a result  of new  information,  future
events or otherwise. Among the factors that could cause actual results to differ
materially are: general economic conditions,  especially in the Northeast United
States;  available  sources and costs of fuel;  volatility of energy prices in a
deregulated  market environment as well as in the source of natural gas and fuel
used to generate electricity;  potential write-down of our investment in natural
gas properties  when natural gas prices are depressed or if we have  significant
downward  revisions  in our  estimated  proved gas  reserves;  federal and state
regulatory  initiatives that increase competition,  threaten cost and investment
recovery and impact rate structure;  our ability to successfully reduce our cost
structures;  implementation of new accounting standards;  the degree to which we
develop unregulated  business ventures,  as well as federal and state regulatory
policies  affecting our ability to retain and operate those  business  ventures;
our  ability to identify  and make  complementary  acquisitions,  as well as the
successful  integration of those acquisitions;  inflationary trends and interest
rates; and risks detailed from time to time in reports and other documents filed
by us with the Securities and Exchange Commission.

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